Complications of Tuberculosis — Complete MD Exam Guide

Classification Overview

A. Pulmonary Complications

1. Hemoptysis

• Most common cause of massive hemoptysis in developing countries — always suspect TB.
• Mechanisms:
  • Rasmussen's aneurysm — mycotic aneurysm of a branch of the pulmonary artery within a TB cavity wall; rupture → massive, potentially fatal hemoptysis.
  • Ulceration/erosion of bronchial vessels in cavitary disease.
  • Aspergilloma in a residual cavity (see below).
• Management: bronchial artery embolization (BAE) is the intervention of choice for massive hemoptysis; surgical resection if BAE fails.

2. Pneumothorax

• Rupture of a subpleural caseating focus or cavity into the pleural space.
• May be spontaneous or occur during cough.
• Tension pneumothorax is a medical emergency.

3. Cavitation

• Hallmark of post-primary TB (especially upper lobe apices — Simon's foci).
• Cavities promote:
  • Superinfection (aspergilloma, Aspergillus fumigatus).
  • Ongoing airway dissemination.
  • Bronchiectasis.
  • Hemoptysis.

4. Bronchiectasis

• Permanent dilatation of bronchi from destruction of bronchial walls during TB.
• Produces chronic productive cough, recurrent infections, and hemoptysis.

5. Aspergilloma (Fungus Ball)

• Aspergillus fumigatus colonizes a residual healed TB cavity.
• Radiologically: "air crescent sign" — a crescentic opacity around a rounded fungal mass, moves with posture change ("rolling ball").
• Presents with hemoptysis (sometimes massive), cough, weight loss.
• Treatment: itraconazole; surgical excision if recurring massive hemoptysis.

6. Destroyed Lung (Vanishing Lung)

• Extensive parenchymal destruction in one or both lungs after severe TB.
• Severe restrictive ± obstructive defect.
• Leads to cor pulmonale and chronic respiratory failure.

7. Cor Pulmonale & Pulmonary Hypertension

• Results from:
  • Extensive parenchymal destruction → reduced pulmonary vascular bed.
  • Hypoxic pulmonary vasoconstriction.
  • Fibrothorax causing restrictive mechanics.
• Presents as right heart failure (elevated JVP, pedal edema, hepatomegaly).

8. Laryngeal TB

• Extension from sputum-laden secretions.
• Presents with hoarseness, dysphagia.
• Most infectious form of TB — organism-laden droplets from vocal cords.

B. Pleural Complications

1. Pleural Effusion (Tuberculous Pleuritis)

• ~20% of all extrapulmonary TB cases (Digestive Tract TB, p. 4).
• Exudative lymphocytic effusion; ADA (adenosine deaminase) elevated >40 IU/L is highly suggestive.
• Usually unilateral; self-limiting but can lead to fibrothorax if untreated.
• Pleural biopsy has highest diagnostic yield (~70–80%).

2. Tuberculous Empyema

• Less common; results from rupture of a cavity with massive spillage of organisms into the pleural space (Harrison's 21st ed., p. 5135).
• May create a bronchopleural fistula — air in the pleural space → hydropneumothorax on CXR (air-fluid level).
• Fluid: purulent, thick, lymphocyte-rich; AFB smear and culture often positive.
• Requires surgical drainage in addition to chemotherapy.
• Outcome: severe pleural fibrosis → restrictive lung disease.
• Decortication (removal of thickened visceral pleura) may be needed to restore lung function (Harrison's 21st ed., p. 5135).

3. Fibrothorax

• End result of chronic pleural inflammation.
• Thick fibrous peel traps the lung → severe restriction of ventilation.
• Treated by decortication.

C. Extrapulmonary Complications

The most common site of EPTB is lymph nodes (both HIV+ and HIV−). (Digestive Tract TB, p. 4)

1. Lymphadenitis (Scrofula)

• Cervical lymph nodes most commonly involved (posterior triangle).
• Characteristic: matted, non-tender nodes; may form cold abscess (collar-stud abscess penetrating deep cervical fascia).
• Diagnosis: FNAC or excision biopsy — caseating granuloma.

2. TB Meningitis (TBM)

• Most serious form of EPTB; high mortality and morbidity.
• Pathology: Rich focus — subependymal/subarachnoid tubercle ruptures into CSF.
• CSF findings:
  • Appearance: clear/xanthochromic
  • Cells: lymphocytes (10–400/mm³)
  • Protein: markedly elevated (>100 mg/dL)
  • Glucose: low (<45 mg/dL, CSF:serum ratio <0.5)
  • AFB smear: low yield; culture gold standard
• Complications of TBM: hydrocephalus (communicating > obstructive), cranial nerve palsies (II, III, VI, VII most common), vasculitis → stroke, cerebral infarction, arachnoiditis, seizures.
• Treatment: 2HRZE/10HR + dexamethasone (reduces mortality regardless of severity).

3. Miliary TB

• Hematogenous dissemination forming 1–2 mm "millet seed" lesions uniformly throughout lungs and organs.
• CXR: miliary nodules — discrete, uniform, 1–2 mm, bilateral, diffuse ("snowstorm appearance").
• Clinical: fever, hepatosplenomegaly, choroidal tubercles (pathognomonic — seen on fundoscopy), pancytopenia (bone marrow involvement), SIADH, adrenal insufficiency.
• Choroidal tubercles on fundoscopy = pathognomonic of miliary TB.

4. Pott's Disease (Spinal TB)

• Most common skeletal manifestation.
• L1–L2 most common level; thoracic spine (T10–L2) most common overall.
• Pathology: starts in anterior aspect of vertebral body (paradiscal) → disc destruction → collapse → gibbus deformity (sharp angular kyphosis).
• Cold (psoas) abscess: tracks along psoas sheath to iliac fossa — presents as fluctuant groin swelling.
• Pott's paraplegia: compression of spinal cord by abscess/granulation tissue/collapsed vertebra → paraplegia (most feared complication).
• Diagnosis: MRI spine (investigation of choice), CT-guided biopsy.

5. Tuberculous Pericarditis

• Presents as pericardial effusion → cardiac tamponade (Beck's triad: hypotension, elevated JVP, muffled heart sounds).
• Chronic: constrictive pericarditis — calcified pericardium on CXR; Kussmaul's sign; pericardial knock.
• Treatment: anti-TB drugs + corticosteroids; pericardiectomy for constrictive pericarditis.

6. Adrenal TB (Addison's Disease)

• Bilateral adrenal destruction by TB — classic cause of primary adrenal insufficiency (Addison's disease).
• Features: hyperpigmentation, hypotension, hyponatremia, hyperkalemia, eosinophilia.
• Adrenal calcification on plain X-ray is a hallmark.

7. Genitourinary TB (GUTB)

• 10–15% of all EPTB in the US (Digestive Tract TB, p. 4).
• Renal TB: "sterile pyuria" — pus cells in urine with negative routine culture; never miss TB in sterile pyuria.
• Complications: ureteric stricture → hydronephrosis, autonephrectomy (calcified, non-functioning kidney), infertility.
• Female: salpingitis, endometritis → infertility, amenorrhea.
• Male: epididymo-orchitis (beaded vas deferens).

8. Gastrointestinal TB

• 2.5% of EPTB in the US (Digestive Tract TB, p. 4).
• Ileocaecal junction — most common site (due to lymphoid tissue, slow transit, alkaline pH).
• Complications: intestinal obstruction, perforation, malabsorption, fistulae, peritonitis.
• "Dough-pipe colon" on barium enema — chronic GI TB.

9. Peritoneal TB

• Presents as ascites (exudate, lymphocytic, elevated ADA).
• Complications: bowel obstruction, adhesions.

10. Ocular TB

• Choroidal tubercles (miliary TB), uveitis, optic neuritis, retinal vasculitis.

D. Treatment-Related Complications

Anti-TB Drug Toxicity

Immune Reconstitution Inflammatory Syndrome (IRIS)

• Occurs in HIV co-infected patients on ART initiated during TB treatment.
• Paradoxical IRIS: worsening of existing TB lesions — fever, lymphadenopathy, new infiltrates.
• Unmasking IRIS: previously subclinical TB becomes clinically apparent after immune recovery.
• Management: NSAIDs; corticosteroids for severe cases; continue ART and anti-TB drugs.

E. Complications in Special Populations

F. High-Yield Exam Mnemonics

G. Summary Diagram — Complications by System

TUBERCULOSIS
├── PULMONARY
│   ├── Hemoptysis → Rasmussen's aneurysm
│   ├── Pneumothorax → Tension pneumothorax
│   ├── Cavitation → Aspergilloma
│   ├── Bronchiectasis
│   ├── Destroyed lung
│   └── Cor pulmonale
├── PLEURAL
│   ├── Pleural effusion (exudate, lymphocytic)
│   ├── Empyema → Bronchopleural fistula
│   └── Fibrothorax → Restrictive disease
├── EXTRAPULMONARY
│   ├── Lymphadenitis (scrofula, collar-stud abscess)
│   ├── Meningitis → Hydrocephalus, stroke, CN palsies
│   ├── Miliary TB → Choroidal tubercles
│   ├── Pott's spine → Gibbus, psoas abscess, paraplegia
│   ├── Pericarditis → Tamponade, constrictive pericarditis
│   ├── Adrenal (Addison's disease)
│   ├── Genitourinary → Sterile pyuria, infertility
│   └── GI → Ileocaecal obstruction, perforation
└── TREATMENT
    ├── Drug toxicity (hepatotoxicity, optic neuritis, neuropathy)
    └── IRIS (HIV patients)

Open Negative Syndrome in Tuberculosis

Definition

An open (communicating) pulmonary cavity on imaging — BUT sputum AFB smear and culture are repeatedly negative

How It Occurs — Pathophysiology

Clinical Significance

1. Not necessarily inactive disease — An open negative cavity does not always mean the TB is cured. The cavity may:
   • Still harbor viable but dormant bacilli (risk of reactivation)
   • Act as a source of aspergilloma formation
   • Cause hemoptysis from Rasmussen's aneurysm or aspergilloma even without active TB
2. Epidemiological concern — The patient is usually non-infectious (smear negative), but cannot be completely cleared of risk until cavity is confirmed sterile by repeated cultures over time.
3. Surgical relevance — Persistent open negative cavities after completed treatment may require surgical resection (lobectomy/pneumonectomy) if:
   • Recurrent massive hemoptysis
   • Superimposed aspergilloma
   • Risk of reactivation in an immunocompromised patient

Diagnosis

• CXR / HRCT chest: demonstrates residual cavity with patent bronchial communication (air-fluid level absent; wall may be thin and fibrous)
• Sputum AFB smear × 3: negative on at least 3 consecutive samples
• Sputum culture (LJ medium / MGIT): negative
• Bronchoscopy + BAL: may be performed to exclude active disease or secondary infection
• Serology/IGRA: not useful for distinguishing active vs. inactive

Differentiation from Similar Concepts

Key Exam Points

• The cavity remains because fibrosis has replaced the caseous center — it does not collapse due to the rigid fibrotic wall.
• Open negative syndrome is a common cause of aspergilloma — the sterile cavity provides ideal anaerobic, protein-rich environment for Aspergillus colonization.
• Always rule out MDR-TB before labeling as open negative — resistant strains may not grow on standard culture media or at low loads.
• In examinations: if a question describes a TB patient with a residual cavity + negative sputum + hemoptysis → think open negative syndrome with superimposed aspergilloma.