Tuberculosis Flashcards
Types of tests to confirm TB diagnosis?
skin test/mantoux test (forearm) + chest xray –> if positive results, but no symptoms, then inactive TB and requires prophylaxis.
Prophylactic tx for TB?
INH for 9 months
What are the three uses for the Mantoux test?
- diagnosis of latent TB infection
- assisting in the diagnosis of TB
- epidemiological tool
If a patient has known or suspected TB, should they go to emergency treatment?
yes, hospitalized in a single negative pressure room, placed on respiratory precautions.
What are the skin test results?
> 5 mm = HIV + Recent contact with active TB, immunocompromised
> 10 mm = residents, employees of long-term care facilities, IVDU, recent immigrants < 5 yrs
> 15 mm = general public without known risk factors
What can be the cause of a false negative test?
secondary ill patients, those with impaired cell mediated immunity, inappropriate technique/reading
What can be the cause of a false positive test?
history of BCG vaccination, exposure to non-TB mycobacteria, inappropriate technique reading
What is the latent TB state?
inactive stage, pt is infected, but not contagious so it cant spread
what is the treatment in latent TB?
isoniazid QD or twice weekly for 9 months.
if INH resistant, give Rifampin qd for 4 months
symptoms of active TB?
cough, fever, night sweating, weight loss
how is TB spread?
Lungs - chest pain, coughing up blood, productive cough, prolonged cough
Central - appetite loss, wt loss, fatigue, fever
Skin - night sweats, pallor
in patients with TB, what drugs should be avoided?
Live vaccines, TNF alpha inhibitors
Treatment for active TBÉ
- INH
- if INH resistance > 4% = INH + Rifampin + PZA + Ethambutol
- if INH resistance < 4% = INH + Rifampin + PZA
- if no resistance, INH + Rifampin + ethambutol
Drugs of choice if rifampin resistant?
INH + PZA + EM + a quinolone or Streptomycin
Drug therapy in elderly > 65 or if at risk of hepatotoxicity?
INH + RIFAMPIN + ETM qd x 2 months, then INH + Rifampin daily x 7 months
should all TB drugs be taken with or without food?
without food (empty stomach 30 min before food)
in pregnancy, should anti-TB drugs be withheld?
no, due to the risk of TB to the fetus.
what are the TB medications?
Isoniazid (INH)
Rifampin/Rifabutin
Ethambutol
Pyrazinamide
Streptomycin
FQs
Which drug can cause optic neuritis, severe vision loss and often permanent/irreversible?
Ethambutol
Which drug lowers vitamin B6 levels?
Isoniazid (INH)
which drug is chemically related to INH?
pyrazinamide
which drug can cause hepatotoxicity?
pyrazinamide
which anti-TB med can cause orange-red urine, body fluids, stool, tears or discoloration?
rifampin/rifabutin
Which anti-TB drug is a strong cyp inducer (3a4, 2d6, 2c9, 2c19)?
rifampin/rifabutin
which anti-TB drugs do not cause liver toxicity?
ethambutol, spectinomycin, streptomycin
Side effects of INH
peripheral neuropathy (dose-related) due to Vit b6 deficiency, sideroblastic anemia (treatment for this is vitamin b6 25-50 mg)
what should you monitor when someone is taking INH?
LFTs (AST) > 3 times the upper limit.
what are clinical hepatitis symptoms?
can occur within weeks to months of INH. monitor: fatigue, flu-like symptoms, anorexia, nausea w/ or w/oi vomiting
when should hepatotoxic drugs be withheld?
if liver enzymes exceed 5 times the upper limit of normal, or in presence of symptoms of hepatitis (nausea, vomiting, abdominal pain, dark urine, scleral icterus)
