Diagnostic dilemma in a patient presenting with thrombotic microangiopathy in the setting of pregnancy

We report a case of thrombotic microangiopathy in a postpartum female for which considerable diagnostic uncertainty existed initially regarding the etiology. This case highlights the limitations surrounding PLASMIC scoring criteria for the diagnosis of thrombotic thrombocytopenic purpura (TTP). A 32-year-old woman presented to maternofetal medicine in her third trimester of pregnancy at 32 weeks for a routine follow up and was subsequently found to have elevated blood pressures with proteinuria, and was diagnosed with pre-eclampsia. Worsening anemia and thrombocytopenia prompted a blood smear which showed schistocytes, concerning for a thrombotic microangiopathy. Creatinine was also elevated with normal liver enzymes being noted. A PLASMIC score of 4 placed her in the low-risk category for severe ADAMTS13 deficiency whilst she fulfilled criteria for partial HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome per Tennessee classification. Despite delivery, her symptoms persisted with subsequent ADAMTS13 assay confirming acquired TTP, subsequently requiring repeated plasmapheresis and rituximab to achieve disease control. Thrombotic microangiopathy remains a diagnostic challenge especially in the peripartum population, and scoring systems such as PLASMIC score and Tennessee classification may be of limited utility.