Pneumonia

Question 1

Define pneumonia and its classifications

Answer 1

Infection of the lung parenchyma

Categories:
Community acquired, hospital acquired, nosocomial
Aspiration, immunocompromised
Typical and atypical

Question 2

Causes of community acquired pneumonias (CAP)

Answer 2

Typical - Strep. Pneumoniae (70%), H. influenzae (COPD), S. aureus, Moraxella Catarrhalis (COPD)

Atypical - Mycoplasma pneumoniae, Legionella, Pneumocystis Jirovecii, chlamydia psittaci, chlamydia pneumoniae

Question 3

What the following is associated with: legionella, pneumocystis jirovecii, chlamydia psittaci, mycoplasma, s. aureus

Answer 3

Legionella - water, soil, air conditioning (plumber) -> hyponatraemia, lymphopenia and abnormal LFTs

Pneumocystis Jirovecii (PCP): HIV -> desaturates on exercise

Chlamydia psittaci - pet birds/parrots

Mycoplasma: dry cough, erythema multiforme (target rash with central blister), reticule-modular shadowing of the right lung

S. Aureus: preceding influenza infection predisposes

Question 4

Causes of hospital-acquired pneumonia (HAP)

Answer 4

S. aureus, Pseudomonas aeruginosa, Klebsiella (alcoholics)

Question 5

Causes of aspiration pneumonia and viral pneumonia

Answer 5

Aspiration - anaerobes (from gut flora), klebsiella

Viral - Influenza, RSV

Question 6

Symptoms of pneumonia (typical)

Answer 6

Productive cough (green sputum)
Fever
Dyspnoea
Pleuritic chest pain
Confusion

Question 7

Symptoms of pneumonia (atypical)

Answer 7

Dry cough 
Headache 
Diarrhoea
Myalgia
Hepatitis

Red current jelly sputum - klebsiella
Exercise-induced desaturation - pneumocystis is jirovecci

Question 8

Signs of pneumonia

Answer 8

Resp. distress
Cyanosis
HR and RR raised

Reduced chest expansion
Febrile

Dull percussion

Basal crepitations
Bronchial breathing
Increased vocal resonance/fremitus

Question 9

Investigations for pneumonia

Answer 9

Sputum MCS
Urinalysis (legionella and pneumococcus)

FBC
CRP 
Blood cultures
ABG 
U+Es (hyponatraemia for Legionella)
LFTs (deranged in legionella)
Blood film (Agglutination by cold agglutinins in mycoplasma)

CXR: lobar/patchy shadowing
Pleural fluid MCS
Bronchoscopy + BAL (pneumonia fails to resolve)

Question 10

What is the scoring system used for pneumonia

Answer 10

CURB-65 score 
Confusion (AMTS <8)
Urea >7
RR >30 
BP <90/60
Age >65 

CURB 0 or 1 - Amoxicillin oral 500mg, home based care
CURB 2 - Hospital based care
CURB 3 - Intensive care

Question 11

Acute management of pneumonia generally

Answer 11

1. ABCDE
2. Oxygen and sit up
3. IV fluids
4. IV painkillers
5. IV antibiotics

Question 12

Which antibiotics are used for the following pneumonias (CAP, atypical, unknown cause, HAP (staph, MRSA, pseudomonas), aspiration, pneumocystis jiroveci)

Answer 12

CAP - amoxicillin, co-amoxiclav if severe
Atypical - Clarithromycin
Unknown cause: Amoxicillin + clarithromycin

Staph - Flucloxacillin
MRSA - Vancomycin
Aspiration - tazocin + gentamicin

Aspiration - metronidazole

Pneumocystis: co-trimaxazole

Question 13

Supportive management of pneumonia

Answer 13

Oxygen
Parenteral fluids for dehydration or shock
Analgesia, chest physiotherapy
CPAP, BiPAP or ITU for resp. failure
Consider surgical drainage for empyema/abscess
Offer pneumococcal, H. influenzae type B vaccination

Question 14

Complications of pneumonia

Answer 14

Pleural effusion
Lung abscess (often S. aureus) -> swinging fevers, persistent pneumonia, foul smelling sputum)
Empyema 
Septic shock 
ARDS
Acute renal failure

Question 15

Complications of M. pneumoniae

Answer 15

Erythema multiform
Myocarditis
Haemolytic anaemia
Meningoencephalitis
Transverse myelitis, GBS