Hypothermia – Why Am I So Cold?

1. Hypothermia – Why Am I So Cold? David Feldstein, MD Primary Care Conference 5/26/04

2. Objectives • Etiologies of hypothermia • Clinical manifestations of hypothermia • Causes of hypothermia in psychiatric patients • I have not received any financial compensation for this talk

3. Case CC: Delerium HPI: • 48 y.o. institutionalized man with hx schizophrenia • behavioral changes X 2 weeks • slurring of speech and decrease in ambulation and eating • labored breathing day of admission. • temperature 33.3 orally at his institution.

4. Case (cont) PMH • Gunshot wound to the head • Paranoid schizophrenia • HTN • NMS secondary to Clozaril Meds: Aripiprazole (Abilify), Clonazepam SH • Institutionalized for 20 years • No access to tobacco, alcohol or illicit drugs

5. Case (cont) PE: • T 33.2 rectal; HR 60; 129/76; RR 16; 95% RA • Gen: Spontaneously opening eyes and moving extremities. NAD • HEENT: Pupils 1mm and sluggish • Neck: Nonpalpable thyroid • Lungs: Bibasilar crackles with poor effort • CVS/Abd – WNL • Neuro: Not following commands, Nml tone, 1+ DTRs, No clonus • Skin: Cool to touch, no rashes • Ext: 1+ pitting edema to knees bilaterally

6. Hospital Course • Head CT and LP were performed • Blood cultures sent • Vancomycin and Zosyn started empirically • 12 hours after arrival in ED patient was found to be completely unresponsive to painful stimuli • Temp 33.3 rectal; HR 52; BP 125/72

7. Definition of Hypothermia • Mild 32-35°C (90-95°F) • Moderate 28-32°C (82-90°F) • Severe < 28°C (82°F)

8. Causes of Hypothermia • Decreased Heat Production • Increased Heat Loss • Impaired Thermoregulation • Miscellaneous

9. Decreased Heat Production • Endocrine • Hypopituitarism • Hypoadrenalism • Hypothyroidism • Insufficient Fuel • Hypoglycemia • Malnutrition • Neuromuscular Inefficiency • Extreme Age • Impaired Shivering • Inactivity

10. Increased Heat Loss • Environmental Exposure • Induced Vasodilation • EtOH • Drugs • Skin • Burns • Psoriasis • Iatrogenic • Cold Infusions

11. Impaired Thermoregulation • Peripheral Failure • Neuropathies • Central Failure • Metabolic • Drugs • Trauma • CVA • Hypothalamic dysfunction • MS • Wernicke’s

12. Miscellaneous • Sepsis • Pancreatitis • Carcinomatosis • Uremia

13. Kramer et al. • Retrospective screening of patients over 60 with hypothermia in a community hospital in Jerusalem (1983-86)

15. Prognosis of Hypothermia (Kramer) • In hospital mortality – 74% • Acute renal failure – 12% • DIC – 9%

16. WBC 1.9 –nml diff Hct 37 Plts 65 INR 1.1 / PTT 48.5 Na 140 K 5.7 Cl 110 CO2 25 Bun/Cr 23/1.0 Glucose 67 AST 62/ ALT 132 GGT 63 Tbili 0.4 TSH 5.16 / Free T4 0.8 Cortisol 18.6 Tox Screen – + benzos Head Ct – old trauma LP – 2 nucleated cells CXR- mild pulm edema ABG 7.26/61/105/26 Back To My Patient

17. Further Hospital Course • Transferred to TLC • Went for Head CT with contrast • Woke up in scanner and combatative • Temp 35.3 and patient back to baseline per caregivers • Given 10mg Haldol for outbursts • 1 hour after Haldol was again unresponsive with Temp 33.9

18. Clinical Manifestations • CNS – amnesia, apathy decr level ofconsciousness  coma • CVS – Tachy  brady  atrial/ventricular arrythmias  decreased co  asystole • Resp – Tachypnea  decr ventilation with bronchorrhea/bronchospasm  loss of airway protection  pulm congestion  apnea • Renal – Cold diuresis  decrease urine output • Endocrine – Incr catechols, adrenal steroids and thyroxine  decr insulin activity  decr BMR • Neuromuscular – Incr muscle tone  shivering  loss of shivering  rigidity  decr nerve-conduction and areflexia

19. Laboratory Manifestations • CBC – hemoconcentration/thrombocytopenia • Lytes – hyperkalemia/hypernatremia • Bun/Cr – increased • Glucose – intially increased then can be decreased • Coags – increased • ABG – hypercarbia/hypoxia/acidosis • EKG – bradycardia/Osborne waves/atrial or ventricular arrythmias

20. Osborne Waves

21. Antipsychotics in Hypothermia • Chlorpromazine (Thorazine) – attempts to use to induce hypothermia in 1950’s • Multiple case reports of typical and atypical antipsychotics causing hypothermia • Heh 1988 • 8 institutionalized patients with schizophrenia • Measured oral temp off antipsychotics then on Haloperidol and then on Clozapine • Oral temp dropped on both antipsychotics • Greater drop with clozapine

22. Antipsychotics in Hypothermia (cont) • Scwaninger 1998 • Describes 10 cases of hypothermia secondary to atypical antipsychotics reported to German Federal Institute for Drugs and Medical Devices • Kramer 1989 • Found 22% of older patients with hypothermia in one hospital were on antipsychotics (thioridazine most common)

23. Possible Mechanism • Hypothalamus • Dopamine receptor antagonism • Serotonin (5-HT2) antagonism • Periphery • Alpha receptor antagonism • Preventing vasoconstriction

24. Take Home • Hypothermia can occur without “cold” exposure • Antipsychotics may cause hypothermia much more commonly than we are aware • In the elderly hypothermia has a very poor prognosis • Without treatment hypothermia will progress with significant morbidity and mortality

25. References: • Danzl DF, Prozoz RS. Accidental Hypothermia. NEJM 1994; 331(26):1756-60. • Hanania NA, Zimmerman JL. Environmental Emergencies: Accidental Hypothermia. Critical Care Clincs 1999; 15(2):235-49. • Kramer MR, Vandijk J, Rosin AJ. Mortality in elderly patients with thermoregulatory failure. Archives of Internal Medicine 1989; 149(7):1521-3. • Heh CW, Herrera J, DeMet E, et al. Neuroleptic-Induced Hypothermia Associated with Amelioration of Psychosis in Schizophrenia. Neuropsychopharmacology 1988; 1(2):149-56. • Schwaninger M, Weisbrod M, Schwab S. Hypothermia Induced by Atypical Neuroleptics. Clinical Neuropharmacology 1998; 21(6):344-6.