Idiopathic Systemic Capillary Leak Syndrome: A Rare Cause of Refractory Shock Following Influenza B Infection

A 68-year-old man presented to the Emergency Department with undifferentiated shock. During the three days prior, he experienced a non-specific viral-like illness. On examination his blood pressure was 70/40 mm Hg with cool, clammy, and mottled extremities and flat neck veins. Laboratory investigations revealed a positive influenza B screen alongside elevated hemoglobin and hematocrit. Following aggressive fluid resuscitation his blood pressure had marginally improved and he was transferred to the intensive care unit (ICU). Vasopressor support with cautious fluid resuscitation continued and at 7- and 10-h following presentation, serum albumin levels were extremely low. Idiopathic systemic capillary leak syndrome triggered by influenza B infection was diagnosed. Following a 9-day ICU stay the patient made a complete recovery and remains stable on intravenous immunoglobulin therapy. This case highlights the importance judicious fluid resuscitation and serum albumin levels when confronted with refractory shock.