Biomedical subjects
Publications and source records attributed to S J Oh.
Comprehensive electrophysiological studies were performed on 13 patients with arsenic neuropathy. The most prominent finding was a marked abnormality in sensory nerve conduction in the presence of moderate abnormalities in motor nerve conduction. The motor nerve conduction studies and needle EMG were typical of those seen in axonal degeneration which was confirmed by sural nerve biopsy.
Creutzfeldt-Jakob disease (CJD) is presumably caused by a slow infectious pathogen or prion. The principal clinical features of Creutzfeldt-Jakob disease are dementia, pyramidal and extrapyramidal symptoms and signs, cerebellar dysfunction, and myoclonus. The patient rapidly deteriorates, declines to a vegetative state, becomes comatous, and is ultimately dead within several months. The authors present a case of Creutzfeldt-Jakob disease, proved by clinical findings, typical serial EEG, and pathologic features.
Uneqivocally positive edrophonium tests, both clinically and electrophysiologically, were observed in a classic case of the Lambert-Eaton myasthenic syndrome. A review of the literature revealed that a positive edrophonium response has been reported in a majority of cases of myasthenia gravis (MG) and overlap myasthenic syndrome and in some cases of the Lambert-Eaton myasthenic syndrome, botulism, congenital myasthenic syndrome, drug-induced myasthenic syndrome, the Guillain-Barre syndrome, and amyotrophic lateral sclerosis. From this, we conclude that an unequivocally positive edrophonium test alone is not necessarily diagnostic of MG and that the diagnosis of MG should be based on the clinical features together with edrophonium-responsiveness and other laboratory findings.
We present electrodiagnostic data on 30 patients with inclusion body myositis (IBM) in order to better delineate its electrophysiological features. Comprehensive electromyography (EMG) and nerve conduction studies (NCS) were performed in all cases. Twelve patients had single fiber electromyography (SFEMG). EMG showed abundant short-small motor unit potentials (MUP) with fibrillations and positive sharp waves in 56.6% of patients, and a mixed pattern of large and small MUP in 36.7%. In 6.7%, only "neurogenic" features were seen. NCS were slow in 33.3%. SFEMG revealed a mildly abnormal jitter and a slightly increased fiber density. IBM demonstrates a heterogeneous EMG profile. A pattern of large and small MUP is highly suggestive of IBM but is seen in only about one third of cases.
A 74-year-old man had a paraneoplastic motor neuron disease mimicking amyotrophic lateral sclerosis. He had an elevated erythrocyte sedimentation rate, other laboratory abnormalities, and a previously undiagnosed renal cell carcinoma. Four months after nephrectomy, his strength had improved and he had no fasciculations. Seven other patients with cancer and motor neuron disease improved or stabilized after tumor treatment. Even though it is rare, paraneoplastic motor neuron disease is important to diagnose because it may be treatable.
In recent years, the sural nerve biopsy has become a commonly performed procedure in the diagnostic work-up of patients with peripheral neuropathy. This paper reviews the diagnostic usefulness and limitations of this procedure. Based on 385 sural nerve biopsies, we found clinically helpful or relevant information in 45% of cases. In 24% of cases, specific diagnoses were obtained, among which vasculitic neuropathy was most common.
Sensory nerve conduction velocity (SNCV) over the forearm segment of the superficial radial nerve was studied by an antidromic method in 76 nerves of 50 normal volunteers ranging in age from 16 to 70 years. The mean SNCVs were 53.3 +/- 3.6 m/sec (1 SD) and the mean amplitudes of sensory nerve action potentials were 15.2 +/- 9.8 microV (1 SD). This method of obtaining SNCV over the forearm segment of the superficial radial nerve is easily performed and the findings are consistent.
Posterior antebrachial cutaneous (PABC) neuropathy is rare. Two original cases are reported here. In case 1, the neuropathy is probably due to a traction injury in a reduction operation for humeral fracture. In case 2, it is injured associately with an operation in taking a myocutaneous flap. On examination, both cases showed a decreased sensation to pin-prick over the PABC nerve territories and a positive Tinel's sign near the injured sites. Sensory nerve conduction study of the PABC nerves revealed a low amplitude of the compound nerve action potential (CNAP) and a slow sensory nerve conduction velocity (SNCV) in case 1, and absent CNAP in case 2. Our study showed the sensory nerve conduction test is useful in confirming PABC neuropathy.
Tomaculous neuropathy (TN) is classically associated with the inherited, recurrent focal neuropathies. We report a case of TN manifesting as an acute recurrent polyneuropathy. A 28-year-old woman had 2 episodes of acute, ascending, symmetrical sensorimotor deficit. Teased nerve-fiber preparation confirmed the presence of TN. Extensive investigations failed to reveal other cause for her symptoms. We believe that this case is unique and broadens the clinical spectrum of TN.
Since the popularization of routine creatine kinase (CK) measurement, an increasing number of patients with unexplained CK elevation ("asymptomatic hyper-CK-emia") are being identified. We studied 19 patients with persistent CK elevation of unknown etiology with electromyography (EMG) and muscle biopsy. Needle EMG was abnormal in 14 patients. Muscle biopsy was positive in all individuals with abnormal EMG and in one patient with normal EMG. Diagnoses included polymyositis in five patients, morphologically nonspecific myopathy in three, mitochondrial myopathy in two, and sarcoid myopathy, central core disease, multicore disease, inclusion body myopathy, and McArdle's disease in one case, respectively. Five patients with abnormal biopsies developed weakness within 1 year of presentation. We conclude that persistent asymptomatic CK elevation represents mild or early myopathy in a majority of cases.
Various parameters of single- fiber electromyography (SFEMG) were studied in 19 patients with electrophysiologically and histologically proven chronic demyelinating neuropathy. The mean duration of disease at the time of testing was four years. Motor nerve conduction in the median nerve was abnormal in all patients, whereas sensory nerve conduction was abnormal in all but one. Needle EMG in the extensor digitorum communis (EDC) muscle showed rare fibrillations and fasciculations and some abnormal motor unit potentials in most of patients. SFEMG in the EDC muscle showed an increased fiber density in seven cases (37%) and minimally abnormal jitter in 14 cases (74%). Single-fiber action potentials were stable, whereas blocking was rare. Fiber density was significantly increased in patients with fibrillation in the conventional needle EMG. Our study showed that the SFEMG is mildly abnormal in many patients with demyelinating neuropathy and that this test is useful in detecting and quantitating axonal degeneration in demyelinating neuropathy.
Among 13 patients with the Lambert-Eaton myathenic syndrome (LEMS), three different patterns on the repetitive nerve stimulation test were observed at the time of initial testing. Type 1 pattern, seen in one patient, had low normal CMAP amplitude, decremental response at the low rate of stimulation (LRS), and relatively normal response at the high rate of stimulation (HRS). Type 2, seen in nine patients, had the classical triad: low CMAP amplitude, decremental response at LRS, and incremental response at HRS. Type 3, seen in three patients, showed low CMAP amplitude, decremental response at LRS, and initial decremental response at HRS. We believe that these three patterns represent different degrees of blocking in LEMS, from the mildest in type 1 to the most severe in type 3. Since types 1 and 3 can be misinterpreted as myasthenia gravis patterns, they must be recognized in LEMS and an incremental response documented by prolonged stimulation at HRS.
In two patients with the Lambert-Eaton myasthenic syndrome (LEMS) and small-cell lung carcinoma (SLLC), therapy for LEMS was effective when combined with cancer therapy. The serial SFEMG tests showed a corresponding improvement with remission of the LEMS and proved to be a better and earlier indicator of the changing clinical status than the repetitive nerve stimulation test. Thus, we conclude that the SFEMG is useful in the follow-up evaluation of patients with this condition.
A patient who had always lived in the United States had an HTLV-I infection and a chronic myelopathy clinically mimicking amyotrophic lateral sclerosis. Needle EMG and nerve conduction studies were consistent with anterior horn cell disease but muscle biopsy showed denervation and an inflammatory myopathy. Serum HTLV-I antibody tests were positive and HTLV-I DNA was present in peripheral leukocytes. This is the 1st reported US native with HTLV-I-associated myelopathy and polymyositis.
A patient with small-cell lung carcinoma and the Lambert-Eaton myasthenic syndrome had circulating neuronal antinuclear antibodies. Serum stained the nuclei of all neurons in sections of human brain and identified a closely spaced group of 33-39 kDa proteins in immunoblots of human neuronal nuclei. These autoantibodies are indistinguishable from those recently identified in patients with paraneoplastic subacute sensory neuronopathy.
We are reporting the first case of posterior antebrachial cutaneous (PABC) neuropathy which was confirmed by the sensory nerve conduction test. PABC neuropathy and radial nerve palsy developed after an intramuscular injection in this case. Sensory nerve conduction study of the PABC nerve showed slow nerve conduction velocity but normal amplitude of compound nerve action potential (CNAP). Follow-up testing revealed an increase in the CNAP amplitude and normalization of nerve conduction velocity in the PABC nerve. Our study demonstrates that PABC neuropathy can be confirmed by the sensory nerve conduction test.
Explore the source record for details and available documents.
Explore the source record for details and available documents.