|
Frostbite Frostbite
is a change in the skin and subcutaneous tissue due to
localized cold injury when exposed to temperatures < 2 degrees C.
Some
predisposing factors include: 1.
Wet skin
or clothing 2.
Extreme
wind chill 3.
Constricting
garments 4.
Contact
with cold metal or water 5.
Individuals
with altered mental status (i.e. exhaustion,
dehydration, malnutrition) who are unable to get out of the cold 6.
Altered
response to cold stress due to comorbidities such as
peripheral vascular disease, diabetes mellitus, Raynaud’s phenomenon,
smoking
or alcohol abuse. 7.
African-Americans
and women may be at increased risk of frostbite1 8.
Can be
due to application of ice packs to reduce swelling from
musculoskeletal injuries so advise patients to interpose a cloth
between ice
packs and skin and limit treatment intervals to 20 minutes with a
minute or two
between applications. 9.
Case
reports of severe facial, upper airway, and esophageal
frostbite from recreational inhalation of halogenated hydrocarbons. The
pathophysiology of frostbite: 1)
Immediate
cold-induced cell injury and death a)
ice
crystallization both extracellularly and intracellularly à lysis of
cell
membranes à cell
death 2)
Subsequent
inflammatory process mediated by thromboxane A2,
prostaglandin F2-alpha, bradykinins, and histamine a)
This
results in tissue ischemia due to poor circulation to the
area and ultimately necrosis. 3)
During
rewarming, blood vessels leak fluid into the interstitium
causing edema. After reperfusion, edema increases and there is cellular
swelling as well. Thawing and refreezing lead to subsequent
inflammatory damage
to the affected area. Clinical
manifestations 1.
Most
often affects fingers, toes, noses, ears, cheeks, and chins. a.
Reports
of frostbite of the cornea in individuals who keep their
eyes open against strong winds. 2.
Patients
complain of cold, numbness, and clumsiness of affected
areas. 3.
Skin may
be insensate, white or grayish-yellow in color and hard
or waxy to touch. 4.
Usually
graded by degrees similar to burn injuries; based on depth
of tissue involvement a.
1st
degree- central area of pallor and anesthesia with surrounding
edema b.
2nd
degree- blisters containing clear/milky fluid surrounded by
edema and erythema developing in 24 hours c.
3rd
degree- injury is deeper and blisters are hemorrhagic,
progressing to black eschar over several weeks d.
4th
degree- subcuticular involvement that may include muscle and
bone in children. Complete tissue necrosis. Gangrene possible Diagnostics 1)
Used to
determine the extent of tissue involvement, response to
therapy and long-term tissue viability 2)
Plain
radiographs: may show coincidental trauma or cold-induced
soft tissue swelling. a)
Late
radiographs may show bony destruction and damage to growth
plates in children. 3)
Technetium
(Tc)-99 scintigraphy: used to predict long-term
viability of affected tissue with goal of earlier debridement or
amputation
rather than several week delay for demarcation. Also used to monitor
response
to topical therapy 4)
MRI/MRA:
assess tissue viability with visualization of occluded
blood vessels. Still limited experience. Treatment 1)
Preshospital
Care: a)
Get
patient to warm environment as soon as possible. Avoid
rubbing, pressure, and mechanical trauma by using pads/splints to
affected
area. b)
Remove
wet clothing. c)
Avoid
walking on frostbitten feet to avoid tissue damage. d)
Do not
rewarm if there is a possibility of refreezing before
reaching definitive care as this may result in further tissue damage. e)
Avoid
placing affected area in hot water or using stoves/fires to
rewarm as this may result in burns to insensate tissue. 2)
Definitive
Care in the hospital: a)
Rewarm
with immersion in water between 40-42 degrees centigrade.
(104-108F). Higher temperatures may result in burns. Dry heat is
difficult to
regulate and not recommended. Rewarm until the skin is warm,
red/purple, soft,
and pliable, usually 15-30 minutes. i)
Rewarming
is often associated with itching and pain, may need
analgesics (i.e. opioids).
b)
Elevate
to decrease edema c)
Bulky,
sterile dressings to affected area i)
Apply
nonadherent gauze as first dressing layer, avoid occlusive
dressing d)
Maintain
aseptic technique during wound treatment e)
Protect
lower extremity wounds with a cradle and upper extremities
with sterile sheets f)
Daily
hydrotherapy to improve range of motion g)
Splinting
may be required to prevent contracture formation h)
Tetanus
prophlyaxis i)
Thrombolysis:
frostbite is associated with vascular thrombosis.
Patients at high risk for life-altering amputation (multiple digits,
proximal
amputation) without contraindications to use tPA who present within 24
hours of
injury, intra-arterial tPA is recommended with repeat angiograms. j)
Drain,
debride and bandage large non-hemorrhagic bullae that
interfere with movement. Drain hemorrhagic bullae by aspiration but no
debridement necessary. Minor bullae may be left intact. k)
Prophylactic
antibiotics are controversial. Nevertheless,
parenteral antibiotics
should be given at the earliest signs of infection. Cover for staph,
strep, and
pseudomonas species. l)
Topical
aloe and oral ibuprofen appear to limit inflammation
although evidence is limited. m)
Early
surgical consultation to direct further management (i.e.
hydrotherapy, tissue debridement, escharotomy, fasciotomy, and delayed
amputation) Sequelae
of Frostbite Injury 1.
Infection/gangrene 2.
Autoamputation
of affected area 3.
Cold
hypersensitivity with subsequent increased risk of frostbite 4.
Atrophy
of muscle, bone, nerves, and tendons 5.
Arthritis 6.
Vasospastic
attacks 7.
Chronic
paresthesias or decreased sensation (esp. of hands) to
affected area References 1.
DeGroot, DW, Castellani, JW, Williams, JO, Amoroso, PJ.
Epidemiology of U.S. Army cold weather injuries, 1980-1999. Aviat Space
Environ
Med 2003; 74: 564. 2. Mechem
CC. Frostbite. Uptodate. February 11, 2008. 3. Britt
LD, Dascombe WH, Rodriguez A. New horizons in
management of hypothermia and frostbite injury. Surgical Clinics of
North
America. April 1991 |