Biology Reference
In-Depth Information
duloxetine), aspirin and other NSAIDS (e.g., naproxen, ibuprofen, diclofenac, etc.), clopi-
dogrel, etc.] may predispose to persistent bleeding or ecchymoses. Some medications may
have to be discontinued or reduced to renal dosages during the course of venom disease.
l
In the case of envenomation from a species for which specific commercial antivenom is
available,
do not delay
attempts to procure one to two ampoules as this can be effective for
up to 5-6 days postenvenoming.
l
Do not
underestimate the need for careful attention to the patient's constitutional require-
ments. For example, hospital bedding should be inspected carefully for insufficient cush-
ioning that may facilitate development of pressure-induced ecchymoses. In rural/field
locations, patients must be insulated from biting insects and trauma from natural exposures
to rough terrain, etc.
l
In patients with uncontrolled hemostatic defects,
even the least trauma should be avoided
.
Patients should remain on strict bed rest. Abdominal massage was sufficient to precipitate
fatal retroperitoneal bleeding in one patient. Therefore, physical examination should be care-
fully performed with the physician remaining cognizant of these significant risks.
4.6.2.17 Additional Considerations: The Possible Role of Hypersensitivity in
the Effects of Colubrid Bites
Available data suggest that the vast majority of medically significant bites from non-
front-fanged colubroid snakes are sustained while handling captive or field-collected
specimens (
Table 4.1
). This suggests (and is often the case) that those bitten have
had previous exposure to other snakes. This may include previous bites from non-
venomous species, handling shed skins, performing captive husbandry, and so on.
A smaller subgroup of patients may have a history of previous exposure to lyophi-
lized venoms and/or prior bites from venomous species, and possible treatment with
antivenom.
Type 1 IgE-mediated hypersensitivity is a recognized consequence of sensitiza-
tion after such exposures (Madeiros et al., 2007; Malina et al., 2008; Reimers et al.,
2000; Weinstein and Keyler, 2009). The multiple antigens shared among ophidian
venoms, Duvernoy's secretions, and some other buccal secretions may play a con-
tributory role in medically significant bites from colubroids (Weinstein and Keyler,
2009). Atopic tendencies may increase the severity of hypersensitivity reactions,
but does not increase their incidence. After a protracted bite (the snake was forcibly
removed after 2 min) on the right hand from a captive
P. patagoniensis
, a technician
maintaining an institutional venomous animal collection (implying the possibility
of previous exposure to venomous snakes and, possibly, venoms) experienced “con-
stant itching” that preceded progressive edema that ultimately involved the arm and
axilla (De Araújo and Dos Santos, 1997). Development of venom-specific IgE has
been demonstrated in a patient with repeated exposure to ringhals (
Haemachatus
haemachatus
) venom. The patient initially developed urticaria, but later experienced
increasingly generalized atopy on exposure (Wadee and Rabson, 1987). Among
eight patients with systemic effects from either
Vipera berus
(European viper or
adder) or
Vipera aspis
(European asp, Asp viper) envenoming, seven had both posi-
tive skin tests and IgE antibody against snake venoms, while testing was negative in
two patients who exhibited only local reactions to snakebites (Reimers et al., 2000).
