Diabetes (codes E08 – E13) has greatly expanded in ICD-10. Physicians must document whether the diabetes is Type 1, Type 2, drug- or chemical induced, or due to an underlying condition. They must document the specific underlying condition, the specific drug or toxin, as well as the use of any insulin (Z79.4). ICD-10 requires very specific details regarding any complications or manifestation of the diabetes. For example, code E08.341 denotes diabetes mellitus due to underlying condition with severe non-proliferative diabetic retinopathy with macular edema. Physicians should use as many codes as necessary to fully describe all complications or manifestations.
ICD-10 code I10 denotes essential (primary) hypertension. This is a new definition in ICD-10. The concept of “benign or malignant,” as it relates to hypertension no longer exists. There are separate codes for hypertension involving vessels of the brain (codes I60 – I69) and hypertension involving vessels of the eye (code H35.0). ICD-10 also includes codes for hypertensive heart disease with or without heart failure (code I11) and hypertensive chronic kidney disease (code I12). It is important to note that physicians must document the stage of the chronic kidney disease as well. Additionally, there are codes for hypertensive heart and chronic kidney disease (code I13), as well as secondary hypertension (code I15). When reporting secondary hypertension, you must also code the underlying condition.
Asthma (code J45) is another diagnosis that was expanded in ICD-10. The National Heart, Lung, and Blood Institute (NHLB) uses asthma severity classification scale to account for the progressive nature of asthma. Physicians must document whether the asthma is:
- Mild intermittent (intermittent =less than or equal to two occurrences per week)
- Mild persistent (more than two times per week)
- Moderate persistent (daily and may restrict physical activity)
- Severe persistent (throughout the day with frequent severe attacks limiting the ability to breathe)
- Other and unspecified asthma
The physician must also specify whether the asthma is uncomplicated, with acute exacerbation, or with status asthmaticus. ICD-10 instructs the physician to identify tobacco exposure as an additional code when reporting asthma. Those choices are:
- Exposure to environmental tobacco smoke (Z77.22)
- Exposure to tobacco smoke in the perinatal period (P96.81)
- History of tobacco use (Z87.31)
- Occupational exposure to environmental tobacco smoke (Z57.31)
- Tobacco dependence (F17.-)
- Tobacco use (Z72.0)
ICD-10 includes various codes to denote specific forms of a middle ear infection. These codes are grouped in categories H65- H67 and distinguish between these forms of otitis media:
- Tubotympanic suppurative
- Atticoantral suppurative
Physicians must also document the following for many of the codes in this section:
- Acute vs. chronic
- Laterality (left vs. right vs. bilateral)
- Any associated perforated tympanic membrane
Tobacco exposure should be identified as a second diagnosis, using an additional code when an ear infection is reported.
ICD-10 includes a variety of new codes for reporting headaches. For example, when a patient presents with a migraine (code G43), physicians must specify whether it’s common, hemiplegic, persistent, chronic, ophthalmologic, abdominal, or menstrual. Cluster headaches and other trigeminal autonomic cephalalgias (code G44.0) are grouped into episodic, chronic, episodic paroxysmal hemicranias, chronic paroxysmal hemicranias, and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing. There are also codes for vascular headaches (G44.1), tension-type headaches (G44.2), post traumatic headaches (G44.3), drug-induced headaches (G44.4), as well as a variety of other headache syndromes. Many of the codes in the headache section also require the following documentation:
- With or without aura
- Intractable vs. not intractable
- With or without status migrainosus
The codes in Chapter 5 of ICD-10 (mental, behavioral, and neurodevelopmental disorders) parallel the codes in DSM-IV TR in most cases. According to the Centers for Disease Control and Prevention, an estimated 1 in 10 adults report depression, and patients often come to their primary-care physician for this condition. Depression codes have been greatly expanded in ICD-10. When a patient presents with major depression (codes F32 – F33), physicians must consider and document the following:
- Single episode vs. recurrent
- Mild, moderate, or severe
- With or without psychotic features
- In partial or full remission
Chapter 21 of ICD-10 includes an array of codes related to factors that influence health status and contact with health services. For example, primary-care physicians may interested in codes Z55- Z65, which pertain to health hazards related to socioeconomic and psychosocial circumstances, such as problems related to education and literacy, employment and unemployment, and occupation exposure to risk factors, among others. Codes in the Z68 category denote specific data related to body mass index (BMI). These should be reported additionally when reporting obesity (code E66) and the BMI is known. Codes in the Z72 category denote problems related to lifestyle (e.g., tobacco use, lack of exercise, and high-risk sexual behavior). This chapter also includes codes for preventive care, such as Z01.3 (encounter for examination of blood pressure), Z01.4 (encounter for gynecological exam), and more. Many of the codes for reporting well-visits require a selection between “with abnormal findings” or “without abnormal findings.” When abnormal findings are present, a second code is required to identity the abnormal findings.