Changes

Severe frostbite is a grave physiological condition with potentially '''life-threatening consequences'''.

Severe frostbite is a grave physiological condition with potentially '''life-threatening consequences'''.

All species are susceptible, but '''neonates''' are at greatest risk due to thin skin and lack of subcutaneous fat stores. Avian species endogenous to warm climates but kept in temperate areas are most susceptible to frostbite.

All species are susceptible, but '''neonates''' are at greatest risk due to thin skin and lack of subcutaneous fat stores. Avian species endogenous to warm climates but kept in temperate areas are very susceptible to frostbite.

Frostbite may be '''primary or secondary to an underlying disease''' which compromises the animal's resistance to cold. For instance sick calves may suffer from the condition despite adequate housing and nutrition.

Frostbite may be '''primary or secondary to an underlying disease''' which compromises the animal's resistance to cold. For instance sick calves may suffer from the condition despite adequate housing and nutrition.

Tissue damage is substantially increased if thawing is followed by refreezing (freeze-thaw-freeze-thaw syndrome). Tissue previously damaged by freezing is more susceptible to injury on subsequent exposure to cold temperatures.

Tissue damage is substantially increased if thawing is followed by refreezing (freeze-thaw-freeze-thaw syndrome). Tissue previously damaged by freezing is more susceptible to injury on subsequent exposure to cold temperatures.

==Pathphysiology==

==Pathophysiology==

The four phases describing the mechanism of cellular injury are:

The four phases describing the mechanism of cellular injury are:

Direct cellular destruction, release of catecholamines and tissue anoxia have potentially significant secondary effects in severe frostbite cases, resulting in '''damage to other organs'''.

Direct cellular destruction, release of catecholamines and tissue anoxia have potentially significant secondary effects in severe frostbite cases, resulting in '''damage to other organs'''.

==Clinical signs==

==Clinical Signs==

'''Mild frostbite''' causes blanching of tissue and reduced sensation followed by painful erythema, scaling and alopecia.

'''Mild frostbite''' causes blanching of tissue and reduced sensation followed by painful erythema, scaling and alopecia.

This is based on the history and the appearance of the skin and tissue on the affected area.

This is based on the history and the appearance of the skin and tissue on the affected area.

'''Differential diagnoses''' include: traumatic injury, tissue damage from ergot toxicosis.

'''Differential diagnoses''' include: traumatic injury, tissue damage from ergot toxicosis in mammals.

To avoid frostbite, long-legged birds reduce peripheral circulation to their limbs, which can result in skin lesions such as cracking and low-grade bacterial infections.

To avoid frostbite, long-legged birds reduce peripheral circulation to their limbs, which can result in skin lesions such as cracking and low-grade bacterial infections.

'''Trauma and self-mutilation''' is prevented if possible, but bandaging of the areas is not recommended.

'''Trauma and self-mutilation''' is prevented if possible, but bandaging of the areas is not recommended.

Conservative treatment is indicated until there is clear demarcation of viable and non-viable tissue, unless infection develops.

Conservative treatment is indicated until there is clear demarcation of viable and non-viable tissue, unless infection develops. Dry gangrene and sloughing then follow.

 

Dry gangrene and sloughing develop.

'''Systemic anti-inflammatories''' and topical agents such as '''aloe vera''' creams have been found to reduce the amount of tissue loss and the length of hospitalisation in small animals.

'''Systemic anti-inflammatories''' and topical agents such as '''aloe vera''' creams have been found to reduce the amount of tissue loss and the length of hospitalisation in small animals.

Radiostits, O. (2000) '''Veterinary clinical examination and diagnosis''' ''Elsevier Health Sciences''

Radiostits, O. (2000) '''Veterinary clinical examination and diagnosis''' ''Elsevier Health Sciences''

[[Category:Integumentary System - Physical Damage]]

[[Category:Integumentary System - Physical Damage]]