Biomedical subjects
Publications and source records attributed to J Massie.
Apparently minor chest trauma may result in localized pulmonary contusion. Complications of the contusion, particularly infection, may be delayed. The association between the infection and initial injury may not be appreciated due to the time frame between the injury and clinical presentation. We report two cases of low-moderate impact pulmonary trauma resulting in focal pulmonary contusion, complicated by infection.
AIMS: To investigate the immunoreactive trypsinogen (IRT) values above the usual 99th centile laboratory cut-off and determine the value of offering further testing to those infants with a markedly elevated IRT but no cystic fibrosis transmembrane regulator (CFTR) gene mutation identified by the screening programme. METHODS: All babies born in Victoria, Australia, between 1991 and 2003, were screened by IRT followed by CF gene mutation analysis. RESULTS: Of the 806,520 babies born, 9268 with the highest IRT levels had CFTR mutation analysis. There were 123 DeltaF508 homozygotes and 703 heterozygotes (86 with CF, 617 carriers). A total of 8442 babies had no CFTR gene mutation, of whom 18 (0.21%) had CF. The total number of CF babies with IRT greater than the laboratory cut-off was 227 (2.4%). The IRT results of the CF patients were distributed normally, with the majority above the laboratory cut-off of newborn IRT results. There was no evidence of an excess of babies with CF in the very highest levels of IRT above the 99th centile. CONCLUSIONS: Only a small proportion of babies with a neonatal IRT >99th centile have CF. Additional CF testing for infants with an elevated IRT but no CFTR gene mutation has an extremely low yield, no matter how high the IRT result.
BACKGROUND: Whooping cough is a highly contagious disease. Infants are the population at highest risk of severe disease and death. Erythromycin for 14 days is recommended for treatment and contact prophylaxis but this regime is considered inconvenient and prolonged. The value of contact prophylaxis is uncertain. OBJECTIVES: To study the benefits and risks of antibiotic treatment of and contact prophylaxis against whooping cough. SEARCH STRATEGY: The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2004); MEDLINE (January 1966 to February 2004); EMBASE (January 1974 to August 2003); conference abstracts and reference lists of articles were searched. Study investigators and pharmaceutical companies were approached for additional information (published or unpublished studies). There were no constraints based on language or publication status. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials of antibiotics for treatment of and contact prophylaxis against whooping cough were included in the systematic review. DATA COLLECTION AND ANALYSIS: At least three reviewers independently extracted data and assessed the quality of each trial. MAIN RESULTS: Twelve trials with 1,720 participants met the inclusion criteria. Ten trials investigated treatment regimens and two investigated prophylaxis regimens. The quality of the trials was variable. Results showed that short-term antibiotics (azithromycin for three days, clarithromycin for seven days, or erythromycin estolate for seven days) were equally effective with long-term antibiotic treatment (erythromycin estolate or erythromycin for 14 days) in the microbiological eradication of Bordetella pertussis (B. pertussis) from the nasopharynx. The relative risk (RR) was 1.02 (95% confidence interval (CI) 0.98 to 1.05). Side effects were fewer with short-term treatment (RR 0.66; 95% CI 0.52 to 0.83). There were no differences in clinical improvement or microbiological relapse between short and long-term treatment regimens. Contact prophylaxis (of contacts older than six months of age) with antibiotics did not significantly improve clinical symptoms or the number of cases that developed culture positive B. pertussis. AUTHORS' CONCLUSIONS: Antibiotics are effective in eliminating B. pertussis from patients with the disease, rendering them non-infectious, but do not alter the subsequent clinical course of the illness. Effective regimens include: three days of azithromycin, seven days of clarithromycin, seven or 14 days of erythromycin estolate, and 14 days of erythromycin ethylsuccinate. Considering microbiological clearance and side effects, three days of azithromycin or seven days of clarithromycin are the best regimens. Seven days of trimethoprim/sulfamethoxazole also appeared to be effective for the eradication of B. pertussis from the nasopharynx and may serve as an alternative antibiotic treatment for patients who cannot tolerate a macrolide. There is insufficient evidence to determine the benefit of prophylactic treatment of pertussis contacts.
AIMS: To evaluate a systematic approach to the development and implementation of evidence based asthma management guidelines. METHODS: Comparative study of children (2-18 years) with acute asthma; a control cohort (cohort 1) was recruited before implementation of the guidelines and two cohorts were recruited after implementation (cohorts 2 and 3). RESULTS: There was no difference in the proportion of patients who reattended in the six months following initial presentation for cohort 1 (21.5%), cohort 2 (27.8%), or cohort 3 (25.4%) and no difference in readmission rates (11.4%, 11.3%, 11.0% respectively). There was no difference in measures of asthma morbidity between the cohorts at 3 and 6 months across three domains: interval symptoms, exercise limitation, and bronchodilator use. Of those who did not have a management plan before presentation, one was provided to 46.9% of cohort 1, 74.8% of cohort 2, and 81.1% of cohort 3. There was no difference comparing cohort 2 or cohort 3 with cohort 1 regarding quality of life for either the subjects or their parents. CONCLUSIONS: Implementation of our evidence based guidelines was associated with the improved provision of asthma management plans, but there was no effect on reattendance or readmission to hospital, asthma morbidity, or quality of life. Future efforts to improve asthma management should target specific components of asthma care.
Newborn screening (NBS) for cystic fibrosis (CF) has been carried out in Victoria, Australia since 1989. The primary screen is immunoreactive trypsinogen (IRT) followed by DeltaF508 mutation analysis. As part of this process, carrier babies are detected and their parents are routinely offered carrier testing as part of their follow up. The DeltaF508 parent is identified and the other parent has an extended mutation analysis performed in case they are also a carrier. One of the mutations in the extended analysis is R117H which is associated with a broad phenotypic range, from CF with suppurative lung disease, to no clinical disease. We present four healthy DeltaF508 carrier babies identified by our NBS service with both parents identified as carriers, one DeltaF508 and the other R117H. Owing to the variable phenotype associated with R117H we have developed an approach to this difficult genetic counselling situation. Centres offering or considering NBS for CF will need an approach to this problem.
Airway masses are uncommon in children. The majority of bronchial tumors are granulomata secondary to an inhaled foreign body. However, other rare diseases like primary bronchopulmonary tumors should always be considered in the evaluation of a bronchial granuloma in children. The differential diagnosis of bronchial granuloma is presented. We report a 7-year-old girl with a 3-year history of recurrent cough and fevers who was found to have a bronchial granuloma in the left upper lobe bronchus. The diagnosis of foreign body-related granuloma was eventually made after combined and repeated rigid and flexible bronchoscopy. This case highlights the need to search aggressively for a foreign body in the presence of an airway granuloma in children, even in the absence of a history of aspiration.
Sweat testing remains the "gold standard" for the diagnosis of cystic fibrosis (CF) and is a critical component of newborn screening programs. We retrospectively reviewed sweat test results reported to a neonatal screening program for CF with respect to completeness of reported results and the values recorded for sweat chloride (Cl(-)) and sodium (Na(+)) concentrations and the Cl(-):Na(+) ratio in screened infants. Thirty-nine of 85 DeltaF508 homozygous (DeltaF508/DeltaF508) and 270 of 274 DeltaF508 heterozygous (DeltaF508/-) infants had sweat tests reported to the screening program. Of those, 30 and 213 sweat test reports, respectively, were complete, i.e., sweat weight, sweat chloride, and sodium were reported. Three centers accounted for 37 of 68 (54%) incomplete results, and 4 centers performed 4 or less post-screening sweat tests in the study period. There were 6 DeltaF508 heterozygous infants with sweat Cl(-) concentrations of 40-60 mmol/L and 4 had CF confirmed by additional genotyping (n = 2) or clinical and repeat sweat Cl results (n = 2). Forty-one percent of DeltaF508/-infants with sweat Cl(-) <40 mmol/L had Cl:Na >1. We conclude that the reporting of incomplete sweat tests is common following newborn screening for CF. Infants with sweat Cl(-) levels of 40-60 mmol/L require further investigation and review, but they almost certainly have CF. The Cl(-):Na(+) ratio does not appear useful in establishing a diagnosis of CF in infants.
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BACKGROUND: Misdiagnosis and over-interpretation of non-specific respiratory complaints is common in children. Once a diagnosis of asthma has been made, there is a confusing range of medications and delivery systems available. OBJECTIVE: To review the diagnosis of asthma in children, to understand the correct medication for the disease severity and choose the best delivery system. DISCUSSION: Having established the diagnosis, regular assessment of the disease severity and level of medication is required. Keeping the medication regimen simple, using the appropriate delivery system and using the lowest dose of medication to control symptoms are the keys to successful management of asthma in childhood.
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The pathophysiology of sciatica is not completely understood, although our understanding of its causes is increasing. Mechanical alterations combined with inflammatory changes lead to pain. Compression alters nerve root conduction and compromises the nutritional support of spinal nerve roots (through intrinsic and extrinsic vascularity and cerebral spinal fluid percolation). Mechanical forces can lead to intraneural damage and functional changes in nerve roots. Chemical and metabolic effects can create an inflammatory response. Varying causes of inflammation coupled with varying degrees of compression can occur anywhere along the cauda equina or spinal nerve root, including the dorsal root ganglia, and contribute to the pain response and neurologic deficits associated with sciatica.
This study examines effects of acute stretch on electrophysiologic properties of rabbit tibial nerve. Compound motor action potentials (CMAP) were measured in 30 rabbits, during and after two hours of acute, graded strain. The rabbits were assigned to one of three groups defined by the degree of stretch (0%, 8%, or 15%) beyond original resting length. These groups were subdivided according to ankle position during nerve strain (ankle dorsiflexion or ankle plantar flexion). Two hours of 8% strain did not significantly decrease CMAP amplitude. Fifteen percent strain with the ankle in dorsiflexion produced a significant and profound drop (99%) in CMAP amplitude. These findings are clinically relevant to nerve stretch injuries and to surgical procedures that induce acute nerve strain.
Mechanical stretching is known to cause morphologic and functional changes in peripheral nerve. The points at which these changes occur, however, are not clearly defined and reported data are conflicting. The studies presented in this paper provide a basic understanding of the biomechanical properties, stretch-injury patterns, and changes of conduction properties of peripheral nerves due to stretching. Our studies showed that peripheral nerves exhibited non-linear stress-strain characteristics when placed under tension. Initially, under tension, the nerve had a low modulus that increased gradually with increasing strain until reaching a maximal value. When the nerve failed under tension, the perineurium inside the nerve ruptured, but the exterior of the nerve remained intact. Our results also show that a peripheral nerve in situ was under significant strain, but minimal in situ stress (less than 0.05 MPa). The in situ strain might vary with limb position, but did not appear to exceed the limit beyond which substantial tension or stress would be developed in the nerve. The time-dependent viscoelastic behavior of peripheral nerves were also characterized. The maintenance of small in situ stresses suggests that sustained increases in tension could be adversely affecting the electrophysiologic properties of the nerve. Indeed, marked alteration of conduction properties resulted from even a small stretch of 6 percent beyond the in situ length of the nerve, or stress less than 10 percent of the ultimate strength of the nerve.
Instrumentation of the lumbosacral spine increasingly involves screw fixation to the sacrum. Recommended locations and techniques for screw placement vary, particularly when bicortical purchase of the sacrum is performed. The purpose of this study was to describe the critical anatomy and potential injuries to neurovascular and visceral structures anterior to the sacrum. Lack of awareness can lead to life-threatening complications. The study included 22 fresh human cadavers with no prior spinal surgery. Specimens were placed in a prone position, and the lumbosacral spine was exposed. Two 6.5-mm screws were inserted using one of two techniques, respectively: Starting just inferior to the S1 facet one screw was angled 25 degrees caudally and 30 degrees laterally; in the second technique, lateral inclination was increased to 45 degrees. In addition, all specimens had screws placed in the S2 pedicles. An anterior dissection was performed to allow evaluation of the neurovascular and visceral structures at risk for injury by, or adjacent to, the screw tips. All significant neurovascular structures in the area of concern were constant in position. The internal iliac vein and the lumbosacral nerve trunk were most at risk for injury by the 30 and 45 degrees laterally directed screws. The sigmoid colon, though close to the S2 screw, was protected by its mesentery. Screws placed in the S1 pedicle were least likely to injure the neurovascular bundle. A lateral and a midline safe zone were identified.