Transcript Coral Snake
Environmental
exposures
Nikki Waller, MD
Medical Student Clerkship
2009-2010
Self-Directed Learning Assessments
Snakes
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
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
Eastern Coral Snake venom is potent
neurotoxin
Symptoms:
• Tremor
• Salivation
• Respiratory paralysis
• Seizures
• Bulbar palsies( dysarthria, diplopia,
dysphsgia)
Coral Snake
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
Symptomatic Pts are admitted to ICU
Arizona Coral Snake
Sonoran(Arizona)
Coral Snake bite
does not require
treatment
Few symptoms
Local wound care
only
www.pitt.edu
Coral Snake Mimic
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
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
Hallmark of bite – fang marks
with local pain & swelling
Severity classification:
• Degree of local injury
Swelling, pain,
ecchymosis
• Degree of systemic
toxicity
Hypotension,
tacchycardia,
paresthesias
• Evolving coagulopathy
Thrombocytopenia,
elevated PT,
hypofibrinogenemia
Crotalinae (Pit Vipers) Bites
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
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
Diagnostic tests: CBC, Coags, Type &
Screen
Treatment:
• Resources: Arizona Poison Control 520626-6016
• Prehospital:
Minimize physical activity & remain calm
Immobilize bite site & place in neutral
position below heart
Crotalinae (Pit Vipers) Bites
Treatment (continued):
Cardiac monitor, IV’s, resuscitate based
on ACLS
Local wound care
• Remove FB
• Td Booster
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
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:
2 vials q 6h for additional 18 hours ( 3
more doses)
CroFab
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
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
DISPOSITION
• Observe for at least 8 hours
• Severe bites and anyone receiving
continued antivenin -> ICU
• Must warn patients about Serum
Sickness with Crofab
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
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
Symptoms: Pain &
swelling
Rare systemic
toxicity
Systemic SXS:
•
•
•
•
Diaphoresis
Paresthesia
Weakness
HTN
www.aintitcool.com
Gila Monster Habitat
www.pueblozoo.org
Hypothermia: Epidemiology
Defined as a core temperature < 35°C (95°F)
US Deaths:700 per yr
• Half > 65 yo
At Risk: Age Extremes & Altered sensorium
“Causes of Hypothermia: Clinical Settings
•
•
•
•
•
•
•
•
“Accidental” (environmental)
Metabolic
Hypothalamic and CNS dysfunction
Drug-induced
Sepsis
Dermal disease
Acute incapacitating illness
Iatrogenic (fluid resuscitation)
Hypothermia
ETIOLOGIES:
Metabolic causes
• Hypothyroidism, hypoadrenalism, hypopituitarism
• Each lead to a decrease in metabolic rate
• Hypoglycemia also may lead to hypothermia
CNS dysfunction
• Head trauma, tumor, stroke
• Wernicke disease
Potentially reversible with thiamine
Alcohol & Drugs
• In the US, most hypothermic patients are intoxicated
• Ethanol
Vasodilator & anesthetic and CNS depressant effects
Don’t Feel the Cold and Don’t respond to it
Hypothermia
ETIOLOGIES:
Sepsis
• Poor prognostic factor in patients with bacteremia
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
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
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
ECG Changes in Hypothermia:
T-wave inversions
PR, QRS, QT prolongation
Muscle tremor artifact
Osborn (J) wave
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
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
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
Rewarming: Active & Passive
• Stable cardiac rhythm & Vitals:
Passive rewarming
Noninvasive Active rewarming:
• Forced-air rewarming, warm O2 & warm IVF
• Less than 30° (86°F)
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)
Hypothermia:Treatment
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
Active core rewarming at 40°C:
• Pleural lavage
L thoracic cavity - heated fluid in proximity to the
heart
2 tubes – Instillation and removal
• Extracorporeal rewarming
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
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
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
Treatment:
• Chilblains & Trench foot: elevate, warm,
bandage
Rx: Nifedipine 20mg PO TID, Topical steroids,
prednisone, prostaglandin E1
• Frostbite: rapid rewarm with water at 42o C
(107o F) for 10-30 minutes
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
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
Heat Syncope:
• Cause: volume depletion, peripheral vasodilation,
decreased vasomotor tone
• R/O other causes of syncope
Heat Cramps:
• Painful muscle spasms of calves, thighs, shoulders
• Cause: dilutional hyponatremia from replacement with
free water
Heat tetany:
• Paresthesias of extremities & circumoral area
• Carpopedal spasms
• Cause: respiratory alkalosis from hyperventilation
Heat Emergencies: Heat Stroke
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
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
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
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
Hyperkalemia: normal protocol
Admission: ICU