Abstract
Laryngeal tuberculosis (LTB) represents a rare but clinically significant manifestation of extra-pulmonary tuberculosis (EPTB). Though pulmonary tuberculosis (PTB) remains the most common form, involvement of the larynx can lead to diagnostic challenges due to its nonspecific symptoms and resemblance to other laryngeal diseases such as chronic laryngitis or carcinoma. This article provides a comprehensive overview of the prevalence, pathogenesis, clinical presentation, diagnostic approaches, and management strategies for laryngeal tuberculosis, highlighting the importance of early detection and multidisciplinary care to prevent complications and transmission.
Introduction
Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains one of the leading infectious diseases worldwide, with millions of new cases reported annually. Although the pulmonary form is predominant, extra-pulmonary tuberculosis (EPTB) accounts for approximately 15–20% of all TB cases, involving organs other than the lungs such as lymph nodes, bones, meninges, and the larynx. Laryngeal tuberculosis is one of the least frequent yet most clinically significant forms of EPTB due to its potential to mimic malignancy and its role in disease transmission through sputum and aerosolized particles.
Historically, laryngeal tuberculosis was common in advanced pulmonary TB cases. However, recent studies indicate a shift in clinical presentation, with many patients showing isolated laryngeal involvement or mild pulmonary findings. This changing pattern underscores the importance of heightened clinical awareness among otolaryngologists and pulmonologists.
Pathophysiology
Laryngeal tuberculosis can occur through two main mechanisms:
- Direct spread of infection from pulmonary lesions via expectorated sputum containing M. tuberculosis.
- Hematogenous dissemination, leading to isolated primary laryngeal involvement without lung pathology.
The most commonly affected areas are the vocal cords, epiglottis, arytenoids, and posterior commissure due to their exposure to infectious droplets and rich lymphatic drainage. Chronic inflammation results in granuloma formation, mucosal ulceration, and fibrosis, often leading to hoarseness and airway compromise.
Clinical Presentation
Symptoms of laryngeal tuberculosis can be insidious and nonspecific, often mimicking chronic laryngitis or laryngeal carcinoma. Common symptoms include:
- Hoarseness of voice (most frequent)
- Sore throat and dysphagia
- Cough and hemoptysis
- Pain during phonation (odynophonia)
- Dyspnea or stridor in advanced cases
- Constitutional symptoms such as fever, weight loss, and night sweats
In a study by Iqbal et al. (2024), laryngitis accounted for 22.58% of ENT symptoms in extra-pulmonary TB patients, with a significant association observed between smoking and laryngitis (p=0.033), suggesting that smoking may exacerbate mucosal vulnerability.
Diagnosis
The diagnosis of laryngeal tuberculosis requires a combination of clinical suspicion, endoscopic findings, microbiological tests, and imaging studies.
- Laryngoscopy:
Typical findings include ulcerations, nodular or polypoid lesions, diffuse mucosal edema, and granulation tissue, especially on the vocal cords or epiglottis. Direct laryngoscopy allows for visual assessment and biopsy sampling. - Histopathology:
Biopsy remains the gold standard, showing granulomatous inflammation with caseation necrosis and Langhans giant cells. Acid-fast bacilli (AFB) staining and polymerase chain reaction (PCR) help confirm Mycobacterium tuberculosis. - Imaging Studies:
Chest X-rays or CT scans may reveal concomitant pulmonary lesions. However, in isolated LTB, imaging may appear normal. MRI of the neck can delineate soft tissue involvement. - Microbiological Tests:
- Sputum examination for AFB
- Mycobacterial culture
- GeneXpert MTB/RIF assay for rapid diagnosis and rifampicin resistance detection
- Differential Diagnosis:
It is critical to differentiate LTB from laryngeal carcinoma, chronic laryngitis, fungal infections, and sarcoidosis due to overlapping symptoms.
Management and Treatment
The cornerstone of treatment for laryngeal tuberculosis is anti-tubercular therapy (ATT), following the standard World Health Organization (WHO) and national TB control program guidelines.
Standard Regimen (6 months):
- Intensive Phase (2 months): Isoniazid, Rifampicin, Pyrazinamide, Ethambutol
- Continuation Phase (4 months): Isoniazid, Rifampicin
Supportive therapy includes voice rest, hydration, and corticosteroids in selected cases to reduce inflammation. Surgical intervention is reserved for airway obstruction or residual laryngeal scarring after medical treatment.
Treatment Response:
Most patients show improvement within weeks of therapy, with full resolution of symptoms and mucosal healing in 3–6 months. Persistent hoarseness may occur due to fibrosis or vocal cord scarring.
Complications
If untreated or misdiagnosed, laryngeal tuberculosis can result in:
- Airway obstruction
- Permanent vocal cord damage
- Laryngeal stenosis
- Dissemination to other organs
- Ongoing transmission due to delayed treatment
Thus, early recognition and management are essential to prevent morbidity and transmission.
Public Health and Preventive Aspects
Laryngeal tuberculosis poses a public health concern because patients can remain infectious during vocalization. Preventive strategies include:
- Early detection and treatment of pulmonary TB
- Isolation during the infectious phase
- Use of N95 masks for healthcare workers
- Health education on the dangers of smoking and untreated cough
Conclusion
Laryngeal tuberculosis remains a diagnostic challenge due to its rarity and overlapping symptoms with other laryngeal disorders. Clinicians should maintain a high index of suspicion, especially in patients presenting with persistent hoarseness, weight loss, and a history of tuberculosis. Early diagnosis through endoscopy and histopathology, combined with timely anti-tubercular therapy, ensures complete recovery and prevents long-term complications. Multidisciplinary collaboration between ENT specialists, pulmonologists, and infectious disease experts is vital for successful management.
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