May 12, 2008

Coding for Acute Renal Failure
For The Record
Vol. 20 No. 10 P. 31

Acute renal failure is the sudden loss of kidney function that occurs when the kidneys stop filtering waste products such as urea from the blood, causing them to accumulate. Acute renal failure is defined a significant decrease (greater than 50%) in glomerular filtration rate over a period of hours to days, with an accompanying accumulation of nitrogenous wastes in the body. It may result from a drastic drop in blood pressure that prevents enough blood from reaching the kidneys, a blockage of the blood vessels leading to the kidneys, or an obstructed urine flow after it leaves the kidneys.

Signs and Symptoms
Symptoms of acute renal failure depend on the severity, rate of progression, and underlying cause. Common signs and symptoms include decreased urine output, increased creatinine level, increased blood urea nitrogen (BUN) level, a BUN to creatinine ratio greater than 20 (in prerenal failure), electrolyte imbalances (acidosis, hyperkalemia, hyponatremia), a skin rash, confusion, seizures, and coma.

Treatment
When a patient presents with acute renal failure, treatment is directed at the underlying cause. The physician will restrict water intake and modify the diet to include high carbohydrate, low protein, and low potassium. If the kidney failure is severe, dialysis will be necessary to remove excess waste products. In addition, if the kidneys were badly damaged, a transplant may be necessary.

Coding for Acute Renal Failure
Acute renal failure is classified to ICD-9-CM category 584. When a patient develops acute renal failure during a hospital stay, sequence a code from category 584 as a secondary diagnosis. If the patient is admitted with acute renal failure due to an underlying condition, the acute renal failure may be sequenced as the principal diagnosis with a code for the underlying condition sequenced as a secondary diagnosis.

For example, a patient is admitted with acute renal failure secondary to dehydration and treated appropriately with IV fluids. The rehydration corrected the acute renal failure and the patient did not require dialysis. Code 584.9 would be sequenced as the principal diagnosis with code 276.51 as a secondary diagnosis. “This would be consistent whether the acute renal failure was due to dehydration or another condition” (AHA Coding Clinic for ICD-9-CM, 2003, first quarter, page 22).

In most instances, the acute renal failure is the more significant problem, which occasions the hospital admission. Therefore, since the admission is for treatment of the acute renal failure and not the underlying cause, it should be sequenced as the principal diagnosis (AHA Coding Clinic for ICD-9-CM, 2002, third quarter, page 28).

Acute Renal Failure With Chronic Renal Failure
Occasionally, medical record documentation may state the patient was admitted with acute-on-chronic renal failure, meaning there was an exacerbation of the chronic status, which may have been indicated by a rise in the creatinine level. Another condition such as dehydration may have caused the exacerbation. In this case, it is appropriate to assign a code for both the acute renal failure (584.9) and chronic renal failure (585.9).

However, once a patient develops end-stage renal disease (ESRD) and goes on chronic dialysis, acute renal failure is no longer an option. Patients with ESRD have no remaining functioning nephrons. Certain conditions (eg, rhabdomyolysis, gastrointestinal bleeding) may cause significant increases in creatinine that require more frequent dialysis but do not constitute acute renal failure as the kidneys are essentially dead.

Fluid Overload With Renal Failure
Designation of the principal diagnosis for a patient admitted with fluid overload depends on what other conditions the patient has and the circumstances of admission. If the patient is admitted with fluid overload due to acute renal failure, sequence the acute renal failure (584.9) as the principal diagnosis. A patient with ESRD admitted with congestive heart failure (CHF) resulting from fluid overload due to noncompliance with dialysis has CHF (428.0) sequenced as the principal diagnosis (AHA Coding Clinic for ICD-9-CM, 1996, third quarter, page 9).

However, if the patient does not have CHF and is admitted with fluid overload due to noncompliance with dialysis and the patient has ESRD, sequence the fluid overload (276.6) as the principal diagnosis (AHA Coding Clinic for ICD-9-CM, 2006, fourth quarter, page 136). Fluid overload (276.6) may be sequenced as the principal diagnosis if the patient is admitted with fluid overload with no documented cause. However, it is appropriate to obtain further clarification from the physician of the underlying cause.

Coding and sequencing for acute renal failure 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.