An outbreak involving extensive transmission of a virulent strain of Mycobacterium tuberculosis

BACKGROUND AND METHODS

From 1994 to 1996, there was a large outbreak of tuberculosis in a small, rural community with a population at low risk for tuberculosis. Twenty-one patients with tuberculosis (15 with positive cultures) were identified; the DNA fingerprints of the 13 isolates available for testing were identical. To determine the extent of transmission, we investigated both the close and casual contacts of the patients. Using a mouse model, we also studied the virulence of the strain of Mycobacterium tuberculosis that caused the outbreak.

RESULTS

The index patient, in whom tuberculosis was diagnosed in 1995; the source patient, in whom the disease was diagnosed in 1994; and a patient in whom the disease was diagnosed in 1996 infected the other 18 persons. In five, active disease developed after only brief, casual exposure. There was extensive transmission from the three patients to both close and casual contacts. Of the 429 contacts, 311 (72 percent) had positive skin tests, including 81 [corrected] with documented skin-test conversions. Mice infected with the virulent Erdman strain of M. tuberculosis had approximately 1000 bacilli per lung after 10 days and about 10,000 bacilli per lung after 20 days. In contrast, mice infected with the strain involved in the outbreak had about 10,000 bacilli per lung after 10 days and about 10 million bacilli per lung after 20 days.

CONCLUSIONS

In this outbreak of tuberculosis, the growth characteristics of the strain involved greatly exceeded those of other clinical isolates of M. tuberculosis. The extensive transmission of tuberculosis may have been due to the increased virulence of the strain rather than to environmental factors or patient characteristics.

Effect of temperature and pH adjustment of bupivacaine for intradermal anesthesia

To determine the effects of warming and buffering of 0.5% bupivacaine on the pain associated with intradermal injection and the time of onset of anesthesia, 40 adult volunteers were entered into a randomized, double-blind study conducted at a community teaching hospital. The three-part study compared room temperature (20 degrees) bupivacaine buffered to a pH of 7.1 with the following solutions: buffered bupivacaine warmed to 37 degrees C, unbuffered bupivacaine at room temperature, and unbuffered bupivacaine warmed to 37 degrees C. The same crossover protocol was followed for each part of the study. Subjects received 0.5-mL intradermal injections through 27-gauge needles over 30 seconds, one study solution in each forearm. Immediately after each injection, pain was assessed using a 100-mm visual analog pain scale. The time of onset of anesthesia (loss of intradermal sensation to pinprick) was measured by stopwatch. The mean perceived pain score for the warm buffered bupivacaine (51 mm) was significantly lower than for the room temperature buffered solution (63 mm, P = .003). Similarly, there was a statistical difference between the room temperature buffered and unbuffered solutions (65 v 78 mm, P < .001). The differences in mean pain scores for the room temperature buffered bupivacaine, compared with the other three solutions, suggest that warming and buffering have an additive effect. In this model, the latency of action of bupivacaine was not affected by alkalinization. However, warming bupivacaine to 37 degrees C reduced the time of onset to intradermal anesthesia by 12.1 seconds (95% confidence interval, 0.6 to 23.6). These results suggest that warming is more effective than buffering to reduce the pain of infiltration of bupivacaine and the time of onset of intradermal anesthesia.

The insulin-like growth factor and binding protein axis in children with end-stage liver disease before and after orthotopic liver transplantation

Over 50% of children with established cirrhosis have evidence of growth failure and malnutrition. Orthotopic liver transplantation (OLT) is a successful treatment for many children and leads to improved growth and nutrition. Most of the anabolic actions of GH are mediated through the generation of the mitogenic polypeptide insulin-like growth factor-I (IGF-I). Although this is synthesised ubiquitously, the bulk of circulating IGF-I is derived from the liver. The actions of IGF-I are modulated by a family of at least six high-affinity binding proteins (IGFBPs). Growth failure in end-stage liver disease, both before and after OLT, may result from abnormalities in the IGF-IGFBP axis. Children who had undergone successful OLT were studied before and after OLT. Anthropometry was measured by standard techniques. Serum IGFs, IGFBPs and acid labile subunit (ALS) were measured by RIA, IRMA, ELISA, Western ligand and immunoblotting. The most severely affected anthropometric parameters were skin fold thickness and mid-arm circumference. After OLT there was a marked improvement in these parameters. Chronic liver disease was characterised by low serum IGF-I, IGF-II, IGFBP-3 and ALS levels with raised IGFBP-1 and -2 levels. Serum IGFBP-1 and -2 were negatively correlated with pre-OLT anthropometric parameters. After OLT, there was a rapid normalisation of serum IGF-I, while IGF-II and IGFBP-3 overshot to supranormal levels. ALS levels post-OLT remained below control levels. By 3 years post-OLT, IGFBP-3 had fallen to levels which were insignificantly different from controls. IGFBP-1 fell but remained above normal, while there was no significant change in IGFBP-2. Growth post-OLT correlated positively with serum IGF-I and negatively with IGFBP-1. In conclusion, chronic liver disease is associated with marked changes in body composition. These changes are associated with and may be caused by an impaired generation of IGF-I and altered production of IGFBPs. After OLT there is a marked improvement in growth associated with partial normalisation of the IGF-IGFBP axis. However, there are persistent abnormalities in this axis which may explain growth failure post-OLT.

Hepatic growth hormone receptor, insulin-like growth factor I, and insulin-like growth factor-binding protein messenger RNA expression in pediatric liver disease

Major changes in serum levels of insulin-like growth factor I (IGF-I) and IGF-binding proteins (IGFBPs) occur in children with end-stage liver disease in association with changes in body composition. We hypothesized that these changes would be associated with changes in hepatic messenger RNA (mRNA) expression. Eleven children with end-stage extrahepatic biliary atresia and 11 controls (liver donors) were studied. Serum samples were obtained from the children with biliary atresia immediately before orthotopic liver transplantation. Serum IGF-I, IGFBP-1, and IGFBP-2 levels were measured by radioimmunoassay, and IGFBP-3 by immunoradiometric assay. In both groups, growth hormone receptor mRNA expression was examined by quantitative reverse transcription-polymerase chain reaction, IGF-I mRNA expression by ribonuclease protection assay, and IGFBP-1 to -4 mRNA expression by Northern analysis. Growth hormone receptor and IGF-I mRNA levels were reduced 1.7-fold (P = .003) and 9.6-fold (P = .0001) in biliary atresia compared with levels in controls. Despite increased serum IGFBP-1 levels and reduced IGFBP-3 levels in biliary atresia, there was no change in either IGFBP-1 or IGFBP-3 mRNA expression. In contrast, serum levels and mRNA expression of IGFBP-2 were increased 1.6-fold (P = .003) and twofold (P = .0001), respectively, compared with controls. Gene expression did not correlate with liver dysfunction or body composition. Changes in growth hormone receptor and IGF-I mRNA expression may account for the reduction in serum IGF-I found in pediatric liver disease. In contrast, the marked alteration in circulating IGFBP levels was not accompanied by changes in hepatic IGFBP gene expression, suggesting that posttranslational mechanisms may be important.

Effectiveness of an organized follow-up system for elder patients released from the emergency department

OBJECTIVES

To determine whether an effective telephone callback system can be successfully implemented in a busy ED and to quantify the benefits that can be obtained related to the follow-up care of elder patients.

METHODS

This was a prospective, cohort study conducted at a community teaching hospital during a 6-month period. Consecutive patients > or = 60 years old and released from the ED were selected for telephone follow-up. Calls were made by a research nurse within 72 hours after the patient's ED visit. Follow-up information included current medical status, problems encountered during the ED visit, compliance, and impact of the illness on self-care capabilities.

RESULTS

Seventy-nine percent (831/1,048) of the patients selected for telephone follow-up were successfully contacted. The calls lasted an average of 4 +/- 2.5 minutes. Although 94% (778/831) of these patients had a regular physician, 14% failed to make their recommended follow-up arrangements. Compliance was significantly improved when a follow-up physician was contacted during the patient's ED visit. Approximately 96% of the patients were either satisfied or very satisfied with their ED care. However, 13% (109/831) had moderate deterioration in their ability to care for themselves. Of the patients contacted, 333 (40%) required further clarification of their home care instructions, 31 were advised to return to the ED for reevaluation, and 26 were referred to a medical social worker for psychosocial concerns.

CONCLUSION

A telephone callback system is a feasible and effective method to improve follow-up care of elder patients released from the ED.

Identifying victims of elder abuse and neglect: a training video for prehospital personnel

INTRODUCTION

The majority of prehospital emergency medical services (EMS) personnel lack specific training relating to elder abuse and neglect.

OBJECTIVES

To develop and test an audio-visual training program that focuses on the identification and reporting of domestic violence in the elderly.

METHODS

A videotape was designed to be used as a 45-minute training course for prehospital personnel using one-half inch, super-VHS recording. A convenience sample of 60 EMS personnel working in Kent County then were asked to evaluate the videotape program. Each volunteer completed a pre-test on elder abuse and neglect, watched the 45-minute videotape, and then answered 12 questions on a post-test.

RESULTS

Participants had an average of 12.4 years (range: 1-30 years) prehospital emergency-care experience. Only four (7%) could recall any previous training relating to elder abuse or neglect during their careers. Although the prevalence of elder abuse in their community was described as "rather rare" by most (60%) of the subjects, 85% (51/60) had seen a suspected case of elder abuse or neglect during their careers; 47% (28/60) had seen a case during the past six months. Only 29% of these suspected cases were reported to county authorities. Approximately 40% of the questions on the pre-test were answered correctly (mean score, 4.8 +/- 3.0). In comparison, 83% of the questions on the post-test were answered correctly (10.0 +/- 3.0). Although participants had a number of suggestions to improve the video program, 78% (47/60) expected this material to change the way they will evaluate elderly patients in the future.

CONCLUSION

Prehospital personnel do not feel confident identifying or reporting victims of elder abuse or neglect. A videotape training program may be an effective way of presenting this information as a means of continuing education.

Assessing bedside cardiologic examination skills using "Harvey," a cardiology patient simulator

OBJECTIVE

To assess the cardiovascular physical examination skills of emergency medicine (EM) housestaff and attending physicians.

METHODS

Prospective, cohort assessment of EM housestaff and faculty performance on 3 valvular abnormality simulations (mitral regurgitation, mitral stenosis, and aortic regurgitation) conducted on the cardiology patient simulator, "Harvey." Participants examined each of the 3 study disease simulations and proposed a diagnosis (session I). They were then given a cardiac examination form and repeated the programmed simulations (session II). The examination form was used to prompt physicians to interpret 23 separate cardiac findings for each simulation in a multiple-choice format.

RESULTS

Forty-six EM housestaff (PGY1-3) and attending physicians were tested over a 2-month study period. Physician responses did not differ significantly among the different levels of postgraduate training. The overall correct response rates for participants were 59% for aortic regurgitation, 48% for mitral regurgitation, and 17% for mitral stenosis. For aortic regurgitation, recognition of a widened pulse pressure and recognition of diastolic decrescendo murmur were associated with a correct diagnosis (p < 0.01). For mitral regurgitation, correct assessment of the contour of the holosystolic murmur predicted a correct diagnosis (p < 0.001). For mitral stenosis, proper characterization of the mitral area diastolic murmur predicted a correct diagnosis (p < 0.001).

CONCLUSION

Housestaff and faculty had difficulty establishing a correct diagnosis for simulations of 3 common valvular heart diseases. However, accurate recognition of a few critical signs was associated with a correct diagnosis in each simulation. Training programs may need to focus attention on selected key components of the cardiovascular examination to facilitate teaching of physical diagnosis.

Elder mistreatment: national survey of emergency physicians

To determine the perceived magnitude of elder mistreatment, physician awareness of applicable state laws, and the barriers to reporting suspected cases, we surveyed a random sample of 3,000 members of the American College of Emergency Physicians in the United States. Survey questions included practice characteristics, number and type of suspected cases of elder mistreatment seen in the ED, number of cases actually reported, and reasons for not reporting abuse. Physicians were also asked about the availability of elder-mistreatment protocols and their familiarity with local laws and reporting requirements. We received 705 completed surveys, for a response rate of 24%. Most physicians (52%) described elder mistreatment as prevalent but less so than spouse or child abuse. The respondents had evaluated a mean of 4 +/- 8 (range, 0 to 93) suspected cases of elder mistreatment in the preceding 12 months; approximately 50% were reported. Only 31% of emergency physicians reported having a written protocol for the reporting of elder mistreatment, and physicians were generally not familiar with applicable state laws. Twenty-five percent were able to recall educational content pertaining to elder mistreatment during their emergency medicine residencies. Most physicians were not certain or did not believe that clear-cut medical definitions of elder abuse or neglect exist (74%); that emergency physicians can accurately identify cases of mistreatment (58%); or that their states had sufficient resources to meet the needs of victims (92%). These results suggest that practicing emergency physicians are not confident in identifying or reporting geriatric victims of abuse or neglect. This lack of confidence may reflect inadequacies of training, research, and continuing education with regard to mistreatment of older people.

Patient transfer from nursing home to emergency department: outcomes and policy implications

OBJECTIVE

To describe the process and outcomes of nursing home (NH) residents transferred to hospital EDs.

METHODS

This was a prospective, observational study conducted at 2 Midwestern community teaching hospitals during a 12-month period. All elder patients (> 64 years of age) transferred to hospital EDs from regional NHs were eligible for the study. Hospital records were used to abstract relevant descriptive and clinical data. Need for ambulance use was graded prospectively using 3 categories of urgency developed in other studies. Transfers were considered "appropriate" based on outcome measures or if the problem necessitated diagnostic and/or therapeutic procedures not available in the NH. Transfer documentation was evaluated using a standardized 18-item checklist.

RESULTS

A total of 709 consecutive NH patients made 1,012 ED visits. Their mean age was 83.4 years (range 65-100); 76% were female. The majority of patients (94%) were transferred by ambulance. Ambulance transfer was classified as emergent (16% of patients), urgent (45%), or routine (39%). There were 319 (45%) patients subsequently admitted to the hospital. Approximately 77% (546/709) of the NH transfers were considered appropriate by the emergency physician (EP). Sixty-seven patients (10%) were transferred without any documentation. For those patients with transfer documentation, 6 common discrepancies were identified.

CONCLUSION

Although the majority of NH transfers in this population were appropriate, many patients were transferred without adequate documentation for the EP.

Unrecognized pregnancy in the overdosed or poisoned patient

A 22-year-old woman was found in bed unresponsive and hypotensive after an apparent overdose. Subsequent workup in the emergency department identified a ruptured ectopic pregnancy and extensive hemoperitoneum. A significant delay occurred when emergency physicians excluded the possibility of pregnancy because of the patient's normal menstrual history. A qualitative serum or urine pregnancy test is recommended in all women of child-bearing age who present with poisoning or drug overdose.

Treatment of coronary artery disease in an anomalous coronary artery by placement of an intracoronary stent

We report the use of coronary stenting to treat disease in an anomalous coronary artery. The patient had a single coronary artery with anomalous left anterior descending artery arising from the right sinus of Valsalva and coursing between the aorta and pulmonary artery. Although balloon angioplasty has been used in patients with anomalous coronary arteries, this is the first report of stent placement in this circumstance.

Insulin-like growth factor binding protein concentration and post-translational modification in embryological fluid

Levels of proteolytic activity directed against insulin-like growth factor binding protein 3 (IGFBP-3) and the distribution of phosphorylated isoforms of IGFBP-1 were assessed in matched sample sets of maternal serum, coelomic fluid and amniotic fluid from 21 pregnancies at 6-12 weeks gestation. In addition, concentrations of immunoreactive IGFBP-1 to -3, insulin-like growth factor (IGF)-I and -II were determined in all three compartments in 21 pregnancies, and in coelomic fluid and maternal serum in 58 pregnancies. IGF-I concentrations were highest in maternal serum and similarly low in coelomic and amniotic fluid. IGF-II concentrations were also highest in maternal serum but easily detectable in coelomic fluid where concentrations showed a significant correlation with gestational age. IGFBP-1 concentrations were higher in coelomic fluid than in either maternal serum or amniotic fluid and showed a significant correlation with gestational age in this compartment. Analysis of IGFBP-1 phosphoforms showed clear differences in phosphorylation of IGFBP-1 between groups with maternal serum containing predominantly the phosphorylated forms and coelomic fluid almost exclusively the non-phosphorylated form. First trimester amniotic fluid IGFBP-1 was barely detectable and appeared non-phosphorylated. These findings suggest that the high IGF-II concentrations and lack of inhibitory phosphoforms of IGFBP-1 in coelomic fluid could potentially enhance mitogenic activity in the early human gestational sac. IGFBP-2 concentrations were high in coelomic fluid compared with maternal serum whereas coelomic fluid IGFBP-3 concentrations were intermediate, easily detectable and correlated strongly with gestational age. Protease activity was far less in coelomic fluid than in matched maternal serum samples. Marked differences in both concentrations and post-translational modification of IGFBPs in maternal serum compared with embryonic fluid suggest different regulatory pathways.