N31.8

ICD-10-CM N31.8 - Other Neuromuscular Dysfunction of Bladder

Overview

N31.8 is a specific and billable/valid ICD-10-CM code used to indicate a diagnosis of “Other neuromuscular dysfunction of bladder.” It is used for reimbursement purposes to indicate a diagnosis on a claim.

Neuromuscular dysfunction of the bladder (often falling under the umbrella of “neurogenic bladder”) occurs when there is an interruption or dysfunction in the nerve signals connecting the bladder to the brain and spinal cord, leading to abnormal urine storage or voiding. Code N31.8 is utilized when the dysfunction is specified by the provider but does not fit into the other subcategories (such as uninhibited, reflex, or flaccid neuropathic bladder). This might include specific clinical diagnoses like detrusor sphincter dyssynergia.

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Code Hierarchy

• Chapter 14 Diseases of the genitourinary system (N00-N99)

  • Block Other diseases of the urinary system (N30-N39)

    • Category Neuromuscular dysfunction of bladder, not elsewhere classified (N31)

      • Code N31.8 Other neuromuscular dysfunction of bladder

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Coding Guidelines & Conventions

Includes

While there are no specific “Includes” notes directly under N31.8, the parent category N31 applies to conditions described as neuropathic or neurogenic bladder dysfunction that are not classified elsewhere.

Excludes1

A Type 1 Excludes note indicates conditions that cannot be coded alongside N31.8 because the conditions are mutually exclusive.

• Cord bladder NOS (G95.89)

• Neurogenic bladder due to cauda equina syndrome (G83.4)

• Neuromuscular dysfunction due to spinal cord lesion (G95.89)

Use Additional Code

ICD-10-CM explicitly directs coders to use an additional code to identify any associated urinary incontinence when coding N31.8:

• Urge incontinence (N39.41)

• Mixed incontinence (N39.46)

• Other specified urinary incontinence (N39.49-)

• Note Ensure you abstract the specific type of incontinence documented in the chart to satisfy this requirement.

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Reimbursement & Risk Adjustment

MS-DRG Mapping

When assigned in the inpatient setting, N31.8 groups to the following Medical and Surgical Diagnosis-Related Groups (MS-DRG v43.0):

• MS-DRG 698 Other kidney and urinary tract diagnoses with MCC (Major Complication or Comorbidity)

• MS-DRG 699 Other kidney and urinary tract diagnoses with CC (Complication or Comorbidity)

• MS-DRG 700 Other kidney and urinary tract diagnoses without CC/MCC

HCC (Hierarchical Condition Category)

• CMS-HCC (V28) Code N31.8 does not currently map to a standard CMS-HCC category for Medicare Advantage risk adjustment in the V28 model.

• Note Always check specific commercial or Medicaid payer proprietary models, as some plans do assign risk adjustment value to specific neurogenic bladder codes even if CMS does not.

wRVU & Assistant Surgeon Payable

• wRVU Not Applicable. (N31.8 is an ICD-10-CM diagnosis code. Work Relative Value Units apply strictly to CPT/HCPCS procedure codes).

• Assistant Payable Not Applicable.

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Clinical Coding Examples

Scenario 1 (Profee Focus)

Clinical Documentation A 68-year-old patient with advanced Parkinson’s disease presents for a urology consult. The urologist documents “neuromuscular bladder dysfunction causing detrusor sphincter dyssynergia and associated urge incontinence, secondary to Parkinson’s disease.”

Coding 1. G20 (Parkinson’s disease) - Sequenced first as the underlying etiology.

2. N31.8 (Other neuromuscular dysfunction of bladder) - The specific bladder manifestation.

3. N39.41 (Urge incontinence) - Satisfies the “Use additional code” directive for associated incontinence.

Scenario 2 (Inpatient Focus)

Clinical Documentation Patient is admitted with severe dehydration and an acute urinary tract infection. During the admission, the attending physician notes the patient has a complex urological history, specifically documenting “sensory paralytic bladder” which complicates the current fluid and catheterization management plan.

Coding 1. N39.0 (Urinary tract infection, site not specified) - Principal diagnosis.

2. E86.0 (Dehydration) - Secondary diagnosis.

3. N31.8 (Other neuromuscular dysfunction of bladder) - Secondary diagnosis to capture the sensory paralytic bladder impacting inpatient care.

Warning

Watch Out If the documentation had stated the dysfunction was due to a spinal cord lesion, you would follow the Excludes1 note and look to G95.89 instead of N31.8.