PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

BACKGROUND

Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment.

METHODS

All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals.

RESULTS

A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death.

CONCLUSION

Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions.

Hypothesised cutaneous sites of origin of stage III melanomas with unknown primary: A multicentre study

Based on molecular evidence that melanomas with unknown primary (MUPs) arise from the skin, we hypothesised that sites of MUPs are disproportionately on trunk and lower limbs, sites that are not readily visible to patients and clinicians. We tested this hypothesis by inferring the anatomic site of origin of MUPs from the corresponding known cutaneous sites of melanoma patients with known primary tumours (MKPs). We analysed data from three separate cohorts of patients from Brisbane, Australia (n = 236); Manchester, UK (n = 51) and Padova, Italy (n = 33), respectively, who first presented with stage III melanoma with lymph node metastases. We matched two MKP patients to each MUP patient based on lymph node dissection (LND) site, age and sex, and imputed cutaneous sites of origin of MUPs from their two matched MKPs for study countries, giving two possible sites for each MUP per centre. Overall, results showed that MUP patients were predominantly male, and trunk was the most likely origin, comprising around a third to a half of MUPs across the three cohorts. The remaining MUP inferred sites varied by country. In the Australian cohort, the legs accounted for a third of imputed sites of MUPs, while in the UK and Italian cohorts, the most frequent site was the arms followed by the legs. Our findings suggest the need for regular and thorough skin examination on trunk and limbs, especially in males, to improve early detection of cutaneous melanoma and reduce the risk of metastatic disease at the time of presentation.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Impact of pre-operative Metyrapone therapy on post-operative Steroid dependence in patients undergoing Adrenalectomy for Cushing’s Syndrome

Introduction

Prolonged elevated cortisol in Cushing’s Syndrome can lead to adrenal insufficiency post-adrenalectomy. Metyrapone is licensed to suppress endogenous cortisol production pre-operatively for symptom relief. The aim of this study was to investigate whether pre-treatment of patients with metyrapone led to reduced adrenal insufficiency, hence reduced steroid dependence post-op.

Methods

Cases were identified from UKRETS submissions between 2008–2020, with Electronic Patient Records used for data collection. Patients with adrenocortical carcinoma (ACC) and/or lost to follow-up were excluded. The remaining cases were divided into those treated with metyrapone pre-operatively and those not. Results were analysed via IBM SPSS Statistics software.

Results

Of 59 patients, those lost to follow up (n=6) and those with ACC (n=4) were excluded leaving 49 cases. Metyrapone patients (n=29) had a median of 3 symptoms of cortisol excess (0–9) compared to 2 symptoms (0–5) in non-metyrapone (n=20) (p=0.061). 82.8% (n=24) of metyrapone patients and 65% (n=13) of non-metyrapone patients were successfully weaned off steroids post-op, with the remaining patients still steroid dependent. Cox proportional hazards regression showed metyrapone did not impact steroid dependence (p=0.230). Metyrapone treatment increased the likelihood of adrenal recovery whereas increasing symptom burden reduced the likelihood (hazard ratio 0.271 and -0.143 respectively), however these findings were not significant (p=0.445 and p=0.117 respectively).

Conclusion

We found metyrapone had no significant impact on rate of adrenal failure. A larger series may more accurately determine whether metyrapone pre-operatively confers a higher likelihood of adrenal recovery and determine whether high symptom burden pre-operatively increases risk of steroid dependence post-operatively.

787 Evaluation of the role of anal tone and perianal sensation examination in the assessment of suspected cauda equina syndrome

Aims/Objectives/Background

Cauda equina syndrome (CES) can present with a varied constellation of clinical signs and symptoms, which together with the time sensitive nature of the condition and risk of catastrophic clinical outcome, presents a significant challenge to those assessing patients with this suspected diagnosis. Anal tone is commonly tested during initial assessment using a digital rectal examination (DRE). This study aims to evaluate the diagnostic value of anal tone and perianal sensation assessment in patients with suspected CES and report modern prevalence data on CES within a neurosciences centre.

Methods/Design

Consecutive patients with suspected CES presenting over a three-year period to the Emergency Department (ED) of a busy tertiary centre were included in the study. History and examination findings, documented in the ED notes, were assessed and these variables were correlated with the presence or absence of cauda equina compression on subsequent magnetic resonance imaging (MRI).

Results/Conclusions

Out of 1005 patients with suspected CES, 117 (11.6%) had MRI confirmed cauda equina compression (MRI +ve CES). 35% of MRI +ve patients and 31% of MRI -ve patients had reduced anal tone. Using univariate and multivariable logistic regression analyses, no associations were found between abnormal anal tone and MRI +ve CES for patients of all ages. The univariate logistic regression analysis identified altered perianal sensation to be significantly associated with MRI +ve CES in patients ≤ 42 years old. This association was no longer present when an adjusted multivariable logistic regression was performed.

The prevalence of MRI +ve CES was 11.6%. Our findings suggest that the clinical finding of reduced anal tone has no demonstrable diagnostic value for those with suspected CES, either in itself or in combination with other clinical findings. Further studies are needed to confirm the diagnostic efficacy of assessing perianal sensation in this context.

Evaluation of the role of anal tone and perianal sensation examination in the assessment of suspected cauda equina syndrome

PURPOSE

Cauda equina syndrome (CES) can present with a varied constellation of clinical signs and symptoms, which together with the time-sensitive nature of the condition and risk of catastrophic clinical outcome, presents a significant challenge to those assessing patients with this suspected diagnosis. Anal tone is commonly tested during initial assessment using a digital rectal examination (DRE). This study aims to evaluate the diagnostic value of anal tone and perianal sensation assessment in patients with suspected CES and report modern prevalence data on CES within a neurosciences centre.

MATERIALS AND METHODS

Consecutive patients with suspected CES presenting over three years to the Emergency Department (ED) of a busy tertiary centre were included in the study. History and examination findings, documented in the ED notes, were assessed and these variables were correlated with the presence or absence of cauda equina compression on subsequent magnetic resonance imaging (MRI).

RESULTS

Out of 1005 patients with suspected CES, 117 (11.6%) had MRI confirmed cauda equina compression (MRI + ve CES). 35% of MRI + ve patients and 31% of MRI -ve patients had reduced anal tone. Using univariate and multivariable logistic regression analyses, no associations were found between abnormal anal tone and MRI + ve CES for patients of all ages. The univariate logistic regression analysis identified altered perianal sensation to be significantly associated with MRI + ve CES in patients ≤42 years old. This association was no longer present when an adjusted multivariable logistic regression was performed.

CONCLUSION

The prevalence of MRI + ve CES was 11.6%. Our findings suggest that the clinical finding of reduced anal tone has no demonstrable diagnostic value for those with suspected CES, either in itself or in combination with other clinical findings. Further studies are needed to confirm the diagnostic efficacy of assessing perianal sensation in this context.

Adequacy of Mediastinal Lymph Node Sampling in Patients With Lung Cancer Undergoing Lung Resection

BACKGROUND

Intraoperative mediastinal lymph node sampling (MLNS) is a crucial component of lung cancer surgery. Whilst several sampling strategies have been clearly defined in guidelines from international organizations, reports of adherence to these guidelines are lacking. We aimed to assess our center's adherence to guidelines and determine whether adequacy of sampling is associated with survival.

MATERIALS AND METHODS

A single-center retrospective review of consecutive patients undergoing lung resection for primary lung cancer between January 2013 and December 2018 was undertaken. Sampling adequacy was assessed against standards outlined in the International Association for the Study of Lung Cancer 2009 guidelines. Multivariable logistic and Cox proportional hazards regression analyses were used to assess the impact of specific variables on adequacy and of specific variables on overall survival, respectively.

RESULTS

A total of 2380 patients were included in the study. Overall adequacy was 72.1% (n= 1717). Adherence improved from 44.8% in 2013 to 85.0% in 2018 (P< 0.001). Undergoing a right-sided resection increased the odds of adequate MLNS on multivariable logistic regression (odds ratio 1.666, 95% confidence interval [CI]: 1.385-2.003, P< 0.001). Inadequate MLNS was not significantly associated with reduced overall survival on log rank analysis (P= 0.340) or after adjustment with multivariable Cox proportional hazards (hazard ratio 0.839, 95% CI 0.643-1.093).

CONCLUSIONS

Adherence to standards improved significantly over time and was significantly higher for right-sided resections. We found no evidence of an association between adequate MLNS and overall survival in this cohort. A pressing need remains for the introduction of national guidelines defining acceptable performance.

758 Online Surgical Journal Clubs: Are They Effective?

Aim

Much of medical education has been abruptly forced online during the COVID-19 pandemic. Traditional journal clubs thrive on group interaction and debate. The aim of this project is to assess whether an online surgical journal club could replicate this experience and learning.

Method

A fortnightly, chat-based online surgical journal club with national reach was re-launched under SCALPEL (Manchester Medical School’s surgical society) with defined learning objectives, inclusion of studies from different surgical sub-specialities and a proforma to aid critical appraisal. Anonymous feedback forms were sent to participants to assess confidence in critically appraising the literature before and after attendance, and differences in means were analysed using paired t-test.

Results

32 feedback forms from participants, the majority of whom were final year medical students (34.4%) were analysed. 28.1% had previously attended a journal club. 65.6% of attendees had prior involvement in a research project which led to a publication for 18.8%, while 59.4% were interested in applying for the Academic Foundation Programme (AFP). The self-reported confidence of participants to identify the study design, interpret the results and statistical analyses; and scrutinise the strengths and weaknesses of a study increased by 12.2%, 14.7% and 15.9% respectively (p = &lt;0.001). Furthermore, 96.9% of attendees stated they would attend another online journal club in the future, with 59.4% favouring an online format.

Conclusions

Online surgical journal clubs are effective and are here to stay following the conclusion of social distancing. They have the advantage of further outreach and may encourage greater participation than traditional journal clubs.

May Measurement Month 2019: an analysis of blood pressure screening results from the United Kingdom and Republic of Ireland

In the UK, heart and circulatory diseases account for 29% of all deaths (14% through coronary heart disease and 8% through stroke). In 2015, the prevalence of hypertension was 20% in the UK and 23% in the Republic of Ireland. In 2019, 14% of people registered with a UK general practice had hypertension and yet it was the attributable risk factor for around half of all deaths from coronary heart disease or stroke. We participated in May Measurement Month 2019 to increase awareness of blood pressure (BP) measurement, and to identify the proportion of undiagnosed hypertension and degree of uncontrolled hypertension in the community. The 2019 campaign set up screening sites within the community at places of worship, supermarkets, GP surgeries, workplaces, charity events, community pharmacies, gyms, and various other public places. We screened 10194 participants (mean age 51 ± 18 years, 60% women) and found that 1013 (9.9%) were on antihypertensive treatment, while 3408 (33.4%) had hypertension. Of the 3408 participants with hypertension, only 33.5% were aware of their condition despite 98.8% having previous BP measurements. In those on antihypertensive medication, only 38.2% had controlled BP (<140 and <90 mmHg). Our UK and Republic of Ireland data demonstrate concerning levels of undiagnosed hypertension and sub-optimal BP control in many individuals with a diagnosis. This evidence supports a critical need for better systematic community and primary care screening initiatives.

Cost-effectiveness of imaging strategies to diagnose and select patients with non-obstructive coronary artery disease for statin treatment in the United Kingdom

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The project leading to this publication has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 668142.

Background

Patients with non-obstructive coronary artery disease (NOCAD) are at a higher risk of cardiovascular events compared to those with normal arteries. Plaque rupture is associated with increased adverse events and statin therapy seems to be beneficial for plaque stabilisation. Coronary Computed Tomography Angiography (CCTA) is currently the non-invasive imaging modality of choice for the morphological evaluation of NOCAD in the United Kingdom (UK). However, CCTA provides limited information regarding the vulnerability of plaques to rupture and the selection of patients for preventive statin treatment. Currently being tested on patients, Spectral Photon-Counting CT (SPCCT) may provide increased accuracy for vulnerable plaque detection and, in turn, improved selection of patients for statin treatment.

Purpose

We investigated the potential cost-effectiveness of SPCCT (compared to a set of CCTA-based strategies) in identifying NOCAD patients with rupture-prone plaques for preventive statin treatment.

Methods

A decision tree and a Markov trace were developed to model the expected outcomes (costs and quality-adjusted life-years (QALYs)) for a hypothetical UK cohort of 50-year-old male patients with stable chest pain and no history of CAD. Input data were obtained from the literature. Deterministic and probabilistic sensitivity analyses were performed. The impact of a pairwise variation of SPCCT sensitivity and specificity was analysed. Furthermore, five competing imaging strategies were compared in terms of their lifetime costs and effects: 1) CCTA and treat NOCAD based on imaging results, 2) CCTA and treat all NOCAD, 3) CCTA and do not treat NOCAD, 4) SPCCT with high specificity and treat NOCAD based on imaging results, and 5) SPCCT with high sensitivity and treat NOCAD based on imaging results.

Results

Our deterministic and probabilistic results showed that an improved imaging test would add value compared to CCTA. While increased specificity (to 95%) is favorable at a lower willingness to pay (WTP) (up to ∼£9,000 per QALY), increased sensitivity (to 95%) is more likely to be favorable at a higher WTP (∼£9,000 to £120,000 per QALY). The role of a CCTA-treat-none strategy and a CCTA-treat-all strategy is minimal and potential only at really low (&lt;£2,000 per QALY) and high (&gt;£120,000 per QALY) WTP, respectively. The uncertainty around these results is highly correlated to the uncertainty around the long-term risk for NOCAD patients to experience myocardial infarction or stroke.

Conclusion

An improved imaging test based on higher sensitivity in identifying rupture-prone coronary plaques in NOCAD patients seems to have value in guiding the decision of preventive statin treatment in the UK. However, additional data regarding the efficacy of statins and of combined treatments for NOCAD patients are needed before the cost-effectiveness of SPCCT can be precisely estimated in this population.

Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients

AIM

To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD).

MATERIALS AND METHODS

Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥ 50%) stenosis and secondarily as the presence of severe (≥ 70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard.

RESULTS

No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis.

CONCLUSION

The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role.

Transcatheter aortic valve insertion (TAVI): a review

The introduction of transcatheter aortic valve insertion (TAVI) has transformed the care provided for patients with severe aortic stenosis. The uptake of this procedure is increasing rapidly, and clinicians from all disciplines are likely to increasingly encounter patients being assessed for or having undergone this intervention. Successful TAVI heavily relies on careful and comprehensive imaging assessment, before, during and after the procedure, using a range of modalities. This review outlines the background and development of TAVI, describes the nature of the procedure and considers the contribution of imaging techniques, both to successful intervention and to potential complications.

The risk to the United Kingdom population of zinc cadmium sulfide dispersion by the Ministry of Defence during the "cold war"

OBJECTIVES

To estimate exposures to cadmium (Cd) received by the United Kingdom population as a result of the dispersion of zinc Cd sulfide (ZnCdS) by the Ministry of Defence between 1953 and 1964, as a simulator of biological warfare agents.

METHODS

A retrospective risk assessment study was carried out on the United Kingdom population during the period 1953-64. This determined land and air dispersion of ZnCdS over most of the United Kingdom, inhalation exposure of the United Kingdom population, soil contamination, and risks to personnel operating equipment that dispersed ZnCdS.

RESULTS

About 4600 kg ZnCdS were dispersed from aircraft and ships, at times when the prevailing winds would allow large areas of the country to be covered. Cadmium released from 44 long range trials for which data are available, and extrapolated to a total of 76 trials to allow for trials with incomplete information, is about 1.2% of the estimated total release of Cd into the atmosphere over the same period. "Worst case" estimates are 10 microg Cd inhaled over 8 years, equivalent to Cd inhaled in an urban environment in 12100 days, or from smoking 100 cigarettes. A further 250 kg ZnCdS was dispersed from the land based sites, but significant soil contamination occurred only in limited areas, which were and have remained uninhabited. Of the four personnel involved in the dispersion procedures (who were probably exposed to much higher concentrations of Cd than people on the ground), none are suspected of having related illnesses.

CONCLUSION

Exposure to Cd from dissemination of ZnCdS during the "cold war" should not have resulted in adverse health effects in the United Kingdom population.

Impairment of osmotically stimulated AVP release in patients with primary polydipsia

The secretion of arginine vasopressin (AVP) from the posterior pituitary is primarily and finely regulated by the osmolality of plasma. Even though a number of factors alter osmolality-induced release of AVP, there are no published data in humans that have addressed the role of chronic overhydration on this phenomenon. To address this problem we have identified eight patients with primary polydipsia using criteria not involving measurement of AVP, and have subjected them to standardized infusions of hypertonic saline. These patients had less AVP in both plasma and urine in relation to plasma osmolality than was found in normal subjects. In addition, their rate of rise of plasma and urine AVP was less than in normal subjects. Their osmotic threshold for AVP release may have been higher than normal. These data demonstrate that chronic overhydration in humans downregulates the release of AVP in response to hypertonicity. This phenomenon may explain the impairment of urine concentration in patients with primary polydipsia and emphasizes the basis of the difficulty that may occur clinically in differentiating between patients with primary polydipsia and partial central diabetes insipidus.

Gallbladder function in acromegalic patients taking long-term octreotide: evidence of rebound hypermotility on cessation of treatment

Octreotide is increasingly being used in the treatment of acromegaly. It effectively suppresses growth hormone secretion but also has inhibitory effects on gastrointestinal regulatory peptides and induces gallbladder paresis, which may predispose to gallstone formation. In nine acromegalic patients receiving long-term octreotide treatment gallbladder emptying, assessed by 99Tc-EHIDA scintigraphy after a standard fatty meal, was significantly impaired (p less than 0.005) when compared with normal healthy control subjects. Asymptomatic gallstone formation occurred in one patient who had the most severely impaired gallbladder emptying. Between 24 and 96 h after cessation of octreotide, in six of seven patients studied, gallbladder emptying had not only recovered but demonstrated significant rebound hypermotility (p less than 0.005). This finding has important implications for the administration of long-term octreotide therapy and suggests that a drug-free period each week may enable evacuation of gallbladder contents and reduce the risk of gallstone formation.

Use of T1-weighted MR imaging to differentiate between primary polydipsia and central diabetes insipidus

PURPOSE

To investigate the value of MR in differentiating patients with primary polydipsia, who have an intact neurohypophyseal system, from those with central diabetes insipidus, who have impaired synthesis and/or release of vasopressin.

METHODS

Eighteen patients with clinically significant hypotonic polyuria were diagnosed endocrinologically as having primary polydipsia or diabetes insipidus (central or nephrogenic). These patients, and 92 patients without sellar disease, were then imaged with 1.5-T, T1-weighted, thin sagittal sections without gadolinium contrast.

RESULTS

Normal hyperintense signal of the neurohypophysis was present in 90 of 92 patients without sellar disease. The signal was also present in all six patients with primary polydipsia. In contrast, the hyperintense signal was absent in all eight patients with central diabetes insipidus. Three of the four patients with nephrogenic diabetes insipidus also had an absent hyperintense signal.

CONCLUSION

T1-weighted MR may prove important in differentiating patients with central diabetes insipidus from those with primary polydipsia.

A comparison of measurements of lean body mass derived by bioelectrical impedance, skinfold thickness and total body potassium. A study in obese and non-obese normal subjects

The measurement of body composition is an important part of metabolic and epidemiological research, but most currently available methods are complex and expensive. We have, therefore, compared measurements of fat mass (FM) and lean body mass (LBM), obtained using a commercially available bioelectrical impedance monitor (The Holtain Body Composition Monitor) (IMP), and by measuring skinfold thickness (SFT), with values obtained by measuring total body potassium (TBK). Twenty subjects, 10 with a body mass index (BMI) less than 30 (kg m-2), (non-obese) and 10 with BMI greater than or equal to 30 (obese) took part in the study. There was a strongly significant linear relationship between LBM calculated from TBK and that calculated from impedance (IMP), in both non-obese and obese groups analysed separately (non-obese: r = 0.92; p less than 0.001 and obese: r = 0.92; p less than 0.001) and together (all: r = 0.89; p less than 0.001). LBM calculated from TBK was strongly linearly correlated with values derived from SFT for non-obese (r = 0.91; p less than 0.001) but not for obese subjects. Mean values of LBM of non-obese subjects derived by each method were not significantly different (TBK: 51.3 +/- 10.40 kg; IMP: 53.18 +/- 10.37 kg; SFT: 48.87 +/- 9.48 kg), but significant differences existed when the subjects were obese (TBK: 51.86 +/- 9.65 kg; IMP: 58.69 +/- 8.55 kg; SFT: 67.61 +/- 8.14 kg; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Total-body potassium in insulin-dependent diabetes mellitus

1. Total-body potassium and fat-free mass have been measured in 31 insulin-dependent diabetic patients and 31 age- and sex-matched normal volunteers. 2. Body mass index was significantly higher in the insulin-dependent diabetic patients (24.7 +/- 0.5 vs 23.3 +/- 0.4 kg/m2; P = 0.05). 3. Total-body potassium, uncorrected and corrected for weight and for fat-free mass, was not significantly different in the two groups (3281 +/- 141 mmol, 47.3 +/- 1.3 mmol/kg body weight, 60.9 +/- 1.0 mmol/kg fat-free mass, and 3315 +/- 143 mmol, 48.6 +/- 1.0 mmol/kg body weight, 60.4 +/- 0.8 mmol/kg fat-free mass, respectively, in diabetic patients and non-diabetic subjects). There was no relationship between blood glucose control, as assessed by glycated haemoglobin concentrations, and total-body potassium. 4. These results suggest, by contrast with previous reports, that in insulin-dependent diabetic patients, showing varying degrees of glycaemic control (glycated haemoglobin range 6.1-15.3%, mean 9.0%) that: (a) there is no significant abnormality of body potassium homoeostasis, and (b) there is no relation between total-body potassium and glycaemic control.

Thallium isotope scintigraphy and ultrasonography: comparative studies of localization techniques in primary hyperparathyroidism

Controversy exists about whether preoperative localization procedures are indicated in patients with primary hyperparathyroidism before first neck exploration. Currently, thallium subtraction scintigraphy and ultrasonography are the techniques used most frequently. This paper examines prospectively the accuracy and value of these techniques in a group of 71 patients with primary hyperparathyroidism. When considering all glands, thallium scanning produced a sensitivity of 46.6 per cent with a specificity of 91.5 per cent, compared with a sensitivity of only 21.4 per cent and specificity of 94.5 per cent for ultrasonography. Accuracy rates, for all glands, were 80 per cent and 75.7 per cent respectively. Both localization procedures were consistently ineffective in localizing adenomas weighing less than 500 mg, over 80 per cent of which went undetected by both scanning modalities. While both scans produced satisfactory results in localizing adenomas weighing more than 1 g, these adenomas should not represent a challenge to an experienced endocrine surgeon and, therefore, neither localization is recommended before first neck exploration.

The effect of pH adjustment of 0.5% bupivacaine on the latency of epidural anesthesia

pH adjustment of lidocaine and 2-chloroprocaine has been reported to decrease the latency of epidural anesthesia (EA). The effect of alkalinization of bupivacaine on onset of surgical anesthesia has not been adequately studied to date. To determine what effect raising the pH of 0.5% bupivacaine has on the latency of EA in patients undergoing lower extremity surgery, we performed a randomized, double-blind study. Forty patients were randomly divided into two groups. Group I patients received 15 ml of a local anesthetic (LA) solution containing 0.5% bupivacaine and 0.15 mEq of NaHCO3. Group II patients received 15 ml of a standard solution of 0.5% bupivacaine. Both solutions contained freshly added epinephrine (1:200,000). After injection of LA via Tuohy needle, sensory testing was conducted using a safety pin. The pH of the LA used for Group I was 6.96 +/- 0.01 and for Group II was 5.33 +/- 0.11. No statistically significant difference was found between the anesthetic parameters tested in each group. On this basis, we find no advantage of pH adjustment of 0.5% bupivacaine for EA.

Reduced concentrations of selenium in mild Crohn's disease

The concentrations of selenium, zinc, and copper were determined in whole blood, plasma, and leucocytes in 20 patients with relatively mild Crohn's disease, nine of whom were being treated with steroids, and compared with those of a control group. There was a significant decrease in the concentration of selenium in the leucocytes as well as in whole blood and plasma in the patients. Steroids seemed to affect only the concentrations of zinc and copper in plasma. The concentrations of copper and zinc in whole blood, plasma, and leucocytes in patients not taking steroids were not significantly different from those of the control group. The observations suggest that those patients with an apparently satisfactory whole body concentration of copper and zinc may still be at risk of a decrease in the body content of selenium.

Effects of tap water lead, water hardness, alcohol, and cigarettes on blood lead concentrations

A survey of middle-aged men in 24 British towns has found pronounced geographical variation in blood lead concentrations. Towns with the highest mean blood lead concentrations have soft water supplies and have the highest water lead concentrations. Individual blood lead can be considerably increased by raised household tap water lead concentrations. Mean blood lead is estimated to be 43% higher for men when the concentration of lead in first-draw domestic tap water is 100 micrograms/l compared with a zero concentration. Individual blood lead is also affected by alcohol consumption and cigarette smoking, such that on average these two life-style habits together contribute an estimated 17% to the blood concentration of lead in middle-aged men. Lead in water should be given greater priority in any national campaign to reduce lead exposure.

Effects of alcohol and smoking on blood lead in middle-aged British men

A survey of middle-aged men in 24 British towns showed a strong association between blood lead concentrations, alcohol consumption, and cigarette smoking. The association with alcohol persisted after age, social class, body mass index, cigarette smoking, water lead concentrations, and the town of residence had been taken into account. There was an independent but less pronounced association between cigarette smoking and blood lead concentrations after adjustment for the other factors. The possible mechanisms include a decreased excretion of lead due to alcohol-induced hepatic dysfunction and an increased lead intake from cigarette smoking. These findings have implications for widespread measurement of blood lead concentrations in adults in the community and for all studies attempting to relate blood lead concentrations to environmental exposure.

Inherited disorders of 3-methylcrotonyl CoA carboxylation

The clinical course of 4 patients who had reduced activities of 3-methylcrotonyl CoA carboxylase (also called 3-methylcrotonylglycinuria) is described. Two children presented with a metabolic acidosis, one in the neonatal period and the other with episodes of acidosis that started in the second year of life. In the other 2 children neurological symptoms were prominent, one having infantile spasms and the other developmental regression with a skin rash and alopecia. Three of the children responded well to oral biotin and dietary protein restriction but the fourth, despite a biochemical response to biotin, has a severe neurological handicap. The clinical presentation of inborn errors of 3-methylcrotonyl CoA carboxylase is variable. Metabolic acidosis may not be conspicuous and instead neurological features may predominate.

Thyroid-stimulating immunoglobulins in ophthalmic Graves' disease

Thyroid-stimulating immunoglobulins (TSI) have been detected by receptor assay in the sera of 43% of patients with ophthalmic Graves' disease. Comparison of the receptor assay studies with thyroid function tests indicated that in several patients the antibodies detected by receptor assay were biologically inactive. In other patients, thyroid function appeared to be under TSI control with hyperthyroidism prevented by autoimmune destruction of the thyroid.

Use of creatine kinase for detecting severe X-linked muscular dystrophy carriers

Women thought to be at risk of being carriers of Duchenne muscular dystrophy were given "odds" against their having an affected child. These were calcuated from a combination of the genetic risk from the family history and an estimation of the biochemical risk from measuring the serum creatine kinase concentration. The women were told the actual risk estimate and it was put into perspective for them as a high, medium, or low risk. Of 25 women at high risk six have had children, all girls; the two in the medium-risk group have had no children; and the 46 women at low risk have had 19 boys and 25 girls. None of the boys has the disease. With detailed counselling most potential carriers of this disease reach decisions in child bearing that are in line with their degree of risk.