E05.91Thyrotoxicosis, unspecified with thyrotoxic crisis or storm

E05.91 is the ICD-10-CM diagnosis code for thyrotoxicosis, unspecified with thyrotoxic crisis or storm. It belongs to category E05 (thyrotoxicosis [hyperthyroidism]), block E00-E07 (disorders of thyroid gland) 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 E05.9 (thyrotoxicosis, unspecified), E05.91 is specifically for thyrotoxicosis, unspecified with thyrotoxic crisis or storm. Related codes cover without thyrotoxic crisis or storm (E05.90).

As a secondary diagnosis it is an MCC (major complication or comorbidity), which can move an inpatient stay into the highest-paying "with MCC" 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 011 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with MCC, relative weight 5.6154), DRG 012 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy with CC, relative weight 4.381), DRG 013 (Tracheostomy for Face, Mouth and Neck Diagnoses or Laryngectomy without CC/MCC, relative weight 2.7307), DRG 643 (Endocrine Disorders with MCC, relative weight 1.6139), DRG 644 (Endocrine Disorders with CC, relative weight 1.0044) and DRG 645 (Endocrine Disorders without CC/MCC, relative weight 0.7459), in Pre-MDC and 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 242.91 (thyrotoxicosis without mention of goiter or other cause, with mention of thyrotoxic crisis or storm).