Cutaneous silent period changes in Type 2 diabetes mellitus patients with small fiber neuropathy

OBJECTIVE

Small myelinated (A-delta) and unmyelinated (C) somatic sensory fibers are initially affected and may be the earliest exhibited sign of neuropathy in glucose dysmetabolism. Cutaneous silent period (CSP) is an inhibitory spinal reflex and its afferents consist of A-delta nerve fibers. The aim of this study was to evaluate CSP changes in Type 2 diabetic patients with small fiber neuropathy.

METHODS

Forty-three patients and 41 healthy volunteers were included. CSP latency and duration, as well as CSP latency difference of the upper and lower extremities, were examined.

RESULTS

Nerve conduction studies were within normal limits in both groups. Lower extremity CSP latency was longer (122.1+/-15.5 vs. 96.4+/-6.4 ms; p<0.001), CSP duration was shorter (29.5+/-8.9 vs. 43.1+/-5.0 ms; p<0.001), and latency difference was longer (48.1+/-12.6 vs. 22.7+/-3.7; p<0.001) in patients than controls. The difference was more significant in patients with neuropathic pain. No significant difference existed in upper extremity on CSP evaluation.

CONCLUSION

The CSP evaluation together with nerve conduction study, has been demonstrated to be beneficial and performance of latency difference in addition to CSP latency and duration may be a valuable parameter in electrophysiological assessment of diabetic patients with small fiber neuropathy.

SIGNIFICANCE

An additional CSP evaluation may be considered in cases which nerve conduction studies do not provide sufficient information.

Sunrise-Related Headache: Case Report

A male, 34 years of age, suffers from headaches, red and watery eyes. The headaches began in childhood; the frequency of headaches has increased over the years and in the last decade headaches have occurred on a daily basis. If he wakes up before sunrise he feels much better and free of a headache; however, once he continues to sleep during and after sunrise, he suffers from tiredness, headache and nervousness. On magnetic resonance imaging (MRI), benign neuroepithelial cysts or a chronic infarct area was reported at the junction of the left medio-lateral zone of hypothalamus. After repeated MRI examinations, it was decided that the lesion on the left medio-lateral zone of hypothalamus may have disrupted the pineal gland and changed melatonin secretion. It was decided to treat him with 3 mg melatonin daily before going to bed. After a week of treatment, the patient reported that he felt very fresh and was virtually free of headaches.

Early diagnosis and treatment reverse clinical features in Hoffmann's syndrome due to hypothyroid myophaty: a case report

Hypothyroidism is a frequently diagnosed endocrine disorder that has characteristic clinical signs and symptoms. Myopathy is one of the manifestations of hypothyroidism and relatively common. We report a case of Hoffmann's Syndrome due to hypothyroid myopathy documented by clinical features, laboratory findings and positive response to thyroid hormone replacement therapy. A man, age of 22, was diagnosed as having primary hypothyroidism at the age of five, had been describing progressive weakness in his arms and legs for two months and complained about generalized muscle cramps and pain. He was diagnosed with Hoffmann's syndrome with low levels of thyroid hormones and high levels of muscle enzymes. After six months of thyroid hormone replacement therapy, both the clinical picture and laboratory findings were remarkably improved.

Comparison of sensitivities of macro EMG and concentric needle EMG in L4 radiculopathy

The purpose of this study was to compare the sensitivities of macro EMG (mEMG) and concentric needle EMG (cnEMG) in showing abnormality in L4 radiculopathy. We evaluated 23 patients with clinically and radiologically proven L4 root lesions. Among these patients, 21 (92%) had cnEMG abnormalities. Out of 21 patients with cnEMG abnormality, 3 (14%) had fibrillations and positive sharp waves, 8 (38%) had interference pattern abnormality and all of them had motor unit potential (MUP) abnormality on quantitative MUP analysis. Seventeen patients (74%) had mEMG abnormality. Diagnostic yield of cnEMG is higher than mEMG in L4 radiculopathy. mEMG may not contribute much to the diagnosis of lumbar radiculopathy.

Postexercise facilitation of reflexes is not common in Lambert-Eaton myasthenic syndrome

Postexercise facilitation (PEF) with clinical reflexes, H-reflex, and T-reflexes at the ankle and knee was systematically studied in 16 patients with Lambert-Eaton myasthenic syndrome (LEMS). PEF was observed in ankle and knee deep tendon reflexes in five patients, in H-reflex in three patients, and in T-reflexes in six patients. When all reflex tests were combined, 7 (43.7%) of 16 patients showed PEF by at least one test. The authors conclude that the PEF of reflexes, the most helpful diagnostic clinical marker for LEMS, is not common.

Neurolymphomatosis associated with muscle and cerebral involvement caused by natural killer cell lymphoma: a case report and review of literature

We report a biopsy-proven case of neurolymphomatosis (NL) presenting with sensory motor axonal polyneuropathy, polymyositis, and cerebral involvement. Ours is the second reported case of NL caused by natural killer-cell lymphoma defined by morphology and immunophenotyping. For 3 months, the patient developed stocking-glove distribution of hypesthesia, subacute progressive weakness and mental deterioration. EMG showed severe sensorimotor mixed axonal-demyelinating polyradiculoneuropathy. Lumbar puncture revealed mildly high protein level with normal glucose and cell count. Sural nerve biopsy demonstrated lymphomatous axonal neuropathy and muscle biopsy was indicative of lymphomatous polymyositis. Brain MRI revealed multiple white matter lesions, consistent either with progressive multifocal leukoencephalopathy or cerebral lymphoma. Bone marrow biopsy showed neoplastic infiltrates. The patient died of multiple organ failure prior to initiation of chemotherapy.

Essential startle disease may not be a uniform entity

A 25-year-old man with essential startle disease has been reported. He had a history of sudden jerks and falls in response to unexpected stimuli. Abnormal falling developed when he learned to walk. No similar cases are known in his family. Physical examination revealed hyperreflexia. Pathologic startle reflex was elicited by light touching on the patient's nose, clapping or making other noises. EEG response to startle stimuli consisted of spikes recorded from both centroparietooccipital regions immediately preceding diffuse muscle and movement artifacts. The motor responses to auditory stimuli, which are startle reflex on the orbicularis oculi, sternocleidomastoid, biceps and quadriceps femoris muscles, habituated within 2-4 trials. Electrical stimulation of the median nerve at the wrist elicited a consistent C reflex (cortical long loop reflex) but not any giant cortical somatosensory evoked potentials. Our patient showed early disease onset and habituation of motor response, which are not seen in other essential hyperekplexia cases, and clinically differs from the patients with hereditary hyperekplexia in which neonatal rigidity, epilepsy, apneic attacks, low intelligence, congenital dislocated hips and inguinal hernia can be seen in differing frequency.

Median nerve somatosensory evoked potentials recorded with cephalic and noncephalic references in central and peripheral nervous system lesions

Somatosensory evoked potentials (SSEP) to electrical stimulation of the median nerve by using cephalic and noncephalic references were studied to detect the generator sources of short latency evoked potentials in 29 patients with cerebral, brainstem, spinal and peripheral nerve lesions. Patients were divided into six groups according to the localization of their lesions: group 1: cortical and subcortical lesions, group 2: basal ganglion lesions, group 3: pons and mesencephalon lesions, group 4: diffuse cerebral lesions, group 5: cervical cord lesions, group 6: brachial plexus lesions. Potentials were recorded using cephalic and noncephalic references after median nerve stimulation. Evidence obtained from patients suggested the following origins for these short latency SSEPs: P9 may arise in brachial plexus, P11 in dorsal basal ganglions or dorsal column, P13 and P14 in the nucleus cuneatus and lemniscal pathways, N16 in subthalamic structures and most likely mid and lower pons, N18 from the thalamus and thalamocortical tract, and N20 from primary somatosensory cortex.

Turns-amplitude analysis and motor unit potential analysis in myasthenia gravis

OBJECTIVES

The aims of this study were to investigate myopathic changes in myasthenia gravis (MG) by using turns-amplitude analysis (TAA) and quantitative motor unit potential duration analysis (MUPan), to correlate myopathic changes with severity and duration of the disease and the results of diagnostic tests including repetitive nerve stimulation test (RNS), single fiber electromyography (SFEMG), and anti-acetylcholine receptor antibody (AChR-ab), and to compare the sensitivities of these two methods in detecting myopathic changes in MG.

MATERIALS AND METHODS

We studied both MUPan and TAA in 32 patients with MG.

RESULTS

The MUPan study showed myopathic changes in 12 patients (37.5%); TAA revealed a myopathic pattern in 4 (12.5%) and a neurogenic pattern in 4 cases (12.5%). Two of the 4 patients with a myopathic change by TAA also had short-duration mean MUP on the MUPan. No statistically significant association was found between the myopathic changes either by MUPan or TAA, and the various clinical and laboratory features.

CONCLUSION

We conclude that MUPan is a more sensitive method than TAA in showing myopathic changes in MG, and that TAA is of limited help in demonstrating them.

Ice-pack test in myasthenia gravis: electrophysiological basis

We report the first study in which the repetitive nerve stimulation (RNS) test was performed in conjunction with the ice-pack test in three patients with myasthenia gravis. All three patients showed an unequivocal improvement in ptosis on the side where an ice pack was placed. RNS test in the facial nerve revealed a definite improvement in the decremental response. From this we conclude that the ice-pack test produces a clinical and electrophysiological improvement in myasthenia gravis.

Median nerve somatosensory evoked potentials: recording with cephalic and noncephalic references

We performed both cephalic and noncephalic reference SEP recordings with median nerve stimulation in normals and compared the results obtained from both recordings. Median nerve SEP with non cephalic reference revealed four positive and three negative potentials on scalp, while median nerve SEP with cephalic reference showed only one negative potential on scalp. We conclude that potentials originated from subcortical regions can be recorded from scalp by using noncephalic reference, which is not possible by cephalic reference and potential N20 obtained from somatosensory cortex by using cephalic reference does not present a single potential, consisting of combination of a few potentials. To differentiate these potentials, noncephalic reference must be used.

Migrainous stroke causing bilateral anterior cerebral artery territory infarction

A 38-year-old man developed bilateral anterior cerebral artery territory infarction during the course of a migraine. Magnetic resonance imaging showed bilateral ischemic lesions involving the cortex of the paramedian region of the frontal and parietal lobes, more prominent on the right. Cerebral angiography was normal. To our knowledge, this is the first report of bilateral anterior cerebral artery territory infarction from migraine.

Event-related brain potentials in male hypogonadism

Several studies based on psychometric tests have determined an impairment of cognitive functions in patients with androgen deficiency. However, little is known about event-related potentials (ERPs) alterations in male hypogonadism. We investigated alterations of ERP in male hypogonadism before and 3 months after gonadotropin treatment. ERPs were elicited in 20 untreated male patients with idiopathic hypogonadotropic hypogonadism (IHH) (mean age: 21.1+/-1.4 years) and in a group of 30 male controls with comparable mean age and educational level. ERP recordings were repeated 3 months after hCG/hMG treatment. Untreated hypogonadal patients had longer mean P300 latencies and increased P300 amplitudes when compared to those in controls (321.6+/-18.5 vs 299.3+/-20.1 msec, p=0.0002; 12.15+/-4.47 vs 9.38+/-3.02 microV, p=0.011, respectively). The mean P300 latencies did not change significantly 3 months after gonadotropin treatment, while P300 amplitudes were decreased significantly. P300 latencies did not correlate with serum testosterone and other hormone levels. We conclude that prolongation of P300 latencies and increased P300 amplitudes are associated with male hypogonadism, but P300 prolongation is not reversed 3 months after gonadotropin treatment. These findings confirm the occurrence of cognitive defects in hypogonadal patients and would support the hypothesis that perinatal androgen deficiency contributes to an insufficient cognitive development.

Unusual late responses in a patient with an Arnold-Chiari malformation

We studied a young man with spastic right hemiparesis, in whom supramaximal stimulation of the left posterior tibial nerve produced toe movements of the both feet and associated late responses in the flexor hallucis brevis muscle bilaterally. These findings indicate that, in this patient, there are central connections between peripheral afferents and contralateral alpha-motor neurons. It may be that such connections are normally present but that they are too weak in normal subjects to produce firing of the alpha-motor neurons by themselves. If so, the loss of cortical inhibition in our patient may have allowed these connections to produce movement.

New near-nerve needle nerve conduction technique: differentiating epicondylar from cubital tunnel ulnar neuropathy

At the elbow, the ulnar nerve is compressed most commonly either in the epicondylar groove or at the cubital tunnel. While conventional electrodiagnosis may localize an ulnar neuropathy to the elbow, separating epicondylar syndrome (tardy ulnar nerve palsy) from cubital tunnel syndrome is more difficult. We describe a new method using a near-nerve needle technique for distinguishing these two types of ulnar neuropathy at the elbow. We placed three active needle electrodes across the elbow: the first was 4 cm above, and the second and third were 1.5 cm and 6 cm below the medial epicondyle, respectively. The latter two points were chosen because of the presence of the cubital tunnel in this segment. Sensory, motor, and mixed nerve conduction studies (NCS) were performed on these two segments (elbow segment and cubital tunnel segment) in 26 normal nerves and normal data were established. We also present 7 cases of epicondylar ulnar nerve palsy and 1 case of cubital tunnel syndrome in which we were able to confirm the diagnosis with the present method. In 3 cases of epicondylar ulnar nerve palsy, the present method accurately localized the lesion when other methods failed. We believe that this method will be helpful in distinguishing cubital tunnel syndrome from epicondylar ulnar nerve palsy, especially in early ulnar neuropathy in which only sensory fibers are involved.

Beneficial effect of thyrotropin-releasing hormone on neuropathy in diabetic rats

Thyrotropin releasing hormone (TRH) is therapeutically effective in experimental and clinical spinal injury. The effects of TRH on diabetic neuropathy are not known. The aim of the present study was to investigate the electrophysiological effects of TRH in the streptozotocin diabetic rats. Three groups of rats were studied, non-diabetic control (n = 10), diabetic controls (n = 8), and TRH treated diabetic rats (n = 9). Administration of TRH or saline and electrophysiological measurements were performed 4 weeks after induction of diabetes. TRH was given intraperitoneally in a dose of 600 microg (3 ml). Nerve conduction velocity (NCV), measured in caudal nerve, and N1 latency of somatosensory evoked potentials (SEP) were measured 75 min after injection of TRH or serum saline. SEP latencies were 28.1 +/- 0.6, 29.4 +/- 0.8, 27.8 +/- 1.1 ms, in normal, diabetic and diabetic TRH-treated groups, and NCV values were 28.1 +/- 0.8, 23.8 +/- 0.4, and 27.9 +/- 0.7 m/s respectively. NCV was significantly reduced in the diabetic group compared to normals (P < 0.05). but then improved by TRH treatment (P < 0.05). Our findings suggest that TRH has an acute effect on peripheral neuropathy in experimental streptozotocin diabetes in the rat.

Alpha-interferon and isoprinosine in adult-onset subacute sclerosing panencephalitis

We report eight patients with adult-onset subacute sclerosing panencephalitis (SSPE), of which, four were treated with oral isoprinosine and four with intraventricular alpha-interferon plus oral isoprinosine. One of the four patients treated with oral isoprinosine died within two months, and the disease progressed in three patients. Of the four patients treated with oral isoprinosine plus intraventricular alpha-interferon, one showed mild progression, one remission, and the remaining two showed stabilization. The group of patients is relatively small, but our results suggest that treatment with oral isoprinosine plus alpha-interferon is effective for SSPE.

Cerebral venous thrombosis in pregnancy: the role of protein S deficiency

We report a 20 year-old, 28 week-pregnant woman, who developed superior sagittal sinus thrombosis, associated with a decreased free protein S level. Her father, who had been a stroke victim, had also significantly lower level of protein S. In very rare cases, a congenital or acquired protein S deficiency leads to cerebral venous thrombosis. The detection of such abnormalities has major practical consequences for the long-term management of patients to prevent further thrombotic episodes.

Auditory even-related brain potentials in hyperthyroidism

Several studies based on psychometric tests have demonstrated an impairment of cognitive functions in hyperthyroid patients. Long-latency auditory event related potentials (ERPs) allow the measurement of a kind of cerebral reaction time that is unavailable to psychometric tests. However, ERPs alterations in hyperthyroidism have been investigated only in experimentally induced hyperthyroidism in healthy subjects, but no study has reported on thyrotoxic patients so far. Therefore, we investigated alterations of P300 wave latency in hyperthyroid patients before and after antithyroid treatment. ERPs were elicited in 20 untreated patients with hyperthyroidism (mean age: 27.40 +/- 2.10 years) and in 30 sex-, age- and education-matched controls. ERPs recordings were repeated 4 months after attainment of euthyroidism. Untreated patients had longer mean P300 latencies when compared to those in controls (338.3 +/- 26.6) vs 320.7 +/- 16.2 msec, P = 0.020). Slowing of P300 latency was marked in 4 of 20 patients and its normalization was observed after treatment. The mean P300 latencies also returned to normal (320.5 +/- 15.5 msec) 4 months after achievement of euthyroidism. Our study shows that P300 is normal in most cases, while we have found in a subgroup of patients a small but statistically significant slowing. However, these alterations are reversed 4 months after attainment of euthyroidism.

A case of Addison's disease associated with the Lambert-Eaton myasthenic syndrome

Nonneoplastic Lambert-Eaton Myasthenic Syndrome (LEMS) is rare. A 27-year-old man as initially having the diagnosis of Addison's disease was admitted to the hospital because of fatigue, dry-mouthness and proximal limb weakness for 1 year. A diagnosis of LEMS was made from electrophysiological studies. Clinical and laboratory studies revealed no malignancy. We report the first case of Addison's disease associated with non-neoplastic LEMS. It is possible that subclinical LEMS might be present in patients with Addison's disease more frequently than currently believed, since the prominent symptoms of LEMS may be confused with symptoms of Addison's disease.

Isaacs' syndrome associated with chronic inflammatory demyelinating polyneuropathy

We report the first case of Isaacs' syndrome in which an inflammatory demyelinating neuropathy was documented histologically. For 9 months, the patient developed slowly progressive weakness, muscle spasms and stiffness, fasciculations, and myokymia in the arms, which were unmodified by sleep. Nerve conduction studies showed multifocal motor conduction block, abnormal dispersion phenomenon, and abnormal sensory and mixed nerve conduction. Needle electromyogram showed continuous motor unit potentials at rest with bursts of rapid-firing discharges which were unaffected by spinal anesthesia but diminished by peripheral nerve block and completely abolished by local curarization. Sural nerve biopsy demonstrated an inflammatory demyelinating neuropathy. Muscle cramping, twitching, and stiffness responded to phenytoin. The patient's weakness gradually responded to prednisone and azathioprine. Over a 17-year period, the patient had three relapses which were well controlled with prednisone and azathioprine. At this time, the patient is symptom-free without any medication.

Multifocal demyelinating motor neuropathy: pathologic evidence of 'inflammatory demyelinating polyradiculoneuropathy'

We report a case of multifocal demyelinating motor neuropathy in a patient with a 5-year history of progressive, asymmetric, predominantly motor weakness characterized by multifocal progression, multifocal conduction block, and lack of response to steroid therapy. Neuropathologic findings at autopsy showed an "inflammatory demyelinating polyradiculoneuropathy" in the motor cranial nerves and motor roots of peripheral nerves, an extensive deposition of IgG and focal accumulations of IgM in the peripheral nerve motor roots, and loss of motor neurons. These findings clearly document an inflammatory demyelinating polyradiculoneuropathy in multifocal demyelinating motor neuropathy, suggesting a close relation with chronic inflammatory demyelinating polyneuropathy.