SPUR Infections

I mentioned SPUR infections yesterday: why are they important and how do you know what you're looking at falls into this category?

SPUR is an acronym standing for:

• Serious
• Persistent
• Unusual or
• Recurrent

Serious infections are those which are potentially life-threatening. You could include in that, for example, pneumonia and meningitis, all of which are always serious. More indicative, however, is when what is normally a mild infection, such as tonsilitis, becomes serious, such as quinsy (aka. peritonsillar abscess).

Persistent infections are those which don't clear up when appropriately treated. So, for example, tonsilitis which isn't responding to amoxycillin.

Unusual infections are those which wouldn't normally arise in that population. For example, Kaposi's sarcoma and Pneumocystis carinii pneumonia don't arise in people with functioning immune systems, and presence of these should suggest that immune problems should be investigated.

Recurrent infections are those which appear to be resolved, but which come back time and time again. This is normally because the bacterial population has dropped below the pathological threshold (most bacteria only cause disease when there are more than a given number of them). In a person who is immunocompetent, those bacteria would be tagged by immunoglobulins and then destroyed by macrophages. In people with immune problems, they regroup and start recolonising, causing the infection to flare back up.

SPUR infections are important because they suggest that something abnormal is happening which needs to be investigated. Typically it will be something inoccuous or just "bad luck", but once in a while someone with SPUR infections will turn out to have a PID...