It used to be the case that formulating a differential diagnosis (possible causes for what might be wrong with a patient) and implementing a plan of how the differential diagnosis was going to be investigated, was one of the key arts of being a doctor. Many people often make the mistake of thinking the role of a doctor is to write prescriptions but in fact the key role is to work our what is wrong with the patient and then set in motion a plan to make them better if possible.

My cat’s face exploded! Okay, that is not a human problem and a little melodramatic however since this was an abscess secondary to a bite from another cat it does give me chance to talk about cat bites and their complications.

A while ago, I came across a joint fluid result whilst I was reviewing results to be released to the ward doctors. The
patient was in her mid 80s, and her joint fluid contained a small Gram-negative bacillus. The organism was identified as a Pasteurella multocida however, the unusual piece of the story was that this fluid was from her wrist, a very
uncommon place to get a septic arthritis.

At the beginning of a recent medical student teaching session I was asked by a student why he should bother learning normal flora because what he really needed
to know was what causes infections. This is a particularly common and understandable approach from students but misses the significance of the most fundamental principle of microbiology or in fact medicine. If you do not know what is normal, how do you recognise abnormal? I smile inwardly and count to ten before going on to explain the importance of this often overlooked bit of knowledge.