TB Causative Organism
Mycobacterium Tuberculosis
gram positive, acid fast bacillus
Why is there a resurgence of TB currently?
antibiotic resistant bacteria have developed and antibiotic treatemnt courses are lengthy and difficult
How is TB transmitted?
Ariborne droplets from coughing, speaking, sneezing, and singing
Pts can show TB symptoms _____________ after exposure, and so need to be tested several times
2-13 weeks
About Mycobacterium Tuberculosis
-______philic
-has an affinity for ______
-spreads via______ to ______, _____, _____, and _____
-aerophilic
-lungs
-spreads via lymphatic system to kidneys, bone epiphyses, cerebral cortex, and adrenal glands
How doe TB remain dormant? what is the name for dormant TB?
inflammatory response forms "wall" around organism along with macrophages & other cells to form granulomas, which inhibit replication and spread. Body has the ability to "wall it off" and prevent it from becoming active; eventually becomes calcified mass
What percentage of adults are able to fight off TB infection?
70%
What percentage of those with latent TB go on to develop active infection later?
5-10%
Does TB replicate slowly or quickly?
slowly
Once TB enters lungs, where does it lodge?
alveoli
How long can Mycobacterium nuclei remain airborne?
minutes to hours
Does a brief exposure to TB usually cause infection? How close do you need to be to acquire TB (typically)
No. Need frequent or prolonged exposure.
6 inches
How is TB not spread? (4)
touching
kissing
sharing utensils
other physical contact
TB initial signs and symptoms
-how soon develop?
-what are they? (5)
-develop 2-3 weeks after infection
1) fatigue
2) low-grade fever at night
3) anorexia
4) chest pain
5) bad cough (3 or more weeks)
TB late symptoms (2)
-r/t what?
1) hemoptysis
2) dyspnea
-r/t pleural effusion
TB: Factors that influence likelihood of infection (4)
1) Number of organisms expelled into air
2) concentration of organisms w/in a space
3) length of time of exposure
4) immune system of exposed person
Who is highest risk for developing TB?
HIV patients
How has HIV affected the spread of TB?
TB declined worldwide until mid-1980s when HIV emerged
Leading cause of death in patients with HIV
TB
TB infection vs disease
Infection: occurs when M. tuberculosis inhaled but an effective immune response renders the bacteria inactive
Disease: defined as active bacteria that multiply and cause clinically active disease
Why does TB disease occur rather than infection?
occurs if the initial immune response is inadequate
Is Latent TB Infection contagious?
No, but the active disease is.
Who else is at risk for TB, besides those with HIV? (7)
1) immunosuppressed
2) DM
3) IV drug users
4) homeless
5) foreign-born (especially asian)
6) previous TB
7) chronic disease
What is Primary TB?
when active disease develops within first 2 years of infection
Latent TB Infection (LTBI)
-symptomatic?
-skin test?
-CXR?
-Reactivation?
-Treatment?
-not symptomatic
-skin test can be positive
-CXR will be negative
-Reactivation possible if host defense mechanisms impaired
-Still needs to be treated b/c it could progress to transmissible disease
Triggers that can reactivate LTBI (7)
1) HIV (greatest risk)
2) immunosuppression
3) DM
4) poor nutrition
5) aging
6) pregnancy stress
7) chronic disease
Reactivation TB (define)
TB disease occurring 2 or more years after initial infection
TB: Nursing Interventions with the infected patient
-Precautions (5)
-Who must be notified
Precautions:
1) HEPA masks
2) airborne isolation room
3) teach patient to cover nose/mouth with tissue when coughing, sneezing
4) dispose of sputum by burning, trashing or flushing
5) always wash hands after handling sputum-soiled tissues
- MUST notify pu
Worst complications of TB (4)
1) PLEURAL EFFUSION
2) EMPYEMA
3) TB PNEUMONIA
4) MILIARY TB
What causes pleural effusion s/t to TB?
bacteria and exudate building up as inflammatory response in pleural space
What causes empyema s/t to TB?
large amounts of tubercular organisms in pleural space fill it with pus
What cuases pneumonia s/t to TB?
large amounts of discharged bacilli from granulomas in to the lungs or lymph nodes
Miliary TB: define
-caused by primary or reactivated TB?
Definition: systemic TB, involves many organs simultaneously infected with TB
-can occur as result of primary TB or reactivation of latent TB.
Standard method to screen for TB infection
-what is the name of the test?
-what is the material used?
-How much?
-Process
-When is it read?
Name: tuberculin skin test (TST or Mantoux)
Uses: purified protein derivative (PPD)
How much: 0.1 mL of PPD
Process: injected ID to produce 6 mm wheal on dorsal forearm
Read: 48-72 hours later
What is induration?
the hard, white raised area
What does a positive TB skin test indicate?
positive only means person exposed and antibodies have developed--no differentiation between active or latent infection
What is not induration?
erythema
How many mm induration considered positive in low-risk person?
15 mm induration
How many mm induration considered positive in moderate risk persons
10 mm induration
How many mm induration considered positive in high risk persons?
5 mm induration
What risk level is a healthcare worker considered to be for TST test?
moderate risk
Who is considered to be high risk for TB when doing TST?
immunocompromised cancer or HIV patients
TST: What can cause a false positive reaction? (2)
1) may have received the BCG vaccine (live)
2) may have a NON-tuberculosis mycobacterium infection
TST: What can cause a false negative reaction? (7)
1) recent TB infection (antibodies develop 2-12 weeks after initial exposure)
2) very young (< 6 months old)
3) previously infected but with waning immune response
4) anergy (lack of immune response)
5) OVERWHELMING TB infection
6) very old TB infection (
Does positive reaction to PPD mean person has TB?
No, just exposed--requires sputum culture to confirm; cannot tell if dormant or active just by PPD reaction
Who needs to get the two step TST? Why?
Who: recommended INITIAL testing for health care workers and others who will need repeated tests in the future
Why: a negative 2-step prevents misinterpretation in future tests, since later tests that are positive indicate new infections
Two-step TST: why might second test result be different from first?
previously-infected person may have negative first test d/t waning immune response, but positive second test d/t the "boost" effect of first test
Two step TST: what does two consecutive negatives mean?
two consecutive negatives confirm no present or PREVIOUS infection
If the skin test is positive, what is the next step to confirm dx?
Sputum culture if patient has symptoms
If a person has TB-like symptoms but a negative skin test, then the HCP would likely order what?
sputum culture; or a CXR if unable to get culture
Diagnostic studies needed to positively diagnose TB disease
1) 3 sputum cultures obtained on 2-3 consecutive days; culture all specimens, even if smear is negative.
TB sputum culture can take up to _____________ due to _________
8 weeks, slow growing organism
TB Blood serology SCREENING test (aka)
QuantiFERON-TB (QFT) test
QFT test: process
Blood is obtained from patient and placed in container with mycobacterial antigens. If the patient is infected with TB, the lymphocytes in the blood will recognize these antigens and secrete interferon, a cytokine produced by lymphocytes.
QFT test results are available in _________ and are not affected by _______________
a few hours, the BCG vaccination.
TB: Can a chest x-ray diagnose?
No, can only tell us if there is a shadow in lung
TB: Treatment Approach
-Aggressive or Conservative?
-2 Phases
-Aggressive
-Phases: Initial and Continuation
Initial TB Tx:
-How long?
-Drugs (4)
-Pregnant or Liver Disease?
How Long: 2-month
Drugs: 1. isoniazid (INH), 2. rifampin, 3. pyrazinamide (PZA), 4. ethambutol
Pregnant or Liver Disease: no PZA
Continuation TB Tx:
-How long (normal, pregnant, liver disease)
-Continue until?
How long: normal - 18 weeks; pregnant or liver disease - 31 weeks
Continue until: monthly cutlures come back negative
LTBI: Does patient get treated? With What? For how long? Why?
YES. Must treat to prevent possibility of becoming active. Only Isoniazid (INH) for 6-9 months as fewer bacteria make treatment easier
TB Nursing Care: Goals (4)
1) compliance with therapy
2) have no recurrence
3) normal pulmonary function
4) prevent spread through appropriate measures
isoniazid (INH)
-Side Effects (3)
SE:
1) noninfectious hepatitis
2) peripheral neuropathy
3) hypersensitivity.
Labs (3) and S&S (4)to monitor with INH treatment. How often?
Labs: Liver enzymes, BUN, Creatinine
S&S: of hepatitis: jaundice, dark urine, clay colored stools, pruritus
Monthly
Should INH be taken with meals
No. Take on empty stomach.
Supplement to give with INH. Why?
Give B6 pyridoxine as prophylactic against peripheral neuropathy
Foods to avoid when taking INH. Why?
Foods that contain tyramine and histamine: tuna, aged cheese, red wine, soy sauce, yeast extracts
Causes flushing
rifampin (aka)
Rifadin
rifampin:
Side Effects (4)
SE:
1) hepatitis
2) GI disturbances
3) Orange discoloration of body fluids (sputum, urine, sweat, tears)
4) increased metabolism of other meds and makes them ineffective (e.g., cardiac meds and steroids)
Pt. education about rifampin (3)
1) orange discoloration of fluids/ urine.
2) Discolor contact lenses
3) drink lots of water
PZA (aka)
pyrazinamide
PZA: Side Effects (4)
1) Hepatoxicity
2) polyarthritis
3) Skin rash
4) hyperuricemia
PZA: monitoring
-Labs: (1)
-S&S: (5)
Labs: uric acid levels
S&S: of hepatitis (jaundice, yellow skin, dark urine, clay colored stools, pruritus).
Major SE of INH, rifampin and PZA
nonviral hepatitis--always monitor liver function
ethambutol (aka)
Myambutol
ethambutol: Side Effects (2)
1) Retrobulbar neuritis (decreased red-green color discrimination
2) skin rash
ethambutol: tests to monitor
-Baseline? (1)
-Monthly?
Baseline: Snellen vision
Monthly: color discrimination monthly when on high doses
Pt. teaching for ethambutol (2)
1) ADVISE pt. that driving may be an issue
2) stay out of light
If the M. tuberculosis is susceptible to all of the 4 main drugs, which drug is dropped?
When?
ethambutol
When: Pt. will get all four meds for at least 8 weeks; after 8 weeks if treatment is shown effective, ethambutol can be dropped
Can a patient with a positive TB culture go home?
Yes, IF contacts in the home have previously been exposed.
Home instructions for TB patients: (5)
1) Room s/b well ventilated
2) sleep alone
3) spend time outside
4) restrict visitors
5) avoid public transport and places
When can home restrictions be eased for a TB patient?
Can remove most restrictions once sputums are negative.
Who must the nurse notify when d/c a TB patient home? Why?
public health department, so PHN can f/u
How long is patient with sputum smear-positive TB considered infectious after starting treatment?
First 2 weeks.
Are most people with TB treated as inpatients or outpatients?
Outpatient
How many neg sputum cultures needed to confirm TB tx success?
3 different
TB Drug Therapy: Teaching
-lifestyle
-Adeherence
Lifestyle: no alcohol d/t hepatotoxicity, no smoking, no acetaminophen
Adherence: esp., the right dose at the right time for entire course
What percentage of TB disease patients relapse?
5%
MDR-TB (aka)
Multi Drug Resistant TB
DOT (aka)
Direct Observation Therapy
If no response to treatment after 3 months (positive culture or persistent symptoms), what is next step?
reevaluate for MDR-TB or nonadherence to drug tx
What is done if it is MDR-TB?
fluoroquinolones "oxacin
What is done for noncompliance?
consider DOT
DOT: what is it
Provide drugs directly to the patient and watch patient swallow drugs.
What is done if pt refuses DOT?
may have to put involuntarily in treatment facility to protect the community
Classification System for TB
0
1
2
3
4
5
O-no exposure or history
1 - history of exposure but negative on skin test
2 - positive reaction to skin test, negative bacteriologic studies and no clinical or radiographic evidence of active infection
3 - clinical, bacteriological, or radiographic evide
What is POTS disease?
TB in the spine
How do you obtain a sputum specimen for TB testing?
1st thing in AM.
Take 3 deep breaths, hack deep cough
Tell Pt not to brush teeth, drink anything, etc.
Use sterile cup.
TB vaccine: name
Bacille Calmette-Guerin (BCG)
IS TB vaccine used in US?
Not usually, except for very select individuals