Symptoms of PRES: Diagnosis, Treatment, and ICD-10-CM Coding Guidance

Introduction to PRES Symptoms, Causes, and Coding

Posterior Reversible Encephalopathy Syndrome (PRES), also known in clinical literature as reversible posterior leukoencephalopathy syndrome, is a neurologic condition characterized by acute changes in mental status, seizures, headaches, and visual disturbances. Because the symptoms of PRES can overlap with other encephalopathic presentations, accurate documentation is essential for correct ICD-10-CM coding, DRG assignment, severity capture, and CDI review.

What Is PRES? Understanding the Medical Term and Clinical Features

PRES is a clinical radiographic syndrome defined by a constellation of neurologic symptoms and characteristic imaging findings. Alternate terminology includes:

• Reversible posterior leukoencephalopathy syndrome (RPLS)
• Reversible posterior cerebral edema syndrome
• Hyperperfusion encephalopathy
• Brain capillary leak syndrome

Common clinical presentations include:

• Headache
• Seizures
• Altered mental status or confusion
• Visual disturbances (blurred vision, cortical blindness, visual field loss)

Clinical settings commonly associated with PRES include hypertensive crisis, cytotoxic immunosuppressive therapy, pre-eclampsia/eclampsia, and other conditions that cause endothelial injury.

Imaging Findings That Support a Diagnosis of PRES

Neuroimaging, particularly MRI, typically shows:

• Vasogenic edema
• Predominant involvement of posterior cerebral regions
• Symmetric white matter changes

These imaging features are foundational in differentiating PRES from other encephalopathies.

Treatment of PRES and Key Management Principles

The treatment of PRES focuses on addressing the underlying cause and preventing further neurologic injury. Management strategies include:

• Tight blood pressure control
• Discontinuation of offending agents (especially cytotoxic medications)
• Seizure management
• Obstetric protocols when PRES occurs during pregnancy (treated as pre-eclampsia or eclampsia)

Most patients recover within two weeks; however, some may experience persistent neurologic deficits or, in severe cases, complications such as intracranial hemorrhage or cerebral infarction.

ICD-10-CM Coding for PRES (I67.83) and CDI Considerations

The ICD-10-CM code for PRES is I67.83.

Key coding and CDI notes:

• PRES is classified as an MCC when assigned as a secondary diagnosis.
• When PRES is the principal diagnosis, it groups to MS-DRG 070, 071, or 072 (Other cerebrovascular disorders).
• Cerebral edema is not coded separately, as it is inherent to PRES.
• PRES is a recognized risk-adjusting condition demonstrating severity of illness.
• Documentation must clearly link PRES to the underlying cause when clinically supported.
• Documentation of “encephalopathy” alone does not support coding PRES; a CDI query is indicated if the diagnosis is unclear or inconsistently documented.

Secondary Diagnoses That Impact DRG and Severity Capture

When reviewing documentation, CDI specialists should assess for commonly associated secondary diagnoses, including:

• Acidosis
• Acute renal failure
• Coma
• Cerebral infarction or stroke
• ESRD
• Secondary hyperparathyroidism

These conditions may significantly impact DRG assignment and severity reporting.

Query Opportunities for PRES Documentation

A CDI query may be appropriate when:

• “Encephalopathy” is documented without clarification of the type
• Imaging findings are consistent with PRES but the provider does not document the diagnosis
• The underlying cause (e.g., hypertensive crisis, cytotoxic drug use, pre-eclampsia) is not explicitly linked to PRES
• Conflicting terminology appears in the record

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Alyce Reavis, RN,MSN,CCDS,CCS 

Senior CDI Educator, Consulting Services at UASI

Drawing on clinical experience in adult, pediatric, and neonatal acute care, Alyce brings valuable insight to CDI education and documentation improvement. She holds an MSN in Leadership/Education along with CCDS, CCS, and AHIMA’s outpatient CDI micro credential, supporting health systems in strengthening documentation accuracy, quality reporting, and reimbursement integrity. Passionate about truthful, clinically aligned health records, she helps organizations ensure documentation reflects true patient acuity. She is a past presenter for the ACDIS National Convention, Local chapter meetings, and the ACDIS Virtual Best Practices conference. 

Works Cited

Centers for Medicare & Medicaid Services. (2025). FY 2026 Official Guidelines for Coding and Reporting.
Available at https://www.cms.gov

Centers for Medicare & Medicaid Services. (2025). IPPS Final Rule for Fiscal Year 2026.
Available at https://www.cms.gov

Neill, T. (2025). Posterior reversible encephalopathy syndrome. UpToDate.
Available at https://www.uptodate.com/contents/posterior-reversible-encephalopathy-syndrome