A39.81Meningococcal encephalitis

A39.81 is the ICD-10-CM diagnosis code for meningococcal encephalitis. It belongs to category A39 (meningococcal infection), block A30-A49 (other bacterial diseases) and chapter 1 (certain infectious and parasitic 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 A39.8 (other meningococcal infections), A39.81 is specifically for meningococcal encephalitis. Related codes cover meningococcal retrobulbar neuritis (A39.82), meningococcal arthritis (A39.83), Postmeningococcal arthritis (A39.84) and other meningococcal infections (A39.89).

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 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, relative weight 5.7444), DRG 024 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis without MCC, relative weight 3.9708), DRG 094 (Bacterial and Tuberculous Infections of Nervous System with MCC, relative weight 3.4124), DRG 095 (Bacterial and Tuberculous Infections of Nervous System with CC, relative weight 2.3492) and DRG 096 (Bacterial and Tuberculous Infections of Nervous System without CC/MCC, relative weight 2.3213), in MDC 01 (Diseases and Disorders of the Nervous System), 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 036.1 (meningococcal encephalitis).