D ARIYARATHNA1, D HSU2, J YONG3, M KILLINGSWORTH3, J RUTLAND4, J WONG1
1Renal unit Liverpool Hospital, Liverpool, New South Wales; 2Haematology Department Liverpool Hospital, Liverpool, New South Wales; 3Anatomical Pathology Liverpool Hospital, Liverpool, New South Wales; 4Respiratory Department Liverpool Hospital, Liverpool, New South Wales.
Background: Acute kidney injury (AKI) due to Legionnaires’ disease is attributed to acute interstitial nephritis or acute tubular necrosis. There exists a single case report of Legionella pneumophila associated with haemolytic uraemic syndrome (aHUS). To our knowledge, this report is the first of Legionnaires’ disease due to Legionella longbeachae associated AKI due to aHUS.
Case Report: A 74-year-old avid male gardener with pneumonia presented with initial investigations revealing normal renal function and platelet count, but on day 7he developed oliguric AKI with creatinine 395 µmol/L requiring dialysis. Urine was negative for white cells, red cells or casts. He was proteinuric with 0.99g/day. Vasculitic screen were negative. Renal ultrasound revealed normal sized kidneys and collecting systems. Subsequently his platelets reduced to 85 x109/L and haemoglobin to 58g/L. Peripheral blood film revealed schistocytes and red cell fragments. Haptoglobin was <0.08g/L and lactate dehydrogenase 1312, consistent with thrombotic microangiopathy (TMA). Shiga toxin was negative, ADAMTS 13 was 54%. Plasma exchange improved his platelet count to 163×109/L. Eculizumab was commenced on day 11 with no further evidence of microangiopathic haemolysis. Renal biopsy showed protein fibrin thrombi in glomerular capillary lumens consistent with TMA and concomitant interstitial nephritis and ATN. On 3 months follow up, his creatinine, LDH, haptoglobin and platelets had normalised. He had reduced membrane cofactor protein (MCP) 0.76. Complement factors I was 36mg/L (NR, 38-58mg/L) and CFH >700mg/L (NR, 350-590mg/L). Serology confirmed Legionella longbeachae serotype 1, which we believe is the precipitant of his aHUS.
Conclusions: We present the first aHUS case attributed to legionella longbeachae, with this gentleman expressing reduced MCP. With early suspicion of aHUS, he responded extremely well to Eculizumab treatment.