98: Cold Injuries Flashcards
1
Q
What is the role of the hypothalamus in core body temperature regulation?
A
The hypothalamus serves as the central thermoregulation center, maintaining core body temperature by controlling cutaneous blood flow.
2
Q
What is the Hunting Reaction of Lewis and its significance in cold exposure?
A
The Hunting Reaction of Lewis is a paradoxical cyclic vasodilation that occurs during prolonged cold exposure to protect against skin necrosis from prolonged vasoconstriction.
3
Q
How does slow freezing affect tissues compared to fast freezing?
A
Slow freezing leads to the formation of extracellular ice crystals, which alter the osmotic properties of tissues. In contrast, fast freezing results in intracellular ice formation, which can cause more severe tissue damage.
4
Q
What factors predispose individuals to cold injuries?
A
Factors include skin conditions with transepidermal water loss, physical injuries, lean body mass, low physical fitness level, fatigue, dehydration, previous cold injuries, poor peripheral circulation, poor clothing insulation, old age, and associations with alcohol consumption, homelessness, and psychotropic drug use.
5
Q
What are the effects of increased blood viscosity in cold conditions?
A
Increased blood viscosity leads to vascular sludging, contributing to tissue damage and complications in cold injuries.
6
Q
What is the role of the hypothalamus in thermoregulation?
A
It is the central thermoregulation center that controls core body temperature by regulating cutaneous blood flow.
7
Q
What happens during slow freezing of tissues?
A
Extracellular ice crystals alter the osmotic properties of tissues and disturb the flow of water and electrolytes across cell membranes.
8
Q
What are the effects of fast freezing on tissues?
A
It leads to the formation of intracellular ice, which can cause significant tissue damage.
9
Q
How does cutaneous vasoconstriction occur in response to cold?
A
It is an immediate response to reduce blood flow, helping to maintain core body temperature.
10
Q
What is the impact of increased blood viscosity in cold conditions?
A
It leads to vascular sludging, which can impair blood flow and increase the risk of cold injuries.
11
Q
Why are newborns and the elderly more vulnerable to cold injuries?
A
They have impaired thermoregulation and are less able to adapt to cold environments.
12
Q
What is the significance of countercurrent exchange in the limbs?
A
It allows for efficient heat transfer, helping to maintain core body temperature during cold exposure.
13
Q
How does mild long-term exposure to cooling affect individuals?
A
It may lead to progressively better insulation of adipose tissue, making overweight persons more likely to survive prolonged cold exposure.
14
Q
What are the two classifications of skin cold injuries based on patient history?
A
- Freezing - clear associations with cold exposure by patient history. 2. Non-freezing - less likely to be associated or recounted by patients.
15
Q
What are the clinical effects of frostbite and how does it occur?
A
Frostbite occurs due to exposure to extremely cold air, liquids, or metals leading to initial vasoconstriction and formation of ice crystals causing metabolic derangements, electrolyte imbalances, membrane lysis, and cell death.
16
Q
What are the three categories of frostbite and their characteristics?
A
- FROSTNIP - Skin only; damage is reversible. 2. SUPERFICIAL - Skin and subcutaneous tissue; pain subsides to warmth. 3. DEEP - Extends to deep subcutaneous tissue; skin becomes white or bluish white; anesthesia present.
17
Q
What is the treatment goal for frostbite and its clinical implications?
A
The treatment aims to keep the body warm and maintain vasodilation to prevent further tissue damage and promote healing.
18
Q
What is frostnip and how is it characterized?
A
Mild frostbite affecting only the skin; damage is reversible with symptoms of severe cold, numbness, and no edema or bleb.
19
Q
What distinguishes superficial frostbite from deep frostbite?
A
Superficial frostbite affects skin and subcutaneous tissue with pain subsiding to warmth, while deep frostbite extends to deeper tissues, causing numbness and potential paralysis.
20
Q
What are common sites for frostbite?
A
Fingers, toes, ears, nose, and cheeks.
21
Q
What happens to the skin in deep frostbite?
A
The skin becomes white or bluish white and is totally numb with immobility of joints and extremities.
22
Q
What is the clinical effect of thawing in frostbite?
A
Thawing can exacerbate tissue damage through ischemia-reperfusion and increasing inflammation.
23
Q
What are the signs of severe frostbite?
A
Skin becomes numb, indurated, and may show large blisters after rewarming.
24
Q
What is the role of prostaglandins in frostbite?
A
High prostaglandins lead to increased vasoconstriction, platelet aggregation, and progressive tissue injury.
25
What is the most important preventive measure against frostbite?
Protective clothing, a warm hat, earflaps, and scarf, along with turning bare areas away from the wind are crucial for prevention.
26
What is the first consideration in the treatment of frostbite?
Recognizing hypothermia is the first consideration in frostbite treatment.
27
What is the recommended temperature range for rapid rewarming in frostbite treatment?
Rapid rewarming should occur in a water bath between 37°C and 39°C (98.6°F and 102.2°F) until the most distal parts of the body are flushed.
28
What are some adjunctive therapies for frostbite treatment?
Adjunctive therapies may include vasodilators, thrombolysis, and hyperbaric oxygen.
29
What is the most common iatrogenic cold injury procedure in the US?
The most common in-office procedure causing cold injury is cryodestruction using liquid nitrogen.
30
What are the significant reactions that can occur from cryodestruction?
Significant reactions can include pain, vesicles, large bullae, and hemorrhagic bullae, along with potential scarring and hypopigmentation.
31
What are some risk factors associated with self-inflicted cold injury?
Risk factors include low socioeconomic status, criminal behavior, incarceration, depression, suicidal ideation, and unstable home life.
32
What are the common chemicals that can cause self-inflicted cold injury?
Common chemicals include fluorinated hydrocarbons in propellants, refrigerants, and liquefied petroleum gases.
33
What are the potential sequelae of frostbite?
Potential sequelae include permanent hypersensitivity to cold, hyperhidrosis, squamous cell carcinoma, and frostbite arthritis.
34
What should be the first consideration in frostbite treatment?
Recognizing hypothermia.
35
What is advised to avoid after a frostbite episode?
Trauma, friction, pressure, massaging with snow, and refreezing.
36
When is surgical debridement best delayed after frostbite?
Until 1 to 3 months after demarcation.
37
What is a rare long-term outcome of frostbite?
Permanent hypersensitivity to cold or squamous cell carcinoma.
38
What are some significant reactions to localized tissue freezing?
Pain, vesicles, large bullae, and hemorrhagic crusting.
39
What chemicals can cause self-inflicted cold injury?
Fluorinated hydrocarbons in propellants, refrigerants, and liquefied petroleum gases.
40
What is the keystone of treatment for frostbite?
Rapid rewarming in a water bath between 37°C and 39°C (98.6°F and 102.2°F) until the most distal parts of the body are flushed.
41
What stage of frostbite is characterized by large blisters forming 2 days after rewarming?
This is Deep Frostbite. The blisters should be left intact, and the damaged parts should be elevated.
42
What is the likely cause of erythema and vesicles on the face after inhaling nitrites?
The likely cause is self-inflicted cold injury from inhalant abuse. Risk factors include low socioeconomic status, depression, and unstable home life.
43
What is the likely cause of hypopigmentation and scarring after cryosurgery?
The likely cause is Iatrogenic Cold Injury from cryodestruction using liquid nitrogen, which causes localized tissue freezing and cell death.
44
What are the predisposing factors for winter xerosis?
Predisposing factors include atopic dermatitis, ichthyosis, increasing age, and excessive washing. It is influenced by cold environments, especially in combination with low humidity.
45
What is acrocyanosis and how does it present?
Acrocyanosis is characterized by vasoconstriction that alters skin temperature and color, leading to blue to violaceous discoloration of the hands, feet, nailbeds, and face. It is persistent, accentuated by cold exposure, and does not involve trophic changes or pain.
46
What are the main causes of perniosis or chilblains?
Perniosis or chilblains are localized inflammatory lesions caused by continued exposure to cool temperatures above freezing. Contributing factors include dampness, wind, and an abnormal vascular response to cold and minor trauma.
47
What is a common condition caused by exposure to cool temperatures above freezing?
Perniosis or chilblains.
48
What are the symptoms of acrocyanosis?
Blue to violaceous discoloration of the skin, particularly in the hands, feet, and face, with no trophic changes and pain.
49
What exacerbates trench foot?
Dampness and cold, wet conditions at temperatures above freezing.
50
What is a key characteristic of winter xerosis?
Dryness of the skin, particularly on the lower extremities, during wintertime.
51
What is the effect of table salt and ice cubes on the skin?
They rapidly decrease the freezing point of water to below 0 °C, enhancing the ability to induce local frostbite.
52
What is the primary cause of perioral dermatitis with pyoderma?
Exposure to irritants such as nitrites and contact dermatitis.
53
What is the treatment for acrocyanosis?
There is no effective treatment; supportive measures to keep the skin warm are recommended.
54
What is the relationship between cold exposure and skin color in acrocyanosis?
Vasoconstriction alters skin temperature and color, leading to blue to violaceous discoloration.
55
What is a common symptom of frostbite?
Painful, sharply demarcated, dusky erythematous patches that may become bullous.
56
Scenario: A patient presents with blue to violaceous discoloration of their hands and feet, accentuated by cold exposure. What condition is this, and how does it differ from Raynaud phenomenon?
This is Acrocyanosis. It differs from Raynaud phenomenon as it is persistent, less sclerotic, and not painful, whereas Raynaud is episodic, often segmental, and painful.
57
Scenario: A patient develops dusky erythematous patches with a geometric pattern after applying salt and ice cubes to their skin. What is the mechanism of injury?
The mechanism involves salt rapidly decreasing the freezing point of water, enhancing the ability to induce local frostbite.
58
Scenario: A patient presents with persistent erythema of the face and hands after exposure to cold, wet conditions. What condition might this be, and what are the pathogenic factors?
This might be Non-Freezing Cold Injury. Pathogenic factors include cold, wet conditions, limb dependency, and constrictive footwear.
59
What are the characteristic symptoms of idiopathic perniosis?
Symptoms of idiopathic perniosis include edema of the papillary dermis, superficial and deep perivascular lymphocytic infiltrates, necrotic keratinocytes and lymphocytic vasculitis, thickening of blood vessel walls with potential obliteration of the vascular lumen.
60
What is the most important point in the management of pernio?
The most important point in the management of pernio is prevention, which includes adequate, loose, insulating clothing, appropriate warm housing and workplace, and avoiding tight garments that can compromise circulation.
61
What are the potential complications associated with chilblains lupus?
Chilblains lupus is associated with chronic cutaneous lupus, systemic lupus erythematosus, and secondary pernio linked to other connective tissue diseases, monoclonal gammopathies, hyperviscosity syndromes, and viral infections.
62
What are the symptoms of 'Pulling-Boat Hands' and its associated conditions?
Symptoms of 'Pulling-Boat Hands' include erythematous macules and plaques on the dorsum of the hands and fingers, development of small vesicles leading to itching, burning, and tenderness, associated with exposure to high humidity, cool air, and wind, resulting in nonfreezing cold injury.
63
What laboratory workup is suggested for conditions associated with pernio?
The suggested laboratory workup includes complete blood count with peripheral smear, serum protein electrophoresis, antinuclear and extractable nuclear antigen antibodies, rheumatoid factor, cold agglutinins, and antiphospholipid antibodies. This workup is performed only if the history and physical examination suggest a possible underlying systemic disease.
64
What are the common symptoms of pernio during colder months?
Acute, single or multiple burning, erythematous to violaceous macules, edematous papules, plaques, and nodules, along with itching, burning, or pain, and possible blisters, pustules, and ulceration.
65
What is the characteristic location of lesions in pernio?
Dorsal and plantar surfaces of the toes, but can also affect fingers, heels, nose, ears, calves, and thighs.
66
What is the typical resolution time for pernio lesions?
1 to 3 weeks, but they may become chronic in elderly people with venous stasis.
67
What is the management strategy for preventing pernio?
Prevention includes adequate, loose, insulating clothing, appropriate warm housing, and avoiding tight garments.
68
What is the relationship between chilblains lupus and systemic lupus erythematosus?
Chilblains lupus is a distinct disease variant of chronic cutaneous lupus or in the setting of systemic lupus erythematosus.
69
What are the associated conditions with pernio?
Pernio is associated with myeloproliferative disorders, connective tissue diseases, and other systemic conditions.
70
What are the symptoms of pulling-boat hands?
Erythematous macules and plaques on the dorsum of the hands and fingers, small vesicles, itching, burning, and tenderness.
71
What environmental factors contribute to pulling-boat hands?
Exposure to long periods of high humidity, cool air, and wind, along with repetitive hand trauma from rowing.
72
Scenario: A sailor develops erythematous macules and plaques on the dorsum of their hands after prolonged rowing in cold, humid conditions. What condition is this, and what are the contributing factors?
This condition is Pulling-Boat Hands. Contributing factors include prolonged exposure to high humidity, cool air, wind, and repetitive hand trauma from rowing.
73
Scenario: A patient presents with burning, erythematous macules on their toes during winter. What condition might this be, and what is the first-line treatment?
This might be Pernio/Chilblains. First-line treatment includes rest, warmth, and midpotency topical steroids applied up to twice daily until lesions resolve.
74
Scenario: A patient with systemic lupus erythematosus develops localized inflammatory lesions after cold exposure. What condition might this be, and what is the associated variant?
This might be Chilblains Lupus, a variant of chronic cutaneous lupus or systemic lupus erythematosus.
75
Scenario: A patient develops erythematous macules and plaques on their hands after exposure to cold and damp conditions. What condition is this, and what preventive measures can be taken?
This is Pernio/Chilblains. Preventive measures include wearing loose, insulating clothing, avoiding tight garments, and minimizing moisture.
76
Scenario: A patient develops burning, erythematous macules on their thighs after horseback riding in winter. What condition is this, and how can it be prevented?
This is Pernio/Chilblains. Prevention includes wearing baggy riding pants that provide insulation and do not compromise circulation.
77
Scenario: A patient develops erythematous macules and plaques on their hands after prolonged exposure to cool air and wind. What condition is this, and what are the contributing factors?
This is Pulling-Boat Hands. Contributing factors include prolonged exposure to high humidity, cool air, wind, and repetitive hand trauma.
78
Scenario: A patient develops erythematous macules on their hands after exposure to cold and damp conditions. What condition is this, and what are the characteristic locations?
This is Pernio/Chilblains. Characteristic locations include the dorsal and plantar surfaces of the toes, fingers, heels, nose, ears, calves, and thighs.
79
What is acquired cold urticaria and how does it manifest?
Acquired cold urticaria is a form of physical urticaria that occurs at sites of localized cooling, usually when the area is rewarmed. It manifests as wheal and flare-type reactions and/or angioedema, which can be indistinguishable from other forms of urticaria.
80
What genetic mutation is associated with familial cold urticaria?
Familial cold urticaria is associated with a mutation in the CIAS1 gene, which is responsible for cold-induced autoinflammatory syndrome.
81
What are the common symptoms of cold urticaria in patients with cryoglobulinemia?
Cold urticaria in patients with cryoglobulinemia may present with symptoms such as urticaria, fever, arthralgia, leukocytosis, and swelling of the oral mucosa and esophagus.
82
What is the recommended first-line treatment for acquired cold urticaria?
The first-line treatment for acquired cold urticaria is second-generation H1 antihistamines, which can be administered up to four times the standard dose.
83
What is cold erythema and how does it differ from cold urticaria?
Cold erythema is a related disorder characterized by erythema and pain without the presence of urticaria.
84
What is popsicle panniculitis and what triggers it?
Popsicle panniculitis is a nonfreezing injury that causes inflammatory reactions in the subcutaneous fat layer, commonly occurring in children. It is triggered by eating popsicles.
85
What is the typical presentation time for cold panniculitis after exposure?
1 to 3 days after exposure.
86
What is the significance of the ice cube test in diagnosing cold urticaria?
Wheals form on rewarming, indicating a reaction to cold exposure.
87
Scenario: A patient presents with erythema and pain after exposure to cold but no urticaria. What condition might this indicate, and how would you confirm the diagnosis?
This might indicate Cold Erythema. Diagnosis can be confirmed by observing erythema and pain without urticaria after cold exposure.
88
Scenario: A child develops tender erythematous subcutaneous nodules on their cheeks after eating popsicles. What is the likely diagnosis and treatment?
The likely diagnosis is Popsicle Panniculitis. Treatment involves reassurance and supportive analgesia as necessary. Lesions typically subside spontaneously within 2 to 3 weeks.
89
Scenario: A patient develops localized angioedema 48 hours after cold exposure. What rare condition might this indicate, and what genetic mutation is associated with it?
This might indicate Delayed Familial Cold Urticaria, which is associated with a mutation in the CIAS1 gene.
90
Scenario: A patient with cryoglobulinemia develops urticaria after cold exposure. What is the underlying mechanism, and what is the first-line treatment?
The underlying mechanism involves cryoglobulins, cold agglutinins, or cryofibrinogens. First-line treatment is second-generation H1 antihistamines, up to 4 times the standard dose.
91
Scenario: A patient develops urticaria and angioedema after swimming in cold water. What condition might this be, and what is the first-line treatment?
This might be Acquired Cold Urticaria. First-line treatment is second-generation H1 antihistamines, up to 4 times the standard dose.
92
What is the typical time frame for the development of an erythematous subcutaneous plaque after an ice cube challenge to the skin?
An erythematous subcutaneous plaque typically develops 12 to 18 hours after an ice cube challenge to the skin for 10 minutes.
93
What histological findings are associated with cold panniculitis after 24 hours?
After 24 hours, cold panniculitis shows a perivascular mixed infiltrate with neutrophils, lymphocytes, and histiocytes at the dermal-subcutaneous junction, followed by a well-developed lobular panniculitis at 48 to 72 hours.
94
What develops after an ice cube challenge to the skin?
An erythematous subcutaneous plaque typically develops 12 to 18 hours later.
95
What histological findings are associated with cold panniculitis after 24 hours?
A perivascular mixed infiltrate with neutrophils, lymphocytes, and histiocytes at the dermal-subcutaneous junction.
96
What is observed in cold panniculitis after 48 to 72 hours?
A well-developed lobular panniculitis with superficial and deep perivascular dermal lymphocytic infiltrate.
97
What is the typical clinical course of lesions caused by cold panniculitis?
Lesions typically subside spontaneously within 2 to 3 weeks.
98
What are some differential diagnoses for cold panniculitis?
Erythrocyanosis with nodules, sclerema neonatorum, and subcutaneous fat necrosis of the newborn.
99
How does the adipose tissue composition in infants affect their response to cold temperatures?
Infants have a higher content of saturated fatty acids in adipose tissue than adults, leading to solidification at less-cold temperatures.
100
What skin change may occur after cold panniculitis?
Mild subcutaneous atrophy (dimpling) due to adipocyte apoptosis from cold temperature.
101
What is a common treatment approach for cold panniculitis?
Reassurance and supportive analgesia as necessary.
102
What is the effect of an ice cube challenge on the skin?
It can lead to the development of an erythematous subcutaneous plaque 12 to 18 hours later.
103
What is the typical time frame for lesions from cold panniculitis to subside?
Lesions typically subside spontaneously within 2 to 3 weeks.
104
Why do infants have a higher risk of solidification at less-cold temperatures?
They have a higher content of saturated fatty acids in adipose tissue than adults.
105
Scenario: A patient develops erythematous subcutaneous plaques 12 hours after an ice cube challenge. What condition does this confirm, and what is the typical prognosis?
This confirms Cold Panniculitis. The typical prognosis is spontaneous resolution within 2 to 3 weeks.
