Chapter 18 Patho Flashcards
- TB has three classifications
Primary TB also called primary infectious stage.
Postprimary TB also called reactivation, reinfections, and secondary TB.
Disseminated TB also called extrapulmonary , miliary, and tuberculosis-disseminated
- Primary TB tuberculosis
(primary infection stage)
~ 4 week period
~ initial response (of lungs) is inflammation similar
to pneumonia
- which of the following are know as the first stage of TB?
- primary tuberculosis
- primary infection stage
- primary infection stage
~ a large influx of polymorphicnuclear leukocytes
and macrophages move into the infected area to
engulf - but not fully kill - the bacilli
~ this action also causes the pulmonary capillaries
to dilate, the interstitium to fill with fluid, and the
alveolar epithelium to swell from the edema fluid
~ eventually, the alveoli become consolidated
- PPD
purified protein derivative
- tubercle
~ unlike pneumonia, the lung tissue that surrounds
the infected area slowly produces a protective cell
wall
~ AKA ‘granuloma’
~ takes about 2-10 weeks to form
- Ghon nodule
name for tubercles when detected on a chest xray
- Ghon complex
as disease progresses the combination of tubercles and the involvement of the lymph nodes in the hilar region
- TB bacilli
may remain dormant for months, years, or life
- latent TB
~ patients with dormant TB do not feel sick or have
any TB related symptoms
~ they are still infected with TB but do not have
clinically active TB
- post-primary TB
~ a term used to describe the reactivation of TB
months or even years after the initial infection has
been controlled
AKA:
- reactivation TB
- reinfection TB
- secondary TB
- risk factors
~ malnourished individuals ~ institutional housing ~ people living in overcrowded conditions ~ immunosuppressed patients ~ Human Immunodeficiency Virus (HIV) TB is leading cause of death for HIV ~ alcohol abuse
- uncontrolled TB
~ further growth of the caseous granuloma tubercle develops ~ pt progressively experiences more severe symptoms: - violent coughing episodes - greenish/ bloody sputum - low grade fever - anorexia - weight loss - extreme fatigue - night sweats - chest pain
- consumption
~ earlier name for TB
~ based on the gradual wasting away of the body
~ patient is highly contagious at this point
- disseminated TB
infection from TB bacilli that escape from a tubercle and travel to other sites throughout the body by means of the bloodstream or lymphatic system
- most common location
~ is the apex of the lung (↑ PaO₂) ~ other O₂ rich areas include: - regional lymph nodes - kidneys - long bones - genital tract - brain - meninges (spine)
- complications
~ hemoptysis ~ pneumothorax ~ bronchiectasis ~ extensive pulmonary destruction ~ malignancy ~ chronic pulmonary aspergillosis ~ mental deterioration ~ permanent retardation ~ blindness ~ deafness
- military TB
large number of bacilli are freed into the bloodstream, numerous small tubercles - about the size of a pinhead - scatter throughout the body
- pathological/ structural changes
~ alveolar consolidation ~ A/c membrane destruction ~ caseous tubercles or granulomas ~ cavity formation ~ fibrosis and secondary calcification of the lung parenchyma ~ distortion and dilation of the bronchi ~ ↑ bronchial secretions
- etiology/ epidemiology
~ TB is one of the oldest diseases known to man and
remains one of the most widespread diseases in
the world
*even found in mummies from ancient Egypt
~ one of the top 3 causes of death among women
aged 15-44, worldwide
~ leading killer of HIV patients
*25% of all deaths
- bacteria
in humans, TB is primarily caused by the bacteria Mycobacterium tuberculosis
- transmission
~ within aerosol droplets produced by coughing,
sneezing, or laughing
~ can remain suspended in the air for several hours
after a cough or sneeze
~ may possibly be ingested in unpasteurized milk
from cattle infected with the TB pathogen
Mycobacterium Bovis
- Montoux tuberculin skin test
~ most frequently used diagnostic method for TB
~ purified protein derivative (PPD)
~ results in 48/72 hours
~ an induration (wheal) of ≥10mm is considered
a positive result
- acid-fast bacteria
(sputum smear) ~ Ziehl-Neelsen stain reveals bright red acid-fast bacilli against a blue background ~ fluorescent acid-fast stain reveals luminescent yellow-green bacilli against a dark brown background this is becoming #1 choice
- nontubeculous acid-fast mycobacteria
associated with COPD are Mycobacterium avium & Mycobacterium Kansasi
- M. tuberculosis
~ grows very slowly
~ up to 6 weeks for colonies to appear in culture
- QuantiFERON-TB Gold Test
~ whole-blood test for diagnosing M. tuberculosis
infection, including latent TB infection
~In 2005 the US food and Drug administration FDA approved for QFT-G test.
- peripheral edema & venous distention
~ polycythemia ~ cor pulmonale ~ distended neck veins ~ pitting edema ~ enlarged/ tender liver
- chest assessment
~ ↑ tactile/ vocal fremitus ~ dull percussion note ~ bronchial breath sounds ~ crackles/ wheezing ~ pleural friction rub ~ whispered pectoriloquy
- hemodynamic indices
~ ↑ CVP ~ ↑ RAP ~ ↑ PA ~ N PCWP ~ ↑ PVR
- abnormal labs
~ positive PPD
~ positive sputum acid-fast bacillus stain test
~ positive ABF sputum culture
~ positive quantiFERON-TB Gold Test
- chest xray
~ opacity ~ Ghon nodule ~ Ghon complex ~ cavity formation ~ cavitary lesion containing an air-fluid level ~ pleural effusion
- 6-month treatment protocol
first 2 months (induction phase) daily: ~ isoniazid (INH) ~ rifampin ~ pyrazinamide ~ ethambutol or streptomycin next 4 months, either daily or twice weekly ~ isoniazid ~ rifampin
- 9-month treatment
months 1-2, daily: ~ isoniazid ~ rifampin months 3-9, twice weekly: ~ isoniazid ~ rifampin
- isoniazid & rifampin
1st line agents prescribed for the entire 9 months
- isoniazid
considered to be the most effective 1st-line antituberculosis agent
- prophylactic use of isoniazid
~ often prescribed as a daily dose for 1 year to those
who’ve been exposed to TB bacilli or who
demonstrate a positive tuberculin response
(even when the acid-fast sputum stain is negative)
- resistance
when TB bacterium is resistant to one or more of these agents ≥3 more antibiotics must be added to the treatment regimen, and duration should be extended
- Directly Observed Therapy
(DOT)
a major problem with TB therapy is noncompliance on the part of the patient to take the TB medication as prescribed.
therefore, ingestion of the medication must be directly observed by a responsible individual
- Which of the following are known as the first stage of tuberculosis?
- Reinfection tuberculosis
- Primary tuberculosis
- Secondary tuberculosis
- Primary infection stage
a. 2 only
b. 3 only
c. 1 and 3 only
d. 2 and 4 only
d
- What is the name of the protective wall that surrounds and encases lung tissue infected with tuberculosis?
- Miliary tuberculosis
- Reinfection tuberculosis
- Granuloma
- Tubercle
a. 1 only
b. 3 only
c. 4 only
d. 3 and 4 only
d
- The tubercle bacillus is:
- Highly aerobic
- Acid-fast
- Capable of surviving for months outside of the body
- Rod-shaped
a. 2 only
b. 4 only
c. 2 and 3 only
d. 1, 2, 3, and 4 only
d
- At which size wheal is a tuberculin skin test considered to be positive?
a. Greater than 4 mm
b. Greater than 6 mm
c. Greater than 8 mm
d. Greater than 10 mm
d
- Which of the following is often prescribed as a prophylactic daily dose for 1 year in individuals who have been exposed to tuberculosis bacilli?
a. Streptomycin
b. Ethambutol
c. Isoniazid
d. Rifampin
c
