• Over 1/3 of world's population is infected

Infection Types

  • Primary Infection
    • Usually contained by body via formation of tubercles
    • Hematogenous spread limited to areas with high O2 or blood flow (apical lung, vertebrae)
      • PPD positive
  • Reactivation Infection
    • More common in immunocompromised patients (AIDS, malignancy, DM, immunosupressive medications)
  • Miliary Tuberculosis
    • Disseminated tuberculosis
    • Looks like millet seeds
    • Seen in patients with comorbid AIDS
      • Check HIV in patients suspected of TB
    • PPD is positive in only 50% of cases

Special Populations

  • AIDS
    • TB is 200-500x more common in AIDS population than general population
    • CD4 count
      • Increased risk when <500
      • Determines the clinical and radiographic presentations of TB
  • Pediatric
    • More likely to progress early to active disease
      • Presentation more commonly that of primary TB
    • >5yr - classic symptoms
    • <5yr - miliary TB, meningitis, cervical lymphadenitis, pneumonia that does not respond to usual antibiotics
    • Children are usually not infectious due to their weak cough

Tuberculin Skin Test

Used for population screening, but not for rule-out in patients with concern for active disease

Reaction considered positive in following situations:

  • >5 mm
    • HIV positive
    • Close contact with active TB patient
    • Nodular or fibrotic changes on CXR
    • Immunosuppressed (TNF-alpha inhibitor, chemo, organ transplant)
  • >10 mm
    • Children < 4 yrs old
    • Healthcare/lab/prison employees and residents
    • Co-morbid conditions (dialysis, DM, blood/head/neck/lung malignancy, IV drug users)
    • People from high prevalence areas
  • >15 mm
    • Persons with no known risk factors for TB

Clinical Features

Primary Tuberculosis

  • Usually asymptomatic (only identified by positive PPD/quantiferon gold)
  • May be rapidly progressive and fatal in immunocompromised patients
    • Fever, malaise, weight loss, chest pain
  • Tuberculous pleural effusion may occur if subpleural node ruptures into the pleura
    • Pleuritic chest pain
    • Exudative fluid
      • Organisms may not be visible on acid-fast staining (need pleural biopsy)

Reactivation Tuberculosis

  • Pulmonary: Productive cough, hemoptysis, dyspnea, pleuritic chest pain
  • Systemic: Fever, night sweats, malaise, fatigue, weight loss
  • Extrapulmonary
    • Painless lymphadenopathy/scrofula (most common extrapulmonary manifestation)
    • Pericarditis
    • Peritonitis
    • Meningitis
    • Adrenal insufficiency
      • If adrenals affected, TB typically spreads to bilateral adrenals rather than unilateral
      • Think about in the patient presenting in shock with TB risk factors
    • Arthritis
    • Osteomyelitis
      • Pott's disease, usually in thoracic spine

Differential Diagnosis

HIV associated conditions



  • Primary infection
    • Infiltrates in any area of the lung
    • Isolated hilar or mediastinal adenopathy may be only finding
  • Reactivation infection
    • cavitary/noncavitary lesions in upper lobe or superior segment of lower lobe
  • Latent infection
    • Upper lobe or hilar nodules and fibrotic lesions
    • Ghon foci, areas of scarring, calcification
  • Miliary TB
    • Looks like millet seeds on CXR
  • Immunocompromised patients less likely to have classic lesions and may have normal CXR

PCR Sputum Assay

  • Rapidly detects TB in sputum specimens (as well as rifampin resistance)
  • Use to rule-out patients for active TB
  • Need two sputum specimens (expectorated or induced) at least 8 hours apart (including at least one early morning specimen)


Active TB

Latent TB

  • Isoniazid x 9 months
  • Consider treatment for:
    • Recent conversion to PPD-positive
    • close contact with active TB
    • immunocompromised patients (or plan to start immunosuppressive medications)
  • New vaccine has demonstrated effectiveness (50%) in preventing progression to active TB[3]. However, this is not yet widely available and further research is needed.



  • Otherwise healthy
    • Contact public health services before discharge
      • Instructions for home isolation and follow up at appropriate clinic to receive meds
    • Do not start TB meds in ED unless specifically instructed by public health


  • Ill-appearing
  • Diagnosis is uncertain
  • Patient is treatment non-adherent


  1. Gutteridge, David L MD, MPH, Egan, Daniel J. MD. The HIV-Infected Adult Patient in The Emergency Department: The Changing Landscape of the Disease. Emergency Medicine Practice: An Evidence-Based Approach to Emergency Medicine. Vol 18, Num 2. Feb 2016.
  2. Sokolove PE, Derlet RW: Tuberculosis, in Walls RM, Hockberger RS, Gausche-Hill M, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 9. Philadelphia, Elsevier 2018, (Ch) 127:p 1682-1692.
  3. Final analysis of a trial of M72/AS01E vaccine to prevent tuberculosis Tait DR, Hatherill M, Van Der Meeren O, et al. N Engl J Med. 2019;381(25):2429-2439.
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