Pericarditis Coding Tips in ICD-10-CM

Pericarditis definition and diagram to help with pericarditis coding

Inflammation in the body is the body’s way of responding to an infection or injury. When an area of the body, such as the pericardium, becomes inflamed, it can lead to major diseases. Here you will learn facts about the disease, as well as pericarditis coding tips in ICD-10-CM.

What is Pericarditis?

Pericarditis is the most common disease process involving the pericardium and is defined as inflammation of the pericardium, otherwise referred to as the pericardial sac, according to the the National Center for Biotechnology Information. Pericarditis is usually acute, but it can also come and go for many years. It mostly appears in men, but anyone can be affected. 

Role of the Pericardium

The pericardium is made up of two thin layers that fill up with fluid and cover the outer area of the heart. The pericardium, although not critical for human survival, does serve some important functions: 

  • It keeps the heart fixed in place within the thoracic (chest) cavity. 
  • It forms as a barrier to the heart to prevent infection and malignancy that might spread from nearby organs like the lungs.
  • It lubricates the heart to prevent friction within the tissues around it as it beats.
  • It prevents the heart from stretching too much and overfilling with blood so the heart can function efficiently.


Chest pain is the most common symptom of pericarditis, according to the Mayo Clinic. The chest pain is usually sharp or stabbing, but in some people, it can feel more like an ache or pressure.  

  • It occurs when the irritated layers of the pericardium rub against each other.
  • It often comes on quickly and occurs in the middle or left side of the chest.
  • It may spread to the left shoulder and neck.
  • It often gets worse when coughing, taking deep breaths, or lying down.
  • It lessens when sitting up and leaning forward.

Other symptoms may include:

  • Fever
  • Cough
  • Swelling in the abdomen or legs
  • Fatigue or general feeling of weakness or being sick
  • Heart palpitations
  • Shortness of breath when lying down

The specific symptoms are dependent on the type of pericarditis diagnosed.

Pericarditis Types

Pericarditis can be classified, as it relates to time, into:

  • Acute pericarditis, lasting less than 3 weeks
  • Incessant pericarditis, lasting approximately 4-6 weeks but less than 3 months
  • Chronic pericarditis, lasting more than 3 months 
  • Recurrent pericarditis, an episode that occurs after being symptom free for 4-6 weeks


The exact cause of pericarditis cannot be established in most cases, and the diagnosis made is idiopathic acute pericarditis. When the cause is established, it is most often due to a viral infection. Bacterial infections and fungal organisms are less common causes. 

  • Viral infections include coxsackieviruses A and B, echoviruses, parvovirus B19, HIV, influenza, and multiple herpes viruses such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). 
  • Bacterial infections include tuberculosis, Coxiella burnetii, Meningococcus, Pneumococcus, Staphylococcus and Streptococcus.
  • Fungal organisms include Histoplasma, Coccidioides, Candida and Blastomyces or parasitic species such as Echinococcus, and Toxoplasma.

Non-infectious causes include:

  • Cancer (often secondary to metastatic disease)
  • Autoimmune disease such as systemic lupus erythematosus, rheumatoid arthritis, and Behcet’s disease
  • Metabolic causes such as uremia and myxedema
  • Trauma following an injury
  • Heart attack or heart surgery
  • Certain medications


Inflammation of the pericardium may also be associated with certain complications. They are:

  • Pericardial effusion. Excess fluid builds up between the pericardial layers. The appearance of the fluid may vary based on the cause.
  • Cardiac tamponade. Excess fluid buildup (pericardial effusion) that becomes too much or accumulates too quickly can compress the heart, leading to a decrease in cardiac output and shock. Without proper treatment, this condition can result in death.
  • Constrictive pericarditis. This is a pericardial thickening that rarely occurs months or years after the initial pericarditis has passed. It causes scar-like tissue to form throughout the sac that eventually becomes stiff. This scarred tissue begins to put pressure on the heart and keeps it from functioning correctly.
  • Effusive-constrictive pericarditis. Constrictive pericarditis coexists with pericardial effusion. The pericardial thickening occurs even after a pericardiocentesis is performed.


Diagnosing pericarditis can be difficult and is best left for a team of physicians that includes a cardiologist, radiologist, cardiac surgeon, infectious disease expert, primary care provider, and nurse practitioner. Since most patients will experience vague chest pain, the diagnosis may look like a heart attack, pleurisy, or angina.  

Patients with suspected acute pericarditis should have an ECG, echocardiogram, and chest X-ray done. Tests and procedures will be performed to determine if the patient had previously suffered a myocardial infarction (heart attack). If an infection is suspected, blood tests may be necessary. If another specific cause is suspected, more testing may be needed and would be performed according to the cause. 

Pericarditis Coding (ICD-10-CM)

Codes for pericarditis and its complications are located in Chapter 9. Diseases of the Circulatory System (I00-I99), Other forms of heart disease (I30-I52). Some of these codes require an additional code or multiple codes to report the patient’s condition.

Categories I30, I31, and I32 are broken down as:

I30, Acute pericarditis

I30.0, Acute nonspecific idiopathic pericarditis
I30.1, Infective pericarditis
I30.8, Other forms of acute pericarditis
I30.9, Acute pericarditis, unspecified

I31, Other diseases of pericardium

I31.0, Chronic adhesive pericarditis
I31.1, Chronic constrictive pericarditis
I31.2, Hemopericardium, not elsewhere classified
I31.3, Pericardial effusion (noninflammatory)
I31.4, Cardiac tamponade
I31.8, Other specified diseases of pericardium
I31.9, Disease of pericardium, unspecified

I32, Pericarditis in diseases classified elsewhere

Before selecting the correct code(s) from the categories above, be sure to review the list of Inclusive terms, along with Code First, Excludes1, and Excludes2  notes.

When reporting for I31.4, Cardiac tamponade, and I32, Pericarditis in diseases, the instructional note tells us that we must code first the underlying disease.

You will find that in some cases that a combination code is reported from Chapter 1. Certain Infectious and Parasitic Diseases rather than a code from Chapter 9. More on this will be discussed below in coding example #3.

When to Use Codes for Other and Unspecified?

  • Other. Assign I30.8, Other forms of acute pericarditis, and I31.8, Other specified diseases of pericardium, when the disease is documented in the record but is not found elsewhere in this section.
  • Unspecified. Assign I30.9, Acute pericarditis, unspecified, and I31.9, Disease of pericardium, unspecified, when the documentation does not provide enough information to assign a more definitive diagnosis in this section. 

Coding Examples

Let’s look at a few coding examples.

#1. Patient is diagnosed with staphylococcal pericarditis.

ICD-10-CM: I30.1, B95.8

In the Alphabetic Index, look up Pericarditis (with decompensation) (with effusion)/staphylococcal I30.1. Verified in the Tabular, I30.1 refers to Infective pericarditis. There is an instructional note at I30 that indicates we are to select a code (B95-B97) to identify the infectious agent.

When we go to B95-97 in the Tabular, we can see that B95.8,Unspecified staphylococcus as the cause of diseases classified elsewhere, is the correct code. This would be reported as a secondary code, because codes from categories B95-B97 are used as supplementary or additional codes to identify the infectious agent(s) in diseases classified elsewhere.

If we were to look up the correct code in the Index, we would go to Staphylococcus, staphylococcal/as cause of disease classified elsewhere B95.8. It can then be verified in the Tabular

#2. Patient with chronic inflammation of the pericardium with fibrous scarring is diagnosed with chronic constrictive pericarditis.

ICD-10-CM: I31.1

In the Index, look up Pericarditis (with decompensation) (with effusion)/constrictive (chronic) I31.1. Verifying this code in the Tabular, I31.1 refers to Chronic constrictive pericarditis.

#3. Pericarditis due to Coxsackie virus

ICD-10-CM: B33.23

Look up Pericarditis (with decompensation) (with effusion)/coxsackie B33.23. Verifying this code in the Tabular, B33.23 refers to Viral pericarditis.

As you can see, only one code is needed here and it comes from Chapter 1 rather than Chapter 9. It is a combination code that includes both the pericarditis and the infectious agent in the same code.

If you look at Chapter 9, category I32, Pericarditis in diseases classified elsewhere, you will also see why this code cannot be found in Chapter 9.

The instructional note at I32 states:

Excludes1: pericarditis (in):
coxsackie (virus) (B33.23)
gonococcal (A54.83)
meningococcal (A39.53)
rheumatoid (arthritis) (M05.31)
syphilitic (A52.06)
systemic lupus erythematosus (M32.12)
tuberculosis (A18.84)

An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note.

Pericardium and pericarditis and coding tips in ICD-10-CM

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