Protein in urine and rhabdomyolysis: what to know

Rhabdomyolysis happens when damaged muscle fibres release substances into the bloodstream. A urine dipstick may detect blood-related pigment even when few or no red blood cells are seen under a microscope. This can be mistaken for blood or described alongside protein in urine. Dark tea-coloured urine, marked muscle tenderness, weakness, swelling, or reduced urination can occur, but symptoms vary.

The released muscle proteins and pigments pass through the kidneys. A clinician may check urine, blood tests, electrolytes, and kidney function to judge the severity and identify triggers such as strenuous exercise, injury, prolonged pressure, medication effects, or heat exposure.

Arrange same-day medical advice if rhabdomyolysis is suspected, especially after unusually intense exercise or an injury. Stop strenuous activity and do not resume training while symptoms are being assessed. Do not self-treat by forcing large amounts of fluid if you have heart or kidney disease; a clinician can advise safe hydration and treatment.

Bring a list of medicines, supplements, recent exertion, injuries, and any change in urine colour or volume. Muscle soreness after exercise can be ordinary, but severe or unusual symptoms need a different assessment.

Go to an emergency service for very dark urine, little or no urine, worsening weakness, severe swelling, confusion, fainting, chest symptoms, or trouble breathing. Seek urgent help after heat exposure or prolonged immobility when muscle pain is intense. Kidney problems and electrolyte disturbances can develop without dramatic pain, so worsening urine output should not wait.

Ask which test showed protein or pigment, whether kidney function and electrolytes are normal, what caused the muscle injury, how much activity and fluid are appropriate, and which warning signs should prompt immediate reassessment.