TB and treatment Flashcards
What is TB, the most common form and its symptoms?
a disease caused by infection with bacteria of the TB complex, most common form is pulmonary TB and symptoms include persistent productive cough (blood)
What are the 3 outcomes post infection?
elimination, latent infection or progression to active TB
How are respiratory and non-respiratory TB diagnosed?
Respiratory: chest x ray and at least 3 sputum samples. Non-respiratory: needle aspiration or biopsy from any site of suspected TB
Describe the pathogenesis of TB
droplet nuclei containing tubercle bacilli is inhaled and travels to alveoli, tubercle bacilli multiplies in alveoli where infection begins, small number enter blood stream and spread throughout body, within 2-8 weeks, immune system produces macrophages that surround bacilli, forming a barrier shell which keeps bacilli contained and under control (latent infection). If immune system can’t keep tubercle bacilli under control, starts to multiply rapidly and cause disease
What are the types of drug resistance?
mono-resistant, poly-resistant (at least 2 but not isoniazid and rifampin), multi drug resistant (resistant to at least rifampin and isoniazid), extensively drug resistant (isoniazid and rifampicin + any fluoroquinolone + at least 1 of 3 injectable 2nd line drugs)
How is TB treated?
4+ drugs for simplest regimen, 6-9 months of treatment, isolation until non infectious
What is the role of public health workers in the management of TB?
They must: educate and coordinate care, identify support services. Treat TB geriatric populations, treat TB in children, deal with alcohol, drug abuse, incarcerated/homeless patients, provide culturally appropriate care for non-english speaking/ non literate populations and drug resistance
What strain does the BCG vaccine contain and how is it administered?
contains live attenuated strain of M bovis, administered intra dermally, single dose
Which groups of people are given the vaccine?
all infants in area of high incidence, all infants with parents born in high incidence country and travellers/emigrants
What is the purpose of the Mantoux test?
used to screen for infection or disease prior to immunisation, if a local skin reaction is caused when tuberculin purified protein derivative is injected the patient is either infected or has active disease
In vaccine development, what are the 2 main strategies being pursued?
A pre-infection vaccine and a post-exposure vaccine
Describe the structure of mycobacteria
thick waxy impermeable cell wall (so difficult to stain), cell wall rich in mycolic acids which are long chained fatty acids, very hydrophobic, very slow growing bacteria which caused TB, leprosy and Buruli ulcer
What drugs are used to treat drug sensitive TB?
Isoniazid, Rifampicin, Ethambutol and Pyrazinamide (HREZ)
What drugs should be used to treat MDR TB?
Streptomycin, Isoniazid, Rifampicin, Ethambutol and Pyrazinamide (SHREZ)
What drugs should be used to treat XDR TB?
SHREZ but add fluoroquinolone, cycloserine and possibly other drugs
