[Symptoms and clinical course in carpal tunnel syndrome]. / Symptomer og kliniske forløp ved karpaltunnelsyndrom.

BACKGROUND: We wanted to study the symptoms in carpal tunnel syndrome, evaluate postsurgical median nerve recovery in elderly patients compared to younger patients, and investigate the clinical development and median nerve changes in non-operated cases. MATERIAL AND METHODS: The study included 92 patients diagnosed with carpal tunnel syndrome on the basis of clinical symptoms and neurophysiological findings. Neurophysiological data from elderly operated (70-89 years), younger operated (30-69 years) and non-operated (25-83 years) patients were analysed separately. RESULTS: The most common symptoms were paresthesia in the third (97%) and second (88%) digits, nocturnal paresthesia (88%), increased symptoms when at work (78%), and pain in the hand (72%). Paresthesia in the entire hand (30%) and pain in the entire arm (55%) were common. Median nerve recovery in the elderly patients was comparable to the results in the younger operated patients. Some patients recovered clinically with normalisation of the median nerve without surgery. INTERPRETATION: Carpal tunnel syndrome will often have symptoms outside the median nerve territory. Elderly patients should be operated on the same indications as those applied to younger patients. Patients with no neurological findings may be monitored without surgery.

[EEG after sleep deprivation in patients with suspected epilepsy]. / EEG etter søvndeprivering hos pasienter med epilepsisuspekte anfall.

BACKGROUND: The purpose of this study was to investigate to what extent sleep deprivation provokes epileptiform discharges in EEG in patients with suspected epilepsy. MATERIAL AND METHODS: Data from 189 adults and children with unspecified seizures who had had EEG after sleep deprivation were evaluated retrospectively. Previous standard EEGs were without epileptiform discharges. The patients' final diagnosis were collected from the medical records. RESULTS: 13% of the patients demonstrated epileptiform activity in their sleep deprivation EEG, and significantly more epileptiform activity was found in patients with generalized tonic-clonic seizures and absences. None of the patients with a history of syncope showed epileptiform activity. The activation rate was higher in patients with an abnormal standard EEG compared to those with a normal standard EEG. The sensitivity of sleep deprivation EEG in this study was 35%, specificity 98% and positive predictive value 92%. INTERPRETATION: Sleep deprivation EEG seems to have greatest diagnostic value in patients with generalized tonic-clonic seizures, absences and abnormal standard EEG.

[New drugs in the treatment of advanced colorectal cancer]. / Nye medikamenter i behandlingen av avansert kolorektalcancer.

BACKGROUND: Colorectal cancer is one of the leading cancers in industrialised countries in terms of incidence and mortality. Advanced colorectal cancer has traditionally been treated with 5-fluorouracil, alone or in combination with leucovorin. This treatment has shown response rates of 10-25%; however, little effect has been observed on survival. MATERIAL, METHODS AND RESULTS: In recent years, a number of new drugs for advanced colorectal cancer have been developed and tested. We have made a comprehensive survey of the literature and find that phase II and phase III clinical studies show improved response rates compared to the traditional use of 5-fluorouracil and leucovorin. Thymidylate-synthase inhibitors, oxaliplatine and topoisomerase inhibitors, used singly or in combination, improve response rates and show a significant effect on survival in patients with metastatic colorectal disease. INTERPRETATION: Several new drugs now available in hospital treatment of metastatic colorectal cancer show improved response and increased survival compared to traditional 5-fluorouracil regimens.

[Fluorinated pyrimidines in oral treatment of advanced colorectal cancer]. / Fluorinerte pyrimidiner i peroral behandling av avansert kolorektalcancer.

BACKGROUND: For several years, fluorinated pyrimidines have been used in the treatment of advanced colorectal cancer, mainly in the form of intravenous injections of 5-fluorouracil (5-FU), alone or in combination with leucovorin. Oral treatment with 5-FU has been difficult because of high toxicity and low bioavailability. MATERIAL, METHODS AND RESULTS: Increased knowledge of the metabolism of 5-FU, reviewed in this article, has led to the development of a number of new oral drugs for the treatment of advanced colorectal cancer. Administration of prodrugs and inhibitors of 5-FU-catabolic enzymes has led to stable and high levels of active drug. Several drugs have shown promising results in new clinical trials. INTERPRETATION: New 5-FU related drugs for oral administration show results comparable to those of the cytotoxic drugs that have been administered in hospital. In the future, general practitioners could possibly treat and follow up a larger proportion of these patients.

Median nerve recovery in carpal tunnel syndrome.

We studied recovery of median nerve function in operated elderly and younger patients with carpal tunnel syndrome, compared to nonoperated patients, using neurophysiological methods. Three groups were analyzed separately: elderly operated (n = 16, aged 70 to 89); younger operated (n = 83, aged 30 to 69); and nonoperated (n = 52, aged 25 to 83). The elderly operated patients had significant improvement after surgery in all sensory nerve variables and a decrease in motor distal latency. The results were comparable to the results in the younger operated patients. In the nonoperated hands, the same neurophysiological variables were also significantly improved, but to a lesser extent than in the operated hands. Overall symptom relief was better in the operated hands.

Systemic and local silver accumulation after total hip replacement using silver-impregnated bone cement.

In a patient, at revisional Christiansen total hip arthroplasty, silver-impregnated bone cement was used as prophylaxis against deep infection. Five years later the patient developed serious neurological deficits, and the prosthesis was loose. The loose Christiansen prosthesis and the silver-impregnated bone cement were removed and a Charnley prosthesis inserted. Intra-operatively the concentration of silver in fluid drawn from the hip joint was assessed to be about 1000 times the normal serum reference value, and tissue samples from the acetabulum were densely impregnated with silver. During the following 2 years the serum concentration of silver decreased from more than 60 times to 20 times the normal; simultaneously the patient partially recovered from her grave muscle paralysis.

[Acute and chronic effects of deep diving on the nervous system]. / Akutte og kroniske effekter på nervesystemet ved dypdykking.

Diving deeper than 180 metres of seawater (msw) will impose neurological symptoms in most divers. Atactic signs and abnormal EEGs were found in five of 18 divers immediately after deep diving. Neuropsychological testing before and after deep diving in 64 divers revealed a reduction in autonomic reactivity (48%), increased hand tremor (27%) and impairment of spatial memory and reduced finger coordination (8%) after the dives. These results had not improved one year later. A follow-up study of 40 divers one to seven years after their last deep dive revealed that the divers experienced more problems of concentration and paresthesia in feet and hands than the controls. Two had had seizures, one had suffered episodes of transitory cerebral ischemia and one had experienced transitory global amnesia after the deep dives. In the future, oil installations at depths below 180 msw should be installed and maintained with remote control and robot technology.

Visual evoked and brain stem auditory evoked potentials in divers.

Visual evoked potentials (VEP) were examined in 14 divers during dives to 360 metres of seawater (msw). All latencies increased significantly with depth. VEP and brain stem auditory evoked potentials (BAEP) were similarly examined in 18 divers before and after these dives. N75 was significantly increased after compared to before the dive, while there was no significant difference in the P100 and N145 latencies. BAEP I-V latency was significantly decreased after the dives. VEP and BAEP were examined in 156 divers and 99 controls. There was no significant difference in VEP. BAEP I-III interpeak latency was significantly increased for the divers, but with no significant changes in I-V and III-V latencies. VEP and BAEP were examined in 26 divers after treatment for neurological decompression sickness. There was no significant difference compared to the control group. The conclusions are that VEP and BAEP change transitorily with influence of hyperbaric pressure, but do not measure major permanent disturbances in the divers' visual and auditory pathways.

Electroencephalography, evoked potentials and MRI brain scans in saturation divers. An epidemiological study.

One hundred and fifty-six air and saturation divers, mean age 33.6 (range 21-49) years, were examined. The control group consisted of 100 offshore workers and policemen with the health requirements to have a diving certificate, mean age 34.0 (range 22-48) years. The examination protocol included electroencephalography (EEG), visual evoked potentials (VEPs), brain-stem auditory evoked potentials (BAEPs) and magnetic resonance imaging (MRI) of the brain and brain-stem. Abnormal EEGs, with focal slow waves mostly in the temporal regions and sharp potentials, were found in 18% of the divers and in 5% of the controls (P = 0.003). Abnormal EEGs correlated significantly with the exposure to saturation diving (P = 0.0006) and the prevalence of decompression sickness (P = 0.0102). Alcohol consumption was negatively correlated with abnormal EEGs (P = 0.0006). Mean I-III BAEP latency was increased (P = 0.047) in the diver group. P100 VEP latency decreased with age (21-49 years). High signal intensity changes obtained by MRI were found in 33% of the divers and in 43% of the controls (P = 0.14). It is concluded that the nervous system of saturation divers is influenced by their occupation and that EEG is a useful method in the health examination of divers.

[Neurological decompression sickness]. / Neurologisk trykkfallsyke.

We have examined 34 divers, mean age 30 years, after treatment for neurological decompression sickness. The initial symptoms often indicated mild sensory or motor involvement. After recompression treatment five of 19 divers with primary affection of the brain had slight hemiparesis or dysphasia. Nine of 14 divers with primary affection of the spinal cord showed signs of spinal cord dysfunction following treatment. Only 16 divers were recompressed within six hours after start of the neurological symptoms. It is concluded that neurological decompression sickness is a serious disorder with a high rate of residual findings. The condition should be treated with prompt recompression, administration of oxygen, and intravenous fluid.

Neurological long term consequences of deep diving.

Forty commercial saturation divers, mean age 34.9 (range 24-49) years, were examined one to seven years after their last deep dive (190-500 metres of seawater). Four had by then lost their divers' licence because of neurological problems. Twenty seven (68%) had been selected by neurological examination and electroencephalography before the deep dives. The control group consisted of 100 men, mean age 34.0 (range 22-48) years. The divers reported significantly more symptoms from the nervous system. Concentration difficulties and paraesthesia in feet and hands were common. They had more abnormal neurological findings by neurological examination compatible with dysfunction in the lumbar spinal cord or roots. They also had a larger proportion of abnormal electroencephalograms than the controls. The neurological symptoms and findings were highly significantly correlated with exposure to deep diving (depth included), but even more significantly correlated to air and saturation diving and prevalence of decompression sickness. Visual evoked potentials, brainstem auditory evoked potentials, and magnetic resonance imaging of the brain did not show more abnormal findings in the divers. Four (10%) divers had had episodes of cerebral dysfunction during or after the dives; two had had seizures, one had had transitory cerebral ischaemia and one had had transitory global amnesia. It is concluded that deep diving may have a long term effect on the nervous system of the divers.

Influence of occupational diving upon the nervous system: an epidemiological study.

Neurological signs and symptoms were recorded from 156 air and saturation divers and 100 controls. Fifty one (33%) of the divers had had symptoms from the central nervous system during decompression. Also, 22 (14%) had been unconscious while diving. In total 79 (51%) had had decompression sickness (DCS). Twelve (8%) of the divers and no controls had had specific neurological symptoms (vision disturbances, vertigo, reduced skin sensitivity) in non-diving situations, and six (4%) of the divers (no controls) had had episodes of cerebral dysfunction (seizures, transient cerebral ischaemia, transient amnesia). The divers had significantly more general symptoms from the nervous system and more abnormal neurological findings than the controls. The most prominent symptoms were difficulties in concentration and problems with long and short term memory. The most prominent abnormal findings in the divers were compatible with dysfunction in the distal spinal cord or nerve roots, and polyneuropathy. The general neurological symptoms and findings were independently significantly correlated with diving exposure, prevalence of DCS, and age.

Analysis of neurologic symptoms in deep diving: implications for selection of divers.

Eighteen professional divers (age range 24-33 yr, mean 28.3) participated in one simulated dive to 360 meters of seawater (msw) in a helium-oxygen (heliox) atmosphere with equal compression and decompression profiles. All divers were given an extensive neurologic examination before diving. Clinical neurologic symptoms observed during the dives were equilibrium disorder, sleep disturbances, fatigue, nausea, loose stools, stomach pain, tremor, mental disturbances, reduced appetite, and headache. Symptoms were scored individually by each diver. The symptoms were analyzed statistically by factor analysis, which grouped them into four factors. These symptoms are presumably related to functional disturbances in the brain stem and the cerebellum. Factor 3 symptoms (tremor, mental disturbances, reduced appetite) correlated significantly to a history of predive decompression sickness (P = 0.006) and to cerebral concussion (P = 0.023). Three divers were periodically unable to work at bottom due to equilibrium disorder, diarrhea, or nausea. One diver with mild polyneuropathy and slight cerebral atrophy as seen by computerized tomography and another diver with abnormal electroencephalography were periodically unable to work due to equilibrium disorder and nausea, respectively. We advocate that divers with signs of central or peripheral nervous system dysfunction should not be selected for deep diving.

Cerebellar lesion, polyneuropathy and mental dysfunction in a seaman working on chemical tankers.

A seaman with symptoms and signs from the nervous system was examined. He had symptoms and signs of affection of his mental status, cerebellum and peripheral nerves. He had been working on tankers for 31 years, and had regularly been exposed to different organic solvents during loading, unloading and cleaning of the tanks. As no other disease was present in this patient, the existence of a chronic organic solvent intoxication syndrome was suggested.

Immediate neurological effects of diving to a depth of 360 metres.

Eighteen divers performed a simulated dive to a depth of 360 metres of seawater breathing a mixture of helium and oxygen. Clinical neurological examinations and neurophysiological tests were performed before and after the dives. Two divers had mild ataxic signs and changed electronystagmography after the dive, and one had impaired vibration sense in one lower extremity. Abnormal EEGs with slow waves and sharp potentials, seen primarily in the temporal regions, occurred in 2 divers. No changes were found in the magnetic resonance imaging brain scans. The divers with evidence of previous central nervous system injury, or a history of unconsciousness or previous decompression sickness seemed more likely to develop neurological signs after these deep dives. This study shows that deep diving may induce immediate neurological changes. We recommend that future deep divers have a neurological examination and 2 separate EEGs included in their medical examinations.

The non-linear relationship between nerve conduction velocity and skin temperature.

Median motor and sensory nerves were examined in 20 healthy subjects. Superficial stimulating and recording electrodes were used, and the nerves were examined at natural skin temperature, after cooling and after heating of the arm. The conduction velocity for the fastest and slow conducting sensory fibres (temperature range 17-37 degrees C), and for the fastest conducting motor fibres (temperature range 19-38 degrees C) increased non-linearly with increase in skin temperature. Similarly, distal motor latencies increased non-linearly with decrease in skin temperature. The effect of temperature was most pronounced in the low temperature range, and change in conduction velocity per degree centigrade was reduced toward higher skin temperature. Sensory nerve response duration increased linearly with decline in skin temperature. Sensory and motor amplitude did not show any significant relation to skin temperature.

Nerve conduction velocity in man during deep diving to 360 msw.

The function of the sensory and motor median nerves was examined in 6 divers during a simulated dive to 360 meters of seawater (msw), with a mixture of helium and oxygen (heliox) as breathing gas. Divers were examined in the compression chamber before the dive, at 360, 300, 240, 130, 50, and 5 msw, and with skin temperatures ranging from 29.2 degrees to 35.2 degrees C. Examinations were performed with superficial stimulating and recording electrodes. Fast sensory nerve conduction decreased with increase in hyperbaric pressure and with decrease in skin temperature. There was no significant correlation between slow sensory conduction and hyperbaric pressure. Distal motor latency increased with increase in hyperbaric pressure and with decrease in skin temperature. The effect of pressure was independent of temperature. No significant functional changes were detected in the main nerve trunk proximal to the wrist or in the F-wave responses.

Seamen exposed to organic solvents. A cross-sectional study with special reference to the nervous system.

A cross-sectional study of 85 long-term solvent exposed seamen working on chemical tankers compared to 59 unexposed seamen. Symptoms from the nervous system, clinical neurological findings and neurographic measurements were studied. The examinations were performed at least 2 weeks after the last solvent exposure. A stepwise multiple regression analysis was used to evaluate the dose-response relationship between the registered data on one hand and solvent exposure, employment on chemical tankers, age, alcohol and chloroquine phosphate consumption on the other. A significant correlation was found between increasing solvent exposure and reduced sensory nerve conduction velocities, as well as between increasing solvent exposure and prolonged distal latencies of motor nerves, and between increasing exposure and reduction of action potential amplitudes of sensory nerves. No correlation was found between solvent exposure and symptoms from the nervous system or clinical neurological findings.