Bilharzial cor pulmonale

Bilharzial cor pulmonale is a rare and severe form of pulmonary hypertension resulting from chronic infection with the parasitic worms of the genus Schistosoma, commonly referred to as bilharzia or schistosomiasis. This condition represents a specific manifestation of schistosomal infection affecting the pulmonary circulation and right side of the heart. It is characterized by the development of pulmonary hypertension (high blood pressure in the lungs' arteries), leading to right heart failure, known as cor pulmonale.

Etiology and Pathophysiology

The primary cause of bilharzial cor pulmonale is chronic infection with Schistosoma species, particularly Schistosoma mansoni and Schistosoma japonicum. These parasites are transmitted to humans through contact with contaminated freshwater, where infected snails release larval forms of the parasite. Once in the human body, the parasites mature and lay eggs, some of which are excreted in feces or urine to continue the cycle, while others become trapped in body tissues, causing immune reactions and progressive damage.

In the case of bilharzial cor pulmonale, the eggs lodge in the small vessels of the lungs, leading to inflammation, fibrosis, and obstruction of pulmonary arterioles. This results in increased resistance to blood flow through the lungs, causing pulmonary hypertension. The right ventricle of the heart must work harder to pump blood against this increased resistance, leading to hypertrophy (thickening of the heart muscle) and eventually right heart failure (cor pulmonale).

Clinical Features

Patients with bilharzial cor pulmonale may initially be asymptomatic or present with symptoms related to schistosomiasis, such as abdominal pain, diarrhea, and blood in the stool. As pulmonary hypertension develops, symptoms may include:

• Shortness of breath, especially on exertion
• Fatigue
• Chest pain
• Palpitations
• Swelling of the legs and abdomen due to fluid accumulation (edema)
• Cyanosis (bluish discoloration of the skin and mucous membranes due to low oxygen levels)

Diagnosis

Diagnosis of bilharzial cor pulmonale involves a combination of clinical assessment, imaging studies, and laboratory tests, including:

• Echocardiography to assess pulmonary hypertension and right ventricular function
• Chest X-ray to look for signs of heart enlargement and pulmonary changes
• Pulmonary function tests to evaluate the impact on lung function
• Blood tests to detect antibodies against Schistosoma species
• Stool and urine tests to identify schistosome eggs

Treatment

Treatment of bilharzial cor pulmonale focuses on managing pulmonary hypertension and treating the underlying schistosomiasis infection. This may include:

• Antiparasitic therapy with praziquantel to kill the schistosome worms
• Medications to reduce pulmonary hypertension, such as endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and prostacyclin analogs
• Diuretics to manage fluid accumulation
• Oxygen therapy for patients with low blood oxygen levels
• In severe cases, heart-lung transplantation may be considered

Prevention

Prevention of bilharzial cor pulmonale involves controlling schistosomiasis through public health measures, such as improving sanitation, providing access to clean water, and snail control programs. Education on avoiding contact with contaminated water and mass treatment programs with praziquantel in endemic areas are also crucial.

Conclusion

Bilharzial cor pulmonale is a serious and potentially life-threatening condition resulting from chronic schistosomiasis infection. Early diagnosis and treatment of schistosomiasis and pulmonary hypertension are essential to prevent the progression to cor pulmonale and improve outcomes for affected individuals.