ICD-9 Diagnosis Code 323.9

Encephalitis NOS

Diagnosis Code 323.9

ICD-9: 323.9
Short Description: Encephalitis NOS
Long Description: Unspecified causes of encephalitis, myelitis, and encephalomyelitis
This is the 2014 version of the ICD-9-CM diagnosis code 323.9

Code Classification
  • Diseases of the nervous system (320–359)
    • Inflammatory diseases of the central nervous system (320-327)
      • 323 Encephalitis, myelitis, and encephalomyelitis

Information for Medical Professionals

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The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.

  • Acute and subacute hemorrhagic leukoencephalitis
  • Acute ascending myelitis
  • Acute necrotizing myelitis
  • Acute non-infective transverse myelitis
  • Acute transverse myelitis
  • Acute viral transverse myelitis
  • Brainstem encephalitis
  • Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
  • Cerebral irritation
  • Encephalitis
  • Encephalitis associated with acquired immunodeficiency syndrome
  • Encephalitis, myelitis and encephalomyelitis
  • Encephalomyelitis
  • Focal encephalitis
  • Fungal infection of brain
  • Granulomatous meningoencephalitis
  • Granulomatous meningoencephalomyelitis
  • Inflammation of spinal cord due to toxin
  • Leukoencephalopathy
  • Limbic encephalitis
  • Meningoencephalomyelitis
  • Meningomyelitis
  • Myelitis
  • Myelitis associated with acquired immunodeficiency syndrome
  • Primary encephalitis
  • Rasmussen syndrome
  • Subacute hemorrhagic leukoencephalitis
  • Subacute necrotizing myelitis
  • Transverse myelopathy syndrome

Index of Diseases and Injuries
References found for the code 323.9 in the Index of Diseases and Injuries:

Information for Patients


Encephalitis is an inflammation of the brain. Usually the cause is a viral infection, but bacteria can also cause it. It can be mild or severe. Most cases are mild. You may have flu-like symptoms. With a mild case, you may just need rest, plenty of fluids, and a pain reliever.

Severe cases need immediate treatment. Symptoms of severe cases include

  • Severe headache
  • Sudden fever
  • Drowsiness
  • Vomiting
  • Confusion
  • Seizures

In babies, additional symptoms may include constant crying, poor feeding, body stiffness, and bulging in the soft spots of the skull.

Severe cases may require a stay in the hospital. Treatments include oral and intravenous medicines to reduce inflammation and treat infection. Patients with breathing difficulties may need artificial respiration. Some people may need physical, speech, and occupational therapy once the illness is under control.

NIH: National Institute of Neurological Disorders and Stroke

  • Cerebral spinal fluid (CSF) collection
  • CSF analysis
  • Encephalitis
  • Japanese Encephalitis Vaccine: What You Need to Know (Centers for Disease Control and Prevention)
  • Subacute sclerosing panencephalitis

[Read More]

Neurologic Diseases

Also called: Nervous system diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

There are more than 600 neurologic diseases. Major types include

  • Diseases caused by faulty genes, such as Huntington's disease and muscular dystrophy
  • Problems with the way the nervous system develops, such as spina bifida
  • Degenerative diseases, where nerve cells are damaged or die, such as Parkinson's disease and Alzheimer's disease
  • Diseases of the blood vessels that supply the brain, such as stroke
  • Injuries to the spinal cord and brain
  • Seizure disorders, such as epilepsy
  • Cancer, such as brain tumors
  • infections, such as meningitis

  • Cerebral spinal fluid (CSF) collection
  • EEG

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