Definition

Disseminated tuberculosis (TB) is a contagious bacterial infection that has spread from the lungs to other organs of the body by the blood or lymph system.

See also: Tuberculosis - pulmonary

Alternative Names

Miliary tuberculosis; Tuberculosis - disseminated; Extrapulmonary tuberculosis

Causes, incidence, and risk factors

Infection can develop after inhaling droplets sprayed into the air from a cough or sneeze by someone infected with the Mycobacterium tuberculosis bacteria. Granulomas (granular tumors) develop in the infected tissue.

The usual site of the disease is the lungs, but other organs can be involved. In the U.S., most people with primary tuberculous lesions will heal and will have no further evidence of disease. Disseminated disease develops in the small number of infected people whose immune systems do not successfully heal the primary infection.

The disease can occur within weeks after the primary infection, or may lie dormant for years before causing illness. Infants, the elderly, and those infected with HIV are at higher risk for the disease worsening, because of their weaker immune systems.

In disseminated disease, organs and tissues affected can include:

• Bones and joints
• Bronchus
• Cervical lymph nodes
• Eye
• Larynx (voice box)
• Lining of the abdominal cavity (peritoneum)
• Lining of the brain and spinal cord (meninges)
• Lining of the heart (pericardium)
• Organs of the male or female urinary and reproductive systems
• Skin
• Small bowel
• Stomach

The risk of contracting TB increases among those who are in contact with people who have the disease, who live in crowded or unsanitary living conditions, and who have poor nutrition.

An increased incidence of TB has been seen recently in the U.S. Factors that may be causing this increase are tuberculosis infections in people with AIDS and HIV, and increasing numbers of homeless people.

Another matter of concern is the development of drug-resistant strains of TB. Incomplete treatment of TB infections (such as not taking medications for the prescribed length of time) can contribute to drug-resistant strains of bacteria.

About half of AIDS patients with a CD4 count less than 200 who develop TB will have disseminated disease (not localized disease, as in pulmonary tuberculosis).

Symptoms

The primary infection usually has no symptoms.

Symptoms of disseminated tuberculosis include:

• Cough
• Fatigue
• Fever
• General discomfort, uneasiness, or ill feeling (malaise)
• Shortness of breath
• Sweating
• Weight loss

Other symptoms that can occur with this disease:

• Abdominal swelling
• Chills
• Joint pain
• Paleness
• Swollen glands

Note: The symptoms will depend upon the affected body organ.

Signs and tests

A physical exam will reveal enlarged lymph nodes, enlarged liver, and enlarged spleen.

Tests:

• Biopsies and cultures of affected organs or tissues
• Bronchoscopy for biopsy or culture
• Chest x-ray
• Open lung biopsy
• Pleural biopsy
• Retinal lesions revealed with fundoscopy
• Sputum cultures
• Tuberculin skin test

This disease may also alter the results of the following tests:

• Mycobacterial culture of bone marrow
• Peripheral smear
• Serum calcium (may be elevated)

Treatment

The goal of treatment is to cure the infection with antitubercular drugs. These drugs include:

• Amikacin
• Ethambutol
• Ethionamide
• Isoniazid (INH)
• Para-aminosalicylic acid (PAS)
• Pyrazinamide
• Rifampin
• Streptomycin

Daily oral doses are continued for 1 year or longer.

For atypical tuberculosis infections, or drug-resistant strains, other drugs may be used to treat the infection. Treatment starts with a minimum of three drugs.

Hospitalization may be necessary to prevent spreading the disease to others until the infectious period is over, usually 2-4 weeks after the start of therapy. People can continue their normal activities after the infectious period.

Support Groups

Expectations (prognosis)

Most disseminated forms of TB respond well to treatment.

Complications

All medications used to treat TB can have side effects. Rifampin, pyrazinamide, and isoniazid may cause liver inflammation. Rifampin may also turn the tears and urine an orange or brown color, and can stain contact lenses and undergarments. Ethambutol may reduce vision or cause color blindness.

Other complications include:

• Adult respiratory distress syndrome (ARDS)
• Drug resistance
• Relapse of the disease
• Respiratory failure
• Tuberculous meningitis

Calling your health care provider

Call your health care provider if you know or suspect that you have been exposed to TB. All forms of TB need prompt treatment.

Prevention

Vaccination BCG is sometimes given to people who don't have tuberculosis, but who have been exposed to people with untreated TB. However, its effectiveness is under dispute. It is rarely used in the U.S. but is often used abroad, in countries with higher rates of tuberculosis.

Images

References

Golden MP. Extrapulmonary tuberculosis: an overview. Am Fam Physician. 2005;72:1761-1768.

Goldman L, Ausiello D. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007.

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