Spider bites: Difference between revisions

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*[[Brown recluse spider bite]]
==Background==
*[[Black widow spider bite]]
*Standard [[abscess]] are not typically due to spider bites and should not be diagnosed as such
===Background===
*Red hourglass on otherwise black spider
===Mechanism===
Envenomation causes release of acetylcholine and norepinephrine from the nerve terminals causing muscle cramps, tachycardia and hypertension
=== Clinical Features ===
#Local
##Pinprick sensation; then increasing local pain that may spread to entire extremity
##Erythema appears 20-60 min after the bite
##Pain begins to abate after several hours and disappears by 2-3d
#Systemic
##Muscle cramp-like spasms in large muscle groups (although exam rarely reveals rigidity)
##Pain becomes generalized
###Severe abdominal wall musculature pain and cramping
##HA, n/v, diaphoresis, photophobia, dyspnea
##A-fib, myocarditis, priapism, and death are rare


=== Treatment ===
===Clinically important spider genera by geographic region===  
#Pain and muscle spasms
* North America 
##Opiods and benzos
** Loxosceles (e.g. [[brown recluse]])
#Systemic illness
** Latrodectus (e.g. [[black widow]])
##Antivenin
** Tegenaria
###Consider for:
* South America
####Children
** Loxosceles
####Pregnant women
** Latrodectus
####Elderly
** [[Phoneutria]] (e.g. [[armed spider]])
* Africa
** Loxosceles
** Latrodectus
* Europe
** Loxosceles
** Latrodectus
* Australia
** Atrax (e.g. [[funnel-web spider]])
** Hadronyche (e.g. [[funnel-web spider]])
** Latrodectus 
* Asia
** Latrodectus
*Other
**[[Tarantula spider bite]]


=== Disposition ===
===Visual Spider Identification===
#Consider admission for:  
<gallery mode="packed">
##Symptoms of moderate envenomation
File:Tarantula640px-Brachypelma smithi 2009 G03.jpg|[[Tarantula]]
##Pregnant women
File:Western Black Widow (Latrodectus hesperus).jpg|[[Black widow spider]]
##Children
File:Brown Recluse.jpg|[[Brown recluse]]
##Pts w/ preexisting cardiovascular disease or HTN
File:p nigreventer.jpeg|[[Armed spider]] (''phoneutria nigreventer'')
File:Funnel Web Spider.png|[[Funnel-web spider]] (Hadronyche versuta)
</gallery>


==Tarantula==
==Clinical Features==
===Clinical Features===
===History===  
#Abdominal hairs may be flicked a short distance when threatened
* Determine circumstances of bite to assess consistency with spider habitat and behavior   
##Rarely penetrate human skin but can imbed deeply into conjunctiva and cornea
** Indoors vs outdoors
#Bites can be painful but systemic symptoms other than fever are unusual
** Day vs night 
** Geographic location (recent travel)
* Appearance of the spider if seen
* Dead spiders can be preserved in 70% EtOH and later identified by arachnologists or entomologist


===Management===
===Physical Exam===
#Red eye and pain after handling a tarantula necessitates an ocular exam
* No pathognomonic signs proving lesion is a spider bite
##Hairs may be difficult to detect on slit lamp
* Assess both bite site and for systemic signs
#Treatment is surgical removal of hairs and topical steroids
* Bite Site
** Location
*** Spider bites more common when clothing is tight against skin
** Number of bites
*** Multiple bites suggest parasitic insect and not spider
** Appearance of bite
*** Erythema, pallor, hemorrhage, induration, tenderness, paresthesia, vesicles
* Systemic findings
** Abnormal vital signs ([[tachycardia]] possible with black widow)
** [[Altered mental status]]
** [[Abdominal pain]]
** Diaphoresis
** Generalized [[rash]]
** Muscle fasciculations, spasm, or tenderness


==Review Questions==
==Differential Diagnosis==
<quiz display=simple>
{{Bites and stings DDX}}
{Environmental emergencies question – Regarding black widow and brown recluse spider envenomations, which of the following is FALSE?
 
|type="()"}
==Evaluation==
-Black widow spiders (BWS) are found in the temperate regions of six continents and are widespread through North America, including the western United States (California included).
===Workup===
-Signs and symptoms associated with BWS (e.g. diffuse pain, muscle cramps, tachycardia, and hypertension) usually develop begin within 30 to 120 minutes of the envenomation.
 
-After antivenom for BWS is administered, symptoms typically resolve within 30 minutes, with complete relief within 2 hours.
===Diagnosis===
+Brown recluse spider (BRS) envenomation is most common in west coast states, such as California.
*Typically a clinical diagnosis
||'''Harwood-Nuss – 1734-1739. Although BWS occur in Southern California, BRS are most common in the southern Midwestern states (but not California). Note that BRS have more local toxicity with eschar formation and necrosis, and these should not be debrided or excised. BRS may result in hemolysis and rhabdomyolysis. There is no antivenom available for BRS in the US, but there is one for BWS, which manifest severe life-threatening systemic signs.'''
 
-Most bites from BRS have a benign clinical course, but necrosis with induration and eschar formation may occur, and systemic effects, such as fever, chills, headache, malaise, arthralgia, and myalgias progress after more than 24 to 48 hours and resolve by 72 to 96 hours post bite.
==Management==
</quiz>
* Clean area of bite
* [[Tetanus prophylaxis]]
* [[analgesia|Analgesics]]
* Hydration
* Surgical follow up if indicated for debridement of necrotic area 
* [[Antivenin]] is indicated only for specific envenomation  
* No proven benefit for [[corticosteroids]]
* No indication for antibiotics unless concern for [[cellulitis]]
 
==Disposition==




==See Also==
==See Also==
*[[Bites and Stings]]
*[[Bites and Stings]]
*[[Envenomation]]


===Sources===
==External Links==
*Tintinalli
 
*Rosen's
 
==References==
<references/>
* Boyer LV, Binford GJ, Degan JA. Spider Bites. In Auerbach PS, Cushing TA, Harris NS. Auerbach’s Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017: 993-1016.


[[Category:Environ]]
[[Category:Environmental]]
[[Category:Toxicology]]

Latest revision as of 13:28, 29 May 2022

Background

  • Standard abscess are not typically due to spider bites and should not be diagnosed as such

Clinically important spider genera by geographic region

Visual Spider Identification

Clinical Features

History

  • Determine circumstances of bite to assess consistency with spider habitat and behavior
    • Indoors vs outdoors
    • Day vs night
    • Geographic location (recent travel)
  • Appearance of the spider if seen
  • Dead spiders can be preserved in 70% EtOH and later identified by arachnologists or entomologist

Physical Exam

  • No pathognomonic signs proving lesion is a spider bite
  • Assess both bite site and for systemic signs
  • Bite Site
    • Location
      • Spider bites more common when clothing is tight against skin
    • Number of bites
      • Multiple bites suggest parasitic insect and not spider
    • Appearance of bite
      • Erythema, pallor, hemorrhage, induration, tenderness, paresthesia, vesicles
  • Systemic findings

Differential Diagnosis

Envenomations, bites and stings

Evaluation

Workup

Diagnosis

  • Typically a clinical diagnosis

Management

Disposition

See Also

External Links

References

  • Boyer LV, Binford GJ, Degan JA. Spider Bites. In Auerbach PS, Cushing TA, Harris NS. Auerbach’s Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017: 993-1016.
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