Plasma exchange versus intravenous immunoglobulin treatment in myasthenic crisis.

We performed a retrospective multicenter chart review to compare the efficacy and tolerance of plasma exchange (PE) and intravenous immunoglobulin (i.v.Ig) in treatment of 54 episodes of myasthenic crisis. After adjustment for other variables, PE (compared with i.v.Ig) was associated with a superior ventilatory status at 2 weeks (partial F = 6.2, p = 0.02) and 1 month functional outcome (partial F = 4.5, p = 0.04). However, the complication rate was higher with PE compared with i.v.Ig (13 versus 5 episodes, p = 0.07).

Autoimmune diabetic neuropathy.

Recent work has shown that inflammatory vasculopathy is commonly seen in biopsies of diabetic patients with neuropathy. Most of these patients have had syndromes consistent with proximal diabetic neuropathy or amyotrophy. This suggests that inflammatory vasculopathy is important in the pathogenesis of these disorders. Immunosuppressive therapy may benefit many of these patients.

Diabetic muscle infarction.

PURPOSE: To describe the clinical, histologic, and radiologic findings in patients with diabetic muscular infarction (DMI). MATERIALS AND METHODS: Descriptive case series of 3 patients with DMI and 22 previously reported cases (MEDLINE data base search) in the English literature are presented. RESULTS: Diabetic muscular infarction is usually seen in patients with long-standing insulin-dependent diabetes and multiple end-organ microvascular complications. Two-thirds of patients with DMI are women, with a mean age at presentation of 39 +/- 12 years. The typical clinical presentation includes abrupt onset of thigh pain and tenderness. There is a palpable, painful mass, with swelling and induration of the surrounding tissue without systemic symptoms or signs. The painful lesion persists for weeks, occasionally with exacerbations of symptoms, then spontaneously resolves over several weeks to months. Recurrent episodes are reported in half of the patients. Muscles commonly affected are the vastus lateralis, thigh adductors, and biceps femoris; but calf muscles may be involved as well. Active pathologic changes in the muscle are more sensitively evaluated with T2-weighted sequences on magnetic resonance (MR) imaging, which shows high intensity in involved muscle. Histologic features of DMI consist of large areas of muscle necrosis and edema. Regenerating muscle fibers and lymphocytic interstitial infiltration may be present. CONCLUSION: Diabetic muscular infarction is a rare complication of diabetes mellitus. In most patients, the diagnosis can be made when the characteristic clinical presentation is combined with a typical MR imaging results. Muscle biopsy can be helpful in establishing the diagnosis of DMI, but histologic findings are not specific. Awareness of this syndrome plus MR imaging as the first diagnostic test should lead to the correct diagnosis and shorter hospitalization.

Successful treatment of neuropathies in patients with diabetes mellitus.

OBJECTIVES: To report and characterize two forms of disabling progressive peripheral neuropathy in patients with diabetes mellitus, which respond to anti-inflammatory and/or anti-immune treatment. DESIGN: Review of clinical, electrophysiologic, and pathologic findings and results of treatment. SETTING: University medical center. PATIENTS: Twenty-one patients with diabetes mellitus to whom we gave anti-inflammatory and/or anti-immune treatment for progressive peripheral neuropathy during the past 6 years. MAIN OUTCOME MEASURES: Patients were interviewed and examined at intervals before and after beginning treatment with intravenous immunoglobulin (n = 15), prednisone (n = 13), cyclophosphamide (n = 5), plasma exchange (n = 3), and azathioprine (n = 1) (alone or in combination). RESULTS: Fifteen patients had evidence of axonal neuropathy by electrophysiologic studies (group A). All 15 patients had non-insulin-dependent diabetes mellitus, 10 patients had weight loss, and 13 patients had prominent involvement of thighs and/or thoracic bands consistent with diabetic amyotrophy or mononeuropathy multiplex. Small vessel disease was seen in all 10 patients who underwent biopsy, with perivascular or vascular inflammation seen in seven patients. Six patients had demyelinating neuropathy by electrophysiologic criteria (group B). All these patients had insulin-dependent diabetes mellitus, and no one had weight loss. The process was asymmetric in three patients and involved thoracic or abdominal regions in two patients. Onion bulbs were seen in all four patients who underwent biopsy, but no vascular inflammation or occlusion was seen. In all patients in both groups, worsening of their conditions stopped and improvement started after beginning treatment. CONCLUSION: Neuropathies responsive to anti-inflammatory and/or anti-immune therapy in patients with diabetes mellitus include (1) multifocal axonal neuropathy caused by inflammatory vasculopathy, predominantly in patients with non-insulin-dependent diabetes mellitus, indistinguishable from diabetic proximal neuropathy or mononeuropathy multiplex, and (2) demyelinating neuropathy indistinguishable from chronic inflammatory demyelinating polyneuropathy, predominantly in patients with insulin-dependent diabetes mellitus.

Lymphomatous polyneuropathy. Biopsy of clinically involved nerve and successful treatment.

We present a patient with large-cell lymphoma in remission who, over several weeks, developed widespread multifocal polyneuropathy. There was involvement of all four limbs, most severely the left upper extremity that had become useless. Biopsy of the left saphenous nerve within an area of sensory loss showed lymphoma in the endoneurium. There was no other evidence of recurrent lymphoma despite extensive investigation, including bone marrow, lumbar puncture, magnetic resonance imaging of the spine, and computed tomography of the abdomen and pelvis. Intensive systemic chemotherapy was accompanied by nearly complete recovery. Biopsy of a symptomatic nerve is preferable to routine sural nerve biopsy in this condition because of its patchy distribution. Treatment with systematic chemotherapy can be effective.

Myasthenia gravis presenting as weakness after magnesium administration.

We studied a patient with no prior history of neuromuscular disease who became virtually quadriplegic after parenteral magnesium administration for preeclampsia. The serum magnesium concentration was 3.0 mEq/L, which is usually well tolerated. The magnesium was stopped and she recovered over a few days. While she was weak, 2-Hz repetitive stimulation revealed a decrement without significant facilitation at rapid rates or after exercise, suggesting postsynaptic neuromuscular blockade. After her strength returned, repetitive stimulation was normal, but single fiber EMG revealed increased jitter and blocking. Her acetylcholine receptor antibody level was markedly elevated. Although paralysis after magnesium administration has been described in patients with known myasthenia gravis, it has not previously been reported to be the initial or only manifestation of the disease. Patients who are unusually sensitive to the neuromuscular effects of magnesium should be suspected of having an underlying disorder of neuromuscular transmission.

Biopsy-proven cerebral vasculitis associated with cocaine abuse.

We report cerebral vasculitis in 2 cocaine users who developed symptoms (transient blindness and persistent headache) while smoking "crack," followed by progressive widespread cerebral dysfunction with focal signs over the next few weeks. One patient had smoked crack exclusively, and the other also used cocaine intravenously. Sedimentation rates were elevated and HIV titers negative. Arteriography was normal in 1 patient and in the other showed multiple large-vessel occlusions without beading. Brain biopsy showed vasculitis involving small vessels in both patients. Multinucleated cells were present in the neuropil, but there were no granulomas or evidence of infection. One patient improved significantly with corticosteroid treatment, and made a good recovery. The other died despite corticosteroid and cyclophosphamide treatment.

Sural nerve biopsy in chronic inflammatory demyelinating polyradiculoneuropathy.

We compared histologic features of sural nerve biopsies in 14 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with those in other forms of neuropathy. In CIDP endoneurial pericapillary cellular infiltrates were found in 4 patients (29%), onion bulbs in 5 patients (36%), and predominant demyelination in 7 patients (50%). None of these abnormalities was specific, but cellular infiltrates and onion bulbs appear to be diagnostically useful when combined with clinical information. To detect macrophage infiltration of myelin, cell nuclei were counter-stained in 20 teased fiber preparations. Nine patients with CIDP had a significantly higher mean number of cells per centimeter of teased fiber than 11 patients with other neuropathies. Despite overlap, significant infiltration of myelin detected by this method suggests CIDP in an appropriate clinical setting.

Distal vacuolar myopathy with complete heart block.

We describe a 26-year-old man with a predominantly distal myopathy and complete heart block. A muscle biopsy specimen demonstrated numerous vacuoles, which, by electron microscopy, contained membranous whorls. Filamentous inclusions characteristic of inclusion body myositis were not seen. It is important to be aware that life-threatening cardiac disease may occur in this setting.

Infiltrative polyneuropathy due to acute monoblastic leukemia in hematologic remission.

A 66-year-old man with acute monoblastic leukemia developed acute polyneuropathy with quadriplegia, autonomic instability, and respiratory failure while he was in hematologic remission following both systemic and intrathecal chemotherapy. Autopsy revealed dense infiltration of somatic and autonomic peripheral nerves, sparing the meninges. There was a small peripheral infiltrate in one of four dorsal root ganglia, but, otherwise, sensory and autonomic ganglia were normal. The blood-nerve barrier may allow some malignant cells to escape cytotoxic agents. The epineurium and ganglia lack a blood-tissue barrier, and malignant cells could have been eradicated at those sites.

Adverse effect of verapamil in a patient with the Lambert-Eaton syndrome.

A patient with the Lambert-Eaton syndrome (LES) and small cell lung cancer developed respiratory failure several hours after verapamil was given. Improvement in respiratory function did not occur when guanidine was given, but was delayed until verapamil was discontinued 3 days later. Although other factors may have contributed to the clinical deterioration of our patient, the temporal relationship to verapamil and the theoretical danger of calcium channel blockade lead us to believe that the drug should be used cautiously in LES.