Version 2024

2024 ICD-10-CM Diagnosis Code D81.5

Purine nucleoside phosphorylase [PNP] deficiency

ICD-10-CM Code:: D81.5
ICD-10 Code for:: Purine nucleoside phosphorylase [PNP] deficiency
Is Billable?: Yes - Valid for Submission
Chronic Condition Indicator: ^[1]: Chronic
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Code Information
Approximate Synonyms
Clinical Classification
Tabular List of Diseases and Injuries
Index to Diseases and Injuries References
Convert to ICD-9 Code
Patient Education
Other Codes Used Similar Conditions
Code History

Code Classification

Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
(D50–D89)
- Certain disorders involving the immune mechanism
  (D80-D89)
  - Combined immunodeficiencies
    (D81)

D81.5 is a billable diagnosis code used to specify a medical diagnosis of purine nucleoside phosphorylase [pnp] deficiency. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Purine-nucleoside phosphorylase deficiency

Clinical Classification

Clinical Category	CCSR Category Code	Inpatient Default CCSR	Outpatient Default CCSR
Immunity disorders	BLD008	Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.	Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Other specified and unspecified nutritional and metabolic disorders	END016	N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.	N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.

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).

- Deficiency, deficient
- - purine nucleoside phosphorylase (PNP) - D81.5

Convert D81.5 to ICD-9-CM

ICD-9-CM Code: 277.2 - Purine/pyrimid dis NEC
Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education

Immune System and Disorders

What is the immune system?

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

When germs such as bacteria or viruses invade your body, they attack and multiply. This is called an infection. The infection causes the disease that makes you sick. Your immune system protects you from the disease by fighting off the germs.

What are the parts of the immune system?

The immune system has many different parts, including:

Your skin, which can help prevent germs from getting into the body
Mucous membranes, which are the moist, inner linings of some organs and body cavities. They make mucus and other substances which can trap and fight germs.
White blood cells, which fight germs
Organs and tissues of the lymph system, such as the thymus, spleen, tonsils, lymph nodes, lymph vessels, and bone marrow. They produce, store, and carry white blood cells.

How does the immune system work?

Your immune system defends your body against substances it sees as harmful or foreign. These substances are called antigens. They may be germs such as bacteria and viruses. They might be chemicals or toxins. They could also be cells that are damaged from things like cancer or sunburn.

When your immune system recognizes an antigen, it attacks it. This is called an immune response. Part of this response is to make antibodies. Antibodies are proteins that work to attack, weaken, and destroy antigens. Your body also makes other cells to fight the antigen.

Afterwards, your immune system remembers the antigen. If it sees the antigen again, it can recognize it. It will quickly send out the right antibodies, so in most cases, you don't get sick. This protection against a certain disease is called immunity.

What are the types of immunity?

There are three different types of immunity:

Innate immunity is the protection that you are born with. It is your body's first line of defense. It includes barriers such as the skin and mucous membranes. They keep harmful substances from entering the body. It also includes some cells and chemicals which can attack foreign substances.
Active immunity, also called adaptive immunity, develops when you are infected with or vaccinated against a foreign substance. Active immunity is usually long-lasting. For many diseases, it can last your entire life.
Passive immunity happens when you receive antibodies to a disease instead of making them through your own immune system. For example, newborn babies have antibodies from their mothers. People can also get passive immunity through blood products that contain antibodies. This kind of immunity gives you protection right away. But it only lasts a few weeks or months.

What can go wrong with the immune system?

Sometimes a person may have an immune response even though there is no real threat. This can lead to problems such as allergies, asthma, and autoimmune diseases. If you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake.

Other immune system problems happen when your immune system does not work correctly. These problems include immunodeficiency diseases. If you have an immunodeficiency disease, you get sick more often. Your infections may last longer and can be more serious and harder to treat. They are often genetic disorders.

There are other diseases that can affect your immune system. For example, HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems. They get an increasing number of severe illnesses.

[Learn More in MedlinePlus]

Purine nucleoside phosphorylase deficiency

Purine nucleoside phosphorylase deficiency is a disorder of the immune system called an immunodeficiency. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria and viruses.

People with purine nucleoside phosphorylase deficiency have low numbers of immune system cells called T cells, which normally recognize and attack foreign invaders to prevent infection. Some affected individuals also have low numbers of other immune system cells called B cells, which normally help fight infections by producing immune proteins called antibodies (or immunoglobulins). These proteins target foreign invaders and mark them for destruction. The most severely affected individuals, who lack T cells and B cells, have a serious condition called severe combined immunodeficiency (SCID).

The shortage of immune system cells in people with purine nucleoside phosphorylase deficiency results in repeated and persistent infections typically beginning in infancy or early childhood. Infections most commonly affect the sinuses and lungs. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. The infections can be very serious or life-threatening, and without successful treatment to restore immune function, children with purine nucleoside phosphorylase deficiency usually do not survive past childhood.

Infants with purine nucleoside phosphorylase deficiency typically grow more slowly than healthy babies. About two-thirds of individuals with this condition also have neurological problems, which may include developmental delay, intellectual disability, difficulty with balance and coordination (ataxia), and muscle stiffness (spasticity). People with purine nucleoside phosphorylase deficiency are also at increased risk of developing autoimmune disorders, which occur when the immune system malfunctions and attacks the body's tissues and organs.