Mechanisms other than shunting are likely contributing to the pathophysiology of erythromelalgia

Thalamic stimulation as a treatment for primary erythromelalgia: technical case report

OBJECTIVE AND IMPORTANCE

We report the use of bilateral thalamic stimulation in a case of primary erythromelalgia with immediate and important pain relief for 3 years.

CLINICAL PRESENTATION

A 12-year-old boy experiencing primary erythromelalgia had a 4-year history of recurrent attacks of severe burning pain in both feet, accompanied by local reddening, swelling, and heating of the skin. The attacks were triggered by warmth and exercise. The pain was relieved only by elevation and cooling of the lower limbs, which he achieved by immersing his legs in a bucket of ice water, resulting in severe ulceration of the skin.

INTERVENTION

Because of the gradual aggravation of the signs and symptoms and resistance of the patient's condition to several medical therapies, the patient received spinal cord stimulation. The implants were removed twice because of recurrent infection. Finally, the patient was treated with bilateral electrical stimulation of the ventral posterolateral thalamic nucleus, which resulted in important pain control until 3 years later. The patient was able to avoid water immersions, and all ulcerations disappeared.

CONCLUSION

We conclude that thalamic stimulation was successful in this case of primary erythromelalgia.

Erythromelalgia

No treatment is consistently effective in the management of patients with erythromelalgia. There is a dearth of adequate studies examining the response of erythromelalgia to treatment. Most recommendations are suggested based on case reports, small case series, and anecdotal reports. The management of erythromelalgia is difficult and frequently involves a multidisciplinary approach. An approach to management of individuals with erythromelalgia includes patient education, learning to avoid episodes, relieving discomfort of the episodes, controlling secondary and underlying factors, and use of drugs used to control erythromelalgia.

Pain in primary erythromelalgia—a neuropathic component?

Erythromelalgia is a condition characterized by attacks of red, hot, painful extremities with relief of symptoms by cooling and aggravation by warmth. Although the main emphasis has been on pathophysiological mechanisms related to circulatory changes, recent reports have focused on an involvement of efferent small nerve fibers indicating a neuropathic component. Since the symptoms resemble those described in neuropathic pain, we wanted to investigate the possible affection of afferent nerve fibers. Twenty-five patients with primary erythromelalgia were examined by neurological testing, neurography and quantitative sensory testing. Thresholds for heat, cold, heat-pain and cold-pain detection were compared with those of a group of 29 healthy controls. The patients had significantly higher median heat (39.5 (36.1-40.8) and cold (29.3 (27.1-30.8)-detection thresholds at the dorsal aspects of their feet compared to the controls (37.0 (35.4-37.7) and 31.2 (30.3-31.5) respectively). These findings show an impaired small fiber function inside or close to the symptomatic area in this group of erythromelalgia patients. Seven patients had brush-evoked allodynia and fourteen had punctate hyperalgesia inside or close to the symptomatic areas in their feet. When comparing the individual results, there is a tendency to clustering of patients in two separate groups; reduced small fiber input/no hyperalgesia and normal thermal thresholds/hyperalgesia. Our results showing an affection of afferent small nerve fibers together with the nature of the symptoms, suggest that the pain experienced by erythromelalgia patients could have a neuropathic component.

Coexistence of erythromelalgia and Raynaud's phenomenon

Erythromelalgia is characterized by spontaneous recurrent episodes of redness, heat, and pain of the extremities that can be triggered or worsened by heat. Raynaud's phenomenon occurs in response to cold exposure and presents as pallor of the fingers or toes, often followed by cyanosis and rubor. Although the 2 conditions may appear to be opposites in symptomatology and clinical presentation, there are very rare reports of their coexistence. A case of coexistent erythromelalgia and Raynaud's phenomenon is presented. The pathophysiology is reviewed to elucidate a common mechanism underlying some cases of the 2 seemingly opposite conditions. A review of the literature indicates that causative and pathophysiologic similarities between the 2 conditions may exist in some cases. Rare reports of coexistence of the 2 disease processes further strengthen such research findings.

Skin blood flow in adult human thermoregulation: how it works, when it does not, and why

The thermoregulatory control of human skin blood flow is vital to the maintenance of normal body temperatures during challenges to thermal homeostasis. Sympathetic neural control of skin blood flow includes the noradrenergic vasoconstrictor system and a sympathetic active vasodilator system, the latter of which is responsible for 80% to 90% of the substantial cutaneous vasodilation that occurs with whole body heat stress. With body heating, the magnitude of skin vasodilation is striking: skin blood flow can reach 6 to 8 L/min during hyperthermia. Cutaneous sympathetic vasoconstrictor and vasodilator systems also participate in baroreflex control of blood pressure; this is particularly important during heat stress, when such a large percentage of cardiac output is directed to the skin. Local thermal control of cutaneous blood vessels also contributes importantly--local warming of the skin can cause maximal vasodilation in healthy humans and includes roles for both local sensory nerves and nitric oxide. Local cooling of the skin can decrease skin blood flow to minimal levels. During menopause, changes in reproductive hormone levels substantially alter thermoregulatory control of skin blood flow. This altered control might contribute to the occurrence of hot flashes. In type 2 diabetes mellitus, the ability of skin blood vessels to dilate is impaired. This impaired vasodilation likely contributes to the increased risk of heat illness in this patient population during exposure to elevated ambient temperatures. Raynaud phenomenon and erythromelalgia represent cutaneous microvascular disorders whose pathophysiology appears to relate to disorders of local and/or reflex thermoregulatory control of the skin circulation.

Erythromelalgia

No treatment is consistently effective in the management of patients with erythromelalgia. There is a dearth of adequate studies examining the response of erythromelalgia to therapy. Most recommendations are suggested based on case reports, small case series, and anecdotal reports. The management of erythromelalgia is difficult and frequently involves a multidisciplinary approach. An approach to management of individuals with erythromelalgia includes patient education, learning to avoid episodes relieving discomfort of the episodes, controlling secondary and underlying factors, and use of drugs used to control erythromelalgia.

Impaired neurogenic control of skin perfusion in erythromelalgia

Erythromelalgia is a clinical diagnosis characterized by erythema, increased temperature and burning pain in acral skin. The pain is relieved by cooling and aggravated by warming. The symptoms have been hypothesized to be caused by skin hypoxia due to increased arteriovenous shunting. We examined skin microvascular perfusion in response to vasoconstrictory and vasodilatory stimuli, to characterize local and central neurogenic reflexes as well as vascular smooth muscle and vascular endothelial function, using laser Doppler perfusion measurements in 14 patients with primary erythromelalgia and healthy control persons. Skin perfusion preceding provocative stimuli was significantly reduced in patients with erythromelalgia (p < 0.01). The laser Doppler flowmetry signal after sympathetic stimulation of reflexes mediated through the central nervous system, was significantly diminished in patients with erythromelalgia as compared with healthy controls (Valsalva's maneuver p < 0.01; contralateral cooling test p < 0.05). Local neurogenic vasoconstrictor (venous cuff occlusion and dependency of the extremity) and vasodilator reflexes (local heating of the skin), as well as tests for vascular smooth muscle and vascular endothelial function (postocclusive hyperemic response) were maintained. These results indicate that postganglionic sympathetic dysfunction and denervation hypersensitivity may play a pathogenetic role in primary erythromelalgia, whereas local neurogenic as well as endothelial function is unaffected.

High-dose oral magnesium treatment of chronic, intractable erythromelalgia

BACKGROUND

Previous studies with magnesium have shown beneficial effects in pain syndromes and in vascular disorders (hypertension, migraines, Raynaud's phenomenon). However, results have been variable, possibly because of the limited oral doses achievable due to frequent diarrhea.

OBJECTIVE

To describe the case of a 53-year-old white man (the author) with disabling erythromelalgia (EM) who achieved modest improvement limited by adverse effects with calcium antagonists and then obtained remission with the use of magnesium. Intolerant of several standard magnesium products, he attained high doses of magnesium by taking intravenous-grade magnesium sulfate diluted in water orally (up to 24 mL/d of MgSO4 50% = 1166 mg/d of magnesium).

METHODS

After 12 months of continued improvement, patient 1, a board member of The Erythromelalgia Association, notified other members of the success of this therapy via an Internet communication channel. He encouraged those interested in high-dose magnesium therapy to consult their physicians and to report their results to the Association. Twelve patients responded to this request, describing several standard oral magnesium products.

RESULTS

Overall, 8 of 13 patients (61.5%) reported improvement (1, remission; 3, major improvement; 2, moderate improvement; 2, mild improvement). Four patients (30.8%) reported no response to magnesium therapy, and 1 patient's symptoms worsened. Two patients' magnesium dose was limited because of diarrhea.

CONCLUSIONS

Despite recent progress in understanding and treating EM, this vascular disorder remains painful and life-altering for many patients. In this informal survey, the use of high oral doses of magnesium produced good and sometimes dramatic results in 8 of 13 patients who had been unresponsive to many other treatments. These results suggest a possible role for high-dose oral magnesium in the treatment of EM and, perhaps, other vascular disorders.