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Biomedical subjects

Andrew D Perron

Publications and source records attributed to Andrew D Perron.

At least 37 records · Page 2Linked to original sources
PubMed2003

Orthopedic pitfalls in the ED: osteomyelitis.

Osteomyelitis can present to the emergency department as an acute, subacute, or chronic orthopedic concern. The presentation can range from subtle, as with acute hematogenous osteomyelitis in the pediatric patient population, to obvious, as with the diabetic patient who presents with a foot ulcer overlying exposed bone. Accurate early diagnosis and prompt treatment, whether with antibiotics, debridement, or both, are important in helping determine the ultimate outcome in this potential orthopedic pitfall. We review here the clinical presentation, diagnostic techniques, and management options for osteomyelitis that are applicable to the emergency practitioner.

Aged↗
PubMed2003

The Brugada syndrome.

Brugada syndrome describes the syndrome of sudden cardiac death in the setting of the following electrocardiographic findings: right bundle branch block pattern with ST-segment elevation in the right precordial leads. The right bundle branch block may be incomplete while the ST segment elevation is minimal. The electrocardiographic findings are not constant. Patients suspected of having Brugada syndrome should be promptly referred for electrophysiological testing and treatment. Rapid referral and placement of an implantable cardioverter defibrillator (ICD) is associated with an excellent prognosis, whereas failure to diagnose this condition is associated with a high risk for sudden death. Therefore, it is imperative that all emergency physicians be familiar with the typical ECG manifestations of Brugada syndrome. Three illustrative cases are presented with a review of the syndrome.

Adult↗
PubMed2002

Serial electrocardiography.

During the past 15 years, medicine has witnessed several important advances in coronary artery reperfusion therapy for acute myocardial infarction (AMI). Both percutaneous transluminal coronary angioplasty (PTCA) and thrombolytic therapy have made significant advances in the early treatment of the AMI patient. Given both the shown benefit of these treatment modalities and the cardiac injury that they can prevent, it behooves the emergency physician (EP) to make a timely diagnosis of AMI to restore adequate perfusion and to salvage the maximum amount of myocardium. A correct diagnosis is dependent on EP expertise in the evaluation of the chest pain patient--in large part, the electrocardiogram.

Adult↗
PubMed2002

Reciprocal ST segment depression: impact on the electrocardiographic diagnosis of ST segment elevation acute myocardial infarction.

Acute myocardial infarction (AMI) is one of many causes of electrocardiographic ST segment elevation (STE) in ED chest pain (CP) patients; at times, the electrocardiographic diagnosis may be difficult. Coexistent ST segment depression has been reported to assist in the differentiation of non-infarction causes of STE from AMI-related ST segment elevation. The objective was to determine the effect of AMI diagnosis on the presence of STD among ED CP patients with electrocardiographic STE. Adult CP patients with electrocardiographic STE in at least 2 anatomically distributed leads were reviewed for the presence or absence of ST segment depression in at least 1 lead and separated into 2 groups, both with and without ST segment depression. A comparison of the 2 groups was performed in 2 approaches: all STE patients and then only with STE patients who lacked confounding electrocardiographic pattern (bundle branch block [BBB], left ventricular hypertrophy [LVH], or right ventricular paced rhythm [VPR]). All patients in the study underwent prolonged observation in the ED (at least 8 hours) with 3 serial troponin T determinations and 3 electrocardiograms (ECG). AMI was diagnosed by abnormal serum troponin T values (>0.1 mg/dL); electrocardiographic STE diagnoses of non-AMI causes were determined by medical record review. There were 171 CP patients with STE were entered in the study with 112 (65.5%) individuals show ST segment depression. When considering all study patients, ST segment depression was present at statistically equal rates in AMI and non-AMI situations (P = NS). The sensitivity, specificity, positive predictive value, and negative predictive value for the electrocardiographic diagnosis of AMI were 63%, 34%, 30%, and 67%, respectively. Patients with confounding patterns (LVH 46, BBB 19, and VPR 6) were removed from the analysis group, leaving 100 patients for analysis; 38 of these patients had ST segment depression. When considering this group of study patients, ST segment depression was present significantly more often in AMI patients (P <.0001). The sensitivity, specificity, positive predictive value, and negative predictive value for the electrocardiographic diagnosis of AMI were 69%, 93%, 93%, and 71%, respectively. Clinical diagnoses were as follows: 56 AMI, 50 USAP, and 65 noncoronary syndrome. When all CP patients with electrocardiographic STE are considered, the presence of ST segment depression is not helpful in distinguishing AMI from non-AMI. If one considers only patterns which lack electrocardiographic ST segment depression caused by altered intraventricular conduction, the presence of ST segment depression strongly suggests the diagnosis of AMI. In these cases, reciprocal ST segment depression is of considerable value in establishing the electrocardiographic diagnosis of STE AMI.

Adult↗
PubMed2002

Orthopedic pitfalls in the ED: pediatric growth plate injuries.

Musculoskeletal injuries are frequently the reason children and adolescents seek care in the emergency department. In the skeletally immature patient, injury to the open growth plate can occur. When missed or mismanaged, these injuries can result in growth plate arrest. The emergency physician needs to remain vigilant for these injuries. This review article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency physician.

Adolescent↗
PubMed2002

Orthopedic pitfalls in the ED: fight bite.

Clenched fist injuries to the mouth ("fight bite") are notorious for being the worst human bites. These are often treated as minor injuries, without the recognition that the joint capsule, the extensor tendon, or the deep fascial spaces may have been violated and contaminated with oral bacteria. Significant morbidity can result from late presentation or inadequate initial management. The emergency physician needs to remain vigilant for complications associated with closed fist injury. This review article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency physician in the treatment of fight bite.

Bites, Human↗
PubMed2002

Electrocardiographic T-wave inversion: differential diagnosis in the chest pain patient.

Inverted T waves produced by myocardial ischemia are classically narrow and symmetric. T-wave inversion (TWI) associated with an acute coronary syndrome (ACS) is morphologically characterized by an isoelectric ST segment that is usually bowed upward (ie, concave) and followed by a sharp symmetric downstroke. The terms coronary T wave and coved T wave have been used to describe these ischemic TWIs. Prominent, deeply inverted, and widely splayed T waves are more characteristic of non-ACS conditions such as juvenile T-wave patterns, left ventricular hypertrophy, acute myocarditis, Wolff-Parkinson-White syndrome, acute pulmonary embolism, cerebrovascular accident, bundle branch block, and later stages of pericarditis.

Adult↗
PubMed2002

The prominent T wave: electrocardiographic differential diagnosis.

The prominent T wave is an abnormal T-wave morphology encountered in the earliest phase of ST-segment elevation acute myocardial infarction (AMI). Prominent T waves, however, are associated with other diagnoses, including hyperkalemia, early repolarization, and left ventricular hypertrophy (LVH). This article focuses on the electrocardiographic differential diagnosis of the prominent T wave with the presentation of 4 illustrative cases. We also recommend that the designation hyperacute should refer exclusively to the prominent T waves of ST-segment elevation AMI.

Adult↗
PubMed2002

Electrocardiographic manifestations of hypothermia.

Hypothermia is generally defined as a core body temperature less than 35 degrees C (95 degrees F). Hypothermia is one of the most common environmental emergencies encountered by emergency physicians. Although the diagnosis will usually be evident after an initial check of vital signs, the diagnosis can sometimes be missed because of overreliance on normal or near-normal oral or tympanic thermometer readings. The classic and well-known electrocardiographic (ECG) manifestations of hypothermia include the presence of J (Osborn) waves, interval (PR, QRS, QT) prolongation, and atrial and ventricular dysrhythmias. There are also some less known (ECG) findings associated with hypothermia. For example, hypothermia can produce ECG signs that simulate those of acute myocardial ischemia or myocardial infarction. Hypothermia can also blunt the expected ECG findings associated with hyperkalemia. A thorough knowledge of these findings is important for prompt diagnosis and treatment of hypothermia. Six cases are presented that show these important ECG manifestations of hypothermia.

Adult↗
PubMed2002

Electrocardiographic ST segment elevation: left ventricular aneurysm.

Left ventricular aneurysm (LVA), also described as dyskinetic left ventricular segment, is defined as a localized area of infarcted myocardium that bulges outward during both systole and diastole. LVAs most often are noted after large anterior wall events but may also be encountered status after inferior and posterior wall injuries. In most cases, LVA is manifested electrocardiographically by varying degrees of ST segment elevation (STE), which may be difficult to distinguish from ST segment changes caused by acute myocardial infarction. The STE is generally associated with well-developed, completed Q waves in the anterior precordial leads, and there will not be reciprocal ST depression in the contralateral leads. This article focuses on the electrocardiographic findings useful in making the diagnosis of left ventricular aneurysm as well as distinguishing LVA from other STE syndromes.

Aged↗
PubMed2002

Orthopedic pitfalls in the ED: slipped capital femoral epiphysis.

Slipped capital femoral epiphysis (SCFE), though a relatively common disorder, is frequently missed on initial presentation. Symptoms can be vague, the physical examination unrevealing, and radiographic abnormalities subtle. Prompt diagnosis of SCFE is important, however, to improve clinical outcome. The emergency physician needs to remain vigilant for this diagnosis to avoid this orthopedic pitfall. This article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency physician in the treatment of SCFE.

Adolescent↗
PubMed2002

Orthopedic pitfalls in the ED: radiographically occult hip fracture.

Acute hip fracture is among the most commonly encountered orthopedic injuries seen by the emergency physician. The majority of these fractures can be readily diagnosed on the basis of clinical findings and plain radiographs. When initial films are negative or equivocal, but a high clinical suspicion exists for a hip fracture, additional diagnostic studies need to be performed because significant morbidity can result from ambulation on an unrecognized fracture. The emergency physician needs to remain vigilant for this potential orthopedic pitfall. This review article examines the clinical presentation, diagnostic techniques, and management options applicable to the emergency practitioner.

Aged↗
PubMed2002

Electrocardiographic manifestations of Wellens' syndrome.

Wellens' syndrome is a pattern of electrocardiographic T-wave changes associated with critical, proximal left anterior descending (LAD) artery stenosis. The syndrome is also referred to as LAD coronary T-wave syndrome. Syndrome criteria include T-wave changes plus a history of anginal chest pain without serum marker abnormalities; patients lack Q waves and significant ST-segment elevation; such patients show normal precordial R-wave progression. The natural history of Wellens' syndrome is anterior wall acute myocardial infarction. The T-wave abnormalities are persistent and may remain in place for hours to weeks; the clinician likely will encounter these changes in the sensation-free patient. With definitive management of the stenosis, the changes resolve with normalization of the electrocardiogram. It is vital that the physician recognize these changes and the association with critical LAD obstruction and significant risk for anterior wall myocardial infarction.

Coronary Stenosis↗
PubMed2002

Orthopedic pitfalls in the ED: pediatric supracondylar humerus fractures.

Supracondylar humerus fractures are the most common fracture around the elbow in the pediatric population. They are the result of a fall on an outstretched arm and are seen primarily in the first decade of life. The diagnosis of these fractures can be subtle and, if missed, can result in vascular, structural, or neurologic injuries. Prompt diagnosis and treatment of these injuries is important to improved clinical outcome. The emergency physician needs to remain vigilant for this diagnosis to avoid this orthopedic pitfall. This review article examines the clinical presentation, diagnostic technique, and management options applicable to the emergency physician in the treatment of supracondylar humerus fractures.

Child↗
PubMed2002

Electrocardiographic ST segment elevation: a comparison of AMI and non-AMI ECG syndromes.

Chest pain (CP) patients presenting to the ED may manifest electrocardiographic ST segment elevation (STE). AMI (acute myocardial infarction) is a less frequent cause of such abnormality and one of many patterns responsible for ST segment elevation in ED CP patients. We performed a retrospective comparative review of the electrocardiographic features of various STE syndromes, focusing on differences between AMI and non-AMI syndromes. The electrocardiograms (ECGs) of consecutive ED adult CP patients (with 3 serial troponin I determinations) were interpreted by 3 attending emergency physicians. These ECGs with STE represented the study population used for analysis. Various electrocardiographic features such as STE, ST segment depression (STD), STE morphology, anatomic distribution of STE, and the number of leads with STE were recorded; derived values such as total STE, total ST segment deviation, and average STE per lead were calculated. Interobserver reliability concerning STE morphology was determined. AMI was diagnosed by abnormal serum troponin I values (>0.1 mg/dL) followed by a rise and fall of the serum marker; STE diagnoses of non-AMI causes were determined by medical record review. Five hundred ninety-nine CP patients were entered in the study with 212 (35%) individuals showing STE, 55 (26%) with electrocardiographic AMI and 157 (74%) with non-AMI electrocardiographic syndromes. Anatomic location within the AMI group included 32 inferior and inferior variants, 18 anterior and anterior variants, and 5 lateral; non-AMI anatomic locations included 56 inferior and inferior variants, 98 anterior and anterior variants, and 3 lateral; anterior STE occurred significantly more often in non-AMI syndromes. Total STE was 15.3 mm in AMI patients and 7.4 mm in non-AMI patients (P =.0004). The number of leads with STE was not significantly different between the two groups, 3.4 mm in AMI and 4.1 in non-AMI syndromes. ST segment elevation per lead was not significantly different in the 2 groups, 4.4 mm in AMI versus 1.8 mm in non-AMI syndromes. Total ST segment deviation (sum of STE and STD) was significantly greater in AMI syndromes, 17.8 mm in AMI compared with 10.5 mm in non-AMI syndromes (P =.00009). The presence of STD occurred at statistically similar rates in both groups. The morphology of the STE occurred in significantly different rates between AMI and non-AMI patterns, concave more often in non-AMI patterns (P <.00001) and nonconcave more often in AMI (P <.00001). Non-AMI causes of STE account for the majority of electrocardiographic syndromes encountered in ED chest pain patients. These findings alone are not adequate to determine the electrocardiographic cause of the ST segment elevation in chest pain patients. When determining AMI versus non-AMI with the ECG, these various findings should be used in the consideration of the overall clinical picture (history, examination, and electrocardiogram) in chest pain patients with ST segment elevation.

Angina Pectoris↗
PubMed2002

Altered mental status: evaluation and etiology in the ED.

The purpose of this study was to determine the etiologies responsible for altered mental status (AMS) in an emergency department (ED) population, to gauge the diagnostic (DX) value of the various features of the clinical evaluation, and to examine patient outcomes. Prospective identification of patients with AMS followed by a retrospective review of the medical record was performed in a university hospital E among ED patients with AMS. Three hundred seventeen patients (5% of the ED patient volume) were identified with a mean age of 49 years (57% men). Descriptions of the AMS included 24% unresponsive, 46% lethargic/difficult to arouse, 12% agitated, and 18% unusual behavior. The most common discharge diagnoses accounting for AMS were neurologic (28%) and toxicologic (21%) followed by trauma (14%), psychiatric (14%), infectious (10%), endocrine/metabolic (5%), pulmonary (3%), oncologic (3%), cardiovascular (1%), gastrointestinal (1%), and renal (1%). The specific features of the clinical evaluation of greatest DX value followed by rates of positive DX finding included history of present event (51%), past medical history (43%), and physical examination (41%); features of little DX value included radiographs (16%), 12-lead electrocardiogram (7%), and various laboratory studies (chemistry panel [5%], complete blood count [1%], coagulation panel [0], urinalysis [11%]). Sixty-four percent of the patients were admitted with a mean hospital stay of 7.6 days and 9% deaths. Common causes of AMS included neurologic, toxicologic, traumatic, and psychiatric syndromes. The patient history and physical examination were most useful in DX terms; ancillary investigations were less often DX. This group represented a minority of the ED population yet rates of ED resource use, hospital admission, and death were high.

Adolescent↗
PubMed2002

Management of common stress fractures. When to apply conservative therapy, when to take an aggressive approach.

Stress fractures are an increasingly common injury in primary care patient populations. Early diagnosis and prompt conservative therapy are effective for most of these injuries. Special attention to clues from history taking and physical examination in an at-risk patient population can lead physicians to the correct diagnosis. Most stress fractures resolve with rest and progressive reintroduction of stressors, but certain injuries, such as stress fractures of the femoral neck and fifth metatarsal, have a high risk of complications and require aggressive therapy.

Decision Making↗