Session 6 - TB And Asthma

Question 1

Describe the microbiology of mycobacterium tuberculosis

Answer 1

• Can only be stained using acid fast stains
• obligate aerobe
• relatively slow growing
• non-mobile rod shaped bacteria

Question 2

Describe the pathology of TB

Answer 2

• mycobacterium TB is ingested by macrophages, but escapes from phagolysosome to multiply in cytoplasm
• intense immune response causes local tissue destruction
• accompanied by cytokine-mediated systemic effects

Question 3

What may pulmonary TB present with?

Answer 3

• Chronic cough
• Haemoptysis
• Fever + Weight loss
  Or as recurrent bacterial pneumonia

Question 4

What are some other sites of the body that TB may infect other than the lungs?

Answer 4

• Meninges
• Kidney
• Lumbrosacral spine
• Large joints

Question 5

What will a chest X-ray show if Post primary TB is present?

Answer 5

Pulmonary shadowing that may be patchy solid lesions, cavitated solid lesions, streaky fibrosis or flecks of calcification

Question 6

What is miliary TB?

Answer 6

• bacilli spread through the blood stream
• will be diffusely spread throughout the lungs
• headaches will indicate meningeal involvement

Question 7

What is the treatment plan for TB?

Answer 7

Four drugs for two months 
- Rifampicin 
- Isoniazid 
- Pyrazinamide 
- Ethambutol
After which first two are continued for a further four months

Question 8

Why are four different drugs given simultaneously?

Answer 8

To try and reduce the risk of resistance

Question 9

What are some of the side effects of TB medications?

Answer 9

• Hepatitis
• Acute Renal Failure
• Rash
• Arthralgia
• Peripheral neuropathy

Question 10

What are some of the issues with the BCG vaccine?

Answer 10

• Variable efficacy

- Efficacy only lasts 15 years max

Question 11

Which groups are at particular risk of TB?

Answer 11

• HIV patients - Asian ethnicity
• Malnutrition - diabetes
• Silicosis
• People living in overcrowded places
• IV drug users
• Chronic lung disease

Question 12

Define Asthma

Answer 12

A chronic inflammatory disorder of the airways resulting in reversible airway obstruction, inflammation, bronchoconstriction + mucus build up

Question 13

Which inflammatory cells are important in causing the airway disorder in asthmatics?

Answer 13

• Mast Cells
• Eosinophils
• Dendritic cells and lymphocytes

Question 14

Describe how an environmental trigger causes the symptoms of asthma

Answer 14

• Environmental trigger is breathed in and triggers inflammation
• Driven by T helper cells which release cytokines like IL-2
• Causes release of histamine and prostaglandins from mast cells
• These cause bronchoconstriction, inflammation and mucus production

Question 15

Describe the remodelling of the airways that occurs in asthmatics

Answer 15

• Epithelium is stressed and there is loss of cilated columnar cells
• Basement membrane is thickened by collagen
• Smooth muscle undergoes hyperplasia

Question 16

Describe the wheeze heard from asthmatic patients

Answer 16

• high pitched expiratory sound
• originates in narrowed airways by compression/obstruction
• variable intensity and tone

Question 17

Name some of the main symptoms of asthma

Answer 17

• Wheeze
• Cough (worse at night, may be exercise induced)
• Breathlessness
• Chest tightness

Question 18

What tests/imaging techniques are used to confirm or deny asthma?

Answer 18

• Spirometery flow volume loop
• allergy testing
• chest x-rays - to exclude other disease

Question 19

What non-pharmacological treatments may be used in asthma?

Answer 19

• Education to correctly recognise symptoms
• stop smoking
• decease exposure to allergens
• weight loss

Question 20

What is the front line of treatment in mild asthmatics?

Answer 20

• Beta-2 adrenoagonist
• Salbutamol
• short acting