6 July 2020
What is Tuberculosis?
Tuberculosis or TB is a bacterial infection, which commonly affects the lungs (Pulmonary Tuberculosis). Although the bacteria can spread through the blood stream and affect other organs in the human body (Extrapulmonary Tuberculosis).
What is the cause of tuberculosis?
As already said tuberculosis is a bacterial infection, the bacterium named Mycobacterium Tuberculosis is the cause of this disease.
How the bacteria get transmitted?
Tuberculosis is transmitted from one person to another through airborne droplets from the infected individual when they cough, sneeze or spit.
What are the symptoms of tuberculosis?
A productive cough for more than 3 weeks duration.
Patients typically presents with weight loss
Loss of appetite
Difficulty in breathing and chest pain
Coughing up bloody mucous.
What is the diagnostic test for tuberculosis?
Mantoux tuberculin skin test
AFB smear and culture test
Interferon-gamma release assays (IGRAs).
What are the types of tuberculosis?
They are 2 types of tuberculosis:
Latent tuberculosis: People with Latent Tuberculosis infection have bacteria causing tuberculosis in their body, but not enough to cause sickness or spread the bacteria to other individuals. But people with latent tuberculosis need to be treated with antibiotics in order to reduce the risk of progression to active tuberculosis.
Active tuberculosis: People with Active Tuberculosis infection have bacteria causing tuberculosis which is active and multiply in the body and makes the individuals sick. Individuals with active TB can spread the bacteria to others.
What is Drug- resistant tuberculosis?
Drug-resistant tuberculosis is caused by Mycobacterium tuberculosis organisms that are resistant to the drugs normally used to treat the disease. They are of two types:
Multidrug - resistant tuberculosis (MDR-TB): It is a type of drug- resistant tuberculosis where the bacteria causing tuberculosis is resistant to treatment with at least two of the most effective first-line anti-tuberculosis drugs (i.e., Isoniazid and Rifampin).
Extensively drug-resistant tuberculosis (XDR-TB): It is a rare type of drug-resistant tuberculosis. In this type the bacteria causing tuberculosis is resistant to isoniazid, rifampin, any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, capreomycin). This type of drug resistant tuberculosis is resistant to both first-line and second-line drugs.
How tuberculosis is treated?
Tuberculosis is treated with antibiotics. Drug treatment is continued for atleast 6 months and up to 2 to 3 years for some cases of multidrug-resistant tuberculosis.
a) Treatment for Latent Tuberculosis:
There are 3 treatment options:
I. Isoniazid: It is the preferred treatment for latent TB which is generally given for 9 Months.
II. Rifampin: It can be used when Isoniazid resistance is suspected or when the patient cannot tolerate Isoniazid. It is given for 4 Months.
III. Isoniazid/ Rifapentine: It is given for a period of 12 week. This regimen is an equal alternative to 9 months of daily isoniazid for treating latent tuberculosis infection.
b) Treatment for Active Tuberculosis:
The antibiotics used for the treatment of active tuberculosis are:
The standard active Tuberculosis treatment regimen is Isoniazid, Rifampin, Pyrazinamide and Ethambutol for 2 months, followed by isoniazid and rifampin for 4 months.
c) Treatment for Multidrug - Resistant Tuberculosis (MDR-TB):
If the bacteria is resistant to drug, the aim is to introduce two or more active medications that the patient has not received previously. For MDR-TB, no standard regimen can be proposed.
If the organism causing TB does not respond to the effective first- line agents (i.e. Isoniazid, Rifampin, Pyrazinamide, Ethambutol) then the patient will be treated with a combination of second-line drugs for a longer period (i.e. 2-3 Years).
The second-line agents are:
Para-Amino salicylic acid (PAS)
The drug resistance can be suspected in the following situations:
· Patients who fail therapy or relapse after treatment
· Patients known to be exposed to MDR- TB cases
· Patients who still have positive cultures after 2 to 4 months of therapy
· Patients who still have acid fast bacilli- positive sputum smear after 2 months of therapy.
· Patients who have received prior therapy for tuberculosis.
Can tuberculosis be cured?
Yes, Tuberculosis is curable. But remember tuberculosis can be fatal. Therefore, finishing treatment and adherence to the prescribed regimen is the only way to cure tuberculosis completely.
Whether monitoring is needed for the patients under tuberculosis treatment?
Yes, Monitoring and evaluation of therapeutic outcome is highly needed for the patients taking Anti-tuberculosis drugs.
Nonadherence to the prescribed regimen is the most serious problem with Tuberculosis therapy. Direct Observed Therapy is the most effective way to ensure adherence.
AFB smear positive patients should have sputum samples sent for AFB stains every 1-2 weeks until two consecutive smears are negative.
Patients should have sputum cultures performed monthly until negative, which generally occurs over 2-3 months.
Drug susceptibility testing and serum drug concentrations should be checked if sputum cultures continue to be positive after 2 months.
Blood urea nitrogen (BUN), Serum Creatinine, Aspartate transaminase, Alanine transaminase and Complete Blood Count should be taken at baseline and periodically. Hepatotoxicity should be suspected, if transaminases exceed five times the upper limit of normal and total bilirubin exceeds 3mg/dL. At this state, the offending agents should be discontinued and appropriate alternative should be selected.
How to prevent the spread of tuberculosis?
Patients with active tuberculosis can infect other persons. In order to prevent, you should follow the below mentioned points:
Active TB patient should stay home during the first few weeks of treatment and until you are no longer contagious.
Avoid having contact with peoples with weakened immune systems (i.e. peoples like elderly, children and patients with HIV).
Avoid visiting the public places. Wear face mask while stepping out in case of any emergency.
Active tuberculosis patients may be hospitalized until the bacteria are no longer expelled in their cough and the patient is no longer contagious.