The immunogenicity, allergenicity, and cross-reactivity of aztreonam were investigated in 19 patients with cystic fibrosis (CF) who are allergic to beta-lactam antibiotics. Skin tests with benzyl-penicilloyl polylysine (BPO), minor determinant mixture, and the drug responsible for the previous allergic reaction were positive for 26%, 53%, and 79% of the patients, respectively. Serum IgG, but not IgE, antibodies to BPO were detected in nine of 14 patients. Eighteen patients whose skin tests with aztreonam were negative were treated. One developed bronchospasm. The others tolerated aztreonam, with an improvement in clinical score greater than or equal to 1 month after treatment (P less than .001). One patient without previous exposure had positive aztreonam skin tests and was later treated uneventfully after iv desensitization. Treatment with aztreonam did not result in IgG or IgE antibody responses in vitro. However, two patients had anaphylactic reactions on reexposure. In patients with CF, allergy to beta-lactam antibiotics is primarily drug-specific. But despite reduced immunogenicity and cross-reactivity, aztreonam should be administered cautiously to patients with CF who are allergic to other beta-lactam antibiotics because it is potentially allergenic with repeated use.

Adolescent↗

PubMedDate not supplied

Evaluation of the wheezing infant.

Wheezing is a very common symptom or sign in the infant. The evaluation of the underlying cause of the wheezing is difficult and requires a thorough assessment of several factors in the history and physical examination and a basic understanding of the pathophysiology of wheezing. With the increased availability of infant pulmonary function equipment, the evaluation of serial pulmonary function studies in infants with wheezing should prove helpful in continued assessment of the reversibility of their airway obstruction using bronchodilators and the effect of antiinflammatory pharmacologic agents on long-term hyperresponsiveness of the airways. Wheezing-associated respiratory tract infections in infancy ("wheezy bronchitis") and asthma share common risk factors, including history of exposure to environmental tobacco smoke, but the link between these two entities is still controversial. Each infant who presents with wheezing should be assessed individually with a thorough history and physical examination and an evaluation of the likelihood of asthma versus other underlying causes of wheezing such as cystic fibrosis, aspiration syndromes, congenital anomalies, or environmental factors such as exposure to passive tobacco smoking.

Airway Obstruction↗

PubMedDate not supplied

Flexible fiberoptic rhinoscopy in the diagnosis of nasal polyps in cystic fibrosis.

The incidence of nasal polyps in patients with CF in various studies varies from 6.7% to 48%. Fiberoptic rhinoscopy, a safe and minimally invasive diagnostic procedure, has the major advantage over routine physical examination of the nares because of the ability to examine the nose beyond the nasal vestibule. In examinations of both nostrils of 34 patients with CF age 4-30 years, nasal polyps were detected by rhinoscopic examination, but missed by physical examination in 17 (25%) of the nostrils. In 7% (5/64) of the nostrils in this series, rhinoscopy ruled out polyps that were reportedly identified on physician examination. This study confirms that even a careful physical examination of the nose is often inadequate to uncover significant nasal pathology such as nasal polyps.

Child↗

PubMedDate not supplied

Pharmacokinetics of high-dose azlocillin sodium in patients with cystic fibrosis.

The pharmacokinetics of high-dose azlocillin sodium was studied in 18 patients with cystic fibrosis. Nine male and nine female patients with a mean age of 14.7 years (range 3 to 29 years) participated in the study. They received azlocillin 450 mg/kg/day (as the sodium salt) in six divided doses. During a steady-state dosing interval, a dose of azlocillin was coadministered with a 10-mg/kg dose of iothalamate sodium as a 30-minute infusion. Serum concentrations of azlocillin and iothalamate were determined by high-pressure liquid chromatography assay. The data were analyzed using model-independent methods. The mean elimination rate constant for azlocillin was 0.64 +/- 0.22 hr-1 and the mean serum half-life was 1.22 +/- 0.39 hr. Total clearance of azlocillin, calculated by noncompartmental analysis, was 77.2 +/- 26.4 mL/min/sq m. Glomerular filtration rate, as estimated by measuring iothalamate clearance, was 79.6 +/- 21.9 mL/min/sq m. The total clearance of azlocillin correlated with iothalamate clearance. Patients with cystic fibrosis appear to eliminate azlocillin more rapidly than healthy individuals. This rapid elimination warrants the use of high doses to maintain high serum concentrations.

Adolescent↗