2026 ICD-10-CM Diagnosis Code G03.9Meningitis, unspecified

AHRQ’s CCSR groups this code into broader clinical categories.

• Coccidioidal Meningitis

  meningitis caused by a fungus of the genus coccidioides, endemic to the southwestern united states, south-central washington state, and parts of mexico and central and south america.

• Malaria, Cerebral

  a condition characterized by somnolence or coma in the presence of an acute infection with plasmodium falciparum (and rarely other plasmodium species). initial clinical manifestations include headaches; seizures; and alterations of mentation followed by a rapid progression to coma. pathologic features include cerebral capillaries filled with parasitized erythrocytes and multiple small foci of cortical and subcortical necrosis. (from adams et al., principles of neurology, 6th ed, p136)

• Meningeal Carcinomatosis

  primary or secondary neoplasm in the arachnoid or subarachnoid space. it appears as a diffuse fibrotic thickening of the meninges associated with variable degrees of inflammation.

• Meningism

  a condition characterized by neck stiffness, headache, and other symptoms suggestive of meningeal irritation, but without actual inflammation of the meninges (meningitis). spinal fluid pressure may be elevated but spinal fluid is normal. (dejong, the neurologic examination, 4th ed, p673)

• Meningitis

  inflammation of the coverings of the brain and/or spinal cord, which consist of the pia mater; arachnoid; and dura mater. infections (viral, bacterial, and fungal) are the most common causes of this condition, but subarachnoid hemorrhage (hemorrhages, subarachnoid), chemical irritation (chemical meningitis), granulomatous conditions, neoplastic conditions (carcinomatous meningitis), and other inflammatory conditions may produce this syndrome. (from joynt, clinical neurology, 1994, ch24, p6)

• Meningitis, Aseptic

  a syndrome characterized by headache, neck stiffness, low grade fever, and csf lymphocytic pleocytosis in the absence of an acute bacterial pathogen. viral meningitis is the most frequent cause although mycoplasma infections; rickettsia infections; diagnostic or therapeutic procedures; neoplastic processes; septic perimeningeal foci; and other conditions may result in this syndrome. (from adams et al., principles of neurology, 6th ed, p745)

• Meningitis, Bacterial

  bacterial infections of the leptomeninges and subarachnoid space, frequently involving the cerebral cortex, cranial nerves, cerebral blood vessels, spinal cord, and nerve roots.

• Meningitis, Cryptococcal

  meningeal inflammation produced by cryptococcus neoformans, an encapsulated yeast that tends to infect individuals with acquired immunodeficiency syndrome and other immunocompromised states. the organism enters the body through the respiratory tract, but symptomatic infections are usually limited to the lungs and nervous system. the organism may also produce parenchymal brain lesions (torulomas). clinically, the course is subacute and may feature headache; nausea; photophobia; focal neurologic deficits; seizures; cranial neuropathies; and hydrocephalus. (from adams et al., principles of neurology, 6th ed, pp721-2)

• Meningitis, Escherichia coli

  a form of gram-negative meningitis that tends to occur in neonates, in association with anatomical abnormalities (which feature communication between the meninges and cutaneous structures) or as opportunistic infections in association with immunologic deficiency syndromes. in premature neonates the clinical presentation may be limited to anorexia; vomiting; lethargy; or respiratory distress. full-term infants may have as additional features fever; seizures; and bulging of the anterior fontanelle. (from menkes, textbook of child neurology, 5th ed, pp398-400)

• Meningitis, Fungal

  meningitis caused by fungal agents which may occur as opportunistic infections or arise in immunocompetent hosts.

• Meningitis, Haemophilus

  infections of the nervous system caused by bacteria of the genus haemophilus, and marked by prominent inflammation of the meninges. haemophilus influenzae type b is the most common causative organism. the condition primarily affects children under 6 years of age but may occur in adults.

• 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)

• Meningitis, Meningococcal

  a fulminant infection of the meninges and subarachnoid fluid by the bacterium neisseria meningitidis, producing diffuse inflammation and peri-meningeal venous thromboses. clinical manifestations include fever, nuchal rigidity, seizures, severe headache, petechial rash, stupor, focal neurologic deficits, hydrocephalus, and coma. the organism is usually transmitted via nasopharyngeal secretions and is a leading cause of meningitis in children and young adults. organisms from neisseria meningitidis serogroups a, b, c, y, and w-135 have been reported to cause meningitis. (from adams et al., principles of neurology, 6th ed, pp689-701; curr opin pediatr 1998 feb;10(1):13-8)

• Meningitis, Pneumococcal

  an acute purulent infection of the meninges and subarachnoid space caused by streptococcus pneumoniae, most prevalent in children and adults over the age of 60. this illness may be associated with otitis media; mastoiditis; sinusitis; respiratory tract infections; sickle cell disease (anemia, sickle cell); skull fractures; and other disorders. clinical manifestations include fever; headache; neck stiffness; and somnolence followed by seizures; focal neurologic deficits (notably deafness); and coma. (from miller et al., merritt's textbook of neurology, 9th ed, p111)

• Meningitis, Viral

  viral infections of the leptomeninges and subarachnoid space. togaviridae infections; flaviviridae infections; rubella; bunyaviridae infections; orbivirus infections; picornaviridae infections; orthomyxoviridae infections; rhabdoviridae infections; arenaviridae infections; herpesviridae infections; adenoviridae infections; jc virus infections; and retroviridae infections may cause this form of meningitis. clinical manifestations include fever, headache, neck pain, vomiting, photophobia, and signs of meningeal irritation. (from joynt, clinical neurology, 1996, ch26, pp1-3)

• Tuberculosis, Meningeal

  a form of bacterial meningitis caused by mycobacterium tuberculosis or rarely mycobacterium bovis. the organism seeds the meninges and forms microtuberculomas which subsequently rupture. the clinical course tends to be subacute, with progressions occurring over a period of several days or longer. headache and meningeal irritation may be followed by seizures, cranial neuropathies, focal neurologic deficits, somnolence, and eventually coma. the illness may occur in immunocompetent individuals or as an opportunistic infection in the acquired immunodeficiency syndrome and other immunodeficiency syndromes. (from adams et al., principles of neurology, 6th ed, pp717-9)

• Subdural Effusion

  leakage and accumulation of cerebrospinal fluid in the subdural space which may be associated with an infectious process; craniocerebral trauma; brain neoplasms; intracranial hypotension; and other conditions.

• Arachnoiditis

  acute or chronic inflammation of the arachnoid membrane of the meninges most often involving the spinal cord or base of the brain. this term generally refers to a persistent inflammatory process characterized by thickening of the arachnoid membrane and dural adhesions. associated conditions include prior surgery, infections, trauma, subarachnoid hemorrhage, and chemical irritation. clinical features vary with the site of inflammation, but include cranial neuropathies, radiculopathies, and myelopathies. (from joynt, clinical neurology, 1997, ch48, p25)

• Opportunistic Infections

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

• Grade 2 Arachnoiditis, CTCAE|Grade 2 Arachnoiditis

  moderate symptoms; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

• Grade 3 Arachnoiditis, CTCAE|Grade 3 Arachnoiditis

  severe symptoms; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

• Spinal Arachnoiditis

  a chronic adhesive arachnoiditis in the spinal arachnoid, with root and spinal cord symptoms similar to those caused by pressure from a tumor.

• Arachnoiditis

  inflammation of the arachnoid membrane and adjacent subarachnoid space.

• Arachnoiditis, CTCAE|Arachnoiditis|Arachnoiditis

  a disorder characterized by inflammation of the arachnoid membrane and adjacent subarachnoid space.

• Grade 1 Arachnoiditis, CTCAE|Grade 1 Arachnoiditis

  mild symptoms

• Grade 2 Arachnoiditis, CTCAE|Grade 2 Arachnoiditis

  moderate symptoms; limiting instrumental adl

• Grade 3 Arachnoiditis, CTCAE|Grade 3 Arachnoiditis

  severe symptoms; limiting self care adl

• Grade 4 Arachnoiditis, CTCAE|Grade 4 Arachnoiditis

  life-threatening consequences; urgent intervention indicated

• Grade 5 Arachnoiditis, CTCAE|Grade 5 Arachnoiditis

  death

Meningitis

Meningitis is inflammation of the thin tissue that surrounds the brain and spinal cord, called the meninges. There are several types of meningitis. The most common is viral meningitis. You get it when a virus enters the body through the nose or mouth and travels to the brain. Bacterial meningitis is rare but can be deadly.

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