Which meninges are inflamed in meningitis

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Article: 'Learn from the lessons and don't forget them': identifying transferable lessons Meningitis -- see more articles. Find an Expert. Hydrocephalus and secondary vasculitis are main complications. Treatment has to be started as soon as possible, even without direct proof of the causative pathogenic agent, when clinical presentation and liquor results e.

Modern regimens comprise an antituberculostatic combination with Isoniazid, Rifampicin, Pyracinamid, or Ethambutol for at least 2 months or longer, when CSF is still positive for tuberculosis. In complicated cases intrathecal injection of streptomycin has been proposed as adjunctive treatment.

Steroids should be given to prevent secondary vasculitis. The typical imaging feature of TBM is enhancement of the basal cisterns and the corresponding leptomeninges caused by dense fibrinous exudate in the SAS Fig.

Interestingly, several studies have demonstrated that tuberculous meningitis is not only seen on contrast-enhanced T1-weighted images, but also on non-enhanced T1-weighted MT images, showing the inflamed meninges as distinct basal periparenchymal hyperintensity Kamra et al. This phenomenon is reported to be missing in patients with meningitis of other etiology; thus, visibility of the meninges on non-enhanced T1-weighted MT images has to be considered highly suggestive of tuberculous meningitis.

Yet, one has to keep in mind that formation of exudates requires a competent immune system in the host, as a consequence meningeal enhancement is often less pronounced or even missing in elderly patients and individuals with immune deficiency Srikanth et al.

Tuberculous meningitis. A year-old patient, with a history of intravenous drug abuse, presented with headache and abducent nerve palsy. Initial CT a showed hydrocephalus. MRI revealed basal meningitis with hyperintense exudates in the prepontine and basal cisterns and thick, linear leptomeningeal enhancement arrow in b, c around the pons, the pedunculi cerebelli, and within the quadrigeminal cistern.

Examination of the CSF confirmed tuberculous meningitis. Advantages of MRI are confirmed for patients with cranial nerve palsy: Imaging should always be performed in the axial and coronal plane using contrast-enhanced T1-weighted images with fat saturation to check for potential cranial nerve enhancement in the basal cisterns, the cavernous sinus, or the orbital cavities see also " Other causes of infectious and carcinomatous meningitis have to be considered for differential diagnosis.

While TBM causes predominantly basilar meningeal enhancement, bacterial meningitis affects more often the leptomeninges of the convexities. Furthermore, the combination of meningitis and parenchymal lesions suggests tuberculosis; however, some primary or metastatic tumors and some parasitic CNS infections e. Isolated inflammation of the meninges due to virus infection is rare. Most viruses cause encephalitis or meningoencephalitis described in detail in Chap.

Virus predominantly affecting leptomeningeal structures and the underlying cortex are HSV type 1, the most common causative agent for viral meningoencephalitis, and the arbovirus, that causes tick-borne meningoencephalitis TBME.

Additionally, parainfectious meningitis is a common finding in many systemic viral infections and after antiviral vaccination. Initial symptoms of viral meningitis are lassitude, fever, headache, and an altered sensorium.

Specific treatment with antiviral chemotherapeutics e. In many cases and in early stages of viral meningitis, neuroimaging reveals no abnormalities or only unspecific changes such as focal or diffuse brain edema and swelling, or signal abnormalities in the SAS due to an increased protein content of the CSF Fig. In the later stage of HSVmeningoencephalitis, leptomeningeal, and corticomedullary enhancement of the affected lobe may be visible; however, these changes follow the more specific changes of the disease with hyperintensity on T2-weighted and FLAIR images in limbic structures.

Pathological findings indicating the presence of encephalitis comprise hyperintensities on T2-weighted images in the thalami, brain stem, caudate nucleus, or the cerebellum. Viral meningitis. A year-old patient, who was admitted with fever, headache, and confused mental state.

Lumbar puncture revealed moderate pleocytosis, normal glucose, and lactate. Slightly hyperintense signal in the SAS of the sulci arrow in a, b , suggestive of protein-rich inflammatory exudates due to viral infection. Pathological enhancement of the meninges is absent c. In cases of isolated viral meningitis, other infectious and neoplastic diseases, especially bacterial meningitis, have to be excluded. The diagnosis is made by testing of the CSF. In case of HSV meningoencephalitis, differential diagnosis includes paraneoplastic limbic encephalitis, ischemia, infiltrating neoplasm, other encephalitides e.

Fungal infections of the CNS are most frequent in immunocompromised patients with AIDS, long-lasting diabetes mellitus, or after organ or bone marrow transplantation. Fungal hyphae e. The most common fungal infection of the CNS is cryptococcal meningoencephalitis, followed by aspergillosis and candidiasis. Cryptococcal meningoencephalitis manifests weeks after asymptomatic lung infection with clinical symptoms of basal meningitis, cranial nerve palsy, and hydrocephalus.

The diagnosis is made through direct confirmation of the fungus in the CSF. Aspergillus may reach the CNS via hematogenous spread or through direct invasion from sinunasal aspergillosis. The infection manifests predominantly with solitary or multiple brain abscess or granulomata, less often with meningitis or ventriculitis. Mortality of CNS infection with Aspergillus is extremely high. Hydrocephalus is found more often in immunocompetent patients as arachnoid reactions with exudates in the basal cisterns often do not manifest in immunocompromised individuals.

Generally, fungal meningitis may cause subarachnoid hyperintensity on DWI, predominantly around the frontal lobe Kawaguchi et al. Imaging features of Aspergillus meningeal infection comprise pachymeningeal enhancement nearby the affected nasal sinus or the orbit; typically, bony structures are involved in the inflammatory process.

As laboratory findings of fungal infection do not always confirm the causative pathogen, knowledge of neuroradiological appearance of aspergillosis is helpful for early diagnosis see also " Other infectious and neoplastic diseases, especially bacterial meningitis and TBM, have to be excluded.

Fungal meningitis often causes a thicker and lumpier meningeal enhancement than bacterial or viral meningitis. In case of pachymeningeal enhancement and involvement of the skull base, neoplasms arising from the nasopharynx of the sinus have to be ruled out. Syphilis is a curable sexually transmitted disease caused by the spirochete Treponema pallidum.

The use of penicillin has reduced the incidence of syphilis during the past century; however, the trend has reversed since the s due to the exchange of sex for drugs, unprotected sex, and the number of people with multiple sexual partners.

Neurosyphilis Neurolues is classified into four syndromes: syphilitic meningitis; meningovascular syphilis; as well as parenchymatous and gummatous neurosyphilis, these latter ones ending in general paresis and tabes dorsalis. Syphilitic meningitis occurs usually in the second stage of the disease within the first 2 years after infection. It is thought to be the consequence of direct meningeal inflammation due to small-vessel arteritis.

Patients present with headache, meningeal irritation, and cranial nerve involvement, especially the optic nerve, facial nerve, and the vestibulocochlear nerve. Meningovascular syphilis is assigned to the tertiary or late stage of syphilis.

If meningitis is caused by an infection, appropriate antimicrobial drugs such as antibiotics, antiviral drugs, or antifungal drugs are used.

If doctors suspect that meningitis is caused by bacteria or if people appear very ill, they treat the person with antibiotics immediately—without waiting for test results—because bacterial meningitis progresses rapidly and is life threatening.

People may also be given corticosteroids to reduce swelling in the brain. General measures may help relieve symptoms when meningitis is caused by conditions such as a viral infection or a reaction to a drug. When meningitis is mild, drinking plenty of fluids, resting, and taking over-the-counter OTC drugs can help relieve fever and pain.

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The Manual was first published in as a service to the community. Learn more about our commitment to Global Medical Knowledge. This site complies with the HONcode standard for trustworthy health information: verify here. Common Health Topics. Courtesy of. Test your knowledge. Bell palsy is sudden weakness or paralysis of the muscles on one side of the face due to malfunction of the seventh cranial nerve.

This nerve moves facial muscles, stimulates salivary and tear glands, detects tastes, and controls a muscle involved in hearing. Which of the following is often the first symptom of Bell palsy? More Content. Introduction to Meningitis By John E. Click here for the Professional Version. A spinal tap is done to obtain a sample of cerebrospinal fluid for analysis.

Dura mater outermost. Tissues Covering the Brain Within the skull, the brain is covered by three layers of tissue called the meninges. Infection with microorganisms such as bacteria, viruses, or fungi. A painful, stiff neck that makes lowering the chin to the chest difficult or impossible. Common bacteria or viruses that can cause meningitis can spread through coughing, sneezing, kissing, or sharing eating utensils, a toothbrush or a cigarette.

Meningococcal conjugate vaccine. The CDC recommends that a single dose be given to children ages 11 to 12, with a booster shot given at age If the vaccine is first given between ages 13 and 15, the booster is recommended between ages 16 and If the first shot is given at age 16 or older, no booster is necessary. This vaccine can also be given to children between the ages of 2 months and 10 years who are at high risk of bacterial meningitis or who have been exposed to someone with the disease.

It's also used to vaccinate healthy but previously unvaccinated people who have been exposed in outbreaks. Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. This content does not have an English version.

This content does not have an Arabic version. Overview Meningitis is an inflammation of the fluid and membranes meninges surrounding your brain and spinal cord.

Request an Appointment at Mayo Clinic. Meningitis Open pop-up dialog box Close. Meningitis Meningitis is an infection and inflammation of the fluid and three membranes meninges protecting your brain and spinal cord. Share on: Facebook Twitter. Show references Meningitis and encephalitis fact sheet. National Institute of Neurological Disorders and Stroke. Accessed Sept. Bacterial meningitis. Centers for Disease Control and Prevention.

Bartt R. Acute bacterial and viral meningitis. Continuum Lifelong Learning in Neurology. Viral meningitis.