Multiorgan failure and bone marrow necrosis in three adults with sickle cell-β+ -thalassemia

Stroke in sickle cell disease and the promise of recent disease modifying agents

Sickle cell disease (SCD) is an inherited hemoglobinopathy affecting approximately 100,000 individuals in the United States. Cerebrovascular disease is among the most common and debilitating complications of SCA, with 53% experiencing silent cerebral infarct by age 30 and 3.8% experiencing overt stroke by age 40 years. This review highlights the burden of cerebrovascular disease in SCD, including both stroke and silent cerebral infarct (SCI). We then discuss the pathophysiology of stroke and cerebral fat embolism in the absence of a patent foramen ovale. This review also reveals that options for primary and secondary stroke prevention in SCD are still limited to hydroxyurea and blood transfusion, and that the role of aspirin and anticoagulation in SCD stroke has not been adequately studied. Limited data suggest that the novel disease-modifying agents for SCD management may improve renal dysfunction, leg ulcers, and lower the abnormally high TCD flow velocity. Further research is urgently needed to investigate their role in stroke prevention in SCD, as these novel agents target the main stroke contributors in SCD - hemolysis and vaso-occlusion. This literature review also explores the role of healthcare disparities in slowing progress in SCD management and research in the United States, highlighting the need for more investment in patient and clinician education, SCD management, and research.

Pitfalls in Diagnosing Thrombotic Thrombocytopenic Purpura in Sickle Cell Disease

Thrombotic thrombocytopenia purpura is characterised by microangiopathic haemolytic anaemia and red cell fragmentation on the peripheral smear, neurological involvement and thrombocytopenia. Diagnosis in the context of sickle cell disease can be challenging due to the inherent haemolytic state and the multitude of other associated complications of the latter. Specifically, fat embolism syndrome characterised by respiratory failure, neurological impairment and thrombocytopenia can be misdiagnosed this way. Confirmation of a diagnosis of thrombotic thrombocytopenic purpura requires demonstration of very low levels (<10%) of the metalloproteinase ADAMTS13 which in fat embolism syndrome is normal. Existing scoring systems used to estimate the pre-test probability for thrombotic thrombocytopenic purpura cannot be applied in patients with sickle cell disease due to the chronic underlying haemolysis. Here, we analyse the diagnostic approach in published cases of thrombotic thrombocytopenic purpura affecting patients with sickle-cell disease. The vast majority of cases were characterised by severe respiratory failure before any other manifestation, a feature of fat embolism syndrome but not of thrombotic thrombocytopenic purpura, and all received red cell transfusion prior to receiving therapeutic plasma exchange. Despite the potential overestimation of the pre-test probability using the existing scoring systems, a large number of cases still scored low. There were no cases with documented low ADAMTS13. In the majority this was not tested, while in the 3 cases that ADAMTS13 was tested, levels were normal. Our review suggests that due to many overlapping clinical and laboratory features thrombotic thrombocytopenic purpura may be erroneously diagnosed in sickle cell disease instead of other complications such as fat embolism syndrome and confirmation with ADAMTS13 testing is essential.

Fat Embolism Syndrome in Sickle Cell β-Thalassemia Patient With Osteonecrosis: An Uncommon Presentation in a Young Adult

Fat embolism syndrome is a relatively infrequent presentation in sickle cell thalassemia patients. It most commonly occurs in long bone fractures in the setting of trauma. However, nonorthopedic trauma and nontraumatic cases have been reported to contribute to fat embolism. The fat embolic syndrome is an underdiagnosed, life-threatening, and debilitating complication of sickle-β-thalassemia–related hemoglobinopathies. It is primarily seen in milder versions of sickle cell disease, including HbSC and sickle cell β-thalassemia, with the mild prior clinical course without complications; hence, diagnosis can be easily missed. Pathogenesis of fat embolic syndrome is a combination of mechanical obstruction from fat globules released into systemic circulation at the time of bone marrow necrosis and direct tissue toxicity from fatty acids and inflammatory cytokines released from fat globules. Prompt diagnosis and early initiation of treatment can reduce morbidity and mortality and result in better outcomes and prognosis. Red cell exchange transfusion is the mainstay of therapy with mortality benefits. Overall mortality and neurological sequelae continue to be high despite increased red cell exchange transfusion in the last few years. In this article, we discussed a case of a 34-year-old male patient with a history of sickle cell thalassemia and avascular necrosis of the hip, who presented with fever, hypoxia, encephalopathy, and generalized body aches, found to have thrombocytopenia and punctate lesions on magnetic resonance imaging brain, which led to the diagnosis of the fat embolism syndrome. Only a few sickle cell β-thalassemia with fat embolic syndrome cases have been reported.

Bone marrow necrosis and fat embolism syndrome: a near fatal complication in previously undiagnosed sickle beta + thalassaemia

Prevalence of haemoglobin sickle-β⁺ thalassaemia (Hb S/β+thal) is variable with geography ranging from 0.2% to 10% among sickle cell patients. Clinical presentation of Hb S/β+thal patients depends on HbA level, with milder disease often going undiagnosed. However, rarely these patients can present with a fulminant vaso-occlusive crisis (VOC). Given VOC can present with non-specific symptoms, the diagnosis and treatment is often delayed. Here, we present a patient who initially developed altered mental status, pancytopenia and multiorgan failure due a critical VOC resulting in bone marrow necrosis and fat embolism. Subsequent workup confirmed that our patient had Sickle-β⁺ thalassaemia, which had gone undiagnosed, despite subclinical evidence of haemolysis on routine lab work for years. Following diagnosis and initiation of RBC exchange, he improved significantly and was discharged home. High index of suspicion and bone marrow biopsy is vital for early diagnosis and management of this rare condition.

Extensive Bone Marrow Necrosis: Initial Presentation in Sickle Cell Anemia-A Case Report and Review of the Literature

Bone marrow necrosis (BMN) is a rare clinical entity that was first described in an autopsy of a sickle cell disease (SCD) patient and is defined as ill-defined necrotic cells in an amorphous eosinophilic background with preservation of cortical bone. The pathophysiology of BMN is not well known; however, occlusion of the bone marrow microcirculation with subsequent hypoxia and cell injury has been thought to be common underlying features. Malignancy has been identified to be the primary cause in 90% of the cases whereas SCD was found in only 2%. In this report we present an unusual case of SCD with late onset of the disease whose initial presentation was extensive BMN. The patient was not known previously to have SCD, when suddenly she presented with severe cytopenias and marked elevation in serum lactate dehydrogenase (LDH). Bone marrow examination was done to exclude bone marrow infiltration, and BMN with dilated marrow sinuses full of irreversibly sickled cells were the unexpected findings. Patients with a mild SCD phenotype are at high risk of BMN. Thus, a high index of suspicion must be borne in mind, particularly in an area of high SCD prevalence, to recognize and prevent this catastrophic complication.

Successful outcome of three patients with sickle-cell disease and fat embolism syndrome treated with intensive exchange transfusion

Fat embolism syndrome (FES) is a rare complication of sickle-cell disease (SCD) associated with extremely high mortality rates. It affects predominantly non-SS patients and those with previously mild disease. Rapid institution of exchange transfusion with an aim to reduce HbS to very low levels as soon as FES is suspected can be life-saving.

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.

Study of Twenty One Cases of Red Cell Exchange in a Tertiary Care Hospital in Southern India

INTRODUCTION

Red Cell Exchange (RCE) is removal of a patient's red blood cells while replacing with donor red blood cells either manually or using automated systems. RCE is beneficial in patients with Sickle Cell Disease (SCD) either during sickling crisis or prior to major surgical procedures to bring down the sickling percentage as high sickling percentage during prolonged anaesthesia may lead to vaso-occlusive crisis. It is also employed in patients infested with malaria and babesiosis where parasitic index remain high despite medical management. RCE is also tried as an adjuvant therapy in certain poisons like nitrobenzene and carbon monoxide when first line management fails.

AIM

To study the effectiveness, clinical outcome, challenges and complications of RCE in various clinical scenario and to understand how this procedure can be effectively utilized in the management of patients in Indian scenario.

MATERIALS AND METHODS

This retro prospective study was conducted in tertiary care center in southern India which analyzed 21 RCE procedures performed on patients with different clinical conditions. Of the 21 RCE performed, 18 procedures were performed on patients with case of sickle cell disease, Two procedures were performed on patients infested with severe falciparum malaria and one procedure was performed on a patient with nitrobenzene poisoning. All procedures were performed using Spectra Optia(®) Apheresis System - Terumo BCT.

RESULTS

All the 18 patients who underwent the RCE for sickle cell anaemia were admitted for hemi-arthroplasty for avascular necrosis of the head of femur. The average initial HbS levels were between 73-85% and post RCE it was brought down to 22-29% and was achieved in a single sitting in all the cases. Among the two patients infested with severe falciparum malaria, RCE helped in reducing the infestation rate. In case of nitrobenzene poisoning, RCE helped in improvement of oxygen saturation and patient showed significant improvement.

CONCLUSION

RCE is an safe and clinically effective therapeutic modality with very minimal to nil side effects. RCE is possibly underutilized therapy in developing world like India due to various reasons like inadequate awareness/ technical expertise, lack of equipments and facilities to identify the clinical conditions per se etc.