Pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is defined as pneumonia in individuals who are not in hospital (or who have been in hospital <48 h) and are not immune compromised.

TYPICAL PNEUMONIA

The commonest CAP is with S. pneumoniae (majority) or H. influenzae.

Clinical features

• Rapidly ill with high temperature, rigors, night sweats, dry cough, pleuritic pain

• 1–2 d later may be rusty coloured sputum

• Rapid and shallow breathing follows

• X-ray and examination: consolidation (patchy or lobar)

THE ATYPICAL PNEUMONIAS

Common clinical features

• Fever, malaise (flu-like illness)

• Headache

• Minimal respiratory symptoms, non-productive cough

• Signs of consolidation absent

• Chest X-ray (diffuse infiltration) incompatible with chest signs

Causes

Mycoplasma pneumoniae—the commonest:

• adolescents and young adults

• treat with roxithromycin 300 mg (o) daily or doxycycline 100 mg bd for 14 d

Legionella pneumonia (legionnaire disease):

• related to cooling systems in large buildings

• incubation 2–10 d

Diagnostic criteria include:

• prodromal influenza-like illness

• a dry cough, confusion or diarrhoea

• very high fever (may be relative bradycardia)

• lymphopenia with moderate leucocytosis

• hyponatraemia

Patients can become very prostrate with complications—treat with azithromycin IV (first line) or erythromycin (IV or O) plus (if very severe) ciprofloxacin or rifampicin.

Chlamydia pneumoniae:

• treatment similar to mycoplasma

Chlamydia psittaci (psittacosis):

• treat with doxycycline 200 mg (o) statim then 100 mg/d for 14 d or roxithromycin

Coxiella burnetii (Q fever):

• treat with doxycycline 200 mg (o) statim then 100 mg/d for 14 d

ANTIBIOTIC TREATMENT FOR CAP ACCORDING TO SEVERITY

Mild pneumonia (not requiring hospitalisation)

• Amoxicillin/clavulanate 875/125 mg (o) bd, esp. if S. pneumoniae isolated or suspected plus

• (Esp. if atypical pneumonia suspected), roxithromycin 300 mg (o) daily for 7d

Moderately severe pneumonia (requiring hospitalisation)

• Benzylpenicillin 1.2 g IV 4–6 hrly for 7 d (drug of choice for S. pneumoniae) or procaine penicillin 1.5 g IM/d for 7 d

• Amoxicillin/clavulanate 875 mg bd (if not so severe and oral medication tolerated) or

• Ceftriaxone 1 g IV daily for 7 d (in penicillin-allergic patient) plus

• Doxycycline (dose as above)

Severe pneumonia The criteria for severity are presented in Table P7.