Systemic capillary leak syndrome (SCLS) is characterized by intermitte
nt attacks of leakage of intravascular fluids into the extravascular s
pace. Hypovolemia, hemoconcentration, weakness, edema, and visceral co
ngestion are resulting manifestations of SCLS. Most patients with SCLS
have clear mentation during attacks, and encephalopathy is not a know
n manifestation of the syndrome. We report a patient with acute idiopa
thic capillary leak syndrome manifested in an acute encephalopathy. Th
e possibility of SCLS should be considered in patients who have an enc
ephalopathy and hemoconcentration.