Heat-related illness - ACEM Fellowship Notes

see also: [Dunn Heat stroke](x-devonthink-item://937F43CB-2A96-45BF-ADE6-F028CA1B47EB), [Tintinalli Heat emergencies](x-devonthink-item://FEDB96F9-3A4C-48E0-94CF-9ECFCE5D8E93?page=12), [Illicit Drug Induced Hyperthermia - EMA 2025](bookends://sonnysoftware.com/ref/DL/259320) See: symptoms/[[Hot and bothered]] > [!Key Points] > - exercise-associated collapse is the jost common heat and exercise-related illness > - A core body temperature around or greater than **41.5°C** results in progressive denaturing of a number of vital cellular proteins, failure of vital energy-producing processes and loss of cell membrane function > [!treatment] > **reduce core temperature to <42 deg within 15 min of ED arrival** > - *rapid cooling* > - ==evaporative cooling==: spray skin with tepid water and blow with air > - ==immersion cooling==: into cold or ice water > - early neuromuscular paralysis and intubation > - support circulation and organ function # Exercise-associated Collapse - most common heat-related illness - end of race, muslce pump venous return ceases --> reduced cardiac output - leads to collapse and LOC - tachycardia and orthostatic hypotension - **temp < 40 deg C** ## Treatment - supine - elevate legs - oral fluids - ==do not give IVF== as worsenins hyponatremia as inappropriate antidiureitic hormone levels # Heatstroke > [!warning] Clinical features (Classic triad) > - neurological dysfunction > - temp >41.5 deg C > - hot, dry skin note: may not have all these features ==loss of consciousness== is constant feature of heatstroke, but may regain consciousness in ED The cerebellum is highly sensitive to heat, and ataxia can be an early neurologic finding. [[Seizures]] are common during cooling **Causes** - "Exertional" heat stroke occurs in the presence of excess physical activity and normal thermoregulation - "Non-exertional" heat stroke occurs in the presence of normal physical activity and impaired thermoregulation **investigations** - UEC - hypokalemia - hyperphosphatemia - hyper Ca - hyper K and ↓ Ca may be present if [[rhabdomyolysis]] has occurded - [[hyperglycaemia|glucose elevated]] elevated in up to 70% - abnormal LFT often seen in exertioanl heat stroke - usually AST and LDH - LDH >1000 indicates severe hepatic/renal/myocardial demage - Creatine Kinase - usually 10,000 - 1,000,000 in rhabdomyolysis - levels usually rise in first 24 hours - myoglobin may be elvated - ECG - [[Long QT]] most common ?related to ↓ Ca, ↓ K, ↓ Mg - conduction defects - can get sinus tach, AF, SVT - WCC 30-40,000 - [[DIC]] possible - lactic acidosis ## Heatstroke cooling treatment - Aggressive cooling - ice water immersion - pros are it is rapid and easy to do - cons are can cause peripheral vasoconstriction and shivering, difficult to do with an unstable patient - cool water immersion - iced peritoneal lavage - remove clothing - pack neck, axillae, groin with ice bags - +/- IVF for fluid deficits if hypotensive - use NaCl, avoid K/lactate containing fluids - judicious fluids; can result in pulm oedema - shivering, seizures, muscle activity -- chlropromazien, benzos, paralysis - *no role* for dantrolene in heat stroke ==aspirin and paracetamol are not useful== | cooling technique | advantage | disadvantage | rate of cooling / min deg C | | ---------------------------------------------------------------------- | ---------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- | --------------------------- | | evaporative cooling (spray skin with tepid water and blow with air) | - readily available/ effective - practical and well-tolerated | - can cause shivering - less effective in humid environment - difficult to keep ECG monitoring on | 0.31 | | immersion cooling | rapid effective effects | peripheral vasoconstriction and shivering - cannot do with low GCS or unstable patient | 0.15 - 0.24 | | ice packs to neck, axillae, groin | practical in resus situations adjuvant to other cooling methods | longer cooling times than other modalities modest efficacy poor tolerance/compliance | 0.04 - 0.08 | | cooling blankets | easy to apply readily available | limited efficacy impede use of other cooling techniques not recommended if other methods available | | | cold water gastric/urinary bladder or peritoneal lavage | can be done in ED | labour intensive, invasive, potential sodium shifts / water intoxication, effectiveness not validated | 0.56 | | cardiopulmonary bypass | fast and effective cooling can be used in severe or resistant cases | invasive, not readily available, labour intensive | | ## DDx - [[Neuroleptic Malignant Syndrome|NMS]] -- look for muscle rigidity - malignant hyperthermia -- very rare - [[Serotonin Syndrome]] -- rare to have temp >39 deg. clonus is key to dx - [[thyrotoxicosis|thyroid storm]] - stimulant tox - seosis # Related Questions ## cooling - [ ] 2Q: [Hyperthermia](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=1) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=0) - [ ] 3Q: [Seizure](x-devonthink-item://5DC0999B-D537-4002-86AF-FD7B54B45E2E?page=46) -- [Answer](x-devonthink-item://406AF611-5CD4-4B3B-9795-327E8F4E3626?page=21) - [ ] 4Q: [Toddler with Hyperthermia](x-devonthink-item://09CFA1A7-00F1-4151-979E-8F3984924D54?page=9) -- [Answer](x-devonthink-item://CF5E9C2B-42F9-4F9C-AC29-877E20134927?page=5) ## heat related illness - [ ] 6Q: [Heat related illness](x-devonthink-item://4BE7EDE1-1843-4BA0-B8D2-0DCEF50784D4?page=12) -- [Answer](x-devonthink-item://15F8F701-8EC8-4F9A-8DEC-5220C8561C8A?page=10) - [x] DUPLICATE Q: [Heat Stroke](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=1) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=0) - [ ] 7Q: [Just another reason to not attend music festivals](x-devonthink-item://EF003416-CCE0-4A7D-AE59-F054D2880322?page=8) -- [Answer](x-devonthink-item://30A6ADA2-CC99-445A-B901-7117A6AEB2CC?page=8) - [ ] 8Q: [Heat Related Illness](x-devonthink-item://92A26505-5B6B-4ADD-995F-6AAA2E05C637?page=8) -- [Answer](x-devonthink-item://0808A030-AF19-4671-BE84-3E8BCBEC6124?page=8) - [ ] 9Q: [Heat Related Illness](x-devonthink-item://3F154834-B3DA-4ADD-8596-C57D6EC9C8A8?page=16) -- [Answer](x-devonthink-item://CF07FAA1-C055-4A43-BFEE-A0DA2DD95452?page=10) - [x] DUPLICATE Q: [Toddler with Hyperthermia](x-devonthink-item://09CFA1A7-00F1-4151-979E-8F3984924D54?page=9) -- [Answer](x-devonthink-item://CF5E9C2B-42F9-4F9C-AC29-877E20134927?page=5) ## heat stroke - [ ] 10Q: [Heatstroke](x-devonthink-item://554C45F7-8661-4467-BD61-8A79B6ECABF4?page=93) -- [Answer](x-devonthink-item://554C45F7-8661-4467-BD61-8A79B6ECABF4?page=94) - [ ] 11Q: [Heat Stroke](x-devonthink-item://4134DDB3-6E12-474A-9F6F-64135C0C6048?page=2) -- [Answer](x-devonthink-item://AC92B5F1-8EE6-461A-B03E-F70AE7DC1275?page=1) - [x] DUPLICATE Q: [Heat related illness](x-devonthink-item://4BE7EDE1-1843-4BA0-B8D2-0DCEF50784D4?page=12) -- [Answer](x-devonthink-item://15F8F701-8EC8-4F9A-8DEC-5220C8561C8A?page=10) - [ ] 12Q: [Heat related illness](x-devonthink-item://EE8AC47E-BE40-4377-885E-FA9C91C8C262?page=14) -- [Answer]() - [x] DUPLICATE Q: [Heat Stroke](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=1) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=0) - [ ] 13Q: [Heat stroke](x-devonthink-item://85167CB5-A7B5-4BF3-9BC7-AC46D5538A42?page=1) -- [Answer](x-devonthink-item://5B03E66C-E043-4EB7-A5F6-7389CB927BD7?page=1) - [ ] 14Q: [Heat Stroke](x-devonthink-item://834C484F-DDAA-4819-8DF0-84AE5E70DA1D?page=28) -- [Answer](x-devonthink-item://D46998FE-62E2-4A3A-860D-C32C94B86E42?page=12) - [ ] 15Q: [Heat Stroke](x-devonthink-item://4AD9F692-A113-4718-94B0-7292F2273B1F?page=11) -- [Answer](x-devonthink-item://A10DE51E-92FA-42D1-8AA0-7AE68C2FA743?page=24) - [ ] 16Q: [Heat Stroke](x-devonthink-item://EE0B8625-5F19-46CF-8208-56D79DC48BC5?page=7) -- [Answer](x-devonthink-item://6F751245-A36C-447A-8AE7-599AD5871C71?page=12) - [x] DUPLICATE Q: [Heat Related Illness](x-devonthink-item://92A26505-5B6B-4ADD-995F-6AAA2E05C637?page=8) -- [Answer](x-devonthink-item://0808A030-AF19-4671-BE84-3E8BCBEC6124?page=8) - [x] DUPLICATE Q: [Heat Related Illness](x-devonthink-item://3F154834-B3DA-4ADD-8596-C57D6EC9C8A8?page=16) -- [Answer](x-devonthink-item://CF07FAA1-C055-4A43-BFEE-A0DA2DD95452?page=10) - [x] DUPLICATE Q: [Toddler with Hyperthermia](x-devonthink-item://09CFA1A7-00F1-4151-979E-8F3984924D54?page=9) -- [Answer](x-devonthink-item://CF5E9C2B-42F9-4F9C-AC29-877E20134927?page=5) ## hyperthermia - [x] DUPLICATE Q: [Heat related illness](x-devonthink-item://EE8AC47E-BE40-4377-885E-FA9C91C8C262?page=14) -- [Answer]() - [x] DUPLICATE Q: [Hyperthermia](x-devonthink-item://8AAAF35C-CCF4-4157-9551-5B05727AA0CD?page=1) -- [Answer](x-devonthink-item://FDFBA3A1-6207-4204-AB6D-7483D80C5B5C?page=0) - [x] DUPLICATE Q: [Seizure](x-devonthink-item://5DC0999B-D537-4002-86AF-FD7B54B45E2E?page=46) -- [Answer](x-devonthink-item://406AF611-5CD4-4B3B-9795-327E8F4E3626?page=21) - [ ] 18Q: [Unknown ingestion and seizure](x-devonthink-item://1EA9311E-0B9E-49F7-8D6E-4C4187A838C4?page=16) -- [Answer](x-devonthink-item://B1CB2E8F-5D04-49EE-8274-043871389D28?page=9)