A 30 year old man, a mechanic by profession came to the emergency department complaining of generali

A 30 year old man, a mechanic by profession came to the emergency department complaining of generalized body rigidity of two days duration. He has no Hx of fever, shortness of breath or cough.
On physical examination Vital signs are with in normal limit.
He is in opisthothonic position, he has torticolis and the deep tendon reflexes are exaggerated.
He is also found to have carpopedal spasm.

With the above brief hx and physical examination answer the following questions as thoroughly as possible.

1. What do you think has happened to this patient? What are the possible causes?
2. What do you like to extract further to arrive at a relevant working diagnosis?
3. What battery of tests would you like to run on this patient?
4. Briefly outline the possible lines of treatment.