Asthma and TB Flashcards

1
Q

What is asthma?

A

Chronic inflammatory disorder of the airways resulting in;

  • Reversible airway obstruction
  • Inflammation, bronchoconstriction, mucus
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2
Q

Describe the pahogenesis of asthma?

A

Environmental Trigger is breathed in leading to inflammation triggered by TH2 cells
This then leads to a type 1 hypersensitivity reaction
This includes;
- Smooth muscle contraction
- Mucus production
- inflammatory cell infiltration
These then lead to: Remodelling = damaged epithelium and increased SM thickness

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3
Q

List some common triggers of asthma

A
Indoor allergens: 
- Pets
- House dust mite 
- Mould/fungus 
Outdoor allergens: 
- Pollens
- Tabacco Smoke
- Pollutants 

Others: Cold, Exercise and medications (BBlockers)

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4
Q

What time of respiratory defect is asthma?

A

Obstructive

FEV1/FVC ratio is usually below 70%

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5
Q

List common symptoms of asthma

A

recurrent:

  • wheeze
  • breathlessness
  • chest tightness
  • cough (usually dry)
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6
Q

what is a wheeze?

A

High pitched, expiratory muscial sound

From narrowed airways (can be compression or obstruction)

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7
Q

Describe distinctive characteristics about a asthmatics cough

A

worse at night
dry
exercise induced

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8
Q

When difficulty breathing is found in response to triggers what can you assess?

A
Respiratory Rate
Tracheal Tug
Recession
Nasal Flaring
Accessory muscle use
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9
Q
How else would you confirm a diagnoses other than assessing;
Respiratory rate
Tracheal tug
Recession 
Nasal Flaring
Accessory muscle use?
A

Full Hx; symptoms?
PMH- Eczma, hay fever
FH- atopy, smoking (if parent smokes during pregnancy, can cause damage to developing lungs)
SH- mould in home, farm, wood burning fire, pets
DH- some medications can make it worse

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10
Q

Respiratory examination would include

A

Inspection
Palpation
Percussion
Asucultation

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11
Q

What can be used to assess respiratory defect?

A

spirometry
Vitalograph; FEV1/FVC
Flow Volume curve
Reversibility- before and after bronchodilator

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12
Q

Treatment of asthma

A

trial Bronchodilators for a month and review

  • do symptoms get better?
  • do their peak flows get better?

if yes, continue to treat as asthma
Spirometry is gold standard for diagnosis

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13
Q

Management of asthma

A

Education - how to use inhalers properly

Prevention- change pillows and bedsheets, fresh air etc.

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14
Q

What is a SABA?

A

Short Acting Beta Agonist
helps relax smooth muscles
quick relief

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15
Q

How does Salbutamol work?

A

Salbutamol is a B2-adrenoreceptor selective agonist it binds to the receptor and reverses or opposes bronchoconstriction

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16
Q

Compare Salbutmaol and Salmeterol?

A

Salbutamol has B2 selective efficacy

Salmeterol has no selectivity but it has higher affinity for B2, its selectivity is therefore based on affinity

17
Q

Describe the mechanism by which BBlockers work?

A

Beta adrenoreceptor antagonists or B-Blockers block the action of the B1 adrenoreceptor in the heart blocking the sympathetic action decreasing the slope of the pacemaker potential in the SA node

18
Q

At what point would a pt need a step up from a SABA?

A

If used more than 3x wk or if nocturnal symptoms more than once a week

19
Q

What is the step up from a SABA?

A

Steriod- preventer
Reduces inflammatory cells
Inhibits inflammatory mediators

20
Q

When is a LABA used?

A

Used in pateitns who still have asthma symptoms despite steroid use
Slower onset or action therefore NOT for acute asthma attack

21
Q

What is the treatment of an acute asthma attack?

A

Oxygen
Salbutamol nebulisers, atrovent nebulisers ‘back to back’
IV access
May need to intubate and ITU admission

22
Q

Details about Mycobacterium Tuberculosis

A

Non-motile rod shaped bacteria
Obligate aerobe
Long-chain fatty (mycolic) acids, complex waxes and glycolipids in cell wall:
- Structural rigidity
- staining characteristics –> Alcohol fast stain
relatively slow growing
Generation time 15h-20h (takes longer to culture)

23
Q

How is TB transmitted?

A

Respiratory droplets

24
Q

what is a giant cell?

What giant cell is present with TB?

A

Multinucelate cells made by fusion of macrophages

Langhans (nucleus around the edges)

25
What is granulomatous inflamation? What is a granuloma? What do granulomas arise with?
Chronic inflammation with granulomas present A granuloma is a collection of immune cells mainly macrophages persistent low grade antigenic stimulation e.g. TB and hypersensitivity
26
What will be in the center of a granuloma in TB?
Caseous necrosis
27
What are sites of Extrapulmonary TB? | Who are they found more often in?
``` Larynx Lymph nodes pleura brain Kidneys Bones & joint Found more often in: - HIV + or other immunosuppressed persons - Young children ```
28
Where are caseating granulomata found?
in the lung parenchyma and mediastinal lymph nodes
29
Compare Latent TB infection and TB disease
Latent TB - inactive, contained tubercle bacilli in the body - TFT or IFN gamma test results usually positive - CXR usually normal - Sputum smears and cultures negative - no symptoms - not infectious Not a case of TB TB Disease - Active, multiplying tubercle bacilli in the body TST or blood test results usally positive - CXR usually abnormal - Psutum smears and cultures may be positive - Symptoms such as cough, fever, weight loss - often infectious before treatment A case of TB
30
What is the test for TB?
The Mantoux test/Tuberculin sensitivity test tuberculin injected intradermally. the induration is read 48-72 hours later Cheap subject to interpretation
31
what is interferon gamma releasing assays?
used to support the diagnosis of TB Detection of antigen specific IFN-gamma production T spot TB Quantiferon Gold No cross-reaction with BCG cannot distinguish between latent and active TB Similar problems with sensitivity and specificity