Atypical HUS: A Rare Life-Threatening Pregnancy Complication Not to Miss

Abstract

Case Description: 32yo G2P2002 woman developed hypertension and AKI on the day after her c-section. She also had vision and mental status changes, headaches, paresthesia, dyspnea, and abdominal pain. Her labs were significant for increased LFTs, thrombocytopenia, and worsening kidney function. After receiving urgent hemodialysis and not responding to plasmapheresis, she was diagnosed with atypical hemolytic-uremic syndrome (aHUS) and started on eculizumab which resulted in significant improvement. She continued to receive dialysis for 2.5 weeks. Conclusions: Atypical hemolytic uremic syndrome is a rare but life-threatening postpartum complication that can resemble other conditions like preeclampsia, HELLP, and TTP. Post-partum patients experiencing hypertension or other kidney injury symptoms should be evaluated further and started on eculizumab early to prevent permanent kidney damage. Clinical Significance: Pregnancy represents a complement amplifying condition which may reveal underlying genetic abnormalities. When working up women who experience acute kidney injury (AKI) during pregnancy, it is important to consider risk preceding obstetric conditions such as hypertensive disorders (preeclampsia, HELLP), fetal death, and hemorrhagic events which may trigger disorders like aHUS/TTP. Plasma exchange response can help differentiate TTP from aHUS. If unresponsive to plasmapheresis, eculizumab effectively treats aHUS by inhibiting the terminal complement cascade. Renal recovery after aHUS is variable. Women can undergo complete recovery or long term dialysis with eventual kidney transplantation. Early initiation of Eculizumab is linked to greater improvement in GFR after one month and fewer incidences of end-stage renal disease. Recurrent episodes of aHUS are possible and prophylactic Eculizumab has been shown to decrease the likelihood of recurrence. Future pregnancies are advised against due to the risk of pregnancy to cause further thrombotic events.