Idiopathic systemic capillary leak syndrome (Clarkson syndrome) in childhood: systematic literature review

Approximately 500 cases of idiopathic systemic capillary leak syndrome (Clarkson syndrome) have been reported worldwide. This life-threatening condition is characterized by episodes of increase in vascular permeability with loss of fluid into the interstitium and presents with acute onset of edema, signs of tissue hypoperfusion, hemoconcentration, and low blood protein level. It has been diagnosed mainly in middle-aged adults with a monoclonal gammopathy. We performed a systematic review of the literature on Clarkson syndrome in subjects ≤ 18 years of age. We identified 24 reports, published since 1989, providing data on 32 otherwise healthy subjects, who experienced 67 well-documented episodes of Clarkson syndrome. The condition affected more frequently girls (21, 66%) than boys, presented throughout childhood, and was preceded by a mostly viral illness in 75% of cases. A monoclonal gammopathy was never reported. Uncompensated circulatory shock, muscle compartment syndrome, acute kidney injury, pulmonary edema, and either pleural or pericardial effusion were, in decreasing order of frequency, the most common complications. Four patients died.