resp - toby and louis

Question 1

Which property of mycobacterium tuberculosis makes it resistant to normal staining? Therefore, what are TB bacteria generally described as?

Answer 1

Acid-fastness (due to waxy coating)
Acid-fast bacilli

Question 2

Which stain is therefore used to detect TB bacteria and what colour would the bacteria turn? Which medium is used for culture?

Answer 2

Zeihl-Neelsen staining
Would turn red
Löwenstein- Jensen medium

Question 3

2 groups in which TB is more prevalent?

Answer 3

South Asian people and immunocompromised, e.g. HIV

Question 4

Granulomas form around the body in a TB infection. Caseous necrosis then occurs to the tissue inside the granuloma. In primary TB, what are these known as in the lung?

Answer 4

Ghon focus

Question 5

A primary Ghon focus and associated lymph node involvement make up which radiological finding?

Answer 5

Ghon complex (CXR)

Question 6

Can you name 4 different types/stages of TB?

Answer 6

Active = active infection within various areas of body
Latent = progression of disease stopped
Secondary = when latent TB reactivates (5-10%)
Miliary = uncontrolled spread of disease (disseminated)

Question 7

The most common site for TB infections is in the lung as the bacteria have high oxygen demands. Can you name some pulmonary TB symptoms?

Answer 7

Cough (dry -> productive, 2-3 weeks)
Haemoptysis
Dyspnoea
PLeuritic chest pain

Question 8

How about systemic symptoms? [TB]

Answer 8

Lethargy
Weight loss
Fever
Night sweats
Anorexia

Question 8

How about systemic symptoms? [TB]

Answer 8

Lethargy
Weight loss
Fever
Night sweats
Anorexia

Question 9

What is it and what is it caused by? [TB]

Answer 9

Infectious disease caused by mycobacterium tuberculosis

Question 10

How about some extra pulmonary symptoms of TB?

Answer 10

Erythema nodosum (cutaneous TB)
Spinal pain (a.k.a. Pott’s disease of spine) (spinal TB)
Lymphadenopathy
Abdominal pain (GI system)

Question 11

Can you name 6 different investigation for suspected TB (excluding testing for immune response, i.e. latent TB)?

Answer 11

1st line = CXR
Sputum culture = while on treatment, the patient should have sputum cultures performed at least monthly until two consecutive cultures are negative
Sputum smear = +ve for AFB
NAAT = positive for M. tuberculosis
FBC = WBC increased
Biopsy (e.g. lymph node) = caveating granuloma

Question 12

What are the two investigations for testing to see if there has been an immune response to TB?

Answer 12

Mantoux test (tuberculin (collection of tuberculosis proteins) injected into skin, >5mm induration is positive) and interferon-gamma release assays (IGRAs, sample of blood mixed with antigens from TB bacteria + interferon-gamma released)

Question 13

Can you name 2 CXR findings that may be present in TB? How about miliary TB?

Answer 13

Fibronodular opacities in upper lobe
+/- consolidation
Miliary = millet seeds

Question 14

What are the four antibiotics that can be used to treat acute pulmonary TB?

Answer 14

RIPE:
- Rifampicin
- Isoniazid
- Pyrazinamide
- Ethambutol

Question 15

How about the treatment for latent TB?

Answer 15

Otherwise healthy patients don’t need treatment, but those at risk of reactivation can either have isoniazid and rifampicin for 3 months or rifampicin for 6 months

Question 16

What are the side effects of the RIPE antibiotics?

Answer 16

Rifampicin = red/orange urine/tears
Isoniazid = peripheral neuropathy, i.e. tingling/numbness
Pyrazinamide = gout
Ethambutol = optic neuritis (colour blindness, reduced visual acuity)

Question 17

A patient is started on RIPE for acute pulmonary tuberculosis. What should also be prescribed? Why?

Answer 17

Pyridoxine (vitamin B6)
This is because isoniazid has a side effect of peripheral neuropathy

Question 18

TB is a notifiable disease. Which body does this mean needs to be informed?

Answer 18

Public Health England (PHE)

Question 19

Which vaccine offers protection against severe and complicated TB (but not always pulmonary TB)? Give 2 examples of groups that may be offered it.

Answer 19

BCG vaccine:
- Neonates born in areas of the UK with high rates of TB
- Neonates with relatives from countries with a high rate of TB
- Neonates with a family history of TB
- Unvaccinated older children and young adults (< 35) who have close contacts with TB
- Unvaccinated children or young adults that recently arrived from a country with a high rate of TB
- Healthcare workers

Question 20

What type of hypersensitivity reaction does a TB infection cause?

Answer 20

Type IV hypersensitivity

Question 21

What is it and what is its inheritance pattern? [CF]

Answer 21

Autosomal recessive condition affecting the mucus glands

Question 22

What is it caused by? [CF]

Answer 22

It is caused by a genetic mutation of the CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATORY (CFTR) GENE on chromosome 7

Question 23

What is the most common mutation that causes this? [CF]

Answer 23

Delta-F508 mutation

Question 24

General pathophysiology (helps with understanding)? [CF]

Answer 24

CFTR gene codes for CFTR protein, a CL- channel present in numerous epithelial tissues -> Cl- cannot be transported into lumen + therefore water does not move out by osmosis, making the mucus thick + sticky -> Na+ also moves into cell via electrochemical gradient = makes mucus more thick + sticky

Question 24

General pathophysiology (helps with understanding)? [CF]

Answer 24

CFTR gene codes for CFTR protein, a CL- channel present in numerous epithelial tissues -> Cl- cannot be transported into lumen + therefore water does not move out by osmosis, making the mucus thick + sticky -> Na+ also moves into cell via electrochemical gradient = makes mucus more thick + sticky

Question 25

Both parents are healthy, one sibling has cystic fibrosis and a second child does not have the disease, what is the likelihood of the second child being a carrier of cystic fibrosis?

Answer 25

2/3 - we know that the child doesn't have the condition (both parents must be carriers, however, as AR - 2 carrier parents have a 25% of CF baby)

Question 26

Why is CF a multi system disease?

Answer 26

Affects all duct that produce mucus e.g. airway, pancreas, reproductive tract

Question 27

What are the three key consequences of cystic fibrosis?

Answer 27

THICK PANCREATIC AND BILIARY SECRETIONS - cause blockage of the ducts, resulting in a lack of digestive enzymes, e.g. pancreatic lipase THICK AIRWAY SECRETIONS - reduce airway clearance = bacterial colonisation + susceptibility to airway infections CONGENITAL BILATERAL ABSENCE OF THE VAS DEFERENS in males. Healthy sperm but no way of getting from testes to the ejaculate -> male infertility

Question 28

Which investigation typically diagnoses most cystic fibrosis cases?

Answer 28

NEWBORN BLOODSPOT TEST (Guthrie test) - CF is screened for at birth

Question 29

What is often the first sign of cystic fibrosis?

Answer 29

MECONIUM ILEUS (20%) - first stool (always black) is thick + sticky, causing it to get stuck and obstruct the bowel - presents as not passing meconium within 24 hours, abdominal distension + vomiting

Question 30

If not diagnosed at birther, how does cystic fibrosis present later on in childhood?

Answer 30

- RECURRENT LOWER RESPIRATORY TRACT INFECTIONS - FAILURE TO THRIVE - PANCREATITIS - Chronic cough + thick sputum production - Steatorrhoea (loose, greasy stool due to lack of lipase) - Rectal prolapse - Clubbing - 'SALTY' to kiss -concentrated salt in sweat

Question 31

Three complications of cystic fibrosis in adulthood?

Answer 31

Diabetes mellitus Infertility (males) Pancreatic insufficiency

Question 32

Cystic fibrosis patients struggle to clear their airway, creating a perfect environment for bacteria to grow. What are the two most common types of infection that cystic fibrosis patients are susceptible to?

Answer 32

Staphylococcus aureus and pseudomonas aeruginosa (also haemophilia influenza, klebsiella pneumoniae etc.)

Question 33

What are the four key methods for establishing a diagnosis of cystic fibrosis?

Answer 33

NEWBORN BLOOD SPOT TESTING GOLD STANDARD = SWEAT TEST - Na + Cl >60mmol/L GENETIC TESTING for CFTR gene can be performed during pregnancy by amniocentesis or CVS Faecal elastase - low due to pancreatic insufficiency

Question 34

Can you name 3 ways in which cystic fibrosis can be managed non-pharmacologically?

Answer 34

Chest physiotherapy several times a day is essential to clear mucus and reduce the risk of infection and colonisation Exercise improves respiratory function and reserve, and helps clear sputum High calorie diet is required for malabsorption, increased respiratory effort, coughing, infections and physiotherapy

Question 35

Can you name some ways in which cystic fibrosis can be managed pharmacologically?

Answer 35

Prophylactic antibiotics - flucloxacillin for staph. aureus, amoxicillin for haemophilus influenza Nebulised DNase (dornase alfa) - clears airway of mucus CREON tablets - pancreatic enzyme replacement Bronchodilators, e.g. salbutamol to treat bronchoconstriction Fat-soluble vitamin supplements (A, D, E, K) Nebulised hypertonic saline