JOURNAL CLUB

Commentaries By Michael G. Burke, MD

Gun storage practices: Whom do you ask?

Women living in homes where guns are stored may be unaware that these firearms are not stored safely, according to new research. Using a national, random, digit-dial telephone survey, investigators analyzed responses from 434 households with children younger than 18 years in which an adult (generally a man) either personally owned a gun or lived in a gun-owning household but did not personally own a gun (generally a woman). Whereas 21% of gun owners said that a household gun was stored loaded, only 7% of nonowners made a similar report. Likewise, 9% and 2%, respectively, indicated that a household gun was stored loaded and unlocked. These findings, investigators said, suggest that nongun owners in homes with guns, 87% of whom are women, may be unaware that guns in their homes are stored in a way that experts agree is unsafe (Azrael D et al: Pediatrics 2000;1063:e31).

Commentary: What is the moral of this story? When you ask for history with regard to storage of guns in the home, consider the source of the information. Target your anticipatory guidance to your audience. Encourage nonowners living in homes with guns to find out how those guns are stored. If the gun owner is in the office, tell him directly the advantages of locking and unloading his firearms.

Is PCR cost-effective for aseptic meningitis?

A new study supports investigators' hypothesis that clinical application of enteroviral polymerase chain reaction (ePCR) in the diagnosis of meningitis has potential cost savings in the form of shorter hospital stays and decreased antibiotic use. Use of the ePCR assay on cerebral spinal fluid (CSF) produces results within five hours, compared with a mean of 4.2 days required to detect viral growth by culture. The ePCR test has been shown to be significantly more sensitive than culture.

Investigators reviewed the records of 126 infants admitted to a hospital with fever, CSF pleocytosis, and a negative CSF Gram stain, most of whom were discharged with a diagnosis of aseptic meningitis. The total cost related to these patients was $381,145. Testing the patients with ePCR would have cost $11,340. A positive ePCR result would save 1.3 hospital days per patient by allowing discharge at 24 hours, resulting in a savings of $1,037 per patient. The break-even point—when the additional cost of the ePCR testing would be the same as the costs saved by the reduction in hospital stays—would occur when enteroviral meningitis had a prevalence of 5.9%. Thus, total cost savings of 10%, 20%, and 30% would be achieved at an enteroviral meningitis prevalence of 36.3%, 66.7%, and 97.1%, respectively. The authors note that limiting use of ePCR to the enterovirus season would enhance cost savings (Nigrovic LE et al: Arch Pediatr Adolesc Med 2000;154:817).

Commentary: The authors' model assumed that PCR diagnosis of enteroviral infection within 24 hours of admission would allow the physician to discharge the child to home at 24 hours. They compared this with continuing empiric antibiotics until bacterial cultures were checked at 48 hours. They took into account the varying value of the PCR tests as prevalence of disease changes. Fewer of your positives will be false positives during enteroviral season. An accompanying editorial draws a parallel between PCR and Guttenberg's invention of printing from moveable type. Like the printing press, PCR may cause an information explosion that changes the way we do medicine.

Contamination risk high for bagged urine

Canadian investigators compared the risks of contaminated culture results in urine specimens obtained by the "clean-voided" bag method compared with catheterization. The more than 7,500 urine cultures were obtained from children up to 2 years of age. Overall, 39.4% of the urine cultures were negative, 15.2% were positive, and 45.4% were contaminated. The risk of contaminated culture results differed markedly by the method of urine culture. Of catheter specimens, 9.1% were contaminated compared with 62.8% for bag specimens. Of the 3,440 contaminated urines, 132 (1.7%) resulted in one or more adverse clinical outcomes, such as unnecessary recall to the hospital for repeat urine culture (for which the result was negative or caused no change in management), delayed diagnosis and treatment of a true urinary tract infection, unnecessary treatment, unnecessarily prolonged treatment, or unnecessary radiologic investigation (Al-Orifi F et al: J Pediatr 2000;137:221).

Commentary: It's no surprise that bag specimens were more likely to be contaminated than catheter specimens. I was impressed at the 62% figure for contaminated bags, however. It certainly makes you think twice before applying the bag.

Breastfeeding tied to rickets resurgence

Puzzled by their perception of an increase in nutritional rickets, investigators in North Carolina reviewed the records of all patients from two pediatric endocrinology clinics who received a diagnosis of nutritional rickets during the past decade. All 30 patients were African-American. All were breastfed, for an average of 12.5 months, and none had received vitamin D supplementation. Sixteen of the 30 had visible skeletal abnormalities; 13 of 30 had failure to thrive. All 30 had classic radiologic changes of rickets. Children older than 1 year had a history of poor intake of fortified cow's milk or other dairy products. Seventeen of 30 patients presented in the last two years of this retrospective study.

Why has there been an increase in referrals for rickets? The authors propose several reasons:

• The increase in incidence of breastfeeding in African-American women (from 5% to 22% in North Carolina women on the Special Supplemental Nutrition Program for Women, Infants, and Children). This increase, combined with the greater tendency of dark-skinned mothers and babies to develop vitamin D deficiency compared with those who are light skinned, may have led to these findings.

• A decrease in the number of infants receiving vitamin D supplementation. A survey of 400 pediatricians in North Carolina revealed that 42% prescribe vitamin supplements for all breastfeeding infants, 42% for selected breastfeeding infants, and 16% for no breastfeeding infants. Of those who do prescribe supplements, 24% do not do so until the infant is 6 months or older.

Investigators also noted that dark-skinned individuals require more sunlight exposure than white individuals to produce the same amount of vitamin D and suggested that another possible cause of the recent increase in rickets referrals could be decreased exposure to sunlight (Kreiter SR et al: J Pediatr 2000;137:153).

Commentary: These babies may be victims of our success. In North Carolina, as in other states, the percentage of African-American mothers who breastfeed has increased. The 1998 AAP Nutrition Handbook recommends 400 IU/day vitamin D supplementation for deeply pigmented breastfed infants, particularly if they are exposed to minimum amounts of sunlight.

Also of note

Being a twin may protect against asthma. A record linkage study performed in Scotland indicates that twins are less likely to require hospitalization for asthma than singletons are. Investigators compared rates of hospital admission for respiratory disease among singletons and twins up to 10 years of age by cause and sex. The investigation related to all children born in Scotland between 1981 and 1984. Singletons were twice as likely as twins to be admitted with asthma. In contrast, twins were at significantly more risk than singletons for being admitted for acute bronchitis and bronchiolitis. Investigators hypothesized that being a twin protects against asthma in much the same way as being in a large family does (Strachan DP et al: BMJ 2000; 321:732).

VAERS data support safety of acellular pertussis vaccine. From 1995 to 1998 the number of reports, both serious and less serious, to the Vaccine Adverse Event Reporting System (VAERS) for pertussis-containing vaccines declined substantially. At the beginning of the period, whole-cell pertussis vaccine was used nearly exclusively for infant immunization. By the end of the period, use of acellular pertussis vaccine predominated. According to an analysis of VAERS data, the number of reported events categorized as nonfatal serious declined from 334 in 1995 to 93 in the first half of 1998. The annual number of less serious reports to VAERS for pertussis-containing vaccines showed a similar decrease during the period: from 1,652 in 1995 to 357 in the first half of 1998. These data represent temporal, but not necessarily causal, associations between vaccinations and adverse events. Data are subject to limitations of passive reporting but point to decreased reactions associated with pertussis vaccination (Braun MM et al: Pediatrics 2000;106[4]: e51).

DR. BURKE, Section Editor for Journal Club, is Chairman of the Department of Pediatrics at Saint Agnes Hospital, Baltimore. He is a Contributing Editor for Contemporary Pediatrics.

CLINICAL TIP

Pass the salt, please

Many of my patients complain about the "iron-like" taste of clarithromycin (Biaxin). I have found that eating potato chips, or any salty food, before taking clarithromycin neutralizes the flavor. Suggesting this strategy to patients improves compliance and ensures that they take the entire amount of prescribed medication.

Kourosh Parsapour, MDDetroit, MI

Do you have a Clinical Tip to share with colleagues? Let us know; we’ll pay $50 for each item accepted for publication. Tips sent by mail should be addressed to Molly Frederick, Clinical Tips Editor Contemporary Pediatrics, 5 Paragon Drive, Montvale, NJ 07645-1742. If you submit by e-mail (Molly.Frederick@medec.com), please include your mailing address.

 

Michael Burke. Journal Club. Contemporary Pediatrics 2000;12:140.