Clonidine toxicity in an adolescent patient.

Clonidine is a central acting a2-agonist used primarily as an antihypertensive agent. Recently, it has been used for the treatment of attention deficit hyperactivity disorder in children and adolescents. When taken in excess, it can produce profound CNS depression, apnea, bradycardia and hypotension. A transient period of hypertension can sometimes occur. Treatment is primarily supportive, including respiratory support, atropine for bradycardia, and fluids and dopamine for hypotension. The CNS depression sometimes responds to naloxone. Young children are very sensitive to the toxic effects of clonidine. A case of an 11 year old adolescent who took an overdose of his clonidine is described to illustrate the toxicity of this agent.

Prospective identification of myocardial stunning using technetium-99m sestamibi-based measurements of infarct size.

OBJECTIVES: We sought to prospectively identify patients with stunning and hyperkinesia at hospital discharge on the basis of mismatches between left ventricular (LV) function and infarct size as assessed by technetium-99m (Tc-99m) sestamibi perfusion tomographic imaging. BACKGROUND: Mechanical indexes of LV function may not accurately reflect myocardial damage after acute myocardial infarction (MI) because of myocardial stunning and compensatory hyperkinesia in noninfarct-related territories. Myocardial perfusion techniques are unaffected by these variables. METHODS: Eighty-four patients with acute MI underwent hospital admission and discharge Tc-99m-sestamibi tomographic imaging. Global LV ejection fraction (LVEF) was measured at hospital discharge and 6 weeks later. The perfusion defect size was quantified and expressed as a percentage of the LV. The discharge perfusion defect, which is a measure of infarct size, was used to predict the 6-week LVEF for each patient based on a previously reported regression equation. Patients were classified into one of three groups depending on whether their LVEF at hospital discharge fell within, above or below one standard error (6.8 LVEF points) of the predicted 6-week LVEF. RESULTS: There were 48 patients classified as having a "match" between function and infarct size; these patients demonstrated no significant change in LVEF at 6 weeks. There were 21 patients (25%) classified as "mismatch stunned" who had discharge LVEFs lower than those predicted by infarct size. These patients demonstrated a significant improvement in mean LVEF at 6 weeks (mean [+/-SD] discharge LVEF 0.41 +/- 0.08, 6-week LVEF 0.47 +/- 0.10; p = 0.003). Fifteen patients (18%) were classified as "mismatch-hyperkinetic." The mean LVEF for these patients significantly declined at 6 weeks (discharge LVEF 0.64 +/- 0.06, 6-week LVEF 0.58 +/- 0.09; p = 0.002). There was a marked increase in LVEF within the infarct zone (8 +/- 15 LVEF points; p = 0.03) for patients predicted to have stunning and a marked decline in LVEF outside the infarct zone (9 +/- 15 LVEF points; p = 0.06) in patients predicted to have hyperkinesia. Both discharge LVEF (p < 0.0001) and group classification (p = 0.005) were independent predictors of LVEF 6 weeks later. CONCLUSIONS: Perfusion imaging with Tc-99m-sestamibi can identify post-MI patients at hospital discharge in whom LV function is discordant with the measured infarct size. Patients with stunning have late increases in LVEF; patients with hyperkinesia have late decreases. This methodology, performed at discharge, is predictive of late changes in LV function.

Bleeding and thromboembolism during anticoagulant therapy: a population-based study in Rochester, Minnesota.

OBJECTIVE: To estimate the incidence of and identify risk factors for hemorrhage and thromboembolism during long-term anticoagulant therapy. DESIGN: We conducted a population-based retrospective cohort study of all residents of Rochester, Minnesota, in whom a course of warfarin therapy intended to last for more than 4 weeks was initiated between Sept. 1, 1987, and Dec. 31, 1989. METHODS: Medical records were reviewed, and pertinent data were compiled. All bleeding complications were classified as minor or major on the basis of the bleeding severity index, and thromboembolic events were classified as major if they were fatal or life-threatening. Cumulative incidences of adverse events were analyzed statistically. RESULTS: During the study period, 261 patients had incident courses of anticoagulation (52% were male, 61% were 65 years of age or older, and 31% were 75 years of age or older), with 221 patient-years of warfarin exposure. The primary indications for anticoagulation were venous thromboembolism (39%); stroke or transient ischemic attack (21%); atrial fibrillation (11%); and coronary artery disease, procedures for coronary artery disease, or cardiomyopathy (7%). The cumulative incidence of major hemorrhage at 1, 3, 12, and 24 months was 1.6%, 3.3%, 5.3%, and 10.6%, respectively, and of major or minor thromboembolic events was 2.3%, 5.0%, 7.4%, and 13.1%, respectively. In multivariate analysis, (1) a malignant condition was significantly associated with major hemorrhage; (2) malignant disease and history of peptic ulcer were significantly associated with the combined outcome of major or minor hemorrhage; and (3) malignant disease was significantly associated with any thromboembolism. Age, sex, atrial fibrillation, history of gastrointestinal hemorrhage, history of peptic ulcer, alcohol abuse, hypertension, stroke, and the Charlson comorbidity index were not significantly associated with major hemorrhage. CONCLUSION: In this population-based study, including a high proportion of elderly patients, malignant disease at initiation of warfarin anticoagulation was significantly associated with both major hemorrhage and any thromboembolism. Advanced age is not a contraindication to anticoagulant therapy.

Cocaine and chest pain: clinical features and outcome of patients hospitalized to rule out myocardial infarction.

OBJECTIVE: To investigate the clinical features, electrocardiographic findings, and hospital course in patients admitted with acute chest pain temporally related to cocaine use. DESIGN: Retrospective data analysis. SETTING: A 485-bed county hospital. PATIENTS: One hundred and one consecutive patients with cocaine-related chest pain admitted to the hospital to rule out myocardial infarction. MEASUREMENTS AND MAIN RESULTS: The quality of the chest pain frequently suggested myocardial ischemia. Dyspnea was common (56%). The onset of chest pain occurred during cocaine use in 21% of patients, within 1 hour of use in 37%, and after 1 hour of use in 42%. Admission electrocardiographic findings were interpreted as normal in 32% of patients; as acute myocardial injury in 8%; as early repolarization variant in 32%; as left ventricular hypertrophy in 16%; and as "other" in 12%. Forty-three percent of patients had ST-segment elevation meeting the electrocardiographic criteria for use of thrombolytic therapy, but such elevation was usually due to the early repolarization variant. The initial total creatine kinase was elevated more than 3.3 mu kat/L (200 U/L) in 43% of patients, and an elevated total creatine kinase was recorded at some time during the hospital course in 47% of patients. The creatine kinase MB fraction was less than 0.02 in all patients. Myocardial infarction was ruled out in all patients. No patient experienced in-hospital cardiovascular complications. CONCLUSION: The quality of acute chest pain related to cocaine use is indistinguishable from that experienced in acute myocardial ischemia. Abnormal or normal variant electrocardiographic findings are common in patients with chest pain related to cocaine use, but nevertheless the incidence of acute myocardial infarction is low. The ST-segment and T-wave changes can mimic acute myocardial injury and are most likely normal findings in young black men that can be readily recognized in the emergency department. Most of these patients do not require admission to an intensive care unit.

Variability of different methods for measurement of ECG intervals and ECG interval temporal variation.

We found significant variation within each computer and cardiologist method for measurement of the ECG waveform intervals. Comparison between methods revealed that the HP system had a smaller variability than the MAC or the cardiologist, and that the MAC had a smaller variability than the cardiologist. No variability was found when a cardiologist used different paper trace speeds. Using HP measurements, we found a significant difference in ECG intervals over time, which was greater than the variability found within the method at baseline. The delineation of variability within and between ECG interval measurement methods may allow more reliable application of ECG interval changes in the therapeutic medical management of patients and prevention of side effects from drugs that affect ECG intervals. Computerized ECG waveform analysis is a widely available technology whose full role in therapeutic medical management may not be appreciated.

Epidemiology of ovine listeriosis in Great Britain.

A retrospective study of 75 sheep flocks affected with listeriosis during January to June 1982 was made. Seven flocks experienced more than one form of listeriosis. Encephalitis was the commonest form, occurring in 60 flocks, and only lambs were affected in 10 of these flocks. In the remaining 50 flocks only single cases in adults were recorded in eight flocks. The mean attack rate for encephalitis in adults was 2.5 per cent. Listeric abortions occurred in 18 flocks and was the only form of listeriosis in 13 flocks. Silage was fed in 59 of the affected 60 flocks. A significant association between silage feeding and the development of listeric encephalitis was found in these flocks with the estimated relative risk being 3.8. Winter housing was not found to be associated with the development of listeric encephalitis.

Experimental infection of pregnant ewes with Listeria monocytogenes.

Eight 18-month-old ewes were infected orally with Listeria monocytogenes between 77 and 91 days of pregnancy. Only one ewe aborted, 10 days after the first infecting dose, at 94 days of gestation; L monocytogenes was isolated from several sites in both its aborted fetuses. Two days after the first infecting dose all the ewes exhibited mild illness and pyrexia lasting for two to three days but the ewe which aborted was seriously ill until nine to 10 days after aborting. Agglutination tests carried out on 2-mercaptoethanol reduced sera revealed a strong immunological response in all the infected ewes but in the ewe which aborted this response was delayed. Four uninfected ewes which were kept as controls remained healthy throughout the experiment and showed no evidence of 2-mercaptoethanol resistant antibodies to L monocytogenes. Growth retardation lines, occurring at the time of and after experimental infection, were found in the bones of 14 of 17 newborn lambs in both the infected and control groups; in the aborted lambs these lines occurred before the infection.

Listeria monocytogenes infection in bovine mastitis.

Listeria monocytogenes type 4 was isolated from milk of a cow affected with mastitis in the left fore quarter. Histological examination revealed a severe suppurative mastitis with eosinophil leucocytes predominating among the inflammatory cells. The findings and the public health aspect of the condition are discussed.

Nutritional myodegeneration in dairy cows.

A syndrome is described in which parturient dairy cows showed clinical signs consistent with milk fever but failed to respond to conventional therapy. The affected cows were reluctant to walk, moved stiffy and in severe cases became recumbent. The condition was apparently precipitated by low vitaimin E and selenium intake, stress of pregnancy and in one outbreak erratic feeding. Skeletal and cardiac myodegeneration were observed grossly and histologically but an almost full term fetus from an affected cow showed no muscle lesions. A high incidence of retained placentae was also recorded.

Listeria monocytogenes in "oven-ready" poultry.

Listeria monocytogenes was isolated from 10 out of 68 "oven-ready" poultry (ie, 14-7 per cent) purchased at 26 different shops and supermarkets. The organisms belonged to type 4 and 1/2; from one chicken both serotypes were isolated.

Testicular scanning: a new modality for the preoperative diagnosis of testicular torsion.

A simple, safe and rapid scanning procedure using 99-m technetium is described for the diagnosis of torsion of testicles. The procedure is especially useful in the adult with an enlarged scrotum of recent origin in whom the surgeon cannot clinically differentiate torsion of the testicle from epididmitis. It is not suggested that this procedure replace immediate scrotal exploration in the acutely illpatient.