Internal Medicine Coding Alert

Question: When should I use a diagnosis of malignant hypertension? For example, if a patient has a stroke and hypertension, should I report 401.0 or 401.1? What sort of language (other than the word "malignant") should I look for in the dictation for a patient with hypertension to determine if the condition qualifies as benign or malignant?

California Subscriber

Answer: Although 401.x (Essential hypertension) contains three fourth-digit subclassification options, many internal medicine coders use the same code: 401.1 (... benign). In fact, because 401.0 (... malignant) describes a life-deteriorating disease, you will rarely use that code.
  
In malignant hypertension, the patient's blood pressure rapidly and severely elevates. The high blood pressure causes severe damage that can result in organ failure and/or death if untreated. A patient in such debilitation would require hospitalization. Therefore, 401.0 normally applies to patients who are in an intensive care unit or an emergency room.
  
You should avoid using the third option, 401.9 (...  unspecified), whenever possible. Insurers may not cover unspecified diagnoses as readily as specific codes.