A number of findings can be used to define a patient with a snakebite.
Criteria for a snake bite - one or more of the following:
(1) presence of fang marks
(2) presence of local manifestations, such as pain and swelling at the site of the bite
(3) systemic manifestations, such as spontaneous bleeding or features of neurotoxicity
(4) the dead snake was brought in for identification
Findings that may indicate a severe envenomation:
(1) the snake is identified as very dangerous
(2) rapid, early extension of local swelling
(3) early tender lymphadenopathy
(4) early systemic symptoms (hypotension or shock, nausea and/or vomiting, diarrhea, severe headache, severe drowsiness, ptosis, ophthalmoplegia)
(5) early spontaneous systemic bleeding
(6) urine dark brown or black