An infection caused by Mycobacterium tuberculosis.
There are 2 billion people worldwide who are infected with tuberculosis (TB).
The initial infection usually leads to a latent (later, sleeping) asymptomatic infection.
The causes for asymptomatic infection is caused by reactivation of the latent infection of the Mycobacterium.
The most common infection is the pulmonary infection, but there is another type of infections such as the disseminated infection and the extrapulmonary infection (the infected area is outside of the lung).
The tuberculosis bacterium can infect almost all organ systems in the human body except the bloodstream. It can also infect the central nervous system, genitourinary system, Os (bones) and gastrointestinal tract.
There are certain risk factors for reactivating the latent infection which occurs through;
Immunosuppression through contracting the disease HIV and AIDS.
Alcoholism.
Preexisting lung disease.
Diabetes.
Advancing age.
The risk factors for contracting tuberculosis in America are;
Homelessness and crowded living conditions such as prisons.
Through travelling from third world countries and by being employed in a health profession.
Direct interaction with tuberculosis patients.
The stereotypical symptoms and patient history for tuberculosis would be;
Coughing.
Hemoptysis.
Dyspnea.
Weightloss.
Fatigue.
Night Sweats.
Fever.
Cachexia.
Hypoxia.
Tachycardia.
Lymphadenopathy.
Abnormal lung exam.
Patient having symptoms for longer than three weeks.
For HIV patients, it is familiar with atypical signs and symptoms such as extrapulmonary tuberculosis.
How do I diagnose a patient as a doctor?
There are multiple ways to diagnose a patient, and some test is faster than others, such as sputum acid-fast stain test; however, the test lacks sensitivity.
Other tests may be a sputum culture test, blood test and a tissue test which these two are the most thorough test to establish the diagnosis.
The other way to diagnose is to do an X-ray exam, where you as a doctor would find a cavitary infiltrate in the upper lobe which also could be accompanied with calcification of or more nearby lymph node and this finding is also called Ghon Complex.
When it comes to HIV patients, it is common that their X-ray exam shows lower infiltrates with or without calcification.
If you find on the X-ray exam multiple fine nodular densities throughout both lungs, then it shows military tuberculosis which represents hematologic or lymphatic dissemination.
What is essential to know is that the interpretation and management of the Mantoux tuberculin skin test are the same for patients who have not been administered the BCG vaccine.
Although they should be tested with Quantiferon-TB instead.
The typical findings while viewing a sample through the microscope for the Mycobacterium is the colour of the Mycobacterium, which shows red colours in the form of “red snapper” of tubercle bacilli.
What does the doctor need to know about the PPD test?
First, Alcohol should be applied to the forearm. Secondly, the PDD should be injected intradermally on the volar surface of the forearm. The diameter of induration is measured at 48-72 hours.
The BCG vaccination typically renders a patient PPD positively but should not preclude prophylaxis as recommended for unvaccinated individuals. The size of induration that indicates a positive test is interpreted follows;
If the patient has an induration (hardening of the skin) over 5 millimetres, it is positive in HIV infected patients.
If the patient has an induration over 10 millimetres, it is considered positive for IV drug use patients, residents of third world countries, chronic illness, residents of health and correctional institutions and healthcare workers.
More than 15 millimetres it shows; Everyone else, including those without known risks factors.A negative reaction with negative control implies clonal anergy from immunosuppression, old age, or malnutrition and thus does not rule out tuberculosis.
All patients with latent, asymptomatic type should be skin diagnosed with a positive tuberculin test (TST) or QuantiFERON -TB.
For those with immunocompromised individuals with latent TB infection may have a negative TST (anergy).
What is the recommended treatment for patients with tuberculosis?
All cases, both the latent type and the active type must be reported to local and state health departments.
The patient should be ordered into respiratory isolation if active tuberculosis is suspected.
Treatment for active tuberculosis should be as follows;
Directly observed multidrug therapy with a four-drug regimen such as Isoniazid, pyrazinamide, rifampin, ethambutol which should be taken by the patient for two months. Followed by Isoniazid and rifampin for four months.
Administer vitamin B6 (pyridoxine) with Isoniazid to prevent peripheral neuropathy.
If the patient has the latent type of tuberculosis and shows no signs or symptoms of disease then administer isoniazid for nine months and as well there is an alternative option for these type of patients which include taking isoniazid for six months instead of taking rifampin for four months.About the choice of treatment
Rifampin turns the body fluids orange which is also including the tears.
Ethambutol can cause optic neuritis
Isoniazid may cause peripheral neuropathy and drug-induced hepatitis.
The Mnemonic for remembering the 4 drugs to administer to the patients is the word RIPE.
Rifampin
Isoniazid
Pyrazinamide
Ethambutol.
