DR Medhat MRCP

Legionella pneumonia
- Legionnaire's disease is caused by the intracellular bacterium Legionella pneumophilia.
- It is typically colonizes water tanks and hence questions may hint at air conditioning
(AC) systems or foreign holidays.
- Person-to-person transmission is not seen
Features
Flu-like symptoms
Dry cough
Relative bradycardia
Confusion
Lymphopenia
Hyponatraemia
Deranged LFTs
Legionella is suggested if 3 of the following 4
features are present:
1. Prodormal viral like illness
2. Dry cough, confusion or diarrhea
3. Lymphopenia without marked
leucocytosis.
4. Hyponatremia
Diagnosis
Urinary Legionella antigen
Management
Erythromycin
Pneumocystis carnii (jiroveci) pneumonia
- Whilst the organism Pneumocystis carinii is now referred to as Pneumocystis jiroveci,
the term Pneumocystis carinii pneumonia (PCP) is still in common use
- Pneumocystis jiroveci is an unicellular eukaryote, generally classified as a fungus but
some authorities consider it a protozoa
- PCP is the most common opportunistic infection in AIDS , alcoholics & drug abusers
- All patients with a CD4 count < 200/mm³ should receive PCP prophylaxis.
Features
1. Dyspnoea
2. Dry cough (for several weeks)
Typically : desaturation on exertion
3. Fever
4. Very few chest signs (↑RR ,↑HR ,fine crackles) Hepatosplenomegaly.
5. Extrapulmonary manifestations are rare (1-2% of cases) Lymphadenopathy
Choroid lesions.