Tb Flashcards
(28 cards)
most people effected by TB
number of immigrants
poor immune system
malnutrition
intitutional housing
in US the Tb is becoming disease of
elderly
foreign- born from high prevalence
non-white minorities
person with immunodeficency
description Mycobacterium tubercolisis
non-motile rod -shaped baccilus about 2 microns long slowing growing aerobe multiplies faster in presence of oxygen likes to to grow in apices
transmission
almost exclusively transmitted by very small, aerosolized droplets, usually less than 8 to 10 microns in diameter
other mean of contracting TB: ingestion of unpastreurized milk
where does the TB settle
in distal parenchyma
does the body stops TB
No the Tb still multiplies despite the defense mechanism
how tb works
6 to 8 weeks after initial infection, host immune system causes localized inflammation and containment of infection by forming granulomas
intial lesion called Ghon nodule
the combination of initial lesion and the affect regional lymph node is known as Ghon complex
the bodes cell mediated immune response is usually effective in controlling the infection at this point
Pocket of bacteria
it may lie dormant in either the primary Ghon nodule or matastatic sites, sometimes for many years until some event precipitates reactivation
what happens between between primary and reinfection phase
is a dormant or healthy period known as tb with out disease
clinically there is not evidence of TB except positive skin test
reactivation of TB
can take place 10% of infected individual and is most common in two years after initial infection
some factor that contribute to reactivation:aging, malnutrition, alcoholism, diabetes, immunocompromising diseases, silicosis, postpartum period, gastrectomy, chronic hemodialysis, other debilitating disorder.
eventually fibrosis encases the ?
granulomatous lesion and resulting loss of lung
continuous destruction of infected lung parenchyma leads to scarring and loss of lung volume along with destruction of blood vessels and may lead to …..
hypoxemia and hypercapnia and unsual findings
destruction of blood vessels may result in hemoptysis
what to ask for medical history
careful history includes traces outside of US as well as other factors such as country of origin, immunosuppression, institutionalized care and previous or current treatment for TB
TB is considered
a chronic disease with an insidious onset
common complains
fatigue low-grade fever night sweats chronic cough sputum production hemoptysis pleuritic chest pain weight loss symptoms may progress slowly over period of week as to be recognized on in retrospect
physical examination
finding are not specified enough to make diagnosis
can help determine extent of progression and whether other areas of body outside the chest are involved
pulmonary lesions may result in
impaired resonance to percussion
bronchial sounds
coarse crackles
microbiology laboratory provides diagnoses base for TB
they are minimally helpful
WBC count is usually normal
a mild anemia may be present in chronic TB
ABGs
rarely helpful
respiratory acidosis and hypoxemia with end state disease
X-ray PA and lateral shows extent of pulmonary involvment
sputum, CXR are valuable test in diagnoses
the most common abnormality in the chest radiograph is hilar lymph node enlargement
microbiology
a culture needed to confirm TB, can take up 6 weeks to complete the culture
early morning collection is needed or hypertonic solution can be used
also bronchoscopy can be employed if non-invasive procedure didn’t work.
skin testing
an estimate 10-15 million persons in US have dormant M. Tuberculosis infection
mantoux skin test is a intracutaneous injection of a standardize dose of purified protein derivative
CDC classified positive skin testing based on the size of a visible or palpable induration(raised, hardened are)
treatment regimen
organism must be susceptible to at least two of the drugs used
bacteriologic response should occur within the expected time
a single drug should never be added to a program that is failing
drug treatment must continue for a sufficient period of time
patient compliance must be monitor
prophylactic therapy
the therapist observe patient taking the right dose of medication
patient without active disease but positive skin test can decrease the risk to develop the disease by going on isoniazid by taking 6 to 9 month
