TUBERCULOSIS


Pulmonary tuberculosis (TB) is a contagious bacterial infection that involves the lungs, but may spread to other organs. India has highest incidence in world.

Causes, incidence, and risk factors

Pulmonary tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis (M. tuberculosis). You can get TB by breathing in air droplets from a cough or sneeze of an infected person. This is called primary TB.

Most people will recover from primary TB infection without further evidence of the disease. The infection may stay inactive (dormant) for years. However, in some people it can reactivate.
Most people who develop symptoms of a TB infection first became infected in the past. However, in some cases, the disease may become active within weeks after the primary infection.
The following people are at higher risk for active TB: Elderly, Infants, People with weakened immune systems, for example due to AIDS, chemotherapy, diabetes, or on certain medications

Your risk of contracting TB increases if you:
• Are in frequent contact with people who have TB
• Have poor nutrition
• Live in crowded or unsanitary living conditions
• The following factors may increase the rate of TB infection in a population:
• Increase in HIV infections
• The appearance of drug-resistant strains of TB has become common now.


 
 
   

Symptoms

The primary stage of TB usually doesn't cause symptoms. When symptoms of pulmonary TB occur, they may include:
• Cough (usually cough up mucus)
• Coughing up blood
• Excessive sweating, especially at night
• Fatigue
• Fever or feverishness
• Unintentional weight loss

Signs and tests

Clubbing of the fingers or toes (in people with advanced disease) Swollen or tender lymph nodes in the neck or other areas Fluid around a lung (pleural effusion) Unusual breath sounds (crackles)
Tests may include:
CBC and Corrected ESR
Chest x-ray
Tuberculin skin test (also called a PPD test)
Sputum examination and cultures
Biopsy of the affected tissue (rare)
Bronchoscopy
Chest CT scan
Interferon-gamma blood test such as the QFT-Gold test to test for TB infection
Thoracentesis

Treatment

The goal of treatment is to cure the infection with drugs that fight the TB bacteria. Treatment of active pulmonary TB will always involve a combination of many drugs (usually four drugs). The therapy last minimum of 6 or 9 months for full treatment. Patient is followed every month with CXR etc to have final eradication.

The most commonly used drugs include:
Isoniazid
Rifampin
Pyrazinamide
Ethambutol
Other drugs that may be used to treat TB include:
Amikacin/
Ethionamide /Proethionamide
Cycloserine
Moxifloxacin / Ciprafloxacillin / Levofloxcillin
Para-amino salicylic acid
Streptomycin
When people do not take their TB medications as recommended, the infection may become much more difficult to treat. The TB bacteria may become resistant to treatment, and sometimes, the drugs no longer help treat the infection (MDR)

Expectations (prognosis)

Symptoms often improve in 2 - 3 weeks. A chest x-ray will not show this improvement until weeks or months later. The outlook is excellent if pulmonary TB is diagnosed early and treatment is begun quickly. Treatment last for 6-9 months. Initial treatment of 2-3 months is called Intensive phase and later 4-6months therapy is called maintenance treatment.

Complications

Pulmonary TB can cause permanent lung damage if not treated early. Medicines used to treat TB may cause side effects, including liver problems. Other side effects include:
Changes in vision
Orange- or brown-colour tears and urine
Rash