Tasty Morsels of EM 137 – Influenza in kids

22 Jan

This batch of the tasty morsels series are various pearls and learning points from my most recent 6 months doing paeds EM. I’d done a fair bit of paeds before but never in a dedicated children’s hospital and it was all a long time ago. Turns out there’s always more to learn. These are mainly observations and anecdotes even more so than usual!

Influenza myositis

  • this is surprisingly really common. We knew flu season had started cause we had 3 of these in a day. Somewhere in the back of my head I knew this was a thing but didn’t realise quite how common it was.
  • We’re so used to limping children having simple transient synovitis that seeing a febrile child crawling with pain in both legs is a bit of a shock to start with.
  • It is probably more influenza B than A
  • It’s usually in the calves where there’s usually obvious tenderness and sometimes swelling.
  • CK is unsurprisingly raised but rhabdo does not seem to be a concern.
  • A rapid flu test (which we have) provides some diagnostic satisfaction for all but may not be needed at all.  Rapid flu tests have a tendency to be quite specific (so if it’s positive it’s really positive) but not particularly sensitive (so it’ll be negative in a fair number who actually have flu)


  • Magee H, Goldman RD. Viral myositis in children. Can Fam Physician. 2017;63(5):365-368. [Free full text]

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