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The clinical concepts for internal medicine guide includes common ICD-10 codes, clinical documentation tips and clinical scenarios.

ICD-10 Clinical Documentation Tips for Internal Medicine

  • Acute Myocardial Infarction (AMI)
  • Hypertension
  • Asthma
  • Underdosing
  • Diabetes Mellitus, Hypoglycemia and Hyperglycemia
  • Abdominal Pain and Tenderness

Specifying anatomical location and laterality required by ICD-10 is easier than you think.

This detail reflects how physicians and clinicians communicate and to what they pay attention.

It is a matter of ensuring the information is captured in your documentation.

In ICD-10-CM, there are three main categories of changes:

  • Definition Changes
  • Terminology Differences
  • Increased Specificity

For internal medicine the focus is on increased specificity. Over 1/3 of the expansion of ICD-10 codes is due to the addition of laterality (left, right, or bilateral). Physicians and other clinicians likely already note laterality when evaluating the clinically pertinent anatomical site(s).


Definition Change

When documenting an AMI, include the following:

  1. Timeframe An AMI is now considered “acute” for 4 weeks from the time of the incident.
  2. Episode of care ICD-10 does not capture episode of care (e.g. initial, subsequent, sequelae).
  3. Subsequent AMI ICD-10 allows coding of a new MI that occurs during the 4 week “acute period” of the original AMI.

ICD-10 Code Examples

I21.02 ST elevation (STEMI) myocardial infarction involving left anterior descending coronary artery
I21.4 Non-ST elevation (NSTEMI) myocardial infarction
I22.1 Subsequent ST elevation (STEMI) myocardial infarction


Definition Change

In ICD-10, hypertension is defined as essential (primary). The concept of “benign or malignant” as it relates to hypertension no longer exists.

When documenting hypertension, include the following:

  1. Type e.g. essential, secondary, etc.
  2. Causal relationship e.g. Renal, pulmonary, etc.

ICD-10 Code Examples

I10 Essential (primary) hypertension
I11.9 Hypertensive heart disease without heart failure
I15.0 Renovascular hypertension


Terminology Difference

ICD-10 terminology used to describe asthma has been updated to reflect the current clinical classification system.

When documenting asthma, include the following:

  1. Cause Exercise induced, cough variant, related to smoking, chemical or particulate cause, occupational
  2. Severity Choose one of the three options below for persistent asthma patients
  • Mild persistent
  • Moderate persistent
  • Severe persistent
  1. Temporal Factors Acute, chronic, intermittent, persistent, status asthmaticus, acute exacerbation

ICD-10 Code Examples

J45.30 Mild persistent asthma, uncomplicated
J45.991 Cough variant asthma


Terminology Difference

Underdosing is an important new concept and term in ICD-10. It allows you to identify when a patient is taking less of a medication than is prescribed.

When documenting underdosing, include the following:

  1. Intentional, Unintentional,Non-compliance Is the underdosing deliberate? (e.g., patient refusal)
  2. Reason Why is the patient not taking the medication? ( hardship, age-related debility)

ICD-10 Code Examples

Z91.120 Patient’s intentional underdosing of medication regimen due to financial hardship
T36.4x6A Underdosing of tetracyclines, initial encounter
T45.526D Underdosing of antithrombotic drugs, subsequent encounter


Increased Specificity

The diabetes mellitus codes are combination codes that include the type of diabetes mellitus, the body system affected, and the complications affecting that body system.
When documenting diabetes, include the following:

  1. Type e.g. Type 1 or Type 2 disease, drug or chemical induces, due to underlying condition, gestational

  2. Complications What (if any) other body systems are affected by the diabetes condition? e.g. Foot ulcer related to diabetes mellitus

  3. Treatment Is the patient on insulin?

A second important change is the concept of “hypoglycemia” and “hyperglycemia.” It is now possible to document and code for these conditions without using “diabetes mellitus.” You can also specify if the condition is due to a procedure or other cause. The final important change is that the concept of “secondary diabetes mellitus” is no longer used; instead, there are specific secondary options.

ICD-10 Code Examples

E08.65 Diabetes mellitus due to underlying condition with hyperglycemia
E09.01 Drug or chemical induced diabetes mellitus with hyperosmolarity with coma
R73.9 Transient post-procedural hyperglycemia
R79.9 Hyperglycemia, unspecified


Increased Specificity

When documenting abdominal pain, include the following:

  1. Location e.g. Generalized, Right upper quadrant, periumbilical, etc.
  2. Pain or tenderness type e.g. Colic, tenderness, rebound

ICD-10 Code Examples

R10.31 Right lower quadrant pain
R10.32 Left lower quadrant pain
R10.33 Periumbilical pain