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2025 ICD-10-CM Diagnosis Code F05

Delirium due to known physiological condition

ICD-10-CM Code:
F05
ICD-10 Code for:
Delirium due to known physiological condition
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

F05 is a billable diagnosis code used to specify a medical diagnosis of delirium due to known physiological condition. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

This code describes a circumstance which influences the patient's health status but not a current illness or injury. The code is unacceptable as a principal diagnosis.

Code Classification

  • Mental and behavioural disorders
    F01–F99
    • Mental disorders due to known physiological conditions
      F01-F09
      • Delirium due to known physiological condition
        F05

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Acute confusional state, of endocrine origin
  • Acute confusional state, of infective origin
  • Acute confusional state, of metabolic origin
  • Acute confusional state, post-traumatic
  • Delirium due to hepatic encephalopathy
  • Delirium of mixed origin
  • Hyperactive behavior
  • Hyperactive behavior
  • Hyperactive postoperative delirium
  • Hypoactive postoperative delirium
  • Mixed hyperactive hypoactive postoperative delirium
  • Post-injection delirium sedation syndrome
  • Postoperative confusion
  • Postoperative confusion
  • Postoperative confusion
  • Postoperative confusion
  • Postoperative delirium
  • Postseizure confusion
  • Postseizure delirium
  • Senile dementia with delirium
  • Sundowning
  • Toxic confusional state

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Neurocognitive disorders

CCSR Code: NVS011

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Acute or subacute brain syndrome
  • Acute or subacute confusional state (nonalcoholic)
  • Acute or subacute infective psychosis
  • Acute or subacute organic reaction
  • Acute or subacute psycho-organic syndrome
  • Delirium of mixed etiology
  • Delirium superimposed on dementia
  • Sundowning

Code First

Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
  • the underlying physiological condition, such as:
  • dementia F03.9

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Type 2 Excludes

Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Code Edits

The Medicare Code Editor (MCE) detects errors and inconsistencies in ICD-10-CM diagnosis coding that can affect Medicare claim validity. These Medicare code edits help medical coders and billing professionals determine when a diagnosis code is not appropriate as a principal diagnosis, does not meet coverage criteria. Use this list to verify whether a code is valid for Medicare billing and to avoid claim rejections or denials due to diagnosis coding issues.

Unacceptable principal diagnosis

There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

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Convert F05 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Delirium d/t other cond

ICD-9-CM: 293.0

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

View Conversion

Subacute delirium

ICD-9-CM: 293.1

Approximate Flag - The approximate mapping means this ICD-10 code does not have an exact ICD-9 equivalent. The matched code is the closest available option, but it may not fully capture the original diagnosis or clinical intent.

View Conversion

Patient Education


Delirium

What is delirium?

Delirium is a mental state in which you are confused, disoriented, and not able to think or remember clearly. It usually starts suddenly. It is often temporary and treatable.

There are three types of delirium:

  • Hypoactive, when you are not active and seem sleepy, tired, or depressed
  • Hyperactive, when you are restless or agitated
  • Mixed, when you change back and forth between being hypoactive and hyperactive

What causes delirium?

There are many different problems that can cause delirium. Some of the more common causes include:

  • Advanced cancer.
  • Alcohol or drugs, either from intoxication or withdrawal. This includes a serious type of alcohol withdrawal syndrome called delirium tremens. It usually happens to people who stop drinking after years of alcohol use disorder (AUD).
  • Dehydration and electrolyte imbalances.
  • Dementia.
  • Hospitalization, especially in intensive care.
  • Infections, such as urinary tract infections, pneumonia, and the flu.
  • Medicines. This could be a side effect of a medicine, such as sedatives or opioids. Or it could be from withdrawal after stopping a medicine.
  • Metabolic disorders.
  • Organ failure, such as kidney or liver failure.
  • Poisoning.
  • Serious illnesses.
  • Severe pain.
  • Sleep deprivation.
  • Surgeries, including reactions to anesthesia.

Who is more likely to get delirium?

Certain factors put you at risk for delirium, including:

  • Being in a hospital or nursing home
  • Having dementia
  • Having a serious illness or more than one illness
  • Having an infection
  • Older age
  • Having surgery
  • Taking medicines that affect the mind or behavior
  • Taking high doses of pain medicines, such as opioids

What are the symptoms of delirium?

The symptoms of delirium usually start suddenly, over a few hours or a few days. They often come and go. The most common symptoms include:

  • Changes in alertness (usually more alert in the morning, less at night)
  • Changing levels of consciousness
  • Confusion
  • Disorganized thinking, talking in a way that doesn't make sense
  • Disrupted sleep patterns, sleepiness
  • Emotional changes: anger, agitation, depression, irritability, overexcitement
  • Hallucinations and delusions
  • Memory problems, especially with short-term memory
  • Trouble concentrating

How is delirium diagnosed?

Your health care provider may use many tools to make a diagnosis:

  • A medical history, which includes asking about your symptoms
  • Physical and neurological exams
  • Mental status testing, which checks for problems with your thinking and alertness
  • Lab and diagnostic imaging tests

Delirium and dementia have similar symptoms, so it can be hard to tell them apart. You can also have both at the same time. The differences between them are that:

  • Delirium starts suddenly and can cause hallucinations. It is mainly a problem with attention and staying alert. The symptoms may get better or worse and can last for hours or weeks.
  • Dementia develops slowly and does not cause hallucinations. It usually starts with memory loss. The symptoms don't change often, like they can with delirium. Dementia almost never gets better.

What are the treatments for delirium?

Treatment of delirium focuses on the causes and symptoms of delirium. The first step is to identify the cause. Often, treating the cause will lead to a full recovery. The recovery may take some time - weeks or sometimes even months. In the meantime, there may be treatments to manage the symptoms, such as:

  • Controlling the environment, which includes making sure that the room is quiet and well-lit, having clocks or calendars in view, and having family members around
  • Medicines, including those that control aggression or agitation and pain relievers if there is pain
  • If needed, making sure that the person has a hearing aid, glasses, or other devices for communication

Can delirium be prevented?

Treating the conditions that can cause delirium may reduce the risk of getting it. Hospitals can help lower the risk of delirium by avoiding sedatives and making sure that hospital rooms are kept quiet, calm, and well-lit. It can also help to have family members around and to have the same staff members treat the person each day (if possible).


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.