Thus begins the PEMBlog series on Osteomyelitis. In each edition I’ll tackle a different question – ranging from diagnosis to therapy and hopefully review most of the finer points. There is no better place to begin than at the start. Osteo as it will now be known (because I don’t feel like typing the myelitis part) is a bacterial infection of the bone. It gets there in 3 ways – see if you can guess them:
In the US and other high-income countries the incidence is approximately 8/100,000 – though this number is higher in other parts of the world. The Male:Female ratio skews towards those with Y chromosomes to the tune of 2:1. The number one offender is Staphylococcus aureus followed by S. pyogenes and S. pneumoniae. But the 2 latter are jealous of Staph’s bone infecting skills. MRSA osteo cases generally present with higher fever , more tachycardia and more pain when walking than MSSA. You’ll want to think about Salmonella in patients with sickle cell, and be aware (very aware) that Kingella kingae is on the rise in kids under 4. Read more about that one in a recent report by Yagupsky et al.
Acute osteo means that the kid has been ill for less than 2 weeks, chronic is longer than 3 months subacute can’t decide what it wants to be and occurs in children with osteo between 2 weeks and 3 months. Osteo can occur anywhere in the body, and cases in multiple sites are more common in babies. Check out the excellent diagram at the end of this post from a recent article from the NEJM. Certainly the symptoms vary depending on location – but as redness and swelling sets up along a bone children will experience pain (naturally) as well as reduced function. Since the predominant location in in the long bones, especially the lower extremities this manifests as limp. Regardless of location you should worry about osteo in any child that presents with fever of unknown origin.
You’re now wondering how we should approach diagnosis – for that you’ll have to wait until Part 2… See you then.
from Peltola et al. NEJM, 2014
