What is meningeal syndrome?

Meningeal syndrome refers to a group of symptoms caused by irritation, inflammation, or infection of the meninges, the protective membranes covering the brain and spinal cord. Symptoms typically include severe headache, neck stiffness, photophobia (sensitivity to light), and other neurological signs.

How is meningeal syndrome diagnosed?

Diagnosis typically involves clinical evaluation of symptoms and signs, lumbar puncture for cerebrospinal fluid (CSF) analysis, which can identify infectious agents and inflammatory markers, and imaging studies like CT or MRI scans to rule out other causes of symptoms.

ADD-ONS / GENERAL NEUROLOGY

Meningeal Syndrome

David Goldemund M.D.
Updated on 10/08/2024, published on 06/08/2024

Definition

meningeal syndrome is a clinical constellation of signs and symptoms resulting from irritation of the meninges by various pathological processes (bleeding, inflammatory, or neoplastic processes)
meningism (pseudomeningitis) refers to a clinical syndrome characterized by signs and symptoms of meningeal irritation without actual inflammation of the meninges

Meninges

the meninges are three layers of protective tissue that surround the brain and spinal cord
- pia mater – the innermost layer that is formed by a thin, translucent membrane that closely adheres to the brain and spinal cord. It follows the contours of these structures, dipping into the sulci and fissures of the brain.
- arachnoid mater – the middle layer, which is a delicate, web-like structure that helps cushion the central nervous system; between pia and arachnoid mater is the subarachnoid space filled with cerebrospinal fluid (CSF)
  - this fluid circulates nutrients and chemicals filtered from the blood and also provides cushioning
- dura mater – the outermost layer, attached to the inside of the skull; it contains veins; between the dura mater and the arachnoid is subdural space and the space between the dura mater and the bone is called epidural space
meninges perform critical functions
- protect from impact and injury
- contain and circulate cerebrospinal fluid
- form a barrier against the spread of infection

Etiology

Noninfectious

subarachnoid hemorrhage (sudden severe headache, xanthochromia in CSF)
autoimmune diseases:
- sarcoidosis (Vahabi, 2011)
- systemic lupus erythematosus (SLE) with CNS involvement (Mahmeed, 2020)
carcinomatous or lymphomatous meningitis
- it is also termed: meningeal metastatic disease, leptomeningeal meningitis, leptomeningeal carcinomatosis, leptomeningeal metastasis, or neoplastic meningitis
- most common causes: breast cancer (5-8% of patients), lung cancer (particularly non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC)), melanoma, gastrointestinal cancers, lymphomas and leukemias (especially non-Hodgkin’s lymphoma and acute lymphoblastic leukemia)
drug-induced aseptic meningitis (DIAM)
- nonsteroidal anti-inflammatory drugs (NSAIDs) (Mirzaei, 2021)
  - ibuprofen is the most common cause; it appears to be an immunologically mediated hypersensitivity mechanism
- intravenous immunoglobulins, etc. (Kretowska-Grunwald, 2022)

Infectious

bacterial meningitis (Streptococcus pneumoniae, Neisseria meningitis, Haemophilus influenzae, TBC, Listeria monocytogenes)
viral meningitis (enterovirus, HSV, VZV, HIV)
fungal meningitis (Cryptococcus neoformans, Histoplasma capsulatum
parasitic meningitis (Naegleria fowleri, Taenia solium)

Clinical Presentation

General hyperesthesia (sensory and reflex-induced muscle spasms), often accompanied by symptoms of intracranial hypertension

hypersensitivity (photophobia, phonophobia, sensitive trigeminal nerve endings, cutaneous hyperesthesia)
headache
- often severe, generalized, and persistent
- occurs due to irritation of sensory nerves, meninges, and possibly intracranial hypertension)
muscle stiffness – especially affecting the neck (nuchal rigidity), back, abdominal, and masticatory muscles as a reflex antalgic defense contraction → meningeal signs
nausea, vomiting
fever (common in infectious causes, may also occur with SAH)
qualitative and quantitative consciousness disturbance

Diagnostic evaluation

history
- onset, duration, and progression of symptoms (headache, fever, neck stiffness)
- recent infections, travel history, vaccination status
- history of head trauma, immunocompromised state, or recent intracranial or intraspinal surgery
clinical examination
- meningeal signs
- neurological examination (assess for focal deficits, altered mental status, cranial nerve involvement)
- general examination (signs of systemic infection or other sources of sepsis)
blood tests:
- C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
- complete blood count (CBC)
  - leukocytosis may indicate infection
- blood cultures
imaging methods
- CT (rules out SAH, space-occupying lesion, etc.)
- MRI with gadolinium for suspected encephalitis or to identify meningeal enhancement

lumbar puncture with CSF analysis
- opening pressure
- cell count (pleocytosis in infection)
- glucose (hypoglycorrhachia in bacterial meningitis)
- protein levels (elevated in meningitis)
- gram stain and culture
- polymerase chain reaction (PCR) to detect viral pathogens
- india ink stain or cryptococcal antigen if cryptococcal meningitis is suspected

Meningeal signs

assessment of nuchal rigidity: if positive, passive flexion of the patient’s neck causes pain and resistance (also check rotation and lateroflexion to rule out cervical-cranial syndrome)
Kernig sign: passive extension of the knee, while the leg is flexed at the hip in a supine patient, causes pain
Brudzinki sign: passive neck flexion causes reflex knee flexion in the supine position
Amos sign (tripod sign) – observed when a patient, while attempting to sit up from a prone position, supports themselves on their hands placed behind their back to relieve tension on the meninges; the patient exhibits discomfort while trying to sit up without using their hands for support

Meningism/pseudomeningeal syndrome

meningism, also known as pseudomeningitis, refers to a clinical syndrome characterized by signs and symptoms of meningeal irritation without actual meningeal inflammation (negative CSF, etc.)

causes:
- intracranial hypo- and hypertension
- cervicocranial syndrome (significantly restricted head rotation and tilting)
- expansive intracranial processes (additional features such as focal symptoms and slowed psychomotor speed are common)
- in advanced meningeal syndrome, spasms may affect the abdominal wall muscles – beware of confusion with a peritoneal syndrome
- migraines – severe migraine headaches can sometimes present with neck stiffness and photophobia, resembling meningeal signs
- medications – certain medications, such as the chemotherapy drug cytarabine, can cause chemical meningitis, which presents similarly to infectious meningitis but without infection
- other infections – viral encephalitis or severe systemic infections without actual meningitis