pneumonia

Question 1

what is it?

Answer 1

Pneumonia is an inflammatory condition of the lung parenchyma caused by infection. Alveoli become filled with inflammatory cells and microorganisms, leading to consolidation of the lung tissue. This impairs gas exchange and can lead to hypoxia.

Question 2

what is the aetiology?

Answer 2

commonest cause of pneumonia is Streptococcus pneumonia, which is usually community-acquired, followed by Haemophilus influenzae and Moraxella catarrhalis. These are referred to as typical pneumonias

Atypical pneumonias have a variety of atypical features, e.g. a more insidious onset, extra-pulmonary symptoms such as headache and varying appearances on chest imaging. These include Mycoplasma pneumoniae, Legionella pneumophila and Chylmydophila psittaci.

Hospital-acquired pneumonias are defined as pneumonia that started 48 hours or longer after admission. Gram negative organisms such as Pseudomonas aeruginosa, as well as Staphylococcus aureus are more common in these environments.

Question 3

descrie staphylococcal pneumonia

Answer 3

A bilateral cavitating bronchopneumonia due to staphylococcal aureus, a gram-positive cocci found in clusters.
Commoner in intravenous drug users, elderly patients, or as a superadded bacterial infection in those with influenza.

Question 4

describe klebsiella pneumonia

Answer 4

Usually a cavitating pneumonia affecting the upper lobes presenting with red-currant sputum.
It is caused by a gram-negative anaerobic rod.
Increased risk in the immunocompromised, elderly and in alcohol excess.

Question 5

describe mycoplasma pneumonia

Answer 5

Presents with flu-like symptoms of arthralgia, myalgia, dry cough and headache.
Primarily affects younger patients.
Associated with an autoimmune haemolytic anaemia caused by cold agglutinins.
May lead to erythema multiforme, Stevens-Johnson syndrome, Guillain-Barre syndrome and meningoencephalitis.

Question 6

describe legionella pneumonia

Answer 6

Fever, myalgia and malaise followed by dyspnoea and a dry cough are typical presenting features.
Caused by a gram-negative coccobacillus.
Occurs in those exposed to contaminated water e.g. in humidifiers or cooling systems.
Typically causes hyponatraemia and deranged liver function tests.

Question 7

describe Chlamydophila psittaci pneumonia

Answer 7

An intracellular bacteria acquired from contact with infected birds such as parrots.
Features include lethargy, arthralgia, headache, anorexia, dry cough and fever.

Question 8

what is CURB criteria?

Answer 8

Confusion
Urea > 7mmol/L
Respiratory rate > 30 breaths/min
Blood pressure < 90 systolic and/or < 60mmHg diastolic
65 years or older

Question 9

how is CURB used for tx?

Answer 9

A CURB-65 score of 0-1 requires home treatment, 2 should consider hospital admission, 3-5 admit to hospital and consider ITU referral.

Question 10

features of pneumonia?

Answer 10

Fever
Malaise
Rigors
Cough
Purulent sputum
Pleuritic chest pain
Haemoptysis

Tachypnoea
Tachycardia
Hypotension
Cyanosis
Pyrexia
Dullness to percussion over the consolidated area
Increased vocal resonance/ tactile vocal fremitus over the consolidated area
Bronchial breathing over the consolidated area
Pleural rub may be heard due to inflammation of the adjacent pleura

Question 11

what are bedside tests?

Answer 11

Sputum for microscopy, culture and sensitivity
Consider arterial blood gas if hypoxaemic
Urinary legionella and pneumococcal antigens
ECG to look for complications e.g. atrial fibrillation

Question 12

what bloods does?

Answer 12

Blood cultures if febrile
FBC and CRP for inflammatory markers
U&Es to look for an AKI
LFTs may be deranged e.g. in Legionella, baseline important when giving antibiotics
Mycoplasma serology if atypical pneumonia suspected
HIV testing should be offered to all patients with recurrent pneumonia (and all patients in a high prevalence area such as London)

Question 13

what imaging done?

Answer 13

Chest X-ray: may show lobar consolidation or bilateral consolidation in atypical infections, parapneumonic effusions may also be seen.
CT chest may be indicated in some cases (e.g. suspected underlying malignancy, suspicious findings on X-ray)

Question 14

what does this show?

Answer 14

R sided basal pneumonia

Question 15

what is conservative mx?

Answer 15

Oxygen if low saturations
IV fluids if dehydrated
Analgesia for myalgia or chest pain
Escalate for respiratory support (e.g. continuous positive airway pressure or intubation and ventilation) if patients are severely unwell - consider escalation status and patient wishes

Question 16

what is medical mx?

Answer 16

Oral antibiotics for patients managed in the community (e.g. amoxicillin 500mg three times a day for 5 days)
IV antibiotics for those admitted with more severe pneumonia (e.g. co-amoxiclav and clarithromycin)

Question 17

what is pneumonia follow up?

Answer 17

Patients with pneumonia should be followed up with a repeat chest X-ray after 6 to 8 weeks to screen for an underlying lung cancer (as this may be masked on initial imaging by infective changes).

Question 18

what are complications?

Answer 18

Parapneumonic effusion
Empyema
Lung abscess
Sepsis