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Core EM - Emergency Medicine Podcast

Core EM - Emergency Medicine Podcast

著者： Core EM
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Core EM Emergency Medicine PodcastCore EM 衛生・健康的な生活 身体的病い・疾患
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  • Episode 224: Kidney Stones

    Episode 224: Kidney Stones
    2026/06/08
    A guide to diagnosing, imaging, and managing acute renal colic and nephrolithiasis in the ED. Hosts: Brian Gilberti, MD Avir Mitra, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/Nephrolithiasis.mp3 Download Leave a Comment Tags: Kidney Stones, Urology Show Notes 1. CLINICAL CORE & PHYSIOLOGIC FRAMEWORK Epidemiologic Risk Profiles Lifetime incidence parameters hover around 1 in 11, presenting with a prominent male sex skew.Peak demographic manifestation concentrated within the 30–60 age band.High-yield temporal parameter: 50% recurrence vector within a 5-year post-initial-insult window. Mineralogical Composition Vectors Calcium oxalate crystals represent the predominant structural matrix.Struvite configurations (magnesium ammonium phosphate matrix) account for 1–2% of cohorts.Struvite stones function explicitly as infection-driven configurations secondary to upper tract proliferation; higher distribution index noted in female cohorts. Etiological & Modifiable Relational Dynamics Profound systemic dehydration or low baseline fluid throughput states.High-sodium diet structures and heavy animal-protein consumption loads.Positive genetic/familial history variables.Relative risk modulation: Each variable independently operates to expand baseline risk by a factor of 2x to 3x. Pathophysiologic Symptom Complexes Acute, sudden-onset, maximum-intensity (10/10) unilateral flank pain.Classic structural radiation vector tracking downward toward the ipsilateral groin/genitourinary dermatomes.Distinctive behavioral marker: Renal colic pacing/writhing behavior with zero antalgic position availability.Concomitant autonomic triggers: Nausea and emesis manifest in 50% of acute presentations. Physical Exam Discordance Metrics Severe subjective distress contrasted with a characteristically soft, completely non-tender abdominal palpation exam.CVA tenderness is completely variable and lacks reliable negative predictive value.Atypical Presentation ClassificationsVague, poorly localized abdominal pain presentations occurring in up to 20% of active cases.Isolated lower urinary tract irritative signs including acute frequency or severe urgency. Incidental & Asymptomatic Dynamics Silent intrarenal or ureteral stones found incidentally.Longitudinal tracking demonstrates up to 33.3% of initially asymptomatic cohorts convert to fully symptomatic renal colic within a multi-year tracking window. 2. EXCLUSION DIAGNOSES & CRITICAL PATHWAY RED FLAGS Vascular Mimics: AAA rupture/expansion. This is a mandatory exclusion pathway in elderly cohorts presenting with acute flank or back pain. Physical tracking requires active exploration for an expansile, pulsatile abdominal mass.Gynecologic Emergencies: Ruptured ectopic pregnancy. Demands universal screening protocols via rapid beta-hCG testing in all female patients of childbearing potential presenting with lower abdominal/pelvic localization.Infectious Upper Tract Decompensation: Acute uncomplicated pyelonephritis. Differentiated via persistent high spikes, high fevers, systemic shaking chills, and profound pyuria.Genitourinary Structural Crises: Acute testicular torsion. Mandates a thorough, explicit scrotal/testicular structural exam if the flank pain radiates into the scrotum.Gastrointestinal and Adnexal Torsional Confounds: Acute appendicitis variants, acute mesenteric/bowel ischemia, and ovarian torsion syndromes. 3. LABORATORY TESTING & PHYSIOLOGIC EVALUATION Urinalysis Interpretation Nuances Microscopic or gross hematuria presents in approximately 66% to 90% of acute cases.Critical Pathological Caveat: Complete absence of hematuria documented in 20% to 33.3% of confirmed, acute obstructing ureteral stones.Diagnostic rule: A pristine urinalysis with zero red blood cells is entirely insufficient to exclude acute ureterolithiasis. Urinary pH as a Composition Clue Consistently low urinary pH parameters (pH < 5.5) point strongly toward a uric acid crystalline composition.Elevated urinary pH parameters (pH > 7.5) indicate the presence of urease-producing microbial pathogens, pointing toward a struvite infection stone. Infectious Screening Metrics Active tracking for marked pyuria, positive leukocyte esterase, and bacterial nitrites to rule out an obstructed, infected upper urinary tract system. BMP Immediate quantification of baseline serum creatinine to establish accurate eGFR values.Targeting detection of post-renal AKI from bilateral obstruction, unilateral obstruction in a single functioning kidney, or severe volume depletion. CBC Evaluation for marked leukocytosis.Physiologic Nuance: Mild-to-moderate white blood cell count elevations frequently represent non-specific stress demargination driven by severe pain and repetitive vomiting.High-grade white blood cell shifts demand immediate exclusion of systemic bacteremia or an infected, obstructed urinary system. Adjunctive Lab Pathways Rapid qualitative urine hCG testing.Reflex urine ...
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  • Episode 223: Thyroid Storm

    Episode 223: Thyroid Storm
    2026/05/15
    Diagnosis, workup, and the four-step treatment protocol for thyroid storm. Hosts: Annaliese Elam, MD Brian Gilberti, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/Thyroid_Storm.mp3 Download Leave a Comment Tags: Critica Care, Endocrine, Thyroid Storm Show Notes I. Pathophysiology & Diagnosis Definition: Life-threatening hypermetabolic state resulting from decompensated thyrotoxicosis. Hormonal Profile: Absolute levels of total T₄/T₃ often mirror uncomplicated thyrotoxicosis; storm is driven by rapid rate of rise, increased catecholamine sensitivity, or increased free T₄/T₃ concentrations. Clinical Presentation: Hyperpyrexia (e.g., 104.2°F)Tachycardia/Arrhythmias (e.g., 155 bpm)Altered Mentation: Agitation, delirium, or psychosis; often the primary differentiator between “storm” and “compensated” hyperthyroidismWarm, moist skin Precipitating Events: Infection, trauma, or surgeryParturitionAbrupt cessation of antithyroid medications Burch-Wartofsky Point Scale (BWPS): ≥ 45: Highly suggestive of Thyroid Storm25–44: Suggestive of impending storm< 25: Storm unlikelyNote: High sensitivity but low specificity; can be skewed by unrelated febrile illness. II. Laboratory & Ancillary Findings Thyroid Panel: Characteristically low TSH with elevated free T₄ and T₃. Metabolic Abnormalities: Mild hyperglycemia (catecholamine-induced insulin inhibition)Mild hypercalcemiaElevated LFTs and leukocytosis Cardiovascular: EKG may show sinus tachycardia or atrial fibrillation with rapid ventricular response. III. Management: The Four-Step Blocking Strategy Step 1: Sympathetic Blockade (Beta Blockers) Agent of Choice: PropranololMechanism: Non-selective blockade; in high doses, inhibits peripheral conversion of T₄ to T₃.Dosing: PO: 60–80 mg every 4–6 hoursIV: 0.5–1 mg over 10 minutes Critical Pitfall: Avoid in patients with acute decompensated heart failure with systolic dysfunction; risk of cardiovascular collapse. Step 2: Inhibition of Hormone Synthesis (Thionamides) Agent of Choice: Propylthiouracil (PTU) preferred over Methimazole in life-threatening storm.Mechanism: Blocks synthesis of new hormone and inhibits peripheral T₄-to-T₃ conversion (decreases T₃ by ~45% in 24 hours).Dosing: 200–250 mg PO every 4 hours Step 3: Inhibition of Hormone Release (Iodine) Agents: Potassium iodide (SSKI) or Lugol’s solutionCritical Timing: Must wait at least 60 minutes AFTER thionamide administration.Rationale: Immediate iodine administration provides substrate for new hormone synthesis (Wolff-Chaikoff effect bypass), potentially worsening thyrotoxicosis. Step 4: Inhibition of Peripheral Conversion & Adrenal Support Agent: Glucocorticoids (Hydrocortisone)Mechanism: Inhibits peripheral T₄ to T₃ conversion and treats potential relative adrenal insufficiency.Dosing: 300 mg IV loading dose, followed by 100 mg IV every 8 hours IV. Supportive Care & Avoidance Measures Hyperpyrexia Management: Acetaminophen is the standard of careAvoid Aspirin: Salicylates displace thyroid hormone from thyroid-binding globulin (TBG), increasing free T₄/T₃ levels Volume Resuscitation: Aggressive IV fluids; patients are often profoundly dehydratedMay require 3–5 liters of isotonic crystalloid per 24 hours Take Home Points I. Diagnostic Essentials Clinical Diagnosis: Based on hyperpyrexia, cardiovascular dysfunction, and altered mentation.Key Differentiator: Altered mentation (agitation, delirium, psychosis) is often the sole finding distinguishing “storm” from “compensated” thyrotoxicosis.Burch-Wartofsky Point Scale (BWPS): ≥ 45: Highly suggestive of storm.25–44: Suggests impending storm.< 25: Storm unlikely.Note: High sensitivity, low specificity (e.g., hyperthyroid + flu can score > 45). Triggers: Infection, trauma, parturition, or abrupt cessation of antithyroid drugs. II. The Four-Step Blocking Strategy Beta Blockade (Propranolol): Dose: 60–80 mg PO q4–6h or 0.5–1 mg IV over 10 min.Action: Blocks symptoms and inhibits peripheral T4 to T3 conversion.Caution: Avoid in acute decompensated heart failure with systolic dysfunction. Thionamides (PTU): Dose: 200 to 250 mg every four hours. (note: some resources suggest a loading dose beforehand)Action: Preferred over methimazole; blocks new hormone synthesis and peripheral T4 to T3 conversion. Iodine (SSKI/Lugol’s): Timing: Must wait ≥ 60 minutes AFTER thionamide dose.Action: Blocks hormone release.Pitfall: Early iodine provides substrate for new hormone synthesis, worsening the condition. Glucocorticoids (Hydrocortisone): Dose: 300 mg IV load, then 100 mg IV q8h.Action: Blocks conversion and provides adrenal support. III. Critical Supportive Care Hyperpyrexia: Use Acetaminophen. NEVER Use Aspirin: Displaces thyroid hormone from binding proteins, acutely increasing free T4/T3 levels. Volume: Aggressive fluid resuscitation; patients may require 3–5 L/day due to profound dehydration. Read More
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  • Episode 222: Local Anesthetic Systemic Toxicity (LAST)

    Episode 222: Local Anesthetic Systemic Toxicity (LAST)
    2026/04/07
    We discuss this ominous complication of providing local anesthesia. Hosts: Elaine Jonas, MD Brian Gilberti, MD https://media.blubrry.com/coreem/content.blubrry.com/coreem/LAST.mp3 Download Leave a Comment Tags: Critical Care, Toxicology Show Notes I. Pathophysiology & Mechanisms Definition: Systemic toxicity secondary to local anesthetic (LA) via accidental intravascular injection or excessive systemic absorption. Threshold: Occurs when plasma concentration exceeds the safety threshold for cardiac and neural tissue. Agent Profile: Bupivacaine (High Risk) Highly lipophilic with high protein binding. “Fast-on, Slow-off” Kinetics: Strong Na+ channel binding with extremely slow dissociation during diastole. Myocardial Depression: Direct inhibition of Ca2+ release from the sarcoplasmic reticulum, impairing contractility. Low CC:CNS Ratio: The dose required for cardiac collapse is very close to the dose that triggers seizures (narrow safety margin). Contributing Factors: Acidosis/Hypercapnia: Increases the fraction of free drug and promotes ion trapping in the brain/heart; shifts the LA-binding curve toward higher toxicity. Hypoxemia: Exacerbates myocardial depression and lowers seizure threshold. II. Risk Assessment & Prevention Patient-Specific Risk Factors Extremes of Age: Neonates (low α-1-acid glycoprotein) and elderly (reduced clearance). Body Composition: Low muscle mass/frailty (decreased volume of distribution). Organ Dysfunction: Hepatic: Reduced metabolism of amide LAs. Renal: Accumulation of metabolites; risk of metabolic acidosis lowering seizure threshold. Cardiac: Reduced cardiac output slows hepatic delivery/clearance; heart failure patients are more sensitive to Na+ channel blockade. Pregnancy: Increased sensitivity to cardiotoxicity. Procedural Risk Factors Vascularity of Site (Highest to Lowest Risk): Intercostal blocks (highest absorption rate). Caudal/Epidural. Interfascial plane blocks (e.g., TAP block). Psoas compartment/Sciatic. Brachial plexus. Technique: Large volume infiltration, lack of ultrasound, lack of incremental injection. Prevention Mandates Weight-Based Dosing: Lidocaine (Plain): Max 4.5 mg/kg. Lidocaine (with Epi): Max 7 mg/kg. Bupivacaine: Max 2.5–3 mg/kg. Incremental Injection: 3–5 mL aliquots with frequent aspiration. Intravascular Marker: Use Epinephrine (1:200,000) to detect accidental IV placement (HR increase >10 bpmor SBP increase >15 mmHg). III. Clinical Presentation Neurologic Phase (Early to Late) Subjective: Metallic taste, tinnitus, circumoral numbness/tingling. Objective: Visual disturbances, agitation, confusion, tremors. Critical: Generalized tonic-clonic seizures, rapid progression to CNS depression, coma, and apnea. Note: Early phases are often masked in patients receiving midazolam or propofol. Cardiovascular Phase Initial: Hypertension and tachycardia (if epi used) or transient stimulatory phase. Conduction Defects: PR prolongation, QRS widening (classic sign), bundle branch blocks. Dysrhythmias: Bradycardia (most common), VT/VF, PEA, asystole. Contractility: Profound, refractory hypotension and cardiogenic shock. IV. Immediate Management Algorithm Goal: Prevent hypoxia/acidosis and sequester the toxin. 1. Initial Actions Stop Injection: Immediately halt all LA administration. Call for Help: Specify “LAST Protocol” and “Intralipid Kit.” Airway Management: 100% O2​. Hyperventilate slightly if needed to counter respiratory acidosis. Low threshold for intubation (hypoxia/acidosis rapidly worsen LAST). 2. Seizure Control First-line: Benzodiazepines (e.g., Midazolam). Avoid: Propofol if hemodynamically unstable (exacerbates cardiac depression). Neuromuscular Blockers: May be needed for ventilation, but remember they do not stop CNS seizure activity. 3. Lipid Emulsion Therapy 20% Indications: Start at first sign of serious toxicity (airway compromise, seizures, or CV instability). Bolus: 1.5 mL/kg IV over 1 minute. Infusion: 0.25 mL/kg/min immediately following bolus. If Instability Persists: Repeat bolus (up to 2 times). Increase infusion to 0.5 mL/kg/min. Upper Limit: ≈12 mL/kg total dose. 4. Modified ACLS Epinephrine: Use low doses (<1 mcg/kg) to avoid worsening arrhythmias and interfering with lipid rescue. Antiarrhythmics: Amiodarone is preferred. CONTRAINDICATED: Lidocaine: (Class Ib antiarrhythmic—will worsen toxicity). Vasopressin: Associated with poor outcomes in animal LAST models. Calcium Channel Blockers / Beta Blockers: Exacerbate myocardial depression. Refractory Arrest: Early consultation for ECMO or Cardiopulmonary Bypass (CPB). V. Differential Diagnosis for the Peri-Procedural Patient High Spinal: Ascending sensory/motor block, profound sympathectomy (hypotension/bradycardia). Anaphylaxis: Urticaria, wheezing (rare with amides, more common with esters). Air/Gas Embolism: Sudden dyspnea, “mill-wheel”...
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