What lung fields are usually the most affected by Tuberculosis (TB)? - What size of Tuberculosis (TB) can reach the alveoli - what factors affect size of droplets?

1-5 um can affect the right middle/lower lobe - droplet sizes > 5cm are trapped by mucosa and removed by cilia - Humidity, Temp, ventilation affect droplet size

Mod 9 Tuberculosis Flashcards by Derrick Chuong

What is the most common association/definition of Tuberculosis?

TB is a chronic infectious disease caused by nonmotile, nonspore, forming bacteria belonging to the family Myocobacteriaceae (M.Turberculosis).

M. TB is the most important agent in any human agent of disease
primarily affects the lungs but can invade any part of the body

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Why is Mycobacteriacaeae an important agent of TB?

Time required to produce a new gen of bacteria is fast (x18-24h)

Can exist in both aerobic and anaerobic environments
Can survive within granuloma, macrophage, and cytoplasm

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How does Tuberculosis spread (TB) spread?

Air droplets via cough, sneeze, or speaking (airborne pathogen)

close contacts are at highest risk of infection (>8h or intense contact)

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What lung fields are usually the most affected by Tuberculosis (TB)?

What size of Tuberculosis (TB) can reach the alveoli
what factors affect size of droplets?

1-5 um can affect the right middle/lower lobe

droplet sizes > 5cm are trapped by mucosa and removed by cilia
Humidity, Temp, ventilation affect droplet size

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What happens to patients who contract Tuberculosis (TB) but remain unaffected?

TB remains dormant -> latent TB infection (LTBI)

bc body can’t get rid of it
few cases of infection directly progress to pulmonary disease

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What population groups are most affected by Tuberculosis (TB)?

Children < 4 yrs
Immunocompromised

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Is the initial stage of infection for Tuberculosis (TB) fast or slow?

They multiply Slow (2-12 wks)

cell division q25-35hrs

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What role do granulomas have with Tuberculosis (TB) and why is it important to pay attention to?

Granulomas develop around the bacteria to limit bacteria multiplication to other sites

Granulomas = clusters of WBC
Granulomas secrete pro and anti inflammatory cytokines
This phase establishes latency of the infection

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What usually develops in immunocompromised hosts with Tuberculosis (TB)?

Fibrosis and calcifications occur due to primary progressive TB

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When is primary Tuberculosis (TB)/active TB usually experienced?

The first 2 years following infection

Dormant bacteria may persist before reactivated following a temporary or permanent immune depression

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What are the 3 categories of Tuberculosis (TB)?

Primary TB aka primary infection stage
Latent TB aka post/dormant TB
Disseminated TB aka extrapulmonary/Miliary/TB-disseminated

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What is Tuberculosis (TB) often mistaken for?

Pneumonia

Inflammatory response is
Symptoms can be mild-severe
Conincides w/a positive tuberculin reaction

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What are initials lesions that encapsulate Tuberculosis (TB) called?

Ghon nodules

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What is the immune response to Tuberculosis (TB)?

Similar to pneumonia

Immune system responds to infected area by producing protective cell walls called granulomas or tubercle
Granuloma encapsulate TB halting spread of infection
Body begins healing process
Fibrotic and calcified tissue replace granuloma

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What is Caseous necrosis?

Dead cells that are not completly digested since they’re trapped within a granuloma

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What does a Granuloma consist of

Central core with caseous necrosis and TB bacilli

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Why are Fibrotic and calcified tissue replacement a problem following a granuloma?

Can cause the Parenchyma to retract and scar leading to a restrictive component

if too close to bronchi, could cause a bronchiectasis to occur

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What are the clinical manifestations of Primary Tuberculosis?

TB can occur w/o clinical signs and symptoms
Or resemble mild resp tract infection i.e pneumonia

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What can the infection caused by primary Tuberculosis (TB) progress to?

Pleural Effusions
Fever and Cough
Pain
Dyspnea

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What locations of the lung fields are affected by Secondary Tuberculosis (TB)?

When does it reactivate?

Secondary TB is contagious and reactivates from mycobacterial LTBI.

located where O2 concentrations are the highest
Apices are primarily affected, in some cases the base depending on position

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What are the most frequently detected signs/manifestations of Secondary Tuberculosis (TB) or LTBI?

Low grade fever
Asthenia (physical weakness/lack of energy)
Anorexia
Night sweats
Mucopurulent cough last > 2-3 wks
Hemoptysis
Pleuritic chest pain

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What does progressions of Tuberculosis (TB) look like after infection?

i.e lab findings, CxR, pathologies that result etc etc.
Which 3 are primarily seen?

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Ghon Complexes appear in the hilar region (tubercles + lymph nodes)
Cavity formation (from tissue fibrosis/calcification = scarring)
Retraction of lung segments or lobe

What pathology does the following CxR represent?

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Cavitation caused by Miliary TB

What are the 3 tests used to diagnose Tuberculosis (TB)

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QuantiFERON-TB Gold Test
Mantoux tuberculin skin test
Sputum Sample via Xpert MTB/RIF assay or Acid fact bacilius/AFB test)

What safety requirements need to be met for any test procedure with Tuberculosis (TB)?

Patient muse be in a airborne isolation room

What is the induction method to gather a sputum sample for a patient suspected with Tuberculosis (TB)?

1. Sputum induction w/hypertonic saline (3%) 2. Have pt breath in deeply w/SVN 3. Collect sample in cup when patient coughs

What is the purpose of 3% hypertonic saline?

1. To induce a cough for a sample 2. Increase intravascular fluid volume (treat hyponatremia) 3. hypertonic saline w/mannitol can be indicated to reduce ICP

When is sputum induction indicated for a Acid fact bacillus test (AFB)?

Useful for Pts who are either sputum smear negative or unable to produce sputum

What drug is needed for any Tuberculosis (TB) that requires sputum collection?

Salbutamol because the testing procedure may cause broncospasm

What are the benefits of using the Xpert MTB/RIF assay method for sputum sampling? - How soon are results available?

Can simultaneously detect TB, multi drug resistant (MDR) TB in > 2hrs - Test detects DNA sequences specific to myobacteriaceae tuberculosis

What is QuantiFERON TB Gold Test? - How soon are results available?

The gold standard method performed by whole blood test - Used to diagnose **Mycobacterium Tuberculosis (TB)** and latent TB infection - Results available after 24 hrs - Can't distinguish active vs latent infection - Useful in that Bacillus Calmette guerin vaccine (BCG) vaccinations will not mask results

What is the Bacillus Calmette Guerine (BCG) vaccine and when should it be used?

Vaccine against TB, given to babes asap after birth in countries w/high TB/leprosy fates

What is the Mantoux tuberculin skin test? - What do "wheal" results indicate?

Injection of purified protein derivative (PPD)

How long is the standardized treatment period for Tuberculosis (TB)?

6 months in total, split into 2 phases. 1. Intensive/induction phase (2 months) 2. Continuation phase (4 months) Treatments are Direct Observed Therapy (DOT)

What are the treatments during the intensive/induction phase for Tuberculosis (TB)?

4 Anti TB drugs are used daily: 1. Isoniazid 2. Rifapin 3. Ethambutol 4. Pyrazinamide

What are the treatments during the Continuation phase for Tuberculosis (TB)?

Weaned down to 2 drugs daily. 1. Isoniazid 2. Rifampin - Treatment dosing changes after 1-2 months. - First 1-2 months = QD - After 1-2 months = BID until 9 months are over

What does Direct Observed Therapy (DOT) mean in relation to Tuberculosis (TB) treatments?

All patients must be observed to be taking their meds

What are prevention measures for Tuberculosis (TB)?

Admin of Bacille Calmette Guerine (BCG) vaccine - A vaccine used as an active immunizing agent against tuberculosis and in cancer immunotherapy (a strain of M.Bovis) - Not recommended for pts w/HIV

What does it mean when a person has Latent Tuberculosis (LTBI)?

No S & S and only have immunological markers. - aprox 10% of affected develop TB, 50% within 2 years of infection. 90% don't develop the disease - Impossible to know if LTBI pts still harbor living myobacteria

What are Treatments for Latent Tuberculosis (LTBI)

Preventative treatments can reduce the risk of development of disease. The current gold standard is: - 9 months isoniazid and 4 months rifampicin, **or** - 3 months of a combination of isoniazid and rifampicin

What is a common issue with Tuberculosis (TB) treatments?

Early misdiagnosis or delayed diagnosis - Symptoms of TB present like fevers and have a nonspecific presentation (signs vary to involved tissue)

What is Miliary Tuberculosis (TB)?

Spread of TB/Escape from the tubercle and travels to other sites using the blood stream and lymphatic system

Where is Miliary TB most often found?

O2 rich organs in the body: - Brain - Kidneys - Long bones - Genitalia - Meninges

Complications of Tuberculosis (TB)

What is Extrapulmonary Tuberculosis?

Tb that involves other organs, often misdiagnosed

What TB Outcomes are expected from the resulting Structural changes: Alveolar consolidation?

Pneumonia

What TB Outcomes are expected from the resulting Structural changes: Alveolar capillary destruction?

**Shunt and Decreased DLCO** - DLCO = A measurement to assess the lungs' ability to transfer gas from inspired air to the bloodstream

What TB Outcomes are expected from the resulting Structural changes: Caseating tubercles?

Retraction of surrounding tissue

What TB Outcomes are expected from the resulting Structural changes: Cavitation?

- Visible on CxR, seen as tissue destruction by granulomas (immune cells) - Higher bacterial loads - Risk of hemoptysis (coughing blood) - Increased WOB

What TB Outcomes are expected from the resulting Structural changes: Fibrosis and Calcification?

Decreased flows and volumes on PFT - Increased WOB

What TB Outcomes are expected from the resulting Structural changes: Distortion and dilation of bronchi?

Bronchiectasis

What TB Outcomes are expected from the resulting Structural changes: Pleural effusions and inflammation, Destruction, cavitation, and fibrosis all?

Increased WOB

What does advanced TB result in?

Cavitation (air filled spaces) - leads to areas of **regional hyperinflation) or increased compliance in cavities juxtaposed to stiff fibrotic areas - Remember, generally TB decreases compliance but cavitation's increase the compliance in the cavitation's

Mod 9 Tuberculosis Flashcards

(53 cards)