Broncholithiasis

Broncholithiasis is the presence of calcified material within or eroding into the bronchial lumen, usually from a calcified peribronchial lymph node. The usual causes are healed granulomatous infection: histoplasmosis in endemic regions, tuberculosis (very relevant in Africa), and less often silicosis, coccidioidomycosis and sarcoidosis.

It occurs at any age, and the right middle lobe and the subcarinal and hilar regions are the usual sites. It can lead to haemoptysis, obstruction and fistula.

Pathophysiology. A calcified node erodes through the wall of the adjacent bronchus, or lies against it, and the stone either extrudes into the lumen or distorts and obstructs it. Obstruction leads to atelectasis, post-obstructive pneumonia and bronchiectasis. Erosion into vessels can cause severe bleeding, and fistulas can open into the oesophagus, pleura or aorta.

Chronic cough, wheeze, recurrent pneumonia, chest pain, and haemoptysis (up to 20% have massive bleeding). Lithoptysis, the coughing up of stone fragments, is the only specific feature, and occurs in a minority.

Massive haemoptysis (over 200 mL in 24 hours or any haemodynamic instability), signs of a fistula (cough on swallowing, bleeding, sepsis) and acute airway obstruction need emergency care.

• CT chest, without and with contrast: calcified lymph node in contact with or inside a bronchus, with distal atelectasis, air trapping, bronchiectasis or consolidation. This is the investigation of choice.
• Bronchoscopy to view the stone and to assess mobility, with caution and a plan for bleeding, since forceful removal of a stone that is embedded can cause fatal haemorrhage.
• Tests for the original cause: tuberculin or interferon gamma release test, sputum for acid fast bacilli and culture (including cartridge based nucleic acid test), Histoplasma antigen and serology.
• Barium swallow or CT when an oesophageal fistula is suspected.

Differential diagnosis.

• Inhaled foreign body
• Endobronchial tumour, such as carcinoid
• Tracheobronchial amyloidosis
• Calcified granuloma not in contact with the airway
• Endobronchial tuberculosis
• Bronchiectasis from other causes

• Active tuberculosis is treated first: 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 daily for 4 months, with pyridoxine 10 to 25 mg daily. Adjust for renal or liver disease and drug resistance.
• Loose stones lying free in the lumen: flexible or rigid bronchoscopic removal, with surgical backup and bronchial artery embolisation available.
• Stones partly embedded or with vascular or fistula risk: thoracic surgery (thoracotomy or video assisted) with removal of the stone and the node, with bronchoplasty, sleeve or lobar resection for damaged lung. A fistula to the oesophagus or aorta requires surgical repair.
• Haemoptysis: lie the patient bleeding side down, give oxygen, and tranexamic acid 1 g intravenously (then 1 g every 8 hours) or nebulised 500 mg three times daily. Bronchial artery embolisation for persistent or massive bleeding, and rigid bronchoscopy for airway protection.
• Infection beyond the obstruction: amoxicillin-clavulanate 625 mg three times daily for 7 to 10 days, adjusted to cultures.
• Asymptomatic, small stones found on CT are observed.

Complications and prognosis. Massive haemoptysis, post-obstructive pneumonia, bronchiectasis, and fistula. Outcome is good with timely surgery, and the disease is not malignant.

Monitoring. Clinical and chest imaging review at 3 and 12 months after removal or surgery, and follow up of tuberculosis treatment.

Referral and escalation. Refer to a thoracic surgeon and interventional pulmonologist at diagnosis, and refer as an emergency for haemoptysis or airway obstruction.