there is a patient, 26 years old, male complain: abdomen and back stiff and pain history: hyperthyroidism about 10 years, in the begainning medicine could control the thyroid function, when the thyroid became normal, stopped the therapy , HT recurred. now normal. PE: muscle of the abdomen and back is stiff, like a board, need help when he want to get up. but the tone and strength of the four extremities muslce is normal. sensation is normal. right hoffman s sign(+). bilateral babinski s sign (+).bilateral trepidation sign（+），bilateral ankle clonus(+). hyperhidrosis . test: normal EMG in four extremities, back and abdomen muslce can t relax, but no rigidity potential. normal electrolyte . thanks a lot