Schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH): A comprehensive review of diagnosis and management

Highlights

• SCH-PH should be suspected in patients who live or travel to endemic areas and present with progressive dyspnea.

• The initial work typically includes echocardiogram and if suggestive of pulmonary hypertension or right ventricular dysfunction, right heart catheterization must be performed.

• Clinical clues such as the presence of eosinophilic or enlargement of left lobe of liver in a patient with pulmonary arterial hypertension should lead to a suspicion of chronic schistosomiasis.

• Diagnosis of Schistosomiasis associated pulmonary hypertension requires the confirmation of all the three features that include the presence of pre-capillary pulmonary hypertension, diagnosis of chronic schistosomiasis needs to be established and evidence of hepato-splenic form of the disease.

• Management of SCH-PAH includes the treatment of schistosomiasis with Praziquantel and the management of pulmonary arterial hypertension according to the validated risk assessment tools such as three strata and four strata model using a combination of PDE-5 inhibitors and endothelin receptor antagonist.

Abstract

Schistosomiasis is the second most dangerous parasitic disease, affecting approximately 200 million people worldwide. Chronic Schistosomiasis, especially the hepatosplenic form, can lead to the development of pulmonary arterial hypertension and has been classified as a distinct entity referred to as “Schistosomiasis-associated pulmonary arterial hypertension” (Sch-PAH). Several mechanisms may play a role in the pathogenesis of Sch-PAH, which include peri-ovular granulomatous inflammation with subsequent vascular remodeling. Pro-inflammatory and pro-fibrotic cytokines with altered downstream signaling of bone morphogenic protein receptor 2 pathway (BMRP-2) have been hypothesized based on the mouse models. Diagnosis of Sch-PAH requires confirmation of pre-capillary pulmonary arterial hypertension by right heart catheter and further evaluation of etiology in those with risk factors for schistosomiasis with anti-schistosomal antibody levels. Although there is no robust evidence to suggest a specific management of Sch-PAH, Phosphodiesterase −5 inhibitors (PDE-i) have been shown to improve functional capacity, 6-min walk test, and an improvement in cardiac index. There is some evidence that treatment of underlying infection, if never been considered may have some benefit in the management of Sch-PAH.