ICD-10-CM Book 2026 Edition

Chapters  /  Chapter 6  /  G00-G09

Inflammatory diseases of the central nervous system (G00-G09)

G00 Bacterial meningitis, not elsewhere classified
Includes bacterial arachnoiditis
bacterial leptomeningitis
bacterial meningitis
bacterial pachymeningitis
Excludes1 bacterial meningoencephalitis (G04.2)
bacterial meningomyelitis (G04.2)
G00.0 Hemophilus meningitis
Meningitis due to Hemophilus influenzae
G00.1 Pneumococcal meningitis
Meningitis due to Streptococcal pneumoniae
G00.2 Streptococcal meningitis
UseAdditionalCode code to further identify organism (B95.0-B95.5)
G00.3 Staphylococcal meningitis
UseAdditionalCode code to further identify organism (B95.61-B95.8)
G00.8 Other bacterial meningitis
Meningitis due to Escherichia coli
Meningitis due to Friedländer's bacillus
Meningitis due to Klebsiella
UseAdditionalCode code to further identify organism (B96.-)
G00.9 Bacterial meningitis, unspecified
Meningitis due to gram-negative bacteria, unspecified
Purulent meningitis NOS
Pyogenic meningitis NOS
Suppurative meningitis NOS
G01 Meningitis in bacterial diseases classified elsewhere
CodeFirst underlying disease
Excludes1 meningitis (in):
gonococcal (A54.81)
leptospirosis (A27.81)
listeriosis (A32.11)
Lyme disease (A69.21)
meningococcal (A39.0)
neurosyphilis (A52.13)
tuberculosis (A17.0)
meningoencephalitis and meningomyelitis in bacterial diseases classified elsewhere (G05)
nonPrimary Yes
G02 Meningitis in other infectious and parasitic diseases classified elsewhere
CodeFirst underlying disease, such as:
African trypanosomiasis (B56.-)
poliovirus infection (A80.-)
Excludes1 candidal meningitis (B37.5)
coccidioidomycosis meningitis (B38.4)
cryptococcal meningitis (B45.1)
herpesviral [herpes simplex] meningitis (B00.3)
infectious mononucleosis complicated by meningitis (B27.- with fifth character 2)
measles complicated by meningitis (B05.1)
meningoencephalitis and meningomyelitis in other infectious and parasitic diseases classified elsewhere (G05)
mumps meningitis (B26.1)
rubella meningitis (B06.02)
varicella [chickenpox] meningitis (B01.0)
zoster meningitis (B02.1)
nonPrimary Yes
G03 Meningitis due to other and unspecified causes
Includes arachnoiditis NOS
leptomeningitis NOS
meningitis NOS
pachymeningitis NOS
Excludes1 meningoencephalitis (G04.-)
meningomyelitis (G04.-)
G03.0 Nonpyogenic meningitis
Aseptic meningitis
Nonbacterial meningitis
G03.1 Chronic meningitis
G03.2 Benign recurrent meningitis [Mollaret]
G03.8 Meningitis due to other specified causes
G03.9 Meningitis, unspecified
Arachnoiditis (spinal) NOS
G04 Encephalitis, myelitis and encephalomyelitis
Includes acute ascending myelitis
meningoencephalitis
meningomyelitis
Excludes1 encephalopathy NOS (G93.40)
Excludes2 acute transverse myelitis (G37.3)
alcoholic encephalopathy (G31.2)
multiple sclerosis (G35-)
myalgic encephalomyelitis (G93.32)
subacute necrotizing myelitis (G37.4)
toxic encephalitis (G92.8)
toxic encephalopathy (G92.8)
G04.0 Acute disseminated encephalitis and encephalomyelitis (ADEM)
Excludes1 acute necrotizing hemorrhagic encephalopathy (G04.3-)
other noninfectious acute disseminated encephalomyelitis (noninfectious ADEM) (G04.81)
G04.00 Acute disseminated encephalitis and encephalomyelitis, unspecified
G04.01 Postinfectious acute disseminated encephalitis and encephalomyelitis (postinfectious ADEM)
Excludes1 post chickenpox encephalitis (B01.1)
post measles encephalitis (B05.0)
post measles myelitis (B05.1)
G04.02 Postimmunization acute disseminated encephalitis, myelitis and encephalomyelitis
Encephalitis, post immunization
Encephalomyelitis, post immunization
UseAdditionalCode code to identify the vaccine (T50.A-, T50.B-, T50.Z-)
G04.1 Tropical spastic paraplegia
G04.2 Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified
G04.3 Acute necrotizing hemorrhagic encephalopathy
Excludes1 acute disseminated encephalitis and encephalomyelitis (G04.0-)
G04.30 Acute necrotizing hemorrhagic encephalopathy, unspecified
G04.31 Postinfectious acute necrotizing hemorrhagic encephalopathy
G04.32 Postimmunization acute necrotizing hemorrhagic encephalopathy
UseAdditionalCode code to identify the vaccine (T50.A-, T50.B-, T50.Z-)
G04.39 Other acute necrotizing hemorrhagic encephalopathy
CodeAlso underlying etiology, if applicable
G04.8 Other encephalitis, myelitis and encephalomyelitis
CodeAlso any associated seizure (G40.-, R56.9)
G04.81 Other encephalitis and encephalomyelitis
Noninfectious acute disseminated encephalomyelitis (noninfectious ADEM)
G04.82 Acute flaccid myelitis
Excludes1 transverse myelitis (G37.3)
G04.89 Other myelitis
G04.9 Encephalitis, myelitis and encephalomyelitis, unspecified
G04.90 Encephalitis and encephalomyelitis, unspecified
Ventriculitis (cerebral) NOS
G04.91 Myelitis, unspecified
G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewhere
CodeFirst underlying disease, such as:
congenital toxoplasmosis encephalitis, myelitis and encephalomyelitis (P37.1)
cytomegaloviral encephalitis, myelitis and encephalomyelitis (B25.8)
encephalitis, myelitis and encephalomyelitis (in) systemic lupus erythematosus (M32.19)
eosinophilic meningoencephalitis (B83.2)
human immunodeficiency virus [HIV] disease (B20)
poliovirus (A80.-)
suppurative otitis media (H66.01-H66.4)
systemic lupus erythematosus (M32.19)
trichinellosis (B75)
Excludes1 adenoviral encephalitis, myelitis and encephalomyelitis (A85.1)
encephalitis, myelitis and encephalomyelitis (in) measles (B05.0)
enteroviral encephalitis, myelitis and encephalomyelitis (A85.0)
herpesviral [herpes simplex] encephalitis, myelitis and encephalomyelitis (B00.4)
listerial encephalitis, myelitis and encephalomyelitis (A32.12)
meningococcal encephalitis, myelitis and encephalomyelitis (A39.81)
mumps encephalitis, myelitis and encephalomyelitis (B26.2)
postchickenpox encephalitis, myelitis and encephalomyelitis (B01.1-)
rubella encephalitis, myelitis and encephalomyelitis (B06.01)
toxoplasmosis encephalitis, myelitis and encephalomyelitis (B58.2)
zoster encephalitis, myelitis and encephalomyelitis (B02.0)
G05.3 Encephalitis and encephalomyelitis in diseases classified elsewhere
Meningoencephalitis in diseases classified elsewhere
CodeFirst underlying disease
nonPrimary Yes
G05.4 Myelitis in diseases classified elsewhere
Meningomyelitis in diseases classified elsewhere
nonPrimary Yes
G06 Intracranial and intraspinal abscess and granuloma
UseAdditionalCode code (B95-B97) to identify infectious agent.
G06.0 Intracranial abscess and granuloma
Brain [any part] abscess (embolic)
Cerebellar abscess (embolic)
Cerebral abscess (embolic)
Intracranial epidural abscess or granuloma
Intracranial extradural abscess or granuloma
Intracranial subdural abscess or granuloma
Otogenic abscess (embolic)
Excludes1 tuberculous intracranial abscess and granuloma (A17.81)
G06.1 Intraspinal abscess and granuloma
Abscess (embolic) of spinal cord [any part]
Intraspinal epidural abscess or granuloma
Intraspinal extradural abscess or granuloma
Intraspinal subdural abscess or granuloma
Excludes1 tuberculous intraspinal abscess and granuloma (A17.81)
G06.2 Extradural and subdural abscess, unspecified
G07 Intracranial and intraspinal abscess and granuloma in diseases classified elsewhere
CodeFirst underlying disease, such as:
schistosomiasis granuloma of brain (B65.-)
Excludes1 abscess of brain:
amebic (A06.6)
chromomycotic (B43.1)
gonococcal (A54.82)
tuberculous (A17.81)
tuberculoma of meninges (A17.1)
nonPrimary Yes
G08 Intracranial and intraspinal phlebitis and thrombophlebitis
Septic embolism of intracranial or intraspinal venous sinuses and veins
Septic endophlebitis of intracranial or intraspinal venous sinuses and veins
Septic phlebitis of intracranial or intraspinal venous sinuses and veins
Septic thrombophlebitis of intracranial or intraspinal venous sinuses and veins
Septic thrombosis of intracranial or intraspinal venous sinuses and veins
Excludes1 intracranial phlebitis and thrombophlebitis complicating:
abortion, ectopic or molar pregnancy (O00-O07, O08.7)
pregnancy, childbirth and the puerperium (O22.5, O87.3)
nonpyogenic intracranial phlebitis and thrombophlebitis (I67.6)
Excludes2 intracranial phlebitis and thrombophlebitis complicating nonpyogenic intraspinal phlebitis and thrombophlebitis (G95.1)
G09 Sequelae of inflammatory diseases of central nervous system
Notes Category G09 is to be used to indicate conditions whose primary classification is to G00-G08 as the cause of sequelae, themselves classifiable elsewhere. The 'sequelae' include conditions specified as residuals.
CodeFirst condition resulting from (sequela) of inflammatory diseases of central nervous system