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![Malignant Hyperthermia
Reaction to certain classes of drugs
including inhaled anesthetics
(halothane and others) and
depolarizing neuromuscular blockers
(succinylcholine and decamethonium
[syncurine])
Markedly increased intracellular
calcium increased cellular
metabolism sustained muscle
tetany
Susceptibility to malignant
hyperthermia is inherited](https://image.slidesharecdn.com/board-review-130723190137-phpapp01/75/Board-Review-31-2048.jpg)
![Hypothermic emergencies
Core T below 35 (95 F)
Exposure to cold weather and submersion in
cold water
Causes cellular dysfunction and lyte
abnormalities, esp. hyperkalemia
Mild hypothermia [32-35 C (89.6-95 F)]
shivering, AMS, ataxia, polyuria
Moderate hypothermia [28-32 C (82.4-89.6 F)
decreased HR, CO, more severe AMS,
cardiac arrhythmias
Severe hypertormia [<28 C (82.4)]
pulmonary edema, coma, hypotension,
areflexia, ventricular arrhythmias and cardiac
arrest](https://image.slidesharecdn.com/board-review-130723190137-phpapp01/75/Board-Review-35-2048.jpg)
More Related Content
Board Review
- 1. Board Review Shock Emergent Disordersin Critical Care Bita Fakhri, MD, MPH Internal Medicine Residency Program Boston University Medical Center
- 2. Shock Decreased tissueperfusion inadequate O2 delivery tiessue ischemiaCommon Clinical Features of Shock 1. HYPOTENSION SBP < 90 mm Hg MAP <60 mm Hg Acute decreased in SBP of > 40 mm Hg Lack of MAP response to initial fluid challenge 2. END_ORGAN DYSFUNCTION DUE TO HYPOPERFUSION Decreased urine output Change in mental status Increased serum lactic acid level
- 3. Key Hemodynamic Parametersof Shock Ohm’s Law: V=RI CO = SVR x BP
- 4. Blood Pressure Cardiac output (decreased incardiogenic shock) Systemic Vascular Resistance (decreased in distributive shock) Heart Rate Stroke Volume Preload (decreased in hypovolemic shock) Contractility Afterload
- 5. Type of ShockDecreased parameter Example Cardiogenic Cardiac output Acute heart failure, massive pulmonary emboli Distributive Systemic vascular resistance Sepsis, anaphylaxis Hypovolemic Preload Acute hemorrhage, severe dehydration
- 6. Agent (dose) Receptors Clinical UseCommon Side Effects or Contraindications Norepinephrin e a1 > B1 First line in septic shock Some arrhythmias, digital ischemia Dopamine (low) DA >B1 Historically used fir kidney failure (no evidence of effectiveness Highest arrhythmia risk and ischemia Dopamine (medium) B1> B2 Septic or cardiogenic shock Dopamine (high) a1 > B1 First line in septic shock Epinephrine (low) B1> B2 Second line for septic or cardiogenic shock Arrhythmias and ischemia Epinephrine (high) a1 = B1 Second line for septic shock phenylephrine a1 Milder shock states, least risky through peripheral IV Lowest arrhythmia risk, not as powerful as other vasopressors Vasopressin Vasopressin Second Splanchnic ischemia, no
- 7. A 71Mis evaluated in the ED for septic shock secondary to a UTI. On P/E, he is lethargic and confused. Vitals: T: 101.3, BP: 80/35, Pulse: 122/min, RR: 23 Right CVA ttp is noted. Labs: hematocrit: 33%, WBC: 15600 UA: innumerable leukocytes and gram negative bacteria. Blood and urine culture results are pending.
- 8. Which ofthe following should be accomplished in the next hour? a) Attain hematocrit greater than 35% b) Begin low-dose dopamin c) Initiate antibiotic therapy d) Insert a pulmonary artery catheter
- 9. Empiric antibiotictherapy should be initiated whithin 1 hour of recognition of sepsis after cultures have been taken from the blood and other suspected sites of infection. (#timetoantibiotic)
- 10. A 41Fis admitted to the ICU for a 1-day hx of progressively worsening AMS and jaundice. Her MHx is significant for autoimmune hepatitis dx’ed 10 yrs ago. On P/E: Vitals: T: 91.4, BP: 105/55, pulse rate: 110/min, RR: 27/min; BMI: 18 She is unresponsive to sternal rub and is jaundiced. The lungs are clear and cardiac examination is normal. Abdominal examination reveals a distended abdomen with a detectable fluid wave. The extremities are WWP. Lab: WBC: 9800, Cr: 1.6, lactic acid level: 6 – UA: unremarkable. Blood and urine culture results are pending. Imaging: CXR: nl IVF and epiricbroad-spectrum antibiotics are begun.
- 11. Which ofthe following is the most appropriate next step in management? a) Abdominal CT b) Diagnostic paracentesis c) Dopamine d) Hydrocortisone
- 12. The primarygoals of sepsis management are infection source control and early antibiotics
- 13. A 78Fis treated in the ICU for a 24-hr hx of AMSthat has been progressively worsening. She is a resident of a nursing home, and her MHx is significant for Alzheimer disease. On arrival to the ED, she was disoriented, febrile, tachycardic with a HR of 115/min, and hypotensive with a BP of 82/40. Labs: WBC: 33,000 – hemoglobin: 11 – urine dipstick was positive for nitrites and leukocyte esterase. – Blood and urine culture results are pending. Imaging: CXR: normal Central access was obtained and she was started on broad- spectrum antibiotics. A 1000-ml normal saline fluid challenged was administered over 30 minutes. Current examination in the ICU shows the patient to have an unchanged mental status. BP is now: 85/45 mm Hg and HR: 100/min. Her P/E is unchanged
- 14. Which ofthe following is the most appropriate immediate next step in management? a) Erythrocyte transfususion b) Hydrocortisone c) Norepinephrine d) Normal Saline at 200 ml/h
- 15. Vasopressor therapyis indiacted to maintain a MAP of greater than or equal to 65 mm Hg or CVP measurement of 8-12 mm Hg in patients with sepsis who have failed to respond to an initial crystalloid fluid challenge.
- 16. Emergent Disorders inCritical Care Acute Inhalational Injuries Anaphylaxis Hypertensive Emergencies Hyperthermic Emergencies Hypothermic Emergencies Toxicology
- 17. Acute Inhalational Injuries Burn victims Approximately half of deaths associated with with burns are due to complications of inhalational injury When the inhalational exposure is brief and the inhaled toxins are water soluble tissue damage is greates in the proximal airways When inhalational injuries include less water-soluble toxins or prolonged heat exposure damage can extend into distal airways and lung parenchyma
- 18. Complications: pulmonaryedema, airway stenosis, RADS, bronchiolitisobliterans, bronchiectasis and parenchymal fibrosis CO, Cyanide toxicity common in smoke inhalation Burn victims at high risk of secondary infections: staph, pseudomonal
- 19. Supportive Care ofpatients with Acute Inhalational Injuries: IV fluids Intubation for mechanical ventilation Chest physiotherapy Bronchoscopic debridement and suctioning Inhaled racemic epinephrine Antibiotics
- 20.
- 21. Clinical Features of Anaphylaxis Urticaria Tachycardia (sometimes bradycardia) Stridor, hoarseness, wheezing Hypotension GI Sx: cramping abdominal pain, vomiting and diarrhea
- 22. Angioedema A componentof anaphylaxis ACEIs and familial (C1 inhibitor deficiency)
- 23. Management of Anaphylaxis: O2 and IV fluids Epinephrin (SQ or IM) – higher doses or continuous for patients on BBs Antihistamines or coticosteroids (strong evidence is lacking) Inhaled bronchodilators reduce bronchospasm and airway edema Airway support With timely supportive care, anaphylaxis is rarely fatal
- 24. Hypertensive Emergencies Episodesof elevated BP associated with end-organ damage Men, black patients and elderly patients with poorly controlled essential hypertension CNS (presenting with stroke in 25%), renal (AKI), cardiovascular (ischemic chest pain or acute heart failure)
- 25. BP shouldbe measured in both arms and in both supine and standing positions A careful neuro exam including mental status and visual fields and acuity Lab studies: CBC, BMP, cardiac biomarkers, UA, drug levels including cocaine and amphetamines EKG, CXR, brain imaging (AMS, neuro findings suggestive of stroke) Aortic dissection is always a possibility (CT-angio, TEE)
- 26. BP shouldbe lowered by no more than 25% initially Systolic and diastolic targets over the next 2-6 hours: 160/110 with gradual correction after that
- 27. Agent (Class) NotesAdverse Effects Nitroprusside (vasodilator) Easy to titrate; often 1st choice for acute situations Risk for cyanide toxicity NTG (vasodilator) Used for MI; tolerance develop Headache, bradycardia Hydralazine (vasodilator) Safe in pregnancy Nausea, headache and tachycardia Labetolol (alpha and beta blocker) Can be switched to oral Bradycardia, heart block, nausea, bronchospasm Enalaprilat (ACEI) Can be switched to oral; good for LV failure Prolonged hypotension Nicardipine (CCB) Often used for patients with stroke MI, tachycardia, headache Fenoldopam (dopamine agonist) Can be titrated up slowly; may be protective of kidneys Flushing, headache, nausea, tachycardia, possibly increased MI Phentolamine (alpha blocker) Used for dx of and surgery for Nausea, arrhythmia
- 28. Hyperthermic Emergencies Arise in core body temperature > 40 C (104.0 F) Clinical features: AMS (including seizures), muscle rigidity, and rhabdomyolysis (with kidney failure) – severe cases: DIC, ARDS Heat stroke Malignant hyperthermia Neuroleptic malignant syndrome
- 29. Heat Stroke Failureof the body’s thermoregulatory system Impaired thermoregulation: elderly and patients treated for conditions that lead to dehydration and anhidrosis Overwhelmed thermoregulation: athletes and military recruits who are required to exercise strenuously in hot and humid weather
- 30. Patients shouldbe cooled to lower their core body temperature Do not respond to centrally acting antipyretic medications Evaporative cooling methods and ice packs are usually most effective In severe cases, cold gastric or peritoneal lavage may be attempted BZD decrease discomfort and shivering during these treatments
- 31. Malignant Hyperthermia Reactionto certain classes of drugs including inhaled anesthetics (halothane and others) and depolarizing neuromuscular blockers (succinylcholine and decamethonium [syncurine]) Markedly increased intracellular calcium increased cellular metabolism sustained muscle tetany Susceptibility to malignant hyperthermia is inherited
- 32. Severe musclerigidity, masseter spasm, hyperthermia with core T up to 45, cardiac tachyarrhythmias, and rhabdomyolysis are common manifestations. Mortality rate: 10% Triggering agent should be stopped Fluids and cooling methods should be initiated Dantrolene is given q 5-10 min until hyperthermia and rigidity resolve Dantrolene can also prevent recurrence in patients with a hx of malignant hyperthermia if given before administration of the triggering agent
- 33. Neuroleptic Malignant Syndrome Idiosyncraticreaction to neuroleptic antipsychotic agents Characterized by muscle rigidity, hyperthermia and autonomic dysregulation Delirium is common Potent “typical” neuroleptics are most commonly implicated Often occurs after medication is started or uptitrated – it occasionally occurs after years of problem-free use Concomitant Li use may be a risk factor
- 34. Mortality rate:10-20% Treatment include: stopping the neuroleptic agent, maintaining BP stability, IVF, lowering the elevated T, BZD for agitation Dantrolene and bromocriptine are also used, but the evidence for these agents is weak
- 35. Hypothermic emergencies CoreT below 35 (95 F) Exposure to cold weather and submersion in cold water Causes cellular dysfunction and lyte abnormalities, esp. hyperkalemia Mild hypothermia [32-35 C (89.6-95 F)] shivering, AMS, ataxia, polyuria Moderate hypothermia [28-32 C (82.4-89.6 F) decreased HR, CO, more severe AMS, cardiac arrhythmias Severe hypertormia [<28 C (82.4)] pulmonary edema, coma, hypotension, areflexia, ventricular arrhythmias and cardiac arrest
- 36. J Wave (osbornewave) A 47-year-old man with chronic schizophrenia was hospitalized after prolonged hypothermia. The initial electrocardiogram revealed Osborn waves (arrowheads) similar in amplitude to the R waves. Characteristic sinus bradycardia and prolongation of the QRS interval and the corrected QT interval (QTc) were also noted. During rewarming, the Osborn waves diminished in amplitude, and they disappeared after 24 hours. The baseline tremor artifact caused by shivering (arrows) resolved on normalization of the patient's core body temperature. In 1953, Dr. John Osborn described the J wave as an “injury current” resulting in ventricular fibrillation during experimental hypothermia. More recent findings suggest that hypothermia increases the epicardial potassium current relative to the current in the endocardium during ventricular repolarization. This transmural voltage gradient is reflected on the surface electrocardiogram as a prominent J, or Osborn, wave. The differential diagnosis of prominent Osborn waves includes early repolarization, hypercalcemia, and the Brugada syndrome.
- 37. Giant Osborn Wavesin Hypothermia Krantz MJ, Lowery CM. N Engl J Med 2005;352:184-184.
- 38. Toxicology Syndrome Manifestations Representative Drugs SympathomimeticTachycardia Hypertension Diaphoresis Agitation Seizures Mydriasis Cocaine Amphetamine Ephedrine Caffeine Cholinergic “SLUDGE” Confusion Brochorrhea Bradycardia Miosis Organophosphates (insecticides, sarin) Carbamates Physostigmine Edrophonium Nicotine
- 39. Toxicology Syndrome Manifestations Representative Drugs AnticholinergicHyperthermia and dry mucous membranes Agitation, delirium Tachycardia, tachypnea Hypertension Mydriasis Antihistamines TCA Antiparkinson agents Atropine Scopolamine Opioids Miosis Respiratory depression Lethargy, confusion Hypothermia Bradycardia hypotension Morphine and related drugs Heroin
- 40. Alcohols Alcohol Common Name Toxic Metabolite Nontoxic Metabolite Anion Gap Osmolar Gap Toxicity Antidote MethanolWood alcohol Formic acid --- YES YES Retina Fomepizol e, ETOH, Dialysis Ethylene glycol Antifreeze Glycolic, Glyoxolic and oxalic acid --- YES YES Renal Tubules Fomepizol e, ETOH, Dialysis Isopropyl alcohol Rubbing alcohol --- Acetone NO YES CNS Depressio n Fomepizol e, ETOH, Dialysis
- 41. Effect of Fomepizoleon the Pathophysiological Effects of Poisoning from Ethylene Glycol and Methanol. Brent J. N Engl J Med 2009;360:2216-2223.
- 44. Toxicity of Drugsof Abuse Agent Toxic Dose (or serum level) Toxic effect or syndrome Pharmaceuti cal antidote Other interventions Acetaminophen 7.5 g in 8 hrs Acute hepatitis, fulminant hepatic failure NAC PO or IV within 8 hrs (may give later as well) Charcoal within 4 hours BZD variable CNS and respiraory suppression Flumazenil (caution if risk of seizures) Ventilatory and hemodynamic support BB variable Bradycardia, heart block, hypotension Glucagon, CaCl2 Transcutaneous or transvenous pacing CCB variable Bradyarrhythmia ; heart block, hypotension Glucagon, CaCl2 Transcutaneous or transvenous pacing Digoxin Serum levels have poor correlation with toxicity Bradyarrhythmia and tachyarrhythmia; chronic toxicity, CNS and GI Sx Digoxin- specificAb HEMODIALYSI S IS NOT EFFECTIVE
- 45. Toxicity of Drugsof Abuse Agent Toxic Dose Toxic Effect or Syndrome Pharmaceutical Antidote Other Interventions Sulfonylureas One tablet in a child or non- diabetic patient may cause hypoglycemia Hypoglycemia and related Sx Dextrose, Octreotide, glucagon for short term while dextrose is delayed Beware recurrent hypoglycemia even after initial response Lithium Most overdoses are chronic (serum level upper limit is 1.2 mEq/L for acute mania, 0.8 mEq for maintenance; 3 indicates severe toxicity) Tremor, nausea, polyuria, DI, arrhythmias, photosensitivitie s, cardiogenic shock due to CNS effect NO ANTIDOTE FOR Li; medical treatments for secondary arrhythmias, seizures, hypotension Hemodialysis for AMS, anuria or seizures; IV fluid hydration with careful monitoring of lytes, esp in DI Salicylates Levels > 30-40 mg/dL usually mean clinical toxicity; chronic toxicity is more common and more dangerous Metabolic acidosis, hyperventilation, dehydration; severe intoxication can cause seizure, hypoglycemia and lyte abnormalities Sodium bicarbonate infusionto achieve urine output of > 2 mL/kg/h and pH of >8 (pH is more important than diuresis) HD for severe toxicity or poorly tolerated medical therapy
- 46. Agent Toxic Dose(or serum level) Toxic Effect or Syndrome Pharmaceutical Antidote Other Interventions Theophylline Therapeutic range 10- 20mcg/mL, but toxicity can occur in this range Nausea, nervousness, CNS stimulation, HTN, tachypnea, seizures, atrial and ventricular arrhythmias, hypokalemia, hyperglycemia, status epilepticus Activated charcoal can be given Charcoal hemoperfusion is treatment of choice, but HD can also be used if hemoperfusion is not available;cardio version, seizure control, airway management, electrolyte correction TCA Levels do not correlate well with toxicity; better to follow clinical signs and Sx Sudden or delayed onset of seizures, severe arrhythmias, hypotension, rhabdomyolysis, and kidney failure Bicarbonate infusion titrated to QT interval improvement on EKG HD is not effective, monitor and correct lytes, defibrillation, pacing for bradycardia (avoid atropine or cathecholamine s)
- 47. A 55Mis evaluated in the ED after being found unconscious on the ground outside of his home by family members. He was difficult to arouse and was confused. He was breathing spontaneously, but his breaths were rapid and shallow. P/E: Vitals: T: 97.7 BP: 135/91, pulse 110/min, RR: 24/min Other than tachycardia, the cardiopulmonary examination is normal. The abdomen is soft, no focal findings on neuro exam
- 48. Labs: BUN: 14 Cr:1.9 Lytes: Na: 138 K: 4.1 Cl: 90 Bicarb: 12 glucose: 90 Lactic acid: 2.8 Serum osmolality 390 ABG: pH: 7.24 PCO2: 28 PO2: 102 Serum Tox: negative for ETOH, opioids, BZD and common recreational drugs Imaging: CXR: no lung infiltrates or masses. There is very little urine in the bladder, but urine obtained by catheterization contains many erythrocytes and envelope- shaped crystals.
- 49. Which ofthe following is the most appropriate treatment? a) Hemodialysis b) Intravenous ethanol c) Intravenous fomepizole d) Intravenous fomepizole and hemodialysis e) Supportive care
- 50. Calculated serumosm: 2 Na + Glucose/18 + BUN/2.8 = 2 (138) + 90/18 + 14/2.8 = 276 + 5 + 5 = 376 Osmolality gap = observed – expected Osm gap = 390 – 376 = 14
- 51. #classicHACadmission A 39yo M is admitted to the hospital for new-onset agitation, fluctuating level of consciousness and tremors. He is diagnosed with acute alcoholic hepatitis. On P/E, Vitals: T: 101.8, BP: 95/55, HR: 130 and RR: 30 Jaundice is noted. The abdomen is protuberant with ascites, but is soft with no abdominal rigidity or guarding. There’s no blood in stool. The patient is agitated and disoriented, is unable to maintain attention and appear to be having visual hallucination. He believes that the nurse has stolen his wallet (which is in his bedside drawer) in order to obtain his identity. He is diaphoretic and tremulous. Asterixis is absent, and the remainder of neurologic examination is normal.
- 52. Which ofthe following is the most appropriate management? a) Ceftriaxone b) CT of the head c) Haloperidol d) Lactulose enema e) Lorazepam
- 53. Delirium tremensis characterized by fluctuating level of consciousness, disorientation, reduce d attention, global amnesia, impaired cognition and speech and often hallucinations and delusions.
- 54. A 21yo M is evaluated in the ED for shortness of breath after a bee sting. He feels lightheaded and describes a sense of puffiness in his face. On P/E: Vitals: T: 100.4, BP: 98/60, HR: 100 RR: 24/min He is agitated, bilateral wheezing is noted. There is no stridor and no evidence of facial, tongue or oropharyngeal swelling. There’s no rash. CXR shows hyperinflation.
- 55. Which ofthe following is the most appropriate treatment? a) Endotracheal intubation and mechanical ventilation b) Intramuscular epinephrine and inhaled albuterol c) Intravenous diphenhydramine and methylprednisolone d) Intravenous epinephrine, methylprednisolone, and diphenhydramine
- 56. A 19-year-oldwoman is evaluated in the ED after taking an overdose of medication in an apparent suicide attempt. On P/E: she is intubated and on mechanical ventilation. She is obtunded. Vitals: T: 100.2, BP: 96/60, HR: 92, RR on assisted mode of ventilation: 18/min.
- 57. Laboratory studiesreveal a plasma glucose level of 100. Qualitative urine toxicology screen reveals the presence of benzodiazepines and tricyclic antidepressants. No other toxins are identified in her serum or urine. Initial EKG shows sinus tachycardia with a QRS duration of 90 ms. – EKG in the ICU several hours later shows a QRS duration of 130 ms.
- 58. In additionto isotonic saline and vasopressors, which of the following is the most appropriate next step in management? a) Naloxone b) Procainamide c) Saline diuresis d) Sodium bicarbonate infusion
- 59.
- 60. TCA (Na-channel blocker) Toxicity Sinus tachycardia with first-degree AV block (P waves hidden in the T waves, best seen in V1-2). Broad QRS complexes. Positive R’ wave in aVR.
- 61. A 62yoM is evaluated in the ED for headache and confusion. He does not have chest pain or discomfort. His medical hx is significant for essential hypertension, transient ischemic attack, type 2 DM (controlled by diet), and high cholesterol. His current medications are HCTZ, amlodipine, aspirin andatorvastatin.
- 62. On P/E: Vitals:T: normal, BP: 220/135 (same in both arms), HR: 88, RR: 20; BMI: 31. He is intermittently lethargic and agitated, and he’s oriented to self and place but not date and time. Funduscopic exam cannot be performed owing to agitation. There is no focal weakness or loss of sensation, the cranial nerves are intact, and the gait is slow but otherwise normal. The lungs are clear. Pedal edema is noted. Labs: Lytes, CBC, Ti, UA all normal Imaging: CXR: normal CT-head w/o contrast: evidence of old lacunar infarct but no signs of acute stroke or bleeding.
- 63. Which ofthe following is the most appropriate initial target blood pressure for this patient? a) 130/80 mm Hg b) 140/90 mm Hg c) 185/110 mm Hg d) 200/120 mm Hg
- 64. A 50yoM is admitted to the hospital for pneumonia. He was started on antibiotics in the ED. He has a hx of bipolar disorder that is controlled with Li and risperidone. On the eveing of admission, he becomes agitated and confused. He is given IV haloperidol, and he develops fever and muscle rigidity.
- 65. On P/E: Vitals:T: 39.9 (103.8), BP: 187/108, pulse rate: 110/min, RR: 32/min. Diaphoresis, rigidity and agitation are present. No stridor or signs of respiraory failure are noted.
- 66. In additionto IVF therapy, which of the following is the most appropriate initial treatment? a) Acetaminophen b) Atracurium c) Intubation and mechanical ventilation d) Lorazepam e) Nitroprusside
- 67. An 18yo F is evaluated in the ED after being rescued from a burning house. She was unconscious for a few minutes at the scene and on the way to the hospital, but she regained consciousness in the ED. On P/E: she is agitated but follows commands and is oriented Vitals: T: 99.3, BP: 145/80, pulse rate: 20/min, SaO2: 98% on RA She coughs frequently. There are no skin burns. No cyanosis, respiratory stridor, sputum production, or soot around airway orifices is noted.
- 68. Labs: Lactic acidlevel: 41 ABG: Initial Assessment 25 minutes later pH 7.46 7.45 Arterial PCO2 27 30 Arterial PO2 86 89 Carboxyhemoglo bin 29% 27% CXR: shows no lung infiltrates
- 69. In additionto placing the patient on 100% O2, which of the following is the mostappropriate next step in management? a) Blood cyanide level measurement b) Hyperbaric oxygen therapy c) Intubation and initiation of mechanical ventilation d) Pulse oximetry
- 70. In patientswith CO toxicity and high levels of carboxyhemoglobin, hyperbaric O2 therapy greatly speeds the clearance of carboxyhemoglobin and has been shown to reduce the incidence of delayed neurocognitive impairment.