Idiopathic systemic capillary leak syndrome: a case report.

BACKGROUND: Idiopathic systemic capillary leak syndrome (ISCLS) is a rare disease characterized by recurrent episodes of acute life-threatening attacks of shock, hemoconcentration, and hypoalbuminemia. Increase in capillary permeability results in reversible plasma movement into the interstitial spaces followed by appearance of related symptoms or complications, including renal failure. This condition can be potentially life-threatening; however, it is easily misdiagnosed. CASE PRESENTATION: A 47-year-old man with no previous medical history presented to the emergency department after experiencing general weakness and abdominal pain. He developed hypovolemic shock within 3 h of presentation and initial laboratory tests showed hemoconcentration, hypoalbuminemia and acute kidney injury. Following vigorous fluid therapy and supportive care, the patient recovered, but a similar episode recurred after 4 months without any specific trigger. Based on the combined clinical manifestations and laboratory findings of both the attacks, he was diagnosed with ISCLS. Symptomatic relief was achieved via oxygen supplementation and massive volume replacement using normal saline and the patient was prescribed bambuterol 10 mg and theophylline 400 mg once-a-day. He was discharged from the hospital on day 5 of hospitalization. Thereafter, the patient has been followed for 5 years without any symptoms or recurrence of ISCLS even in the situation of COVID-19 infection. CONCLUSIONS: ISCLS is an extremely infrequent and commonly misdiagnosed disease. However, early diagnosis, treatment and prophylaxis through accumulated clinical data can prevent ISCLS recurrence and the development of related fatal complications. Therefore, clinicians need to be well aware of the variety of clinical characteristics and treatment options of this disease.

Idiopathic systemic capillary leak syndrome, a unique complement and interferon mediated endotheliopathy syndrome: The role of the normal skin biopsy in establishing the diagnosis and elucidating pathogenetic mechanisms.

Idiopathic Systemic Capillary Leak Syndrome (ISCLS), also known as Clarkson's Syndrome, is due to primary fluid and protein leak across capillaries that leads to an accumulation of interstitial fluids and cardiovascular collapse from intravascular hypovolemia. Viral infections are a putative trigger of these episodes. ISCLS is typically associated with a monoclonal gammopathy. Here we present four patients with idiopathic systemic capillary leak syndrome. The cohort consists of three men and one woman who range in age from 55 to 72 years old. All of the patients had a monoclonal gammopathy. Two patients had viral triggers. Biopsies of normal skin were examined throughout all phases of the disease. During an acute attack, we identified perivascular mixed CD4+ and CD8+ T cell lymphocytic infiltrates in the superficial dermis. We observed significant microvascular deposits of C5b-9 and upregulation of type I interferon signaling in endothelium along with reduced serum levels of complement during very active disease. We also identified deposits of immunoglobulin along the dermal epidermal junction mirroring the monoclonal immunoglobulin isotype implicated in each patient. During a post treatment recovery or mild disease phase there was reduced inflammation and decreased amounts of C5b-9 and type I interferon expression. Sudden onset capillary leak syndrome reflects enhanced endothelial cell permeability as a unique form of endothelial injury mediated by the combined effects of complement pathway activation and upregulation of type I interferon signaling on endothelium.