What causes meningeal syndrome?

Meningeal syndrome can be caused by an inflammatory process. Caused by various microbial flora (meningitis, meningoencephalitis) or non-inflammatory lesions of the brain membranes. In these cases, the term "meningism" is used. In case of inflammation, the etiologic factor may be bacteria (bacterial meningitis), viruses (viral meningitis), fungi (fungal meningitis), protozoa (toxoplasmosis, amoeba).

The main causes of meningeal syndrome:

I. Meningitis (meningeal + cerebrospinal fluid syndrome).

II. Meningism (pseudomeningitis):

A) Caused by physical causes:

• Insolation.
• Water intoxication.
• Post-puncture syndrome.

C) Caused by somatic causes:

• Intoxication (uremia, alcohol).
• Infectious diseases
• (influenza, salmonellosis, dysentery and others).
• "Hypertonic crisis" (transient ischemic attacks in arterial hypertension) and acute hypertensive encephalopathy.
• Hypoparathyroidism.

C) Caused by neurological diseases (swelling and irritation of the membranes):

• Subarachnoid hemorrhage.
• Hypertensive-occlusive syndrome with volumetric processes, vascular accidents, brain traumas, carcinomatosis and sarcoidosis of membranes.
• Pseudotumor (Pseudotumor cerebri).
• Radiation damage.

D) Caused by other (rare) causes: severe allergies, etc.

III. Pseudo-meningeal syndrome (pseudo-Kernig with processes in the frontal lobe of different nature, increased muscle tone of the extensor muscles of the neck with some neurological, vertebrogenic and even mental diseases).

I. Meningeal syndrome

Meningeal syndrome (a syndrome of irritation of the meninges) is most often caused by an inflammatory process in the membranes of the brain in bacterial or viral infections (bacterial or viral meningitis). But it can also develop as a reaction to a foreign substance in the subarachnoid space (subarachnoid hemorrhage, administration of medications, contrast material, spinal anesthetics). It is also characteristic of aseptic meningitis (meningeal syndrome of pleocytosis without bacterial or fungal infection) and meningism (syndrome of irritation of meninges without pleocytosis).

The syndrome of irritation of the meninges includes the following symptoms: headaches with stiffness and pain in the neck; irritability; hyperesthesia of the skin; photophobia; phonophobia; fever and other manifestations of infection; nausea and vomiting, confusion, delirium, epileptic seizures, to whom. Full meningeal syndrome also includes characteristic changes in cerebrospinal fluid (liquor syndrome) and the following signs of irritation of the meninges: rigidity of the neck muscles; resistance to passive extension of the legs; a symptom of Kernig (the leg does not unbend at the knee joint more than 135 °); Bikel's symptom (Vikele) is an analogue of Kernig's symptom on the hands; the upper symptom of Brudzinsky; the lower symptom of Brudzinsky; reciprocal contralateral symptom of Brudzinsky on legs; cheek symptom of Brudzinsky; Symphysis symptom of Brudzinsky; Guillain's symptom; the phenomenon of Edelman's thumb.

Two-thirds of patients with bacterial meningitis have a triad of symptoms: fever, neck stiffness and mental disturbances. It is useful to remember that the rigidity of neck muscles is often absent in children younger than 6 months. Cervical spondylosis in the elderly makes it difficult to assess the rigidity of the neck muscles.

Investigation of cerebrospinal fluid is the only way to confirm the diagnosis of meningitis and determine the pathogen. For differential diagnostic purposes (to exclude abscess, tumor, etc.), CT or MRI is used. In the cerebrospinal fluid, cytosis, protein and sugar content are investigated, bacteriological (and virologic) and serological tests are performed. Mandatory microscopic examination of cerebrospinal fluid. Edema of the optic disc is observed only in 4% of cases of bacterial meningitis in adults. Somatic examination often gives the key to understanding the nature of meningitis. Diagnosis and treatment of meningitis do not suffer procrastination.

Differential diagnosis of bacterial meningitis should include viral infections of the central nervous system, craniocerebral trauma, subdural hematoma, brain abscess, febrile seizures in children, sepsis, Reye's syndrome, metabolic encephalopathy, acute hypertensive encephalopathy, intoxications, subarachnoid hemorrhage, carcinomatous meningitis.

II. Meningism

Meningism is a syndrome of irritation of the meninges, in which there is no change in cerebrospinal fluid (pseudomeningitis).

Excessive insolation can lead to a thermal shock, which is characterized by hyperemia and edema of the membranes and brain tissue. Heavy forms of heat stroke begin suddenly, sometimes apoplectically. Consciousness can be broken from mild degrees to coma; possibly psychomotor agitation or psychotic disorders, epileptic seizures; meningeal syndrome. Body temperature rises to 41-42 ° and higher. Thermal shock usually occurs during the period of maximum heat exposure and only in rare cases in the period after overheating.

Water intoxication occurs when the water is introduced into the body excessively (with a relative deficiency of electrolytes), especially against the background of insufficient release of fluid (oliguria with adrenal insufficiency, kidney disease, use of vasopressin or its hypersecretion after trauma or surgery). In blood plasma, the water content increases; there is hyponatremia and hypokalemia; characteristic of hypoosmolarity of blood. Developed apathy, deafness, headache, krumpi, meningeal syndrome. Characteristic is the appearance of nausea, which is worse after drinking fresh water, and vomiting that does not bring relief. In severe cases, edema of the lungs, ascites, hydrothorax develops.

Post-puncture syndrome is sometimes manifested by the symptoms of mild meningism, which usually goes off on its own in a few days.

The somatic causes of meningism are most often associated with endogenous (uremia) or exogenous intoxication (alcohol or its surrogates), intoxication with infectious diseases (influenza, salmonella, dysentery, etc.). Transient ischemic attack in patients with hypertensive disease is rarely accompanied by symptoms of irritation of the meninges. Acute hypertensive encephalopathy develops within a few hours and is manifested by headache, nausea, vomiting, meningism, impaired consciousness on a background of high blood pressure (diastolic pressure 120-150 mm Hg pillar and above) and symptoms of cerebral edema (CT, MRI, edema of the optic nerve). Focal neurological symptoms are not characteristic. Disorders of consciousness vary from mild confusion to coma. Differential diagnosis is performed with subarachnoid hemorrhage, acute alcohol intoxication and other conditions.

Hypoparathyroidism reflects a deficiency in parathyroid gland function and is characterized by a decrease in calcium content in the blood. Causes: surgical intervention on the thyroid gland (secondary hypoparathyroidism), autoimmune thyroiditis Hashimoto and Addison's pernicious anemia. Among the diverse neurological manifestations of hypocalcemia in hypoparathyroidism (tetany with muscular spasms and laryngospasm, myopathy, impaired consciousness, psychotic disorders, hemichorea, intracranial calcification and even epileptic seizures), an increase in intracranial pressure with edema of the optic nerve discs is described. Possible development of pseudotumor cerebri. Clinical manifestations of recent complications of hypoparathyroidism may include sometimes mild symptoms of irritation of the meninges.

Such neurological diseases as subarachnoid hemorrhage, as well as hypertensive-occlusive syndrome with volumetric processes, vascular accidents, brain traumas, carcinomatosis and sarcoidosis of the membranes are accompanied by a distinctly expressed meningeal syndrome. These diseases are usually recognized clinically, or through neuroimaging and obscheomatic examination.

Radiation damage to the brain most often develops in connection with the treatment of brain tumors and is manifested by transient deterioration of the symptoms of the underlying disease (tumor), epileptic seizures and signs of increased intracranial pressure, which is presumably associated with cerebral edema (although the latter is not confirmed by MRI data). Sometimes symptoms of meningism (an early complication of therapy) may be present. Increased intracranial pressure is sometimes observed against the background of late (progressive dementia, ataxia, urinary incontinence, panhypopituitarism) complications (3 months to 3 years after therapy) of radiation therapy. Late complications are associated mainly with the development of multifocal necrosis zones in the brain tissue.

III. Pseudomeningeal syndrome

Pseudomeningeal syndrome is most often discussed in connection with an increase in tonus in the supineus muscles in the absence of the true symptoms of irritation of the meninges. Such a symptom may be a manifestation of paratonism (gegenchalten, antagonism) in frontal lesions of different nature (metabolic encephalopathy, diffuse cerebral atrophy, vascular encephalopathy in arterial hypertension), plastic muscle toning (Parkinsonism, progressive supranuclear palsy, other dystonic syndromes, stiffness), catalepsy at a schizophrenia, diseases of a cervical department of a backbone or vertebrogenic muscular-tonic syndromes. Difficult unbending of the head in these conditions is observed in the context of other expressed neurological, somatic and psychiatric disorders, which must be taken into account when interpreting this symptom.

For differential diagnosis between inflammatory lesions of the membranes of the brain and meningism, it is necessary to study the cerebrospinal fluid obtained with spinal puncture.

Additional methods include examination of the fundus, radiography of the skull, echoencephalography (in children up to one year - sonography), EEG, CT and MRI of the brain. If the patient has a meningeal syndrome, the following algorithm of action is advisable.

Pathogenesis of meningeal syndrome

Meningeal syndrome can be caused by the inflammatory process and vascular disorders in the membranes of the brain, cerebrospinal fluid hypertension.