Internal Medicine Coding Alert

Reader Question:

Symptoms of Hypertension

Question: What symptoms qualify as malignant hypertension? Are there specific diastolic/systolic readings? What are the appropriate diagnosis codes?

North Carolina Subscriber
 
Answer: Malignant hypertension is a severe form of acute hypertension that results from an abrupt rise in blood pressure. If left untreated, malignant hypertension can damage the blood vessels in the eyes, kidneys, brain and heart. Diastolic pressures as high as 130 mmHg or more are commonly present. There is often a prior history of hypertension, especially hypertension resulting from kidney disorders.
 
Malignant hypertension also occurs in women with toxemia of pregnancy and people with renal vascular disorders. A higher risk of malignant hypertension exists in persons with a history of acute renal failure or renal hypertension caused by renal artery stenosis. A rapid increase in blood pressure suddenly occurs for no apparent reason.
 
Malignant hypertension can cause severe, permanent or life-threatening consequences from pressure damage to multiple organs of the body. These organs can include the brain, eyes, blood vessels, heart and kidneys. Acute renal failure may result from the damage to the blood vessels of the kidneys due to the high blood pressure.
 
Some symptoms of malignant hypertension are blurred vision, headache, change in mental status, chest pain, shortness of breath, cough, decreased urinary output, nausea and vomiting, seizure, weakness in extremities or numbness of extremities.
 
The key to correct coding for hypertension is not in establishing a clear clinical definition of malignant hypertension but in educating the physicians that -- for reporting purposes -- they must follow ICD-9's definition of malignant, regardless of the clinical definition. According to ICD-9 2001, malignant hypertension is "a severe form of hypertension, wherein the patient's blood pressure reading is consistently higher than 120 diastolic and is difficult to treat."
 
The codes for malignant hypertension are:
 
  • 402.0 -- hypertensive heart disease, malignant (severe high arterial blood pressure causing heart malfunctions)
     
  • 402.00 -- ... without congestive heart failure
     
  • 402.01 -- ... with congestive heart failure
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    If a specified heart condition (428.0-428.9, heart failure; 429.0-429.3, ill-defined descriptions and complications of heart disease such as myocarditis, myocardial degeneration, unspecified cardiovascular disease, and cardiomegaly; and 429.8-429.9, other ill-defined heart diseases) coexists with hypertension, but a cause-and-effect relationship does not exist or has not been adequately documented, apply two codes: one for the hypertension and one for the heart condition.
     
    When coding hypertensive cerebrovascular disease, two codes are necessary to describe the condition fully. Assign the first code from the 430-438 series (cerebrovascular disease) and the appropriate hypertension code (401-405).