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hyperthermia (pyrexia)

Severe hyperthermia is a core body temperature > 40.0 C (104.0 F) Etiology: - failure of normal thermoregulation - hyperthermia without fever may result from a) failure to adequately dissipate body heat in a hot environment - heat stroke, exertional & non exertional b) drug-induced hyperthermia - malignant hyperthermia - neuroleptic malignant syndrome - severe serotonin syndrome [3] - withdrawal from Sinemet [3] - true fever may arise from numerous sources including a) infection b) inflammation c) infarction or trauma d) neoplasms e) endocrinpapthies & metabolic disorders - pheochromocytoma - hyperthyroidism Pathology: - the critical thermal maximum of 42 degrees C (107.6 degrees F) above which cellular dysfunction, multiple organ failure & often death Clinical manifestations: - altered mental status - loss of consciousness - seizures - muscle rigidity - rhabodomyolysis - renal failure Complications: - maternal temperature > 38.5 C increases risk of neural tube defects [3] - acute renal failure - liver failure - acute respiratory distress syndrome (ARDS) - shock - disseminated intravascular coagulation (DIC) - rhabdomyolysis - electrolyte abnormalities - aspiration pneumonia Differential diagnosis: - heat stroke: encephalopathy & fever [3] - malignant hyperthermia [3] - exposure to volatile anesthetics - rigidity of masseter, increased pCO2 - neuroleptic malignant syndrome [3] - exposure to neuroleptics or abrupt discontinuation of Sinemet - altered mental status, severe rigidity, tachycardia, hypertension - no myoclonus, hyporeflexia - serotonin syndrome [3] - SSRI + other drug that increases serotonin release or inhibits metabolism - agitation, rigidity, myoclonus, hyperreflexia Management: see specific disorder

Related

heat injury; heat stress; heat illness hyperthyroidism neuroleptic malignant syndrome pheochromocytoma; paroxysmal hypertension; adrenal medullary paraganglioma; chromoffinoma temperature

Specific

drug-induced hyperthermia fever malignant hyperthermia/hyperthermia of anesthesia

General

disorder of temperature regulation sign/symptom

References

  1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 2, 830
  2. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 88
  3. Medical Knowledge Self Assessment Program (MKSAP) 11, 17. American College of Physicians, Philadelphia 1998, 2015 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  4. Suarez L et al, The effect of fever, febrile illness, and heat exposures on the risk of neural tube defects in a Texas-Mexico border population. Birth Defects Res A Clin Mol Teratol 70:815, 2005 PMID: 15468073
  5. Hyperthermia-Too Hot for Your Health http://www.niapublications.org/engagepages/hyperther.asp