UMEM Educational Pearls

Title: Tricyclic Antidepressants (TCA)

Keywords: tricyclic antidepressant, electrocardiogram, cardiac toxicity (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Tricyclic Antidepressants (TCA) - Lack of terminal 40msec R wave (R wave in AvR, S wave in I, AvL) means the patient is NOT TCA toxic. - 40msec R wave + QRS >100msec = possible TCA toxicity, treat with NaHCO3 and recheck ECG. - TCA toxicity defined by ECG; if QRS > 100msec, 33% seizures; if QRS > 160msec, 50% v tach Boehnert MT, Lovejoy FH Jr. Value of the QRS duration versus the serum drug level in predicting seizures and ventricular arrhythmias after an acute overdose of tricyclic antidepressants. N Engl J Med. 1985 Aug 22;313(8):474-9.

Title: GI Bleed and Myocardial Ischemia

Category: Cardiology

Keywords: GI Bleed, Myocardial Ischemia, ECG (PubMed Search)

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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GI Bleed and Myocardial Ischemia Myocardial ischemia or infarction occurs in up to 20% of patients with significant UGI bleeds. For reasons that are uncertain, the majority of these patients have "silent" MIs (i.e. no pain). It's also unclear whether these patients develop MI purely because of hypoperfusion or because the stress causes a plaque to rupture and thrombose. Whenever you have a patient with a massive UGIB, get an ECG early, regardless of whether or not the patient is having chest pain, and if it's concerning, get cardiology involved early as well. anecdote--I've seen 2 patients with STEMI in the presence of an UGIB, one at Mercy and one at UMMS; neither had chest pain; both got transfused, seen by GI, and went cath within several hours; the takeaway--get both consultants involved EARLY!

Title: Ventricular dysrhythmias in pregnanc

Category: Cardiology

Keywords: Dysrhythmia, Pregnancy, Treatment, Procainamide (PubMed Search)

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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Ventricular dysrhythmias in pregnancy Amiodarone should be considered a last choice in pregnancy. It is the only class D antiarrhythmic, and even short infusions can be associated with fetal hypothyroidism, IUGR, fetal bradycardia, and prematurity. Lidocaine or procainamide are preferred. Also, cardioversion/defibrillation/pacing is considered safe in any stage of pregnancy.

Title: Non-ACS causes of elevation troponins

Category: Cardiology

Keywords: Troponin, cause, Non-ACS (PubMed Search)

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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Non-ACS causes of elevation troponins: 1. acute PE 2. Stanford A aortic dissections 3. acute heart failure 4. strenuous exercise (e.g ultra-endurance activities) 5. cardiac toxins 6. ablation therapy/cardiversion 7. cardiac infiltrative diseases 8. post-heart transplant (may persist up to 3 mos) 9. cardiac contusion 10. sepsis 11. rhabdomyolysis

Title: AMI versus Aneurysm

Category: Cardiology

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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AMI versus Aneurysm For ECG distinction between AMI versus ventricular aneurysm, look for reciprocal changes and height of T-waves: 1. Reciprocal ST depression strongly favors AMI. 2. Large T-waves in leads with Q waves and STE is likely AMI. Ventricular aneurysm usually gives you "blunted" or flat T-waves in those leads.

Title: Dyspnea

Category: Cardiology

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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Elderly are more likely to present with dyspnea (49% [the most common anginal equivalent]), diaphoresis (26%), nausea and vomiting (24%), and syncope (19%) as a primary complaint. The takeaway point: always get that ECG early in elderly patients with these complaints, even when CP is absent!

Title: Syncope

Category: Cardiology

Keywords: Syncope, CHESS, San Francisco (PubMed Search)

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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Syncope Patients with syncope that are considered to be relatively low risk for complications clinically (i.e. those patients that are not clear-cut admissions) should be evaluated for the 5 CHESS criteria (from the San Francisco Syncope Rules). If they meet none of those criteria, then they are considered to be at very low risk for short-term adverse outcomes and they can be discharged for outpatient follow-up. If they do have any CHESS criteria, they are considered to be at higher risk and admission should be strongly considered. CHESS criteria: history of CHF, hematocrit < 30, ECG abnormalities, shortness of breath, presenting systolic pressure < 90.

Title: Cardiac Output After Age 35

Category: Cardiology

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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After the age 35, cardiac output decreases by approximately 1% per year. That means that elderly patients are at much higher risk for CHF, especially when they are stressed in some way. CHF can develop in the elderly as a result of any stype of infection or other non-cardiac insult. If decompensated CHF is diagnosed in an elderly patient, don't forget to evaluate the patient carefully for potential non-cardiac causes.

Title: Acute Pericarditis

Category: Cardiology

Keywords: Pericariditis, TB, Viral (PubMed Search)

Posted: 7/14/2007 by Amal Mattu, MD (Updated: 2/8/2026)
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Acute Pericarditis Viral and idiopathic causes account for 80-90% of cases of acute pericarditis (AP) in immunocompetent patients from developed countries. Therefore empiric treatment and extensive search for an underlying cause is unnecessary in the majority of cases we see. However, the etiology of AP in developing countries is very different, with TB-related AP predominating. 70-80% of cases from Sub-Saharan Africa and more than 90% of HIV-related cases of AP are tuberculous. Therefore, in the U.S. tuberculous pericarditis should be strongly considered among immigrants/visitors from developing countries and among patients with HIV.

Title: Urine Drug Screens

Category: Toxicology

Keywords: drug abuse, urine drug screen, cocaine (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Urine Drug Screens Though we order them often, be sure you know what your results mean: Cannabinoids: an accurate test though clinically not important information, positive for 5 days to a full month with chronic users. Cocaine: the most accurate and precise test, positive for 3-5 days. Amphetamine: the most imprecise with many false positives and false negatives. Cough/cold preparations that contain pseudephedrine, phenylephrine or other decongestants can turn it falsely positive. BDZ: only benzodiazepines that are metabolized to oxazepam will turn positive. You can see false negatives with alprazolam and even lorazepam. Opioids: Semisynthetics like oxycodone and hydrocodone may give false negatives at low levels. This screen will NOT catch methadone, meperidine, fentanyl, propoxyphene, tramadol. PCP: False positives from dextromethorphan and ketamine

Title: Heavy Metal Poisoning Clues for Diagnosis

Category: Toxicology

Keywords: metal, poisoning, thallium (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Heavy Metal Poisoning Clues for Diagnosis Mees lines, indication of arrested nail growth, occurs in lead, arsenic and others Most heavy metals will cause a proteinuria Microcytic anemia and basophilic stippling seen in lead, arsenic, mercury Peripheral neuropathies in otherwise healthy person Thallium causes classic painful paresthesias in lower extremities

Title: Digoxin Toxicity

Category: Toxicology

Keywords: digoxin, cardiac glycoside, toxicity (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Digoxin Toxicity Most common finding on ECG when digoxin toxic: PVCs Most classic ECG in digoxin toxicity: PAT with block Pathognomonic finding (RARE): Bidirectional ventricular tachycardia Easy formula for administration of digoxin specific Fab (Digibind?? or DigiFab?). Remember to round up even if its 2.3 vials, give 3. [(Dig Serum Concentration(ng/mL)) x wt(kg)] / 100 = # vials

Title: Lithium Toxicity Management

Category: Toxicology

Keywords: lithium, renal failure, neurologic (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Lithium Toxicity Management Initial Therapy: 2x maintenance fluid with normal saline Hemodialysis is controversial but will remove lithium quickly Association of permanent neurologic sequelae with elevated lithium level(1) o Looks like a cerebellar stroke 1- Adityanjee. The syndrome of irreversible lithium-effectuated neurotoxicity (SILENT). Pharmacopsychiatry. 1989 Mar;22(2):81-3.

Title: Hyperthermia

Category: Toxicology

Keywords: hyperthermia, serotonin syndrome, neuroleptic malignant syndrome (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Hyperthermia Neuroleptic Malignant Syndrome (Dopamine Inhibition): treat with bromocriptine Serotonin Syndrome (5-HT1A agonism): treat with serotonin antagonist Malignant Hyperthermia (Genetic): treat with dantrolene

Title: Diagnosing Salicylate Toxicity

Category: Toxicology

Keywords: Salicylate, aspirin, ferric chloride (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Diagnosing Salicylate Toxicity - Acute ingestion can initiially present with nausea, vomiting and a respiratory alkalosis - Toxicity defined by an anion gap metabolic acidosis with ketosis and normal glucose - Ferric chloride test (can get from chemistry set): couple of drops into urine, if it changes color to deep purple sensitive positive for presence of salicylate (sensitive but not specific)

Title: Botulinum Toxin

Category: Toxicology

Keywords: botulinum toxin, paralysis, heroin (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Botulinum Toxin Most potent toxin on the planet where 7 picograms IV are lethal to a human Characterized by a descending flaccid paralysis w/o fever bulbar findings 1st Weapon of Mass Destruction but also seen in the IVDA Heroin population Black Tar Heroin outbreak with necrotic ulcers that produced C. botulinum o Most recently in Washington DC 2003 Centers for Disease Control and Prevention (CDC). Wound botulism among black tar heroin users--Washington, 2003. MMWR Morb Mortal Wkly Rep. 2003;52(37):885-6.

Title: Acetaminophen Toxicity

Category: Toxicology

Keywords: acetaminophen, hepatic failure, hepatitis (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Acetaminophen Toxicity Hepatoxicity defined by AST >1000 King s College Criteria to prognosticate hepatic failure and need for transplant: o pH <7.3 o Creatinine >3.4 mg/dL o INR >6.5 o Hepatic encephalopathy Grade III or IV Low phosphate (<1.2 mmol/L) may be predictor of survival and elevated may be indicator of impending hepatic failure. (Especially 48 96 hrs post-ingestion) o Theory is phosphate used in regeneration/healing liver Gow PJ, Sood S, Angus PW. Serum phosphate as a predictor of outcome in acetaminophen-induced fulminant hepatic failure. Hepatology. 2003; 37(3):711.

Title: Toxic Alcohols

Category: Toxicology

Keywords: Ethylene glycol, methanol, toxic alcohol (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Toxic Alcohols Unexplained anion gap metabolic acidosis => give fomepizole (antidote) Hypokalemia, hypocalcemia, elevated creatinine => think ethlylene glycol Visual disturbances => think methanol Ketosis without acidosis and high osmol gap => think isopropanol If osmol gap is >70; high specificity for a toxic alcohol ingestion

Title: Hydrofluoric Acid (HF)

Category: Toxicology

Keywords: hydrofluoric acid, hypocalcemia, burn (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Hydrofluoric Acid (HF) Used in glass etching, brick/porcelain cleaning and available in hardware stores Death has been reported after JUST 2-3% body surface area exposure! Systemic toxicity: hypocalcemia, hyperkalemia and hypomagensemia Local effects: paucity of skin findings with tremendous pain Treatment: skin decontamination, correct electrolyte abnormalities and topical calcium gel for local pain Mayer TG, GrossPI. Fatal systemic fluoride due to hydrofluoric acid burns. Ann Emerg Med 1985; 14: 149-153.

Title: Cyanide

Category: Toxicology

Keywords: cyanide, poisoning, hydroxycobalamin (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto (Updated: 2/8/2026)
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Cyanide Presents with arterialization of venous blood (venous blood draw looks like ABG) Reason: o Hemoglobin is not able to offload oxygen o CN poisons cytochrome c oxidase preventing conversion of oxygen to water and thus production of ATP Old antidote: sodium thiosulfate New antidote: hydroxycobalamin binds CN producing cyanocobalamin (Vit B12) When you give it expects a dip in pulse because of its blue color. Remember CN will give you a beautiful 100% pulse all the way to death. Lee J, et al. Potential interference by hydroxocobalamin on cooximetry hemoglobin measurements during cyanide and smoke inhalation treatments. Ann Emerg Med. 2007 Jun;49(6):802-5. Epub 2007 Jan 8.