Outcomes of Adult Patients With Sickle Cell Disease Admitted to the ICU: A Case Series*

Sputum interleukin-6 level as a marker of severity during acute chest syndrome in children with sickle cell disease

Acute chest syndrome (ACS) is a leading cause of morbimortality in sickle cell disease (SCD). In this prospective observational study, we investigated sputum interleukin-6 (IL-6) level as an ACS severity marker during 30 ACS episodes in 26 SCD children. Sputum IL-6 levels measured within the first 72 h of hospitalisation for ACS were significantly higher in patients with oxygen requirement ≥2 L/min, ventilation (invasive and/or non-invasive) length ≥5 days, bilateral and/or extensive opacities on chest X-ray or erythrocytapheresis requirement. Sputum IL-6 could serve as an ACS severity marker to help identify patients requiring targeted anti-inflammatory treatments such as tocilizumab.

Factors associated with adverse outcome among children with sickle cell disease admitted to the pediatric intensive care unit: an observational cohort

BACKGROUND

Sickle cell disease (SCD) is one of the most frequent inherited diseases in the world. Over the last decades, in high-income countries, an important decrease in mortality have been observed due to the improvement of care. However, children with SCD can become critically ill and require admission in Pediatric Intensive Care Units (PICU). The purpose of this study was to describe the epidemiology of children with SCD admitted to PICU for acute crisis and to identify factors associated with adverse outcome (AO).

METHODS

We conducted a retrospective study in a Tertiary Hospital in France including all consecutive children with SCD admitted to PICU between January 1st, 2009 and December 31, 2019. We collected baseline patient's characteristics, clinical and biological data as well as treatments and life sustaining therapies used in the PICU. Patients were defined as experiencing AO in case of death during stay and/or need for invasive mechanical ventilation (MV) and/or for non-invasive ventilation (NIV) for more than 3 days and/or need for vasopressors and/or need for renal replacement therapy.

RESULTS

We included 579 admissions in 395 patients, mainly of SS genotype (90%) with a median age of 9.2 years [5.5-13.4] and a median baseline hemoglobin of 8.0 g/dl (7.5-8.8). The two main reasons for admission were acute chest syndrome (ACS) (n = 331, 57%) and vaso-occlusive crisis refractory to first line therapy (n = 99, 17%). Half of patients required NIV and 47 (8%) required MV. The overall length of stay was 3 days [1-4] and seven (1%) patients died during PICU stay.There was a total of 113 (20%) admissions with AO and on multivariable analysis, baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were associated with AO. There was no difference in the proportion of hydroxyurea treatment or exchange transfusion program between patients with AO and the other patients.

CONCLUSIONS

Baseline hemoglobin < 8 g/dL, history of bronchial obstruction and admission for ACS were the strongest risk factors for severe evolution in SCD children admitted to PICU. These factors could be taken into consideration when choosing the adequate therapeutic options.

Predictors of Intensive Care Admission Among Adult Patients with Sickle Cell Disease in Eastern Province of Saudi Arabia

Purpose

Sickle cell disease (SCD) comprises a complex group of hematologic disorders that are collectively the most common monogenic disorder and are associated with increased risk of intensive care unit admission (ICU). The purpose of this study is to investigate factors that predict admission of adult patients with SCD to the ICU.

Patients and Methods

This was a cross-sectional study that enrolled adult patients with SCD from Saudi Arabia.

Results

A total of 107 patients with SCD, with a median age 31.9±12.1 years, were evaluated retrospectively. Regarding predictors of ICU admission, patients who indicated a history of blood transfusions were at 8.047-fold higher risk of ICU admission (OR=8.047; 95% CI=2.392-27.07; p=0.001). Patients who started hydroxyurea were at least 3.071 times more likely to be admitted than those who did not (OR=3.071; 95% CI=1.164-8.104; p=0.023). We also observed three or more hospitalizations per year to be associated with increased risk of ICU admission (OR=3.393; 95% CI=1.285-8.960; p=0.014), with those making 3 to 5 visits annually having at least 10.4 times higher risk (OR=10.38; 95% CI=10.098-98.19; p=0.041) and those with 6 to 10 ER admissions having 18 times higher risk (OR=18.00; 95% CI=2.149-150.8; p=0.008). Finally, patients with high WBC were predicted to have at least 3.34 times higher risk of ICU admission (OR=3.337; 95% CI=1.131-9.846; p=0.029).

Conclusion

SCD is a multi-systemic disease associated with increased morbidity and mortality. Recognition of high-risk features in patients helps to eliminate subjectivity in ICU referral decision. Frequent hospitalization and emergency visits, multiple blood transfusions, and elevated white blood cell count were significantly associated with a higher rate of ICU admission despite hydroxyurea usage.

Acute chest syndrome in adult patients with sickle cell disease: The relationship with the time to onset after hospital admission

Data on acute chest syndrome (ACS) in adult sickle cell disease patients are scarce. In this study, we describe 105 consecutive ACS episodes in 81 adult patients during a 32-month period and compare the characteristics as a function of the time to onset after hospital admission for a vaso-occlusive crisis (VOC), that is early-onset episodes (time to onset ≤24 h, 42%) versus secondary episodes (>24 h, 58%; median [interquartile range] time to onset: 2 [2-3] days). The median age was 27 [22-34] years, 89% of the patients had an S/S or S/β⁰ -thalassaemia genotype; 81% of the patients had a history of ACS (median: 3 [2-5] per patient), only 61% were taking a disease-modifying treatment at the time of the ACS. Fever and chest pain were noted in respectively 54% and 73% of the episodes. Crackles (64%) and bronchial breathing (32%) were the main abnormal auscultatory findings. A positive microbiological test was found for 20% of episodes. Fifty percent of the episodes required a blood transfusion; ICU transfer and mortality rates were respectively 29% and 1%. Secondary and early-onset forms of ACS did not differ significantly. Disease-modifying treatments should be revaluated after each ACS episode because the recurrence rate is high.

[Hemolytic anemia in emergency and intensive care medicine]

Hemolytic anemia (HA) is caused by premature destruction or degradation of red blood cells (RBC). Low hemoglobin, suppressed haptoglobin, reticulocytosis as well as an elevation of lactate dehydrogenase and bilirubin are common laboratory findings in HA. Intracorpuscular HA due to defects of the RBC themselves are distinguished from extracorpuscular HA due to external factors. Severity of symptoms such as fatigue and dyspnea depend on the degree of anemia. For optimal treatment of HA, a detailed evaluation of the patient history (including hereditary RBC defects, B symptoms and travel history) is necessary. Additional diagnostics (hematological diagnostics, infectious disease diagnostics, immunological diagnostics, computed tomography [CT] scan) should be performed according to the patient's individual requirements. Treatment of HA depends on the etiology. If HA is immune-mediated, immunosuppressive therapy is indicated, whereas HA due to infections usually improves after adequate anti-infective therapy. Anti-infective therapy should also be considered in patients with sickle cell disease who present with severe HA. In general, HA can be treated effectively in most cases.

[Acute chest syndrome in adult sickle cell patients]

Sickle cell disease is a frequent genetic condition, due to a mutation of the β-globin gene, leading to the production of an abnormal S hemoglobin and characterized by multiple vaso-occlusive events. The acute chest syndrome is a severe complication associated with a significant disability and mortality. It is defined by the association of one or more clinical respiratory manifestations and a new infiltrate on lung imaging. Its pathophysiology is complex and implies vaso-occlusive phenomena (pulmonary vascular thrombosis, fat embolism), infection, and alveolar hypoventilation. S/S or S/β⁰-thalassemia genotype, a history of vaso-occlusive crisis or acute chest syndrome, a low F hemoglobin level (<5%), a high steady-state hemoglobin level (> 10 g/dL), or a high steady-state leukocytosis (>10 G/L) are the main risk factors. Febrile chest pain, dyspnea, sometimes cough with expectorations are its main clinical manifestations, and bi-basal crackles are found at auscultation. Inferior alveolar opacities with or without pleural effusions are identified on chest X-ray or CT-scan. Management of the acute chest syndrome should be prompt and implies, besides the recognition of severity signs, a multimodal analgesia, oxygen supplementation, sometimes a parenteral antibiotic treatment and the frequent use of blood transfusions especially in the most severe cases. Prevention is important and includes a regular monitoring of hospitalized patients and the use of incentive spirometry.

Phenotypes of sickle cell intensive care admissions: an unsupervised machine learning approach in a single-center retrospective cohort

Sickle cell disease (SCD) is associated with multiple known complications and increased mortality. This study aims to further understand the profile of intensive care unit (ICU) admissions of SCD patients. In this single-center retrospective cohort (approval number 0926-11), we evaluated SCD-related ICU admissions at our hospital in São Paulo, Brazil. Admissions were clustered using clinical data and organ dysfunction at ICU admission. A hierarchical clustering method was used to distinguish phenotypes. From 140 admissions obtained, 125 were included. The mean age was 30 years, 48% were male, and SS genotype was predominant (71.2%). Non-surgical causes of admissions accounted for 85.6% (n = 107). The mean Sequential Organ Failure Assessment score (SOFA) was 4 (IQR 2-7). Vasopressors were required by 12% and mechanical ventilation by 17.6%. After analysis of the average silhouette width, the optimal number of clusters was 3: cluster 1 (n = 69), cluster 2 (n = 25), cluster 3 (n = 31). Cluster 1 had a mean age of 29 years, 87% of SS genotype, and mean SOFA of 4. Cluster 2 had a mean age of 37 years, 80% of SS genotype, and mean SOFA of 8. Cluster 3 had a mean age of 26 years, 29% of SS genotype, and mean SOFA of 3. The need for mechanical ventilation was 11.6%, 44%, and 9.7%, respectively. Mortality was significantly higher in cluster 2 (44%, p = 0.012). This cohort of critical SCD admissions suggested the presence of three different profiles. This can be informative in the ICU setting to identify SCD patients at higher risk of worse outcomes.

Sickle Cell Disease and Kidney

Sickle cell disease causes several kidney manifestations. They include defects in urine concentration, impaired handling of potassium and hydrogen ion, albuminuria, acute kidney injury, and chronic kidney disease to name a few. Glomerular hyperfiltration, tubular hyperfunctioning, endothelial damage from repeated sickling and vaso-occlusive episodes, and iron-induced proinflammatory changes in the glomerular mesangium and tubulointerstitium are some of the mechanisms of kidney damage. Albuminuria is one of the most and common clinical features of kidney disease and progresses with age. Kidney disease in patients with sickle cell is associated with increased mortality. Annual screening for proteinuria starting at age 10 years and limiting the use of nonsteroidal anti-inflammatory agents and the use of angiotensin-converting enzyme inhibitors may help in early detection and delaying the progression of kidney disease. Adequate hydration, angiotensin-converting enzyme inhibitors, and adequate control of sickle cell are the main stay of treatment for albuminuria. The hemoglobin goal for patients with sickle cell nephropathy is lesser (10 g/dL) than that for patients with chronic kidney disease due to other causes given that a higher hemoglobin level increases viscosity and the risk of precipitating vaso-occlusive episodes. A multidisciplinary approach is recommended for managing patients with sickle cell and kidney diseases.

Endothelial dysfunction and hypercoagulability in severe sickle-cell acute chest syndrome

Rationale

Acute pulmonary hypertension (PH) may develop during sickle-cell acute chest syndrome (ACS), and is associated with an increased mortality. Its mechanisms remain poorly known. We questioned whether there is endothelial dysfunction and hypercoagulability in severe ACS, with and without acute PH.

Methods

In a prospective monocentre cohort follow-up study, all sickle-cell adult patients with ACS admitted to the intensive care unit underwent transthoracic echocardiography and measurement of biomarkers of coagulation, endothelial activation and platelet and erythrocyte activation. Acute PH was defined as a high echocardiographic probability of PH. The biological profiles of sickle-cell patients were analysed at the time of ACS, contrasting with the existence of acute PH, and compared with steady-state and with non-sickle-cell controls (healthy subjects and community-acquired pneumonia).

Results

Most patients (36 patients with 39 ACS episodes; 23 males; median age 27 years) had thoracic pain, dyspnoea and computed tomography scan lung consolidation. Acute PH was diagnosed in seven (19%) patients. Erythrocyte- and platelet-derived microparticles and the pro-coagulant activity of microparticles were higher in ACS patients with acute PH, compared with their counterparts. Compared with healthy controls, ACS patients had higher levels of tissue factor, fibrin monomers, D-dimer, release of pro-coagulant microparticles and erythrocyte- and platelet-derived microparticles. Compared with community-acquired pneumonia patients, ACS patients had increased levels of fibrin monomers and erythrocyte- and platelet-derived microparticles.

Conclusions

Severe ACS is characterised by endothelial dysfunction and hypercoagulability, with a marked pro-coagulant profile in cases of associated PH.

Severe sickle-cell acute chest syndrome is associated with an activation of the pulmonary vascular endothelium and of coagulation, with higher levels of pro-coagulant microparticles in cases of associated acute pulmonary hypertensionhttps://bit.ly/3sjkaYy

Nationwide retrospective study of critically ill adults with sickle cell disease in France

Little is known about patients with sickle cell disease (SCD) who require intensive care unit (ICU) admission. The goals of this study were to assess outcomes in patients admitted to the ICU for acute complications of SCD and to identify factors associated with adverse outcomes. This multicenter retrospective study included consecutive adults with SCD admitted to one of 17 participating ICUs. An adverse outcome was defined as death or a need for life-sustaining therapies (non-invasive or invasive ventilation, vasoactive drugs, renal replacement therapy, and/or extracorporeal membrane oxygenation). Factors associated with adverse outcomes were identified by mixed multivariable logistic regression. We included 488 patients admitted in 2015-2017. The main reasons for ICU admission were acute chest syndrome (47.5%) and severely painful vaso-occlusive event (21.3%). Sixteen (3.3%) patients died in the ICU, mainly of multi-organ failure following a painful vaso-occlusive event or sepsis. An adverse outcome occurred in 81 (16.6%; 95% confidence interval [95% CI], 13.3%-19.9%) patients. Independent factors associated with adverse outcomes were low mean arterial blood pressure (adjusted odds ratio [aOR], 0.98; 95% CI 0.95-0.99; p = 0.027), faster respiratory rate (aOR, 1.09; 95% CI 1.05-1.14; p < 0.0001), higher haemoglobin level (aOR, 1.22; 95% CI 1.01-1.48; p = 0.038), impaired creatinine clearance at ICU admission (aOR, 0.98; 95% CI 0.97-0.98; p < 0.0001), and red blood cell exchange before ICU admission (aOR, 5.16; 95% CI 1.16-22.94; p = 0.031). Patients with SCD have a substantial risk of adverse outcomes if they require ICU admission. Early ICU admission should be encouraged in patients who develop abnormal physiological parameters.

Low hemoglobin increases risk for cerebrovascular disease, kidney disease, pulmonary vasculopathy, and mortality in sickle cell disease: A systematic literature review and meta-analysis

Sickle cell disease (SCD) is characterized by deoxygenation-induced polymerization of hemoglobin in red blood cells, leading to hemolytic anemia, vaso-occlusion, and the development of multiple clinical complications. To characterize the clinical burden associated with differences in hemoglobin concentration and hemolysis measures, a systematic literature review of MEDLINE, EMBASE, and related meta-analyses was undertaken. For quantitative analyses related to hemoglobin concentration, pooled results were analyzed using random effects models to control for within-and between-study variability. To derive risk ratios associated with hemoglobin concentration change, we combined ratios of means from select studies, which reported hazard and odds ratios in meta-analyses for hemoglobin concentration-related outcomes and changes between groups. Forty-one studies were identified for inclusion based on relating hemoglobin concentration to clinical outcomes. Meta-analyses demonstrated that mean hemoglobin concentration was significantly lower in patients with cerebrovascular disease (0.4 g/dL), increased transcranial Doppler velocity in cerebral arteries (0.6 g/dL), albuminuria (0.6 g/dL), elevated estimated pulmonary artery systolic pressure (0.9 g/dL), and in patients that subsequently died (0.6 g/dL). In a risk reduction meta-analysis, modeled increased hemoglobin concentrations of 1 g/dL or greater resulted in decreased risk of negative clinical outcomes of 41% to 64%. In conclusion, chronic anemia is associated with worse clinical outcomes in individuals with SCD and even modest increases in hemoglobin concentration may be beneficial in this patient population. This systematic review has been registered on Prospero (Registration number CRD42018096860; https://www.crd.york.ac.uk/prospero/).

Extracorporeal Life Support for Severe Acute Chest Syndrome in Adult Sickle Cell Disease: A Preliminary Report

OBJECTIVES

Extracorporeal life support could be helpful for severe acute chest syndrome in adults sickle cell disease, because of the frequent hemodynamic compromise in this setting, including acute pulmonary vascular dysfunction and right ventricular failure. The aim of this study was to report the extracorporeal life support experience for severe acute chest syndrome in four referral centers in France.

DESIGN

The primary endpoint of this multicentric retrospective study was ICU survival of patients with severe acute chest syndrome managed with extracorporeal life support. Secondary endpoints included comparisons between survivors and nonsurvivors.

SETTING

We performed this study between January 2009 and July 2017 in four referral centers in France.

PATIENTS

We included adult patients (age > 18 yr) with sickle cell disease, admitted for severe acute chest syndrome and who required extracorporeal life support during the ICU stay.

INTERVENTIONS

The study was observational.

MEASUREMENTS AND MAIN RESULTS

Over the 8-year period, 22 patients with sickle cell disease required extracorporeal life support for severe acute chest syndrome, including 10 (45%) veno-venous and 12 (55%) veno-arterial extracorporeal life support. In-ICU mortality was high (73%). Nonsurvivors had a higher severity at extracorporeal life support implantation, as assessed by their Vasoactive-Inotrope Score and number of organ failures.

CONCLUSIONS

Our study shows that outcome is impaired in sickle cell disease patients receiving extracorporeal life support while in severe multiple organ failure. Further studies are needed to evaluate selection criteria in this setting.

Morpho-functional evaluation of lung aeration as a marker of sickle-cell acute chest syndrome severity in the ICU: a prospective cohort study

Background

Acute chest syndrome (ACS) is the main cause of morbi-mortality in patients with sickle-cell disease in the intensive care unit (ICU). ACS definition encompasses many types of lung damage, making early detection of the most severe forms challenging. We aimed to describe ACS-related lung ultrasound (LU) patterns and determine LU performance to assess ACS outcome.

Results

We performed a prospective cohort study including 56 ICU patients hospitalized for ACS in a tertiary university hospital (Paris, France). LU and bedside spirometry were performed at admission (D0) and after 48 h (D2). Complicated outcome was defined by the need for transfusion of ≥ 3 red blood cell units, mechanical ventilation, ICU length-of-stay > 5 days, or death. A severe loss of lung aeration was observed in all patients, predominantly in inferior lobes, and was associated with decreased vital capacity (22 [15–33]% of predicted). The LU Score was 24 [20–28] on D0 and 20 [15–24] on D2. Twenty-five percent of patients (14/56) had a complicated outcome. Neither oxygen supply, pain score, haemoglobin, LDH and bilirubin values at D0; nor their change at D2, differed regarding patient outcome. Conversely, LU re-aeration score and spirometry change at D2 improved significantly more in patients with a favourable outcome. A negative LU re-aeration score at D2 was an independent marker of severity of ACS in ICU.

Conclusions

ACS is associated with severe loss of lung aeration, whose resolution is associated with favourable outcome. Serial bedside LU may accurately and early identify ACS patients at risk of complicated outcome.

Care of the Critically Ill Pediatric Sickle Cell Patient

Sickle cell disease is the most common inherited disease in the United States. Through the effects of hemolysis and vaso-occlusion, it has the potential to incite critical illness involving multiple organ systems. Children with sickle cell disease are at risk of multiple types of shock resulting in a need for ICU care. Our youngest patients with sickle cell disease are at highest risk of infection due to lack of splenic function, and this can present with septic shock. Hypovolemic shock can occur secondary to severe acute anemia as seen with splenic sequestration or a delayed transfusion reaction. As one ages, the risk of cardiac dysfunction – diastolic and systolic dysfunction as well as pulmonary hypertension – can result in cardiogenic shock. In addition to shock, patients with sickle cell disease are at risk for respiratory failure from acute chest syndrome as well as acute neurologic deterioration from stroke. For these reasons, critical care physicians must be familiar with the unique management of sickle cell complications in order to provide the best possible care for this vulnerable population.

Pulmonary Vascular Dysfunction and Cor Pulmonale During Acute Respiratory Distress Syndrome in Sicklers

BACKGROUND

Acute chest syndrome (ACS) is the most common cause of death among sickle cell disease (SCD) adult patients. Pulmonary vascular dysfunction (PVD) and acute cor pulmonale (ACP) are common during acute respiratory distress syndrome (ARDS) and their prevalence may be even more important during ARDS related to ACS (ACS-ARDS). The objective of this study was to evaluate the prevalence and prognosis of PVD and ACP during ACS-ARDS.

PATIENTS AND METHODS

This was a retrospective analysis over a 10-year period of patients with moderate-to-severe ARDS. PVD and ACP were assessed by echocardiography. ARDS episodes were assigned to ACS-ARDS or nonACS-ARDS group according to whether the clinical insult was ACS or not, respectively. To evaluate independent factors associated with ACP, significant univariable risk factors were examined using logistic regression and propensity score analyses.

RESULTS

A total of 362 patients were analyzed, including 24 ACS-ARDS. PVD and ACP were identified, respectively, in 24 (100%) and 20 (83%) ACS-ARDS patients, as compared with 204 (60%) and 68 (20%) nonACS-ARDS patients (P < 0.0001). The mortality did not differ between ACS-ARDS and nonACS-ARDS patients. Both the crude (odds ratio [OR], 19.9; 95% confidence interval [CI], 6.6-60; P < 0.0001), multivariable adjustment (OR, 27.4; 95% CI, 8.2-91.5; P < 0.001), and propensity-matched (OR, 11.7; 95% CI, 1.2-110.8; P = 0.03) analyses found a significant association between ACS-ARDS and ACP.

CONCLUSIONS

All SCD patients presenting with moderate-to-severe ARDS as a consequence of ACS experienced PVD and more than 80% of them exhibited ACP. These results suggest a predominant role for PVD in the pathogenesis of severe forms of ACS.

Acute kidney injury in children with sickle cell disease-compounding a chronic problem

In an article recently published in Pediatric Nephrology, Baddam and colleagues discuss the relatively underreported clinical problem of repeated episodes of acute kidney injury (AKI) in children with sickle cell disease (SCD). Their report is a cautionary note about the importance of repeated kidney injury on the background of underlying chronic kidney injury and its potential implications on long-term kidney outcome. In children and adults with SCD, this includes the effects of repeated vaso-occlusive crises and the management of these painful episodes with non-steroidal anti-inflammatory drugs. Here we review the scope of kidney involvement in SCD in children and discuss the potential short- and long-term consequences of AKI in children with SCD.

Predictors of mortality in adults with Sickle cell disease admitted to intensive care unit in Bahrain

OBJECTIVE

Sickle cell disease (SCD) is one of the most common genetic blood disorders in Bahrain. However, there is a paucity of data regarding the clinical presentation of SCD patients who require ICU admission. This study aimed to describe the epidemiological data of SCD patients admitted to the ICU and to identify predictors of mortality in order to help intensivists identify patients at most risk.

METHOD

This study used a retrospective, descriptive, and correlational design. Records of 210 SCD patients admitted to the ICU in Salmaniya Medical Complex (SMC) were reviewed.

RESULTS

210 patient with SCD were admitted to ICU during study period. The main reason for ICU admission was acute chest syndrome. The mortality rate of SCD patients in the ICU was 12.7%. The four significant predictors of mortality were age, number of previous hospitalizations, length of stay, and need of renal replacement therapy. Non-survivors were older than survivors (M=38.6 vs. M=30.3years, U=1685, z=-2.2, P=0.025), were less frequently hospitalized (M=19 vs. M=46 times, U=1274, z=-3.7, P=0.000), had shorter lengths of stay in the ICU (M=3.1 vs. M=5.5days, U=1145, z=-4, P=0.000), and more likely to require renal replacement therapy the p=0.0297 than the survivors. The combined effect of these predictors was modelled with cox regression and found to be statistically significant. Gender, presence of comorbid conditions, level of hemoglobin on admission, and need for blood transfusions were not found to be predictors for mortality.

CONCLUSION

Acute chest syndrome was the main reason for SCD patients to be admitted to the ICU. Older age, less frequent hospitalization, shorter stays in the ICU, and the need for renal replacement therapy were found to be indicators of high mortality rate SCD patients.

An uncommon cause of pneumonia: The golden diagnosis

A 28-year-old sub-Saharan African Italian non-smoker male presented with signs and symptoms of pneumonia and respiratory failure. Despite antibiotic treatment he experienced a significant worsening of respiratory conditions and admission to intensive care unit. He thus underwent chest computed tomography followed by fiberopict bronchoscopy with bronchoalveolar lavage whose macroscopic examination led to the diagnosis of acute chest syndrome. A brief literature review was conducted to discuss the first manifestation of this disease.

Rapidly progressive acute chest syndrome in individuals with sickle cell anemia: a distinct acute chest syndrome phenotype

Current definitions of acute chest syndrome (ACS) in sickle cell anemia (SCA) do not account for rapid progression of respiratory compromise. In this two-center retrospective cohort study, we tested the hypothesis that in children and adults with ACS and respiratory failure (≤24 hours after onset of respiratory symptoms) have a distinct ACS phenotype associated with multiorgan failure when compared to those with ACS that have a more subacute and protracted course. We identified 173 individuals (97 children <20 years and 76 adults ≥20 years) with SCA and at least one episode of ACS. Only one ACS episode was considered per individual. Rapidly progressive ACS occurred in 21% (n = 16) of adults, but only 2.1% (n = 2) of children. Compared to adults without rapidly progressive ACS, adults with rapidly progressive ACS more frequently developed acute kidney injury (68.8% vs. 3.3%, P < 0.001), hepatic dysfunction (75.0% vs. 15.0%, P < 0.001), altered mental status (43.8% vs. 11.7%, P < 0.001), multiorgan failure (93.8% vs. 10%, P < 0.001), and death (6.3% vs. 0%, P = 0.05). Clinical and laboratory covariates that were evaluable on the first day of respiratory symptoms were evaluated to identify predictors of rapidly progressive ACS. On multivariable analysis, decline in platelet count at presentation was the only predictor of rapidly progressive ACS [odds ratio 4.82 (95% CI 1.20-19.39), P = 0.027]. In conclusion, rapidly progressive ACS is a distinct phenotype that occurs more frequently in adults, is preceded by thrombocytopenia, and is associated with multiorgan failure. Am. J. Hematol. 91:1185-1190, 2016. © 2016 Wiley Periodicals, Inc.

Prevalence of acute kidney injury during pediatric admissions for acute chest syndrome

BACKGROUND

Patients with sickle cell disease are at risk for developing chronic kidney disease (CKD). Acute kidney injury (AKI) has been linked to progression to CKD, but limited data exist to determine its role in acute complications of sickle cell disease. We hypothesized that AKI occurs in pediatric patients admitted for acute chest syndrome (ACS) and prolongs hospitalization.

METHODS

We conducted a 6-year retrospective review of pediatric patients with ACS admitted to a single medical institution.

RESULTS

Of the 149 pediatric patients admitted for ACS during the 6-year study period, 12 (8 %) developed AKI. Comparison of patients with and without AKI revealed a significant association between AKI and a larger drop in hemoglobin value from baseline (2.7 vs. 1.4 g/dL; p = 0.003), a lower hemoglobin value at admission (6.4 vs. 7.5 g/dL; p = 0.03), and an increased white blood cell count at admission (33.1 vs. 19.8 × 10(9)/L; p < 0.0001), respectively. AKI (p < 0.0001) together with need for advanced respiratory support (biphasic positive airway pressure or mechanical ventilation) (p < 0.0001) and need for exchange transfusion (p < 0.0001) were associated with prolonged hospitalization.

CONCLUSIONS

Clinicians should monitor pediatric patients hospitalized for ACS for the development of AKI as a potentially modifiable risk factor for prolonged hospitalization.

Bedside Lung Ultrasound During Acute Chest Syndrome in Sickle Cell Disease

Lung ultrasound (LU) is increasingly used to assess pleural and lung disease in intensive care unit (ICU) and emergency unit at the bedside. We assessed the performance of bedside chest radiograph (CR) and LU during severe acute chest syndrome (ACS), using computed tomography (CT) as the reference standard. We prospectively explored 44 ACS episodes (in 41 patients) admitted to the medical ICU. Three imaging findings were evaluated (consolidation, ground-glass opacities, and pleural effusion). A score was used to quantify and compare loss of lung aeration with each technique and assess its association with outcome. A total number of 496, 507, and 519 lung regions could be assessed by CT scan, bedside CR, and bedside LU, respectively. Consolidations were the most common pattern and prevailed in lung bases (especially postero-inferior regions). The agreement with CT scan patterns was significantly higher for LU as compared to CR (κ coefficients of 0.45 ± 0.03 vs 0.30 ± 0.03, P < 0.01 for the parenchyma, and 0.73 ± 0.08 vs 0.06 ± 0.09, P < 0.001 for pleural effusion). The Bland and Altman analysis showed a nonfixed bias of -1.0 (P = 0.12) between LU score and CT score whereas CR score underestimated CT score with a fixed bias of -5.8 (P < 0.001). The specificity for the detection of consolidated regions or pleural effusion (using CT scan as the reference standard) was high for LU and CR, whereas the sensitivity was high for LU but low for CR. As compared to others, ACS patients with an LU score above the median value of 11 had a larger volume of transfused and exsanguinated blood, greater oxygen requirements, more need for mechanical ventilation, and a longer ICU length of stay. LU outperformed CR for the diagnosis of consolidations and pleural effusion during ACS. Higher values of LU score identified patients at risk of worse outcome.

Sickle cell disease: renal manifestations and mechanisms

Sickle cell disease (SCD) substantially alters renal structure and function, and causes various renal syndromes and diseases. Such diverse renal outcomes reflect the uniquely complex vascular pathobiology of SCD and the propensity of red blood cells to sickle in the renal medulla because of its hypoxic, acidotic, and hyperosmolar conditions. Renal complications and involvement in sickle cell nephropathy (SCN) include altered haemodynamics, hypertrophy, assorted glomerulopathies, chronic kidney disease, acute kidney injury, impaired urinary concentrating ability, distal nephron dysfunction, haematuria, and increased risks of urinary tract infections and renal medullary carcinoma. SCN largely reflects an underlying vasculopathy characterized by cortical hyperperfusion, medullary hypoperfusion, and an increased, stress-induced vasoconstrictive response. Renal involvement is usually more severe in homozygous disease (sickle cell anaemia, HbSS) than in compound heterozygous types of SCD (for example HbSC and HbSβ(+)-thalassaemia), and is typically mild, albeit prevalent, in the heterozygous state (sickle cell trait, HbAS). Renal involvement contributes substantially to the diminished life expectancy of patients with SCD, accounting for 16-18% of mortality. As improved clinical care promotes survival into adulthood, SCN imposes a growing burden on both individual health and health system costs. This Review addresses the renal manifestations of SCD and focuses on their underlying mechanisms.