Pulmonary infiltrates with eosinophilia syndromes in children.

Pulmonary infiltrates with eosinophilia (PIE) are a group of heterogeneous disorders having the common findings of lung disease and eosinophilia in the peripheral blood, bronchoalveolar lavage fluid, or pulmonary interstitium. Eleven cases of PIE syndromes were identified through a retrospective and prospective chart review: drug-induced (2), acute eosinophilic pneumonia (3), infant pulmonary eosinophilia (2), parasite-induced (2), Churg-Strauss syndrome (1), and atypical chronic PIE (1). Patient demographics, clinical presentation, and disease severity varied considerably among groups. Therapeutic interventions included bronchodilators (10), oxygen (7), corticosteroids (9), and mechanical ventilation (3). A single patient with acute eosinophilic pneumonia died. Our experience suggests that PIE syndromes are rare in childhood and that clinical presentation can vary widely. Because of the potential for significant morbidity and mortality, aggressive diagnostic evaluations are warranted, particularly in children with respiratory failure of unknown etiology.

Abnormal ventilatory responses in patients with Prader-Willi syndrome.

Abnormal ventilatory control in patients with Prader-Willi syndrome when awake and sleeping include abnormal responses to hyperoxia, hypoxia and hypercarbia. Lindgren et al., report similar results regarding response to hypoxia; however, they have demonstrated significant minute ventilation and carbon dioxide responses in their patients treated with growth hormone irrespective of body mass index. It is possible that the explanation for the abnormal respiratory control in this syndrome is located in central rather than peripheral structures. The hypothalamus stands out as the possible location that links their abnormal ventilatory control with the other features. Further investigations to correlate this finding are warranted.

The pharmacokinetics of oral ranitidine in children and adolescents with cystic fibrosis.

The pharmacokinetics of oral ranitidine were studied in 9 patients (ages 9.9 to 19.6 years) with cystic fibrosis (CF). Patients were evaluated at steady-state conditions, and the mean maximum serum concentration (Cmax) was 845.7 +/- 448.1 ng/mL. To adjust for the variable drug dosing used among study patients, both Cmax and area under the concentration curve (AUC) were standardized to dose (CmaxST and AUCST, respectively) and were 217.9 +/- 87.9 ng/mL and 1038.0 +/- 242.2 ng/mL.h. The elimination half-life (t1/2) was 2.7 +/- 1.4 hours, and the apparent steady-state volume of distribution (Vdss) was 4.6 +/- 1.7 L/kg. The plasma clearance was 1.022 +/- 0.290 L/kg/h. The Vdss in this study was greater than that previously reported in children with peptic ulcer disease. Statistically significant relationships between pharmacokinetic parameters and measures of disease severity were not observed in the study population. The pharmacokinetics of ranitidine in children and adolescents with CF may differ from those in children and adolescents without CF.

High fever after flexible bronchoscopy and bronchoalveolar lavage in noncritically ill immunocompetent children.

Flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) have been applied increasingly to the evaluation of pulmonary disease in children. Although several complications have been reported following FB and BAL, high fever after BAL in immunocompetent children has not previously been reported. To determine the frequency, clinical characteristics, and outcome of these complications in children who developed high fever post-BAL, we retrospectively reviewed all bronchoscopic procedures done on an outpatient basis between August 1995 and July 1997. We identified 78 immunocompetent noncritically ill children who had undergone FB and BAL as an outpatient procedure for evaluation of underlying pulmonary disease, of whom 13 (17%) developed temperature (T) higher than or equal to 39 degrees C (fever group). The 13 patients in the fever group had a median age of 10 (range, 4-48) months and a reported T of 39.4 degrees C (39.1-40.6 degrees C) occurring 7.5 (4-12) hr after BAL. To determine if there were differences in clinical or BAL fluid (BALF) characteristics, we compared each child in the fever group to two children in the nonfever group, based upon primary indications and age. There were no differences in demographic or clinical characteristics between the two groups. Lymphocyte concentrations in BALF were significantly reduced in the fever group (P = 0.03). An abnormal BALF cell differential (defined as one or more of the following: neutrophils >10%, lymphocytes >30%, or eosinophils >1%) was significantly more common in the fever group (P = 0.008, odds ratio 3.6). We conclude that high fever is a frequent adverse event following BAL in noncritically ill immunocompetent children with underlying pulmonary disease. Pre-BAL clinical characteristics are not associated with development of high fever. However, the finding of an abnormal BALF cell differential is strongly associated with development of high fever post-BAL.

Short-term potentiation of ventilation after different levels of hypoxia.

Short-term potentiation of ventilation (VSTP) may be observed in healthy subjects on sudden termination of an hypoxic stimulus. We hypothesized that the level of hypoxia preceding normoxia would modify the duration and magnitude of the ensuing ventilatory decay. Ten healthy adults were studied on two different occasions, during which they were randomly exposed to isocapnic 6 or 10% O2 for 60 s and then switched to an isocapnic normoxic gas mixture. Both hypoxic gases induced significant ventilatory responses, and mean peak minute ventilation before the isocapnic normoxic switch was higher in 6% O2 (P < 0.001). The fast time constant of the two-exponential equation representing the best fit for ventilatory decay was unaffected by the magnitude of the hypoxic stimulus. However, the slow time constant, which is considered to represent VSTP, was markedly prolonged in 6% compared with 10% O2 [106.7 +/- 11.3 vs. 38. 2 +/- 6.1 (SD) s, respectively; P < 0.0001]. This result indicates that VSTP is stimulus dependent. We conclude that the magnitude of hypoxia preceding a normoxic transient modifies VSTP characteristics. We speculate that the interdependence function of ventilatory stimulus and short-term potentiation is crucial for preservation of system stability during transitions from high to low ventilatory drives.

Longitudinal assessment of hypercapnic ventilatory drive after tracheotomy in a patient with the Prader-Willi syndrome.

The clinical course and changes in hypercapnic ventilatory drive over time were serially assessed before and after tracheostomy placement in a 14 year old, morbidly obese female patient with Prader-Willi syndrome, severe obstructive sleep apnoea, and obesity-hypoventilation syndrome. A tracheostomy became necessary after supplemental oxygen and continuous positive airway pressure (CPAP) had failed to improve the severity of nocturnal hypoventilation. Continued improvement in the slope to rebreathing hyperoxic hypercapnia occurred from 2-10 weeks after tracheotomy in conjunction with night-time bilevel pressure ventilation, and remained unchanged thereafter. In contrast, increases in mean resting minute ventilation at an end-tidal carbon dioxide tension (PET,CO2) of 8 kPa (60 mmHg) were documented even after 30 weeks. This case study illustrates the time-frame of dynamic ventilatory changes occurring after removal of upper airway resistance and normalization of nocturnal alveolar ventilation.

Foreign body aspiration: experience at the University Pediatric Hospital.

Fifty eight patients were admitted to the University Pediatric Hospital with the diagnosis of foreign body aspiration from August 1986 to January 1991. Of this 58 admissions, 40 records were analyzed for incidence, clinical and radiological manifestations, morbidity and nature of the foreign material in an effort to compare our findings with those of other centers, including another previous study in our institution. Our data reveals that the event of aspiration of a foreign body was most common between 1 to 2 years of age, this comprises 18 (45%) of the cases; male to female ratio was 1:3; 17 (42.5%) cases were diagnosed during the first 24 hours of the event and another 42.5% were diagnosed after 48 hours. Coughing and a choking episodes were the most common signs of presentation with hyperaeration of the lung as the main radiological finding. The left main stem bronchus as the lodgement site and the peanut as the foreign object were the most common findings. The mortality ratio was 7.5%. It is important to make parents and health providers aware of patients at risk and knowledge of basic life support measures.