Tiêu đề 2. TUBERCULOSIS.pdf ✅

PHARMD GURU Page 1 DEFINITION: Tuberculosis (TB) is a communicable infectious disease caused by Mycobacterium tuberculosis. It can produce silent, latent infection as well as progressive, active disease. INTRODUCTION:  Tuberculosis (TB) is caused by organisms of the Mycobacterium tuberculosis complex, which includes M. tuberculosis, the most common and important agent of human mycobacterial disease, and M. bovis, which (like several other mycobacterial species) is acquired via ingestion of unpasteurized milk.  M. tuberculosis is a thin aerobic bacillus that is neutral on Gram’s staining but that, once stained, is acid-fast; i.e., it cannot be decolorized by acid alcohol because of the cell wall’s high content of mycolic acids and other lipids.  M. tuberculosis is transmitted from person to person by coughing or sneezing. Close contacts of TB patients are most likely to become infected.  Fifty-four percent of TB patients in the United States are foreign born, most often from Mexico, the Philippines, Vietnam, India, and China. In the United States, TB disproportionately affects ethnic minorities (African Americans, Hispanics, and Asians).  Human immunodeficiency virus (HIV) is the most important risk factor for active TB, especially among people 25 to 44 years of age. An HIVinfected individual with TB infection is over 100-fold more likely to develop active disease than an HIV-seronegative patient. EPIDEMIOLOGY:  Tuberculosis is most prevalent infectious disease in the world.  Tuberculosis is one of India's major public health problems.  According to WHO estimates, India has the world's largest tuberculosis epidemic and approximately two to three million people are infected with tuberculosis out of a global incidence of 8.7 million cases. This is a public health problem. India bears a disproportionately large burden of the world's tuberculosis rates, as it resides to be the biggest health problem in India. TUBERCULOSIS
PHARMD GURU Page 2 ETIOLOGY: Tuberculosis is caused by Mycobacterium tuberculosis, which spread from person to person through microscopic droplets released into the air. This can happen when someone with the untreated, active form of tuberculosis, coughs, speaks, sneezes, spits, laughs or sings. PATHOPHYSIOLOGY:
PHARMD GURU Page 3  Infection with TB requires inhalation of droplet nuclei.  Following deposition in the alveoli, Mycobacterium tuberculosis is engulfed by alveolar macrophages, but survives and multiplies within the macrophages. Proliferating bacilli kill macrophages and are released; this event produces a response from the immune system.  Exposure may lead to clearance of Mycobacterium tuberculosis, persistent latent infection, or progression to primary disease. Successful containment of TB is dependent on the cellular immune system, mediated primarily through T-helper cells (TH1 response). T cells and macrophages form a granuloma with a centre that contains necrotic material.  Mycobacterium tuberculosis, and peripheral granulation tissue consisting primarily of macrophages and lymphocytes; the granuloma serves to prevent further growth and spread of M.tuberculosis.  These individuals are non-infectious and have latent TB infection; the majority of these patients will have a normal chest X-ray (CXR) and be tuberculin skin test (TST) positive. Active TB typically occurs through a process of re-activation.  Approximately 10% of individuals with latent infection will progress to active disease over their lifetime. The risk is greatest within the two years following initial acquisition of M. tuberculosis.
PHARMD GURU Page 4  A number of conditions can alter this risk, particularly HIV infection, in which the annual risk of developing active TB is 8% to 10%. Immunocompromised conditions and treatment with immunosuppressing medicines, including systemic corticosteroids and TNF-α antagonists, also contribute to re-activation. CLINICAL MANIFESTATIONS: During initial infection and granulomas, there are no symptoms of mild bronchial pneumonia but sputum test is positive. In active TB, sign of chronic inflammation include:  Anorexia  Overall sensation of feeling unwell  Weight loss  Fatigue  Low grade fever  Night sweating  Coughing that lasts longer than 2 weeks with green, yellow, or bloody sputum  Shortness of breath  Chest pain  Hemoptysis. The occurrence of additional symptoms depends on where the disease has spread beyond the chest and lungs. For example, if TB spreads to the lymph nodes, it can cause swollen glands at the sides of the neck or under the arms. When TB spreads to the bones and joints, it can cause pain and swelling of the knee or hip. Genitourinary TB can cause pain in the flank with frequent urination, pain or discomfort during urination, and blood in the urine. RISK FACTORS: The person more prone to the infection includes:  Immigration and infection with HIV.  Frequent and prolonged contact.