Hypothermia – Why Am I So Cold?

David Feldstein, MD

Primary Care Conference

5/26/04

Objectives

Etiologies of hypothermia Clinical manifestations of hypothermia Causes of hypothermia in psychiatric

patients

I have not received any financial compensation for this talk

Case

CC: DeleriumHPI: 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.

Case (cont)

PMH Gunshot wound to the head Paranoid schizophrenia HTN NMS secondary to ClozarilMeds: Aripiprazole (Abilify), ClonazepamSH Institutionalized for 20 years No access to tobacco, alcohol or illicit drugs

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

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

Definition of Hypothermia

Mild 32-35°C (90-95°F) Moderate 28-32°C (82-90°F) Severe < 28°C (82°F)

Causes of Hypothermia

Decreased Heat Production Increased Heat Loss Impaired Thermoregulation Miscellaneous

Decreased Heat Production Endocrine

HypopituitarismHypoadrenalismHypothyroidism

Insufficient FuelHypoglycemiaMalnutrition

Neuromuscular InefficiencyExtreme Age Impaired Shivering Inactivity

Increased Heat Loss Environmental Exposure Induced Vasodilation

EtOHDrugs

SkinBurnsPsoriasis

IatrogenicCold Infusions

Impaired Thermoregulation Peripheral Failure

Neuropathies Central Failure

MetabolicDrugsTraumaCVAHypothalamic dysfunctionMSWernicke’s

Miscellaneous

Sepsis Pancreatitis Carcinomatosis Uremia

Kramer et al.

Retrospective screening of patients over 60 with hypothermia in a community hospital in Jerusalem (1983-86)

Prognosis of Hypothermia (Kramer)

In hospital mortality – 74% Acute renal failure – 12% DIC – 9%

Back To My Patient 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

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

Clinical Manifestations CNS – amnesia, apathy decr level of

consciousness 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

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

Osborne Waves

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 19888 institutionalized patients with schizophreniaMeasured oral temp off antipsychotics then on

Haloperidol and then on ClozapineOral temp dropped on both antipsychoticsGreater drop with clozapine

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 1989Found 22% of older patients with hypothermia in one

hospital were on antipsychotics (thioridazine most common)

Possible Mechanism

HypothalamusDopamine receptor antagonismSerotonin (5-HT2) antagonism

PeripheryAlpha receptor antagonism

Preventing vasoconstriction

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

References:1. Danzl DF, Prozoz RS. Accidental Hypothermia. NEJM

1994; 331(26):1756-60.2. Hanania NA, Zimmerman JL. Environmental Emergencies:

Accidental Hypothermia. Critical Care Clincs 1999; 15(2):235-49.

3. Kramer MR, Vandijk J, Rosin AJ. Mortality in elderly patients with thermoregulatory failure. Archives of Internal Medicine 1989; 149(7):1521-3.

4. Heh CW, Herrera J, DeMet E, et al. Neuroleptic-Induced Hypothermia Associated with Amelioration of Psychosis in Schizophrenia. Neuropsychopharmacology 1988; 1(2):149-56.

5. Schwaninger M, Weisbrod M, Schwab S. Hypothermia Induced by Atypical Neuroleptics. Clinical Neuropharmacology 1998; 21(6):344-6.