Clinical Features of Malignant Hypertension with Thrombotic Microangiopathy

Early administration of caplacizumab combined with plasma exchange for thrombotic microangiopathy due to malignant hypertension: a case report

Both thrombotic thrombocytopenic purpura (TTP) and malignant hypertension (MHT) present with thrombotic microangiopathy (TMA). Combination therapy with caplacizumab, anti-von Willebrand factor (VWF) A1 domain antibody, and plasma exchange (PE) has recently been highlighted as a novel therapeutic option for TTP. We treated a 51-year-old woman who showed severe hypertension, retinopathy, and acute kidney injury. Level of consciousness was clear on admission, but low-grade fever was observed. Laboratory tests showed normocytic anemia, thrombocytopenia, renal dysfunction, and a slight decrease in haptoglobin. Neither disseminated intravascular coagulation nor leukemia was diagnosed. The patient emergently received intravenous antihypertensive therapy, continuous hemodiafiltration, and sufficient blood transfusion. However, thrombocytopenia and oliguria remained despite control of blood pressure. On hospital day 8, administration of caplacizumab combined with PE was initiated before receiving results for a disintegrin-like and metalloprotease with thrombospondin type 1 motifs 13 (ADAMTS13) activity and inhibitor levels. We then administered caplacizumab for 5 days and performed 2 sessions of PE until confirming ADAMTS13 activity of 42% and absence of its inhibitor, contributing to increased serum hemoglobin and platelet levels with cessation of dialysis. Renal biopsy findings on hospital day 20 showed arteriolar nephrosclerosis and intimal hyperplasia in small arteries. To the best of our knowledge, this represents the first description of MHT-induced TMA treated with caplacizumab. MHT-induced TMA exhibiting symptoms of TTP tends to show poor renal prognosis, so early administration of caplacizumab with PE before receiving results for ADAMTS13 might prove beneficial for cases in which MHT complicated with TTP is suspected.

Malignant hypertension: current challenges, prevention strategies, and future perspectives

Introduction

Based on office blood pressure (BP) values, hypertension is categorized into three stages: stage 1 (140-159/90-99 mmHg), stage 2 (160-179/100-109 mmHg), and stage 3 (≥180/≥110 mmHg). Malignant hypertension (MHT) is characterized by extreme BP elevation (systolic blood pressure above 200 mmHg and diastolic blood pressure above 130 mmHg) and acute microvascular damage affecting various organs, particularly the retinas, brain, and kidneys.

Objectives

The pathogenesis, predisposing variables, therapy, and preventive strategies for MHT were examined in this review.

Conclusions and recommendations

Malignant hypertension requires prompt and efficient treatment because it is the most severe kind of hypertension that affects target organs. At the same time, there are a number of alternatives available for treating MHT. The International Society of Hypertension 2020 and European Society of Cardiology/European Society of Hypertension 2018 recommendations suggest using labetalol and nicardipine as the first-line choice, with urapidil and nitroprusside serving as alternative medications. Elevated risk of MHT has been linked to many socio-demographic and genetic factors.

Factors Predicting Renal Outcomes in Hypertensive Emergencies With Severe Renal Impairment: A Single-Center Retrospective Study

Background and Aims

Hypertensive emergencies, characterized by elevated blood pressure (BP) and multiple organ damage, have poor prognosis. Patients occasionally show gradual improvement in renal function with appropriate antihypertensive treatment despite renal impairment. However, reports analyzing factors predicting prognosis in patients with hypertensive emergencies and severe renal impairment are limited. This retrospective study aimed to investigate clinical features and predictors of renal outcomes in such patients.

Methods

Patients admitted to our hospital diagnosed with hypertensive emergency with severe renal impairment (serum creatinine [Cr] level > 2.5 mg/dL) between 2007 and 2021, were enrolled and divided into two groups: those who received renal replacement therapy (RRT) after 3 years (RRT group) and those who did not (non-RRT group); clinical characteristics and laboratory data were compared.

Results

Fifteen patients were enrolled, with a median age and serum Cr level of 48 years and 5.97 mg/dL, respectively. No significant between-group difference was observed in serum Cr levels or kidney size. However, the non-RRT group exhibited significantly higher levels of serum lactate dehydrogenase (LDH) levels and significantly lower platelet counts (PLT), suggesting development of microangiopathic hemolysis due to severe endothelial damage. Furthermore, the non-RRT group exhibited lower serum potassium levels than the RRT group, accompanied by high plasma renin activity and serum aldosterone levels, suggesting activation of the renin-angiotensin system (RAS). In the non-RRT group, serum Cr, LDH, potassium levels, and PLT improved significantly after treatment.

Conclusions

Serum LDH, potassium levels, and PLT are useful predictors of renal prognosis in hypertensive emergencies with extremely poor renal function. In some cases, severe renal damage can be ameliorated by appropriate antihypertensive therapy. A positive response to treatment often signifies a favorable prognosis. Furthermore, early initiation of RAS inhibitors may be beneficial for lowering BP and providing renal protection.

Role of aldosterone in various target organ damage in patients with hypertensive emergency: a cross-sectional study

BACKGROUND

Hypertensive emergency is a critical disease that causes multiple organ injuries. Although the renin-angiotensin-aldosterone system (RAS) is enormously activated in this disorder, whether the RAS contributes to the development of the organ damage has not been fully elucidated. This cross-sectional study was conducted to characterize the association between RAS and the organ damage in patients with hypertensive emergencies.

METHODS

We enrolled 63 patients who visited our medical center with acute severe hypertension and multiple organ damage between 2012 and 2020. Hypertensive target organ damage was evaluated on admission, including severe kidney impairment (eGFR less than 30 mL/min/1.73 m2, SKI), severe retinopathy, concentric left ventricular hypertrophy (c-LVH), thrombotic microangiopathy (TMA), heart failure with reduced ejection fraction (HFrEF) and cerebrovascular disease. Then, whether each organ injury was associated with blood pressure or a plasma aldosterone concentration was analyzed.

RESULTS

Among 63 patients, 31, 37, 43 and 8 cases manifested SKI, severe retinopathy, c-LVH and ischemic stroke, respectively. All populations with the organ injuries except cerebral infarction had higher plasma aldosterone concentrations than the remaining subset but exhibited a variable difference in systolic or diastolic blood pressure. Twenty-two patients had a triad of SKI, severe retinopathy and c-LVH, among whom 5 patients manifested TMA. Furthermore, the number of the damaged organs was correlated with plasma aldosterone levels (Spearman's coefficient = 0.50), with a strong association observed between plasma aldosterone (≥ 250 pg/mL) and 3 or more complications (odds ratio = 9.16 [95%CI: 2.76-30.35]).

CONCLUSION

In patients with hypertensive emergencies, a higher aldosterone level not only contributed to the development of the organ damage but also was associated with the number of damaged organs in each patient.

Kidney Outcomes Following Angiotensin Receptor-Neprilysin Inhibitor vs Angiotensin-Converting Enzyme Inhibitor/Angiotensin Receptor Blocker Therapy for Thrombotic Microangiopathy

Importance

Thrombotic microangiopathy (TMA) on kidney biopsy is a pattern of endothelial injury commonly seen in malignant hypertension (mHTN), but treatment strategies are not well established.

Objective

To evaluate the kidney outcomes of angiotensin receptor-neprilysin inhibitor (ARNI), specifically sacubitril/valsartan, vs angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) therapy for patients with mHTN-associated TMA.

Design, Setting, and Participants

This single-center cohort study enrolled consecutive patients in China diagnosed with mHTN-associated TMA through kidney biopsy from January 2008 to June 2023. Follow-up was conducted until the conclusion of the study period. Data were analyzed in September 2023.

Exposures

Treatment with sacubitril/valsartan or ACEI/ARBs during hospitalization and after discharge.

Main Outcomes and Measures

The primary outcome was a composite of kidney recovery: a 50% decrease in serum creatinine level, decrease in serum creatinine levels to the reference range, or kidney survival free from dialysis for more than 1 month. The secondary and tertiary outcomes were a 15% increase in the estimated glomerular filtration rate (eGFR) relative to baseline and kidney survival free from dialysis, respectively. Propensity score matching (PSM) and Cox proportional hazards regression analysis were used to evaluate the association between sacubitril/valsartan and ACEI/ARB therapy with kidney recovery outcomes.

Results

Among the 217 patients (mean [SD] age, 35.9 [8.8] years; 188 men [86.6%]) included in the study, 66 (30.4%) received sacubitril/valsartan and 151 (69.6%) received ACEI/ARBs at baseline. Sacubitril/valsartan treatment was associated with shorter time to the primary outcome compared with ACEI/ARB treatment (20 of 63 [31.7%] vs 38 of 117 [32.5%]; adjusted hazard ratio [aHR], 1.85; 95% CI, 1.05-3.23). Sacubitril/valsartan treatment was independently associated with shorter time to a 15% increase in eGFR (15 of 46 [32.6%] vs 46 of 83 [55.4%]; aHR, 2.13; 95% CI, 1.09-4.17) and kidney survival free from dialysis (11 of 23 [47.8%] vs 16 of 57 [28.1%]; aHR, 2.63; 95% CI, 1.15-5.88) compared with ACEI/ARB treatment. These differences remained significant in the PSM comparison.

Conclusions and Relevance

In this cohort study, sacubitril/valsartan treatment was associated with a potential kidney function benefit in patients with mHTN-associated TMA compared with ACEI/ARB treatment. The findings suggested that sacubitril/valsartan could be a superior therapeutic approach for managing this serious condition in terms of kidney recovery.

Clinical characteristics and outcomes of a patient population with atypical hemolytic uremic syndrome and malignant hypertension: analysis from the Global aHUS registry

INTRODUCTION

Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA) often caused by alternative complement dysregulation. Patients with aHUS can present with malignant hypertension (MHT), which may also cause TMA.

METHODS

This analysis of the Global aHUS Registry (NCT01522183) assessed demographics and clinical characteristics in eculizumab-treated and not-treated patients with aHUS, with (n = 71) and without (n = 1026) malignant hypertension, to further elucidate the potential relationship between aHUS and malignant hypertension.

RESULTS

While demographics were similar, patients with aHUS + malignant hypertension had an increased need for renal replacement therapy, including kidney transplantation (47% vs 32%), and more pathogenic variants/anti-complement factor H antibodies (56% vs 37%) than those without malignant hypertension. Not-treated patients with malignant hypertension had the highest incidence of variants/antibodies (65%) and a greater need for kidney transplantation than treated patients with malignant hypertension (65% vs none). In a multivariate analysis, the risk of end-stage kidney disease or death was similar between not-treated patients irrespective of malignant hypertension and was significantly reduced in treated vs not-treated patients with aHUS + malignant hypertension (adjusted HR (95% CI), 0.11 [0.01-0.87], P = 0.036).

CONCLUSIONS

These results confirm the high severity and poor prognosis of untreated aHUS and suggest that eculizumab is effective in patients with aHUS ± malignant hypertension. Furthermore, these data highlight the importance of accurate, timely diagnosis and treatment in these populations and support consideration of aHUS in patients with malignant hypertension and TMA.

TRIAL REGISTRATION DETAILS

Atypical Hemolytic-Uremic Syndrome (aHUS) Registry. Registry number: NCT01522183 (first listed 31st January, 2012; start date 30th April, 2012).

Impact of early initiation of renin-angiotensin blockade on renal function and clinical outcomes in patients with hypertensive emergency: a retrospective cohort study

BACKGROUND

Hypertensive emergency is a critical disease that causes multifaceted sequelae, including end-stage kidney disease and cardiovascular disease. Although the renin-angiotensin-aldosterone (RAA) system is enormously activated in this disease, there are few reports that attempt to characterize the effect of early use of RAA inhibitors (RASi) on the temporal course of kidney function.

METHODS

This retrospective cohort study was conducted to clarify whether the early use of RASi during hospitalization offered more favorable benefits on short-term renal function and long-term renal outcomes in patients with hypertensive emergencies. We enrolled a total of 49 patients who visited our medical center with acute severe hypertension and multiple organ dysfunction between April 2012 and August 2020. Upon admission, the patients were treated with intravenous followed by oral antihypertensive drugs, including RASi and Ca channel blockers (CCB). Kidney function as well as other laboratory and clinical parameters were compared between RASi-treated and CCB- treated group over 2 years.

RESULTS

Antihypertensive treatment effectively reduced blood pressure from 222 ± 28/142 ± 21 to 141 ± 18/87 ± 14 mmHg at 2 weeks and eGFR was gradually restored from 33.2 ± 23.3 to 40.4 ± 22.5 mL/min/1.73m² at 1 year. The renal effect of antihypertensive drugs was particularly conspicuous when RASi was started in combination with other conventional antihypertensive drugs at the early period of hospitalization (2nd day [IQR: 1-5.5]) and even in patients with moderately to severely diminished eGFR (< 30 mL/min/1.73 m²) on admission. In contrast, CCB modestly restored eGFR during the observation period. Furthermore, renal survival probabilities were progressively deteriorated in patients who had manifested reduced eGFR (< 15 mL/min/1.73 m²) or massive proteinuria (urine protein/creatinine ≥ 3.5 g/gCr) on admission. Early use of RASi was associated with a favorable 2-year renal survival probability (0.90 [95%CI: 0.77-1.0] vs. 0.63 [95%CI: 0.34-0.92] for RASi ( +) and RASi (-), respectively, p = 0.036) whereas no apparent difference in renal survival was noted for CCB.

CONCLUSIONS

Early use of RASi contributes to the renal functional recovery from acute reduction in eGFR among patients with hypertensive emergencies. Furthermore, RASi offers more favorable effect on 2-year renal survival, compared with CCB.

Thrombotic microangiopathy in patients with malignant hypertension

BACKGROUND

Thrombotic microangiopathy (TMA) is a complication of malignant hypertension (mHTN) attributed to the high levels of blood pressure (BP). However, no studies have investigated in patients with mHTN of different etiologies whether the presence of TMA is associated with specific causes of mHTN.

METHODS

We investigate the presence of TMA (microangiopathic hemolytic anemia and thrombocytopenia) in a large and well characterized cohort of 199 patients with mHTN of different etiologies (primary HTN 44%, glomerular diseases 16.6%, primary atypical hemolytic uremic syndrome (aHUS) 13.1%, renovascular HTN 9.5%, drug-related HTN 7%, systemic diseases 5.5%, endocrine diseases 4.5%). Outcomes of the study were kidney recovery and kidney failure.

RESULTS

Patients with TMA (40 cases, 20.1%) were younger, had a lower proportion of males, lower BP levels and worse kidney function at presentation. Their underlying diseases were primary aHUS (60%), drug-related mHTN (15%), glomerular diseases (all of them IgA nephropathy) (10%), systemic diseases (10%) and primary HTN (5%). The presence of TMA was 92.3% in primary aHUS, 42.9% in drug-related HTN, 36.4% in systemic diseases, 12.1% in glomerular diseases and 2.3% in primary HTN. No patient with renovascular HTN or mHTN caused by endocrine diseases developed TMA, despite BP levels as severe as patients with TMA. A higher proportion of TMA patients developed kidney failure as compared to patients without TMA (56.4% versus 38.9%, respectively).

CONCLUSIONS

The presence of TMA in patients with mHTN should guide the diagnosis towards primary aHUS, drug-related mHTN, some systemic diseases and IgA nephropathy, while it is exceptional in other causes of mHTN.

Thrombotic Microangiopathy Syndromes-Common Ground and Distinct Frontiers

Thrombotic microangiopathies (TMAs) have in common a terminal phenotype of microangiopathic hemolytic anemia with end-organ dysfunction. Thrombotic thrombocytopenic purpura results from von Willebrand factor multimerization, Shiga toxin-mediated hemolytic uremic syndrome causes toxin-induced endothelial dysfunction, while atypical hemolytic uremic syndrome results from complement system dysregulation. Drug-induced TMA, rheumatological disease-induced TMA, and renal-limited TMA exist in an intermediate space that represents secondary complement activation and may overlap with atypical hemolytic uremic syndrome clinically. The existence of TMA without microangiopathic hemolytic features, renal-limited TMA, represents an undiscovered syndrome that responds incompletely and inconsistently to complement blockade. Hematopoietic stem cell transplant-TMA represents another more resistant form of TMA with different therapeutic needs and clinical course. It has become apparent that TMA syndromes are an emerging field in nephrology, rheumatology, and hematology. Much work remains in genetics, molecular biology, and therapeutics to unravel the puzzle of the relationships and distinctions apparent between the different subclasses of TMA syndromes.

What is the impact of blood pressure on neurological symptoms and the risk of ESKD in primary and secondary thrombotic microangiopathies based on clinical presentation: a retrospective study

Background

The impact of blood pressure on neurological symptoms and risk of end-stage kidney disease (ESKD) is unknown in primary and secondary thrombotic microangiopathies (TMAs).

Methods

We measured baseline systolic (SBP) and diastolic (DBP) BP in consecutive 563 patients with adjudicated primary and secondary TMAs, and assessed its association with the risk of ESKD.

Results

Normal BP, grade 1, 2 and 3 hypertension were present in 243 (43.1%), 132 (23.4%), 101 (17.9%) and 88 (15.6%), respectively.

Significant BP differences were noted in relation to the cause of TMA: highest BP values were found in patients with atypical hemolytic-uremic syndrome (aHUS), pregnancy, transplantation and auto-immune-related TMAs. Normal BP or grade 1 hypertension was found in 17/18 (94.4%) patients with thrombotic thrombocytopenic patients (only 1/18 (5.6%) had a SBP value>150 mmHg). In contrast, BP values could not differentiate isolated “essential” malignant hypertension (MH) from MH associated with aHUS (isolated MH (n=15): BP (median (IQR)): 220 (182-249)/132 (101-150) mmHg; MH with aHUS (n=5): BP: 223 (196-245)/131 (111-144) mmHg).

The risk of vigilance disturbances (6.9%, 15.0%, 25.0%, respectively), epileptic seizures (1.5%, 4.0%, 12.5%, respectively) and posterior reversible encephalopathy syndrome (0.76%, 2.97%, 6.82%, respectively) increased with increasing baseline BP values from grade 1 to grade 3 hypertension.

ESKD occurred in 35/563 (6.2%) patients (1.23%, 2.27%, 11.9% and 19.3% of patients with normal BP, grade 1, 2 and 3 hypertension, respectively). As compared to patients with normal BP (<120/139 mmHg), grade 1, grade 2 and grade 3 hypertension were associated with a greater risk of ESKD in univariate (OR: 1.91 [0.83-4.40], 13.2 [3.56-48.9] and 34.8 [9.31-130], respectively) and multivariate (OR: 0.89 [0.30-2.69], 7.00 [1.57-31.3] and 19.7 [4.53-85.2], respectively) analyses. The association between BP and the risk of ESRD was unchanged after adjustment on eculizumab use (OR: 3.46 [1.41-8.49], 17.7 [4.44-70.0] and 70.6 [8.61-579], respectively). Patients with MH, regardless of its cause, had a greater risk of ESKD (OR: 26.4 [10.0-69.8] vs other patients).

Conclusions

Baseline BP differs in primary and secondary TMAs. High BP reduces the neurological tolerance of TMAs and is a powerful independent risk factor of ESKD, even after adjustment on TMA’s cause.

Primary Hyperaldosteronism: A Rare Cause of Malignant Hypertension with Thrombotic Microangiopathy in a Kidney Transplant Recipient

Thrombotic microangiopathy (TMA) is a rare disease that presents with haemolysis and organ damage. The kidney is one of the main affected organs, and TMA is associated with serious complications and increased mortality. In transplanted patients, TMA is even less common and has a variety of possible causes, including thrombotic thrombocytopenic purpura (TTP) and haemolytic-uremic syndrome (HUS), infections, drugs, autoimmune disease, tumours, and malignant hypertension. Transplant-related causes, such as antibody-mediated rejection, calcineurin inhibitors, and viral infections, need to be considered as well. The authors report a rare case of TMA in a kidney transplant recipient, whose investigation revealed malignant hypertension secondary to primary hyperaldosteronism.

The standard of care for immune thrombotic thrombocytopenic purpura today

Targeted therapy of immune thrombotic thrombocytopenic purpura (iTTP) requires acurate and prompt diagnosis and differentiation from complement-mediated hemolytic uremic syndrome and other causes of thrombotic microangiopathy. ADAMTS-13 (A Disintegrin And Metalloprotease with ThromboSpondin-1 Domain, member 13) evaluation (activity and inhibitors or anti-ADAMTS-13 IgG) is the key for diagnosis and further management of patients with suspected iTTP during acute episode and in clinical response or remission. Clinical trial results and real-world data have demonstrated the efficacy and safety of the triple therapy consisting of therapeutic plasma exchange, caplacizumab, and immunosuppressives (e.g., corticosteroids and rituximab) for acute iTTP. Such a therapeutic strategy has significantly accelerated the normalization of platelet counts, decreased the length of stays in the intensive care unit and the hospital, but most importantly reduced the mortality rate. The present review highlights some of the important advancements for the diagnosis and management of iTTP and proposes triple therapy as the standard of care for acute iTTP today.

Hypertension Management in Emergency Departments

BACKGROUND

Elevated blood pressure (BP) is pervasive among patients that visit emergency departments (EDs) for their care.

METHODS

In this review article, we outline the current approach to the management of these individuals and highlight the crucial role emergency medicine clinicians play in reducing the morbidity associated with elevated BP.

RESULTS

We highlight the critical importance of immediate treatment when elevated BP contributes to new or worsening end-organ injury but emphasize that such hypertensive emergencies are rare. For the vast majority of patients with elevated BP in the ED who do not have new or worsening end-organ injury from elevated BP, immediate BP reduction within the ED is not recommended or safe. Nonetheless, within weeks after an ED visit, there is a pressing need to improve the care of patients with elevated or previously undiagnosed hypertension. For many, it may be their only regular point of engagement with the healthcare system. To address this, we present novel perspectives that envision a new role for emergency medicine in chronic hypertension management-one that acknowledges the significant population-level gaps in BP control that contribute to disparities in cardiovascular disease and sets the stage for future changes in systems-based practice.

CONCLUSIONS

Emergency medicine plays a key and evolving role in reducing morbidity associated with elevated BP.

Correlations Between Interleukin-11 Expression and Hypertensive Kidney Injury in a Rat Model of Renovascular Hypertension

BACKGROUND

Interleukin-11 (IL-11) is a pleiotropic cytokine of the interleukin-6 family. Recent studies revealed its crucial role in the development of cardiovascular fibrosis. In this study we examined IL-11 expression levels in the heart and the kidney exposed to high blood pressure in renovascular hypertensive rats and their correlations to fibrotic markers and kidney injury.

METHODS

Two-kidney, one-clip renovascular hypertension (2K1C) was induced in rats. IL-11 expression was measured by real-time polymerase chain reaction in the left ventricle and the right kidney. The correlation of cardiac IL-11 expression with biomarkers of renal fibrosis was assessed. We further investigated IL-11 expression in 2K1C rats grouped into rats with malignant vs. nonmalignant hypertension (distinguishing criteria: weight loss, number of fibrinoid necrosis, and onion skin lesions).

RESULTS

Thirty-five days after clipping, mean arterial pressure was significantly increased in 2K1C. Renal IL-11 expression was elevated in 2K1C. In the heart there was only a trend toward higher IL-11 expression in 2K1C. IL-11 in the kidney in 2K1C correlated with the expression of transforming growth factor (TGF)-β1/2, collagens, fibronectin, osteopontin, as well as tissue inhibitors of metalloprotease 1/2. There were also correlations of IL-11 with tissue collagen expansion, number of activated fibroblasts and serum creatinine, but no correlation with mean arterial pressure. Renal expression of IL-11 was highest in rats with malignant hypertension.

CONCLUSIONS

Renal IL-11 expression of renovascular hypertensive rats is markedly increased and correlates with profibrotic markers and loss of function and might therefore serve as a biomarker for the severity of hypertensive nephrosclerosis.

Atypical hemolytic uremic syndrome and complement blockade: established and emerging uses of complement inhibition

PURPOSE OF REVIEW

Atypical hemolytic uremic syndrome (aHUS) is a diagnosis that has captured the interest of specialists across multiple fields. The hallmark features of aHUS are microangiopathic hemolysis and thrombocytopenia, which creates a diagnostic dilemma because of the occurrence of these findings in a wide variety of clinical disorders.

RECENT FINDINGS

In most of the instances, aHUS is a diagnosis of exclusion after ruling out causes such as Shigella toxin, acquired or genetic a disintegrin and metalloproteinase thrombospondin motif 13 deficiency (thrombotic thrombocytopenic purpura), and vitamin B12 deficiency. In the purest sense, aHUS is a genetic condition that is activated (or unmasked) by an environmental exposure. However, it is now evident that complement activation is a feature of many diseases. Variants in complement regulatory genes predispose to microangiopathic hemolysis in many rheumatologic, oncologic, and drug-induced vascular, obstetric, peritransplant, and infectious syndromes.

SUMMARY

Many 'hemolysis syndromes' overlap clinically with aHUS, and we review the literature on the treatment of these conditions with complement inhibition. New reports on the treatment of C3 glomerulopathy, Shiga toxin-related classic hemolytic uremic syndrome, and medication-related thrombotic microangiopathy will be reviewed as well.

A Case of Rheumatoid Arthritis Presenting with Renal Thrombotic Microangiopathy Probably due to a Combination of Chronic Tacrolimus Arteriolopathy and Severe Hypertension

A 51-year-old woman with rheumatoid arthritis presented with mild hypertension 20 months after tacrolimus treatment and developing proteinuria 24 months after the treatment. Tacrolimus was discontinued 27 months after the treatment, followed by heavy proteinuria, accelerated hypertension, and deteriorating renal function without ocular fundus lesions as a clinical sign of malignant hypertension. Renal biopsy revealed malignant nephrosclerosis characterized by subacute and chronic thrombotic microangiopathy (TMA), involving small arteries, arterioles, and glomeruli. Focal segmental glomerulosclerosis, probably secondary to chronic TMA, was identified as a cause of heavy proteinuria. The zonal tubulointerstitial injury caused by subacute TMA may have mainly contributed to deteriorating renal function. The presence of nodular hyalinosis in arteriolar walls was indicative of tacrolimus-associated nephrotoxicity. Together with other antihypertensive drugs, administration of aliskiren stabilized renal function with reducing proteinuria. Owing to the preexisting proteinuria prior to severe hypertension and the complex renal histopathology, we postulated that chronic TMA, which was initially triggered by tacrolimus, was aggravated by severe hypertension, resulting in overt renal TMA.

Secondary thrombotic microangiopathy and eculizumab: A reasonable therapeutic option

Understanding the role of the complement system in the pathogenesis of atypical haemolytic uraemic syndrome and other thrombotic microangiopathies (TMA) has led to the use of anti-complement therapy with eculizumab in these diseases, in addition to its original use in patients with paroxysmal nocturnal haemoglobinuria andatypical haemolytic uraemic syndrome. Scientific evidence shows that both primary and secondary TMAs with underlying complement activation are closely related. For this reasons, control over the complement system is a therapeutic target. There are 2scenarios in which eculizumab is used in patients with TMA: primary or secondary TMA that is difficult to differentiate (including incomplete clinical presentations) and complement-mediated damage in various processes in which eculizumab proves to be efficacious. This review summarises the evidence on the role of the complement activation in the pathophysiology of secondary TMAs and the efficacy of anti-complement therapy in TMAs secondary to pregnancy, drugs, transplant, humoral rejection, systemic diseases and glomerulonephritis. Although experience is scarce, a good response to eculizumab has been reported in patients with severe secondary TMAs refractory to conventional treatment. Thus, the role of the anti-complement therapy as a new treatment option in these patients should be investigated.

Hemolytic Uremic Syndrome: An Increasingly Recognized Public Health Problem

A 28-year-old man was referred and admitted to our hospital due to Escherichia coli O157-mediated hemorrhagic colitis with severe thrombocytopenia. A systemic workup concluded that the patient had acute pancreatitis as well as hemolytic uremic syndrome. The patient was ultimately discharged, with his platelet count having recovered. Our case serves an illustrative example of potentially serious complications of an increasingly recognized public health problem. Systemic studies on this topic are insufficient, and we strongly recommend the further accumulation of more experiences like ours. Several diagnostic and management concerns that emerged in this case are also discussed.

Severe renal failure and thrombotic microangiopathy induced by malignant hypertension successfully treated with spironolactone

Malignant hypertension can cause thrombotic microangiopathy (TMA) characterized by hemolytic anemia and thrombocytopenia. On the other hand, severe hypertension is sometimes associated with hemolytic uremic syndrome (HUS) or thrombotic thrombocytopenic purpura (TTP). Distinguishing these entities is important because of therapeutic implications. Plasmapheresis should be initiated as soon as possible if we are dealing with TTP. We describe the case of a 30-year-old man referred to our hospital with malignant hypertension, severe renal failure and TMA: haemoglobin=9g/dL, total bilirubin=0.4mg/dL, haptoglobin≤10mg/dL, platelet count=59,000/μL and schistocytes on peripheral smear. He required initiation of hemodialysis. Additionally, we considered that the possible cause of TMA was malignant hypertension according to the presence of hypertensive retinopathy and thrombocytopenia which remitted only with blood pressure control, hence, plasmapheresis was not given. Renal function did not improve and the patient remained chronic hemodialysis. Intensive therapy for hypertension with a combination of antihypertensive drugs including spironolactone successfully lowered his blood pressure without developing hyperkalemia.

Thrombotic Microangiopathy and the Kidney

Thrombotic microangiopathy can manifest in a diverse range of diseases and is characterized by thrombocytopenia, microangiopathic hemolytic anemia, and organ injury, including AKI. It can be associated with significant morbidity and mortality, but a systematic approach to investigation and prompt initiation of supportive management and, in some cases, effective specific treatment can result in good outcomes. This review considers the classification, pathology, epidemiology, characteristics, and pathogenesis of the thrombotic microangiopathies, and outlines a pragmatic approach to diagnosis and management.

Complement C5-inhibiting therapy for the thrombotic microangiopathies: accumulating evidence, but not a panacea

Thrombotic microangiopathy (TMA), characterized by organ injury occurring consequent to severe endothelial damage, can manifest in a diverse range of diseases. In complement-mediated atypical haemolytic uraemic syndrome (aHUS) a primary defect in complement, such as a mutation or autoantibody leading to over activation of the alternative pathway, predisposes to the development of disease, usually following exposure to an environmental trigger. The elucidation of the pathogenesis of aHUS resulted in the successful introduction of the complement inhibitor eculizumab into clinical practice. In other TMAs, although complement activation may be seen, its role in the pathogenesis remains to be confirmed by an interventional trial. Although many case reports in TMAs other than complement-mediated aHUS hint at efficacy, publication bias, concurrent therapies and in some cases the self-limiting nature of disease make broader interpretation difficult. In this article, we will review the evidence for the role of complement inhibition in complement-mediated aHUS and other TMAs.

Malignant Hypertension Revisited-Does This Still Exist?

Malignant or accelerated hypertension is the most severe form of hypertension, defined clinically by very high blood pressure (diastolic above 130 mm Hg) accompanied by bilateral retinal hemorrhages and/or exudates, with or without papilledema. The aim of this review is to discuss if malignant hypertension still poses a clinically relevant entity and to highlight the diagnostic challenges of this form of hypertension. The substantial improvement in prognosis in patients with malignant hypertension over the last decades is well documented, but there is no strong evidence to suggest a significant change in its incidence. In fact, with the growing population and improving life expectancy, malignant hypertension is likely to become even more prevalent worldwide, especially in the developing countries with less advanced health care services. Despite simple diagnostic criteria of malignant hypertension, the diagnoses may be difficult in many patients. Malignant hypertension patients often have the diagnosis established only when the target organ damage occur. Furthermore, retrospective diagnosis is problematic, as malignant hypertensive retinopathy gradually resolves over a relatively short period of time, while persistent target organ damage will, however, lead to the development of complications and much poorer prognosis than in nonmalignant hypertension patients. Certainly, malignant hypertension still poses a clinically relevant and challenging form of hypertension and its possibility should be always considered during the assessment of patients with poorly controlled hypertension.

Atypical hemolytic uremic syndrome in the setting of complement-amplifying conditions: case reports and a review of the evidence for treatment with eculizumab

Atypical hemolytic uremic syndrome (aHUS) is a rare, genetic, progressive, life-threatening form of thrombotic microangiopathy (TMA) predominantly caused by dysregulation of the alternative pathway of the complement system. Complement-amplifying conditions (CACs), including pregnancy complications [preeclampsia, HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome], malignant hypertension, autoimmune diseases, transplantation, and others, are associated with the onset of TMA in up to 69 % of cases of aHUS. CACs activate the alternative pathway of complement and may be comorbid with aHUS or may unmask a previously undiagnosed case. In this review, three case reports are presented illustrating the onset and diagnosis of aHUS in the setting of different CACs (pregnancy complications, malignant hypertension, renal transplantation). The report also reviews the evidence for a variety of CACs, including those mentioned above as well as infections and drug-induced TMA, and the overlap with aHUS. Finally, we introduce an algorithm for diagnosis and treatment of aHUS in the setting of CACs. If TMA persists despite initial management for the specific CAC, aHUS should be considered. The terminal complement inhibitor eculizumab should be initiated for all patients with confirmed diagnosis of aHUS, with or without a comorbid CAC.

Thrombotic Microangiopathy Care Pathway: A Consensus Statement for the Mayo Clinic Complement Alternative Pathway-Thrombotic Microangiopathy (CAP-TMA) Disease-Oriented Group

Thrombotic microangiopathies (TMAs) comprise a heterogeneous set of conditions linked by a common histopathologic finding of endothelial damage resulting in microvascular thromboses and potentially serious complications. The typical clinical presentation is microangiopathic hemolytic anemia accompanied by thrombocytopenia with varying degrees of organ ischemia. The differential diagnoses are generally broad, while the workup is frequently complex and can be confusing. This statement represents the joint recommendations from a multidisciplinary team of Mayo Clinic physicians specializing in the management of TMA. It comprises a series of evidence- and consensus-based clinical pathways developed to allow a uniform approach to the spectrum of care including when to suspect TMA, what differential diagnoses to consider, which diagnostic tests to order, and how to provide initial empiric therapy, as well as some guidance on subsequent management.

[Clinical and etiological profile malignant hypertension in children in pediatric intensive care]

INTRODUCTION

Malignant hypertension (HTA), pediatrics, is unique by its clinical presentation, defined as severe hypertension accompanied by ischemic failure of one or more organs.

METHODS-PATIENTS

Retroprospective study of cases of children admitted to pediatric intensive care. We chose a decline of 10 years from September 1994 to December 2004 for the first time, and from January 2005 to December 2015 for the second period; and we identified the cases presenting malignant hypertension (mHTA).

RESULTS

Sixty-six patients were included, a prevalence of 0.6%. The age of patients ranged from 12months to 16years. The symptoms are related to the consequences of hypertension or condition in question. The most found signs are headache in more than 7%. Cerebrovascular event in 6%. A hypertensive convulsive encephalopathy 33.3% of patients. Renal disease is common, of varying severity. A fundus retinopathy was found in 47% stage 3, stage 4 in 51%. mHTA defined for the mean SBP values of 175mmHg and DBP average 112,5mmHg is often secondary to renal causes. The treatment is symptomatic with antihypertensive associated with the etiological treatment. Evolution is good out of 7 deaths.

CONCLUSION

mHTA is a rare condition in the pediatric population. The clinical signs of functional rich under their impact on vital organs. The support must be early in intensive care.

Clinico-pathological characteristics and outcomes of patients with biopsy-proven hypertensive nephrosclerosis: a retrospective cohort study

Background

This study aimed to investigate renal outcomes and their predictors in biopsy-proven hypertensive nephrosclerosis (HN) patients and to compare clinico-pathological characteristics and prognoses between benign nephrosclerosis (BN) and malignant nephrosclerosis (MN) patients.

Methods

Data for biopsy-proven HN patients were retrospectively analyzed. Renal survival rates and relationships between clinico-pathological characteristics and outcomes were assessed.

Results

A total of 194 patients were enrolled; the mean age at biopsy was 43.8 years, and male gender predominated (82.5 %). The median duration of hypertension was 5.0 years, and the mean systolic and diastolic blood pressures were 195 ± 37 and 126 ± 26 mmHg, respectively. The median serum creatinine (Scr) level, estimated glomerular filtration rate (eGFR), and proteinuria level were 1.61 mg/dl, 49.6 ml/min/1.73 m², and 0.80 g/24 h, respectively. BN and MN were found by renal biopsy in 55.2 % and 44.8 % of patients, respectively. At biopsy, MN patients were younger, and had higher median Scr and proteinuria levels, higher incidences of anemia, hypertensive heart disease and hypertensive retinopathy, and worse renal outcomes than BN patients. During a median follow-up period of 3.0 years, 36 patients (18.6 %) reached end-stage renal disease (ESRD), and the 5- and 10-year cumulative renal survival rates for HN patients were 84.5 % and 48.9 %, respectively. A decreased baseline eGFR, an increased baseline proteinuria level, anemia, increased percentage of global glomerulosclerosis and tubular atrophy and interstitial fibrosis (TAIF) were independent predictors of future ESRD.

Conclusions

The clinico-pathological characteristics and prognoses were significantly different between the MN and BN patients. The renal outcomes of HN patients were independently associated with the baseline eGFR and proteinuria level, anemia, percentage of global glomerulosclerosis and TAIF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0254-2) contains supplementary material, which is available to authorized users.

Hypertensive Urgencies and Emergencies in the Hospital Setting

The prevalence of hypertension in the general population has steadily climbed over the past several decades and hypertension is a primary or secondary diagnosis in nearly a fourth of hospitalized adults. Hospitalization is often a time of pertubation in a patient's usual blood pressure control, with pain, anxiety and missed medications all risk factors for severe hypertension. Hospitalists are often faced with severe hypertension in a patient not previously known to them and this presents a challenge of how best to assess the clinical importance of blood pressure elevation. An additional challenge is the lack of literature to guide the optimal management of hypertension in inpatients. This review aims to describe the scope of the problem, to describe the near and long-term risks of overzealous blood pressure management, and to identify areas for future study.

Malignant Hypertension with Thrombotic Microangiopathy

A 49-year-old man with malignant hypertension, acute kidney injury and mental deterioration was referred to our hospital. We initially observed microangiopathic hemolytic anemia, thrombocytopenia and kidney damage, indicating he had thrombotic microangiopathy (TMA). We considered TMA was caused by malignant hypertension and therefore did not start plasma therapy. The French TMA reference center reported that platelet counts and serum creatine levels have high values for predicting severe ADAMTS13 deficiency. The patient fully recovered from his illness after treatment with antihypertensive drugs and intermittent hemodialysis. This case might thus be useful to understand the proper differential diagnosis and treatment of TMA.

The global aHUS registry: methodology and initial patient characteristics

Background

Atypical hemolytic uremic syndrome (aHUS) is a rare, genetically-mediated systemic disease most often caused by chronic, uncontrolled complement activation that leads to systemic thrombotic microangiopathy (TMA) and renal and other end-organ damage.

Methods

The global aHUS Registry, initiated in April 2012, is an observational, noninterventional, multicenter registry designed to collect demographic characteristics, medical and disease history, treatment effectiveness and safety outcomes data for aHUS patients. The global aHUS Registry will operate for a minimum of 5 years of follow-up. Enrollment is open to all patients with a clinical diagnosis of aHUS, with no requirement for identified complement gene mutations, polymorphisms or autoantibodies or particular type of therapy/management.

Results

As of September 30, 2014, 516 patients from 16 countries were enrolled. At enrollment, 315 (61.0 %) were adults (≥18 years) and 201 (39.0 %) were <18 years of age. Mean (standard deviation [SD]) age at diagnosis was 22.7 (20.5) years. Nineteen percent of patients had a family history of aHUS, 60.3 % had received plasma exchange/plasma infusion, 59.5 % had a history of dialysis, and 19.6 % had received ≥1 kidney transplant. Overall, 305 patients (59.1 %) have received eculizumab.

Conclusions

As enrollment and follow-up proceed, the global aHUS Registry is expected to yield valuable baseline, natural history, medical outcomes, treatment effectiveness and safety data from a diverse population of patients with aHUS.

Trial registration

US National Institutes of Health www.ClinicalTrials.gov Identifier NCT01522183. Registered January 18, 2012.

Malignant Hypertension and Thrombotic Thrombocytopenic Purpura: False Friends

Patient: Male, 63

Final Diagnosis: Thrombotic thrombocyopenic purpura

Symptoms: —

Medication: —

Clinical Procedure: Plasmapharesis

Specialty: Hematology

Differentiating malignant hypertension-induced thrombotic microangiopathy from thrombotic thrombocytopenic purpura

OBJECTIVES

Malignant hypertension can cause thrombotic microangiopathy (TMA) and the overall presentation may mimic thrombotic thrombocytopenic purpura (TTP). This presents a dilemma of whether or not to initiate plasma exchange. The objective of the study was to determine the clinical and laboratory manifestations of malignant hypertension-induced TMA, and its outcomes.

METHODS

Using several search terms, we reviewed English language articles on malignant hypertension-induced TMA, indexed in MEDLINE by 31 December 2013. We also report a new case. All these cases were analyzed using descriptive statistics.

RESULTS

A total of 19 patients, with 10 males, had a median age of 38 years at diagnosis; 58% had a history of hypertension. Mean arterial pressure at presentation was 159 mmHg (range 123-190 mmHg). All had prominent renal dysfunction (mean creatinine of 5.2 mg/dl, range 1.7-13 mg/dl) but relatively modest thrombocytopenia (mean platelet count of 60 × 103/µl, range 12-131 × 10(3)/µl). Reported cases (n = 9) mostly had preserved ADAMTS-13 activity (mean 64%, range 18-96%). Following blood pressure control, the majority had improvement in presenting symptoms (100%) and platelet counts (84%); however, only 58% had significant improvement in creatinine. More than half (53%) needed hemodialysis. One patient died of cardiac arrest during pacemaker insertion.

CONCLUSION

Prior history of hypertension, high mean arterial pressure, significant renal impairment but relatively modest thrombocytopenia and lack of severe ADAMTS-13 deficiency (activity <10%) at diagnosis are clues to diagnose malignant hypertension-induced TMA. Patients with malignant hypertension respond well to antihypertensive agents and have favorable nonrenal outcomes.

Malignant hypertension with thrombotic microangiopathy and persistent acute kidney injury (AKI)

Two cases of malignant hypertension presenting with acute kidney injury, thrombocytopenia and hemolytic anemia are presented. In both patients a prolonged duration of renal replacement therapy was required. The plasma levels of ADAMTS13 enzyme were not helpful in delineating the precise pathogenesis in both cases, as the decrements were not severe. We discuss the clinic-pathologic correlation of the biopsy findings and persistence of AKI.

Hematologic manifestations of kidney disease

Physiologically, there is an intimate link between the kidney and the blood. Many of the kidney diseases are the result of alteration in the blood such as dysproteinemia, microangiopathic hemolytic anemia (MAHA), hemolysis, etc. On the other hand, the kidney is the organ responsible for the regulation of hematopoiesis. Renal dysfunction can lead to both anemia and polycythemia. In addition, recent understanding of the MAHA process reveals that the renal microvasculature plays a key role in the pathogenesis. Finally, the failure of the kidney to clear toxins from the body can result in alteration involving hemostasis, as well as leukocyte function and survival.

A case of lipoprotein glomerulopathy with thrombotic microangiopathy due to malignant hypertension

BACKGROUND

Lipoprotein glomerulopathy (LPG) is a rare inherited renal disease characterized by intraglomerular lipoprotein within the lumina of severely dilated glomerular capillaries. The common clinical presentation of LPG includes proteinuria or nephrotic syndrome. Hypertension and anemia were thought to be mild in LPG. Thrombotic microangiopathy (TMA) in LPG has not been previously reported. In this report, we present a patient with LPG that developed TMA. To the best of our knowledge, this is the first report of TMA in LPG.

CASE PRESENTATION

Four years ago (2005), a 19-year-old Chinese woman was diagnosed with nephrotic syndrome and provided prednisone treatment. A combination of prednisone and cyclophosphamide did not have any effect and was discontinued after six months. Although she was steroid-resistant, over the next subsequent three years, she maintained normal renal function without anemia and thrombocytopenia. In February 2009, she had a severe headache and blurry vision and presented at a local hospital with severe hypertension. Blood pressure was 220/160 mmHg. Laboratory data showed hemoglobin 3.8 g/dL; platelet counts 29 × 10(9)/L; urinary protein 7.90 g/d; total bilirubin 29.9 umol/L; indirect bilirubin 28.2 umol/L; LDH 1172 U/L; ALB 2.66 g/dL; urea nitrogen 52 mg/dL; serum creatinine 3.2 mg/dL; triglyceride 25  mg/dL; total cholesterol 273 mg/dL. ANA, ds-DNA, ANCA, anti-GBM antibody and anticardiolipin were all negative. A renal biopsy revealed LPG with TMA. Genetic evaluation showed the patient carried the APOE Kyoto mutation. Adequate control of blood pressure improved microangiopathic anemia and thrombocytopenia, however, renal function did not improve and she eventually developed uremia and became hemodialysis dependent.

CONCLUSION

We report on a rare case of TMA probably due to malignant hypertension in LPG. Early lipid-lowering and antihypertensive treatment may improve outcome. The pathophysiologic relationship between LPG and TMA should be investigated further.

Relationships between edema degree and clinical and biochemical parameters in posterior reversible encephalopathy syndrome: a preliminary study

The objective of the study was to investigate the associations between the degree of edema with the clinical and biochemical parameters such as serum lactate dehydrogenase (LDH), albumin (ALB) in posterior reversible encephalopathy syndrome (PRES) patients. Forty-nine patients with typical clinical symptoms and characteristic MR imaging findings of PRES were included in this study. Lactate dehydrogenase and ALB were analyzed with the immunoluminometric assays. Fluid-attenuated inversion recovery images were used to evaluate the distribution of the extent or severity of vasogenic edema by two observers. Correlation analysis between the scores of brain edema and the blood pressures, clinical conditions and biochemical parameters was performed. No significant difference of brain edema score was found between patients with eclampsia, chronic renal failure and other clinical condition (P > 0.05). Both mean arterial pressures and LDH level were moderately correlated with the scores of brain edema distribution (Spearman's ρ test, r = 0.405 and 0.497, respectively, P < 0.01). Serum ALB level was not correlated with the scores of brain edema distribution (P > 0.05). Larger and more diffuse lesions may be predicted by higher LDH level and blood pressure. The overall severity of the systemic process might be predicted by the degree of edema expression in PRES.

Cancer-related microangiopathic hemolytic anemia: clinical and laboratory features in 168 reported cases

Cancer-related microangiopathic hemolytic anemia (CR-MAHA) is a paraneoplastic syndrome characterized by Coombs-negative hemolytic anemia with schistocytes and thrombocytopenia. We reviewed and analyzed all cases of CR-MAHA reported since 1979 (the time of the last published review on this topic) according to predefined criteria. We found 154 cases associated with solid cancer and 14 with lymphoma. Among the solid cancers, gastric, breast, prostate, lung, and cancer of unknown primary (CUP) were most common; 91.8% of cancers were metastatic, and in 19.4% of solid cancers CR-MAHA did not occur until recurrence of cancer. Lymphoma cases included Hodgkin disease, angiotropic lymphoma, diffuse large cell lymphoma, and myeloma. Evaluation of the clinical and laboratory findings revealed that only a minority of cases presented with the features of thrombotic thrombocytopenic purpura (TTP) or atypical hemolytic uremic syndrome (aHUS), with the exception of prostate cancer, where aHUS was a common presentation. Compared to hereditary or immune TTP or aHUS, disseminated intravascular coagulation and pulmonary symptoms were more common in CR-MAHA. Plasma exchange or fresh frozen plasma was rarely effective except in prostate cancer patients with aHUS. CR-MAHA responded to antitumor therapy in many patients with gastric, breast, lung, and CUP cancers. These patients had a superior survival compared to patients without chemotherapy. Compared to the prognosis of patients with metastatic cancer without CR-MAHA, the prognosis of CR-MAHA patients was greatly inferior. There is evidence that some cases of CR-MAHA in lymphoma are immune mediated.

Malignant hypertension with reversible brainstem hypertensive encephalopathy and thrombotic microangiopathy

A 42-year-old woman presented with headache and nausea. Severe hypertension, renal dysfunction, thrombocytopenia, and anemia were present. A magnetic resonance imaging (MRI) scan of her head revealed widespread hyperintense lesions located in the brainstem and cerebellum on T2-weighted and fluid-attenuated inversion recovery imaging. Hypertensive encephalopathy was suspected, and antihypertensive therapy was started. A second MRI of the patient's head on day 12 of hospitalization revealed that the hyperintensities in the brainstem and cerebellum had almost disappeared, and that thrombocytopenia, anemia, and renal dysfunction had also gradually improved. Test results led to a diagnosis of malignant hypertension. This patient was regarded as suffering from malignant hypertension with reversible brainstem hypertensive encephalopathy (RBHE) and thrombotic microangiopathy (TMA). RBHE and TMA are known to occur as complications of malignant hypertension, but there has been no previous report of them occurring simultaneously. RBHE and TMA related to malignant hypertension are both conditions that can be improved by the rapid institution of antihypertensive therapy, and as such, early diagnosis and treatment are important. When treating patients with malignant hypertension, the possibility that it may be complicated by both RBHE and TMA must be kept in mind.

Thrombotic microangiopathy: a role for magnesium?

Despite advances in more recent years, the pathophysiology and especially treatment modalities of thrombotic microangiopathy (TMA) largely remain enigmatic. Disruption of endothelial homeostasis plays an essential role in TMA. Considering the proven causal association between magnesium and both endothelial function and platelet aggregability, we speculate that a magnesium deficit could influence the course of TMA and the related haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura. A predisposition towards TMA is seen in many conditions with both extracellular and intracellular magnesium deficiency. We propose a rationale for magnesium supplementation in TMA, in analogy with its evidence-based therapeutic application in pre-eclampsia and suggest, based on theoretical grounds, that it might attenuate the development of TMA, minimise its severity and prevent its recurrence. This is based on several lines of evidence from both in vitro and in vivo data showing dose-dependent effects of magnesium supplementation on nitric oxide production, platelet aggregability and inflammation. Our hypothesis, which is further amenable to assessment in animal models before therapeutic applications in humans are implemented, could be explored both in vitro and in vivo to decipher the potential role of magnesium deficit in TMA and of the effects of its supplementation.