Biology Reference
In-Depth Information
rapidly falling hemoglobin must be addressed, it is crucial to remain cognizant of pos-
sible hemoglobinuric nephropathy and resulting ARF that may be poorly responsive
to diuretics or dialysis (
Table 4.1
; Mebs et al., 1978). Therefore, hematocrit should be
maintained with concomitant serial evaluation of renal function (i.e., infuse PRBCs
sufficient to sustain low normal hemoglobin in the setting of an evolving nephropa-
thy). Thrombocytopenia can be addressed with platelet transfusion. There are no data
regarding treatment of
Thelotornis
or any other consumptive coagulopathic envenom-
ing with medications used for endotoxin-related DIC such as the recombinant anti-
thrombotic, α-drotrecogin. Similarly, use of FFP/cryoprecipitate is controversial and of
unproven efficacy, but could be considered in life-threatening cases (see later). Heparin
and fibrinolytics can cause further uncontrolled bleeding and are absolutely contraindi-
cated, although some data suggest possible efficacy (see later).
Antivenom Against
R. tigrinus
This antivenom first became available in 1986 and was raised in both rabbits and goats
(Kawamura et al., 1986). The rabbit- and goat-derived antivenoms (The Japan Snake
Institute, Japan) were tested in small groups of mice and reportedly neutralized 60 μg
[24 murine minimal lethal doses (MLD)] and 200 μg (80 MLD) of
R. tigrinus
venom,
respectively (Kawamura et al., 1988). Shortly after production and initial animal test-
ing, the rabbit-derived antivenom was used to successfully treat a serious case of
R.
tigrinus
envenoming with DIC (Wakamatsu et al., 1986). There was dramatic reversal
of a consumptive coagulopathy similar to the previously discussed cases of
D. typus
envenoming treated with anti-
D. typus
antivenom (see previous section and
Table 4.1
).
Another similarity with management of
D. typus
envenoming is the efficacy of anti-
R. tigrinus
antivenom used in treatment of envenoming with delayed presentation. The
patient in the case noted earlier presented some 50 h after the bite and was effectively
treated with antivenom (Wakamatsu et al., 1986).
Similar efficacy was reported with anti-
R. tigrinus
antivenom used in two cases docu-
mented by Kikuchi et al. (1987). In one of these cases, a pediatric patient was treated
almost 48 h after a bite from a presumed
R. tigrinus
. The patient presented with con-
sumptive coagulopathy, hematuria, and hemorrhagic diathesis (Kikuchi et al., 1987). The
coagulopathy was reversed within approximately 12 h after infusion of one ampoule of
antivenom (Kikuchi et al., 1987). Assessment of several cases of
R. tigrinus
envenom-
ing suggested that there was notable variability in time between the bite and develop-
ment of systemic clinical effects (4-30 h; Kikuchi et al., 1987; Ogawa and Sawai, 1986;
Wakamatsu et al., 1986). Kikuchi et al. (1987) observed that microhematuria, detected
1 h after the bite in one case, might be an early sign of developing systemic hemorrhagic
diathesis. Thus, careful clinical evaluation of patients bitten by
R. tigrinus
may facilitate
early recognition of an evolving systemic envenomation and thereby expedite procure-
ment and administration of antivenom.
Another pediatric case featured consumptive coagulopathy and hemorrhagic dia-
thesis (Akimoto et al., 1991). The patient was treated 21.5 h postenvenoming with
one ampoule of caprine-derived anti-
R. tigrinus
antivenom. Within 5 h, the coagu-
lopathy and hemorrhage had been controlled, and the patient showed rapid clinical
improvement (Akimoto et al., 1991).
