Simultaneous occurrence of atypical hemolytic uremic syndrome and acute lymphoblastic leukemia: a case report and literature review

Rare Presentation of Atypical Hemolytic Uremic Syndrome in a Child With Acute Lymphocytic Leukemia and Pancreatitis

Atypical hemolytic uremic syndrome (aHUS) is associated with significant mortality and morbidity, including acute renal injury, anemia and thrombocytopenia. Rare cases of aHUS in a child with acute leukemia before diagnosis or during chemotherapy have been reported. We report a pediatric case of B-cell acute lymphoblastic leukemia complicated by pancreatitis with concomitant aHUS following induction chemotherapy.

A Limited Course of Eculizumab in a Child with the Atypical Hemolytic Uremic Syndrome and Pre-B Acute Lymphoblastic Leukemia on Maintenance Therapy: Case Report and Literature Review

Acute lymphoblastic leukemia (ALL) is considered a possible risk for the occurrence of thrombotic microangiopathies. We present a girl with pre-B ALL successfully treated according to the BFM ALL IC-2009 protocol on maintenance therapy followed by aHUS occurrence. This is the seventh case of HUS/aHUS on ALL maintenance therapy and the first with clearly documented eculizumab use in the early stage of aHUS/secondary TMA. Standard and additional parameters were used in aHUS monitoring alongside the reticulocyte production index adjusted for age (RPI/A) and the aspartate aminotransferase-to-platelet ratio index (APRI) as markers of hemolysis and rapid response following treatment. RPI/A and APRI are markers of bone marrow response to anemia serving as red blood cell vs. platelet recovery markers. Together they mark the exact recovery point of thrombotic microangiopathy and serve as a prognostic marker of eculizumab treatment success. During the 8-month treatment and 6-month follow-up, no recurrence of hemolysis, ALL relapse, or renal damage were observed. A systematic review of the literature revealed 14/312 articles; five children had aHUS before the onset of ALL, and two children had both diseases concurrently. At least 3/7 patients are attributed to aHUS, of whom 2/7 have renal damage. Potential undiagnosed/unpublished cases may be assumed.

Successful Management of a Rare Cause of Hemolytic Uremic Syndrome With Eculizumab in a Child

BACKGROUND

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, acute renal failure, and thrombocytopenia. It very rarely coexists with acute lymphoblastic leukemia (ALL) emerging before, simultaneously, or after the diagnosis has been made, and management of the patient may be difficult.

CASE

We present the case of a 7-year-old boy who was diagnosed with HUS and initially managed by hemodialysis (HD). Thereafter, HUS progressed, and neurological findings developed. The patient was treated with eculizumab, agressive blood pressure control, and antiepileptic drugs. At the fifth month of follow-up, the patient was diagnosed with acute B-cell lymphoblastic leukemia with fever, bone pain, hepatosplenomegaly, and pancytopenia. After initiation of ALL treatment, he had no episodes of HUS, despite cessation of eculizumab.

CONCLUSION

In conclusion, eculizumab may be a treatment of choice to prevent further systemic damage in recurrent HUS episodes of patients with borderline changes in the bone marrow until ALL is constantly diagnosed.

Podocyte dysfunction in atypical haemolytic uraemic syndrome

Genetic or autoimmune defects that lead to dysregulation of the alternative pathway of complement have been associated with the development of atypical haemolytic uraemic syndrome (aHUS), which is characterized by thrombocytopenia, haemolytic anaemia and acute kidney injury. The relationship between aHUS, podocyte dysfunction and the resultant proteinuria has not been adequately investigated. However, the report of mutations in diacylglycerol kinase ε (DGKE) as a cause of recessive infantile aHUS characterized by proteinuria, highlighted podocyte dysfunction as a potential complication of aHUS. DGKE deficiency was originally thought to trigger aHUS through pathogenetic mechanisms distinct from complement dysregulation; however, emerging findings suggest an interplay between DGKE and complement systems. Podocyte dysfunction with nephrotic-range proteinuria can also occur in forms of aHUS associated with genetic or autoimmune complement dysregulation without evidence of DGKE mutations. Furthermore, proteinuric glomerulonephritides can be complicated by aHUS, possibly as a consequence of podocyte dysfunction inducing endothelial injury and prothrombotic abnormalities.

Haemolytic uraemic syndrome preceding acute lymphoblastic leukaemia

An 11-year-old girl presented with diarrhoea associated haemolytic uraemic syndrome (HUS) requiring haemodialysis. Four weeks following the resolution of her renal impairment, she was found to have cervical lymphadenopathy alongside deterioration in her renal function. While blood films during her acute illness were indicative of sepsis only, subsequent film revealed a diagnosis of acute lymphoblastic leukaemia (ALL). Thus, this report describes a rare case of diarrhoea associated HUS preceding the diagnosis of ALL, and may represent an unusual presentation of the malignancy.

Nephrotic syndrome developing during induction chemotherapy for childhood acute lymphoblastic leukemia

This report is the first to document minimal change nephrotic syndrome occurring during induction chemotherapy for childhood acute lymphoblastic leukemia (ALL). This occurrence lends further support to the theory of immune cell dysregulation being central to the pathogenesis of nephrotic syndrome in ALL, rather than alternative postulations that this association is due to an increased risk of malignancy secondary to prior immunosuppressive treatment for nephrotic syndrome.

Haemolytic uraemic syndrome in a patient with acute lymphoblastic leukaemia

We describe a patient diagnosed with haemolytic uraemic syndrome (HUS) during long-term maintenance therapy for childhood acute lymphoblastic leukaemia (ALL). He rapidly developed renal failure, hypertension and profound thrombocytopenia. Despite suffering a large intracerebral haemorrhage, he made a full recovery without residual neurological or renal deficit. His case raises the question of whether ALL or its treatments predispose an individual to developing HUS.