E51.2Wernicke's encephalopathy

E51.2 is the ICD-10-CM diagnosis code for Wernicke's encephalopathy. It belongs to category E51 (thiamine deficiency), block E50-E64 (other nutritional deficiencies) and chapter 4 (endocrine, nutritional and metabolic diseases). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within E51 (thiamine deficiency), E51.2 is specifically for Wernicke's encephalopathy. Related codes cover beriberi (E51.1), other manifestations of thiamine deficiency (E51.8) and unspecified (E51.9).

As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.

In MS-DRG v44.0, it is part of the grouping logic for DRG 640 (Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC, relative weight 1.3395) and DRG 641 (Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC, relative weight 0.7865), in MDC 10 (Endocrine, Nutritional and Metabolic Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 265.1 (other and unspecified manifestations of thiamine deficiency).