What Causes Severe Pain In Leg Radiating To The Ankle?

My husband is 53 years old with inclusion body myositis. We just got home from shopping and he is experiencing a sharp pain in his left leg, from just above the knew and down to the ankle. He is chilled, and despite 3 blankets can't get warm. He is also dizzy and nauseous. He is also diabetic. Checked is blood sugar and it is 168.