Causalgia Following Gunshot Injuries of Nerves : Role of Emotional Stimuli and Surgical Cure through Interruption of Diencephalic Efferent Discharge by Sympathectomy

Defining the therapeutic role of local anesthetic sympathetic blockade in complex regional pain syndrome: a narrative and systematic review

OBJECTIVE

There is growing controversy on the value of blocking the sympathetic nervous system for the treatment of complex regional pain syndromes (CRPS). The authors sought to evaluate the efficacy of sympathetic blockade with local anesthetic in these syndromes. In addition, they performed a comprehensive review of the pathophysiology and other treatments for CRPS.

DESIGN

Systematic review of the literature was performed. MEDLINE was searched from 1966 through 1999. The authors identified only three randomized controlled trials (RCTs) that evaluated sympathetic blockade with local anesthetic, but because of differences in study design they were unable to pool the study data. The authors therefore included nonrandomized studies and case series.

INTERVENTIONS

Studies were included if local anesthetic sympathetic blockade was used in at least 10 patients. Studies were excluded if continuous infusion techniques, somatic nerve blocks, or combined sympatholytic therapies were evaluated.

OUTCOME MEASURES

Pain relief was classified as full, partial, or absent. The lack of a comparison group in the studies allowed only the calculation of distribution of the response categories, and the sum of the pooled rates does not equal 100%.

RESULTS

Twenty-nine studies were included that evaluated 1,144 patients. Nineteen studies were retrospective, 5 prospective case series, 3 RCTs, and 2 nonrandomized controlled studies. The quality of the publications was generally poor. Twenty-nine percent of patients had full response, 41% had partial response, and 32% had absent response. It was not possible to estimate the duration of pain relief.

CONCLUSIONS

This review raises questions as to the efficacy of local anesthetic sympathetic blockade as treatment of CRPS. Its efficacy is based mainly on case series. Less than one third of patients obtained full pain relief. The absence of control groups in case series leads to an overestimation of the treatment response that can explain the findings.

Sympathectomy for causalgia: experience with military injuries

BACKGROUND

Causalgia is a rare disease in civilian practice, and most reports regarding causalgia in the literature are from major extended wars. To increase awareness of this syndrome, our wartime experience with this disease is presented.

METHODS

The charts of patients with causalgia referred to two university hospitals for treatment from 1985 to 1989 were retrospectively studied. Characteristics of the cause, clinical manifestations, and the response to therapy were evaluated.

RESULTS

Among 1,564 patients with peripheral nerve injuries, there were 54 cases (3.4%) of causalgia. All of the patients, except five, were injured in battle by high-velocity bullets or missiles. Upper extremities were involved in 28 patients (52 %) and lower extremities in 26 patients (48%). The most common presenting symptoms were as follows: burning pain, 100%; wet extremity, 100%; cold extremity, 93%; sensitivity to cold, 89%; paresthesia, 78%; and color changes in the extremities, 55%. In 48 patients (89%), pain was relieved by sympathetic block (3 patients had permanent cure). Six patients had no response to the blocks (11%). Of 45 patients who had temporary relief, all underwent sympathectomy. All of these patients had complete relief of symptoms in the immediate postoperative period and for follow-up from 1 to 6 years.

CONCLUSION

Causalgia is essentially a war casualty disease. The condition is associated with burning pain, hyperesthesia, and symptoms of sympathetic overactivity. Sympathectomy is effective and the treatment of choice, particularly for patients who respond temporarily to sympathetic blocks.

Bilateral burning foot pain: monitoring of pain, sensation, and autonomic function during successful treatment with sympathetic blockade

We describe a patient with burning pain in both feet associated with local autonomic disturbances following bilateral traumatic sciatic mononeuropathies. The diagnosis of a sympathetically maintained pain was confirmed through a prompt response to sympathetic blockade. Although a mild alcohol-nutritional neuropathy was found, the clinical findings strongly suggested a diagnosis of bilateral causalgia. Clinical evaluation and quantitative sensory testing were performed prior to and after successive unilateral lumbar sympathetic nerve blocks. After unilateral blockade, bilateral improvement was recorded in measures of pain, sudomotor function, and foot temperature. Other measures of autonomic function showed variable responses to sympathetic blockade. Quantitative sensory testing revealed a dramatic alteration in the contralateral limb's thermal sense following unilateral block. This case underscores the potential for bilateral causalgia and provides additional evidence for a central mechanism operating in this disorder. The relationship between bilateral causalgia and the "burning feet syndrome" in alcoholic neuropathy is discussed.

Management of causalgia after peripheral nerve injury

The authors report on a series of patients with severely painful disorders of peripheral nerves--they review the modern theories on the nature of causalgia and reflex sympathetic dystrophy. Peripheral causes include spontaneous discharges from neuroma sprouts, their sensitivity to adrenergic compounds, ectopic generator activity in abnormally myelinated fires and increased firing in dorsal root ganglia. Central causes include spontaneous activity of deafferented nerves in the dorsal horn and development of response to new receptive fields. The natural history of such disorders is poor--many patients suffering pain for 10 years or more--the clinical picture is characterized by spontaneous burning pain and allodynia and hyperpathia, chronicity, osteoporosis, skin and nail changes and deformities. The basis of treatment is sympathetic blockade using intravenous guanethedine on alternate days. At least 6 blocks are given as the majority of patients do not respond until the 5th or 6th block. Each block is followed by desensitization and intensive rehabilitation. The authors emphasize that sympathetic blockade is only one, albeit the most important, modality in a multi-faceted treatment programme. Surgical attempts to relieve pain almost uniformly failed--causing as they do further neuronal changes peripherally and centrally. Recurrences depend on the degree of initial response. Those who obtained virtually complete relief of pain had a lower recurrence rate but a high proportion needed repeated sessions of treatment at yearly intervals. Follow-ups must therefore be indefinite.

Phenoxybenzamine in the treatment of causalgia. Report of 40 cases

Forty consecutive cases of causalgia treated during a 7-year period are presented. The patients ranged in age between 17 and 55 years, and all patients were males who received their nerve injuries from missile or shrapnel wounds. The greater occipital nerve was involved in two cases, median nerve in 10, sciatic nerve in 12, brachial plexus in seven, cauda equina in five, and multiple nerves in four cases. Each patient was treated with phenoxybenzamine, a postsynaptic alpha 1-blocker and presynaptic alpha 2-blocking agent. The drug was given orally in gradually increasing increments until a maximum daily dose of 40 to 120 mg was reached. Duration of treatment was usually 6 to 8 weeks. Total resolution of pain was achieved in all cases. The follow-up period ranged between 6 months and 6 years. Side effects of phenoxybenzamine were minimal and transient, consisting primarily of mild orthostatic hypotension and ejaculatory problems. We conclude that oral phenoxybenzamine is a simple, safe, and effective treatment of causalgia.

Causalgia: redefinition as a clinical pain syndrome

In this report, the following criteria were used for the diagnosis of causalgia: (a) the presence of continuous, burning pain distal to a site of injury; (b) hyperalgesia and allodynia in the painful area; and (c) a traumatic event occurring proximal in the painful area and within weeks prior to the onset of pain. The McGill pain questionnaire was used to test the selected pain population for homogeneity. The scores were similar among the patients and different from the scores in other pain syndromes. It is concluded that the above criteria are sufficient to make the diagnosis of causalgia. In addition, it appears that a central nervous system abnormality best accounts for the clinical features of causalgia.