T GOREGUES1,2, S GOVINDARAJULU1
1Toowoomba Hospital Nephrology Service, Toowoomba, Australia, 2Griffith University, Southport, Australia
Background: Differentiating between atypical haemolytic uraemic syndrome (aHUS) and other thrombotic microangiopathies (TMA) can be clinically challenging. In all forms of TMA, the abdominal symptoms due to mesenteric ischaemia can resemble peritonitis or appendicitis. A high index of suspicion is needed for prompt diagnosis because early initiation of treatment reduces the risk of end organ damage.
Case Report: We report a case of a previously healthy 25-year-old female (G11P3M8) presenting with abdominal pain and nausea with CT-confirmed acute appendicitis. Despite early broad-spectrum intravenous antibiotics, she deteriorated 48 hours into her admission developing new onset hypertension (blood pressure 160/100 mmHg), worsening abdominal pain and jaundice. Laboratory examination was consistent with TMA demonstrating severe thrombocytopaenia (platelets 5 x10⁹/L), microangiopathic haemolytic anaemia (haemoglobin 77 g/L with schistocytes on blood smear, lactate dehydrogenase 3260U/L, bilirubin 240μmol/L), acute kidney injury (creatinine peaking to 276μmol/L) and an active urinary sediment (urine albumin-creatinine ratio 804g/mol, erythrocytes 500×10⁶/L). There was no prodrome of diarrhoea and stool was negative for Shiga-toxin. Coagulation studies and ADAMTS13 activity were normal. A clinical diagnosis of aHUS was made. Surgery and renal biopsy were contraindicated due to thrombocytopenia. She was commenced on eculizumab treatment and had a favourable response mitigating the need for renal replacement therapy (RRT).
Conclusions: To our knowledge, this is the first reported case of appendicitis triggering aHUS in an adult and only several case reports exist in children. Eculizumab has proven efficacy in the treatment of aHUS though treatment duration and when to cease treatment remain controversial topics. Evidence from case reports and case series have shown promise in the short-term use of eculizumab to treat secondary causes of aHUS.
Thomas Goregues is a first year Nephrology Advanced Trainee in Toowoomba Hospital in regional Queensland.