2
B. Disposition:
1.
Local
reaction:
- discharge with instructions on bee avoidance
2.
Systemic
reaction:
- admit if significant (to ICU prn)
- at discharge: bee avoidance instructions; Rx for injectable epi (have patient return for instructions in
use); referral to allergist for possible immunotherapy (all moderate severe anaphylactic reactions; all
adults with mild anaphylactic reactions [hives only]; all with serum sickness; all with toxic reactions)
- > 60% chance of recurrence of anaphylaxis
- immunotherapy 97% effective in preventing recurrence
IV. Spiders: > 60 spider species implicated in bites in the U.S.
A.
Widow
Spiders (Latrodectus sp.)
1.
Introduction: 5 known species in the U.S.
- best known = the "black widow" (Latrodectus mactans, L. hesperus, L. variolus); also: "red-legged
widow"
(L. bishopi) & the "brown widow" (L. geometricus)
- the female black widow is dark black with a 1.5 cm globular body & a ventral, red (orange or yellow)
marking
(typically
hourglass-shaped); leg span up to four cm
- can be found in all 48 contiguous states
- responsible for the majority of spider-related deaths
- only the female is dangerous; the male is too small to bite through human skin
- venoms of all species similar in composition & effects
- on a volume-for-volume basis, more potent than pit viper venom
- most deleterious component = a potent neurotoxin (alpha latrotoxin) - acts at nerve terminals
(especially neuromuscular junctions) - initially stimulates release of neurotransmitters, then blocks
transmission
by
depleting
synaptic
vesicles
2.
Clinical
Manifestations:
- bite itself often not noticed or may be felt as a pinprick
- site may be visible with tiny fang marks; area may be slightly warm and blanched with
surrounding
induration - swelling is minimal
- major symptoms usually appear 10 min - 2 hr after envenomation
- #1 = pain - begins at the bite site (dull ache); spreads to local muscle groups, then to larger regional
muscle groups of abdomen, back, chest, pelvis, and lower extremities; muscles spasm; peaks after
several hr
- respirations may be labored with spasm in chest muscles
- tachypnea, tachycardia, hypertension, dysrhythmias
- associated signs and symptoms include fever, headache, diaphoresis, nausea and vomiting,
restlessness/anxiety, periorbital edema, skin rash, reflexes may be increased
- no dermonecrosis or hemolysis
3.
Management:
a.
Field
Management:
- no specific first aid measures; ice application may reduce pain
b.
Hospital
Management:
- "ABC's" (oxygen, cardiac and pulse oximetry monitors, IV)
- monitor vital signs at frequent intervals
-
assess
underlying
medical
conditions
- routine admission labs; electrocardiogram & CXR if significant envenomation has occurred
-
update
tetanus
status
prn
- treat painful muscle spasms: ideal agent unclear...
- Diazepam and Narcotics in standard doses - probably best
