Pyelonephritis, a kidney infection, can be a cause for concern. If you’re a healthcare professional or simply curious about medical coding, understanding the relevant ICD-10 codes is essential. This post will decipher the different ICD-10 codes associated with pyelonephritis, including unspecified, chronic, acute with UTI, laterality (side), sepsis association, pregnancy, and more.

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Understanding ICD-10 Codes: Pyelonephritis ICD-10

ICD-10 stands for International Classification of Diseases, 10th Revision. It’s a medical coding system used worldwide to diagnose and classify diseases and conditions. Each diagnosis has a unique code that helps track healthcare data and billing purposes.

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Classifying Your Pyelonephritis ICD-10 code:

N10: Acute Pyelonephritis: This is the main code for a new or sudden onset of pyelonephritis.

Now, let’s explore some specific scenarios:

Unspecified Pyelonephritis (N10.9): Use this code when you know it’s pyelonephritis, but the specific details (acute or chronic, laterality) are unclear.
Chronic Pyelonephritis (N11): This category represents ongoing or recurring pyelonephritis. Here are some subcodes for further clarification:
- N11.0: Chronic pyelonephritis associated with vesicoureteral reflux (urine flowing backward from the bladder to the kidneys).
- N11.1: Chronic obstructive pyelonephritis (caused by a blockage in the urinary tract).
- N11.8: Other chronic tubulo-interstitial nephritis (including nonobstructive chronic pyelonephritis not specified elsewhere).
ICD-10 Code for Acute Pyelonephritis with UTI (N10): While there’s no separate code specifically for “acute pyelonephritis with UTI” (urinary tract infection), N10 can be used for acute pyelonephritis, as it often arises from a UTI that travels to the kidneys.
N12: Unspecified Interstitial Nephritis: This code is used for inflammation of the kidney tissue, but it doesn’t differentiate between pyelonephritis and other causes. If pyelonephritis is confirmed, use the N10 or N11 codes.
Right Pyelonephritis (N10.0) or Left Pyelonephritis ICD-10 (N10.1): These codes specify the affected kidney (right or left) in cases of acute pyelonephritis.
ICD-10 Code for Pyelonephritis with Sepsis (N10 with additional code): There’s no single code for pyelonephritis with sepsis. However, you can use N10 (pyelonephritis) along with a code from the A40-A49 range (sepsis) to indicate the presence of both conditions. The specific A40-A49 code will depend on the severity of the sepsis.
Pyelonephritis in Pregnancy (N11 with additional code): Use the appropriate chronic pyelonephritis code (N11.0, N11.1, or N11.8) along with an additional code from the O98 range (complications of pregnancy) to indicate pyelonephritis during pregnancy.

Physicians often use the term “urinary tract infection” (UTI) when referring to conditions such as urethritis, cystitis, or pyelonephritis. Urethritis and cystitis are lower urinary tract infections; pyelonephritis is an infection of the upper urinary tract. The main term for the specific condition in the Alphabetic Index should be reviewed before checking the main term Infection. For example, under the main term Cystitis, subterms are located for diphtheritic (A36.85) and chlamydial (A56.01) infection. When there is no subterm for the organism, the code for the condition is assigned, with an additional code from categories B95–B97 to indicate the organism. For example, there is no subterm for Escherichia coli under the main term Cystitis; therefore, codes N30.90 and B96.20 are assigned for cystitis due to E. coli.

The following examples indicate complete coding for such infections:

A59.03 Cystitis due to trichomonas
N30.00 + B96.4 Acute cystitis due to proteus infection
N11.9 + B96.20 Chronic pyelonephritis due to E. coli