CASE PRESENTATION: A 49 year Hispanic male with history of left leg fasciotomy 15 years ago for compartment syndrome came with severe pain and weakness in lower extremities. Previous night he was in an outside hospital emergency room for severe headache, discharged with diagnosis of cluster headache. Next day he woke up with diffuse pain in the body, more in lower extremities. Due to worsening pain in lower extremities he came to Emergency room. Initial blood work revealed leukocytosis of 20.8, renal function within normal limits. Metabolic panel significant for hypokalemia (2.2), hypomagnesemia (1.5), hypophosphatemia (1.2), non-anion gap metabolic acidosis (bicarbonate 16) and creatinine kinase of 189. Urine analysis revealed glycosuria, urine potassium 57 and proteinuria. Imaging studies did not reveal any obvious pathology and routine urine toxicology was negative. Labs from previous night shows normal potassium (4.2). With aggressive replacement electrolytes were slowly improving. But he continued to have worsening right leg pain inspite of analgesia . On examination he noted to have a tender, firm and tense right lower lateral leg with non palpable dorsalis pedis pulse . Sensation was intact on the dorsum of right foot but decreased distally on toes. Corresponding lab shows potassium 8.1, creatinine kinase 15000. With concern for right leg compartment syndrome, emergently full right leg compartment fasciotomy was done. With hydration creatinine kinase and electrolytes returned to normal along with near normal function in his leg.