Biology Reference
In-Depth Information
(E)
(F)
Plate 4.92
(
Continued
)
(E and F) Western diamondback rattlesnake (
Crotalus atrox
)
envenoming.
Note the necrosis of the distal phalangeal skin in
Plate 4.92
E. The patient in
Plate 4.92
F exhibits extensive blistering, superficial necrosis, edema, and lymphadenopathy.
Plate 4.92A-D
, photos copyright to David A. Warrell;
Plate 4.92
E and F, photos copyright to
Julian White.
Philodryas olfersii latirostris
—As detailed in Section 4.4.4, this case described
a vertiginous syndrome that developed 4-6 days after a bite from this species that
caused no signs of envenomation. Due to the natural history of common causes of
vertigo, this case report cannot be confidently linked to a medically insignificant bite
after the aforementioned timeline (see Section 4.4.4). Evidence-based clinical anal-
ysis is essential when considering a case involving a species of unknown medical
importance. As discussed in Section 4.4.4, common causes of vertigo are far more
likely etiologies than the delayed effects of an otherwise inconsequential snakebite.
These should be given first consideration and emphasized unless clear evidence for
alternative causes is procured.
Hydrodynastes gigas
—Initially minor local effects of a bite from a captive speci-
men were reportedly followed 9 h later by a series of concerning symptoms and signs,
including an alleged movement disorder/transient paresis (
Table 4.1
; Section 4.4.3).
This case contains features strongly suggesting somatosensory amplification precipi-
tated by stress/anxiety (see Section 4.5.2). Aside from the local edema and pain, there
are no data or information in the report that links the reported symptoms/signs (particu-
larly the much delayed “paralysis,” dysarthria, etc.) causally to any specific effects of
the bite. One must distinguish between association, which may be coincidental or cir-
cumstantial, and causation. The brief tachycardia and premature atrial complexes spon-
taneously resolved and the local edema was said to have lasted about 5 days, although
the patient reported (via telephone follow-up only) that the “muscle pain and weak-
ness” persisted for almost 2 months. Since there was no further formal follow-up/medi-
cal review including physical examination, and investigations (see Section 4.4.3), these
symptoms cannot be properly evaluated. Therefore, this unusual case does not provide
sufficient evidence to support systemic effects of a bite inflicted by this species. In the
few other documented cases, only mild-to-moderate local effects resulted from bites by
this species (
Table 4.1
).
Macropisthodon rhodomelas
(blue-necked keel-back)
—The single report of a
bite from this species was authored by a zoologist bitten by a specimen approximately
