Hypothermia

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Hypothermia Why Am I So Cold?

• David Feldstein, MD
• Primary Care Conference
• 5/26/04

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Objectives

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

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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.

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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

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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

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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

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Definition of Hypothermia

• Mild 32-35C (90-95F)
• Moderate 28-32C (82-90F)
• Severe lt 28C (82F)

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Causes of Hypothermia

• Decreased Heat Production
• Increased Heat Loss
• Impaired Thermoregulation
• Miscellaneous

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Decreased Heat Production

• Endocrine
• Hypopituitarism
• Hypoadrenalism
• Hypothyroidism
• Insufficient Fuel
• Hypoglycemia
• Malnutrition
• Neuromuscular Inefficiency
• Extreme Age
• Impaired Shivering
• Inactivity

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Increased Heat Loss

• Environmental Exposure
• Induced Vasodilation
• EtOH
• Drugs
• Skin
• Burns
• Psoriasis
• Iatrogenic
• Cold Infusions

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Impaired Thermoregulation

• Peripheral Failure
• Neuropathies
• Central Failure
• Metabolic
• Drugs
• Trauma
• CVA
• Hypothalamic dysfunction
• MS
• Wernickes

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Miscellaneous

• Sepsis
• Pancreatitis
• Carcinomatosis
• Uremia

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Kramer et al.

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

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(No Transcript)
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Prognosis of Hypothermia (Kramer)

• In hospital mortality 74
• Acute renal failure 12
• DIC 9

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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

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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

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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

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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

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Osborne Waves
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Antipsychotics in Hypothermia

• Chlorpromazine (Thorazine) attempts to use to
  induce hypothermia in 1950s
• 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

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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)

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Possible Mechanism

• Hypothalamus
• Dopamine receptor antagonism
• Serotonin (5-HT2) antagonism
• Periphery
• Alpha receptor antagonism
• Preventing vasoconstriction

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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

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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.