Can Anti-Tuberculosis Therapy Cause Tenosynovitis?
Yes, anti-tuberculosis therapy can cause tenosynovitis, specifically isoniazid has been documented to induce this adverse effect, though it is rare. 1
Direct Drug-Induced Tenosynovitis
The most relevant evidence comes from documented cases of isoniazid-induced tenosynovitis confirmed by MRI imaging. In these cases, patients developed tenosynovitis 1 month after starting standard anti-TB treatment, with symptoms including:
- Hand edema and swelling
- Arthralgia
- Difficulty grasping
- Limited finger flexion
- Hypesthesia
The key diagnostic feature is that symptoms improved after discontinuing isoniazid, and in one case an isoniazid challenge test confirmed the drug as the causative agent 1. This represents a true drug-induced adverse effect rather than paradoxical reaction.
Clinical Recognition
This adverse effect may be significantly underestimated because:
- Severity is variable
- Symptoms are nonspecific
- It is not listed among the "most important adverse reactions" in major TB treatment guidelines 2, 3, 2
The British Thoracic Society and CDC guidelines extensively detail adverse reactions to anti-TB drugs but do not specifically mention tenosynovitis, focusing instead on peripheral neuropathy from isoniazid, hepatotoxicity, and visual toxicity from ethambutol 2, 3.
Paradoxical Inflammatory Tenosynovitis
A separate mechanism exists where paradoxical inflammatory reactions can cause or worsen tenosynovitis during or after completing anti-TB treatment 4. This represents immune reconstitution rather than direct drug toxicity and can occur:
- During treatment (more common with concurrent antiretroviral therapy in HIV patients)
- Even 1 month after completing a full 9-month course 4
- Presents with recurrent swelling, lymphadenopathy
- Responds to corticosteroid therapy
This paradoxical reaction is well-documented in TB treatment guidelines as occurring in 7.6% of HIV-coinfected patients, though typically manifests as fever, lymphadenopathy, and worsening pulmonary infiltrates rather than isolated tenosynovitis 5.
Clinical Approach
When tenosynovitis develops during anti-TB treatment:
- Timing matters: Onset within 1-2 months suggests drug-induced etiology 1
- Consider MRI to confirm tenosynovitis and assess severity
- If isoniazid-induced is suspected: Discontinue isoniazid and observe for improvement
- If paradoxical reaction: Rule out treatment failure or drug resistance first, then consider corticosteroids 5, 4
Key Caveat
Do not confuse drug-induced tenosynovitis with tuberculous tenosynovitis itself—a rare form of extrapulmonary TB that presents with chronic progressive swelling, rice bodies on imaging, and granulomatous inflammation on histopathology 6, 7, 8. This requires anti-TB treatment rather than drug discontinuation.
The distinction is critical: Drug-induced tenosynovitis improves with isoniazid cessation, while tuberculous tenosynovitis requires continuation of anti-TB therapy with possible surgical intervention.