The immersion foot syndrome. 1946.

1. Prolonged exposure of the extremities to cold insufficient to cause tissue freezing produces a well-defined syndrome. 'Immersion foot' is one of the descriptive but inaccurate terms applied to this syndrome. The clinical features, aetiology, pathology, prevention, and treatment of immersion foot are considered in detail. A discussion on pathogenesis is also included. 2. In the natural history of a typical case of immersion foot there are four stages: the period of exposure and the pre-hyperaemic, hyperaemic, and post-hyperaemic stages. 3. During exposure and immediately after rescue the feet are cold, numb, swollen, and pulseless. Intense vasoconstriction sufficient to arrest blood-flow is believed to be the predominant factor during this phase. 4. This is followed by a period of intense hyperaemia, increased swelling, and severe pain. Hyperaemia is due to the release in chilled and ischaemic tissues of relatively stable vasodilator metabolites; pain may be the result of relative anoxia of sensory nerve-endings. 5. Within 7-10 days of rescue the intense hyperaemia and swelling subside and pain diminishes in intensity. A lesser degree of hyperaemia may persist for several weeks. Objective disturbances of sensation and sweating and muscular atrophy and paralysis now become apparent. These findings are correlated with damage to the peripheral nerves. 6. After several weeks the feet become cold-sensitive; when exposed to low temperature they cool abnormally and may remain cold for several hours. Hyperhidrosis frequently accompanies this cold-sensitivity. The factors responsible for these phenomena are incompletely understood; several possible explanations are considered. 7. Severe cases may develop blisters and gangrene. The latter is usually superficial and massive loss of tissue is rare. 8. The hands may be affected but seldom as severely as the feet. The essential features of immersion hand are the same as those of immersion foot. 9. Prognosis depends upon severity. The extent of anaesthesia at 7-10 days has been found a useful guide to the latter, and has formed a basis of a method of classification. 10. Rapid warming of chilled tissues is condemned. Cold therapy is of value for the relief of pain in the hyperaemic stage, but should not be used in the pre-hyperaemic stage. Sympathectomy and other measures designed to increase the peripheral circulation should not be employed immediately after rescue, but may have a place in the treatment of the later cold-sensitive state. This paper records the results of observations made during 1941 and 1942. Delay in publication has been necessary because of war-time difficulties of maintaining contact between authors. In this respect we have received much help from Surgeon Rear-Admiral J. W. McNee. We wish to thank Professors R. S. Aitken and J. R. Learmonth for much helpful advice during the preparation of the paper. The charts have been prepared by the technical staff of the Wilkie Surgical Research Laboratory, University of Edinburgh. During the period of the study, one of us (R. L. R.) was in receipt of a personal grant from the Medical Research Council.

Replantation of an avulsive amputation of a foot after recovering the foot from the sea.

A foot avulsion case, with the dismembered body part submerged in sea water for 1 hour, is presented. This report is unique in that it is the first to document the reattachment of a body part that had been submerged in sea water. It was not known how salt-water exposure would affect wound management. Differences in osmolarity and bacterial flora between the sea water and foot tissues have not caused any problems, and the patient has not suffered any vascular or infectious complications after replantation. Neurotization of the plantar surface by the tibial nerve, which was stripped off during amputation and replaced in its original traces, was the most critical part of convalescence. After management of such an interesting case, we conclude that exposure to sea water of the dismembered part should not be a contraindication for replantation surgery.

Nerve conduction studies in experimental non-freezing cold injury: II. Generalized nerve cooling by limb immersion.

After immersion of the hind limb of the rabbit, up to the lower thigh, in a waterbath, at 1 degree C for 10 to 14 hours under light anesthesia, there was evidence of persistent nerve damage to the tibial nerve, which varied in severity in different animals. Nerve conduction studies, carried out within 24 hours of removal from the bath, showed that in a proportion of the motor and/or afferent fibers, there was conduction failure between the knee and ankle. This was followed, over the next 48 hours, by distal degeneration of the affected fibers. No persistent conduction block was seen. After distal degeneration had occurred, maximal conduction velocity was mildly reduced, suggesting that the fastest-conducting motor and afferent fibers had been particularly affected. Morphological studies confirmed preferential large myelinated fiber degeneration, the earliest lesions being seen in the leg at the level of the upper calf. Limb edema was not seen after cooling, and there was no histological evidence of muscle necrosis or damage to blood vessels. No abnormalities were seen in 4 control animals after hind limb immersion for 12 hours at temperatures of 30 to 35 degrees C. Possible reasons for the proximal site of myelinated nerve fiber damage during hindlimb cooling are discussed.

Trench foot--a study in military-medical responsiveness in the Great War, 1914-1918.

Along the nearly 15,000 miles of trenches on the western front in the Great War of 1914-1918, a condition known as "trench foot" caused serious attrition among the fighting troops and resulted in swollen limbs, impaired sensory nerves, inflammation, and even loss of tissue through gangrene. Physicians, sanitarians, and military officers explored numerous theories regarding etiology and treatment before focusing on a combined regimen of common-sense hygiene and strict military discipline.

Infrared thermographic measurement of circulatory compromise in trenchfoot-injured Argentine soldiers.

Passive rewarming of a cold-water stressed foot was evaluated in 33 recovered trenchfoot (TF) patients and 15 uninjured men. Infrared images were recorded prior to immersion, immediately following, and at 1-min intervals for 20 min. Individual baseline temperature (IBT) recovery was used to separate subjects into three groups designated Good and Poor Rewarming Controls (GRC and PRC) and Injured Subjects (Inj Sub). IBTs were significantly less (p less than 0.01) for Inj Sub compared to both GRC and PRC while no difference existed between GRC and PRC. This relationship changed when slopes of and areas under the mean rewarming curves were compared. Both these criteria were significantly greater (p less than 0.01) for GRC than for PRC and Inj Sub, while no difference was noted between PRC and Inj Sub. It could not be determined if the poor response of Inj Sub was inherent or a result of injury. We conclude that previously injured subjects and nearly 60% of a normal population may be at significant risk for cold injury.

Epidural and spinal anesthesia do not influence gastric emptying and small intestinal transit in volunteers.

The influence of thoracic epidural anesthesia, spinal anesthesia, and a painful stimulus on gastric emptying, orocecal transit time, and small intestinal transit were studied in nine healthy volunteers. Gastric emptying was measured by the acetaminophen absorption method. Orocecal transit time was determined by measuring end-expiratory hydrogen concentration. Small intestinal transit was calculated from measurements of the orocecal transit time and gastric emptying. Cold pain stress with intermittent immersion of the feet in ice-cold water was used as a painful stimulus. Each volunteer was investigated on four occasions: 1. during nociceptive stimulation of the feet (cold pain); 2. during low spinal anesthesia with block of the afferent nerves from the nociceptive stimulated area; 3. during thoracic epidural anesthesia (0.5% bupivacaine) with block of the efferent nerves to the stomach and small intestine but with intact afferents from the nociceptive stimulated area; 4. as a control study without pain and anesthesia. Without spinal anesthesia, immersion of the feet in cold water was very painful and caused a circulatory stress reaction with increased blood pressure. Cold pain stress in itself did not influence gastric emptying, orocecal transit time, or small intestinal transit. Neither did epidural or spinal anesthesia during cold pain stress influence these variables of gastrointestinal motility. Thus, low spinal anesthesia or thoracic epidural anesthesia in itself did not influence gastric emptying, orocecal transit, or small intestinal transit.

Cold-induced peripheral nerve damage: involvement of touch receptors of the foot.

A 31-year-old male developed paresthesia and numbness of mainly the right foot following exposure to nonfreezing temperatures under moist conditions over a period of 1 week. The symptoms gradually improved over several months. When seen for electrophysiological studies 6 months after the injury, there was no sensory loss on clinical examination, although he continued to complain of distal numbness of the right foot. The right extensor digitorum brevis muscle was atrophic, and the distal motor latency in the peroneal nerve was prolonged. Conduction studies of the right sural nerve showed a predominantly distal diminution of the SAP evoked by electrical stimulation at the dorsum pedis. Action potentials evoked by tactile stimulation of Pacinian corpuscles showed a prolonged latency on the symptomatic side, suggesting that the most pronounced pathological changes in immersion injury may be localized to the very distal portion of the nerve at the nerve fiber-receptor junction.