Muscle weakness and Myoglobinuria

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Differential Diagnosis of Muscle weakness and Myoglobinuria

Organ system	Disease	Symptoms												History	Physical Examination	Diagnosis
		Age of onset	Muscle weakness	Fever	Myalgia	Contractures	Gait abnormality	Neuropathy	Atrophy	Stiffness	Myoglobinuria	Other features	Laboratory Findings			Creatine Kinase	Muscle Biopsy	Electromyogram
Medication−induced	Statins	60+	Proximal	−	+	−	−	−	−	−	−/+(Rhabdomyolysis)	N/A	Positive h/o medications H/o other medication use	Tenderness Muscle aches	↑↑ Liver enzymes	↑↑	Necrosis Degeneration, and regeneration of fibers Phagocytic infiltration	Normal
Endocrine	Hyperaldosteronism with myopathy	50	Proximal & distal	−	−	−	−	−	−	−	+ Rhabdomyolysis	Palpitations Hypertension	Episodes of increased heart beats	Hyperpigmentation	Hypokalemia	Normal	Normal	Normal
	Hyperthyroidism	40	Proximal	−	−	−	−	−	+	+	+	Signs of hyperthyroidism	H/o of weight loss	Sweating Tremor Neck swelling	Decreased TSH	↑↑	Non specific	Myotonic
	Hypothyroidism	55	Proximal	−	+	+	−	−	+	+	+ Rhabdomyolysis	Signs of hypothyroidism	H/o weight gain	Myxoedema  Muscle pseudohypertrophy	Increased TSH	↑↑	Nonspecific	Normal
Infectious	Influenza	Variable	Proximal and Distal	+	+	−	+	−	−	−	+	Fever Malaise Rhinorrhea Muscle pain worse with movement	Cold weather H/o Ill contacts	Muscle weakness, tenderness, and swelling.	↑↑ Liver enzymes Positive PCR	↑↑	N/A	N/A