Analysis of meteorologic variables and seasonal aeroallergen pollen counts in Denver, Colorado.

BACKGROUND: The observation of low levels of weed pollens following a freeze and an early autumn snowfall in Denver, Colorado led to this analysis of meteorologic variables and pollen counts. OBJECTIVE: The purpose of this study was to examine, in depth, the relationship between observed pollen counts and a selection of independent meteorologic variables. METHODS: We prospectively studied in 1991 daily high and low temperature, relative humidity, precipitation, barometric pressure, percent sunshine, wind velocity and direction, tree, grass, and weed pollen, as well as dates of the first frost/freeze. Similar data were retrospectively analyzed for 1987-1990. RESULTS: Correlation coefficients for the prospective data were as high as .611 for high temperature and cottonwood and .718 for high temperature and maple (P < .001). High and low temperature showed strong correlations with the combined weed counts (.598 and .628, respectively, P < .001). CONCLUSIONS: Denver weed pollens appear impacted more by temperature and less by precipitation and humidity, while the converse is true for tree and grass pollen. However, weed pollen, especially sage, may appreciably rebound after freezing temperatures. While separate meteorologic variables may have high correlations with specific pollen counts in a given year, such effect is not consistent and varies from year to year.

Spectrum of presentation of paradoxical vocal cord motion in ambulatory patients.

BACKGROUND: Paradoxical vocal cord motion (PVCM) frequently masquerades as asthma. Atypical presentations of asthma or situations in which asthma does not respond to traditional therapies mandate the consideration of PVCM in the differential diagnosis. OBJECTIVE: Evaluate the demographics and spectrum of presentation of PVCM in an ambulatory outpatient population. METHODS: Retrospective survey of medical records of 164 consecutive patients (86 males, 78 females) who underwent fiberoptic rhinolaryngoscopy over a 3-year period. RESULTS: Twenty patients (16 females, 4 males) with PVCM diagnosed by direct visualization were identified. Mean age at diagnosis was 33 years (range, 14-58 years). Asthma was the most common presenting diagnosis (15/20, 75%), while the remaining 25% had other unusual presentations including two patients (10%) with PVCM masquerading as anaphylaxis. When PVCM masqueraded as asthma, 44% of those patients were inappropriately treated with oral steroids. Nine patients (45%) had a readily identifiable psychologic trigger of their PVCM. CONCLUSIONS: Our data confirm previous observations indicating that PVCM is most common in young females and is often associated with psychologic problems. PVCM frequently masquerades as asthma, resulting in overtreatment with corticosteroids. PVCM may also masquerade as stridor, resulting in mimicry of anaphylaxis in the appropriate clinical setting. Thus, PVCM should be considered in any patient presenting with atypical upper and lower respiratory tract symptoms.

Chronic urticaria exacerbated by the antioxidant food preservatives, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT).

Two patients with chronic idiopathic urticaria in whom remissions were achieved with dye- and preservative-elimination diet had exacerbations of their urticaria when they were challenged under double-blind, placebo-controlled conditions with butylated hydroxyanisole and butylated hydroxytoluene. After elimination of butylated hydroxyanisole and butylated hydroxytoluene from their diets, there was marked abatement of the frequency, severity, and duration of their urticaria. These antioxidants appear capable of aggravating symptoms in certain patients with chronic urticaria.

The development of subsensitivity to atropine methylnitrate. A double-blind, placebo-controlled crossover study.

This is a double-blind, placebo-controlled crossover study designed to assess the effectiveness of nebulized atropine methylnitrate (AMN) with chronic use. We studied 22 patients with asthma, 10 receiving theophylline and inhaled beta-agonists and 12 who were receiving corticosteroids as well. All had demonstrated at least a 15% change in FEV1 either spontaneously or after bronchodilator. Bronchodilator effect was measured serially for 4 h after inhalation of the initial dose and again after 2 wk of four-times-daily use. Significant bronchodilator effect was seen initially with AMN when compared to placebo (p less than 0.01). After 2 wk of use, the bronchodilator effect of AMN was significantly diminished as compared to the initial effect (p less than 0.01) but was still better than placebo (p less than 0.05). Subsensitivity did develop to varying degrees in the patients, but we were unable to identify any clinical parameters that would allow prediction of subsequent subsensitivity. We conclude that the development of subsensitivity to AMN occurs in certain patients with chronic administration but does not reflect a total loss of bronchodilator effect.