Extrapulmonary Tuberculosis is a type of Tuberculosis that occurs outside of the lungs. It is called Extrapulmonary Tuberculosis (EPTB) because the most common organ of the body affected by Tuberculosis is the lungs. Tuberculosis is a multi-systemic disease (it affects many organs of the body) caused by Mycobacterium Tuberculosis (M. Tuberculosis). It may occur in isolation in different organs such as Bone and joints tuberculosis, abdominal tuberculosis, Breast TB or Skin tuberculosis; or it may be diffused – affecting different organs at the same time such as liver, spleen and kidney in this case, it is called disseminated tuberculosis or Miliary Tuberculosis.
Differences between Extrapulmonary Tuberculosis and Miliary Tuberculosis
- Extrapulmonary tuberculosis is any TB occurring outside the lungs while Miliary TB is a type of Extrapulmonary TB.
- Extrapulmonary tuberculosis may occur in a single organ of the body such as in the abdomen, skin, breast, bone or intestine whereas Miliary TB does not occur in isolation but is diffused or spread to different organs of the body
- Miliary TB is fatal without treatment whereas Extrapulmonary tuberculosis may just affect single organ such as the skin.
- Most cases of Extrapulmonary tuberculosis are post primary TB (occur after infection of pulmonary tuberculosis) whereas Miliary TB may occur during an active TB or post primary TB as it is caused by immunosuppresion.
Extrapulmonary tuberculosis Risk factors
- HIV infection
- Extremes of age
- Immunosuppression from other causes- Diabetes Mellitus, prolong steroid use and malignancies
Types of Extrapulmonary Tuberculosis (EPTB) Common sites affected in the body
- Tuberculosis of lymph nodes is called TB lymphadenitis this is the most common site of Extrapulmonary Tuberculosis in HIV negative individuals.
- Pleural TB is the most common site of Extrapulmonary Tuberculosis in HIV positive individuals
- Abdominal TB affects the Gastrointestinal tract and the peritoneum
- Pericardial TB affects the sac of the heart known as the pericardium.
- Central nervous system affects the brain tissue
- Bones and joints affects the bones such as in Potts disease (TB Spine)
- Genitourinary TB affecting the genital tract and urinary tract
- Uncommon extrapulmonary sites: other parts of the body can be affected but not common
- Miliary TB
Extrapulmonary Tuberculosis Pathogenesis
Extrapulmonary Tuberculosis usually occurs following a secondary spread from a pulmonary site.
Mode of Spread of Extrapulmonary Tuberculosis
- Contiguous spread to surrounding structures such as the pericardium of the heart and pleura of the lungs
- Lymphatic spread causes TB lymphadenitis
- Hematogenous spread occurs through the blood and may cause Miliary TB
- Occasionally EPTB may result from direct extrapulmonary infection of the Skin or GIT by consumption of unpasteurized milk
Extrapulmonary Tuberculosis Symptoms and Signs
- Low grade Fever
- Night sweats
- Evening chills
- Weight loss
These are the general symptoms of Tuberculosis that also occur in in Extrapulmonary TB. Symptoms may be atypical in patients with HIV or other immunosuppressive conditions such as Diabetes Mellitus. The other symptoms and signs are specific to the organ affected and are listed below.
TB Lymphadenitis Symptoms and signs
- Presents with lymph node enlargement that are usually > 4 cm in diameter
- The affected Lymph nodes are painless and freely mobile, but may become matted together
- The affected Lymph Nodes may undergo caseation necrosis and liquefaction, forming cold abscesses
- Abscess may drain unto the skin forming Scrofula
Pleural TB Symptoms and Signs
- This presents with features of pleural effusion (accumulation of fluid in the pleural space of the lungs)
- Worsening dyspnea (difficulty in breathing)
- Chest X ray features may include deviation of the trachea, stony dull percussion nodes, reduced or absent breath sounds in the affected side and homogenous opacity. Pleural effusion is usually unilateral (one sided)
Abdominal TB Symptoms and Signs
- Abdominal pain
- Rectal bleed may occur due to ulceration
- Ascites (abdominal swelling due to fluid accumulation in the peritoneum)
Pericardial TB Symptoms and Signs
- This typically presents with pleural effusion
- Ankle swelling
- Pleural rub
- Paradoxical pulse
- Distended neck veins
- Distant heart sounds
Most of the symptoms and signs of Pericardial TB are due to heart failure
Central Nervous System TB Symptoms and Signs
- TB meningitis: this presents with headache, neck stiffness and altered consciousness
- Tuberculoma: this presents with headache, focal body weakness and focal seizures
TB Meningitis and Tuberculoma are the two common presentations of Tuberculosis of the central nervous system.
Genitourinary TB Symptoms and Signs
- May present as Urinary tract infection (UTI) and patient will have flank pain, dysuria (difficulty in urinating) and increased urinary frequency
- There may be Scrotal mass in males
- Pelvic inflammatory disease in females
Uncommon extrapulmonary sites and their symptoms and signs
- TB Skin will have skin nodules
- TB Breast will have unilateral breast enlargement
- Upper respiratory tract when affected, the Larynx will present with Hoarse voice, cough and odynophagia (painful swallowing)
- Otitis media (when it affects the ear) it presents with hearing impairment
Extrapulmonary Tuberculosis Diagnosis and Investigations
- Fine needle aspiration and lymph node biopsy in TB lymphadenitis
- Culture of biopsy specimen of the affected organ
- Abdominal Ultrasound in Abdominal TB may show intra-abdominal lymph node enlargement, organ enlargement and ascites
- Chest radiology may show cardiomegaly in Pericardial TB
- Electrocardiography (ECG) may show low voltages in all the leads in Pericardial TB
- Echocardiography will demonstrate pericardial fluid and thickened pericardium in Pericardial TB
- Cerebral CT scan will show tuberculomas in CNS TB
Investigations for Extrapulmonary Tuberculosis are done based on the organ affected.
Extrapulmonary Tuberculosis Treatment
- Treatment of Extrapulmonary Tuberculosis is based on standard TB treatment using Rifampicin, Isoniazid, Pyrazinamide, Ethambutol with or without Streptomycin and Steroids (depending on the type of TB and organ affected)
- Underwater chest tube drainage for large pleural effusions in Pleural TB
- Surgery may be indicated in abdominal TB in cases of massive gastrointestinal bleeding, intestinal obstruction and bowel perforation
- Pericardiocentesis is done when there is Cardiac tamponade in Pericardial TB
- Pericardial stripping is required in constrictive pericarditis caused by Pericardial TB
Extrapulmonary Tuberculosis can spread to many organs of the body, however, it can be treated.