Tuesday, 21 September 2010

MRCP revision battle 17.4: Legionella

Legionella is a gram negative bacteria which causes legionella disease/pneumonia and in MRCP questions is most likely found living in a cruise ship/hotel's water tank or airconditioning system.

The symptoms of legionella disease are:
  • flu-like
  • dry cough
  • dypnoea
  • GI upset

Complications of legionella which may show up in the blood results include:
  • SIADH - low sodium
  • hepatitis - deranged LFTs

Legionella is killed above 60c, cannot multiply between 50 and 60c and are happiest between roughly 35 to 45 c

Males are more affected than females, 3:1

CXR may show bibasal consolidation.

Treatment is with antibiotics which achieve a high intracellular concentration, such as clarithromycin, rifampicin or fluroquinolone.

Legionella has a 10% mortality.

Lets now trot on to pleural calcification...