Identify Hypothermia and Correctly Report Diagnoses in ICD-10-CM

Learn how to identify hypothermia and assign the appropriate ICD-10-CM codes here.

hypothermia coding for adults and newborns in ICD-10-CM

My Uncle Jim lives in Maine, where the winters get exceptionally cold. Last year he needed to save some money, so he turned his heat down to 62 degrees. That decision almost cost him his life.

When Uncle Jim’s daughter, my cousin Julie, arrived at his house, he was only wearing a light t-shirt, and the house was “frigid,” she stated. Julie said her dad was shivering, pale, speaking slowly, and was having trouble walking. She wrapped her dad in a blanket and dialed 911. It turned out that Uncle Jim had hypothermia.

Here is a 3-minute video explaining hypothermia.

Hypothermia and Its Etiology

There are basically two major types of hypothermia, according to One type is accidental, and the other type is intentional. Accidental usually happens when the body is exposed to cold temperatures that lower the body temperature. Intentional hypothermia is when a medical procedure is performed to lower the body temperature. In this article, we are going to discuss accidental hypothermia, which is what Uncle Jim experienced.

Hypothermia is a potentially serious condition that occurs when the body gets cold and loses heat faster than the body can make it. The body temperature drops to less than 96.08 °F (35.6 °C) and can be caused by cold water, getting cold in wet clothes, living in a cold home, and not having the appropriate dry clothing on for protection. Hypothermia is more common in the winter due to greater exposure, but it can also develop in milder climates.

Pathophysiology of Hypothermia

When a person is exposed to cold temperatures, most of the heat loss escapes through the skin, and the lungs exhale the rest. The hypothalamus is the part of the brain that controls body temperature, and it responds to body temperature changes by bringing them back in line.

During normal metabolic processes, the body regulates the core temperature by creating heat, cooling, or conserving heat. Heat conservation is done by peripheral vasoconstriction and by behavior. Producing heat is done by shivering and by increasing the levels of thyroxine and epinephrine.

As the body temperature falls, the core tries to warm itself as much as possible by keeping blood away from the skin and losing heat to the environment. The blood flow is directed to the heart, lungs, kidney, and brain, leading to possible frostbite of the fingers, toes, hands, feet, ears, and nose. When the body temperature falls to about 95 °F (35 °C), the heart, nervous system, and other organs stop working correctly. This can result in heart and respiratory system failure.

Risk Factors

Persons at risk for hypothermia:

  • Infants, children, and elderly without sufficient clothing, heating, or food
  • People with mental illness
  • People who spend a lot of time outdoors
  • People who walk on a body of water that is partially frozen
  • People in cold weather who are under the influence of drugs or alcohol
  • Some medications can put a person at risk

Medical conditions that may make it difficult for the body to regulate its internal temperature:

description of hypothermia



There are three grades of hypothermia, which may vary to some degree, as not all physicians agree with grading or fixed temperatures:

  • Mild hypothermia: core temperature 90-95 °F (32-35 °C) – shivering; cold, pale or blue-gray skin; lack of concern; poor judgment; mild unsteadiness in balance or walking; numb hands and fingers
  • Moderate hypothermia: core temperature 82-90 °F (28-32 °C) – problems performing simple tasks; slurred speech
  • Severe hypothermia: core temperature below 82 °F (28 °C) – muscles becoming stiff; slow pulse; breathing that is shallow and slower; weakness or sleepiness; extreme confusion; loss of consciousness; shivering ceases; coma that leads to death


Due to newborns, infants, and young children having a larger surface area than bodyweight and losing body heat quicker than others, their chances of developing hypothermia are higher. Therefore, the temperature values for hypothermia are a bit different for infants:

  • Mild hypothermia or cold stress: core temperature 96.8-97.5 °F (36.0-36.4 °C)
  • Moderate hypothermia: core temperature 89.6-96.6 °F (32.0-35.9 °C)
  • Severe hypothermia: core temperature below 89.6 °F (32 °C)

Infants and young children have a more challenging time communicating their symptoms with caregivers and medical providers. However, some of the signs of hypothermia to look for include:

  • rectal or armpit temperature below 97.5 °F (36.4 °C); skin cold and red; lethargic; low energy; weak cry; cool extremities and abdomen; poor feeding; hypoglycemia, hypoxia, apneic episodes; heart arrhythmias

Chronic hypothermia can occur in some infants and children, and the symptoms may include: weight loss, no weight gain, or failure to thrive.


If an adult’s temperature is taken and it is below 95 °F (35 °C), or an oral thermometer has no reading, it means medical attention is needed immediately. For an infant, it is 97.5 °F (36.4 °C). Diagnosis is made based on the patient’s history and physical exam, and treatment begins immediately. Bradycardia develops in some patients and is shown by an abnormal EKG.


Hypothermia is a potentially life-threatening condition that requires immediate attention. These steps should be taken while waiting for medical care to arrive:

  • Remove wet clothes, gloves, hats, shoes, and socks.
  • Shelter the person from wind and further heat loss by providing warm, dry clothes and blankets.
  • Carefully move the person to a dry, warm area when possible. This prevents the patient from developing ventricular fibrillation or another cardiac dysrhythmia.
  • Rewarm the person by applying chemical packs to the patient’s armpits, abdomen, and groin and add extra clothing and warm blankets. Use your own body heat if necessary.
  • Take the person’s temperature if possible.
  • Offer warm liquids, but avoid caffeine and alcohol since they cause the body to lose heat quicker.
  • Avoid massaging the extremities to warm them, using heat lamps, or putting the person in a hot bath.

If the person is unconscious or shows no sign of breathing, dial 911 and provide cardiopulmonary resuscitation (CPR) immediately. Continue CPR until paramedics get there. If the hypothermia is advanced, hospitalization is critical, so the body’s core temperature can be rewarmed.

Hospital treatment includes warm coverings, humidified oxygen, warmed intravenous saline, and internal washing of the abdominal cavity. Instilling warm fluid into the bladder is recommended in a severe case of hypothermia. Flushing the thoracic region with warm water with warmed isotonic saline is also sometimes done.

Complications during recovery may include pneumonia, heart arrhythmias, ventricular fibrillation, cardiac arrest, and death.It can be difficult to determine death in a hypothermic patient. Death should not be pronounced in a patient who appears to have suffered a cardiac arrest or as a result of hypothermia until they are rewarmed to 95 °F (35 °C).  


According to the National Institutes of Health, hypothermia can possibly be avoided with the proper preparation:

  • Keep the indoor temperature set to at least 68 degrees, especially for older people.
  • Dress warmly and in layers by covering your head, ears, fingers, and feet sufficiently. Hypothermia takes a while to take effect, but frostbite can take place within a short amount of time.
  • Avoid overexertion by taking breaks while performing outdoor physical activities.
  • Drink warm, non-alcoholic beverages, and avoid caffeine. Alcohol makes you feel warm when your body temperature may actually be lowering.


If the condition is treated quickly, recovery usually involves little to no consequences. However, if the person has more severe symptoms and residual problems, the prognosis may not be as good.

Some people may suffer from frostbite or be more prone to developing hypothermia in the future. Still, others may have other problems, such as alcoholism, mental health problems, or being elderly or homeless, contributing to a worse prognosis and even death.

More deaths related to hypothermia happen indoors rather than outdoors, probably because it affects older people, and the diagnosis is not made until it has progressed.

ICD-10-CM Coding

Let’s look at a couple of coding scenarios.

Case #1

A 56-year-old female was brought to the ER after being found outside her home unconscious. Her son states the patient had been outdoors shoveling her driveway for about an hour, and the temperature was only 4 degrees Fahrenheit. The patient was wearing only a light jacket and gloves and had nothing covering her head. Her blood-alcohol level was 120 mg/100 ml. The patient was admitted with a diagnosis of hypothermia, superficial frostbite of bilateral ear lobes, and acute alcohol intoxication.

The ICD-10-CM codes that should be assigned are:

  • T68.XXXA, Hypothermia, initial encounter
  • T33.011A, Superficial frostbite of right ear, initial encounter
  • T33.012A, Superficial frostbite of left ear, initial encounter
  • F10.129, Alcohol abuse with intoxication, unspecified
  • Y90.6, Blood alcohol level of 120-199 mg/100 ml
  • X31.XXXA, Exposure to excessive natural cold, initial encounter

Now let’s discuss how we came up with these codes.

The documentation states the diagnoses are hypothermia, superficial frostbite of bilateral ear lobes, and acute alcohol intoxication, so I need to be sure to assign for these conditions.

Hypothermia and Frostbite

First of all, we know the patient is an adult, and hypothermia in an adult is assigned a different code than hypothermia in a newborn is assigned, according to the ICD-10-CM Official Guidelines for Coding and Reporting FY 2022. The cause of hypothermia, in this case, is cold weather, so let’s look in the ICD-10-CM Index under Hypothermia, low environmental temperature (T68).

Then, in the Tabular under T68 Hypothermia, we see a few things: A symbol that indicates we need to use additional characters and an “X” to indicate we need to assign three placeholders.  A note also states, “The appropriate 7th character is to be added to code T68.” This is an initial encounter, so the appropriate code to be assigned is:

T68.XXXA, Hypothermia, initial encounter

Synonyms:  Accidental hypothermia, Hypothermia NOS

Some instructional notes need to be reviewed. For example, there is a note that states:

Use additional code note to identify the source of exposure:

Exposure to excessive cold of man-made origin (W93)

Exposure to excessive cold of natural origin (X31)

The hypothermia was due to the cold weather, which is of a natural origin, so we need a code from X31. Turning to X31 in the Tabular, we can see that this code also requires a 7th character with “X” as the placeholder, along with an “A” to indicate an initial encounter, making the correct code:

X31.XXXA, Exposure to excessive natural cold, initial encounter

Synonyms: Excessive cold as the cause of chilblains NOS, Excessive cold as the cause of immersion foot or hand, Exposure to cold NOS, Exposure to weather conditions

There is also an Excludes note at T68 that states, “Excludes2 frostbite (T33-T34).That means that if the patient were diagnosed with hypothermia and frostbite, both would need to be coded. They were, so we need to move on to the frostbite of the bilateral ear lobes. We already know the Excludes2 note (above) indicates that T33-T34 covers the frostbite codes, so we can go directly to those codes in the Tabular.

Looking under T33.0 Superficial frostbite of head, there is a subcategory at T33.01, Superficial frostbite of ear. Then underneath that, we see T33.011, Superficial frostbite of right ear and T33.012 for Superficial frostbite of left ear. There is a note under T33 that states, “The appropriate 7th character is to be added to each code from category T33.” In this case, it is an initial encounter (the patient is receiving active treatment), so “A” would need to be appended to each code, making them:

  • T33.011A, Superficial frostbite of right ear, initial encounter
  • T33.012A, Superficial frostbite of left ear, initial encounter

Acute alcohol intoxication

Acute alcohol intoxication can be found by looking in the Index under Alcohol, alcoholic, alcohol-induced/intoxication (acute) (without dependence), F10.129. We can verify this code In the Tabular as:

F10.129, Alcohol abuse with intoxication, unspecified

See the note that states, “Use additional code for blood alcohol level, if applicable (Y90.-).”

The provider did indicate the patient’s blood-alcohol level was 120 mg/100 ml, so we need to report for it.

Going directly to Y90.- in the Tabular, we can see that the correct code is:

Y90.6, Blood alcohol level of 120-199 mg/100 ml

You will see the note at Y90 that states, “Code first any associated alcohol-related disorders (F10)”. So that helps us with our sequencing. F10.129 is sequenced first, followed by Y90.6.


External cause of morbidity codes (V00-Y99) should never be sequenced as the first-listed or principal diagnosis, according to the ICD-10-CM Coding Guidelines. Therefore, Y90.6 and X31.XXXA are assigned as secondary codes.

Oh, and did I mention to always, always be sure to read the Excludes1 and 2 notes.

Read all the instructional notes, because everything means something.

Case #2

Patient is a 36-week gestational-age female newborn infant brought in today after being born outside of a shopping mall on a cold -11.2 °F (-24 °C) winter day in Deering, North Dakota. History showed no prenatal care had been given. The infant was found abandoned and gasping, with a heart rate of 50 beats/minute, and was immediately brought to the ER. She was noted to have bradycardia and apnea, with a rectal temperature of 82.22 °F (27.9 °C). Patient was diagnosed with severe hypothermia, and intubation and CPR were immediately performed.

The correct ICD-10-CM code is P80, Cold injury syndrome.

To locate the code in the ICD-10-CM Index, see Hypothermia (accidental), neonatal, severe (chronic) (Cold injury syndrome), P80.0. In the Tabular, this code can be verified as:

P80.0, Cold injury syndrome

Synonym: Severe and usually chronic hypothermia associated with a pink flushed appearance, edema, and neurological and biochemical abnormalities.

This code is located in Chapter 16 under the section named Conditions involving the integument and temperature regulation of newborn (P80-P83). Codes from this chapter are only for use on newborn records, never on maternal records. Other codes listed in this section are:

  • P80.8, Other hypothermia of newborn (mild hypothermia of newborn)
  • P80.9, Hypothermia of newborn, unspecified


We have discussed the ins and outs of accidental hypothermia and how to code for it. We have also talked about how to dress appropriately the next time you plan to be exposed to cold temperatures. And if a friend or loved one shows signs of hypothermia, you will know the necessary steps to take to keep them safe while waiting for paramedics to arrive. Fortunately, my Uncle Jim survived the condition without any problems, thanks to Julie’s help and the medical team’s care.

Just talking about hypothermia makes me cold. I think I’ll go turn up the heat.

Note: Hypothermia can be caused by cold water, getting cold in wet clothes, living in a cold home, and not having the appropriate dry clothing for protection.

Man in freezing cold water due to hypothermia and how to code for it in ICD-10-CM

I wrote this post and had it first published in BC Advantage/ under the title, “Baby, It’s Cold Outside and That Can Kill You.” It is reprinted here with permission. 

** This post has been updated to reflect the FY 2022 ICD-10-CM coding guidelines. **

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