Using the script concordance test to assess clinical reasoning skills in undergraduate and postgraduate medicine.

The script concordance test is a relatively new format of written assessment that is used to assess higher-order clinical reasoning and data interpretation skills in medicine. Candidates are presented with a clinical scenario, followed by the reveal of a new piece of information. The candidates are then asked to assess whether this additional information increases or decreases the probability or likelihood of a particular diagnostic, investigative, or management decision. To score these questions, the candidate's decision in each question is compared with that of a reference panel of expert clinicians. This review focuses on the development of quality script concordance questions, using expert panellists to score the items and set the passing score standard, and the challenges in the practical implementation (including pitfalls to avoid) of the written assessment.

Effect of different time phases of radionuclide hepatobiliary scintigraphy on the differential diagnosis of congenital biliary atresia.

To investigate the value and essentiality of 6- and 24-h delay hepatobiliary scintigraphy in the differential diagnosis of biliary atresia (BA), we retrospectively analyzed 197 infants (121 boys/76 girls; age range, 3-205 days; average age, 63.9 days) admitted to Jiangxi Children's Hospital for persistent jaundice (> 2 weeks), hepatosplenomegaly, and abnormal liver function. After receiving anti-inflammatory treatment and cholagogic pre-treatment for 7-10 days without a clear diagnosis, the children underwent 99mTc-labeled diethylacetanilide-iminodiacetic acid hepatobiliary scintigraphy. BA and infant hepatitis syndrome were diagnosed in 107 and 90 infants, respectively after laparoscopic cholangiography, surgical pathology, or 6-month clinical follow-up. The diagnostic efficiencies of hepatobiliary scintigraphy for BA were evaluated within 50 min and at 6 and 24 h. The areas under the receiver operating characteristic curves within 50 min, at 6 and 24 h were 0.696, 0.829 , and 0.779 , suggesting poor diagnostic value within 50 min, but improvement at 6 and 24 h. The compliance rate of 6- and 24-h imaging for BA diagnosis was 89.34% (176/197; paired chi-square test Kappa value, 0.77; P > 0.05), signifying high consistency. The diagnostic efficiency values of 6-/24-h imaging for BA diagnosis were sensitivity (90.65/89.72%), specificity (74.44/78.89%), accuracy (83.25/84.77%), positive and negative predictive values (80.83/83.48% and 87.01/86.59%), with no significant difference (P > 0.05). To provide optimal treatment in early BA, the- 6-h hepatobiliary scintigraphy had practical value, especially when combined with tomographic or dynamic imaging; 24-h delay imaging was deemed unnecessary because it was not significantly superior.

Brugada syndrome.

As a clinical entity the Brugada syndrome has existed since 1992 and has been associated with a high risk of sudden cardiac death predominately in younger males. Patients can present with symptoms (ie syncope, palpitations, aborted sudden cardiac death) and asymptomatically. Its three characteristic electrocardiographic patterns can occur both spontaneously or after provocation with sodium channel-blocking agents. Risk stratification and the need for treatment depend on the patient's symptoms, electrocardiography, family history, and electrophysiological inducibility to discern if treatment by implantable cardioverter defibrillator, the only effective treatment to date, is appropriate. This review focuses on Brugada syndrome and various aspects of the disease including proposed mechanisms, epidemiology, clinical presentations, genetics, diagnosis, risk stratification, and treatment options.

Trigger thumbs in children: results of surgical release.

OBJECTIVE. To evaluate results from surgical release of trigger thumbs in children in a regional hospital cluster in Hong Kong. DESIGN. Descriptive case series. SETTING. A regional hospital cluster, Hong Kong. PATIENTS. Data from 1993 to 2009 on 180 children with 209 trigger thumbs were collected. Analyses into gender, predominance of thumb, age of onset, associated abnormalities and family history, symptoms and signs, surgical outcomes, and postoperative complications were carried out retrospectively. RESULTS. There were 92 girls and 88 boys having trigger thumbs (1.05:1). In all, 29 (16%) of the children presented with bilateral trigger thumbs, while the right thumb was singly involved in 81 (45%) and the left thumb in 70 (39%) of the children. The mean age of onset was 19 months; only 20% were diagnosed before the age of 1 year. Only nine (5%) of the children were associated with congenital diseases and none had a positive family history of trigger thumb. Flexion deformity was the major presenting feature, other than triggering or pain. A nodule and flexion deformity were very commonly observed during physical examination. More than 95% of the operated thumbs with transverse incision acquired a good range of movement with a scarcely apparent scar. A residual flexion deformity was evident in only 4%, mostly in children who underwent surgical release under the age of 1 year. CONCLUSION. Surgical release is recommended for children with trigger thumbs aged more than 1 year, which attains satisfactory results with minimal complications.

A rare cutaneous fungal infection complicating bacterial necrotising fasciitis.

We report a case of bacterial necrotising fasciitis complicated by the rare fungus Absidia corymbifera. Although this fungal infection is rare, the prognosis is poor and it therefore requires attention. Only 30 cases have been reported since 1874, and we are the first group to report this clinical scenario in our locality. Using a comprehensive journal review, we discuss the expected clinical course and optimal management.

Clinical experience of open carpal tunnel release and Camitz operation in elderly Chinese patients.

OBJECTIVE: To report preliminary experience on the Camitz operation for elderly Chinese patients in a Hong Kong public hospital. DESIGN: Retrospective study. SETTING: Tertiary referral hospital with hand surgery service in Hong Kong. PATIENTS: Between January 2000 and January 2004, patients with carpal tunnel syndrome having the Camitz operation were recruited. They were assessed using the measurements of pinch and grip power, sensation, the Kapandji score, and functional grading as well as complications encountered during the subsequent follow-up. INTERVENTION: The Camitz operation. RESULTS: A total of 21 patients (8 male and 13 female; mean age, 70 years) were recruited. The mean duration of follow-up was 15 months. There was significant improvement in pinch power, grip power, and hand functions, as well as a positive correlation between the functional score and the Kapandji score. No major complication was recorded. One patient with pre-existing osteoarthritis of the ring finger developed contracture of the proximal interphalangeal joint. CONCLUSION: The Camitz operation is a simple, effective, and safe means of improving hand function in elderly Chinese patients with long-standing carpal tunnel syndrome and thenar muscle atrophy. Newly acquired strength in antepulsion of thumb resulted in improved pinch, grip, and hand function in this patient group.

Prevention of ventricular fibrillation by pacing in a man with Brugada syndrome.

The unique ECG appearance of Brugada syndrome is caused by failure of the dome of the action potential to develop. It occurs when the outward currents (mainly Ito) overwhelm the inward currents (mainly Ica) at the end of phase 1 of the action potential. Because Ito becomes less prominent at a faster rate, increased heart rate is associated with decreased ST segment elevation on ECG and probably decreased incidence of ventricular arrhythmia. We present the first report on prevention of ventricular fibrillation in a man with Brugada syndrome by overdrive pacing from his dual chamber implantable cardioverter defibrillator.

Reversal of left ventricular remodeling by synchronous biventricular pacing in heart failure.

Synchronous biventricular pacing is a new nonpharmacological supplemental treatment of advanced heart failure associated with electromechanical conduction delay. However, the role of pacing on left ventricular remodeling is unknown. Eleven patients with New York Heart Association Class III to IV heart failure, a left ventricular ejection fraction < 35%, and a QRS duration > or = 140 ms received a biventricular dual chamber pacemaker. Serial echocardiography, 6-minute hall walk, and Minnesota Living with Heart Failure quality-of-life (QOL) questionnaire were performed before and after up to 3 months of pacing. At 3 months there was a significant increase in fractional shortening (P < 0.001), ejection fraction (P < 0.001), and cardiac output (P < 0.05). The left ventricular end-diastolic volume (245 +/- 70 vs 185 +/- 37 mL, P < 0.05), end-systolic volume (209 +/- 69 vs 140 +/- 44 mL P < 0.05), and mitral regurgitation were reduced (P < 0.05), and diastolic filling time was lengthened (P < 0.05). There were also improvements in heart failure symptoms, an increase in 6-minute walk distance, and a decrease in QOL scores. Synchronous biventricular pacing for 3 months was associated with hemodynamic improvements, reversal of left ventricular remodeling, and increase in left ventricular systolic function, and a decrease in secondary mitral regurgitation.

Lack of benefit of very short basic drive train cycle length or repetition of extrastimulus coupling intervals for induction of ventricular tachycardia.

INTRODUCTION: There are considerable variations of uncertain importance in basic drive train cycle lengths and degree of repetition of extrastimuli used in programmed ventricular stimulation protocols in different laboratories. We compare prospectively three different stimulation protocols to examine the influence of a short basic drive train cycle length and repetition of extrastimuli on induction of ventricular tachycardia. METHODS AND RESULTS: Thirty consecutive patients who had documented ventricular tachycardia or fibrillation based on underlying coronary artery disease underwent programmed ventricular stimulation with each of the three study protocols. Protocol A used a basic drive train cycle length of 400 msec with each extrastimulus coupling interval delivered only once. Protocol B used the same basic drive train cycle length, but with each extrastimulus coupling interval repeated three times before decrementing. Protocol C used 300 msec as the cycle length of basic drive trains without repetition of extrastimuli. Sixty-three percent, 67%, and 63% of the study patients had ventricular tachycardia inducible with protocols A, B, and C, respectively (P = NS). Ventricular fibrillation was induced in 23% of the 30 patients in all three protocols. There were no significant differences in the mean cycle lengths of induced ventricular tachycardia, the number of extrastimuli used, and the coupling interval of the last extrastimulus inducing ventricular tachycardia among the three protocols. CONCLUSION: This study showed no clinical benefit for repetition of extrastimuli that have failed to induce a ventricular tachyarrhythmia during programmed ventricular stimulation. A short basic cycle length of 300 msec was not superior to 400 msec for induction of ventricular tachyarrhythmias. We recommend the use of basic cycle length 400 msec with delivery of each extrastimulus interval only once as the initial protocol for programmed ventricular stimulation.

Myocardial and skeletal muscle injuries following adenine arabinoside therapy.

A healthy young male with chronic persistent hepatitis associated with positive HBsAg and HBeAg and without any predisposing factors for coronary artery disease was treated with a course of prednisolone and adenine arabinoside. At the end of therapy, he developed myocardial and skeletal muscle injuries. The temporal relationship between the administration of the drug and the monophasic nature of the myotoxic injuries strongly suggests that adenine arabinoside induced the clinical manifestations in the patient.

Complications of chronic glue (toluene) abuse in adolescents.

Recently there has been an alarming increase in the number of schoolchildren sniffing glue (toluene). The medical complications seen in 18 boys, aged 14 to 18 years, include physical and mental dependence, pulmonary hypertension with cor pulmonale, restrictive lung defect, encephalopathy, peripheral neuropathy and high frequency, continuous discharges ( neuromyotonia ) on electromyogram. Glue sniffing took place in small groups and abusers sniffed directly from cans containing glue. Lower socio-economic status, overcrowding, lack of attention by working parents, school failure and easy availability of the glue were commonly cited associated factors.

Pharmacokinetics and metabolism of naproxen in children.

The metabolism and pharmacokinetics of orally administered naproxen were studied in 10 children aged 6-13 years. 3 patients received the drug for antipyresis and 7 for postoperative pain. The mean elimination rate constant was greater in the febrile children than the postoperative patients, 0.064 h-1 vs. 0.051 h-1. 71% of total drug recovered in urine was naproxen, and 29% was excreted as the desmethyl metabolite. 60 and 63% of naproxen and desmethyl naproxen, respectively, were excreted as conjugates. Area under the curve and fraction of dose recovered in the urine were reduced in the postoperative patients, suggesting reduced gastrointestinal absorption of the drug compared to the febrile patients.

Effect of probenecid on the natriuresis and renin release induced by bumetanide in man.

In a randomized crossover trial in six normal male subjects, the effect of pretreatment with probenecid on natriuresis and renin release in response to bumetanide was studied. The subjects received 120 mEq sodium and 80 mEq potassium per day. A single dose of 2 mg bumetanide was administered on the fourth morning after pretreatment with either placebo or probenecid. Creatinine and uric acid were measured in serum and urine, plasma renin activity was determined by radioimmunoassay of angiotensin I, and plasma and urine concentrations of bumetanide were measured by a highly sensitive radioimmunoassay method. Probenecid reduced both natriuresis and hyperreninemia induced by bumetanide. This effect is postulated to be due not to a direct action on sodium excretion but is probably secondary to inhibition of renal tubular secretion of bumetanide. Consequently, these findings appear to support the concept that the quantity of bumetanide delivered to the tubular lumen is an important determinant of its diuretic effect.

Haemodynamic profile of acebutolol in acute myocardial infarction.

This paper evaluates the haemodynamics of intravenous Acebutolol (SECTRAL) (0.5 mgm/Kgm) in the acute phase of myocardial infarction uncomplicated by hypertension, cardiac failure or conduction abnormalities. Nineteen observations were made on 15 consecutive patients. Haemodynamic parameters were recorded just before, and at 15 and 30 min after injections, using Swan-Ganz Catheter-Thermister and Edslab Cardiac Output Computer (9520) in the Intensive Care Unit. All patients survived; none had extension of infarction. The Heart Rate dropped by 9 +/- 1% (+/- SEM) (from 90.2 +/- 4.0 to 81.6 +/- 3.1 per min, P less than 0.001) but systolic and mean Blood Pressures were not significantly altered. Pulmonary Capillary Pressure was elevated by 2.5 +/- 6% (from 11.6 +/- 0.8 to 14.4 +/- 0.9 mmHg P less than 0.001) but cardiac failure hardly ever developed clinically. The mean Pulmonary Arterial Pressure rose by 10 +/- 2% (P less than 0.005) while the Right Atrial mean increased from 6.0 +/- 1.0 to 8.3 +/- 1.3 mm Hg (P less than 0.005). Although the Cardiac Index was depressed by 11 +/- 2% (from 3.0 +/- 0.1 to 2.7 +/- 0.1 L/min/M2; P less than 0.001), the Stroke Index remained virtually unaffected. Myocardial oxygen consumption per min as reflected by Heart Rate x BP product declined by 12 +/- 2% (P less than 0.001), while the Stroke Work Index was lowered by 9 +/- 3% (P less than 0.005). The haemodynamic profile indicates that intravenous Acebutolol in uncomplicated infarcts is well tolerated, and that it could be employed with advantage to manipulate determinants of myocardial oxygen consumption through reduction of Heart Rate Pressure product and Stroke Work Index.

Pharmacokinetics, pharmacology of atenolol and effect of renal disease.

1. The pharmacokinetics of intravenous and oral atenolol (50 mg) in six healthy volunteers was studied. Plasma, saliva and urine were collected up to 24 h after each dose. 2. There was no significant difference in atenolol half-life when administered by the two routes. Bioavailability of the orally administered atenolol was 50%. 3. Atenolol levels in saliva required about 2 h to reach equilibrium with plasma drug levels. 4. A comparison between the pharmacokinetics and pharmacology of atenolol was made in twelve healthy subjects. 5. Dose-independent pharmacokinetics were observed. Reductions in resting heart rate and arterial blood pressure were proportional to either the logarithm of dose or area under the plasma concentration time curve or cumulative urinary atenolol excretion. 6. Plasma elimination half-life in five subjects with renal failure was prolonged.

Clinical evaluation of the EMIT procainamide and N-acetylprocainamide assay.

Procainamide and its major metabolite, N-acetylprocainamide, were measured by the homogeneous enzyme immunoassay technique (EMIT). The reagents for the EMIT assays were supplied as a separate matched set for each assay. There is no cross-reactivity by procainamide in the assay for N-acetylprocainamide or by N-acetylprocainamide in the assay for procainamide. Within-day precision determined by replicate analysis of samples in the therapeutic range gave a coefficient of variation of less than 5% for each assay. The day-to-day coefficient of variation was less than 6% for each assay. Quantitative results obtained by the enzyme immunoassay on serum samples from patients receiving procainamide were compared with the results obtained by a high pressure liquid chromatography procedure. For the procainamide assay the correlation coefficient (r) was 0.983; for the N-acetylprocainamide assay the correlation coefficient was 0.981. There was no false positives or false negatives. The immunoassay requires 50 microliters of serum and the enzyme activity is measured in a spectrophotometer. An individual determination requires only 1 min to perform; therefore, the procedure can be used for either emergency or routine analysis.

GLC determination of atenolol and beta-blocking agents in biological fluids.

A rapid, sensitive, and specific method of analysis for atenolol is described. Metoprolol is used as the internal standard. Atenolol and metoprolol are extracted into 1-butanol--benzene. Interfering components present in palsma and urine, but not discolored saliva, are removed during an acid wash and reextraction into ether. Drug and internal standard are converted to the pentafluoropropionate derivatives, which are quantitated by GLC with electron-capture detection and characterized by chemical-ionization mass spectrometry. The method should be applicable to measurement of other beta-adrenergic blocking agents with similar structures.