Tuberculosis: Causes, Symptoms and Diagnosis

tuberculosis disease

Tuberculosis: the second biggest killer globally is infection of the lungs which if not treated in time can spread to other organs of the body as well. Tuberculosis is more commonly known as TB in common language. Tuberculosis causing bacteria can easily spread from one person to another through the tiny droplets released through cough and sneezes of the infected person.

Types of Tuberculosis

Tuberculosis can be divided into two heads as per the infective stage of the disease. The two types of tuberculosis are:

Latent Tuberculosis– In latent tuberculosis; the disease causing bacteria is present in an inactive state in the body. Latent tuberculosis shows no presence of any clinical symptoms which makes it really difficult to diagnose TB at this stage. Latent tuberculosis can lead to active Tuberculosis.

Active Tuberculosis- Active stage is the infective stage where the bacteria are active and symptoms are visibly present. Patients are highly infective and pose a risk to other individuals.

Tuberculosis: Causes

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis. Lungs are the primary organs affected by Tuberculosis. The tuberculosis bacilli are carried in droplets and are spread from the infected person to healthy individuals through air. The size of these particles is around 5 to 10 microns and they travel through the alveolar spaces to establish infection in the lungs.

The bacilli proliferate inside alveolar macrophages (natural defence cells of the body). The infected macrophages secrete chemicals which attract other defence cells which form a structure called the tubercle. If the infection is uncontrolled, the tubercle enlarges and the bacteria enter the lymphatic system. Thus the infection spreads. Tuberculosis has re emerged as a major health concern which has a high mortality rate.

tuberculosis causesTuberculosis: Symptoms

Tuberculosis causes a variety of clinical symptoms. It mainly affects the lungs but it can also spread to other parts of the body. The major symptoms include:

Persistent cough or presence of blood in cough

  • Fever and malaise
  • Loss of appetite
  • Fatigue
  • Unintentional weight loss and tiredness
  • Swollen lymph nodes
  • Shortness of breath
  • Pain in the chest
  • Phlegm
  • Night sweats or sweating

These are the general symptoms of pulmonary Tuberculosis. Without proper treatment in time the infection can spread to other parts of the body through the bloodstream.

It can cause pain and bone destruction as well and leads to meningitis in the brain. It also affects the liver and the kidneys and causes impairment. It also affects the heart and causes cardiac tamponade which is a fatal condition. When there is massive spread of the tuberculosis bacilli the condition is called military tuberculosis. Military tuberculosis is condition which represents a severe form of Tuberculosis which affects other organs as well. Tuberculosis is a fatal disease which causes a huge number of deaths worldwide. It primarily affects the heart, brain and the spinal cord.

Tuberculosis is a major public health concern worldwide. Tuberculosis mostly occurs in developing countries. Poverty, HIV and multidrug resistance are some of the major culprits that empower tuberculosis into an epidemic. Poor living conditions are another major risk factor. People with a weak immune system, including young children, are at a higher risk. Also people with chronic diseases or compromised immune system are more prone to TB.

High risk groups for Tuberculosis include:

  • Family members and people living close to the infected person
  • People immigrating to or from areas with high prevalence of Tuberculosis
  • Children as their immune system is still developing which puts them at higher risk
  • Groups with high rates of Tuberculosis transmission such as drug addicts, homeless individuals and people with HIV
  • Heath care individuals who work or reside with TB patients in health care facilities
  • People living in crowded and unhygienic environment

People with compromised immune system due to pre-existing disease.The diseases which affect the immune system and increase the chance of contracting TB are;

  • HIV infection
  • Drug abuse
  • Diabetes mellitus
  • Severe kidney diseases
  • Cancer
  • Organ transplants

tuberculosis diagnosisDiagnosis of Tuberculosis

It is really important to diagnose tuberculosis in time to provide the required treatment. Several factors like presence of chronic cough, fever need to be diagnosed immediately. There are various tests for Tuberculosis are listed below:

  1. Culture test- A sample of tissue or body fluid is taken from the patient. Usually sputum sample is collected and the culture tests are done under laboratory conditions. A positive sample shows bacterial growth.
  2. Chest X-ray- It is used as a preliminary test. If damage is spotted, further tests are advised
  3. Sputum smear microscopy- Sputum sample is collected and observed under a microscope. Visible TB bacteria are indicative of an active TB infection in the lungs and throat. This indicates pulmonary TB.
  4. Gen expert system identifies bacteria from sputum samples. This test is more sensitive than the culture test.
  5. TB Skin test- Mantoux test checks the immune response to TB bacteria.Tuberculin is injected in the skin of the elbow. If a hard bump or swelling develops on the arm,it indicates the presence of TB infection.
  6. Serological tests- Blood is withdrawn and the test is performed in a single visit. The infection is detected on the basis of the presence of antibodies in the blood.
  7. Interferon gamma release essay-it is a new test which is becoming widely available. It is performed in case of positive Mantoux test.

A complete medical evaluation which includes physical examination, medical history and diagnostic tests including chest x-ray, sputum tests and the other investigations recommended by the doctor is used for the proper diagnosis of an active infection of tuberculosis.