Rhabdomyolysis: This is the most direct diagnosis given the context of the question, which directly mentions "rhabdo." Rhabdomyolysis is a serious syndrome due to direct or indirect muscle injury. It results from the death of muscle fibers and the release of their contents into the bloodstream, leading to complications such as renal failure. This condition can be caused by various factors including intense physical activity, trauma, certain medications, drug abuse, or infections.

Severe muscle strain or injury: This could be considered if the context implies recent physical exertion or trauma without clear evidence of muscle cell death.
Muscle dystrophies: Though less likely in an acute presentation, certain muscular dystrophies could lead to significant muscle damage and potentially mimic some symptoms of rhabdomyolysis.
Polymyositis/Dermatomyositis: These are inflammatory muscle diseases that could present with muscle weakness and elevated muscle enzymes, though they typically have a more subacute or chronic presentation.

Acute kidney injury: Not a diagnosis in itself but a critical complication of rhabdomyolysis. Early recognition and management are crucial to prevent long-term renal damage.
Compartment syndrome: A condition resulting from increased pressure within a muscle compartment, which can lead to muscle and nerve damage. It is a medical emergency and can cause rhabdomyolysis if not promptly treated.
Neuroleptic malignant syndrome (NMS): A life-threatening neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic medication. It can present with muscle rigidity, fever, and altered mental status, which might be confused with rhabdomyolysis in some cases.

Malignant hyperthermia: A rare but life-threatening medical emergency triggered by exposure to certain drugs used for general anesthesia, particularly volatile anesthetic gases and the depolarizing muscle relaxant succinylcholine. It can cause a very high fever and muscle rigidity, among other symptoms.
Statin-induced myopathy: While statins are known to cause muscle pain and elevated liver enzymes, severe rhabdomyolysis is a rare but recognized side effect, especially with high doses or in combination with other drugs.
Infectious myositis: Certain infections, such as bacterial, viral, or parasitic, can cause muscle inflammation and damage. These are less common causes of significant muscle injury but should be considered, especially in immunocompromised patients or those with specific exposures.