Coding Acute Conditions: Eliminate Chronic Concerns
Accurate ICD-10 coding requires proper documentation and an understanding of clinical conditions.
By Betty Hovey, CPC, CPC-H, CPB, CPMA, CPC-I, CPCD
Coding acute conditions in ICD-10-CM can be tricky for a few reasons: For starters, the term “acute” has various meanings in the diagnosis code set. Second, there are timeframe factors to consider. And, third, there’s a new concept of acute recurrent conditions. To help clear up any coding confusion you may have, first consider Merriam-Webster’s definition of acute:
(1): characterized by sharpness or severity, “acute pain” (2): having a sudden onset, sharp rise, and short course, “acute disease” (3): being, providing, or requiring short-term medical care (as for serious illness or traumatic injury) “acute hospitals” “an acute patient.”
Next, consider acute condition criteria and look at a few telling examples, as follows.
Myocardial Infarctions (MI)
Coronary arteries are a network of arteries that supply blood to the heart muscle. The left main coronary artery and the right coronary artery stem from the aorta. The left main coronary artery bifurcates into the left circumflex and left anterior descending arteries, supplying blood to the left ventricle. The right coronary artery branches into the right marginal artery and posterior descending artery, supplying blood to the right ventricle.
Coronary artery disease is the result of the accumulation of atheromatous plaque within the walls of the coronary arteries. If blood flow is blocked long enough, a portion of the heart muscle is damaged or dies. This is an MI, or heart attack. More than a million people in the United States each year suffer MIs. The site of the MI will reflect the coronary artery experiencing the ischemia. For example, an MI of the anterior wall is caused by ischemia in the left anterior descending coronary artery.
ST elevation myocardial infarction (STEMI) occurs when there is a transmural infarction of the myocardium, which means the entire thickness of the myocardium (endocardium, myocardium, and pericardium) has undergone necrosis. This results in ST elevation on an electrocardiogram (ECG).
Non-ST elevation myocardial infarction (NSTEMI) occurs when there is a partial dynamic block to coronary arteries. There will be no ST elevation or Q waves on the ECG because transmural infarction is not seen.
According to ICD-10-CM, an MI is considered acute (AMI) when it’s specified as acute or is stated to persist four weeks (28 days) or less from onset. In this case, acute is tied to the duration.
Example 1: A patient presents to the clinic. Per documentation, the patient is here for a hospital follow up for an MI of the left anterior descending artery.
Without MI timing information, you’ll need to query the provider to assign the correct ICD-10-CM code. From an ICD-10-CM standpoint, if the MI occurred within 28 days, it’s acute.
There are no codes for chronic symptomatic MI in ICD-10-CM. If the patient is still symptomatic after 28 days, the guidelines (I.C.9.e.1) state that the appropriate aftercare code should be assigned. It’s imperative for the physician or other provider to understand the importance of documenting the timeframe and for the coder to understand how to use that information for coding purposes.
Example 2: A patient presents to the clinic. Per documentation, the patient is here for hospital follow-up for an MI of the left anterior descending artery suffered 10 days prior. The patient is still symptomatic.
In this example, there is sufficient information to support assignment of code I21.02 ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery.
Congestive heart failure describes a condition in which the heart isn’t able to pump enough blood to meet a body’s needs. This may happen when the heart muscle is weaker than normal, or when there is a defect in the heart that prevents blood from circulating. When the heart doesn’t circulate blood normally, the kidneys receive less blood. The kidneys then filter less fluid out of circulation into urine. The extra fluid in circulation builds up in the lungs, the liver, around the eyes, and sometimes in the legs. This is called fluid “congestion;” thus, the condition “congestive heart failure.”
Heart failure can be systolic, diastolic, or combined systolic and diastolic:
- When the left ventricle can’t contract enough, it’s systolic heart failure.
- When the left ventricle can’t fill with enough blood, it’s diastolic heart failure.
Heart failure can also be acute, chronic, or acute on chronic. In this case, acute heart failure is heart failure that happens when there has been sudden damage to the heart—for example, due to an MI, thrombus in the heart, or severe infection. Acute heart failure is life threatening.
Chronic heart failure happens slowly and is typically due to an underlying condition, such as hypertension or heart disease. Acute on chronic is seen when a patient has chronic heart failure and suffers an acute exacerbation.
Example: A patient presents to the emergency department with no prior cardiac history and no chronic diseases. He is found to have suffered an AMI and to be in systolic heart failure due to the AMI.
In this case, the documentation stating that the heart failure is brought on by the sudden MI renders the diagnosis acute systolic heart failure, indicated by ICD-10-CM code I50.21 Acute systolic (congestive) heart failure.
Asthma is a chronic lung disease that inflames and narrows the airways. People with asthma experience symptoms when the airways tighten, inflame, or fill with mucus. According to the American Lung Association, asthma is one of the most common chronic disorders in childhood, with an estimated 7.1 million children under 18 years of age affected. It’s the leading cause of absenteeism from school.
Common asthma symptoms include:
- Coughing, especially at night
- Shortness of breath
- Chest tightness, pain, or pressure
Asthma is categorized by severity:
- Mild intermittent: The patient is symptomatic two or fewer days per week, awakens at night two times or fewer per month, uses a rescue inhaler two or fewer days per week, has no interference with normal activity, and has greater than 80 percent predicted lung functions and normal lung function between exacerbations.
- Mild persistent: The patient is symptomatic more than two days per week; awakens at night three to four times per month; uses a rescue inhaler more than two days per week, but not daily; has minor limitation with normal activity; and has greater than 80 percent predicted lung function.
- Moderate persistent: The patient is symptomatic daily; awakens at night more than once per week, but not nightly; uses a rescue inhaler daily; has some limitation with normal activity; and has 60-80 percent predicted lung functions.
- Severe persistent: The patient is symptomatic throughout the day; awakens nightly; uses a rescue inhaler several times per day; has extreme limitations with normal activity; and has less than 60 percent predicted lung functions.
Asthma is also categorized by complication:
- Without complications
- With acute exacerbation
- With status asthmaticus
According to ICD-10-CM guidelines (I.C.10.a.1), an acute exacerbation is a worsening or a decompensation of a chronic condition. An acute exacerbation is not equivalent to an infection superimposed on a chronic condition, although an exacerbation may be triggered by an infection. Status asthmaticus is an acute exacerbation of asthma that remains unresponsive to initial treatment with bronchodilators.
Example: An asthmatic patient presents for a check-up. The patient states that she uses her rescue inhaler daily; her asthma awakens her a few nights per week; and she has some limitations to normal activities. She has been coughing and running a fever. She is found to have pneumonia.
This case is not asthma in acute exacerbation, but moderate persistent asthma with pneumonia—a chronic condition with the pneumonia superimposed. There is no indication of a sudden worsening of the asthma itself.
It All Comes Down to Proper Documentation
It’s important to review these issues with your physicians and other providers to ensure documentation in the medical record supports the more specific code assignment possibilities in ICD-10-CM. You must also understand the differences in verbiage in ICD-10-CM to assign the correct codes. Working in cooperation with your peers will allow you to piece together the ICD-10-CM puzzle.