Case Presentation: A 36-year-old male with no past medical history presented to the emergency room for medical evaluation for one week of diarrhea that became bloody four days prior to presentation. During the hospitalization, he had worsening thrombocytopenia and labs were consistent with Shiga Toxin 2 positive hemolytic uremic syndrome. He was managed with supportive care but while his platelet count and kidney function improved, the patient developed dizziness, blurred vision, and seizures. Magnetic resonance imaging revealed bilateral thalamic and inferior colliculi infarcts. Lumbar puncture was unrevealing. The patient was treated with plasma exchange but had no meaningful improvement and his seizures persisted. After three days of plasma exchange therapy, Eculizumab was administered and the patient had a drastic response within hours of receiving the medication, with cessation of seizures and successful extubation on the same day. Over the following week, the patient had significant recovery of neurological function. The patient received a second dose of the Eculizumab and was discharged home without any additional dose. On 2-month follow-up, the patient was active in his prior occupation and had returned to baseline.
Discussion: Hemolytic Uremic Syndrome (HUS) is a thrombotic microangiopathy (TMA) classically described by the presence of a triad of signs: thrombocytopenia, acute renal impairment, and microangiopathic hemolytic anemia. The majority of cases occur in children less than 5 years old and over 90% of typical HUS is caused by Shiga-toxin producing Escherichia coli. In contrast, atypical HUS is most often caused by genetic mutations that cause chronic complement overactivation causing systemic TMA syndrome, and up to 40% of atypical HUS is associated with Streptococcus pneumoniae infections. Typical HUS is self-limited, and the treatment is usually supportive care. Atypical HUS is treated with plasma exchange and potentially with terminal complement inhibitors such as Eculizumab.Our patient presented with typical HUS with positive Shiga-toxin, and the standard of care would have been supportive care. However, with worsening neurological function and clinical status, the patient was given a trial of plasma exchange and Eculizumab with the unexpected result that he was exquisitely responsive to Eculizumab.
Conclusions: In this patient with clinical history and laboratory testing consistent with typical HUS, Eculizumab appeared to be an effective therapy that reversed the syndrome and resulted in complete neurological recovery. There may be a subset of patients in typical HUS with complement system involvement who may benefit from such therapy to be investigated further.