POST-MENOPAUSAL VERTEBRAL OSTEOPOROSIS: CAN DUAL ENERGY X-RAY ABSORPTIOMETRY FOREARM BONE DENSITY SUBSTITUTE FOR AXIAL MEASUREMENTS?

This study compared measurements of BMD using dual energy X-rayabsorptiometry (DXA) at three sites in the nondominant forearm(ultradistal, distal one-third and a mid-region between thesetwo), the lumbar spine (L1–L4) and the proximal femur(femoral neck, trochanter and Ward's triangle) for the evaluationof vertebral osteoporosis. Studies were performed on 100 normalwomen aged 29–69 yr (average 52 yr) and 63 osteoporoticwomen age 48–75 yr (average 66 yr) using the Hologic QDR–1000. Precision values of <1% were obtained in both normal andosteoporotic women at both forearm and axial sites. Z=scoresfor the osteoporotics [Z = (mean BMD normal — mean abnormal)/s.D.]were — 2.02 lumbar spine, –1.96 femoral neck, –1.79ultradistal forearm, –1.73 mid region and –1.66distal one-third forearm. Receiver operating characteristiccurves showed that the lumbar spine and femoral neck equallydiscriminated between normals and osteoporotics with a 95% areaunder each curve, significantly greater values than those forthe forearm which were 87% ultradistal, 89% mid forearm and86% distal one-third forearm. Fracture thresholds, defined asthe 90th centile of BMD for osteoporotic patients, were 1 s.D.below the normal mean for lumbar spine and femoral neck butequal to the mean for ultradistal, 0.6 S.D. below mean for midregion and 0.3 s.D. below mean for distal one-third region. We conclude that for the discrimination of normals and osteoporoticwomen the three forearm sites are comparable. However, bothlumbar spine and proximal femur BMD are superior to all forearmsites. KEY WORDS: Spine, Vertebra, Femur, Bone mass, Fracture     

Splenic regrowth in sickle cell anaemia following hypertransfusion

We describe five adult patients with sickle cell anaemia (SS) who developed clinical, radiological and histological evidence of splenic regrowth while receiving regular blood transfusions. Five patients, all homozygous SS, range 23–34 years, were commenced on hypertransfusion therapy. Three patients were transfused because of severe recurrent vaso-occlusive crises, one for chronic sickle lung and one in an attempt to prevent deterioration of renal function. The mean duration of hypertransfusion prior to documentation of splenic regrowth was 52 months (range 12–97 months). Two patients developed significant hypersplenism. One patient had clinically-apparent splenomegaly and four patients had splenomegaly documented on ultrasound. Splenic regrowth in hypertransfused adults with sickle cell anaemia is not infrequent and may have important clinical implications.     

Annular Array Technology: Application to Cardiac Imaging

Annular array imaging combines desirable features of both phased-array and mechanical transducer technology. Its major advantage is dual-plane electronic focusing, which contributes to deeper penetration, improved lateral resolution, and a thinner tomographic slice. All of these features help to improve image quality in the majority of patients. Areas of improvement observed with annular array imaging in the clinical setting include increased depth of field, better endocardia1 definiton, greater detail of valvular structures, more accurate recording of intracardiac masses, and generally improved signal-to-noise ratio. These aspects of improved image quality make annular array technology an important advance in ultrasonic cardiac imaging.     

Challenge of percutaneous nephrolithotomy in patients with spinal neuropathy

OBJECTIVE:To assess the technical difficulties, associated complications and stone clearance rates in patients with spinal neuropathy undergoing percutaneous nephrolithotomy. METHODS: Twenty-nine patients with spinal neuropathy underwent percutaneous nephrolithotomy in the two centers studied between October 1995 and January 2002. They were nine patients with traumatic spinal cord injury, 10 patients with spina bifida and 10 with other heterogeneous causes for their spinal neuropathy. The group included 12 men and 17 women, with an average age of 44 years (14-80). Patients' medical records were reviewed retrospectively for data relating to their renal lithiasis. RESULTS: A total of 39 percutaneous nephrolithotomy procedures were undertaken on 32 kidneys. Thirteen procedures were for staghorn calculi. Preoperatively, eight kidneys required nephrostomy and 5 J stent decompression. The average American Society of Anesthesiologists (ASA) score was 3, and one patient had percutaneous nephrolithotomy performed under local anaesthetic as the risk of general anaesthetic was felt to be too high. The associated morbidity and mortality in this group is significant. There were two postoperative deaths. Major complications were associated with three procedures, and consisted of seizures, aspiration pneumonia and pressure necrosis. Nine patients experienced minor complications including fever, hypotension and nephrostomy site leakage. Nine patients required intensive therapy unit care postoperatively and the average hospital stay for the group was 13.32 days. Only 18 (62%) patients were rendered stone-free from their initial percutaneous nephrolithotomy. Seven patients required a further procedure for stone clearance: four underwent extracorporeal shock-wave lithotripsy, two ureteroscopy and one nephrectomy. CONCLUSIONS: Patients with spinal neuropathy and renal lithiasis pose a significant operative challenge. Technical difficulties and potential complications should be considered carefully before undertaking percutaneous nephrolithotomy in these patients.     

Reproducible Induction of "Atypical" Torsades de Pointes by Programmed Electrical Stimulation:

Sotalol-Induced Polymorphic VT. We present a patient with sotalol-induced polymorphic ventricular tachycardia that was seen only with programmed ventricular stimulation. Electrophysiologic studies performed prior to initiation of sotalol therapy revealed inducible monomorphic ventricular tachycardia. Possible underlying electrophysiologic mechanisms are discussed.     

Testing airway responsiveness using inhaled methacholine or histamine

Abstract Airway responsiveness assessed using histamine and methacholine is safe, reproducible and relatively easily undertaken in adults and children. Results are similar for methacholine and histamine although methacholine is better tolerated. Responsiveness is increased in children and the elderly, and in women compared to men, possibly due to body size effects. Baseline lung function confounds the interpretation of airway responsiveness and may explain the effect of smoking in most studies. Results are most usefully expressed as the provocative dose producing a 20% fall in FEV₁ (PD₂₀FEV₁) or the dose-response slope (DRS). When technical factors are controlled the reproducibility of the test is from one to two doubling doses. Measurements of airway responsiveness have been widely used in clinical and research practice. However, assessing their value in diagnosing asthma is limited by the lack of a gold standard for the definition of asthma. Using a cut-off value of 8 mg/mL or 8 μmol for PD₂₀, the tests will discriminate asthmatic from non-asthmatic subjects (based on questionnaire definitions of asthma) with a sensitivity of around 60% and a specificity of around 90%. These properties of the test result in positive and negative predictive values of 86% and 69% when the prevalence of asthma is high (50%– as in the clinical setting) and 40% and 95% when the prevalence of asthma is low (10%, as in general population studies). In the usual clinical setting, assessing the significance of atypical or non-specific symptoms, the tests are of intermediate value in predicting the presence of asthma and less useful in excluding asthma. The additional benefit of testing airway responsiveness to measuring peak flows or to a trial of therapy has yet to be fully assessed. Testing of airway responsiveness may be of value in assessing occupational asthma, asthma severity and the effects of potential sensitizers or treatments. In research, tests of airway responsiveness are more useful for excluding cases of asthma. In population studies, they serve as an objective marker of abnormal airway function which may be genetically determined and, like allergy, are strongly associated with asthma. The predictive value of airway hyperresponsiveness for the development of airway disease is yet to be clearly established. In epidemiology the benefits of measuring airway responses must be weighed against the added inconvenience and cost that is incurred.