Trench foot is one of three subclasses of immersion foot and is considered a non-freezing cold injury (NFCI). It is often differentiated by the temperature of the exposure and is caused by prolonged exposure to cold but usually not freezing, damp, and sometimes unsanitary conditions. The condition will ultimately cause skin and tissue breakdown which increases the risk of infection and raises morbidity and mortality.[rx][rx][rx]
Pathophysiology
Unlike frostbite, trench foot can occur without freezing temperatures. The feet can be affected in temperatures up to 16 C (60 F), and the disease can develop in as little as 10 to 14 hours.[rx] With the addition of moisture to the above environmental conditions, destruction and deterioration of the capillaries can lead to degradation of the surrounding tissue. The pathophysiology is thought to be due to varying vasoconstriction and vasodilation resulting in local tissue damage.[rx] Hyperhidrosis (excessive sweating) can also be a contributing factor to the development of trench foot.
Causes of Trench Foot
Many soldiers during World War I had trench foot. Starting in 1914, trench warfare was a common strategy on the European front. During this time, the soldiers found themselves standing in waterlogged trenches at the front for long periods of time and were subjected to wet, cold, and muddy conditions. In the winter between 1914 and 1915, it is reported that over 20,000 British troops were treated for trench foot. Furthermore, it is estimated that trench foot contributed to the deaths of 2000 Americans and roughly 75,000 British soldiers. Interestingly, trench foot was first described in 1812 while Napoleon’s army was retreating from Russia. Dr. Dominique Jean Larrey, a French army surgeon, was the first clinician to describe the condition. Although the prevention of trench foot is relatively straightforward and widely known, as recently as 1982, the British Army dealt with the condition during the Falklands War.[rx][rx][rx]
Unlike frostbite, trench foot does not require freezing temperatures; it can occur in temperatures up to 16 °C (61 °F) and within as little as 13 hours. Exposure to these environmental conditions causes deterioration and destruction of the capillaries and leads to the morbidity of the surrounding flesh.[rx] Excessive sweating (hyperhidrosis) has long been regarded as a contributory cause; unsanitary, cold, and wet conditions can also cause trench foot.[rx]
Symptoms of Trench Foot
Affected feet may become
- numb, by erythema (turning red) or cyanosis (turning blue), as a result of poor blood supply, and may begin emanating a decaying odor if the early stages of necrosis (tissue death) set in.
- As the condition worsens, feet may also begin to swell. Advanced trench foot often involves blisters and open sores, which lead to fungal infections; this is sometimes called tropical ulcer (jungle rot). If left untreated, trench foot usually results in gangrene, which may require amputation. If trench foot is treated properly, complete recovery is normal, although it is marked by severe short-term pain when feeling returns.[rx]
-
- blisters
- blotchy skin
- redness
- skin tissue that dies and falls off
Additionally, trench foot can cause the following sensations in the feet:
- coldness
- heaviness
- numbness
- pain when exposed to heat
- persistent itching
- prickliness
- tingling
Affected feet may become numb, by erythema (turning red) or cyanosis (turning blue), as a result of poor blood supply, and may begin emanating a decaying odor if the early stages of necrosis (tissue death) set in. As the condition worsens, feet may also begin to swell. Advanced trench foot often involves blisters and open sores, which lead to fungal infections; this is sometimes called tropical ulcer (jungle rot).
Diagnosis of Trench Foot
History and Physical
Trench foot often begins with a tingling, itching that can progress to numbness. In the setting of cold exposure, vascular changes resulting in poor blood flow can result in the feet becoming erythematous or cyanotic. In later stages, as the extremity is rewarmed hyperesthesia is often noted.[rx] With prolonged exposure and poor care, they may have an odor of decay if necrosis has started to set in. Significant swelling can occur, and there are some descriptions that the feet can double in size due to the edema. The disease has been known to commonly affect the heels or toes but can extend above the foot. The skin can appear blotchy, and as the disease progresses, blisters and open sores can occur which can lead to fungal as well as bacterial infections. As the disease continues to advance, skin and tissue may slough off. If the condition is left untreated, gangrene can set in. At this point, amputation may be needed to avoid further progression of the disease and other complications such as sepsis and death. When trench foot is identified and treated early, complete recovery is expected; although, there can be a significant amount of temporary pain when sensation returns to the affected area
Evaluation
The diagnosis of trench foot is entirely clinical. One must first identify the situations where it occurs, and a good physical examination is paramount. Underlying infections must be ruled out so a white blood cell count might be indicated. Inflammatory markers such as a C-reactive protein (CRP) or erythrocyte sedimentation rate might prove helpful, as will a radiograph or bone scan if underlying osteomyelitis is suspected.
Treatment of Trench Foot
The mainstay of treatment, like the treatment of gangrene, is surgical debridement, and often includes amputation. Self-treatment consists of changing socks two or three times a day and usage of plenty of talcum powder. Whenever possible, shoes and socks should be taken off, the feet bathed for five minutes and patted dry, talcum powder applied, and feet elevated to let air get to them.
The best treatment for trench foot is prevention. Some of these methods are outlined above. It was critical that soldiers changed their socks frequently and made sure their feet were dry to avoid the condition. During World War I, as the understanding of the disease progressed, the treatment of trench foot also evolved. Early on, bed rest was recommended, and the application of numerous different agents was tried at one time or another. Among these included a mixture of lead and opium, alcohol of different types, mercuric chloride in alcohol, tincture of iodine, oil of wintergreen, picric acid, and chloral hydrate mixed with camphor. Some powders were also used including boric acid, starch, zinc, and salicylic acid. Radiant heat, complex methods of massage, and even different types of electrical stimulation were tried in treating trench foot when the initial treatments failed. However, once the disease progressed to a severe case, the mainstay of treatment was surgical, similar to the treatment of gangrene. Many times, the patient ended up with an amputation.[rx]
Current treatment recommendations are with slow passive rewarming of the affected extremity with adequate pain control with amitryptiline or other modalities for neuropathic pain.[rx][rx] It is important to assess for signs of hypothermia and to remove the affected extremity from any inciting environmental causes.
Complications
Complications and uncommon and typically the result of inappropriate care. Soft tissue skin infections such as cellulitis or gangrene are possible in later stages of presentation and should be managed with appropriate antibiotics or antifungal treatments. Subacute or chronic neuropathic pain is more common and can be managed with various modalities to treat neuropathic pain.[rx] In rare circumstances and if not managed/treated appropriately permanent sensory changes may be seen and or amputation may be required.
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