GEP (Life Protection) Week 5

Question 1

What are the 4 types of chronic inflammation?

Answer 1

1. Non-specific
2. Autoimmune
3. Chronic suppurative
4. Chronic granulomatous

Question 2

Define chronic inflammation?

Answer 2

This is where inflammation persists for weeks, months or longer. It may occur from acute inflammation or from the outset. It is more likely to cause tissue destruction and heal with irreversible scarring rather than regeneration.

3 process occurs simultaneously
-Persistent tissue injury and destruction
-Ongoing inflammatory response to limit the damage
-Attempts to organise and heal by fibrosis (scarring)

Question 3

Describe the different response of the innate and adaptive immune response to inflammation?

Answer 3

Question 4

What is a granuloma?

Answer 4

This is an aggregate of activated (epithelioid) macrophages, which have formed when a causeative agent cannot be removed. This granuloma is formed by a ring of macrophage, TH1 cell and others walling the site of inflammation to stop the spread.

Composition of granuloma:
-Macrophages​
-Lymphocytes: mainly T-cells & some B-cells​
-Fibroblasts, connective tissue (collagen)​
-Necrotic tissue ​

Question 5

How many types of hypersensitivity is there?

Answer 5

There are 5 types of hypersensitivity

Question 6

Describe the different types of hypersensitivity (1,2,3,4)

Answer 6

Question 7

Describe the different types of hypersensitivity (1,2,3,4) continued.

Answer 7

Question 8

Describe type 5 hypersensitivity?

Answer 8

Type 5 hypersensitivity is technically classified as type 2 but given different calssification because of their antigen-mediated stimulatory/inhibitory effect.
Except 2 exceptions:
graves and myasthenia gravis are type 2 hypersensitivity.

Question 9

What is the definition and aetiology of Tuberculosis?

Answer 9

-TB is the infection of mycobacterium tuberculosis.
-It is spread by inhalation of infectious droplets released when coughing
-There needs to be a prolonged contact for transmission.
-Aerobic rod-shaped bacilli, with a high oxygen demand, so usually infect the upper lobes of the lung
-‘Acid fast’ when using the Ziehl-Neelsen stain.

Mycobacteria are called acid-fast bacilli because they are rod-shaped bacteria (bacilli) that can be seen under the microscope following a staining procedure in which the bacteria retain the color of the stain after an acid wash (acid-fast).

Question 10

Brief Epidemiology of TB

Answer 10

-1 of the Top 10 causes of death worldwide
-1.7-2 billion people have latent TB worldwide.
-Significant mortality from co-infection with HIV
-40% of UK cases occur in London.

Question 11

Describe the pathophysiology of TB?

Answer 11

Question 12

What is a ghon focus

Answer 12

It is a small focus of granulomatous inflammation, which may become visible on a chest X-ray if it grows large enough or if it calcifies. A Ghon focus usually heals without further trouble, but in some patients tuberculosis spreads from it via the lymphatics, the air spaces, or the bloodstream.

Question 13

What is a ghon complex

Answer 13

A ghon complex= ghon focus + ipsilateral mediastinal lymph nodes

Question 14

Describe the natural history of TB infection

Answer 14

Question 15

What are the clinical signs and differential for TB

Answer 15

Differentials
-Lung cancer
-COVID
-Pneumonia
-Sarcoidosis
-Lymphoma
-Other!

Question 16

What are the extrapulmonary manifestations?

Answer 16

-CNS - TB meningitis (headache, neck stiffness, vomiting), reduced consciousness, focal neurological signs)
-Lymph node TB - enlarged, firm, non-tender cervical lymph nodes
-Genitourinary TB
-Pericardial TB - pericardial effusion, constrictive pericarditis
-Bone - Pott’s disease, spinal pain, often localised
-GI - mostly affects ileocecal region, causes abdo pain, bloating and obstruction

Question 17

what are the risk factors for TB?

Answer 17

Risk factors
-Close contact with TB patient, increased risk with duration of exposure
-Ethnic minority groups
-Being born in high prevalence areas - India, Pakistan, Romania, Bangladesh, Somalia
-HIV positive
-Other causes of immunocompromise
-Extremes of age
-Homelessness
-Prisoners
-IVDU

Question 18

What are the steps of diagnosing TB?

Answer 18

Question 19

How do you diagnose latent TB?

Answer 19

Latent TB - screening of at risk patients
1) Do a Mantoux test
-Positive - TB specialist to assess for active TB
-Active TB positive - treat
-Active TB negative - consider IGRA, if more evidence of latent infection is needed to decide on treatment
2) Underserved groups (prisoners, substance misusers) offered a single IGRA

• Interferon Gamma Release Assay (IGRA)
  Assays detect the interferon gamma response to TB antigens
  Unaffected by prev BCG

Question 20

What is the management of active TB?

Answer 20

-Use the Mnemonic- RIPE
(4 for 2 months then 2 (RI) for 4 months)
-Also infrom public health.

Question 21

What is the management of latent TB?

Answer 21

Latent TB
-6 months of isoniazid with pyridoxine
Usually chosen if concerned about rifampicin interactions
-3 months of isoniazid (with pyridoxine) and rifampicin
Preferred if the patient is younger than 35 if hepatotoxicity is a concern.

Question 22

What is the management of multidrug resistant TB?

Answer 22

This is a Growing problem
Do NAAT (nucleic acid amplification test) for rifampicin resistance if suspicious
Treatment may last 18- 24m with at least 6 drugs

Question 23

How would you treat TB meningitis?

Answer 23

RIPE 2 months followed by RI for a further 10 months
+ Steroids

Question 24

What is the BCG vaccination?

Answer 24

TB vaccination are live attenuated strain of Mycobacterium Bovis (relative of M. TB that does not cause harm in humans)

Effectiveness:
-Prevents severe and complicated disease but less effective at preventing pulmonary TB
-More effective in children than adults

Question 25

Which Demographic are most at risk?

Answer 25

**Neonates/children** -High risk area in the UK for catching TB (London) -Parent/grandparent born in country with higher risk of catching TB -Lived for >3 months/going to country with higher risk of catching TB -Living with/regular close contact with someone who has/had TB **Adults** -High risk through work: healthcare worker, lab operative, vets & abattoir, work with people at high risk of getting TB (homeless, asylum seekers & refugees, prisoners, drug users) -Staying >3 months in high-risk country -Arriving to UK from high-risk country

Question 26

What is the Mantoux test?

Answer 26

Screening test that detects exposure to previous TB: active, latent, BCG vaccine -> Therefore does not diagnosis TB How it works: Inject patient intradermally with Tuberculoprotein Purified Protein Derivative (PPD) PPD presented to memory T-cells -> cell-mediated response Recruitment of B-cells & inflammation -> erythema & induration -> Type 4 Hypersensitivity reaction Positive: induration>5mm after 72hrs Indications Tested prior to BCG vaccination for: >6 years History of residence/prolonged stay in high risk country Close contact with a person with TB FMHx TB within last 5 years ## Footnote Note: HIV infected/ low CD4+ count patients may have negative Mantoux test despite active TB

Question 27

How to interpret an X-ray

Answer 27

ABCDEFGH is the best Mnemonic: A: Adequacy PIER Airway B: Breathing Zone symmetry Bone & soft tissue C: Circulation & Cardiomediastinal contour D: Diaphragm E: Effusions & Everything else F: Fields, fissures & foreign bodies G: Gastric bubble H: Hila ## Footnote E to H is mostly covered in ABCD

Question 28

CxR anatomy

Answer 28

Question 29

Describe A in the X-ray Mnemonic

Answer 29

**Adequacy** PIER P: Patient details & position - PA (posterior anterior) vs AP (Anterior posterior) PA the preferred modality AP if patient is bed-bound & unable to stand (portable X-ray machine) I: Inspiration: 8-10 posterior ribs visible E: Exposure: Heart, blood vessels, spinal processes & thoracic vertebrae visible R: Rotation: symmetrical & equidistant (from spinous processes) clavicles ## Footnote PA Scapula in periphery of thorax Clavicles project over lung fields Posterior ribs more distinct Low diaphragm Normal cardiac silhouette Narrow superior mediastinum AP Scapula over lung fields Clavicles above apex of lungs More magnified Anterior ribs more distinct Magnification of heart Widening of mediastinum

Question 30

Describe A in the X-ray Mnemonic (continued)

Answer 30

-Check for tracheal deviation (it may sit slighly to the right due to the aortic arch/ascending aorta -If you see a push trachea: this could be a large pleural effusion or tension pneumothorax. -Pulling of the trachea: Consolidation+ lobular collapse.

Question 31

Describe B in the X-ray Mnemonic

Answer 31

**Breathing** Check for symmetry Look for areas of abnormal lucency Masses & nodules Examine lung fields in sequence Fluid/tumours appear bright **Consolidation:** Material filling the alveoli: Pus: pneumonia Water: Pulmonary oedema Blood: Trauma Cells: tumour There are 3 zones, upper, middle and lower (Note: Described as zones not lobes because lobes are superimposed on each other, thus cannot be sure which lobe structure is in).

Question 32

Describe B in the X-ray Mnemonic (continued)

Answer 32

**Bone & soft tissue** Fractures Mineralisation/osteopenia Lucent bone: decreased density (dark) Sclerotic bone: increased density (white) Lesions (metastases)

Question 33

Describe C in the x-ray Mnemonic

Answer 33

**Circulation & Cardiomediastinal contour (&hila) ** Cardiac edges - sharp & pronounced Opacities Silhouette sign Size of heart: less than half of chest width

Question 34

Describe D in the x-ray Mnemonic

Answer 34

**Diaphragm** -Shape Right & left hemidiaphragms: Right usually higher than left due to liver -Sharp costophrenic angles -Gastric bubble Air on right: pneumoperitoneum

Question 35

Describe E in the x-ray Mnemonic

Answer 35

**Effusion and Everything else** Build-up of fluid Everything else: Tubes: NGTs Lines: Central lines, ECGs Pacemakers/ICDs Artificial heart valves

Question 36

Describe F in the X-ray Mnemonic

Answer 36

Fields, Fissures and Foriegn Bodies -Observing the fissures are in the correct location and there are no visible foriegn bodies

Question 37

Describe G in the X-ray Mnemonic

Answer 37

Gastric bubble Normally seen in the left side of an x-ray and is dark, indicating gas

Question 38

Describe H in the x-ray Mnemonic

Answer 38

Hila Lie at same level (left may sometimes lie higher than right) Similar size & density

Question 39

Another way of remembering how to interpret an X-ray

Answer 39

Question 40

What is koch's postulates

Answer 40

**Designed to show causative relationship between microbe & disease - Germ Theory​** -Demonstrate that the organism is in the lesions in all cases of that disease​ -Be able to isolate the organism and cultivate it in pure culture outside the host​ -Produce the same disease if the pure culture is injected into a healthy subject​ -Recover microbe from experimentally infected host​ **However we now know:​** -Not all organisms can be cultured​ -Can detect their DNA/RNA by PCR​ -Not universally applicable to all diseases e.g., cancers associated with viruses (HepB; EBV)​