chapter 46 key terms

Term Definition
aerobic requiring oxygen for the maintenance of life
anti tubercular drugs drugs used to treat infections cause by Mycobacterium bacterial species
bacillus a rod shaped bacterium
granulomas small nodular aggregations of inflammatory cells (macrophages, lymphocytes) has delimited boundaries
interferon gamma release assays (IGRA's) surrogate markers of mycobacterium tuberculosis infection. indicate a cellular immune response to M tuberculosis
Isoniazid primary and most commonly prescribed anti tubercular drug
multidrug resistant tuberculoses (MDR-TB) tuberculosis that demonstrates resistance to two or more drugs
slow acetylator an individual with genetic defect that cases a deficiency in the enzyme needed to metabolize isoniazid the most widely used tubuerculosis drug
tubercle bacillus the characteristic lesion of tuberculosis a small round grey translucent granulomatous lesion. usually with caseated (cheesy) consistency in its interio
tubercle bacilli another common name for rod shaped tuberculosis bacteria; essentially synonymous with mycobacterium tuberculosis
tuberculosis (TB) any infectious disease caused by species of mycobacterium usually mycobacterium tuberculosis
TB is commonly characterized by granulomas in the lungs- nodular inflammatory cells that are walled of with clear boundaries and have a centre that is cheesy or caseated
MTB (mycobacterium tuberculoses) is an aerobic bacillus- a long and slender, rod shaped microorganism
MTB has a need for highly oxygenated blood – explains why it most commonly effects the lungs
early manifestation of MTB nonspecific and include a productive cough that lasts longer than 2 weeks and may contain blood, weight loss, chest pain, weakness, fatigue, loss of apetite
other common infection sites of MTB growing ends of bones and the brain (cerebral cortex)
tubercle bacilli (synonym for MTB) transmitted from humans, cows, or birds.
tubercle bacilli are conveyed in droplets expelled by infected people or animals during coughing or sneezing and are then inhaled by the new host
MTB is a slow growing organisms -makes it more difficult to treat
many antibiotics used to treat TB work by inhibiting growth
slow growing microorganisms are harder to kill because their cells are not as metabolically active as those of faster growing microorganisms
first infectious episode is considered the primary TB infection
patents with dormant bacteria may test positive for exposure, but oar not necessarily infectious
groups that are susceptible to TB homelessness, undernourishes or malnourishes, people infected with HIV, misuse drugs, patients with cancer and those takin immunosupresing drugs
anti tubercular drugs fall into two categoris primary and secondary
two effective drugs must be administered at all times
therapy is given in two phases the initial intensive and continuation
initial therapy consists of drugs used in combination to achieve rapid destruction of the TB bacilli and rapid improvement in the patients clinical condition
the first phase of therapy results in reduced morbidity, mortality, and disease transmission – lasts about two months – drugs administered 5x/week – three drugs used at this time
patients in canada with active TB are treated with isoniazid, rifampin, ppurazinamide and ethambutol – for initial 2 months
second continuation phase consists of use of two drugs, drugs may be given daily, or intermittently
Directly observed treatment (DOT) is recommended for patients who have risk factors for non adherence or who are members of population groups with high rates of treatment failure
Isoniazid primary anti tubercular drug and is the most widely used – can be administered either as the sole drug in prophylaxis of TB or in combination
step 1 for diagnosis of tuberculosis perform tuberculin skin test or interferon gamma release assay – Skin test assessed for size of induration, positive value, and risk of disease
step 2 diagnosis of tuberculosis if skin test is positive perform chest x-ray
step 3 diagnosis of tuberculosis if chest x ray shows signs of TB then perform culture of sputum or stomach secretions
first line antitubercular drugs ethambutol hydrochloride (EMB) – isoniazid (INH) – purazinamide (PZA) – rifampin (RMP)
second line antitubercular drugs samikacin sulphate – levofloxacin hemihydrate – mozifloxacin hydrochloride
combination of isoniazid and ethambutol has been used to treat pregnant women with clinically apparent TB without teratogenic complications
Rifamipin is often safe during pregnancy, it is likely to be chose to treat advanced TB
anti tubercular drugs are not as effective against other species of mycobacterium as they are against MTB
contraindications to the use of various antitubercular drugs include severe drug allergy and motor kidney and liver dysfunction
patients are sometimes given a drug to which they have some degree of allergy along with supportive care that enables them to atlas tolerate the medication
isoniazid ADE pyridoxine deficiency and liver toxicity – supplement are often given concurrently
isoniazid interacts with antacids, rifampin, phenytoin, carbamezepine
streptomycin interacts with nephrotoxic and neurotoxic drugs, oral anticoagylants
rifampin interacts with -blockers, benzodiazepines, cyclosporine, oral anticoagulants, oral antihyperglycemics, oral contraceptives, phytoin, quinidine sulphate, sirolimus, thophylline
advise patients taking rifampin to immediately report fever, nausea, vomiting, loss of appetite, jaundice, or unusual bleeding.
rifampin causes oral contraceptives to become unefective
patients taking rifampin may experience red-orange-brown discolouration of the skin, sweat, tears, urine, faces, sputum, saliva and tongue
vitamin B6 is needed to combat peripheral neuropathy associated with isoniazid