Which musculoskeletal complication can occur with influenza, especially in children?

• A. Osteoporosis
• B. Fibromyalgia
• C. Acute myositis and rhabdomyolysis
• D. Tendinitis

Answer: (C)

Influenza in children can trigger muscle inflammation as a direct or indirect effect of the infection, leading to acute musculoskeletal problems. The best example is acute myositis, which can occur after a flu illness and cause sudden calf or thigh pain with a child being reluctant or unable to walk. In some cases, this muscle breakdown is more extensive, known as rhabdomyolysis, which may show elevated muscle enzymes and urine myoglobin. Most kids recover quickly with rest and fluids, though monitoring for dehydration or signs of kidney involvement is important because rhabdomyolysis can raise that risk.

Osteoporosis is a chronic bone-thinning condition and isn’t an acute influenza-related complication. Fibromyalgia is a chronic pain syndrome, not an infection-linked, transient complication of the flu. Tendinitis can occur in general but isn’t a characteristic influenza-related issue in children. The combination of sudden muscle pain and possible inability to walk after a flu makes acute myositis (with or without rhabdomyolysis) the strongest, most specific musculoskeletal complication linked to influenza in kids.