Acute and subacute hemorrhagic leukoencephalitis [Hurst]

This code represents a rare, severe inflammatory demyelinating disease of the central nervous system characterized by acute onset, hemorrhage, and necrosis within the white matter. It is a fulminant variant of acute disseminated encephalomyelitis (ADEM), often leading to rapid neurological deterioration. The condition is typically post-infectious or post-vaccination, involving an immune-mediated attack on myelin.

Use this code for patients presenting with rapid onset of encephalopathy, seizures, focal neurological deficits, and evidence of hemorrhagic lesions on neuroimaging, particularly in the white matter. Documentation should clearly indicate a diagnosis of acute hemorrhagic leukoencephalitis, often referred to as Hurst's disease, with supporting MRI or CT findings showing multifocal white matter lesions with petechial hemorrhages.

• Differentiate from other forms of ADEM (G04.00, G04.01) which typically lack the hemorrhagic component.
• Ensure documentation specifies "hemorrhagic" to support this specific code over broader demyelinating conditions.
• Sequence this code as the primary diagnosis when it is the reason for the encounter.