Acute lumbosacral polyradiculopathy in acquired immunodeficiency syndrome: experience in 23 patients

We reviewed our experience in 23 patients with acquired immunodeficiency syndrome (AIDS) who had acute lumbosacral polyradiculopathy. The patients developed a distinctive syndrome of rapidly progressive flaccid paraparesis and areflexia that was frequently associated with sphincter disturbances. Persuasive laboratory evidence of a cytomegalovirus polyradiculopathy (polymorphonuclear pleocytosis or confirmatory cerebrospinal fluid culture) was found in 15 of the 23 patients. Treatment with ganciclovir in these patients led to clinical stabilization, although worsening during the first 2 weeks of treatment was common. Most patients with cytomegalovirus polyradiculopathy had severe residual deficits. Metastasis from systemic lymphoma accounted for the polyradiculopathy in 2 other patients. A more benign syndrome was identified in the remaining 6 patients. They generally had slower clinical progression and less severe neurological deficits at their nadir than did patients with cytomegalovirus polyradiculopathy. Unlike patients with cytomegalovirus infection, their cerebrospinal fluid showed a predominantly mononuclear pleocytosis. Moreover, spontaneous improvement without treatment was common. Our experience together with the published experience of others suggests that the acute lumbosacral polyradiculopathy in AIDS is a clinical syndrome with different etiologies and variable clinical outcome. Recognition of this heterogeneity is necessary for the management of individual patients, as well as the interpretation of treatment results.

High-titer selective serum anti-beta-tubulin antibodies in chronic inflammatory demyelinating polyneuropathy

Although chronic inflammatory demyelinating polyneuropathy (CIDP) is presumed to be an autoimmune disorder, no neural antigen has been recognized as an immune target. We found that serum IgM from a patient with CIDP and an IgM paraprotein reacted with a 53-kd protein by Western blot analysis. Amino acid sequence analysis identified this protein as beta-tubulin. We then studied sera from 70 CIDP patients, 35 Guillain-Barré syndrome (GBS) patients, and 483 disease (amyotrophic lateral sclerosis, Alzheimer's disease, multiple sclerosis, diabetes, and other polyneuropathies) and normal controls for selective high-titer anti-beta-tubulin using ELISA methodology. Forty-two percent (30/70) of patients with CIDP had selective high titer IgM reactivity against beta-tubulin; 23% (16/70) had selective high-titer IgG reactivity against beta-tubulin. Overall, 57% of CIDP patients, 20% of GBS patients, and 2% of control patients had selective, high serum IgM or IgG anti-beta-tubulin reactivity. Selective high-titer serum anti-beta-tubulin antibodies occur in a majority of patients with CIDP but are rare in other chronic neuropathies or CNS disorders.

Idiopathic, progressive mononeuropathy in young people

We describe six young patients with insidiously progressive, painless weakness in the distribution of a single major lower extremity nerve. No cause could be found despite extensive evaluation, including surgical exploration. At the time of diagnosis, all patients had weakness and three patients had sensory loss. In all cases, electromyography revealed a chronic axonal mononeuropathy without conduction block or focal conduction slowing. Magnetic resonance, computed tomographic, and ultrasound imaging studies did not identify a region of nerve swelling, mass, or compression. At surgical exploration, the nerve appeared atrophic in two patients, indurated in one patient, and normal in two patients. Biopsy specimens obtained from two abnormal nerves revealed either wallerian degeneration or endoneurial fibrosis. The clinical features of these patients comprise an unusual clinical entity with no known cause or treatment.

Peripheral neuropathies associated with human immunodeficiency virus infection

In the 1990s, HIV has replaced syphilis as the "great masquerader." Virtually every level of the neuraxis may be affected in a patient with HIV infection. The superimposition of multiple levels of neuropathology further complicate the bedside neurologic diagnosis of an AIDS patient. This article has reviewed the variety of forms of peripheral neuropathy that may be associated with HIV infection and its treatment. Distal symmetrical polyneuropathy may be produced in patients with HIV infection by neurotoxic drugs (e.g., vincristine, INH, ddC, or ddI) or by vitamin B12 deficiency or may develop in the later stages of HIV infection without identifiable cause. GBS and CIDP occur with increased frequency in early HIV infection owing to presumed autoimmunity, and these IDPs respond to plasmapheresis or prednisone, similar to HIV-seronegative patients. A limited distribution of mononeuropathy simplex or multiplex occurs in patients with CD4 counts greater than 200; the neuropathy will usually spontaneously improve in these patients. Widespread mononeuropathy multiplex may occur in patients with AIDS and CD4 counts less than 50 and is then usually caused by CMV infections; those neuropathies are usually progressive unless antiviral treatment is given. Progressive polyradiculopathy usually occurs in patients with AIDS and low CD4 counts. If the cerebrospinal fluid has a polymorphonuclear pleocytosis, CMV infection is almost always present, and progression is expected unless ganciclovir therapy is promptly started. Finally, mild autonomic neuropathy is commonly present in HIV-infected patients. Protocols for the evaluation and therapy of cranial and peripheral neuropathies are presented (Figs. 6 and 7). It is unfortunate but likely that increasing numbers of "neuro-AIDS" patients will be encountered, not only in urban medical centers but also in general community practice. The pace at which research in the field of HIV research has proceeded is unprecedented. It is, therefore, important that neurologists stay at the forefront of investigation and clinical care of these complex disorders.

The relative diagnostic sensitivity of different F-wave parameters in various polyneuropathies

We studied F-wave minimum latency, persistence, and chronodispersion in the median and ulnar nerves of 70 controls and 75 patients with various polyneuropathies. Prolonged minimum latency was the most frequent F-wave abnormality in all groups of patients with polyneuropathy. The finding of decreased persistence or absence of F-responses was comparable in sensitivity to prolonged minimum latency in Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP), whereas chronodispersion had a comparable sensitivity only in CIDP. Decreased persistence of obtained F-responses, and the absence of F-responses in nerves with low compound muscle action potential amplitudes, were nonspecific findings. F-wave studies often provide useful additional information in the evaluation of patients suspected of having a polyneuropathy. In patients with axonal polyneuropathies, we found that F-wave studies are significantly more sensitive than standard motor conduction studies in identifying physiological abnormalities of motor axons. Furthermore, in a patient with an acquired polyneuropathy, the finding of markedly prolonged minimum latency, or the absence of F-responses in nerves with normal CMAP amplitude, is highly specific for the presence of demyelination.

AAEM minimonograph #38: neuropathies in connective tissue disease

Neuropathies are common in patients with known or suspected connective tissue disease. A vasculitic mononeuropathy multiplex is often seen in patients initially presenting with polyarteritis nodosa or developing arteritis as a complication of rheumatoid arthritis. However, vasculitic neuropathy may become confluent and present as as distal symmetrical polyneuropathy or occur without systemic necrotizing vasculitis. Distal symmetrical polyneuropathies without associated vasculitis are also common in many connective tissue diseases. Compression neuropathies, especially carpal tunnel syndrome, occur with increased frequency in rheumatoid arthritis. Finally, certain neuropathies may be the major presenting feature of particular connective tissue diseases. For example, trigeminal neuropathy often heralds the onset of systemic sclerosis or mixed connective tissue disease, and sensory neuronopathy may be the initial presenting feature of Sjögren's syndrome.

Botulinum toxin therapy for limb dystonias

We investigated the effectiveness of botulinum toxin in 17 patients with limb dystonias (10 with occupational cramps, three with idiopathic dystonia unrelated to activity, and two each with post-stroke and parkinsonian dystonia) in a placebo-controlled, blinded study. We identified affected muscles clinically and by recording the EMG from implanted wire electrodes at rest and during performance of tasks that precipitated abnormal postures. There were three injections given with graded doses of toxin (average doses, 5 to 10, 10 to 20, and 20 to 40 units per muscle) and one with placebo, in random order. Subjective improvement occurred after 53% of injections of botulinum toxin, and this was substantial in 24%. Only one patient (7%) improved after placebo injection. Subjective improvement occurred in 82% of patients with at least one dose of toxin, lasting for 1 to 4 months. Response rates were similar between clinical groups. Objective evaluation failed to demonstrate significant improvement following treatment with toxin compared with placebo. The major side effect was transient focal weakness after 53% of injections of toxin.

Quantitative motor unit analysis: the effect of sample size

This study of quantitative electromyography examines the influence of sample size on motor unit action potential (MUAP) tolerance limits, intertrial variability, and diagnostic sensitivity. We recorded 20 randomly selected MUAPs from the biceps muscle twice in 21 normal subjects, and once in 10 patients with myopathy. The 95% tolerance limits for mean total duration in normal subjects progressively narrowed from 6.6 to 14.2 ms for 5 MUAPs to 7.4 to 13.0 ms for 20 MUAPs. The 95% tolerance limits for intertrial variability were +/-22% for mean total duration of 20 MUAPs. Larger sample size had a greater effect on reducing intertrial variability than on narrowing 95% tolerance limits for amplitude and area. Quantitative EMG results for duration supported the presence of myopathy in 2 of 10 patients with analysis of 5 MUAPs, and 9 patients with analysis of 20 MUAPs. Although analysis of 5 potentials may be adequate for diagnosis occasionally, quantitative analysis of 20 MUAPs narrows tolerance limits, reduces intertrial variability, and improves diagnostic sensitivity.

AAEM case report #23: acute paralytic poliomyelitis

A 56-year-old man with acute paralytic poliomyelitis is described. The illness started with fever and diarrhea after an overseas trip, and an enterovirus other than poliovirus was isolated from the patient's stool. The onset of weakness was rapid and asymmetric, with primary involvement of the lower extremities. Nerve conduction studies revealed low amplitude motor responses after the first week, with normal results for sensory studies. Serial electromyographic studies were performed, documenting acute denervation followed later by reinnervation in the distribution of multiple segments. The clinical and electrodiagnostic features of acute poliomyelitis are reviewed.

Clinical and electrodiagnostic features of X-linked recessive bulbospinal neuronopathy

We describe four men from two kinships affected with X-linked recessive bulbospinal neuronopathy, and one sporadic case. All developed postural tremor, weakness, and fasciculations, with onset from age 25 to 39 years. Weakness began in the pelvic girdle or hands, with dysphagia or dysarthria occurring years later in two. Sensory symptoms were present in only one, who also had diabetes mellitus. In contrast, sural nerve action potentials were small or absent in all. Needle EMG showed widespread chronic partial denervation with reinnervation. The characteristic twitching of the chin produced by pursing of the lips consisted of repetitive or grouped motor unit discharges, rather than fasciculations. Broader awareness of the distinctive features of bulbospinal neuronopathy will probably increase the frequency of its recognition. Diagnosis is important for purposes of providing a prognosis for affected men and genetic counseling for affected families.

Change in pattern of muscle activity following botulinum toxin injections for torticollis

Twenty patients with torticollis had electromyographic studies of their neck muscles performed before and after a series of local injections of botulinum toxin. The pattern of muscle activity changed after the injections, and this effect persisted even after head position had returned to baseline. Patients who did not experience any clinical benefit from the injections also demonstrated a change in the pattern of muscle activity. These results suggest that the underlying abnormality in torticollis usually involves a general motor program for head position, rather than the activity of individual neck muscles.

A comparison of thermography and electromyography in the diagnosis of cervical radiculopathy

We studied 20 asymptomatic control subjects and 14 patients with clinically unequivocal cervical radiculopathy to compare the diagnostic value of thermography with that of electromyography. We measured the average skin temperature of designated regions over the neck, shoulder, and upper extremities. We then compared the temperature between corresponding regions of the two limbs, and between fingers innervated by different roots in the same hand. Thermography was abnormal in 6 patients (43%), whereas electromyography was abnormal in 10 (71%). Thermographic abnormalities were seen only in the hands and fingers, and the pattern did not follow the dermatome of the clinically involved cervical root. When compared to electromyography, thermography provided no additional diagnostic information. Thus, thermography does not have an established role in the evaluation of patients with cervical radiculopathy.

A comparison of magnetic and electrical stimulation of peripheral nerves

We compared magnetic stimulation using different coil designs (2 rounded coils and a butterfly-prototype coil) with electrical stimulation of the median and ulnar nerves in 5 normal subjects. Using magnetic stimulation we were able to record technically satisfactory maximal sensory and motor responses only with the butterfly coil. Submaximal electrical stimuli preferentially activated sensory rather than motor axons, but submaximal magnetic stimuli did not. The onset latency, amplitude, area and duration of responses elicited electrically or magnetically with the butterfly coil during routine sensory and motor nerve conduction studies were similar, and motor and sensory conduction velocities were comparable when studied over long segments of nerve. However, the motor conduction velocities with magnetic and electrical stimulation differed by as much as 18 m/sec in the across-elbow segment of ulnar nerve. Thus, recent developments in magnetic stimulator design have improved the focality of the stimulus, but the present butterfly coil design cannot replace electrical stimulation for the detection of focal changes in nerve conduction velocity at common entrapment sites, such as in the across-elbow segment of the ulnar nerve.

Somatic mosaicism at the Duchenne locus

Results of testing a family for carrier status and prenatal diagnosis for Duchenne muscular dystrophy (DMD) are best explained by somatic mosaicism in the maternal grandfather. This genetic situation was identified using segregation analysis of intragenic DNA polymorphisms, a serum creatine phosphokinase assay, and physical examination of the patients. This event at the DMD locus represents one more potential source of error in carrier testing and prenatal diagnosis.

Electrodiagnostic features of the Guillain-Barré syndrome: the relative sensitivity of different techniques

We compared the diagnostic sensitivity of somatosensory evoked potentials (SEPs) and F waves with peripheral motor and sensory nerve conduction studies in 15 patients with the Guillain-Barré syndrome. All 4 types of studies were performed on 44 nerves (17 median, 12 ulnar, and 15 lower extremity). In the lower extremities, we used the peroneal nerves for all types of study except peripheral sensory conduction studies, which were performed on the sural nerve. We detected abnormalities by peripheral motor conduction studies in 33 of 44 nerves, by F waves in 31, by SEPs in 23, and by peripheral sensory conduction in 17. The cumulative sensitivity increased with the testing of multiple nerves by motor nerve conduction, sensory nerve conduction, and F-wave studies, but not with multiple SEPs. F-wave studies were significantly more sensitive than SEPs in identifying abnormalities. Thus, the recording of SEPs is indicated for diagnosis of the Guillain-Barré syndrome only if peripheral nerve conduction and F-wave studies are normal.

Lower motor neuron syndromes defined by patterns of weakness, nerve conduction abnormalities, and high titers of antiglycolipid antibodies

We studied 74 patients with progressive, asymmetrical lower motor neuron syndromes. Clinical features of these patients, including age, sex, disease duration, patterns of weakness, and reflex changes, were evaluated by review of records. In each patient the clinical features were compared to the type of nerve conduction abnormalities and to the specificities of high-titer serum antiglycolipid antibodies. Antibody specificities were determined by an enzyme-linked immunosorbent assay using purified glycolipids and carbohydrates as substrates. Our results show that high titers of antibodies to glycolipids are common in sera of patients with lower motor neuron syndromes. Selective patterns of reactivity indicate that specific carbohydrate epitopes on the glycolipids are the targets of the high-titer antibodies in individual patients with lower motor neuron syndromes. Several distinct lower motor neuron syndromes can be identified based on clinical, physiological, and antiglycolipid antibody characteristics. These syndromes include multifocal motor neuropathy with evidence of multifocal conduction block on motor, but not sensory, axons and frequent (84%) high titers of anti-GM1 ganglioside antibodies; a lower motor neuron syndrome with predominantly distal weakness early in the disease course, no conduction block, and a high incidence (64%) of anti-GM1 antibodies; and a lower motor neuron syndrome with predominant early weakness in proximal muscles and serum antibodies to asialo-GM1 that do not cross-react with GM1 ganglioside.

The role of thermography in the evaluation of lumbosacral radiculopathy

We studied 27 normal subjects and 30 patients with low back pain to evaluate the diagnostic accuracy of thermography in the diagnosis of lumbosacral radiculopathy. Thermographic abnormality was defined as the presence of either interside temperature difference exceeding 3 standard deviations from the normal mean, or an abnormal heat pattern overlying the lumbosacral spine. In patients with clinically unequivocal radiculopathy, thermography and electrophysiologic study were similar in diagnostic sensitivity, and the 2 methods agreed on the presence or absence of abnormality in 71% of cases. However, the thermographic findings had limited localizing value. Relative limb warming was often seen in patients with acute denervation on EMG, and limb cooling in those with more chronic lesions, but the side of the root lesion could not be identified confidently by thermography alone. Moreover, thermographic abnormalities appeared not to follow a dermatomal distribution and failed to identify the clinical or electrophysiologic level of radiculopathy in most cases. Thus, the thermographic findings are nonspecific, of little diagnostic value, and of uncertain prognostic relevance.

Evaluation of thermography in the diagnosis of selected entrapment neuropathies

We studied 20 normal subjects, 22 patients with carpal tunnel syndrome, and 15 with ulnar neuropathy at the elbow to compare the diagnostic accuracy of infrared thermography with that of conventional electrodiagnostic studies. We found abnormal thermograms in 55% of patients with carpal tunnel syndrome and 47% with ulnar neuropathy, using 2.5 SD from the normal mean as criteria for abnormality. The abnormalities consisted of either an increase in interside temperature difference in the fingers and hands or an alteration of the normal thenar-hypothenar temperature gradient in the fingers. The sensitivity of thermography was considerably lower than that of conventional electrodiagnostic methods. Moreover, the thermographic abnormalities were nonspecific, and could be misleading as they did not reliably identify the side of lesion or distinguish between median or ulnar nerve involvement. Thus, thermography is not helpful in the diagnosis of these two common entrapment neuropathies.

Neuromuscular effects distant from the site of botulinum neurotoxin injection

We assessed the severity and temporal profile of distant neuromuscular effects from a single dose (280 units) of botulinum neurotoxin injected into neck muscles for torticollis. We performed single-fiber EMG studies on the biceps brachii of six patients to measure jitter (20 pairs) and fiber density on the initial treatment day and then again, at least once more, after 2 to 12 weeks. No patient developed weakness beyond the neck muscles or decrement of the biceps response to repetitive 3-Hz nerve stimulation. Between the baseline and the last follow-up study, the average of mean MCD increased from 29 microseconds to 38 microseconds (31%). Mean fiber density increased concurrently or earlier from 1.35 to 1.79 (33%). There were no electrophysiologic signs of presynaptic blockade, even at 2 and 4 weeks. The effects we observed are compatible with stimulation of terminal sprouting by the neurotoxin, without significant presynaptic inhibition of acetylcholine release. We therefore believe that higher dosages of the neurotoxin may be used if clinically indicated.

Peripheral neuropathy associated with acquired immunodeficiency syndrome. Prevalence and clinical features from a population-based survey

We prospectively studied 40 hospitalized patients who had well-established diagnoses of acquired immunodeficiency syndrome. Patients with confounding risk factors for neuropathy were excluded; none of the study patients had known vitamin deficiency, alcoholism, or any metabolic, drug, or toxic factor. Clinical and electrophysiologic evidence of a distal symmetric polyneuropathy was found in 35% (13/37) of the patients. Symptoms and signs of neuropathy were usually mild, and painful dysesthesias were uncommon. Amplitude reduction of sural nerve action potentials distinguished all patients with from those without clinical neuropathy. Results of other electrophysiologic studies of sural, peroneal, and median nerves were typically normal. These results provide evidence of distal axonal degeneration. Neuropathy occurred only in patients with systemic illness longer than five months' duration. When compared with patients without neuropathy, these patients had more severe weight loss and a higher incidence of clinical dementia. Follow-up evaluation showed no evidence of clinical progression over a six-month period. The pathogenesis of this common distal axonal polyneuropathy is unknown and warrants further investigation.

AAEE case report #15: ulnar neuropathy at or distal to the wrist

A 56-year-old woman developed insidiously progressive, painless weakness of her left hand. Clinical and electrodiagnostic abnormalities were limited to the motor function of the hand, with the hypothenar less affected than more distal ulnar muscles. Compression of the distal ulnar nerve by a ganglionic cyst was surgically relieved and there was postoperative improvement. The electrodiagnosis of ulnar neuropathy at or distal to the wrist is reviewed together with relevant anatomic and clinical aspects of these uncommon lesions.