Download Coral Snake

Environmental
exposures
Nikki Waller, MD
Medical Student Clerkship
2009-2010
Self-Directed Learning Assessments
Snakes
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8,000 venomous snake bites/yr in US
~10 deaths/yr
25% bites are dry bites
Venomous:
1. Imported snakes
2. Coral Snakes
3. Crotaline Snakes/Pit Vipers
Rattlesnakes
Copperhead
Water Moccasin
Massasauga
www.zanesville.ohiou.edu
Clinical Effects
www.rk19-bielefeld-mitte.de
Coral Snake
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Brightly Colored
Black-Red-Yellow
pattern
RED touches
YELLOW = kill a
fellow
vs
Red on Black =
venom lack
ONLY Eastern Coral
Snake bite requires
treatment
www.zanesville.ohiou.edu
Coral Snake
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Eastern Coral Snake venom is potent
neurotoxin
Symptoms:
• Tremor
• Salivation
• Respiratory paralysis
• Seizures
• Bulbar palsies( dysarthria, diplopia,
dysphsgia)
Coral Snake
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Admit for 24-48 hours observation
ALL patients with POTENTIAL
envenomation – 3 vials of antivenim
Antivenim (M fulvius)
• At least 3 vials
• If sxs – additional doses
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Symptomatic Pts are admitted to ICU
Arizona Coral Snake
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Sonoran(Arizona)
Coral Snake bite
does not require
treatment
Few symptoms
Local wound care
only
www.pitt.edu
Coral Snake Mimic
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www.stetson.edu
jungledomain.org
Red and yellow, kill
a fellow; red and
black, friend of
Jack."
Coral Snakes in the US
www.backyardnature.net/
snakvenm.htm
Crotalinae (Pit Vipers) Bites
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Identified by
• 2 retractable fangs
• Heat sensitive
depressions (pits)
located between each
eye & nostril
Clinical Effects depend on:
• Size & species of snake
• Age & size of victim
• Time since bite
• Characteristics of bite
Crotalinae (Pit Vipers) Bites
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Hallmark of bite – fang marks
with local pain & swelling
Severity classification:
• Degree of local injury
 Swelling, pain,
ecchymosis
• Degree of systemic
toxicity
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Hypotension,
tacchycardia,
paresthesias
• Evolving coagulopathy
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Thrombocytopenia,
elevated PT,
hypofibrinogenemia
Crotalinae (Pit Vipers) Bites
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Any 1 of the 3 classes = envenomation
No sxs at 8-12 hours = no bite or dry bite
All envenomations have swelling at 30 minutes
• Rarely onset up to 12 hours
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Degree of envenomation
• Minimal: local sxs only
• Moderate: systemic sxs and coagulation parameter
abnormalities
• Severe: extensive swelling, potentially life threatening
systemic signs, markedly abnormal coagulation
parameters that may result in bleeding
Crotalinae (Pit Vipers) Bites
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Diagnostic tests: CBC, Coags, Type &
Screen
Treatment:
• Resources: Arizona Poison Control 520626-6016
• Prehospital:
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Minimize physical activity & remain calm
Immobilize bite site & place in neutral
position below heart
Crotalinae (Pit Vipers) Bites
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Treatment (continued):
Cardiac monitor, IV’s, resuscitate based
on ACLS
Local wound care
• Remove FB
• Td Booster
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Measure & Record limb circumference at
several sites above and below site of bite,
repeat q 30 minutes
Mark border of advancing edema q 30min
CroFab
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Polyvalent Crotalidae Immune Fab(CROFAB)
• Any pt with progressive swelling, systemic sxs or
coagulopathy
• Sheep derived antivenim
• Replaced Antivenin (Crotalidae) Polyvalent( equine
derived)
• Initial Dose: 4-6 vials IV
• Diluted in 250ml H20 & infused over 60 mins
• Dosing same for children, amount of diluent is adjusted
• @1HR, if any of 3 parameters have not halted, repeat
dose of 4-6 vials given
• Labs checked q4 h or after each round of Crofab
• End point is arrest of sxs and coagulopathy, IF NOT
KEEP TREATING
• After control of sxs, Protocol
CroFab
• @1HR, if any of 3 parameters have not
halted, repeat dose of 4-6 vials given
• Labs checked q4 h or after each round
of Crofab
• End point is arrest of sxs &
coagulopathy, IF NOT KEEP TREATING
• After control of sxs, Protocol as follows:
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2 vials q 6h for additional 18 hours ( 3
more doses)
CroFab
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The cost of CroFab is $ 750
per vial
Total cost of therapy for a
snakebite ranges from
$10500 (4-4-2-2-2 vials)
to $13500 (6-6-2-2-2
vials)
Average treatment Cost:
$10,000 per patient
Estimated 8,000 venomous
snakebites in the US each
year
Market potential of up to
US$80 million/yr
protherics.matinee.co.uk/
products/Critical_Care_Products.asp
Compartment Syndrome
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Pressure > 30 : limb elevation &
repeat CroFab dosing
Persistently elevated Pressure
• Mannitol 1-2 g/Kg IV over 30 minutes
• Surgical Consult for Fasciotomy
Crotalinae (Pit Vipers) Bites
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DISPOSITION
• Observe for at least 8 hours
• Severe bites and anyone receiving
continued antivenin -> ICU
• Must warn patients about Serum
Sickness with Crofab
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16% patients
7-14 days after therapy
Tx with Prednisone 60mg/d PO tapered over
1-2 weeks
Pit Vipers in the US
Western Diamondback
Rattlesnake Habitat
Eastern Diamondback
Rattlesnake Habitat
Gila Monster Bite
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Tenacious bite
Often lizard still attached
To remove:
• Place lizard on solid
surface
• Submersion in water
• Cast Spreader
• Local irritating flame
www.californiaherps.com
Local wound care
Search for teeth
No further treatment
required
www.mendosa.com
Gila Monster Bite
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Symptoms: Pain &
swelling
Rare systemic
toxicity
Systemic SXS:
•
•
•
•
Diaphoresis
Paresthesia
Weakness
HTN
www.aintitcool.com
Gila Monster Habitat
www.pueblozoo.org
Hypothermia: Epidemiology
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Defined as a core temperature < 35°C (95°F)
US Deaths:700 per yr
• Half > 65 yo
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At Risk: Age Extremes & Altered sensorium
“Causes of Hypothermia: Clinical Settings
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“Accidental” (environmental)
Metabolic
Hypothalamic and CNS dysfunction
Drug-induced
Sepsis
Dermal disease
Acute incapacitating illness
Iatrogenic (fluid resuscitation)
Hypothermia
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ETIOLOGIES:
Metabolic causes
• Hypothyroidism, hypoadrenalism, hypopituitarism
• Each lead to a decrease in metabolic rate
• Hypoglycemia also may lead to hypothermia
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CNS dysfunction
• Head trauma, tumor, stroke
• Wernicke disease
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Potentially reversible with thiamine
Alcohol & Drugs
• In the US, most hypothermic patients are intoxicated
• Ethanol
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Vasodilator & anesthetic and CNS depressant effects
Don’t Feel the Cold and Don’t respond to it
Hypothermia
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ETIOLOGIES:
Sepsis
• Poor prognostic factor in patients with bacteremia
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Severe infections, DKA, immobilizing injuries, and
various other conditions impair thermoregulatory
function
Trauma patients
• Resuscitation with room-temperature fluid & cold blood
• At risk: Pts undergoing massive volume replacement
Hypothermia: Physiology
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32° to 35°C (89.6°–95°F) = “mild” hypothermia
Excitation (responsive) stage
Body attempts to retain & generate heat
HR, CO & BP all rise
Below 32°C (89.6°F) = moderate hypothermia
Slowing (adynamic) stage
Progressive slowdown of bodily functions &
metabolism
Decrease O2 utilization & CO2 production
Below 30° to 32°C (86°–89.6°F) - shivering stops
Hypothermia: Cardiac
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Dysrhythmias at Temp < 30°C (86°F)
Typical sequence:
Sinus Brady ->
slow AFIB ->
VFIB
Myocardium - extremely irritable
• VFIB induced by rough handling of patient
Dysrhythmias:
Sinus bradycardia
AFIB or flutter
Nodal rhythms
AV block
PVCs
Ventricular fibrillation
Asystole
->
asystole
Hypothermia
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ECG Changes in Hypothermia:
T-wave inversions
PR, QRS, QT prolongation
Muscle tremor artifact
Osborn (J) wave
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Osborn (J) wave:
• Slow, positive deflection at the end of
the QRS complex
• Characteristic, not pathognomonic
Osborn Wave
Hypothermia
Pulmonary:
• Initial tachypnea -> decrease RR & TV
• Aspiration pneumonia risk - Bronchorrhea & depressed
gag reflex
• ABG: false high PO2 and PCO2 & lower pH
• Leftward shift of OxyHgb dissociation curve
thus impairing O2 release
CNS:
• Depression of consciousness
• SXS: Mild incoordination then confusion, lethargy &
coma
• Pupils may be dilated & non reactive
Hypothermia
Renal
• Cold diuresis c resultant volume losses
• Prone to rhabdomyolysis
• Prone to ARF from myoglobinuria &
hypoperfusion
Hematology
• Prone to intravascular thrombosis and
subsequent embolic complications
• Prone to DIC
• Prone to bleeding
Hypothermia: Diagnosis
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Rectal Temp
Some standard clinical thermometers
record only to 34.4°C (94°F)
Electronic thermometers with flexible
probes can continuously monitor
rectal, bladder or esophageal Temp
Hypothermia:Treatment
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ABCs
Cardiac Monitor, pulse Ox
Continuous or repeated Temperature
recordings
Drugs:
• IV thiamine 50 mg
• If FSBS low: 50 to 100 mL of D50
Hypothermia:Treatment
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Rewarming: Active & Passive
• Stable cardiac rhythm & Vitals:
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Passive rewarming
Noninvasive Active rewarming:
• Forced-air rewarming, warm O2 & warm IVF
• Less than 30° (86°F)
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Rapid rewarming until the temp is 30° to
32°C (86°–89.6°F)
• Minimize dysrhythmias
Hypothermia:Treatment
Passive rewarming:
1. Removal from cold environment
2. Insulation
 Active external rewarming:
Warm water immersion
Heating blankets set at 40°C
Radiant heat
Forced air ( BEAR Hugger)
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Hypothermia:Treatment
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Active core rewarming at 40°C:
• Inhalation rewarming
• Warmed, humidified air by face mask or ETT
• Heated IV fluids
• Warmed to 40°C (104°F)
• GI tract lavage
• Pulmonary aspiration if unprotected airway
• Bladder lavage
• Peritoneal lavage
• Potassium-free dialysis solution at 104°–113°F
• 2 catheters (instillation & removal)
Hypothermia:Treatment
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Active core rewarming at 40°C:
• Pleural lavage
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L thoracic cavity - heated fluid in proximity to the
heart
2 tubes – Instillation and removal
• Extracorporeal rewarming
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Pump-assisted cardiopulmonary bypass via femoral
vessels is the most common
Right atrial–aortic bypass using a median sternotomy
and heated hemodialysis
• Mediastinal lavage via thoracotomy
Local Cold Induced Injury
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Frostnip: less severe than frostbite, no
tissue loss, resolves with rewarming
Trench foot: cooling of tissue in a wet
environment at above freezing temp over
hrs to days
Chilblains(pernio): painful & inflamed
lesions from chronic & intermittent
exposure to damp non-freezing ambient
temp
Local Cold Induced Injury
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First Degree Frostbite: superficial injury;
edema, burning & erythema
Second Degree Frostbite: above +
blistering
Third Degree Frostbite: involves full
thickness skin & subdermal tissue
Fourth Degree Frostbite: involves above +
subcutaneous tissue, muscle, tendon &
bone
• Cyanotic & insensate tissue, hemorrhagic
blisters & skin necrosis
• Later becomes mummified
Local Cold Induced Injury
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Treatment:
• Chilblains & Trench foot: elevate, warm,
bandage
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Rx: Nifedipine 20mg PO TID, Topical steroids,
prednisone, prostaglandin E1
• Frostbite: rapid rewarm with water at 42o C
(107o F) for 10-30 minutes
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Rx: Narcs, ibuprofen, aloe vera, PCN G 500,000 u
PO q6 for 2-3 days
Debride clear blister
Don’t puncture Hemorrhagic blisters
NO DRY AIR REWARMING
Heat Emergencies
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Heat Exhaustion:
• Sxs: malaise, fatigue, weakness, dizziness,
syncope, HA, nausea, vomiting, myalgias,
diaphoresis, tachypnea, tachycardia,
orthostatic hypotension
• Temp: elevated to normal
• Sensorium and Neuro Exam: NORMAL
• Dx Work-up: Check CK to r/o Rhabdo
• TX: rest, evaporative cooling, IV fluids
• Dispo: D/C except Electrolyte abnormalities or
Co-morbidities
Heat Emergencies
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Heat Syncope:
• Cause: volume depletion, peripheral vasodilation,
decreased vasomotor tone
• R/O other causes of syncope
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Heat Cramps:
• Painful muscle spasms of calves, thighs, shoulders
• Cause: dilutional hyponatremia from replacement with
free water
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Heat tetany:
• Paresthesias of extremities & circumoral area
• Carpopedal spasms
• Cause: respiratory alkalosis from hyperventilation
Heat Emergencies: Heat Stroke
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Difference from Heat exhaustion is Altered Mental
Status & Definite elevated Temp
Core Temp 40 - 47o C
Neurologic Sxs: ataxia, confusion, bizarre
behavior, agitation, Szs, obtundation & Coma
Risk Factors: Age <4 or > 75yo; CHF, psych
illnesses, ETOH, dehydration, poverty, social
isolation, poor conditioning, no access to air
conditioning, poorly acclimated to warm weather,
medications (B-Blockers, Ca Channel Blockers,
Anti-cholinergics)
Heat Emergencies: Heat Stroke
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Diagnostic Work-up: CBC, Electrolytes,
CK, LFTs, ETOH level, Tox Screen, Coags,
UA, urine myoglobin, U preg, ABG, CXR,
EKG
Differential Diagnosis: sepsis, meningitis,
encephalitis, toxidromes (anticholinergic,
PCP, salicylates, sympathomimetics), DKA,
thyrotoxicosis, status epilepticus, stroke,
neuroleptic malignant syndrome,
malignant hyperthermia
Heat Emergencies: Heat Stroke
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Treatment:
ABCs
ETT if altered mental status, hypoxia or
diminished gag reflex
Volume Replacement: dehydrated &
prevent Rhabdomyolysis
Evaporative Cooling: disrobe pt; spray
tepid water at patient via surrounding fans
Treat shivering with Benzodiazepines
Heat Emergencies: Heat Stroke
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Aggressive Cooling: immersion cooling,
cold water gastric & urinary bladder
lavage, thoracostomy lavage,
cariopulmonary bypass
Seizures: treat with Benzos
Rhabdomyolysis:
• IV hydration, furosemide 40mg IV, Na Bicarb
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Hyperkalemia: normal protocol
Admission: ICU