B58.3 Pulmonary toxoplasmosis

Name of the Condition

• Pulmonary toxoplasmosis

Summary

Pulmonary toxoplasmosis is a respiratory manifestation of infection with the protozoan parasite Toxoplasma gondii. It involves inflammation of the lungs and may present as an acute or chronic condition. Clinical severity varies based on the host's immune status and the extent of pulmonary involvement. While often asymptomatic in immunocompetent individuals, it can cause significant respiratory symptoms in immunocompromised patients or those with congenital infection.

Causes

The condition is caused by Toxoplasma gondii, a parasite that can infect pulmonary tissues through congenital transmission or reactivation of latent infection. Transmission occurs via ingestion of contaminated food or water, contact with cat feces containing oocysts, or consumption of undercooked meat harboring tissue cysts. In the lungs, the parasite can invade alveolar and interstitial tissues, triggering inflammatory responses that may lead to pneumonitis or respiratory distress.

Risk Factors

• Immunocompromised states, such as HIV/AIDS, organ transplantation, or chemotherapy.
• Congenital infection acquired from an infected mother during pregnancy.
• Exposure to cat feces or contaminated soil.
• Consumption of undercooked or raw meat, particularly pork, lamb, or venison.
• Advanced age or systemic immunosuppression.

Symptoms

• Cough (often dry or productive)
• Shortness of breath or dyspnea
• Fever
• Chest pain
• Fatigue
• In severe cases, respiratory failure may occur.

Diagnosis

Diagnosis typically involves a combination of clinical evaluation, imaging studies (e.g., chest X-ray or CT scan showing pulmonary infiltrates), and laboratory testing. Serologic tests for Toxoplasma gondii antibodies may support the diagnosis, while tissue biopsy or bronchoalveolar lavage with PCR or histopathology can confirm the presence of the parasite. Differential diagnosis includes other infectious or non-infectious causes of pneumonitis.

Treatment Options

Treatment depends on the patient's immune status and severity of disease. For immunocompetent individuals with mild symptoms, supportive care may suffice. Immunocompromised patients or those with severe disease typically require antiparasitic therapy, such as pyrimethamine combined with sulfadiazine or clindamycin. Corticosteroids may be used to manage inflammation in select cases. Duration of therapy is guided by clinical response and immune status.

Prognosis and Follow-Up

Prognosis varies based on the patient's immune status and timeliness of treatment. Immunocompetent individuals generally have a favorable outcome with appropriate therapy. Immunocompromised patients or those with severe disease may experience prolonged recovery or complications. Follow-up includes monitoring for symptom resolution, repeat imaging if needed, and ongoing assessment of immune function. Lifelong suppressive therapy may be necessary for high-risk patients.

Complications

• Respiratory failure requiring mechanical ventilation
• Disseminated toxoplasmosis involving other organs
• Chronic lung damage or fibrosis
• Recurrence of infection in immunocompromised patients
• Increased risk of secondary infections.

Lifestyle & Prevention

• Cook meat thoroughly to an internal temperature of at least 145°F (63°C).
• Wash hands thoroughly after handling raw meat or soil.
• Avoid contact with cat feces, and delegate litter box cleaning to others if possible.
• Wear gloves when gardening or handling soil.
• Ensure proper food and water safety, especially when traveling to endemic areas.

When to Seek Professional Help

Seek immediate medical attention if you experience severe shortness of breath, chest pain, high fever, or signs of respiratory distress. Prompt evaluation is critical for immunocompromised individuals or those with a history of toxoplasmosis exposure, as early treatment can prevent complications.

Tips for Medical Coders

When coding pulmonary toxoplasmosis (B58.3), ensure documentation supports the respiratory manifestation and differentiates it from other toxoplasmosis sites. Verify the presence of pulmonary symptoms or imaging findings consistent with the condition. For immunocompromised patients, note the underlying cause (e.g., HIV, transplant) as it may impact coding and reporting. Accurate documentation of the infection's location and clinical course is essential for appropriate code assignment.