In the past, hemlock
poisoning was only known for its neurotoxic effects; quite recently non-neurological features, consisting of
rhabdomyolysis and
acute renal failure, have been also described. Here we report our experience with these clinical findings, which we frequently observe in accidental hemlock
poisoning. Between 1972 and 1990 we studied 18 patients: 17 of them were poisoned by conline (an
alkaloid of Conium maculatim) in Apulia (Italy), and one by
cicutoxin (the active principle of water hemlock) in New Mexico (USA). In the non-rapidly-fatal cases we tested
myoglobinuria, serum muscle
enzymes, and renal function. In the patients with
acute renal failure we performed microscopical examination of kidney specimens; immunohistochemistry was carried out to identify
myoglobin and actin in tubules.
Coniine was detected in urine, serum, or tissues. Neurological features were present in all of our cases:
coniine had a
curare-like effect on the neuromuscular junction, whereas
cicutoxin was
convulsant on the central nervous system. In addition
rhabdomyolysis was noted in the 17 subjects poisoned by
coniine.
Acute renal failure was observed in five patients; it was confirmed by histological evidence of tubular
necrosis with intratubular deposition of
myoglobin and actin released by
rhabdomyolysis. Our cases seem to be the first with histopathologically proven acute tubular
necrosis in
coniine intoxication. In conclusion, in hemlock
poisoning neurotoxic manifestations may be accompanied by
rhabdomyolysis and acute tubular
necrosis; increased awareness of these clinical features is recommended in order to improve the diagnostic and therapeutic procedure.