Occupational allergic rhinitis in Finland.

Between 1980 and 1987 a total of 166 patients were diagnosed as having occupational (mostly allergic) rhinitis at the Institute of Occupational Health. This is about 20% of all the diagnosed cases in Finland. The most common causes were: flour (50 cases), wood dust (30 cases), animal epithelia (19 cases), and natural fibers, mainly cotton (19 cases). Between 1981 and 1987 the number of cases of occupational rhinitis in all of Finland more than doubled (from 61 to 128 cases per year), and in 1991 a total of 319 cases were detected. This was mainly due to the increase in rhinitis caused by animal epithelium and flour dust, which were then the most common causes of occupational rhinitis in Finland. This increase, in turn, was based on changes in the Finnish legislation, which in 1982 was extended to cover farmers. Other causes of the increase were probably the increased awareness of the public and health personnel, but a true increase in occupational rhinitis cannot be excluded.

Electronystagmographic findings among 127 dizzy patients: correlation with the aetiology of dizziness.

Electronystagmography (ENG) was performed on 127 dizzy patients and the findings were compared with the diagnosis obtained with a comprehensive neurological test battery. ENG was found to be abnormal in 49 (39%) of the patients: 19 with unilateral vestibular hyporeactivity, eight with directional preponderance, 12 with spontaneous or undirectional positional nystagmus, eight with abnormal smooth pursuit, and 13 with other abnormalities. Among the patients with abnormal ENGs, established central nervous system lesions were found in 28 cases (19 of these infratentorial lesions); nine peripheral vestibular lesions and five undefined vestibular lesions were found. Patients with normal ENGs showed fewer peripheral vestibular lesions and more dizziness of psychogenic aetiology. Almost half the patients with infratentorial lesions had normal ENGs. Patients with rotatory vertigo had fewer ENG abnormalities than those with other types of dizziness. These results suggest that ENG alone is of limited value in the diagnosis of dizziness. A comprehensive test battery is needed to establish the diagnosis.

Occupational exposure to solvents and cerebellar, brainstem and vestibular functions.

Forty-eight persons (age 44, SD 9 years) exposed to paint solvents and 40 nonexposed referents (age 45, SD 9 years) were examined. The duration of exposure was 4 to 30 (mean 20) years and the life-time exposure level was estimated to have been 10 to 330 (mean 60%) of the hygienic standard. The methods used were a neurological examination, electroencephalography, brainstem auditory-evoked potentials, electronystagmography, and posturography. Life-time exposure was estimated on the basis of a detailed occupational history and environmental measurements made at the work places over several years. The average weekly alcohol consumption was established in a detailed interview. Due to the small number of subjects examined, the study was inconclusive. The findings classified as abnormal were slightly more common in the exposed than in the referents, and in the persons who used alcohol than in the non-users. The differences were not statistically significant, and no exposure-response relationships were found.

Diagnostic value of electroencephalography and brainstem auditory evoked potentials in dizziness.

Electroencephalogram (EEG) and brainstem auditory evoked potentials (BAEP) were recorded from 142 dizzy patients. The results were compared with those obtained by other neurological examinations of the same patients. Thirty-three percent (N = 44) of the patients had an abnormal EEG: 21% (28) showed focal abnormality, 12% (16) irritative features, and 10% (13) generalized disturbance. There were no differences in the distribution of abnormal EEGs in different diagnostic categories of dizziness, but irritative findings were not found in the cases of peripheral vestibular or psychogenic disturbances. EEG findings in 3 patients suggested temporal epilepsy, correlating with the clinical picture. BAEPs were abnormal in 18% (N = 21) of the recordings. There were 3 cases of MS and 5 ischaemic lesions in the vertebro-basilar region. Twelve of the 13 other patients with abnormal BAEP showed evidence of CNS pathology with other methods. EEG abnormalities were mostly non-specific; however, the irritative findings suggested cerebral pathology, such as epilepsy. An abnormal BAEP offers reliable evidence for brainstem lesion and is thus a useful examination in dizziness.

Occupational allergic rhinitis from guar gum.

Three cases of allergic rhinitis from a vegetable gum, guar gum, have been detected. Two subjects were exposed to fine guar gum powder (Emco Gum 563, Meyhall Chemical AG, Switzerland), an insulator in rubber cables, when opening cables in a power cable laboratory. After 1-2 years' exposure the patients developed rhinitis. Scratch-chamber tests, nasal provocation tests, nasal eosinophilia and a RAST test proved their allergy. A third subject developed allergic rhinitis from another guar gum product (Meyproid 5306, Meyhall Chemical AG) after 2 years' exposure in a paper factory. A positive skin test and nasal provocation test confirmed the diagnosis. A fourth case of possible allergy to guar gum after exposure to Meyproid 5306 in a paper factory is also presented. No final diagnosis was reached in this case (in 1974). The present subjects, only one of whom was atopic, developed allergy within 2 years, although their exposure to guar gum was not especially heavy. Therefore, when handling guar, adequate ventilation facilities should be provided and protective clothing, including a respiratory mask, should be worn.

Postural body sway and exposure to high-energy impulse noise.

Detailed neurological and audiological examinations and body-sway measurements with a stable platform were carried out on 60 subjects who had been exposed to high-energy intermittent noise from firearms and had various degrees of noise-induced hearing loss. The results were compared with those for 115 healthy controls. The exposed subjects showed significantly more body sway, estimated as movement of the centre of gravity in the horizontal plane, than the controls. This swaying correlated poorly with the recalled level of noise exposure, though subjects with more severe hearing loss (by audiometric deterioration of high-frequency sound, 4 kHz and 6 kHz) showed more sway than those with less severe hearing loss. Age was not significantly correlated with body sway among the controls but men seemed to sway more than women. These results suggest subclinical disturbance of the vestibular system among subjects with impulse-noise-induced hearing loss.

Effects of xylene and alcohol on vestibular and visual functions in man.

Ten healthy male volunteers were exposed for 4 h to two concentrations [6 and 11.5 mumol/l (636 and 1,218 mg/m3)] of m-xylene or/and given single doses (0.4 and 0.8 g/kg) of ethyl alcohol. Exposure to two xylene concentrations combined with the higher dose (0.8 g/kg) of alcohol was also conducted. Vestibular functions (positional nystagmus with electronystagmography, body balance) and visual function (flicker fusion) were measured. Both alcohol doses increased body sway and the intensity of nystagmus more than either concentration of xylene did, but they had little effect on visual functions. The effects of alcohol on vestibular functions were dose-dependent. The effects of xylene alone on the vestibular system were rather small, and those on the visual functions negligible. The combined effect of alcohol and the lower concentration of xylene (6 mumol/l) on body sway was additive, but the higher xylene concentration (11.5 mumol/l) antagonized the effect of alcohol on body sway and positional nystagmus. Two subjects experienced nausea and vomited exposure to alcohol and the higher xylene concentration. Mild impairment in visual functions was noted in the combined exposure. Alcohol significantly increased the blood m-xylene concentrations, a finding that suggests that their antagonism was pharmacodynamic rather than pharmacokinetic.

Allergy to coriander. A case report.

After 3 years of occupational exposure to powdered coriander - a spice - a woman developed respiratory symptoms of immediate hypersensitivity. Skin tests, nasal and bronchial challenge tests and the RAST were positive to coriander. Column chromatography, enzymatic digestion of the fractions and skin testing suggested that the allergen is a protein.