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Thats Hot! Dr. Kelly Kasteel Case Study- hyperthermia.

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Presentation on theme: "Thats Hot! Dr. Kelly Kasteel Case Study- hyperthermia."— Presentation transcript:

1 Thats Hot! Dr. Kelly Kasteel Case Study- hyperthermia

2 Hyperthermia: Epidemiology 4,000 heat related deaths yearly (US) 80% of the fatalities are elderly – Occurs in 5 per million over age 85 compared to 1 per million in the 5-44 age group 2 nd leading cause of death among young athletes Very young (<4yo) also at increased risk – Occurs in 0.3 per million compared to 0.05 per million in patients > 4yo.

3 Case Study-History 36 y.o female Admitted-RCH 2011 (73 previous visits) Vancouver is experiencing a rare heat wave where outside temperatures have ranged between degrees Brought in via EHS agitated, spitting, naked and running into traffic at the scene. Hx of ? 45 second seizure en route to the hospital which is not clearly documented. Remote history of foul stools over the previous week before admission Without complaint at arrival, but…had precipitous decrease in LOC and was intubated for airway protection

4 Case Study-History PMHx 1. Hepatitis C. 2. BAD Meds – None. Previously (1/12) on Risperidone-2mg qhs via pharmanet Allergies – None SHx – Prostitution – multiple STDs in past – Polysubstance abuse (cocaine/heroine IVDU). – Last used this am

5 Case Study-On Examination HR-144 reg/ RR-22/ Temp-41 C/ BP-90/40/ Pressure support 15, PEEP of 5, FiO2 of 0.5, CPP was 11, mixed venous 81% and a MAP of 75 with no pressor support. Spent 8 hrs in ED before transfer to ICU

6 Case Study-On Examination CVS-s1s2 no murmur no s3s4 Resp- eae no wheeze no crackles Abdo-soft non-tender GU – ++discharge, no FB Neuro- Initially the ED, the pt was confused and combative with a GCS E3M5V2 = 10. Moving all 4. Pupils 3 reactive. MSK- Injection marks over antecubital space Derm- Warm and Dry

7 Case Study- Labs Glucose-6.8 Sodium-142 Potassium-5.4 Chloride104 Bicarb 11 Urea 6.3 Creatinine 147 Total Bili 8 Osmolality 319 Anion Gap-27 CK -405 Troponin0.19 Amylase-1018 TSH B-HCG- weakly positive Ethalene glycol/methanol- cancelled Tox serum screen (asa- weakly positive 0.2, acetaminophen, etoh)-negative

8 Case Study- Labs Infectious workup – Genital C/S- Normal flora – Stool C/S – Negative – Sputum-Negative – Urine –Negative – Blood C/S- 1 bottle gram positive cocci in clusters-coag negative staphlococcus Hypoglycemia- Glucose-0.7 (24 hrs after admission) Hyponatremia-Sodium-128 ARF-Creatinine-600 APTT-189 INR >9 (july 12) Fibrinogen-1.0 D- dimmer >4000 Hepatitis-AST 1000, ALT 5573, GGT 66, BR 666(total)) Blood smear-schistocytes, burr cells

9 Case Study-Imaging CT head- July 24th There is severe compression of structures in the fourth ventricle. Fluid around the brainstem has been effaced and the fourth ventricle is compressed. The patient is at risk for developing transtentorial or tonsillar herniation. Severe cerebral edema. CXR: small lung volumes, no obvious airspace disease

10 Case study- Course in Hospital Treated presumptively as sepsis nyd- piptazo, flagyl Negative workups – no identifiable septic or obstetrical causes for DIC. July Patient briefly extubated before re- intubation and markedly decreased LOC. Brain Death Comfort care initiated July 24 th, patient deceased within the hour. Autopsy- Non-contributory to date-MOS

11 Now Thats HOT What is your differential diagnosis for this pt? What are the potential complications that can occur in heat stroke? What investigations should you order? What other therapies should be considered?

12 Basic principles of Heat 4 mechanisms that allow the body to maintain a constant core temperature – Radiation – Convection – Conduction – Evaporation

13 Fever vs. Hyperthermia Fever – Elevation of body temp due to the resetting of the hypothalamic set point in response to endogenous or exogenous pyrogens Hyperthermia – Elevation of body temp above the hypothalamic set point due to the failure of the bodys heat dispersing mechanisms

14 Diff Dx - Hi temp with altered mental state

15 Heat Stroke Total breakdown of bodys thermoregulatory system Leads to multiorgan damage if left untreated A true medical emergency 2 forms described – Exertional – Non-exertional/Classical

16 Exertional Heat Stroke Occurs in young, healthy individuals engaged in heavy exercise during periods of high ambient temperature and humidity One series of 58 patients with heat stroke found an acute mortality rate of 21 percent (Ann Intern Med 1998 Aug 1;129(3):173-81)

17 Non-exertional heat stroke Affects individuals with underlying chronic medical conditions that either impair thermoregulation or prevent removal from a hot environment. Conditions include: – Cardiovascular disease – Neurologic or psychiatric disorders – Obesity – Anhidrosis – Extremes of age – Anticholinergic agents or diuretics

18 Diff Dx - Hi temp with altered mental state INFECTIOUS – Sepsis, Meningitis/Encephalitis, Falciparum malaria DRUG/TOXIN INDUCED – Overdose – anticholinergic, sympathomimetic – Withdrawal – benzodiazepene, alcohol – delirium tremens – Neuroleptic malignant syndrome – malignant hyperthermia – Serotonin syndrome ENDOCRINE – Thyroid storm, Pheochromocytoma CNS – Hypothalamic hemorrhage, status epilepticus esp nonconvulsive

19 Neuroleptic Malignant Syndrome Impaired thermoregulation in hypothalamus due to relative lack of dopamine Caused by antipsychotic meds/neuroleptics Distinguishing features – hyperthermia, – altered mental status – "lead pipe" muscle rigidity,choreoathetosis, tremors – autonomic dysfunction- diaphoresis, labile blood pressure, and dysrhythmias – Hx of psychotic disorder/neuroleptic medication use Treatment – Cooling, hydration, benzodiazepines – Bromocriptine, amantadine, dantrolene

20 Malignant Hyperthermia Rare (autosomal dominant) Genetic instability of sarcoplasmic reticulum causing massive calcium release Onset: 1 to 10 hours after exposure Triggered by inhalational anaesthetic or succinylcholine Distinguishing features – History of succinylcholine use – Muscular rigidity Treatment – Cooling, hydration – Dantrolene

21 Serotonin syndrome Excess serotonin and dopamine levels in CNS Triggered by any med that increases serotonin levels (eg. SSRIs, demerol, dextromethorphan, lithium etc.) Distinguishing features – Appropriate medication history – Muscular rigidity Treatment – Cooling, Hydration – Cyproheptadine

22 Thyroid storm Hypermetabolic state from extreme thyrotoxicosis Distinguishing features – History of thyroid disease – Goiter – Ophtho clues lid retraction/lag, exophthalmos, EOM palsy Treatment – Cooling, Hydration – PTU, iodide solution, propranolol etc.

23 Overdose Anticholinergics, sympathomimetics Distinguishing features – Hx of ingestion – Toxidromes Treatment – Cooling, hydration – Benzodiazepine, Decontamination

24 Diff Dx contd The differential for heat stroke contains many potentially life threatening illnesses It all comes down to your ABC Cooling Hemodynamic support

25 Heat Stroke – Complications CNS – Cerebral edema – Permanent neuro damage eg. cerebellar deficits, hemiplegia, or dementia is possible after severe cases Renal – Myoglobinuric renal failure- rhabdomyolysis Cardiopulmonary – Heart failure – Pulmonary edema

26 Heat Stroke - Complications Electrolyte – Hypo or Hyperkalemia – Hypernatremia – Hypocalcemia, hypomagnesemia Hematologic – Thrombocytopenia – DIC Hepatic – Centrilobular necrosis – not permanent – However, can be a useful diagnostic adjunct

27 Heat Stroke – Hepatic Damage Hepatic damage is such a consistent feature of heat stroke that its absence should cast doubt on the diagnosis From Rosens 5 th edition p2003

28 Heat Stroke - Diagnostic Criteria Classic triad – Markedly elevated temp ( >40.5 degrees ) – CNS dysfunction – Anhidrosis Caveats – Sweating seen 50% of the time esp. in exertional heat stroke

29 Investigations CBC+diff, blood culture Infection, thrombocytopenia Electrolytes, ABG Electrolyte derangement, acidosis Chemstrip/Glucose DKA BUN, Cr Renal failure U/A, urine for myoglobin Rhabdomyolysis Hepatic panel Liver damage INR, PTT, Fibrinogen etc DIC CT Head Intracranial event, pre-LP LP Meningitis/encephalitis Thyroid panel Thyrotoxicosis CXR Pulmonary Edema EKG Secondary ischemia

30 Initial management

31 Treatment summary The Basics… – Resusc room, oxygen, iv, monitors – Vitals-including continuous rectal temp monitoring The ABCs… – Airway, Breathing – Cooling Evaporative/Immersive +/- adjuncts – Circulation Cautious rehydration Pressor support as needed

32 Treatment summary contd More ABCDEs…. +/- Antibiotics? Sepsis, meningitis +/- Benzodiazepines ? Withdrawal syndrome +/- Cyproheptadine ? Serotonin syndrome +/- Dantrolene ? Malignant Hyperthermia ? Neuroleptic Malig Syndrome +/- Decontamination ? Ingestion +/- Endocrinopathy tx ? Thyroid storm

33 What about antipyretics? Acetaminophen and ASA are not indicated in heat stroke – These drugs counteract fever caused by an elevated hypothalamic set point – In heat stroke, the increased temperature is due to an entirely different mechanism ASA --> may worsen coagulopathy Acetaminophen --> may exacerbate hepatic damage

34 Cooling The key to successful outcome in heat stroke Prognosis in heat stroke is directly related to how quickly the body can be cooled down Goal is to cool by degrees/min

35 In the ER ….Cooling Methods Immersion Evaporation

36 Ice Water Immersion Primary cooling mech = conduction Pt is undressed and placed into a tub of ice water deep enough to cover the trunk and extremities Can achieve cooling rates of 0.13 degrees/min Can decrease core temp to 39 degrees in min

37 Ice Water Bath-Disadvantages Cant perform defibrillation or resuscitative procedures while immersed Vasoconstriction Shunting of blood from the skin ? Heat exchange Induced shivering endogenous heat production Uncomfortable

38 Evaporative Cooling Fans positioned beside an undressed pt while warm water is sprayed/sponged on Pt kept continually wet for continued cooling Can achieve cooling rates comparable to immersive techniques

39 Evaporative Cooling-Advantages Easier patient access No induced peripheral vasoconstriction Less induced shivering More comfortable for the patient

40 Methods of Cooling Br J Sports Med 2005 Aug;39(8):503-7 Review of 17 journal articles. Modalities of reducing body core temperature in patients with exertional heatstroke The most effective method is immersion in iced water – The practicalities of this treatment may limit its use

41 Cooling Goal Keep rectal temperature <39.4ºC and skin temperature 30ºC-33ºC. Cooling should be discontinued when rectal temp hits degrees – to avoid overshoot hypothermia Avoid: – antipyretic agents – Alcohol sponge baths – Alpha-adrenergic agonists

42 Main Predictors of Outcome Duration and degree of hyperthermia Time to cooling Indicators of organ dysfunction, such as transaminases, LDH and CK

43 Cooling methods contd To counteract shivering… – Benzodiazepines – Phenothiazines – advocated in the past, however may potentially lower seizure threshold – If severe- non-depolarizing paralytic

44 Circulation – Main Issues Hypotension and dehydration are the main issues for heat stroke patients Usually, more than one cause for hypotension – Hypovolemia – Increased peripheral vasodilatation

45 Circulation – Complicating factors Heat stroke patients are at high risk of developing pulmonary edema and renal failure Cooling a patient will redistribute peripheral blood flow back to the core Need careful balance between hydration and preventing fluid overload

46 Circulation-Approach to hypotension 1 st line – cooling – Will redistribute volume from periphery to core 2 nd line – judicious hydration – Most sources suggest cc/h – Titrate to hemodynamic response, urine output, age and PMHx of patient etc. – Invasive monitoring may be indicated for complicated cases

47 Circulation-Approach to hypotension 3 rd line – pressors – Be cautious with primarily alpha blocking agents (eg. Levophed) Will cause further vasoconstriction and could potentially decrease heat exchange – No definitive evidence on which pressor is the best to use

48 Heat exhaustion vs Heat stroke Important to think of heat exhaustion and heat stroke as two ends of a spectrum The point at which heat exhaustion becomes heat stroke --> when thermoregulatory mechanisms fail or are overwhelmed Heat exhaustion can easily progress to heat stroke if not adequately treated Thus early recognition and treatment essential!

49 Heat exhaustion vs. Heat stroke - Differentiation Vital signs – In general, heat exhaustion 40 deg – Remember though that prehospital cooling may have occurred in the heat stroke patient Clinical exam – Heat stroke implies significant CNS dysfunction – seizures, coma, very altered mental state – Pts with heat exhaustion have less florid CNS dysfunction- eg. mild disorientation, clumsiness

50 Heat exhaustion vs. Heat stroke- Bottom line If the possibility of heat stroke is entering your mind, initiate immediate tx (ie Airway, Breathing, Cooling, Diff Dx) Hepatic transaminases may be a useful differentiating factor – but you must initiate immediate cooling while you wait for results

51 Take Home Points Altered mental state + hyperthermia = heat stroke until proven otherwise ABCs = Airway, Breathing, Circulation, Cooling Treat hyperthermia early or patient dies

52 References Rosens 5th edition, pages Tintinallis 5th edition, pages Khosla et al, Heat-Related Illnesses, Critical Care Clinics, 15(2), Tek et al, Heat Illness, Emergency Medicine Clinics of North America, 10(2), Wexler, Randall K, Evaluation and Treatment of Heat-Related Illnesses, American Family Physician, 65(11),

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