What is the workup for a patient presenting with feeling cold due to temperature irregularities?

Workup for Temperature Irregularities: Feeling Cold

The workup for a patient presenting with feeling cold due to temperature irregularities should begin with core temperature measurement and assessment of severity based on both temperature readings and clinical presentation, followed by systematic evaluation of potential causes. 1

Initial Assessment

Temperature Measurement and Classification

• Obtain core temperature using reliable methods:
  • Esophageal or nasopharyngeal probes (most accurate)
  • Bladder temperature probe
  • Oral temperature (if patient is alert)
  • Tympanic measurement (if oral not feasible)
  • Avoid axillary measurements (consistently 1.5-1.9°C below core) 2

Severity Classification

Severity Level	Temperature	Clinical Signs
Cold stress	35-37°C	Alert, possibly shivering
Mild hypothermia	32-35°C	Altered mental status, shivering
Moderate hypothermia	28-32°C	Decreased responsiveness, ±shivering
Severe/profound	<28°C	Unresponsive, appears lifeless, slow heart rate and breathing

Caution: Clinical presentation may not always correlate with core temperature. Some patients with severe hypothermia (<28°C) may present with symptoms more consistent with mild hypothermia. Always base treatment decisions on core temperature measurements. 3

Diagnostic Workup

History

• Environmental exposure (duration, conditions)
• Clothing status (wet/dry)
• Recent activities
• Medication use (sedatives, vasodilators)
• Substance use (alcohol, drugs)
• Comorbidities (especially endocrine, cardiovascular, neurological)
• Trauma history

Physical Examination

• Vital signs (heart rate, blood pressure, respiratory rate)
• Mental status assessment
• Skin examination (color, moisture, evidence of frostbite)
• Neurological examination
• Cardiovascular examination (dysrhythmias, hypotension)
• Respiratory examination

Laboratory Tests

1. Complete blood count
2. Comprehensive metabolic panel
3. Thyroid function tests (TSH, free T4) 4, 5
4. Cortisol level
5. Blood glucose
6. Arterial or venous blood gas
7. Coagulation studies
8. Lactate level
9. Creatine kinase (for rhabdomyolysis)
10. Toxicology screen (if indicated)
11. Blood cultures (if infection suspected)

Imaging and Other Studies

1. Electrocardiogram (look for Osborn J waves, arrhythmias, prolonged intervals)
2. Chest X-ray
3. CT head (if altered mental status without clear cause)
4. Additional imaging based on suspected secondary causes

Evaluation of Underlying Causes

Primary Hypothermia

• Environmental exposure
• Inadequate clothing
• Immersion in cold water

Secondary Hypothermia

1. Endocrine disorders:

   • Hypothyroidism (check TSH, free T4) 4, 5
   • Hypoadrenalism
   • Hypopituitarism
   • Diabetes (hypoglycemia)

2. Metabolic disorders:

   • Hypoglycemia
   • Malnutrition
   • Uremia

3. Neurological disorders:

   • Stroke
   • Trauma
   • Parkinson's disease
   • Spinal cord injury

4. Cardiovascular disorders:

   • Heart failure
   • Shock states

5. Medications/Toxins:

   • Alcohol
   • Sedatives
   • Antipsychotics
   • Opioids
   • Carbon monoxide

6. Infections:

   • Sepsis
   • Pneumonia
   • Meningitis

7. Other:

   • Severe dermatological conditions
   • Burns
   • Dehydration

Management Approach

Immediate Interventions

• Move to warm environment
• Remove wet clothing
• Apply passive warming (dry blankets, covering head/neck) 2
• Position insulation between patient and ground
• For mild hypothermia: passive rewarming often sufficient
• For moderate to severe hypothermia: active rewarming required 1

Active Rewarming Techniques

• External rewarming:

  • Forced air warming blankets
  • Chemical heat packs (with insulation between pack and skin)
  • Warm blankets

• Core rewarming (for moderate to severe cases):

  • Warm IV fluids (37-40°C) at 30 mL/kg 1
  • Heated humidified oxygen
  • Body cavity lavage (for severe cases)
  • Extracorporeal warming (for severe cases or cardiac arrest) 2

Monitoring During Rewarming

• Continuous core temperature monitoring
• Cardiac monitoring (watch for arrhythmias)
• Blood pressure monitoring
• Target rewarming rate: 0.25-0.5°C per hour 2, 1
• Stop active rewarming once temperature reaches 37°C 1

Complications to Monitor

• Rewarming shock
• Electrolyte abnormalities
• Coagulopathy
• Cardiac arrhythmias
• Rebound hyperthermia
• Rhabdomyolysis

Special Considerations

• Handle patients with moderate to severe hypothermia gently to prevent arrhythmias 1
• For patients with decreased responsiveness, activate emergency response system 2
• Provide high-calorie foods/drinks for alert patients with cold stress or mild hypothermia 2
• Consider thyroid function testing in all cases without clear environmental cause 4, 5
• For hypothyroidism, initiate levothyroxine at appropriate dosage based on age and cardiac status 4

Common Pitfalls to Avoid

1. Relying on clinical presentation alone without measuring core temperature
2. Using unreliable temperature measurement methods (e.g., axillary)
3. Failing to consider secondary causes in patients with mild hypothermia
4. Rewarming too rapidly (>0.5°C/hour)
5. Rough handling of moderately to severely hypothermic patients
6. Missing underlying endocrine disorders, particularly hypothyroidism
7. Overlooking the need for cardiac monitoring during rewarming