Outcome 10 years after Shiga toxin-producing E. coli (STEC)-associated hemolytic uremic syndrome: importance of long-term follow-up

BACKGROUND

Hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury in children. HUS is known as an acute disease followed by complete recovery, but patients may present with kidney abnormalities after long periods of time. This study evaluates the long-term outcome of Shiga toxin-producing Escherichia coli-associated HUS (STEC-HUS) in pediatric patients, 10 years after the acute phase of disease to identify risk factors for long-term sequelae.

METHODS

Over a 6-year period, 619 patients under 18 years of age with HUS (490 STEC-positive, 79%) were registered in Austria and Germany. Long-term follow-up data of 138 STEC-HUS-patients were available after 10 years for analysis.

RESULTS

A total of 66% (n = 91, 95% CI 0.57-0.73) of patients fully recovered showing no sequelae after 10 years. An additional 34% (n = 47, 95% CI 0.27-0.43) presented either with decreased glomerular filtration rate (24%), proteinuria (23%), hypertension (17%), or neurological symptoms (3%). Thirty had sequelae 1 year after STEC-HUS, and the rest presented abnormalities unprecedented at the 2-year (n = 2), 3-year (n = 3), 5-year (n = 3), or 10-year (n = 9) follow-up. A total of 17 patients (36.2%) without kidney abnormalities at the 1-year follow-up presented with either proteinuria, hypertension, or decreased eGFR in subsequent follow-up visits. Patients needing extracorporeal treatments during the acute phase were at higher risk of presenting symptoms after 10 years (p < 0.05).

CONCLUSIONS

Patients with STEC-HUS should undergo regular follow-up, for a minimum of 10 years following their index presentation, due to the risk of long-term sequelae of their disease. An initial critical illness, marked by need of kidney replacement therapy or plasma treatment may help predict poor long-term outcome.

Early relapse rate determines further relapse risk: results of a 5-year follow-up study on pediatric CFH-Ab HUS

BACKGROUND

The complement factor H antibody (CFH-Ab)-associated hemolytic uremic syndrome (HUS) forms a distinct subgroup within the complement-mediated HUS disease spectrum. The autoimmune nature of this HUS subgroup implies the potential benefit of a targeted immunosuppressive therapy. Data on long-term outcome are scarce.

METHODS

This observational study evaluates the clinical outcome of 19 pediatric CFH-Ab HUS patients from disease onset until their 5-year follow-up.

RESULTS

All but one relapse occurred during the first 2 years, and patients who had no relapse within the first 6 months were relapse-free until the end of the observation period. Kidney function at disease onset determines long-term kidney function: all individuals with normal kidney function at disease onset had normal kidney function after 5 years, and all patients with reduced kidney function at onset had impaired kidney function at the last follow-up. Level of CFH-Ab titer at disease onset was not correlated with a higher risk of recurrences or worse long-term outcome after 5 years. Resolution of CFH-Ab titers after 5 years was common.

CONCLUSIONS

CFH-Ab HUS patients have a varied overall long-term course. Early relapses are common, making close surveillance during the first years essential, regardless of the initial CFH-Ab titer.

[Sarcoidosis : Dermatological view of a rare multisystem disease]

Sarcoidosis is a rare multisystem inflammatory disease of largely unknown etiology. While pulmonary sarcoidosis is the most abundant organ manifestation, involvement of the skin that occurs in up to 30% of patients is the most common extrapulmonary presentation of the disease. Dermatologists therefore play an important role not only for establishing the diagnosis and delineating it from potential differential diagnoses but also for the interdisciplinary care of the patient. The clinical presentation of skin sarcoidosis is manifold, which occasionally aggravates making the final diagnosis. Specific skin lesions (with granulomas) and nonspecific skin manifestations (without granulomas) can be differentiated. Since a variety of organ systems can be affected, multidisciplinary cooperation is mandatory. Therapy of sarcoidosis is difficult; evidence-based studies and therapy guidelines are widely lacking. Our review intends to outline the characteristic clinical presentations of cutaneous sarcoidosis, describe the diagnostic approach and how to assure or exclude extracutaneous manifestations of sarcoidosis, and suggest a therapy algorithm for the treatment of skin sarcoidosis.

Die Sarkoidose aus dermatologischer Perspektive

Die Sarkoidose ist eine seltene Multisystemerkrankung, welche durch nicht-verkäsende Granulome charakterisiert ist, die sich an verschiedenen Organen manifestieren können. Die Pathogenese der Sarkoidose ist nicht vollständig geklärt, neben genetischen Faktoren spielen auch infektiöse Triggerfaktoren sowie Umwelteinflüsse eine Rolle. Die Lunge ist bei über 90 % der Patienten betroffen und damit das am häufigsten involvierte Organ. Es folgt die Haut, die bei bis zu einem Drittel der Sarkoidose-Patienten Auffälligkeiten aufweist, welche anderen Organbeteiligungen häufig vorausgehen. Es ist daher wichtig, die Sarkoidose der Haut frühzeitig zu diagnostizieren, damit eine symptomorientierte Durchuntersuchung und Therapie in die Wege geleitet werden können. Letztere gestaltet sich oft schwierig, da evidenzbasierte Therapieempfehlungen weitgehend fehlen.

In dieser Übersichtarbeit werden die dermatologische Vielgestaltigkeit der Erkrankung, die empfohlenen fachspezifischen und fachübergreifenden Untersuchungen sowie die Therapiemöglichkeiten vorgestellt und diskutiert.

Successful management of recurrent focal segmental glomerulosclerosis

Primary focal segmental glomerulosclerosis (FSGS) recurs in up to 55% of patients after kidney transplantation. Herein we report the successful management of recurrent FSGS. A 5-year-old boy with primary FSGS received a deceased donor renal transplant. Immediate and fulminant recurrence of FSGS caused anuric graft failure that was resistant to plasmapheresis and rituximab. After exclusion of structural or immunologic damage to the kidney by repeated biopsies, the allograft was retrieved from the first recipient on day 27 and transplanted into a 52-year-old second recipient who had vascular nephropathy. Immediately after retransplantation, the allograft regained function with excellent graft function persistent now at 3 years after transplant. After 2 years on hemodialysis, the boy was listed for kidney retransplantation. To prevent FSGS recurrence, pretreatment with ofatumumab was performed. Nephrotic range proteinuria still occurred after the second transplantation, which responded, however, to daily plasma exchange in combination with ofatumumab. At 8 months after kidney retransplantation graft function is good. The clinical course supports the hypothesis of a circulating permeability factor in the pathogenesis of FSGS. Successful ofatumumab pretreatment implicates a key role of B cells. Herein we provide a description of successful management of kidney failure by FSGS, carefully avoiding waste of organs.

Deficiency of the sphingosine-1-phosphate lyase SGPL1 is associated with congenital nephrotic syndrome and congenital adrenal calcifications

We identified two unrelated consanguineous families with three children affected by the rare association of congenital nephrotic syndrome (CNS) diagnosed in the first days of life, of hypogonadism, and of prenatally detected adrenal calcifications, associated with congenital adrenal insufficiency in one case. Using exome sequencing and targeted Sanger sequencing, two homozygous truncating mutations, c.1513C>T (p.Arg505*) and c.934delC (p.Leu312Phefs*30), were identified in SGPL1-encoding sphingosine-1-phosphate (S1P) lyase 1. SGPL1 catalyzes the irreversible degradation of endogenous and dietary S1P, the final step of sphingolipid catabolism, and of other phosphorylated long-chain bases. S1P is an intracellular and extracellular signaling molecule involved in angiogenesis, vascular maturation, and immunity. The levels of SGPL1 substrates, S1P, and sphingosine were markedly increased in the patients' blood and fibroblasts, as determined by liquid chromatography-tandem mass spectrometry. Vascular alterations were present in a patient's renal biopsy, in line with changes seen in Sgpl1 knockout mice that are compatible with a developmental defect in vascular maturation. In conclusion, loss of SGPL1 function is associated with CNS, adrenal calcifications, and hypogonadism.

Keratinocytes and neutrophils are important sources of proinflammatory molecules in hidradenitis suppurativa

BACKGROUND

The pathogenesis of the chronic inflammatory skin disease hidradenitis suppurativa (HS, also known as acne inversa) involves epidermal alterations such as psoriasiform epidermal hyperplasia and keratin plugging. Keratinocytes are an important source of proinflammatory molecules in inflammatory skin diseases and can be stimulated by interleukin (IL)-17(+) cells.

OBJECTIVES

To explore the possible role of the epithelium in the pathogenesis of HS.

METHODS

We performed immunohistochemical stainings and Western blot experiments to investigate the localization and expression of inflammation-associated molecules, including the cytokine IL-17, components of the inflammasome including caspase-1, and the endogenous danger-associated molecular pattern molecules S100A8 and S100A9 (calprotectin). To examine a possible effect of upregulated proinflammatory cytokines on the inflammatory infiltrate, differences in the cellular composition of perifollicular and deep dermal infiltrates were analysed.

RESULTS

The number of IL-17(+) cells is increased in lesional and perilesional HS skin. The epidermis produces proinflammatory molecules and shows an upregulated expression of components of the NLRP3 inflammasome, activated caspase-1 and expression of S100A8/S100A9. Additionally, the course of the inflammatory process in HS involves influx of innate immune cells, particularly IL-17-expressing neutrophils.

CONCLUSIONS

IL-17-producing cells are present in lesional and perilesional HS skin and may contribute to the initiation of inflammatory processes. Furthermore, the epidermis is a source of proinflammatory cytokines, shows inflammasome activation and expresses S100A8/S100A9, thereby possibly contributing to the propagation of inflammation. A massive influx of IL-17-expressing neutrophils is observed in the deep infiltrate.

Decreased Urinary Sodium-to-urinary Creatinine Ratio Identifies Sodium Depletion in Pediatric Acute Gastroenteritis

In acute gastroenteritis (AG) fecal losses may cause depletion of sodium (NaD) which may not be recognized because of normal plasma Na (pNa) concentrations. We studied the incidence of this state of normonatremic sodium depletion (NNaD) and the suitability of the urinary Na/urinary creatinine ratio (uNa/uCr) for diagnosing NNaD.

PATIENTS

16 AG- and 16 healthy control children aged 0.8-15.0 years.

METHODS

Prospective cross sectional pilot study. Measurements of Na, K and creatinine in plasma (p) and urine (u). Calculation of uNa/uCr Ratio, fractional excretion of Na (FENa) and uNa/uK ratio as the hitherto best known parameters of prerenal Na depletion, respectively.

RESULTS

pNa concentrations were normal in 15/16 AG patients (93.8%) with only one subnormal value of 133 mmol/L, and a mean value of 137.9±2.3 mmol/L not different from the normal control group (139.4±2.2 mmol/L). Also, mean uNa concentrations and uNa/uK ratios did not differ between both groups. However, uNa/uCr ratios were below normal in 13/16 AG children (81.3%) but normal in all healthy controls with a significantly lower mean value in the AG group (12.6±8.8 vs. 31.2±8.3 mmol/mmol; p<0.0001). Similarly, 14/16 AG patients (87.5%) had a decreased FENa<0.5% with a mean FENa value significantly lower than in controls (0.36±0.28% vs. 0.95±0.26%, p<0.0001). The good agreement between FENa and uNa/uCr results was also reflected by a high correlation coefficient of r=0.9333.

CONCLUSIONS

The majority of AG patients was found to have NNaD as determined by uNa/uCr and FENa. Calculation of uNa/uCr may be useful for diagnosing NNaD in AG.

Successful living-related renal transplantation in a patient with factor H antibody-associated atypical hemolytic uremic syndrome

CFH-Ab-associated aHUS requires different diagnostic and therapeutic approaches and then the genetically defined aHUS forms. The risk of post-transplant recurrence with graft dysfunction in CFH-Ab aHUS is not well documented. It is suggested that recurrence can be expected if a significant CFH-Ab load persists at the time of transplantation. A pretransplant procedure to reduce CFH-Ab titer seems reasonable, but accurate recommendations are lacking. Whether further prophylactic interventions after transplantation are necessary has to be decided on an individual basis. We report the case of a late diagnosed CFH-Ab HUS with initial ESRD and a successful living-related renal transplantation over a post-transplant period of four and a half years on the basis of a prophylactic pretransplant IVIG admission.

Severe visual loss caused by unrecognized malignant hypertension in a 15-year-old girl

A 15-year-old girl presented with acute bilateral loss of central visual acuity due to hypertensive retinopathy level IV. She was found to have unrecognized malignant arterial hypertension associated with end-stage renal failure. At the time of diagnosis she also had severe left ventricular hypertrophy (LVH). Hypertension was successfully treated with combined anti-hypertensive therapy, but renal function did not recover. The patient underwent successful kidney transplant 4 months later and over a period of 20 months hypertensive retinopathy and LVH gradually resolved. This report emphasizes the importance of routine measurement of blood pressure and describes the possible consequences of unrecognized arterial hypertension in children. Early diagnosis and appropriate treatment are necessary to avoid development and progression of target organ damage and promote better long-term cardiovascular prognosis.

Kawasaki disease in children and adolescents: clinical data of Kawasaki patients in a western region (Tyrol) of Austria from 2003-2012

BACKGROUND

Kawasaki disease (KD) is a rare vasculitis seen predominantly in children. In developing countries, it is the leading cause of childhood-acquired heart disease. Besides a case report from 1981 there have been no data published dealing with the epidemiology and clinical aspects of KD in Austria.

METHODS

The purpose of the present study was to investigate the clinical spectrum of KD in a geographically determined cohort of infants, children, and adolescents that were diagnosed and treated at the University Hospital of Innsbruck from 2003-2012.

RESULTS

Thirty-two patients were included in the study with a median age of 32.96 months (2-192). 59.4% of the patients were aged between six months and four years. The male-to-female ratio was 1:1.13. Clinical examination revealed non-purulent conjunctivitis and exanthema as the most common symptoms (84.4%). 75% showed oropharyngeal changes, 21.9% had gastrointestinal complaints such as diarrhoe, stomachache or vomiting prior to diagnosis. One third of the patients were admitted with a preliminary diagnosis, whereas 78.1% were pre-treated with antibiotics. The median fever duration at the time of presentation was estimated with 4.96 days (1-14), at time of diagnosis 6.76 days (3-15).75% were diagnosed with complete KD, and 25% with an incomplete form of the disease. There was no significant difference in the duration of fever neither between complete and incomplete KD, nor between the different age groups. Typical laboratory findings included increased C-reactive protein (CRP) (80.6%) and erythrocyte sedimentation rate (ESR) (96%),leukocytosis (48.4%) and thrombocytosis (40.6%) without any significant quantitative difference between complete and incomplete KD. Coronary complications could be observed in six patients: one with a coronary aneurysm and five with tubular dilatation of the coronary arteries. Our patient cohort represents the age distribution as described in literature and emphasizes that KD could affect persons of any age. The frequency of occurrence of the clinical symptoms differs from previous reports - in our study, we predominantly observed non-purulent conjunctivitis and exanthema.

CONCLUSION

KD should always be considered as a differential diagnosis in a child with fever of unknown origin, as treatment can significantly decrease the frequency of coronary complications.

Diagnosis and treatment of the hemolytic uremic syndrome disease spectrum in developing regions

There has been rapid progress in the understanding of the pathophysiology of the hemolytic uremic syndrome (HUS) disease spectrum; thus, complex diagnostic and therapeutic requirements have emerged in parallel. Current recommendations for diagnosis and therapy were rapidly adapted from the prior skilled scientific groundwork. However, such recommendations can be realized only when highly specialized laboratories and sufficient financial resources are available. Thus, many recommendations are not feasible for patients living and working in developing countries. More than one-third of the world's population has no access to essential drugs and more than half of this group lives in the poorest regions of Africa and Asia. From this perspective, distinct initial diagnostic and therapeutic recommendations, as well as international cooperations are needed to complete proper diagnostic work-ups in a stringent and cost-efficient manner and to enable patients to be adequately treated with available resources. However, while costs for complement-targeted drugs remain tremendously high, state-of-the-art treatment options remain unavailable for the vast majority of patients in developing areas.

Complement factor H-antibody-associated hemolytic uremic syndrome: pathogenesis, clinical presentation, and treatment

The presence of circulating autoantibodies, primarily to complement factor H antibodies (CFH-Abs) in plasma characterizes the autoimmune form of atypical hemolytic uremic syndrome (aHUS). This acquired form of aHUS defines a distinct subgroup of aHUS patients, which requires diagnostic and treatment approaches in part different from those of the genetically defined forms. The mechanisms leading to CFH-Ab production and disease onset are not completely understood, but CFH-Ab HUS seems to be secondary to a combination of genetic predisposition and environmental factors. Early diagnosis of this specific aHUS entity is important, as prompt induction of plasma exchange and concomitant immunosuppression leads to a favorable outcome. Nevertheless, information on clinical features and outcome in children is limited. Here, we review the literature on the biological and clinical features of CFH-Ab HUS and discuss therapeutic options.

Extra-renal manifestations of complement-mediated thrombotic microangiopathies

Thrombotic microangiopathies (TMA) are rare but severe disorders, characterized by endothelial cell activation and thrombus formation leading to hemolytic anemia, thrombocytopenia, and organ failure. Complement over activation in combination with defects in its regulation is described in an increasing number of TMA and if primary for the disease denominated as atypical hemolytic-uremic syndrome. Although TMA predominantly affects the renal microvasculature, extra-renal manifestations are observed in 20% of patients including involvement of the central nerve system, cardiovascular system, lungs, skin, skeletal muscle, and gastrointestinal tract. Prompt diagnosis and treatment initiation are therefore crucial for the prognosis of disease acute phase and the long-term outcome. This review summarizes the available evidence on extra-renal TMA manifestations and discusses the role of acute and chronic complement activation by highlighting its complex interaction with inflammation, coagulation, and endothelial homeostasis.

Complement factor H-related protein 1 deficiency and factor H antibodies in pediatric patients with atypical hemolytic uremic syndrome

BACKGROUND AND OBJECTIVES

This study evaluated the relevance of complement factor H (CFH)-related protein (CFHR) 1 deficiency in pediatric patients with atypical hemolytic uremic syndrome (aHUS) by evaluating both the frequency of deletions in CFHR1 and the presence of complement factor H (CFH) antibodies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A total of 116 patients (mainly from central Europe) and 118 healthy blood donors were included from 2001 to 2012. The presence of CFHR1 gene deletions was determined in 90 pediatric patients with aHUS and 118 controls by an easy, fast, and cheap PCR assay; 100 patients with aHUS and 42 controls were tested for CFH antibodies by ELISA. Questionnaires were administered to evaluate the clinical and laboratory data.

RESULTS

Homozygous deletion in CFHR1 was detected in 32% of the patients with aHUS tested, compared with 2.5% of controls (P<0.001). CFH antibodies were present in 25% of the patients and none of the controls. CFH antibodies were detected in 82% of patients with homozygous CFHR1 gene deletion and in 6% of patients without. CFH antibody-positive patients with aHUS showed a significantly lower platelet nadir at disease onset and significantly less frequent involvement of the central nervous system than did antibody-negative patients. Antibody-positive patients also received plasma therapy more often.

CONCLUSION

Homozygous deletion in CFHR1 is strongly associated with occurrence of CFH antibodies in pediatric patients with aHUS. However, despite this apparent genetic disease predisposition, it cannot be considered an exclusive cause for aHUS. Initial presentation of Shiga toxin-negative HUS with severe thrombocytopenia and no central nervous system complications in pediatric patients is especially suspicious for CFH antibody aHUS.

Analysis of the classical, alternative, and mannose binding lectin pathway of the complement system in the pathogenesis of oligoarticular juvenile idiopathic arthritis

The complement system plays a role in the pathogenesis of some autoimmunopathies. This longitudinal study evaluates the contribution of the complement system in the pathogenesis of oligoarticular juvenile idiopathic arthritis (JIA). Serum of the peripheral blood and the synovial fluid were investigated for the activity of the classical (CP), the mannose binding lectin (MBL), and the alternative pathway (AP). A total of 12 samples from peripheral blood (PB) and two samples from synovial fluid (SF) of girls with oligoarticular JIA were investigated in a longitudinal observation from the time point of the diagnosis of JIA. The differences between the complement activity in the PB and in the SF were extremely statistically significant (CP and MBL: P < 0.0001; AP: < 0.0087). The activity of the CP and the MBL pathway was reduced. The AP is the main contributor in the pathogenesis of oligoarticular JIA. Anti-C5 therapy may be an option to avoid the creation of the membrane attack complex.

A large family with a gain-of-function mutation of complement C3 predisposing to atypical hemolytic uremic syndrome, microhematuria, hypertension and chronic renal failure

BACKGROUND AND OBJECTIVES

Atypical hemolytic uremic syndrome (aHUS) is associated with mutations in genes encoding complement-regulatory proteins factor H, I and B and membrane cofactor protein. Recently, heterozygous gain-of-function mutations in the complement C3 gene have been found in patients with aHUS.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A large family with a C3 R570Q mutation is described. Clinical and laboratory findings of carriers of the mutation and unaffected family members are reported.

RESULTS

The index patient suffered from recurrent aHUS at age 22 and developed end-stage renal failure. Of 24 family members, nine harbored the C3 R570Q mutation. Carriers showed reduced or borderline C3 levels. Arterial hypertension was found in six family members, microhematuria in five and chronic kidney disease stage 3 in two elderly carrier patients. Despite marked consumption of C3, serum terminal complement complex levels were not elevated in carriers compared with other family members.

CONCLUSIONS

The penetrance of the C3 R570Q mutation to induce aHUS is incomplete and lower compared with mutations in other genes predisposing to the disease. The mutation is possibly also associated with hypertension, hematuria and chronic kidney disease, all of which may represent consequences of long-term complement activation in the renal vasculature.