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Miliary Tuberculosis

General Considerations 

  • Widespread hematogenous dissemination of Mycobacterium Tuberculosis
  • So named because the nodules are the size of millet seeds (1-5mm with a mean of 2 mm)
  • Miliary TB represents only 1-3% of all cases of TB
  • Older men, African Americans and pregnant women are susceptible
  • Considered to be a manifestation of primary TB–although clinical appearance of miliary TB may not occur for many years after initial infection
  • When treated, clearing is frequently rapid
    • Miliary TB seldom, if ever, produces calcification
  • Under age 5, there is an increased risk of meningitis 

Risk Factors 

  • Immunosuppression
  • Cancer
  • Transplantation
  • HIV
  • Malnutrition
  • Diabetes
  • Silicosis
  • End-stage renal disease

Clinical Findings

  • Onset is insidious
  • Patients may not be acutely ill
  • Symptoms include
    • Fever and weight loss
    • Weakness and fatigue
    • Chills, night sweats are common
    • Cough
    • Hemoptysis
    • Anorexia
  • Hepatomegaly and lymphadenopathy are common

Imaging Findings

  • Takes weeks between the time of dissemination and the radiographic appearance of disease
  • Up to 30% have a normal chest radiograph
  • When first visible, they measure about 1 mm in size; they can grow to 2-3mm if left untreated
  • Produces innumerable, non-calcified nodules
  • High-resolution CT scans are more sensitive at demonstrating small nodules
  • Nodules are either sharply or poorly defined
  • 1–4-mm in size
  • Diffuse, random distribution
  • May be associated with intra- and interlobular septal thickening

Differential Diagnosis

  • Pneumoconiosis, especially silicosis or anthrosilicosis
  • Metastatic nodules, especially from thyroid carcinoma
  • Sarcoidosis


  • Estimated that up to 50% of cases are undiagnosed antemortem
  • Four-drug regimen to start
    • Isoniazid
    • Rifampin
    • Pyrazinamide
    • Ethambutol or streptomycin
  • Treatment may continue for 6-9 months
    • 9-12 months with meningeal involvement


  • Dissemination via bloodstream to
    • Lymph nodes
    • Liver
    • Spleen
    • Skeleton
    • Kidneys
    • Adrenals
    • Prostate
    • Seminal vesicles
    • Epididymis
    • Fallopian tubes
    • Endometrium
    • Meninges 


  • If not treated, almost 100% fatal
  • With treatment, less than 10% mortality

Miliary Tuberculosis

Miliary Tuberculosis

Miliary Tuberculosis. Top. Innumerable, small, millet-seed sized nodules are seen distributed throughout both lungs, shown in close up view below (white circle).
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Radiology. 1999;210:307-322. Pulmonary Tuberculosis: The Essentials  Ann N. Leung, MD