E. M. G. Joosten

Hereditary neuropathy with liability to pressure palsies: A clinical, electroneurophysiological and morphological study

Clinical, electroneurographic and myographic studies were performed on 99 patients of 13 families having hereditary neuropathy with liability to pressure palsies (HNPP) and on 116 relatives. Diagnosis was confirmed in all families by a nerve biopsy of the index case. Large focal myelin thickenings (tomacula) were found in nerve biopsies of affected persons, whether or not pressure palsies had occurred. By using three electroneurographical parameters it was possible to discriminate between asymptomatic patients and unaffected relatives. Complaints sometimes mentioned in literature as being associated with HNPP such as low back pain, brachialgia and short lasting paraesthesia are not related to HNPP. The hereditary transmission is autosomal dominant with total penetration but variable expression.

Ceroid-lipofuscinosis (Batten's disease). First ophthalmological report of cytoplasmic inclusions in the Schwann's cell of the sural nerve in two patients with an amaurotic familial idiocy.

Two patients with the clinical picture of a late infantile and juvenile amaurotic familial idiocy (Battens disease) have been examined electron microscopically. The typical cytoplasmic inclusion bodies in the Schwann cells of the sural nerve supported this clinical diagnosis. The importance of sural nerve biopsy in patients with a cerebroretinal degeneration is discussed.

The calcium homeostasis and the membrane potential of cultured muscle cells from patients with myotonic dystrophy.

Using the fluorescence indicator, quin2, we compared the cytoplasmic Ca2+ concentration ([Ca2+]i) of cultured myotubes obtained from control subjects and myotonic dystrophy (MyD) patients. In Ca2(+)-free buffer the [Ca2+]i of the cultured MyD muscle cells was not significantly different from that of the control cells. In the presence of 1 mM external Ca2+ the cultured MyD muscle cells showed a significantly higher [Ca2+]i, which was due to the influx of Ca2+ through voltage-operated nifedipine-sensitive Ca2+ channels. In the presence of external Ca2+, MyD myotubes did not respond to acetylcholine, whereas control myotubes showed a transient increase in [Ca2+]i after addition of acetylcholine. This increase was inhibited by the addition of nifedipine. The differences in Ca2(+)-homeostasis between cultured MyD muscle cells and control cells were not due to differences in the resting membrane potential or the inability of the MyD cells to depolarize as a response to acetylcholine. Therefore, cultured MyD muscle cells exhibit altered nifedipine-sensitive voltage-operated channels which are active under conditions in which they are normally present in the inactive state, and which are unable to respond to depolarization caused by acetylcholine.

Muscle cramp: Main theories as to aetiology

SummaryHistorically relevant hypotheses on the pathophysiology of muscle cramp are reviewed. Psychosomatic, static, vascular, myogenic and neural theories are highlighted from a clinicians point of view. Modern neurophysiological research leaves little doubt that true muscle cramp is caused by explosive hyperactivity of motor nerves. Several mechanisms may be involved including spinal disinhibition, abnormal excitability of motor nerve terminals and spreading of muscle contraction by ephaptic transmission or axon reflexes.

Exertional rhabdomyolysis in a patient with calcium adenosine triphosphatase deficiency.

A patient with exertional rhabdomyolysis and continuously elevated serum creatine kinase (CK) was investigated. The known causes of recurrent attacks of rhabdomyolysis were ruled out by appropriate histochemical and biochemical investigations. During ischaemic exercise tests an abnormal K(+)-efflux from exercising muscles was observed. The patient was found to have a deficiency of muscular Ca(2+)-ATPase. Dantrolene sodium therapy gave relief of muscle symptoms and improved the exercise tolerance. Both the CK level and the K(+)-efflux in ischaemic forearm testing became normal on this therapy.

The rigid spine syndrome.

Four patients are reported, 3 females and 1 male, with (as a prominent symptom of muscle disease) limitation of flexion of cervical and dorsolumbar spine. The nosological classification of these cases is discussed. In two patients there was evidence of an inclusion body myositis. At necropsy one of these patients had a remarkable distribution of muscle changes.

Electron-microscopic heterogeneity of onion-bulb neuropathies of the Déjerine-Sottas type

SummaryThe microscopic and electron microscopic findings in sural nerve biopsies of a brother and sister with chronic polyneuropathy of the Dejerine-Sottas type resemble those reported by Lyon (1969). A genetically determined variant appears to be involved.The relationship between this syndrome and onion-bulb neuropathies is discussed. It seems unlikely that only segmental demyelination and remyelination is responsible for onionbulb formation. The relationship between axons in the layers of onion-bulbs and the central fibre is discussed, and between basement membranes and Schwann cell processes and the central fibre. Significant quantitative evidence of axon degeneration and regeneration after primary axon degeneration is pointed out. Earlier probable cases in the literature are reviewed.

In vitro contraction test for malignant hyperthermia in patients with unexplained recurrent rhabdomyolysis

A few cases of non-anaesthetic-induced rhabdomyolysis in humans, predisposed to malignant hyperthermia (MH), have been described in literature. We studied a group of 6 consecutive patients with unexplained and recurrent attacks of rhabdomyolysis with the test used to determine susceptibility to MH, the in vitro contraction test (IVCT). The results of the IVCT showed 5 of these 6 patients to be MH susceptible. In cultured muscle cells from one of these patients a disturbed calcium homeostasis could be demonstrated. The relation between MH and recurrent rhabdomyolysis is discussed.

The incidence of muscle cramp.

pighian carcinoma invading the thyroid and the right wall of the trachea. He was treated with ablation of the right thyroid lobe, tracheotomy, and three courses of chemotherapy (CCDP, 5FU) followed by radiation therapy on the larynx (70 Gy) and upper mediastinum (45 Gy) with a 20 Gy dose on the sub-glottic area. The calculated total radiation dose received on the spinal cord was 48 Gy at the C6 level (maximal dose at 2 cm high). Other parts of the spinal cord received 42 Gy at the cervical region (including C7) and 41 Gy for T1. There was no development of the mass on regular CT scans. The only treatment was thyroid hormones after surgery. Three years after finishing radiation therapy and after transient parasthesia of the hands and a Lhermitte sign (lasting less than two weeks), the patient developed progressive wasting and weakness of both hands and forearm extensors. He had no symptoms in the legs nor sphincter disturbance. We found no sensory abnormality (except a questionable reduction of tactile perception on the inner side of the right hand) nor autonomic dysfunction, and tendon reflexes were present except supinator and triceps jerks on both sides. Neurological examination elsewhere was unremarkable. Electromyographic examination showed fibrillation, giant potentials and some fasciculations in right and left hand muscles, and reduced recruitment in forearm extensors. The more proximal muscles of the arms and muscles of the face and legs were normal. Motor conduction velocities, distal motor latencies, and amplitude of sensory potentials were normal in all limbs. Values of somatosensory evoked potentials were in the normal range after median and posterior tibial stimulation. Haematological, biochemical, and hepatic routine tests, thyroid hormones, lipidogram, syphilitic serology, viral serologies, serum lead and urine lead concentrations were normal. Cerebrospinal fluid was normal for cellular count, biochemistry and protein electrophoresis. Cervical MRI was performed five months after the first neurological symptoms on a 1,5 Tesla superconducting magnet (Magnetom Siemens). Two excitations and a display matrix of 256 x 256 were used; the section thickness was 4 mm. Sagittal and axial studies showed a cystic lesion with well defined borders and a signal isointense with respect to CSF on TI weighted images (TR= 500 ms, TE= 15 ms) and T2 weighted images (FIS P a= 100,TR= 100 ms,TE = 27 ms) within the spinal cord from C4 to C6 and a smaller cavity behind the body of the atlas (figure). There was no enhancement of this image after IV injection of gadolinium and the cerebellar tonsils were not in an ectopic position. The fatty replacement of spinal bone marrow due to radiation therapy accounted for the high signal intensity of the cervical spine on the same level.3 The thoracic MRI was normal. There was no change in neurological condition after eight months. This case fulfils the strict criteria established for an accurate diagnosis of radiation myelopathy4: spinal cord included in the area of radiation; principal neurological manifestations compatible with the irradiated portion of the cord; other possible aetiologies such as compression due to metastases excluded by neurological investigations; and a latent period of at least nine months before the development of symptoms. Radiation myelopathies may be divided into five main Figure Sagittal TI weighted SE (500 msl 15 ms) image showing cystic hypointense cavity affecting spinal cordfrom C4 to C6 without ectopic tonsils. Note fatty replacement of cervical spine bone marrowfrom C2 to C6, responsible for hypersignal on TI weighted

The neuropathy of Cockayne syndrome

SummaryWe studied three unrelated infants and three adolescent siblings with Cockayne syndrome. The infants showed severe psychomotor retardation. Neurologic manifestations in the siblings were less severe and only slowly progressive. All patients had slowed peripheral nerve conduction. Nerve biopsies demonstrated segmental demyelination and remyelination in each case. In the infantile cases this process was severe and rapidly progressive; in the juvenile cases it was mild and chronic. Distinctive membrane-bound polymorphous inclusions were found in occasional Schwann cells.