Disseminated tuberculosis is a type of tuberculosis (TB) where mycobacteria spread via blood to other organs beyond the lungs. It can cause severe multiple-organ damage in the absence of early treatment.

Mycobacterium tuberculosis (M. tuberculosis) — the bacteria that cause TB — has the potential to invade the blood and lymphatic system, causing disseminated disease.

In some people with a weakened immune system or other contributing factors, M. tuberculosis can spread to the liver, bone marrow, eyes, and kidneys, among others. Symptoms may vary but can include prolonged fever, weight loss, and fatigue.

Diagnosing disseminated TB can be challenging and usually requires clinical evaluation, lab tests, and imaging. Treatment usually involves a combination of anti-tuberculosis medications for 6–9 months.

This article discusses disseminated tuberculosis, its causes, symptoms, and available treatment options.

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Mycobacterium tuberculosis (M. tuberculosis) is usually responsible for causing TB. It can be transferred from person to person via droplets in the air. When a person inhales infectious droplets, the bacteria may attach to the lungs and cause infection. This is known as pulmonary TB.

However, when M. tuberculosis enters the blood or lymphatic system, it has the potential to spread throughout the body. When TB affects two or more noncontiguous — or non-neighboring — sites, it is known as disseminated TB.

Some body parts disseminated disease can affect include:

Certain factors can increase the risk of disseminated tuberculosis, including:

  • HIV infection: People who have untreated HIV and a low CD4 count are typically at greater risk of developing disseminated TB, usually with abdominal involvement.
  • Advancing age: Older people are more vulnerable to disseminated TB, usually bone TB, in people older than 45 years old.
  • Chronic medical diseases: Long-term medical disorders like liver disease can increase a person chance of developing the condition.
  • Environmental factors: People living in areas with a high TB prevalence or living in overcrowded places are more likely to develop the condition.
  • Certain medications: Some medications — like immunosuppressants — can affect the body’s immune system and how a person responds to disease-causing agents like M. tuberculosis.
  • Having food insecurity, which can include limited access to high nutrient foods: The World Health Organization (WHO) classes this to be an important risk factor for developing active TB disease.

The location of the disease and how far it has spread from the original location can determine the symptoms a person experiences. Therefore, disseminated tuberculosis symptoms vary for each person, but here are some possible ones:

  • abdominal pain or swelling
  • distressing cough
  • shortness of breath
  • fatigue
  • fever
  • ill feeling or malaise
  • joint pain
  • pale skin
  • sweating
  • swollen lymph nodes
  • unexplained weight loss

Individuals who suspect they may have symptoms of disseminated tuberculosis will benefit from immediate medical attention and therapy.

Disseminated TB diagnosis requires a combination of clinical evaluation and diagnostic tests.

Clinical evaluation typically involves taking a medical history, and doctors may perform a physical examination. It may reveal swelling of lymph nodes or other affected organs.

There are various diagnostic tests available for diagnosing disseminated tuberculosis. Multiple tests may be necessary.

The Centers for Disease Control and Prevention (CDC) recommends the following:

  • Tuberculin skin test: It helps to identify individuals exposed to tuberculosis. But it is not a confirmatory test.
  • Blood tests: Also known as interferon-gamma release assays (IGRAs). These tests identify people with an infection, and a positive test usually requires further testing for confirmation purposes. Examples include:
    • QuantiFERON®-TB Gold Plus (QFT-Plus)
    • T-SPOT® TB test (T-Spot)
  • Smear and culture of sputum samples: Specifically, these tests look to detect acid-fast bacilli (AFB) — of which M. tuberculosis is one — under the microscope. In people where a sputum sample cannot be obtained, bronchoscopy is necessary to obtain a tissue sample.
  • Radiological tests: Imaging tests such as X-rays or computed tomography (CT) scans of the affected region or organ can also support a diagnosis.
  • Molecular testing: Polymerase chain reaction (PCR) tests can detect TB nucleic acids and aid in rapid diagnosis.
  • Drug susceptibility tests: This is mainly to determine how a person will likely respond to treatment and which drug would be unsuitable to use.

Treatment typically involves combining multiple anti-tuberculosis medications. This involves a combination of the following:

  • isoniazid
  • rifampicin
  • pyrazinamide
  • ethambutol

These medications are the first-line treatment choice for disseminated tuberculosis treatment in the absence of a drug resistance health history.

The guidelines for disseminated tuberculosis therapy include the following:

  • initially, 2 months of isoniazid, rifampin, pyrazinamide, and ethambutol.
  • 4–7 months of isoniazid and rifampin subsequently.

The total treatment duration is 6–9 months, but this may be longer in some TB diagnoses. Individuals may benefit from close monitoring for adverse effects and long-term responses to therapy.

People who have received the following confirmed diagnoses typically benefit the most from early diagnosis and treatment:

  • those with suspicious tuberculosis symptoms that are worsening gradually over time
  • those with a history of pulmonary tuberculosis
  • those with other medical conditions, such as HIV or liver disease

Anyone who suspects they have TB or has recently had contact with a TB-positive person can typically benefit from seeking medical help, which can help doctors provide an early diagnosis.

The outlook for disseminated tuberculosis depends on various factors, including:

  • a person’s health status
  • the specific strain of M. tuberculosis causing infection
  • how early treatment starts

Early diagnosis and immediate treatment — coupled with adherence to the prescribed treatment regimen — can generally have a positive effect on outlook.

When treatment is delayed, disseminated tuberculosis has the potential to cause extensive multisystemic organ dysfunction.

The following are some of the complications:

Preventing tuberculosis infection is one way to reduce the risk of developing disseminated tuberculosis. The following recommendations can help prevent tuberculosis infection:

  • administration of the Bacillus Calmette-Guérin (BCG) vaccine
  • isolation of individuals with active TB
  • strengthening the immune system by engaging in health-promoting lifestyle choices, such as eating high nutrient foods, staying physically active, and reducing stress

Learn more about preventing TB.

Below are some commonly asked questions about disseminated TB:

What is the difference between disseminated TB and pulmonary TB?

Pulmonary TB is a type of tuberculosis that affects only the lungs. In contrast, disseminated tuberculosis occurs when the bacteria causing tuberculosis spread beyond the lungs to other areas of the body.

Can you catch disseminated TB?

Disseminated tuberculosis is contagious, so it is possible to contract the bacteria that causes it when a person comes into contact with someone with TB. Individuals with compromised immunity are more vulnerable to contracting the disease-causing agent.

What is the difference between military and disseminated TB?

Miliary TB is a severe form of disseminated tuberculosis in which the bacteria spread beyond the lungs to other areas. Miliary TB has a characteristic millet-seed-like appearance on a chest X-ray, unlike disseminated TB.

Disseminated tuberculosis is a type of tuberculosis in which the disease-causing organism — usually M. tuberculosis — spreads to other organs beyond the lungs. It is contagious and is typically more likely to affect someone with weakened immunity, such as someone with HIV.

The symptoms vary depending on the organ affected, and treatment typically involves at least 6–9 months of a combination of different anti-tuberculosis medications. Early and prompt treatment is critical for reducing the risk of complications and increasing the likelihood of a positive outlook in people with the condition.