Tuberculosis

Background

Miliary TB neonate born to mother with active TB

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

  Bilateral pulmonary tuberculosis

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 - milliary 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)
  

  Tuberculous lymphadenopathy
  

  Tuberculous vertebral osteomyelitis (Pott's Disease)
• 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, wt loss
• Extrapulmonary
  • Painless lymphadenopathy/scrofula (most common extrapulmonary manifestation)
  • Pericarditis
  • Peritonitis
  • Meningitis
  • Adrenal insufficiency
    • Think about in the patient presenting in shock with TB risk factors
  • Arthritis
  • Osteomyelitis
    • Pott's disease, usually in thoracic spione

Differential Diagnosis

HIV associated conditions

• HIV neurologic complications
  • Toxoplasmosis
  • Cryptococcosis
  • AIDS Dementia
  • Seizures in patients with HIV-AIDS
• HIV pulmonary complications
  • Pneumocystis jirovecii pneumonia (PCP)
  • Tuberculosis (TB)
• Ophthalmologic complications
  • CMV Retinitis
  • Herpes Zoster Ophthalmicus
• Other
  • AIDS fever of unknown origin
  • Immune reconstitution inflammatory syndrome
  • HIV diarrhea
  • Kaposi's sarcoma
  • Pruritic papular eruption of HIV
• HAART medication side effects
  • Lactic acidosis
  • Neuropyschiatric effects
  • Hepatic toxicity
  • Renal toxicity
  • Steven-Johnson's
  • Cytopenias
  • GI symptoms
  • Endocrine abnormalities

Evaluation

CXR

CXR of miliary TB

• 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)

Management

Active TB

• Isoniazid + rifampin + pyrazinamide + ethambutol x 8wk followed by INH/rifampin x18wk
  • 2 drug continuation treatment x 18-31wk

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 immunosupressive medications)

Disposition

Discharge

• 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

Admit

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

References

Authors

Ross Donaldson