Miliary tuberculosis

Miliary Tuberculosis and Hematogenous Dissemination

Chest radiograph of miliary tuberculosis

Introduction

Miliary Tuberculosis (TB) is a form of tuberculosis characterized by a wide dissemination into the human body and the tiny size of the lesions (resembling millet seeds). It results from the hematogenous spread of Mycobacterium tuberculosis and represents a severe, often life-threatening form of TB.

Pathophysiology

Hematogenous Dissemination

Hematogenous dissemination occurs when Mycobacterium tuberculosis spreads through the bloodstream to various organs. This can happen in both primary infection and reactivation of latent TB.

Characteristics of Lesions

The lesions in miliary TB are small, typically 1-5 mm in diameter, and resemble millet seeds in appearance, hence the name 'miliary'.

Epidemiology

Miliary TB is more common in:

• Individuals with weakened immune systems, such as those with HIV/AIDS
• Young children and the elderly
• Patients with a history of TB or latent TB infection

Clinical Features

Patients with miliary TB may present with:

• Fever and night sweats
• Weight loss and fatigue
• Cough and difficulty breathing
• Organ-specific symptoms depending on the area of dissemination

Diagnosis

Methods of Diagnosis

• Chest X-ray: Shows a characteristic 'millet seed' pattern in the lungs
• Sputum Test: To identify Mycobacterium tuberculosis
• CT Scan or MRI: For more detailed imaging of affected organs
• Tuberculin Skin Test and IGRA (Interferon Gamma Release Assays): To detect TB infection

Treatment

Treatment involves a combination of antituberculosis drugs for an extended period, often lasting 6-12 months. The regimen typically includes:

• Isoniazid
• Rifampicin
• Pyrazinamide
• Ethambutol

Prevention

Preventive strategies include:

• Vaccination with the BCG vaccine in TB-endemic areas
• Early detection and treatment of latent TB infection
• Public health measures to reduce the transmission of TB

Complications and Prognosis

Untreated miliary TB can lead to serious complications, including:

• Disseminated organ failure
• Meningitis
• Death

The prognosis improves significantly with timely and adequate treatment.

Public Health and Global Impact

Miliary TB is a significant public health challenge, particularly in regions with high rates of TB and HIV co-infection.

External Links

• World Health Organization
• Centers for Disease Control and Prevention

See Also

• Tuberculosis
• Pulmonary Tuberculosis
• Latent Tuberculosis
• Antituberculosis Drugs

Miliary tuberculosis Resources
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