Rhabdomyolysis in children: what parents should know

When muscle cells are injured, substances from inside them enter the bloodstream. The kidneys must filter these substances, so significant muscle injury can disturb kidney function and the body's fluid and mineral balance. Triggers may include strenuous exercise, a fall or crush injury, prolonged muscle pressure, infection, heat exposure, or some medicines. A child may describe muscle pain, tenderness, swelling, cramps, or unusual tiredness, but symptoms can be subtle. Urine may become tea-coloured or brown, although its colour can look normal.

This is different from ordinary post-exercise soreness, which usually settles with rest and does not cause profound weakness or urine changes. [Muscle Soreness After Exercise](/symptoms/muscle-soreness-after-exercise/)

Stop strenuous activity and keep the child supervised. Do not give leftover medicines or supplements to treat the problem. Offer fluids only if the child is alert, able to swallow, and a clinician has not restricted fluids; do not force drinking when vomiting or drowsiness is present. Contact a healthcare service promptly and describe the activity, illness, injury, medicines, urine changes, and timing. Assessment may include blood and urine tests, monitoring of urine output, and treatment with fluids or other care based on the findings.

Go to an emergency service immediately for brown or cola-coloured urine, very little or no urine, worsening muscle swelling, severe pain, fainting, confusion, breathing difficulty, repeated vomiting, or unusual difficulty waking the child. Seek urgent advice after intense exercise or an injury when weakness is out of proportion to expected soreness. A child who seems better can still need testing because kidney and mineral changes may not be obvious at home.

Ask which tests are needed, whether the child should pause sports, how much fluid is appropriate, which medicines to avoid, and what urine or activity changes should trigger reassessment. Ask when follow-up blood tests are expected and whether a future episode should prompt evaluation for an underlying muscle or metabolic condition.