• Post-Injury Care

Authors: Malcolm Davidson, Alex Poole, Caitlin Champion

Frostbite Wound Care

In the weeks that follow initial acute treatment of frostbite injury, care is focused on avoiding complications, such as infection, and supporting wound healing. Low grade (1-2) injuries are expected to heal with topical therapy and water cleansing alone. Higher grade frostbite injuries are at greater risk of complications and thus should be more closely monitored. Amputation and/or debridement of tissue in grade 3-4 frostbite is often required, and early consultation with surgery should occur for wound care follow-up and surgical planning. Management of wound care in frostbite is limited in evidence, restricted to case series and reports. Principles for on-going management of frostbite wounds are extrapolated from the management of wounds in other contexts. See Frostbite Care Protocols and Guidelines section for specific references.

Assessing evolution of tissue damage

Severe frostbite injuries evolve in appearance over several weeks as eschar forms and the tissue demarcates. Wounds should be monitored closely for infection and progression of necrosis over the first two weeks and then weekly up to three to four weeks.

Dressings

Dressing material should be low adhesive material, such as paraffin gauze or similar. Dry, bulky gauze is recommended for protection. As significant edema can occur, circumferential dressings should be wrapped loosely. Daily dressing changes are recommended for the first week, and subsequently every 3-4 days for several weeks as the wound evolves, with topical aloe vera applied at every dressing change (2,3).

Hydrotherapy

Frostbitten areas should undergo immersion in warm water to allow for removal of debris, cleaning of affected tissue, and facilitating mobility of the joint. Following immersion, the area is to dry by air or pat drying. It is strongly advised to avoid rubbing the affected tissue while cleaning or drying to avoid further skin injury. The frequency and duration of wound cleansing is to be advised by the patient’s care team, informed by the evolution of the wound. As eschar develops, wounds are best kept clean, dry and bandaged.

Infection

Monitor daily for the development of signs and symptoms of infection including odor, purulent drainage, wet or boggy discoloured tissue.

Blisters

Inflammatory mediators such as thromboxane and prostaglandins present in the serous exudate may lead to further tissue damage if not removed. Significant clear serum blisters should be aspirated or debrided on initial presentation. Hemorrhagic blisters should not undergo aspiration or debridement initially, as they indicate deep tissue or vessel injury, and may respond positively to systemic treatment. Over the first week of care, hemorrhagic blisters will often evolve; those that rupture spontaneously can be debrided, those that persist beyond 1 week may be aspirated if they are articulating with the joint or impeding range of motion rehabilitation

Topical therapy

Aloe vera may limit the release of thromboxane and can be applied to the wound for at least the first five days of injury approximately every six hours, with subsequent aloe vera application at every dressing change recommended (20).

Mobilization

To minimize edema, it is recommended to elevate affected limbs. A trial investigated outcomes of severe frostbite patients with early mobilization of affected limbs (<72 hours from injury) versus extended immobilization for longer than this duration. They found no significant differences between the groups with respect to tissue loss and complications, suggesting that early mobilization may not have an impact on frostbite outcomes (35). However, in cases of severe frostbite where the affected limb is insensate, caution in mobilization is required as to not cause further injury. Appropriate well-fitting footwear and custom orthotics are recommended to optimize function if the lower extremities are affected, and involvement of a multidisciplinary rehabilitation team (i.e. - Physiotherapy, Occupational Therapy, Nursing Wound Specialists, Social Workers, etc.) may improve functional outcomes (20).

Surgical Intervention in Frostbite

The goal of surgical intervention is to support optimal function of the remaining limb, preserving tissue where possible and managing infection when it occurs. Patients should be monitored for signs of infection, and grade the severity of the wound daily for the first two weeks, and then weekly thereafter for three to four weeks. Mild frostbite (grade 1) is expected to heal with observation, whereas higher grades often require surgical intervention. Severe frostbite injuries evolve in appearance over several weeks as eschar forms and the viable and non-viable tissue demarcates. Amputation is often delayed several months to allow for clear demarcation to maximize preservation of viable tissue, the extent of which may be less clear initially. The exception to this is if the patient develops signs of infection, such as wet gangrene, or symptoms of sepsis attributable to infected frostbite tissue, at which point debridement, or amputation, should be performed urgently (36). During the waiting period, the affected tissue is often insensate due to extensive nerve damage in the acute phase of the injury, and pain is not present in the affected tissue.

Bone scintigraphy and SPECT/CT may be used to assess the extent of tissue injury in the first week of frostbite injury and guide management (26,30). In cases where the amount of tissue loss would be detrimental to function, such as loss of total thumb, multiple digits, or extensive hand involvement, early bone scans demonstrating no or very little uptake may undergo aggressive debridement and surgical salvage before the development of dry eschar (37).

Following surgical intervention of severe frostbite injury, there remains a significant risk of complications that may require further intervention. Coward et al. found that approximately one quarter of patients who underwent primary amputation for frostbite injury required a revision surgery within three years, including either debridement or reamputation of tissue. Further, they found a significant proportion of these patients having soft or deep tissue infections at the time of requiring revision surgery. It is not yet clear whether these revisions were a result of original surgical planning (i.e. appropriate timing or extent of surgical intervention), or long-term sequelae of tissue injury. Notably, 88% of the study population had high risk social factors that may have influenced surgical complications post-surgery.

Imaging in Frostbite Follow-Up Care

In the sub-acute to chronic stages of frostbite injury, limited use and evidence exists for the utility of imaging.

Radiography

X-Ray may be useful weeks to months following a deep frostbite wound to demonstrate bony changes such as erosions, periostitis, or epiphyseal injury in children (38,39). Findings typical of osteoarthritis, such as joint space narrowing, may be present in patients with frostbite arthropathy (40). 

Long-term Complications of Frostbite Injury

Long-term chronic complications of frostbite are a consequence of microvascular injury and subsequent dysfunction. Once tissue healing has occurred, vasospasm and poor vascular perfusion lead to complications such as cold hypersensitivity of the affected areas, numbness, loss of function or neuropathic chronic pain (5). Future wound healing issues including osteomyelitis, tissue infection, and skin ulceration are also more common in the affected regions due to poor vascular supply (6-10). Lastly, frostbite arthropathy is an important late complication of frostbite. Appearing clinically similar to osteoarthritis, frostbite arthropathy presents with chronic pain and loss of joint function, with imaging findings demonstrating bony remodeling and joint space abnormalities (5). Management of sequelae of chronic frostbite involves pain control, optimizing function, and preventing re-injury. Early involvement of a multidisciplinary rehabilitation team (i.e. - Physiotherapy, Occupational Therapy, Nursing Wound Specialists, Social Workers, etc.) produces better long-term functional results (20).

Chronic regional pain is perhaps the most common complaint post-frostbite. The pain is often unresponsive to conventional analgesia and may be lifelong. Neuropathic analgesics such as duloxetine, amitriptyline and gabapentinoids may provide benefit. Topical agents such as capsaicin or lidocaine may also be used. A referral to a chronic pain specialist is recommended if available. Cold hypersensitivity is a long-term consequence of frostbite that may be debilitating for patients, due to inappropriate vasoconstriction of the vasculature. There is low-level evidence that botulinum toxin A, a medicine that works to inhibit vasoconstriction of smooth muscle, may alleviate cold hypersensitivity and sensory-motor disturbances in frostbite (41).

Preventing Re-Injury

There is a high risk of re-injury in frostbite. Caution should be taken to avoid additional injury in digits and limbs for severe frostbite, as the digit is often insensate. Appropriate footwear and orthotics are highly recommended to avoid pressure injury and patients should take extreme caution in cold weather conditions, always including weather appropriate clothing, and the use of warming pads.

Social considerations in post-hospital frostbite care

Social circumstances may present a significant challenge in the on-going management of frostbite care. Risk factors for the first presentation of frostbite in urban settings include homelessness and substance use disorders (42,43).  Accessibility of frequent long-term follow up care may be less feasible for patients with challenging social situations.  Substance use disorders or other psychiatric disorder diagnoses, and insecure living situations are significant risk factors for readmission to hospital for frostbite related injury (9,44). Accounting for this, providers should consider a patient’s social circumstances when formulating a long-term follow up plan to ensure continuity of care after discharge. Secondary prevention of frostbite includes the provision of accessible emergency shelter and drop-in warming services, which can greatly reduce frostbite readmissions and morbidity in the urban frostbite population (43).