Which side of the body is more commonly affected in tuberculosis (TB)?

Tuberculosis More Commonly Affects the Right Side of the Body

Tuberculosis (TB) most commonly affects the right side of the body, particularly in pulmonary and extrapulmonary manifestations. This anatomical predilection is important to understand for clinical diagnosis and management of TB.

Anatomical Distribution of Tuberculosis

Pulmonary Tuberculosis

• Right lung involvement is more common in pulmonary TB due to the anatomical structure of the bronchial tree
• The right main bronchus is wider, shorter, and more vertical than the left, facilitating easier access of inhaled pathogens 1
• Apical and posterior segments of the upper lobes (particularly the right) are classic sites for reactivation TB

Extrapulmonary Tuberculosis

• In abdominal TB, the ileocecal region (right side) and terminal ileum are the most common sites of involvement 2
• Right-sided pleural effusions are more commonly seen in TB compared to left-sided effusions
• Musculoskeletal TB shows a predilection for the right side in many presentations 3

Clinical Implications

Diagnostic Considerations

• When evaluating patients with suspected TB, clinicians should have a higher index of suspicion for right-sided manifestations
• Radiological examinations should pay particular attention to right-sided findings:
  • Right upper lobe infiltrates in pulmonary TB
  • Right-sided pleural effusions
  • Right-sided lymphadenopathy

Treatment Approach

• The side predilection doesn't alter the standard treatment approach
• Standard TB treatment consists of:
  • Initial intensive phase (2 months): isoniazid, rifampicin, pyrazinamide, and ethambutol
  • Continuation phase (4 months): isoniazid and rifampicin 2
• For extrapulmonary TB, treatment duration may be extended to 6-9 months depending on the site 2

Special Considerations

Abdominal Tuberculosis

• The ileocecal region (right side) is the most common site of extrapulmonary TB 2
• Complications in this region include obstruction due to narrowing of the lumen and perforation in ulcerative types 2
• Surgical management may be required for complications, with resection and anastomosis preferred over primary closure for perforations 2

Genitourinary Tuberculosis

• Genitourinary TB accounts for approximately 4.6% of extrapulmonary TB cases in the EU 2
• Kidney is the most common genitourinary organ affected, with right-sided predominance in many case series 4
• Patients typically present with non-specific symptoms including hematuria, increased urinary frequency, and abdominal/lumbar pain 2

Pitfalls and Caveats

• The right-sided predominance is a general trend and not an absolute rule; TB can affect either side
• Bilateral involvement is common, especially in advanced disease
• In immunocompromised patients (particularly those with HIV), the classic anatomical distribution may be altered with more diffuse or atypical presentations 2, 5
• Diagnosis should not be excluded based solely on the affected side if other clinical features suggest TB

Understanding the right-sided predominance of TB can help clinicians maintain appropriate suspicion when evaluating patients with unilateral findings, potentially leading to earlier diagnosis and improved outcomes.