Coding for Heatstroke and SIRS

person lying on the floor due to heatstroke with a bottle of liquid next to him. This image goes along with coding for heatstroke with SIRS.

*This post has been updated to reflect the coding guidelines for FY 2023.*

The Coding Challenge


A 29-year-old male is admitted for treatment of heatstroke after playing volleyball on the beach for many hours. The final diagnosis is heatstroke and SIRS with acute kidney failure. Assign for ICD-10-CM.

A. R65.11, T67.01XA, N18.9
B. T67.01XA, A41.9, N17.8
C. R65.10, N17.9, T67.01XA
D. T67.01XA, R65.11, N17.9


D. T67.01XA, R65.11, N17.9

The diagnoses are specified as heatstroke and SIRS with acute kidney failure. SIRS stands for systemic inflammatory response syndrome. Heatstroke is a serious matter that can lead to SIRS and organ dysfunction. It can even be fatal. You can learn more about this at the bottom of this post.

Locate and Verify

Heatstroke (T67.01-)

To locate heatstroke in the ICD-10-CM coding manual, look up Heat (effects)/stroke T67.01. When we go to this code in the Tabular, we can see that there is a 7th character required for T67.01 to indicate the episode of care. The patient is receiving active treatment and is being seen for an initial encounter. Therefore, we should assign T67.01XA (Heatstroke and sunstroke, initial encounter).

According to the ICD-10-CM Official Guidelines for Coding and Reporting:

“7th character “A,” initial encounter is used for each encounter where the patient is receiving active treatment for the condition. 7th character “D” subsequent encounter is used for encounters after the patient has completed active treatment of the condition and is receiving routine care for the condition during the healing or recovery phase. 7th character “S,” sequela, is for use for complications or conditions that arise as a direct result of a condition, such as scar formation after a burn. The scars are sequelae of the burn.”

ICD-10-CM codes for heatstroke and sunstroke including T67.01XA, T67.01XD, and T67.01XS.

Inclusion terms listed under T67.01 (Heatstroke and sunstroke) are:

  • Heat apoplexy
  • Heat pyrexia
  • Siriasis
  • Thermoplegia

There is also a “use additional” note indicating that we need to assign a code to identify any associated complications of heatstroke, such as:

  • coma and stupor (R40.-)
  • rhabdomyolysis (M62.82)
  • systemic inflammatory response syndrome (R65.1-)

Note that systemic inflammatory response syndrome, or SIRS, is one of the diagnoses provided in this coding scenario.

SIRS (R65.1-)

Looking up R65.1- in the Tabular, there are two codes listed, which include:

  • R65.10 SIRS of non-infectious origin without acute organ dysfunction
  • R65.11 SIRS of non-infectious origin with acute organ dysfunction

The correct code is:

R65.11, Systemic inflammatory response syndrome (SIRS) of non-infectious origin with acute organ dysfunction

A “Use additional” note instructs the coder to code to identify specific acute organ dysfunction, such as:

  • acute kidney failure (N17.-)
  • acute respiratory failure (J96.0-)
  • critical illness myopathy (G72.81)
  • critical illness polyneuropathy (G62.81)
  • disseminated intravascular coagulopathy [DIC]
  • encephalopathy (metabolic) (septic) (G93.41)
  • hepatic failure (K72.0-)

The documentation provides a diagnosis of acute kidney failure, which is acute organ dysfunction. The coder should go to N17.- in the Tabular.

Acute Kidney Failure (N17.-)

The note at R65.11 instructs us to to N17.- in the Tabular. When looking at our code options there, we can see the correct code is:

N17.9 – Acute kidney failure, unspecified
Acute kidney injury (nontraumatic)

A note at N17 states, “Code Also” associated underying condition.

There is a guideline that helps us with sequencing of these codes:

According to the ICD-10-CM coding guidelines, “When SIRS is documented with a noninfectious condition, and no subsequent infection is documented, the code for the underlying condition, such as an injury, should be assigned, followed by code R65.10, Systemic inflammatory response syndrome (SIRS) of non-infectious origin without acute organ dysfunction, or code R65.11, Systemic inflammatory response syndrome
(SIRS) of non-infectious origin with acute organ dysfunction. If an associated
acute organ dysfunction is documented, the appropriate code(s) for the specific
type of organ dysfunction(s) should be assigned in addition to code R65.11.”

The underlying condition is heartstroke (T67.01XA), so it is sequenced first, followed by R65.10 for SIRS, and then N17.9 for the organ dysfunction or kidney failure.

The correct answer is D. T67.01XA, R65.11, N17.9

Incorrect Answers

A, B, and C are incorrect.

A. R65.11, T67.0XXA, N18.9. The sequencing is incorrect (as explained above), and N18.9 refers to Chronic kidney disease, unspecified.

B. T67.0XXA, A41.9, N17.8. A41.9 refers to Sepsis, unspecified organism, and N17.8 describes Other acute kidney failure.

C. R65.10, N17.9, T67.01XA. Incorrect sequencing and R65.10 refers to Systemic inflammatory response syndrome (SIRS) of non-infectious origin without acute organ dysfunction. Remember to read all instructional notes, including Excludes1, Excludes2, code first, and use additional, before assigning the appropriate code(s).

How Did You Do?

If you aced the coding challenge, I’m impressed! Yay!! Yippee!! Congratulations!

No worries if you were on the right track but got confused at some point. Keep working on it until you can do it without missing a beat.

“Successful men and women keep moving. They make mistakes, but they don’t quit.” – Conrad Hilton

About These Conditions


Heatstroke is the most severe type of heat injury and is described as a body temperature higher than 104°F, which is associated with neurologic dysfunction (according to Medscape). It is considered a medical emergency and can start as heat stress and progress to heatstroke, systemic inflammatory response syndrome (SIRS), multi-organ dysfunction syndrome (MODS), and can even lead to death.

The signs and symptoms of heatstroke, as reported by WebMD, include:

  • A body temperature elevated above 104°F
  • Dehydration
  • Throbbing headache
  • Dizziness and light-headedness
  • Lack of sweating despite the heat
  • Red, hot, and dry skin
  • Muscle weakness or cramps
  • Nausea and vomiting
  • Rapid heartbeat, which may be either strong or weak
  • Rapid, shallow breathing
  • Behavioral changes such as confusion, disorientation, or staggering
  • Seizures
  • Unconsciousness

Systemic Inflammatory Response Syndrome (SIRS)

SIRS is generally related to infection, but when it is caused by a non-infectious problem such as heatstroke, Medscape reports that it is characterized by two or more of the following conditions:

  • Fever of more than 100.4°F or less than 96.8°F (hypothermia)
  • Heart rate of more than 90 beats per minute (tachycardia)
  • Respiratory rate of more than 20 breaths per minute or arterial carbon dioxide tension (PaCO2) or less than 32 mm Hg (tachypnea)
  • Abnormal white blood cell count (>12,000/µL or < 4,000/µL or >10% immature [band] forms) (leukocytosis)

SIRS due to an infection is reported with Sepsis codes.

Acute Kidney Failure

Acute kidney failure is a condition that develops quickly when the kidneys cannot filter waste from the blood.

Tips For Taking a Timed Exam

When taking a timed exam, we don’t have much time to look up each code in the Index. Therefore, you may want to consider some shortcuts to finding the best answer in the given amount of time.

For example, in the above coding scenario, I would go about it this way:

  1. Look at the answers first.
  2. All four answers include T67.0XXA, but this code is not sequenced in the same order in every answer. So, I would look up that code in the Tabular and review any instructional notes.
  3. The instructional notes at T67.0 tell us that the underlying condition (heatstroke) should be sequenced first, followed by the complication (SIRS). This is evident by the “use additional “note.
  4. Going to R65.1-, we can see that R65.11 is the correct code. There is also a “code first” note at R65.1 to indicate T67.0 comes before R65.11.
  5. So we have our first two codes: T67.0XXA, R65.11.
  6. That immediately eliminates A, B, and C, leaving us only with D.
  7. I would not even bother to look up the code for acute kidney failure on a timed exam because the instructional note at R65.11 indicates that acute kidney failure is coded to N17.-.

Time is of the essence and can make all the difference between passing and failing. You don’t want to spend too much time on each question. Answer it, move on, and return to it later if time permits. Taking a timed exam is not like everyday coding.

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