February 19, 2007

Coding for Pregnancy-Related Hypertension
For The Record
Vol. 19 No. 3 P. 32

Preeclampsia is defined as a patient experiencing elevated blood pressure with excess protein in the urine after 20 weeks of pregnancy. Also called toxemia, this condition typically occurs in the second half of pregnancy and can be classified as mild or severe. Mild or unspecified preeclampsia without mention of preexisting hypertension is classified to ICD-9-CM code 642.4x. Severe preeclampsia without mention of preexisting hypertension is assigned to code 642.5x. One of the following fifth-digit subclassifications is required to identify the episode of care:

• 0 – Unspecified as to episode of care or not applicable;

• 1 – Delivered, with or without mention of antepartum condition;

• 2 – Delivered, with mention of postpartum complication;

• 3 – Antepartum condition or complication; and

• 4 – Postpartum condition or complication.

The only real cure for preeclampsia is delivery.

Symptoms
The following are common signs and symptoms of preeclampsia:

• elevated blood pressure;

• proteinuria;

• severe headaches;

• changes in vision such as temporary loss of vision, blurred vision, or sensitivity to light;

• upper abdominal pain;

• unexplained anxiety;

• nausea or vomiting;

• dizziness;

• decreased urine output; and

• sudden weight gain (more than 2 pounds per week or 6 pounds per month).

Possible causes of preeclampsia include poor nutrition, high body fat, and insufficient blood flow to the uterus.

Diagnosis
Preeclampsia is most frequently diagnosed during a routine prenatal checkup. One abnormal blood pressure reading is not enough to confirm the diagnosis. Several abnormal readings need to be recorded before the physician will diagnose the condition. A normal blood pressure reading is typically less than 130/85 millimeters of mercury (mm/Hg). Therefore, 140/90 mmHg is above normal. Urine tests are also performed to check for the presence of excess protein.

Complications
If the preeclampsia cannot be controlled, the patient may develop HELLP syndrome or eclampsia. HELLP syndrome stands for hemolysis (the destruction of red blood cells), elevated liver enzymes, low platelet count and can cause liver failure and coagulation. HELLP syndrome is classified to code 642.5x.

Eclampsia is defined as preeclampsia plus seizures. It can permanently damage vital organs, cause brain damage, or cause the patient to slip into a coma. It can also result in death to either the mother or the baby. Eclampsia without mention of preexisting hypertension is classified to code 642.6x.

Gestational Hypertension
Gestational hypertension may be diagnosed when the patient experiences elevated blood pressure without proteinuria. The elevated blood pressure is mild and typically occurs in the later stages of pregnancy. Gestational hypertension can lead to preeclampsia. Assign code 642.3x for gestational hypertension. Code 642.3x also includes documentation of transient hypertension in pregnancy and pregnancy-induced hypertension.

Chronic Hypertension
Chronic hypertension is elevated blood pressure that appears before 20 weeks of pregnancy and lasts more than 12 weeks after delivery. This type of hypertension is not typically caused by pregnancy but may not be diagnosed until the hypertension doesn’t resolve after delivery. The appropriate code assignment for chronic hypertension in pregnancy depends on the type of hypertension. Code 642.0x includes the following diagnoses:

• benign essential hypertension in pregnancy;

• chronic hypertension in pregnancy;

• essential hypertension in pregnancy; and

• preexisting hypertension in pregnancy.

Code 642.1x includes hypertension secondary to renal disease complicating pregnancy. A code from category 405 will be assigned as a secondary diagnosis to identify the type of secondary hypertension present. An additional code may also be assigned to identify the type of renal failure present, if any.

The following diagnoses are included in code 642.2x:

• hypertensive heart and renal disease in pregnancy;

• hypertensive heart disease in pregnancy;

• hypertensive renal disease in pregnancy (Note: hypertension secondary to renal disease is assigned to code 642.1x); and

• malignant hypertension in pregnancy. (Note: benign or unspecified preexisting hypertension in pregnancy is classified to code 642.0x)

Additional codes may be assigned as secondary diagnoses to identify the specific type of hypertensive heart and/or renal disease (categories 402-404), chronic kidney disease (category 585), or heart failure (category 428), if present.

If a patient with preexisting hypertension develops preeclampsia or eclampsia during the current pregnancy, code 642.7x is assigned.

Code 642.9x is assigned if hypertension is documented during the current pregnancy, but it is not specified as transient/gestational or preexisting.

Coding and sequencing for pregnancy-related hypertension are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to nearly 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.

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