Neurotoxicity of European viperids in Italy: Pavia Poison Control Centre case series 2001-2011.
BACKGROUND
Some clinical aspects about neurotoxicity after snakebites by European viper species remain to be elucidated.


OBJECTIVE
This observational case series aims to analyze neurological manifestations due to viper envenomation in Italy in order to describe the characteristic of neurotoxicity and to evaluate the clinical response to the antidotic treatment, the outcome, and the influence of individual variability in determining the appearance of neurotoxic effects.


METHODS
All cases of snakebite referred to Pavia Poison Centre (PPC) presenting peripheral neurotoxic effects from 2001 to 2011 were included. Cases were assessed for time from bite to PPC evaluation, Grade Severity Score (GSS), onset/duration of clinical manifestations, severity/time course of local, non-neurological and neurological effects, and antidotic treatment.


RESULTS
Twenty-four were included (age, 3-75 years) and represented on average of 2.2 cases/year (about 5% of total envenomed patients). The mean interval time of PPC evaluation from snakebite was 10.80 ± 19.93 hours. GSS at ED-admission was 0 (1 case), 1 (10 cases), and 2 (13 cases). All patients showed local signs: 41.6%, minor; 58.4%, extensive swelling and necrosis. The main systemic non-neurological effects were as follows: vomiting (86.7%), diarrhea (66.7%), abdominal discomfort (53.3%), and hypotension (20%). Neurotoxic effects were accommodation troubles and diplopia (100%), ptosis (91.7%), ophtalmoplegia (58.3%), dysphagia (20.8%), drowsiness (16.6%), cranial muscle weakness (12.5%), and dyspnea (4.2%). Neurotoxicity was the unique systemic manifestation in 9 cases; in 4 cases, they were associated with only mild local swelling. In 10 patients the onset of neurotoxic effects followed the resolution of systemic non-neurological effects. Antidote was intravenously administered in 19 (79.2%) patients. The mean duration of manifestations in untreated versus treated groups was 53.5 ± 62.91 versus 41.75 ± 21.18 hours (p = 0.68, local effects) and 9.77 ± 3.29 versus 8.25 ± 12.23 hours (p = 0.1, systemic non-neurological effects) and 43.4 ± 14.69 versus 26.58 ± 20.62 hours (p = 0.03, neurotoxic effects).


CONCLUSIONS
Neurotoxicity may appear late (11 hours after the bite in 58.3% of cases), in contrast with the data reported in medical literature. Neurotoxic effects have been reversible in all cases and may be the unique systemic manifestation of envenomation. Neurotoxic effects are shorter in treated group. The antidotic treatment of patients considered as GSS 2 only for neurotoxic effects (with mild local effects) may not be necessary. Variable factors such as different amount of venom injected, concentration of PLA2 component, and individual susceptibility may explain the less percentage of patients presenting neurotoxic effects.
Poison Control Centre and National Toxicology Information Centre, Toxicology Unit, IRCCS Maugeri Foundation and University of Pavia , Pavia , Italy.
D
D
Lonati
A
A
Giampreti
O
O
Rossetto
V M
VM
Petrolini
S
S
Vecchio
E
E
Buscaglia
M
M
Mazzoleni
F
F
Chiara
M
M
Aloise
A
A
Gentilli
C
C
Montecucco
T
T
Coccini
C A
CA
Locatelli
D015746:Abdominal Pain / Q000209:etiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000997:Antivenins / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000209:etiology; D004172:Diplopia / Q000209:etiology; D004636:Emergency Service, Hospital; D005094:Exophthalmos / Q000209:etiology; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D020258:Neurotoxicity Syndromes / Q000209:etiology* / Q000517:prevention & control; D011039:Poison Control Centers; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012909:Snake Bites / Q000453:epidemiology / Q000503:physiopathology* / Q000628:therapy*; D017819:Viperidae; D014839:Vomiting / Q000209:etiology
D000997:Antivenins