ENVENOMATIONS - Medicine for Mountaineering and Other Wilderness Activities - page 497

other pit viper bites. The reaction may be deceptively mild following the bite of a Mojave
rattlesnake and almost nonexistent after a massagua or pygmy rattlesnake bite.
The earliest symptom is pain or burning at the site of the bite, although some people ex-
perience relatively little pain. Shortly afterward the area begins to swell as fluid pours out
into the tissues. Bleeding usually produces a purple or green discoloration, but this change
may take several hours to appear.
If no further symptoms develop, the envenomation is mild and antiserum therapy is
rarely needed. However, the individual should be taken to a hospital, even though the reac-
tionappearsmild.Evidenceofmoresevereenvenomationmaytakeseveralhourstodevel-
op.
Numbness or a tingling sensation about the mouth or tongue, sometimes extending into
the scalp or involving the fingers and toes, and often associated with a metallic or rubbery
taste, commonly follows the bite of eastern diamondback and some western rattlesnakes.
Following moderate envenomation, the swelling and discoloration extend farther from
the site of the bite, blisters (sometimes large) that contain clear or bloody fluid appear, and
the regional lymph nodes (particularly in the armpit or the inguinal crease) become en-
larged and tender.
Severe envenomation is heralded by systemic reactions. The individual becomes weak
anddizzyanddevelopssignsofshock,particularlycoldandclammyskinandaweakpulse.
Prehospital Care for Crotalid Bites
MostofthevenomoussnakebiteswithintheUnitedStatesoccurinsituationswherehos-
pitalization is less than two hours away. The average interval between bite and hospitaliza-
tion has been reported to be thirty-five minutes. When a person can be hospitalized in such
a short time, the only treatment needed is limiting the spread of the venom and immobiliz-
ing the individual and the extremity.
Tourniquets have been recommended to help reduce spread of the venom, but no evid-
ence supports their effectiveness. They are potentially harmful and should not be used.
Wrapping the bitten extremity snugly and immobilizing it with a splint is a technique
devised by Struan Sutherland in 1978 for inhibiting the spread of venom from Australian
elapids. This procedure is not recommended for crotalid bites. Most bites by crotalids are
notlifethreatening,andtheprimarygoaloftherapyistolimitlocaltissuedamage.Immob-
ilizing the venom allows it to continue to digest the tissues in that area and significantly
increases the resulting destruction.
Incision and suction should not be attempted. Both procedures injure the tissues, and
experimental studies have clearly demonstrated that suction does not remove a significant
amount of venom.
The skin around the snakebite should be cleaned, the extremity should be immobilized
and kept at the same level as the heart, and the person should be transported to a hospital.