A case of Moyamoya disease complicated by aHUS in a patient with a history of marginal zone B-cell lymphoma: lightning strikes thrice?

Atypical haemolytic uraemic syndrome (aHUS) is a rare, acquired thrombotic microangiopathy, mediated by complement activation, in very sick patients. Moyamoya is similarly a rare disease in which stenosis or occlusion of segment(s) of the anterior cerebral circulation leads to the formation of many thin collaterals. Other reports have described an association between HUS and Moyamoya disease in the paediatric population. However, this case study presents the exceptionally rare presentation of an adult with aHUS and Moyamoya disease in a patient who was treated with rituximab for marginal zone B-cell lymphoma.

Atypical Presentation of Pregnancy-Related Hemolytic Uremic Syndrome.

The cause of acute kidney injury during pregnancy and in the postpartum period can be particularly challenging to diagnose, especially when it is necessary to differentiate among preeclampsia; eclampsia; hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome; and thrombotic microangiopathies (TMAs). All these disease entities can present with kidney failure, microangiopathic hemolytic anemia, and thrombocytopenia. We present a teaching case of atypical hemolytic uremic syndrome in the postpartum period in a young woman who was found to have mutations of uncertain clinical significance in the complement cascade, including in C3, CFH, and CFI. We use this as an opportunity to review the clinical presentation and pathophysiology of preeclampsia, eclampsia, and the TMAs. We focus on diagnostic challenges, especially because many patients with TMA do not present with thrombocytopenia, which can delay diagnosis. We additionally review the clinical settings in which administration of eculizumab, a C5 membrane attack complex inhibitor, is appropriate.

Leptospirosis presenting as haemolytic uraemic syndrome: a case report.

BACKGROUND: Leptospirosis is a rare infectious disease especially in Western Countries. Renal involvement is a recognised complication of leptospirosis but leptospirosis-associated haemolytic uraemic syndrome is extremely rare and to our knowledge has only been reported once, in 1985. CASE PRESENTATION: A 29-year-old male was transferred to our Renal Unit with fevers, myalgia and diarrhoeal illness. Laboratory investigations revealed an acute kidney injury, acute liver injury, significantly raised lactate dehydrogenase with marked anaemia, thrombocytopenia and schistocytes on a blood film. A diagnosis of haemolytic uraemic syndrome was made. Surprisingly, the stool culture was negative which led to a suspicion of leptospirosis as one of the differential diagnoses. This was subsequently confirmed by enzyme-linked immunosorbent assay and microscopic agglutination test. He received plasma exchange and antibiotics and made a complete recovery on discharge. CONCLUSION: Leptospirosis presenting as haemolytic uraemic syndrome is rare but should be considered in the differential diagnosis especially in the presence of significant liver injury, as current evidence suggests that the disease is re-emerging.

Complement activation: an atypical presentation of an atypical syndrome.

A 42-year-old Hispanic female and long-distance runner was seen for evaluation of fatigue. Her physical examination showed petechiae and ecchymoses in upper extremities, abdominal distension and bilateral ankle oedema. Laboratory workup revealed anaemia, thrombocytopenia, hypoalbuminemia and proteinuria of 1.4 g/24 hours. No schistocytes were found on peripheral blood smear. CT of her abdomen revealed diffuse small lymphadenopathy and hepatomegaly. Bone marrow biopsy demonstrated normal trilineage hematopoiesis with no hemophagocytosis. The patient was started on oral prednisone with no improvement and was subsequently admitted to the hospital for pulsed steroids, intravenous immunoglobulin and rituximab. Her proteinuria became nephrotic range, and a renal biopsy revealed features of thrombotic microangiopathy limited to the glomerular capillaries. ADAMTS13 was low which is >10% of normal, and a diagnosis of atypical haemolytic-uraemic syndrome (aHUS) was made. Eculizumab was started with prompt response. Whole exome sequencing demonstrated mutation in SPTA1, which has been associated with red blood cell membrane diseases but has not been described in patients with aHUS.