Biomedical subjects

R A Harrigan

Publications and source records attributed to R A Harrigan.

9 recordsLinked to original sources

PubMed2001

Diagnosis and management of bradycardia and atrioventricular block associated with acute coronary ischemia.

Bradyarrhythmias arising in the setting of myocardial infarction occur in a significant minority of patients with AMI. In the majority of cases, these abnormalities are owing to myocardial ischemia or infarction with necrosis of the cardiac pacemaker sites and/or conduction system. Other factors responsible for these bradyarrhythmias include altered autonomic influence, systemic hypoxia, electrolyte disturbances, acid-based disorders, and complications of various medical therapies. This article will focus on not only the diagnosis and management of these rhythm disturbances, but also on the pathophysiology of the arrhythmias.

Adrenergic beta-Agonists↗

PubMed2001

General pharmacologic treatment of acute myocardial infarction.

The general pharmacotherapeutic issues surrounding AMI are complex and expanding, especially with regard to treatment aimed at the [table: see text] culprit, coronary atherosclerotic thrombus. Basic, well-established therapy includes the routine administration of oxygen, nitroglycerin, aspirin, and at times morphine, with selected cases invoking caution with respect to these agents (e.g., nitroglycerin and the risk of hypotension in right ventricular infarction; contraindication to nitrolycerin in patients on sildenafil). Cardioprotective agents, especially beta-adrenergic antagonists, should be considered early in light of their demonstrated benefit; others, such as ACE inhibitors, need not be administered in the ED. Heparin, both UFH and the newer LMWHs, have well-established roles in acute coronary syndromes. The GP IIb/IIIa inhibitors are the most recent addition to the pharmacologic armamentarium; their role is evolving rapidly as research on this frontier continues. Table 2 reviews recommended dosing of selected agents in acute coronary syndromes.

Adrenergic beta-Antagonists↗

PubMed2001

Atrioventricular dissociation.

Atrioventricular (AV) dissociation is an electrocardiographic syndrome; a descriptive term for a variety of conditions of abnormal cardiac conduction which all feature independent function of the atria and ventricles. AV dissociation can be subclassified as AV dissociation by default (an independent ventricular pacemaker responds to slowing of the dominant atrial pacemaker) versus AV dissociation by usurpation (acceleration of a latent pacemaker takes control of cardiac conduction by exceeding the intrinsic atrial rate). Inclusion of third degree AV block (complete heart block) as a manifestation of AV dissociation is controversial, yet is functionally appealing in that this disorder also features independent activity of the atria and ventricles.

Aged↗

PubMed2001

Oral agents for the treatment of type 2 diabetes mellitus: pharmacology, toxicity, and treatment.

Currently available oral agents for the treatment of type 2 diabetes mellitus include a variety of compounds from 5 different pharmacologic classes with differing mechanisms of action, adverse effect profiles, and toxicities. The oral antidiabetic drugs can be classified as either hypoglycemic agents (sulfonylureas and benzoic acid derivatives) or antihyperglycemic agents (biguanides, alpha-glucosidase inhibitors, and thiazolidinediones). In this review, a brief discussion of the pharmacology of these agents is followed by an examination of the adverse effects, drug-drug interactions, and toxicities. Finally, treatment of sulfonylurea-induced hypoglycemia is described, including general supportive care and the management of pediatric sulfonylurea ingestions. The adjunctive roles of glucagon, diazoxide, and octreotide for refractory hypoglycemia are also discussed.

Administration, Oral↗

PubMed1999

ECG abnormalities in tricyclic antidepressant ingestion.

The tricyclic antidepressant (TCA) agents are recognized for their potentially lethal cardiovascular and neurological effects in poisoned patients. The 12-lead electrocardiogram (ECG) has emerged as a popular bedside tool in the evaluation of TCA toxicity. Although the history and physical examination play a key role in the assessment of the patient with potential TCA poisoning, the presence or absence of features of the TCA toxidrome are not sufficient to detect or exclude toxicity from this class of drugs. A variety of ECG findings occur with TCA toxicity. Aside from the sinus tachycardia due principally to anticholinergic effects, TCA-toxic changes seen on the ECG are attributable primarily to the sodium channel blockade caused by these agents. The majority of patients at significant risk for developing cardiac or neurological toxicity will have a QRS complex greater than 0.10 seconds or a rightward shift of the terminal 40 ms of the frontal plane QRS complex vector. The majority of these patients will also display these changes early in their emergency department stay. However, the appearance of these findings, either alone or in combination, does not mean the patient will develop significant cardiac or neurological toxicity. The ECG can neither unequivocally rule in nor rule out impending toxicity; recognizing these limitations, the emergency physician can use this bedside tool in combination with other clinical data during the assessment of the poisoned patient.

Adolescent↗

PubMed1998

Evaluation and management of bradyarrhythmias in the emergency department.

Bradyarrhythmias may be due to varied causes, although acute myocardial infarction, hypoxia, sepsis, and hypothermia should be considered. Emergency department therapy consists of treatment of the underlying cause, pharmacologic interventions, and temporary pacing. This article provides a detailed discussion of the causes and treatment of bradyarrhythmias in the emergency department.

Bradycardia↗

PubMed1996

Poisoning from "Spanish fly" (cantharidin).

Cantharidin, known popularly as Spanish fly, has been used for millennia as a sexual stimulant. The chemical is derived from blister beetles and is notable for its vesicant properties. While most commonly available preparations of Spanish fly contain cantharidin in negligible amounts, if at all, the chemical is available illicitly in concentrations capable of causing severe toxicity. Symptoms of cantharidin poisoning include burning of the mouth, dysphagia, nausea, hematemesis, gross hematuria, and dysuria. Mucosal erosion and hemorrhage is seen in the upper gastrointestinal (GI) tract. Renal dysfunction is common and related to acute tubular necrosis and glomerular destruction. Priapism, seizures, and cardiac abnormalities are less commonly seen. We report four cases of cantharidin poisoning presenting to our emergency department with complaints of dysuria and dark urine. Three patients had abdominal pain, one had flank pain, and the one woman had vaginal bleeding. Three had hematuria and two had occult rectal bleeding. Low-grade disseminated intravascular coagulation, not previously associated with cantharidin poisoning, was noted in two patients. Management of cantharidin poisoning is supportive. Given the widespread availability of Spanish fly, its reputation as an aphrodisiac, and the fact that ingestion is frequently unwitting, cantharidin poisoning may be a more common cause of morbidity than is generally recognized. Cantharidin poisoning should be suspected in any patient presenting with unexplained hematuria or with GI hemorrhage associated with diffuse injury of the upper GI tract.

Adolescent↗

PubMedDate not supplied

Tuberculous psoas abscess.

Although its historical significance is well established, Mycobacterium tuberculosis today is considered an extremely rare cause of psoas abscess. Nontuberculous bacterial infection, most commonly secondary to an intraabdominal process but at times appearing without an identifiable source, is responsible for the vast majority of psoas abscesses. The recent resurgence of tuberculosis may portend another change in the etiologic trend of psoas abscess. It is essential that the emergency physician not only recognize the potentially subtle presentation of psoas abscess, but also include tuberculosis in the differential diagnosis of infectious causes of this entity. A case of tuberculous psoas abscess in an HIV-negative man is presented. A review of the anatomy, pathophysiology, clinical presentation, epidemiology, and treatment follows, highlighting the similarities and differences between tuberculous and nontuberculous psoas infection.

Antitubercular Agents↗

PubMedDate not supplied

Postexposure rabies prophylaxis in an urban emergency department.

The purpose of this retrospective study was to identify those patients presenting to an urban emergency department with animal-related wounds, define source animal demographics, and assess adequacy of wound care, rabies immunoprophylaxis, and follow-up. Sixty-three patients comprised the study population; dogs (76%) and cats (16%) were the principal source animals. Postexposure rabies prophylaxis was indicated in ten patients (16%) due to wounds inflicted by stray dogs and cats. Animal behavior and vaccination history were inconsistently addressed, but were documented significantly more often in patients who received prophylaxis. Inclusion of soap in wound care was not significantly more common in the treated group. Human rabies immune globulin was administered incorrectly at least one-third of the time. Appropriate follow-up was arranged in only 31% of cases; this occurred significantly more often with treated patients. An awareness of both regional epidemiological trends in animal rabies and local health department treatment recommendations will encourage optimal delivery of postexposure treatment in cases of potential rabies exposure.

Adolescent↗