Pleurocutaneous Fistula

Pleurocutaneous fistula is a chronic sinus tract between the pleural space and the skin of the chest wall, discharging pus, fluid or air. It is a rare complication of chronic pleural infection and chest wall disease.

Causes are chronic empyema (the commonest), tuberculosis, actinomycosis and nocardiosis, previous chest drain or thoracotomy (post-surgical infection, rib osteomyelitis, retained foreign body such as a sponge or suture), trauma, radiotherapy and malignancy invading the chest wall. In tuberculosis endemic areas, tuberculous empyema is a leading cause.

Pathophysiology. A persistent pleural infection or cavity erodes through the parietal pleura and intercostal tissues, along a drain track or rib osteomyelitis, to the skin. The tract stays open because of infection, a rigid pleural cavity that cannot collapse, foreign material or necrotic bone, and poor drainage.

A chronically discharging wound or sinus on the chest wall, often with a history of drain, surgery or tuberculosis. Discharge may be purulent, serous or contain air when coughing. Fever, malaise, weight loss, local pain, redness or a fluctuant mass can be present. Examination shows a sinus opening, local induration and sometimes a dull chest.

Spreading cellulitis, sepsis or large air or pus discharge with respiratory compromise needs urgent assessment.

• Clinical examination of the sinus, and exclusion of an unrelated cutaneous sinus.
• Sinogram (contrast injected through the sinus) or CT with contrast showing the tract, the pleural cavity, rib destruction and foreign body.
• Culture of discharge for bacteria (including anaerobes), mycobacteria (smear, culture and nucleic acid test), fungi and Actinomyces and Nocardia (prolonged culture and sulphur granules on microscopy).
• Biopsy of the tract wall for histology and tissue cultures, particularly for malignancy, tuberculosis and actinomycosis.
• Blood tests: full blood count, C-reactive protein, albumin, glucose control, and HIV test.
• Bronchoscopy if a bronchopleural fistula is suspected (air or tidal drainage).
• Chest radiograph for rib changes and lung disease.

Differential diagnosis.

• Empyema necessitans
• Chest wall abscess or osteomyelitis (without pleural involvement)
• Tuberculous or fungal sinus
• Malignant chest wall invasion
• Retained foreign body
• Hidradenitis or other cutaneous sinus

• Treat infection by organism: for tuberculosis, rifampicin 10 mg/kg (maximum 600 mg), isoniazid 5 mg/kg (maximum 300 mg), pyrazinamide 25 mg/kg and ethambutol 15 mg/kg daily for 2 months, then rifampicin and isoniazid for 4 months (extended to 9 to 12 months in extensive disease), with pyridoxine 10 to 25 mg daily. For actinomycosis, benzylpenicillin 18 to 24 million units daily intravenously for 2 to 6 weeks, then amoxicillin 1 g three times daily for 6 to 12 months. For nocardiosis, co-trimoxazole (trimethoprim 5 to 10 mg/kg daily in 2 to 4 divided doses) for 6 to 12 months. For pyogenic infection, amoxicillin-clavulanate 625 mg three times daily or intravenous co-amoxiclav 1.2 g three times daily, with culture directed changes.
• Drainage of the pleural cavity by an adequately placed chest drain, with irrigation as needed.
• Surgery is often needed: debridement of infected bone and tissue, removal of foreign body, decortication, open window thoracostomy (Eloesser flap or Clagett procedure) with muscle or omental flap closure, and closure of the tract. Negative pressure wound therapy supports healing.
• Nutrition (protein 1.2 to 1.5 g/kg daily), control of diabetes, smoking cessation and treatment of HIV.
• Dressings and wound care to protect the skin and manage discharge.
• Malignancy: oncology review for resection, radiotherapy or systemic therapy.

Complications and prognosis. Chronic sepsis, rib osteomyelitis, secondary amyloidosis, malnutrition and skin cancer in a long standing sinus. Healing is good when infection is eradicated and the cavity is obliterated.

Monitoring. Weekly wound review early, repeat imaging at 4 to 6 weeks, and microbiological and inflammatory markers during therapy.

Referral and escalation. Refer to thoracic surgery and an infectious diseases or tuberculosis service.