Disseminated tuberculosis
Definition
Disseminated tuberculosis (TB) is a contagious bacterial infection that has spread from the lungs to other parts of the body through the blood or lymph system.
See also: Tuberculosis - pulmonary
Alternative Names
Miliary tuberculosis; Tuberculosis - disseminated; Extrapulmonary tuberculosisCauses
Tuberculosis infection can develop after inhaling droplets sprayed into the air from a cough or sneeze by someone infected with the Mycobacterium tuberculosis bacteria. Small areas of infection, called granulomas (granular tumors), develop in the lungs.
The usual site of tuberculosis is the lungs, but other organs can be involved. In the U.S., most people with primary tuberculous get better and have no further evidence of disease. Disseminated disease develops in the small number of infected people whose immune systems do not successfully contain the primary infection.
Disseminated 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 catching TB increases when you are in contact with people who have the disease, if you live in crowded or unsanitary conditions, and if you have poor nutrition.
Recently, TB has been seen more often 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 the development of 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 lung 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
- Pale skin due to anemia (pallor)
- Swollen glands
Note: The symptoms will depend upon the affected areas of the body.
Exams and Tests
A physical exam may show:
Tests for tuberculosis include:
- Biopsies and cultures of affected organs or tissues
- Bronchoscopy for biopsy or culture
- Chest x-ray
- Fundoscopy may reveal retinal lesions
- Open lung biopsy
- Pleural biopsy
- 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)
- Moxifloxacin
- Para-aminosalicylic acid (PAS)
- Streptomycin
Daily oral doses are continued for 1 year or longer. Directly observed therapy, in which a health care provider watches the patient take the prescribed antitubercular drugs, is the most effective strategy for some patients. In this case, drugs may be given 2 or 3 times per week, as prescribed by a doctor.
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.
Outlook (Prognosis)
Most disseminated forms of TB respond well to treatment.
Possible 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
When to Contact a Medical Professional
Call your health care provider if you know or suspect that you have been exposed to TB. All forms of TB need prompt evaluation and treatment.
Prevention
The vaccine BCG is sometimes given to people who don't have tuberculosis, but who have been or may be exposed to people with untreated TB. Its effectiveness is unclear. It is rarely used in the United States but is often used abroad, in countries with higher rates of tuberculosis.
References
Iseman DE. Tuberculosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 345.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
