Chronic inflammation of the meninges (pia, arachnoid, and dura) can produce profound neurologic disability and may be fatal if not successfully treated. Chronic meningitis is diagnosed when a characteristic neurologic syndrome exists for >4 weeks and is associated with a persistent inflammatory response in the cerebrospinal fluid (CSF) (white blood cell count >5/μL). The causes are varied, and appropriate treatment depends on identification of the etiology. Five categories of disease account for most cases of chronic meningitis: (1) meningeal infections, (2) malignancy, (3) autoimmune inflammatory disorders, (4) chemical meningitis, and (5) parameningeal infections.
Neurologic manifestations of chronic meningitis (Table 37-1) are determined by the anatomic location of the inflammation and its consequences. Persistent headache with or without a stiff neck, hydrocephalus, cranial neuropathies, radiculopathies, and cognitive or personality changes are the cardinal features. These can occur alone or in combination. When they appear in combination, widespread dissemination of the inflammatory process along CSF pathways has occurred. In some cases, the presence of an underlying systemic illness points to a specific agent or class of agents as the probable cause. The diagnosis of chronic meningitis is usually made when the clinical presentation prompts the physician to examine the CSF for signs of inflammation. CSF is produced by the choroid plexus of the cerebral ventricles, exits through narrow foramina into the subarachnoid space surrounding the brain and spinal cord, circulates around the base of the brain and over the cerebral hemispheres, and is resorbed by arachnoid villi projecting into the superior sagittal sinus. CSF flow provides a pathway for rapid spread of infectious and other infiltrative processes over the brain, spinal cord, and cranial and spinal nerve roots. Spread from the subarachnoid space into brain parenchyma may occur via the arachnoid cuffs that surround blood vessels that penetrate brain tissue (Virchow-Robin spaces).
TABLE 37-1SYMPTOMS AND SIGNS OF CHRONIC MENINGITIS |Favorite Table|Download (.pdf) TABLE 37-1 SYMPTOMS AND SIGNS OF CHRONIC MENINGITIS
|SYMPTOM ||SIGN |
|Chronic headache ||± Papilledema |
|Neck or back pain/stiffness ||Brudzinski’s or Kernig’s sign of meningeal irritation |
|Change in personality ||Altered mental status—drowsiness, inattention, disorientation, memory loss, frontal release signs (grasp, suck, snout), perseveration |
|Facial weakness ||Peripheral seventh CN paresis |
|Double vision ||Paresis of CNs III, IV, VI |
|Diminished vision ||Papilledema, optic atrophy |
|Hearing loss ||Eighth CN paresis |
|Arm or leg weakness ||Myelopathy or radiculopathy |
|Numbness in arms or legs ||Myelopathy or radiculopathy |
|Urinary retention/incontinence || |
Myelopathy or radiculopathy
Frontal lobe dysfunction (hydrocephalus)
|Clumsiness ||Ataxia |
Nociceptive nerve fibers of the meninges are stimulated by the inflammatory process, resulting in headache, neck pain, or back pain. Obstruction of CSF pathways at the foramina or arachnoid villi may produce hydrocephalus and symptoms of raised intracranial pressure (ICP), including headache, vomiting, apathy or drowsiness, gait instability, papilledema, visual loss, ...