3
d.
Lymphangitis: venom absorbed rapidly through lymphatics (which are highly
susceptible
to
destructive
effects)
e.
Petechiae,
Vesicles, Hemorrhagic Bullae:
- will occur in most untreated rattlesnake envenomations
- rarely see when treated early with adequate antivenom
- usually occur at 6-36 hr after bite (vesicles may appear within 3 hr)
f.
Necrosis,
Tissue
Destruction:
- due to direct venom effects (not increased tissue pressures, even if venom
injected IM)
- probably can totally prevent if adequate antivenom is given within 2 hours of bite
2.
Systemic:
a.
Nausea,
Vomiting: common (early onset may indicate severe envenomation)
b.
Weakness, Diaphoresis, Chills, Dizziness/Vertigo, Syncope: common with all pit
vipers
-
proportional
to
severity
c.
Change
in
Taste:
may complain of minty, rubbery, metallic taste
d.
Increased
Salivation
e.
Fever
f.
Tingling, Numbness in Scalp/Face/Fingers/Toes: can occur within 10 min and
indicates
moderate
-
severe
envenomation
g.
Fasciculations in Face/Neck/Back/Involved Extremity: can occur early (within 10
min)
and
indicate
severe
envenomation
h.
Visual
Disturbances: blurred vision, yellow vision, blindness (due to retinal
hemorrhages)
i.
Tachycardia,
Bradycardia
j.
Hemorrhage,
Hemolysis:
- bleeding from wounds, gingival bleeding, epistaxis, hematuria, hematemesis,
melena, lower GI bleeding, pulmonary bleeding, peritoneal hemorrhage, cerebral
hemorrhage
- can occur as early as 6 hr (and fatal hemorrhage has been reported 1 hr after
rattlesnake bite); more commonly 12-72 hr after bite
-
systemic
bleeding
only occurs in moderate to severe envenomation (not seen in
copperhead bites)
- most coagulopathic effects secondary to proteinases acting at various sites in the
coagulation
cascade
k.
Hypotension, Shock:
- can occur rapidly in severe envenomation
- early, due to pooling of blood (extremities, pulmonary bed, splanchnic bed)
- later, may be due to loss of volume (bleeding and third spacing of plasma) and
hemolysis (this form usually presents 6-26 hr after envenomation)
- generally little effect from decreased cardiac contractility
l.
Pulmonary
Edema:
-
common
in
severe
envenomation
- secondary to injury to intimal linings of pulmonary vasculature and pooling of
blood in major vessels & capillary beds of lungs
- compounded by direct cardiodepressant factor in some venoms
m.
Oliguria,
Anuria: multifactorial
- hypotension with resultant decreased GFR (#1)
- hemoglobinuria and myoglobinuria with renal tubular obstruction
- ATN secondary to arteritis and fibrin deposition in capillary lumina of kidneys
n.
Paresis,
Paralysis:
-
seen
with
eastern
diamondback
(Crotalus adamanteus)
and Mojave rattlesnakes
-
uncommon
with
other
rattlesnakes
o.
Respiratory
Failure:
- uncommon with pitviper bites (except Mojave)
