Internal Medicine Coding Alert

Question: The internist meets an established patient at the hospital who is in a hypoglycemic coma; the patient was admitted to the hospital the previous day. The internist performs a level-three hospital care service. How should I select an ICD-9 code for this encounter?

Nebraska Subscriber

Answer: It depends on if the patient is in a diabetic hypoglycemic coma, or is in a hypoglycemic coma.

According to the ICD-9 definition of diabetic hypoglycemic coma, the condition is "caused by hyperglycemia or hypoglycemia as complications of diabetes." This condition is also known as "diabetic coma (with ketoacidosis)," "diabetic hypoglycemic coma" and "insulin coma NOS."

So if the diabetes caused the patient's condition, you would report the following:

• 99233 (Subsequent hospital care, per day, for the evaluation and management of a patient, which requires at least two of these three key components: a detailed interval history; a detailed examination; medical decision making of high complexity) for the hospital care

• 250.3X (Diabetes with other coma) appended to 99233 to represent the patient's condition.

If, however, the patient is in a hypoglycemic coma without diabetes, diagnosis coding will change. According to ICD-9, a hypoglycemic coma is "induced by low blood sugar in non-diabetic patient." This condition is also known as "iatrogenic hyperinsulinism" or "non-diabetic insulin coma."

So if the patient's coma was not caused by diabetes, you would report 99233 for the hospital care, with 251.0 (Hypoglycemic coma) appended to describe the patient's coma. Also, if the coma was drug-induced, include the appropriate E code, such as E930-E949 (Drugs, medicinal and biological substances causing adverse effects in therapeutic use ...).