Infection

Question 1

Management of pneumonia

Answer 1

Assess using ABC
Treat hypotension/shock from infection
Assess for dehydration (common if acutely unwell and fever) - consider IV fluid support
Investigations to assess severity
Antibiotics
Analgesia for pleuritic chest pain e.g. paracetamol 1g/6h or NSAID

If no improvement e.g. hypoxic despite oxygen then consider CPAP to recruit lung parenchyma and improve oxygenation. But if patient is hypercapnic, they will require ventilation. If no changes in PaCO2 or hypoxia, refer to ICU

Question 2

Investigations for severity of pneumonia (management of pneumonia)

Answer 2

CXR
Oxygen saturation and ABG if SaO2 <92% or severe pneumonia
FBC, U and E, LFT, CRP
Blood cultures (CURB-65 criteria at least 2)
Sputum cultures (CURB-65 criteria at least 3 or if 2 and not had antibiotics)
Urine pneumococcoal antigen (CURB-65 criteria at least 2) or Legionella antigen (CURB-65 criteria at least 3)
Viral throat swabs (consider) and mycoplasma serology
Pleural fluid aspirated for culture (CURB-65 criteria at least 2)
IF immunocompromised or on ICU, consider bronchoscopy or bronchoalveolar lavage

Question 3

Describe each part of CURB-65 score

Answer 3

Confusion (abbreviated mental test less than 9)
Urea >7mmol/L
Respiratory rate (at least 30/min)
Blood pressure (<90/60mmHg)

Age (at least 65)

Question 4

Indications depending on CURB-65 score

Answer 4

0-1: home treatment if possible
At least 2: hospital therapy
At least 3: indicates severe pneumonia and should consider ICU referral

Question 5

What is pneumonia

Answer 5

Infection of lung parenchyma caused by a lower respiratory tract infection

Question 6

Epidemiology of pneumonia

Answer 6

Community-acquired pneumonia is 5-11 per 1000 adults

Of these 1-3 per 1000 will require hospitalisation and mortality is those hospitalised is up to 14%

Question 7

Most common organism causing pneumonia

Answer 7

Streptococcus pneumoniae (60-75%)

Question 8

Organisms that can cause pneumonia

Answer 8

Streptococcus pneumoniae
Haemophilus influenzae
Mycoplasma pneumoniae
Staphylococcus aureus (found more commonly in ICU patients)
Legionella species and Chlamydia psittaci
Gram-negative bacilli, often hospital-acquired or immunocomprimised e.g. Pseudomonas (especially those with COPD)
Viruses

Question 9

What % of pneumonia cases are caused by viral infections (including influenza)

Answer 9

15%

Question 10

Symptoms of pneumonia (name 4)

Answer 10

*Fever
Rigors
Malaise
Anorexia
*Dyspnoea
*Cough with purulent sputum (classically rusty with pneumococcus)
Haemoptysis
*Pleuritic chest pain

Question 11

Signs of pneumonia (name 4)

Answer 11

*Percussion - dull
*Auscultation - crackles, bronchial breathing
*Septicaemia - Rigors
*Respiratory failure - Cyanosis, Tachypnoea
Herpes labialis (pneumococcus)
Confusion
Tachycardia
Hypotension
Signs of consolidation (diminished expansion, increased vocal resonance)
Pleural rub

Question 12

Complications of pneumonia

Answer 12

Pleural effusion
Empyema
Lung abscess
Respiratory failure
Septicaemia
Pericarditis
Myocarditis
Cholestatic jaundice
AKI

Question 13

What is an acute ooryza

Answer 13

Permenant dilation and thickening of the airways

Question 14

Aetiology of acute ooryza

Answer 14

Infection by rhinovirus: spread by droplets and close personal contact

Question 15

Pathophysiology of acute ooryza

Answer 15

Virus binds to ICAM-1 receptors -> releases inflammatory mediators by unknown mechanism

Question 16

Epidemiology of acute ooryza

Answer 16

Extremely prevalent.

Multiple regional strains.

Question 17

Clinical presentation of acute ooryza

Answer 17

Incubation period of 12hrs - 5 days.

Then, malaise, mild pyrexia, sore throat and watery nasal discharge.

Question 18

Treatment of acute ooryza

Answer 18

Symptomatic.

Nasal decongestants, ibuprofen for malaise.

Question 19

Epidemiology of TB

Answer 19

9. 6 mil new cases/yr (37% unexpected/undiagnosed)
10. 3% and 20% of previously treated are drug resistant
11. 5 million deaths/yr

Question 20

What % of TB cases have a co-infection with HIV

Answer 20

12%

Question 21

True or False:

Leading cause of death worldwide (1.5 million/year)

Answer 21

True

Question 22

Epidemiology of TB specific to UK

Answer 22

~8000/year or 12 per 100000
73% born outside UK
70% in deprived areas
30% with pulmonary disease (wait>4months from symptoms to treatment)

Question 23

What bacteria causes TB

Answer 23

Mycobacterium tuberculosis

Question 24

Pathophysiology of acute TB infection

Answer 24

Occurs when containment by immune system (macrophages and T-cells) is inadequate.
Can arise from primary infection or re-activation of previously latent disease.

Question 25

How is TB transmitted

Answer 25

Via inhalation of aerosol droplets containing bacterium. | Means only pulmonary disease is communicable.

Question 26

Pathophysiology of latent TB infection

Answer 26

Infection without disease due to persistent immune system containment (i.e. granuloma formation prevents bacteria growth and spread). Positive skin/blood testing shows evidence of infection but patient is asymptomatic and non-infectious.

Question 27

Risk factors of re-activation by TB or latent TB

Answer 27

``` New infection (<2 years) HIV Organ transplantation Immunosuppression (includes corticosteroids) Silicosis Illicit drug use Malnurition High-risk settings (homeless shelter, prison) Low socio-economic status Haemodialysis ```

Question 28

Most common site in body of TB disease

Answer 28

Lungs (pulmonary) - 52%

Question 29

Other sites (not lungs) in body of TB infection

Answer 29

``` Extra-thoracic lymph nodes (24%) Intra-thoracic lymph nodes (12%) Pleural (9%) Gastrointestinal (6%) Spine, Other bone, Miliary, Meningitis, GU ```

Question 30

Treatment of pneumonia

Answer 30

``` BAPP Breathing: Maintain oxygen saturation levels Antibiotics: treat underlying cause Pain = give analgesics Pneumococcal vaccines for those at risk ```

Question 31

Possible methods of invasion in pneumonia

Answer 31

Inhibition of IgA Pneumolysins - inhibit ciliary beating Damage of epithelial cells by prior infection Use of platelet aggregating factor receptor pathway to reach the alveoli

Question 32

People at higher risk of pneumonia and thus get a pneumococcal vaccine

Answer 32

Diabetics Immunosuppressed >65 years old

Question 33

Complications of pneumonia

Answer 33

``` Respiratory failure (due to ARDS) Septic shock (release of cytokines in blood) Pleural effusion Empyema Lung abscess Hypotension ```

Question 34

Cause of respiratory failure from pneumonia

Answer 34

Acute Respiratory Distress Syndrome

Question 35

Cause of hypotension from pneumonia

Answer 35

Dehydration | Sepsis

Question 36

Ix of pneumonia

Answer 36

CXR (shows infiltrates) Sputum sample analysis (causative organism) Monitor oxygen sats Bloods - Raised WCC and inflammatory markers Urinary antigen test - pneumococcal or Legionella antigen Arterial blood gas (ABG)