Tuberculosis- Level 2

Tuberculosis

A bacterial lung infection that usually involves the lungs, but can infect any organ including the brain, kidneys, and bones.

  • About 25% of the world’s population is infected with TB.
  • Leading cause of death in HIV patients.
  • TB occurs disproportionately in the poor, underserved, and racial & ethnic minorities.

Causative Organism

  • M. tuberculosis (causative organism)
  • Gram-positive, acid-fast bacillus (AFB)
  • Spread via airborne particles

Resurgence of TB

Why is there a resurgence of TB?

High Risk Individuals

  • Born in a foreign country with a high prevalence of TB
    • #1 Asians, #2 Hispanics, #3 Blacks
  • Living or working in institutions (prisons, shelters)
  • Residents of long-term care centers
  • Health care workers
  • IV drug users
  • Homeless; poverty, poor access to health care
  • Residents of inner-city neighborhoods
  • Immunosuppression from any cause (e.g., HIV/AIDS, cancer, long-term corticosteroid use)
  • Diabetes

A patient having more than one of these is even more at risk.

TB Transmission

  • Spread via airborne particles when an infected person:
    • Coughs
    • Speaks
    • Sneezes
    • Sings
    • Laughs
    • Shouts
    • Breathes
  • Particles can remain suspended in the air for minutes to hours, BUT they replicate slowly.
  • ONLY spread via airborne particles
  • Cannot be spread by physical contact, sharing eating utensils, kissing, or other physical contact
  • Brief exposure rarely causes TB
  • Must have close, frequent, and/or prolonged exposure
  • Most immunocompetent adults infected with TB can completely kill the mycobacteria
  • TB is NOT highly infectious

Immune Response to TB

When the patient inhales the organism, macrophages and T lymphocytes act together to try to contain the infection by forming granulomas.

In an immunocompetent adult, the bacteria are most often encapsulated and killed.

If the bacteria are not killed, this can lead to:

  1. Latent TB infection (LTBI): Bacteria are encapsulated and go dormant. No replication. No symptoms. Can later reactivate if the immune system is weakened.
  2. TB disease: Bacteria replicates due to weakened immune system.

In weaker immune systems, the wall loses integrity, and the bacilli are able to escape and spread to other alveoli or other organs.

Latent TB Infection (LTBI) vs. TB Disease

FeatureLTBITB Disease
TB Skin Testpositivepositive
Sputum smearnegativepositive
Infectious?noyes
Symptomsnonepresent

Reactivation of Latent TB Infection (LTBI)

What can trigger reactivation of latent TB infection (LTBI)?

TB Symptoms

  • Initial S/S
    • Cough that becomes productive (mucoid/mucopurulent sputum)
    • Fatigue/malaise
    • Anorexia
    • Unexplained weight loss
    • Fever
    • Night sweats
  • Late S/S
    • Dyspnea
    • Hemoptysis
    • Chest wall pain

TB Complications

TB usually heals without complications, except for scarring

Rare complications can occur if poorly treated or if there is no response to treatment

  • Miliary TB
    • Spreads to other organs via bloodstream – can be fatal if untreated
  • Pleural TB - effusion and empyema
    • Bacteria in pleural space →inflammatory response →fluid or pus in pleural space

Diagnosis

  • TB skin test: TST (aka Mantoux or PPD )
    • Intradermal injection of 0.1 mL PPD antigen on the ventral surface of the arm
  • Reading the Tuberculin Skin Test
    • Read reaction 48-72 hours after injection
    • Measure only induration (not redness)
    • Record reaction in millimeters
    • A positive reaction means that the person has been exposed to TB and developed antibodies
    • Does NOT differentiate between active and latent TB infection

Factors Affecting Skin Test Reaction

Type of reactionPossible cause
False-positiveNontuberculous mycobacteria
BCG vaccination
False-negativeRecent TB infection
Very young age (< 6 months old)
Weakened immune system

Positive Skin Test

What conditions will result in a positive skin test?

Additional Testing

If a person has symptoms of TB, but has a negative skin test, we anticipate additional testing to be ordered.

  • Chest x-ray: Important, but cannot diagnose TB with just a chest x-ray
    • Other diseases can mimic the appearance of TB
    • X-ray might be normal in someone with TB
  • Sputum smear & culture: Definitive diagnosis of TB with culture
    • Take sputum swabs on 3 consecutive days
    • Initially do stained sputum smear for acid fast bacteria (AFB)
    • Then grow sputum culture of M. tuberculosis – can take up to 6 weeks

TB Blood Test

  • Interferon Gamma Release Assay (IGRAs)
    • QuantiFERON®-TB (QFT-GIT)
    • T-SPOT®.TB (T-Spot)
    • If the patient is infected with TB, the lymphocytes in their blood will secrete interferon.
    • Test results are available in a few hours.
    • Requires only one visit
    • Are not subject to reader bias
    • Have no “booster phenomenon”
    • Not affected by BCG vaccination
    • Cost is substantially higher than TST

Goals of Nursing Care

  • Comply with therapeutic regimen
  • Have no recurrence of disease
  • Have normal pulmonary function
  • Take appropriate measures to prevent the spread of disease

Medication Therapy

Two phases:

  • Intensive
  • Continuation

Most patients with TB are treated outpatient.

Treatment for Active TB

Intensive phase: Four medication regimen

Taken daily for 2 months: isoniazid [INH] rifampin pyrazinamide ethambutol

Rationale for Multiple Medications

What is the rationale for the health care provider ordering more than one medication?

Medication Therapy for Active TB

  • Patients should be taught about side effects and when to seek medical attention
  • 3 of the 4 drugs can cause hepatotoxicity
    • Assess for s/s of hepatotoxicity:
      • jaundice/yellow skin, dark urine, clay-colored stools, pruritus
    • Check liver enzymes monthly (AST/ALT)
    • No alcohol
DrugSide effectsNursing implications
Isoniazid (INH)Hepatotoxicity Peripheral neuropathy Vomiting, confusion, headachesMonitor for hepatotoxicity Give pyridoxine, vitamin B6, to decrease peripheral neuropathy Teach/monitor/treat symptoms
RifampinHepatotoxicity Thrombocytopenia Orange discoloration of body fluids (sputum, urine, sweat, tears) á Metabolism of other meds and makes them ineffective such as cardiac meds, birth control pills, steroidsMonitor for hepatotoxicity Monitor platelets Teach patient about orange discoloration of body fluids/ urine/contact lenses Advise female patient’s using oral contraceptives to inform HCP/use another form of contraception
EthambutolOcular toxicity: • Decreased red-green color discrimination • Blurred vision • HeadacheBaseline Snellen vision & color discrimination tests monthly, when on high doses Treat symptoms
PyrazinamideHepatoxicity Polyarthritis HyperuricemiaMonitor for hepatotoxicity Treat symptoms Monitor uric acid levels

Combination pills with multiple medications are available.

Active TB: Treatment Guidelines

  • Be aggressive with treatment
    • Initial phase of treatment
      • Multiple-medication regimen of all 4 meds
      • Administered daily for 2 months
    • Continuation phase of treatment
      • stop ethambutol & pyrazinamide; continue isoniazid & rifampin
      • Administered for 18 weeks

Non-Infectious Criteria

  • Two consecutive (monthly) negative AFB sputum smears/culture
  • Patient has been compliant with adequate treatment for at least 2 weeks
  • Symptoms have improved clinically (i.e., less coughing, afebrile, etc.)

Therapy for Latent TB Infection (LTBI)

  • Individual has been exposed to the bacteria/is infected with M. tuberculosis, but does not have the disease. Will have a positive TB test.
  • Medication helps prevent latent TB infection from developing into active TB disease
  • Only 1 drug is needed d/t the presence of fewer bacteria
  • Usually treated with isoniazid (INH) for 6 - 9 months

Monitoring Treatment Response

After 3 months of therapy, if AFB smears remain positive, and/or symptoms have not improved - what would you expect to happen?

Direct Observation Therapy (DOT)

  • Used with patients who are noncompliant/do not show signs of improvement during/after treatment
  • Noncompliance is a major factor in multidrug resistance and treatment failures
  • Provide drugs directly to the patient; watch them swallow drugs
  • Costly, but essential public health measure
  • If DOT refused, may move to involuntarily treatment in an inpatient

Prevention of Tuberculosis

  • BCG (Bacille Calmette-Guérin) vaccine to prevent TB - currently in use in many parts of the world with a high TB prevalence; given to infants shortly after birth
  • In the United States, rarely used/not recommended due to low risk of infection
  • Can cause false positive TB skin test (TST)
  • Does not affect TB blood test (IGRA)

Nursing Interventions

  • What type of isolation is typically ordered?
  • What PPE is worn?
  • Who wears this equipment?
  • What type of room is required?
  • Patient teaching
    • Cover nose and mouth with tissue when coughing, sneezing, producing sputum; discard appropriately
    • Thorough handwashing after handling sputum-soiled tissues

Airborne Precautions

  • Private Room
  • Negative Pressure
  • Keep door closed

Minimize Exposure

  • Ventilate the room
  • Take ALL medicine
  • Cover mouth when coughing or sneezing
  • Properly dispose of tissues
  • Sleep alone