Encephalitis, myelitis and encephalomyelitis (G04)

Browse all the diagnosis codes used for encephalitis, myelitis and encephalomyelitis (g04). For easy navigation, the diagnosis codes are sorted in alphabetical order and grouped by sections. Each section is clearly marked with its description, and the corresponding three-digit code range. This format makes it simple to browse diagnosis codes in this chapter or section and find what you're looking for. We've also added green checkmark icons to label billable codes, and red warning icons for non-billable ones. This makes it easy to identify which codes can be billed.

Clinical Information

Alphavirus - A genus of TOGAVIRIDAE, also known as Group A arboviruses, serologically related to each other but not to other Togaviridae. The viruses are transmitted by mosquitoes. The type species is the SINDBIS VIRUS.

Alphavirus Infections - Virus diseases caused by members of the ALPHAVIRUS genus of the family TOGAVIRIDAE.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis - Disorder characterized by symptoms of CATATONIA; HYPOVENTILATION; DYSKINESIAS; ENCEPHALITIS; and SEIZURES followed by a reduced CONSCIOUSNESS. It is often followed by a viral-like prodrome. Many cases are self-limiting and respond well to IMMUNOMODULATORY THERAPIES against the NMDA RECEPTORS antibodies.

Ascaridida - An order of nematodes of the subclass SECERNENTEA. Its organisms possess two or three pairs of dorsolateral caudal papillae.

Ascaridida Infections - Infections with nematodes of the order ASCARIDIDA.

Autoimmune Diseases of the Nervous System - Disorders caused by cellular or humoral immune responses primarily directed towards nervous system autoantigens. The immune response may be directed towards specific tissue components (e.g., myelin) and may be limited to the central nervous system (e.g., MULTIPLE SCLEROSIS) or the peripheral nervous system (e.g., GUILLAIN-BARRE SYNDROME).

Betacoronavirus 1 - The type species of BETACORONAVIRUS genus causing gastroenteritis respiratory diseases in mammals. Previously separate species HUMAN CORONAVIRUS OC43; BOVINE CORONAVIRUS; Human enteric coronavirus; Equine coronavirus; and Porcine hemagglutinating encephalomyelitis virus merged into this species on the basis of similar genome nucleotide sequence and genome organization.

Borna disease virus - A species in the genus Bornavirus, family BORNAVIRIDAE, causing a rare and usually fatal encephalitic disease in horses and other domestic animals and possibly deer. Its name derives from the city in Saxony where the condition was first described in 1894, but the disease occurs in Europe, N. Africa, and the Near East.

Bornaviridae - A family in the order MONONEGAVIRALES comprising one genus Bornavirus. This family has a unique form of mRNA processing: replication and transcription takes place in the nucleus.

Cardiovirus - A genus of the family PICORNAVIRIDAE causing encephalitis and myocarditis in rodents. ENCEPHALOMYOCARDITIS VIRUS is the type species.

Central Nervous System Protozoal Infections - Infections of the brain, spinal cord, or meninges by single celled organisms of the former subkingdom known as protozoa. The central nervous system may be the primary or secondary site of protozoal infection. These diseases may occur as OPPORTUNISTIC INFECTIONS or arise in immunocompetent hosts.

Diffuse Cerebral Sclerosis of Schilder - A rare central nervous system demyelinating condition affecting children and young adults. Pathologic findings include a large, sharply defined, asymmetric focus of myelin destruction that may involve an entire lobe or cerebral hemisphere. The clinical course tends to be progressive and includes dementia, cortical blindness, cortical deafness, spastic hemiplegia, and pseudobulbar palsy. Concentric sclerosis of Balo is differentiated from diffuse cerebral sclerosis of Schilder by the pathologic finding of alternating bands of destruction and preservation of myelin in concentric rings. Alpers' Syndrome refers to a heterogeneous group of diseases that feature progressive cerebral deterioration and liver disease. (From Adams et al., Principles of Neurology, 6th ed, p914; Dev Neurosci 1991;13(4-5):267-73)

Encephalitis - Inflammation of the BRAIN due to infection, autoimmune processes, toxins, and other conditions. Viral infections (see ENCEPHALITIS, VIRAL) are a relatively frequent cause of this condition.

Encephalitis Virus, California - A species in the ORTHOBUNYAVIRUS genus of the family BUNYAVIRIDAE. Serotypes are found in temperate and arctic regions and each is closely associated with a single species of vector mosquito. The vertebrate hosts are usually small mammals but several serotypes infect humans.

Encephalitis Virus, Eastern Equine - A species of ALPHAVIRUS causing encephalomyelitis in Equidae and humans. The virus ranges along the Atlantic seaboard of the United States and Canada and as far south as the Caribbean, Mexico, and parts of Central and South America. Infections in horses show a mortality of up to 90 percent and in humans as high as 80 percent in epidemics.

Encephalitis Virus, Japanese - A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiological agent of Japanese encephalitis found in Asia, southeast Asia, and the Indian subcontinent.

Encephalitis Virus, Murray Valley - A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), found in Australia and New Guinea. It causes a fulminating viremia resembling Japanese encephalitis (ENCEPHALITIS, JAPANESE).

Encephalitis Virus, St. Louis - A species of FLAVIVIRUS, one of the Japanese encephalitis virus group (ENCEPHALITIS VIRUSES, JAPANESE), which is the etiologic agent of ST. LOUIS ENCEPHALITIS in the United States, the Caribbean, and Central and South America.

Encephalitis Virus, Venezuelan Equine - A species of ALPHAVIRUS that is the etiologic agent of encephalomyelitis in humans and equines. It is seen most commonly in parts of Central and South America.

Encephalitis Virus, Western Equine - A species of ALPHAVIRUS that is the etiologic agent of encephalomyelitis in humans and equines in the United States, southern Canada, and parts of South America.

Encephalitis Viruses - A collection of single-stranded RNA viruses scattered across the Bunyaviridae, Flaviviridae, and Togaviridae families whose common property is the ability to induce encephalitic conditions in infected hosts.

Encephalitis Viruses, Japanese - A subgroup of the genus FLAVIVIRUS which comprises a number of viral species that are the etiologic agents of human encephalitis in many different geographical regions. These include Japanese encephalitis virus (ENCEPHALITIS VIRUS, JAPANESE), St. Louis encephalitis virus (ENCEPHALITIS VIRUS, ST. LOUIS), Murray Valley encephalitis virus (ENCEPHALITIS VIRUS, MURRAY VALLEY), and WEST NILE VIRUS.

Encephalitis Viruses, Tick-Borne - A subgroup of the genus FLAVIVIRUS that causes encephalitis and hemorrhagic fevers and is found in eastern and western Europe and the former Soviet Union. It is transmitted by TICKS and there is an associated milk-borne transmission from viremic cattle, goats, and sheep.

Encephalitis, Arbovirus - Infections of the brain caused by arthropod-borne viruses (i.e., arboviruses) primarily from the families TOGAVIRIDAE; FLAVIVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; and RHABDOVIRIDAE. Life cycles of these viruses are characterized by ZOONOSES, with birds and lower mammals serving as intermediate hosts. The virus is transmitted to humans by the bite of mosquitoes (CULICIDAE) or TICKS. Clinical manifestations include fever, headache, alterations of mentation, focal neurologic deficits, and COMA. (From Clin Microbiol Rev 1994 Jan;7(1):89-116; Walton, Brain's Diseases of the Nervous System, 10th ed, p321)

Encephalitis, California - A viral infection of the brain caused by serotypes of California encephalitis virus (ENCEPHALITIS VIRUS, CALIFORNIA) transmitted to humans by the mosquito AEDES triseriatus. The majority of cases are caused by the LA CROSSE VIRUS. This condition is endemic to the midwestern United States and primarily affects children between 5-10 years of age. Clinical manifestations include FEVER; VOMITING; HEADACHE; and abdominal pain followed by SEIZURES, altered mentation, and focal neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13)

Encephalitis, Herpes Simplex - An acute (or rarely chronic) inflammatory process of the brain caused by SIMPLEXVIRUS infections which may be fatal. The majority of infections are caused by human herpesvirus 1 (HERPESVIRUS 1, HUMAN) and less often by human herpesvirus 2 (HERPESVIRUS 2, HUMAN). Clinical manifestations include FEVER; HEADACHE; SEIZURES; HALLUCINATIONS; behavioral alterations; APHASIA; hemiparesis; and COMA. Pathologically, the condition is marked by a hemorrhagic necrosis involving the medial and inferior TEMPORAL LOBE and orbital regions of the FRONTAL LOBE. (From Adams et al., Principles of Neurology, 6th ed, pp751-4)

Encephalitis, Japanese - A mosquito-borne encephalitis caused by the Japanese B encephalitis virus (ENCEPHALITIS VIRUS, JAPANESE) occurring throughout Eastern Asia and Australia. The majority of infections occur in children and are subclinical or have features limited to transient fever and gastrointestinal symptoms. Inflammation of the brain, spinal cord, and meninges may occur and lead to transient or permanent neurologic deficits (including a POLIOMYELITIS-like presentation); SEIZURES; COMA; and death. (From Adams et al., Principles of Neurology, 6th ed, p751; Lancet 1998 Apr 11;351(9109):1094-7)

Encephalitis, St. Louis - A viral encephalitis caused by the St. Louis encephalitis virus (ENCEPHALITIS VIRUS, ST. LOUIS), a FLAVIVIRUS. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus CULEX. The primary animal vectors are wild birds and the disorder is endemic to the midwestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an ASEPTIC MENINGITIS or ENCEPHALITIS. Clinical manifestations of the encephalitic presentation may include SEIZURES, lethargy, MYOCLONUS, focal neurologic signs, COMA, and DEATH. (From Adams et al., Principles of Neurology, 6th ed, p750)

Encephalitis, Tick-Borne - Encephalitis caused by neurotropic viruses that are transmitted via the bite of TICKS. In Europe, the diseases are caused by ENCEPHALITIS VIRUSES, TICK-BORNE, which give rise to Russian spring-summer encephalitis, central European encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in North America and Russia and is caused by the Powassan virus. ASEPTIC MENINGITIS and rarely encephalitis may complicate COLORADO TICK FEVER which is endemic to mountainous regions of the western United States. (From Joynt, Clinical Neurology, 1996, Ch26, pp14-5)

Encephalitis, Varicella Zoster - Inflammation of brain tissue caused by infection with the varicella-zoster virus (HERPESVIRUS 3, HUMAN). This condition is associated with immunocompromised states, including the ACQUIRED IMMUNODEFICIENCY SYNDROME. Pathologically, the virus tends to induce a vasculopathy and infect oligodendrocytes and ependymal cells, leading to CEREBRAL INFARCTION, multifocal regions of demyelination, and periventricular necrosis. Manifestations of varicella encephalitis usually occur 5-7 days after onset of HERPES ZOSTER and include HEADACHE; VOMITING; lethargy; focal neurologic deficits; FEVER; and COMA. (From Joynt, Clinical Neurology, 1996, Ch 26, pp29-32; Hum Pathol 1996 Sep;27(9):927-38)

Encephalitis, Viral - Inflammation of brain parenchymal tissue as a result of viral infection. Encephalitis may occur as primary or secondary manifestation of TOGAVIRIDAE INFECTIONS; HERPESVIRIDAE INFECTIONS; ADENOVIRIDAE INFECTIONS; FLAVIVIRIDAE INFECTIONS; BUNYAVIRIDAE INFECTIONS; PICORNAVIRIDAE INFECTIONS; PARAMYXOVIRIDAE INFECTIONS; ORTHOMYXOVIRIDAE INFECTIONS; RETROVIRIDAE INFECTIONS; and ARENAVIRIDAE INFECTIONS.

Encephalomyelitis - A general term indicating inflammation of the BRAIN and SPINAL CORD, often used to indicate an infectious process, but also applicable to a variety of autoimmune and toxic-metabolic conditions. There is significant overlap regarding the usage of this term and ENCEPHALITIS in the literature.

Encephalomyelitis Virus, Avian - A tentative species in the genus HEPATOVIRUS infecting primarily young chicks, but also found in turkeys, pheasants, and guinea fowl. It causes a fatal neuronal degeneration and is transmitted by mechanical contact.

Encephalomyelitis, Acute Disseminated - An acute or subacute inflammatory process of the CENTRAL NERVOUS SYSTEM characterized histologically by multiple foci of perivascular demyelination. Symptom onset usually occurs several days after an acute viral infection or immunization, but it may coincide with the onset of infection or rarely no antecedent event can be identified. Clinical manifestations include CONFUSION, somnolence, FEVER, nuchal rigidity, and involuntary movements. The illness may progress to COMA and eventually be fatal. (Adams et al., Principles of Neurology, 6th ed, p921)

Encephalomyelitis, Autoimmune, Experimental - An experimental animal model for central nervous system demyelinating disease. Inoculation with a white matter emulsion combined with FREUND'S ADJUVANT, myelin basic protein, or purified central myelin triggers a T cell-mediated immune response directed towards central myelin. The pathologic features are similar to MULTIPLE SCLEROSIS, including perivascular and periventricular foci of inflammation and demyelination. Subpial demyelination underlying meningeal infiltrations also occurs, which is also a feature of ENCEPHALOMYELITIS, ACUTE DISSEMINATED. Passive immunization with T-cells from an afflicted animal to a normal animal also induces this condition. (From Immunol Res 1998;17(1-2):217-27; Raine CS, Textbook of Neuropathology, 2nd ed, p604-5)

Encephalomyelitis, Eastern Equine - A form of arboviral encephalitis (primarily affecting equines) endemic to eastern regions of North America. The causative organism (ENCEPHALOMYELITIS VIRUS, EASTERN EQUINE) may be transmitted to humans via the bite of AEDES mosquitoes. Clinical manifestations include the acute onset of fever, HEADACHE, altered mentation, and SEIZURES followed by coma. The condition is fatal in up to 50% of cases. Recovery may be marked by residual neurologic deficits and EPILEPSY. (From Joynt, Clinical Neurology, 1996, Ch26, pp9-10)

Encephalomyelitis, Enzootic Porcine - A picornavirus infection producing symptoms similar to poliomyelitis in pigs.

Encephalomyelitis, Equine - A group of ALPHAVIRUS INFECTIONS which affect horses and man, transmitted via the bites of mosquitoes. Disorders in this category are endemic to regions of South America and North America. In humans, clinical manifestations vary with the type of infection, and range from a mild influenza-like syndrome to a fulminant encephalitis. (From Joynt, Clinical Neurology, 1996, Ch26, pp8-10)

Encephalomyelitis, Venezuelan Equine - A form of arboviral encephalitis endemic to Central America and the northern latitudes of South America. The causative organism (ENCEPHALITIS VIRUS, VENEZUELAN EQUINE) is transmitted to humans and horses via the bite of several mosquito species. Human viral infection may be asymptomatic or remain restricted to a mild influenza-like illness. Encephalitis, usually not severe, occurs in a small percentage of cases and may rarely feature SEIZURES and COMA. (From Joynt, Clinical Neurology, 1996, Ch26, pp9-10)

Encephalomyelitis, Western Equine - A form of arboviral encephalitis (which primarily affects horses) endemic to western and central regions of NORTH AMERICA. The causative organism (ENCEPHALOMYELITIS VIRUS, WESTERN EQUINE) may be transferred to humans via the bite of mosquitoes (CULEX tarsalis and others). Clinical manifestations include headache and influenza-like symptoms followed by alterations in mentation, SEIZURES, and COMA. DEATH occurs in a minority of cases. Survivors may recover fully or be left with residual neurologic dysfunction, including PARKINSONISM, POSTENCEPHALITIC. (From Joynt, Clinical Neurology, 1996, Ch26, pp8-9)

Encephalopathy, Bovine Spongiform - A transmissible spongiform encephalopathy of cattle associated with abnormal prion proteins in the brain. Affected animals develop excitability and salivation followed by ATAXIA. This disorder has been associated with consumption of SCRAPIE infected ruminant derived protein. This condition may be transmitted to humans, where it is referred to as variant or new variant CREUTZFELDT-JAKOB SYNDROME. (Vet Rec 1998 Jul 25;143(41):101-5)

Fatigue Syndrome, Chronic - A syndrome characterized by persistent or recurrent fatigue, diffuse musculoskeletal pain, sleep disturbances, and subjective cognitive impairment of 6 months duration or longer. Symptoms are not caused by ongoing exertion; are not relieved by rest; and result in a substantial reduction of previous levels of occupational, educational, social, or personal activities. Minor alterations of immune, neuroendocrine, and autonomic function may be associated with this syndrome. There is also considerable overlap between this condition and FIBROMYALGIA. (From Semin Neurol 1998;18(2):237-42; Ann Intern Med 1994 Dec 15;121(12): 953-9)

Fibromyalgia - A common nonarticular rheumatic syndrome characterized by myalgia and multiple points of focal muscle tenderness to palpation (trigger points). Muscle pain is typically aggravated by inactivity or exposure to cold. This condition is often associated with general symptoms, such as sleep disturbances, fatigue, stiffness, HEADACHES, and occasionally DEPRESSION. There is significant overlap between fibromyalgia and the chronic fatigue syndrome (FATIGUE SYNDROME, CHRONIC). Fibromyalgia may arise as a primary or secondary disease process. It is most frequent in females aged 20 to 50 years. (From Adams et al., Principles of Neurology, 6th ed, p1494-95)

Henipavirus Infections - Infections with viruses of the genus HENIPAVIRUS, family PARAMYXOVIRIDAE.

Hepatovirus - A genus of PICORNAVIRIDAE causing infectious hepatitis naturally in humans and experimentally in other primates. It is transmitted through fecal contamination of food or water. HEPATITIS A VIRUS is the type species.

Herpesvirus 5, Bovine - A species of VARICELLOVIRUS that causes a fatal MENINGOENCEPHALITIS in calves.

Infectious Encephalitis - Brain inflammation caused by an infectious agent.

Japanese Encephalitis Vaccines - Vaccines or candidate vaccines used to prevent infection with Japanese B encephalitis virus (ENCEPHALITIS VIRUS, JAPANESE).

Leigh Disease - A group of metabolic disorders primarily of infancy characterized by the subacute onset of psychomotor retardation, hypotonia, ataxia, weakness, vision loss, eye movement abnormalities, seizures, dysphagia, and lactic acidosis. Pathological features include spongy degeneration of the neuropile of the basal ganglia, thalamus, brain stem, and spinal cord. Patterns of inheritance include X-linked recessive, autosomal recessive, and mitochondrial. Leigh disease has been associated with mutations in genes for the PYRUVATE DEHYDROGENASE COMPLEX; CYTOCHROME-C OXIDASE; ATP synthase subunit 6; and subunits of mitochondrial complex I. (From Menkes, Textbook of Child Neurology, 5th ed, p850).

Leukoencephalitis, Acute Hemorrhagic - A fulminant and often fatal demyelinating disease of the brain which primarily affects young adults and children. Clinical features include the rapid onset of weakness, SEIZURES, and COMA. It may follow a viral illness or MYCOPLASMA PNEUMONIAE infections but in most instances there is no precipitating event. Pathologic examination reveals marked perivascular demyelination and necrosis of white matter with microhemorrhages. (Adams et al., Principles of Neurology, 6th ed, pp924-5)

Leukoencephalopathy, Progressive Multifocal - An opportunistic viral infection of the central nervous system associated with conditions that impair cell-mediated immunity (e.g., ACQUIRED IMMUNODEFICIENCY SYNDROME and other IMMUNOLOGIC DEFICIENCY SYNDROMES; HEMATOLOGIC NEOPLASMS; IMMUNOSUPPRESSION; and COLLAGEN DISEASES). The causative organism is JC Polyomavirus (JC VIRUS) which primarily affects oligodendrocytes, resulting in multiple areas of demyelination. Clinical manifestations include DEMENTIA; ATAXIA; visual disturbances; and other focal neurologic deficits, generally progressing to a vegetative state within 6 months. (From Joynt, Clinical Neurology, 1996, Ch26, pp36-7)

Limbic Encephalitis - A paraneoplastic syndrome marked by degeneration of neurons in the LIMBIC SYSTEM. Clinical features include HALLUCINATIONS, loss of EPISODIC MEMORY; ANOSMIA; AGEUSIA; TEMPORAL LOBE EPILEPSY; DEMENTIA; and affective disturbance (depression). Circulating anti-neuronal antibodies (e.g., anti-Hu; anti-Yo; anti-Ri; and anti-Ma2) and small cell lung carcinomas or testicular carcinoma are frequently associated with this syndrome.

Lupus Vasculitis, Central Nervous System - Central nervous system vasculitis that is associated with SYSTEMIC LUPUS ERYTHEMATOSUS. Clinical manifestations may include DEMENTIA; SEIZURES; CRANIAL NERVE DISEASES; HEMIPARESIS; BLINDNESS; DYSPHASIA; and other neurological disorders.

Lyme Neuroborreliosis - Nervous system infections caused by tick-borne spirochetes of the BORRELIA BURGDORFERI GROUP. The disease may affect elements of the central or peripheral nervous system in isolation or in combination. Common clinical manifestations include a lymphocytic meningitis, cranial neuropathy (most often a facial neuropathy), POLYRADICULOPATHY, and a mild loss of memory and other cognitive functions. Less often more extensive inflammation involving the central nervous system (encephalomyelitis) may occur. In the peripheral nervous system, B. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. (From J Neurol Sci 1998 Jan 8;153(2):182-91)

Lymphocytic Choriomeningitis - A form of meningitis caused by LYMPHOCYTIC CHORIOMENINGITIS VIRUS. MICE and other rodents serve as the natural hosts, and infection in humans usually occurs through inhalation or ingestion of infectious particles. Clinical manifestations include an influenza-like syndrome followed by stiff neck, alterations of mentation, ATAXIA, and incontinence. Maternal infections may result in fetal malformations and injury, including neonatal HYDROCEPHALUS, aqueductal stenosis, CHORIORETINITIS, and MICROCEPHALY. (From Joynt, Clinical Neurology, 1996, Ch26, pp1-3)

Maus Elberfeld virus - A strain of ENCEPHALOMYOCARDITIS VIRUS, a species of CARDIOVIRUS, usually causing an inapparent intestinal infection in mice. A small number of mice may show signs of flaccid paralysis.

Meningitis, Listeria - Inflammation of the meninges caused by LISTERIA MONOCYTOGENES infection, usually occurring in individuals under the age of 3 years or over the age of 50 years. It may occur at any age in individuals with IMMUNOLOGIC DEFICIENCY SYNDROMES. Clinical manifestations include FEVER, altered mentation, HEADACHE, meningeal signs, focal neurologic signs, and SEIZURES. (From Medicine 1998 Sep;77(5):313-36)

Meningoencephalitis - An inflammatory process involving the brain (ENCEPHALITIS) and meninges (MENINGITIS), most often produced by pathogenic organisms which invade the central nervous system, and occasionally by toxins, autoimmune disorders, and other conditions.

Myelitis - Inflammation of the spinal cord. Relatively common etiologies include infections; AUTOIMMUNE DISEASES; SPINAL CORD; and ischemia (see also SPINAL CORD VASCULAR DISEASES). Clinical features generally include weakness, sensory loss, localized pain, incontinence, and other signs of autonomic dysfunction.

Myelitis, Transverse - Inflammation of a transverse portion of the spinal cord characterized by acute or subacute segmental demyelination or necrosis. The condition may occur sporadically, follow an infection or vaccination, or present as a paraneoplastic syndrome (see also ENCEPHALOMYELITIS, ACUTE DISSEMINATED). Clinical manifestations include motor weakness, sensory loss, and incontinence. (Adams et al., Principles of Neurology, 6th ed, pp1242-6)

Neuroschistosomiasis - SCHISTOSOMIASIS of the brain, spinal cord, or meninges caused by infections with trematodes of the genus SCHISTOSOMA (primarily SCHISTOSOMA JAPONICUM; SCHISTOSOMA MANSONI; and SCHISTOSOMA HAEMATOBIUM in humans). S. japonicum infections of the nervous system may cause an acute meningoencephalitis or a chronic encephalopathy. S. mansoni and S. haematobium nervous system infections are associated with acute transverse myelitis involving the lower portions of the spinal cord. (From Joynt, Clinical Neurology, 1998, Ch27, pp61-2)

Neurotoxicity Syndromes - Neurologic disorders caused by exposure to toxic substances through ingestion, injection, cutaneous application, or other method. This includes conditions caused by biologic, chemical, and pharmaceutical agents.

Opportunistic Infections - An infection caused by an organism which becomes pathogenic under certain conditions, e.g., during immunosuppression.

Paraneoplastic Syndromes, Nervous System - Degenerative or inflammatory conditions affecting the central or peripheral nervous system that develop in association with a systemic neoplasm without direct invasion by tumor. They may be associated with circulating antibodies that react with the affected neural tissue. (Intern Med 1996 Dec;35(12):925-9)

Parkinson Disease, Postencephalitic - Parkinsonism following encephalitis, historically seen as a sequella of encephalitis lethargica (Von Economo Encephalitis). The early age of onset, the rapid progression of symptoms followed by stabilization, and the presence of a variety of other neurological disorders (e.g., sociopathic behavior; TICS; MUSCLE SPASMS; oculogyric crises; hyperphagia; and bizarre movements) distinguish this condition from primary PARKINSON DISEASE. Pathologic features include neuronal loss and gliosis concentrated in the MESENCEPHALON; SUBTHALAMUS; and HYPOTHALAMUS. (From Adams et al., Principles of Neurology, 6th ed, p754)

Poliomyelitis - An acute infectious disease of humans, particularly children, caused by any of three serotypes of human poliovirus (POLIOVIRUS). Usually the infection is limited to the gastrointestinal tract and nasopharynx, and is often asymptomatic. The central nervous system, primarily the spinal cord, may be affected, leading to rapidly progressive paralysis, coarse FASCICULATION and hyporeflexia. Motor neurons are primarily affected. Encephalitis may also occur. The virus replicates in the nervous system, and may cause significant neuronal loss, most notably in the spinal cord. A rare related condition, nonpoliovirus poliomyelitis, may result from infections with nonpoliovirus enteroviruses. (From Adams et al., Principles of Neurology, 6th ed, pp764-5)

RNA - A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)

Subacute Sclerosing Panencephalitis - A rare, slowly progressive encephalitis caused by chronic infection with the MEASLES VIRUS. The condition occurs primarily in children and young adults, approximately 2-8 years after the initial infection. A gradual decline in intellectual abilities and behavioral alterations are followed by progressive MYOCLONUS; MUSCLE SPASTICITY; SEIZURES; DEMENTIA; autonomic dysfunction; and ATAXIA. DEATH usually occurs 1-3 years after disease onset. Pathologic features include perivascular cuffing, eosinophilic cytoplasmic inclusions, neurophagia, and fibrous gliosis. It is caused by the SSPE virus, which is a defective variant of MEASLES VIRUS. (From Adams et al., Principles of Neurology, 6th ed, pp767-8)

Theilovirus - A species of CARDIOVIRUS which contains three strains: Theiler's murine encephalomyelitis virus, Vilyuisk human encephalomyelitis virus, and Rat encephalomyelitis virus.

Visna - Demyelinating leukoencephalomyelitis of sheep caused by the VISNA-MAEDI VIRUS. It is similar to but not the same as SCRAPIE.

West Nile Fever - A mosquito-borne viral illness caused by the WEST NILE VIRUS, a FLAVIVIRUS and endemic to regions of Africa, Asia, and Europe. Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. The disease may occasionally be fatal or leave survivors with residual neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13; Lancet 1998 Sep 5;352(9130):767-71)

Instructional Notations

Includes

This note appears immediately under a three character code title to further define, or give examples of, the content of the category.

• acute ascending myelitis
• meningoencephalitis
• meningomyelitis

Type 1 Excludes

A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

• encephalopathy NOS G93.40

Type 2 Excludes

A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

• 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