Otogenic meningitis is acute purulent inflammation of the arachnoid and pia mater caused by complications of otitis media. Localized meningitis, also known as subdural abscess, is purulent lesions confined to the arachnoid and pia mater in a specific area.
Clinical manifestations
High fever, headache, and projectile vomiting are the primary symptoms. The onset may include rigors and fever, with body temperature reaching 39°C - 40°C. In the late stages, involvement of the thermoregulatory center can cause the temperature to rise to 41°C. Pulse rate is rapid and corresponds to changes in body temperature. Blood tests show leukocytosis with an increase in polymorphonuclear leukocytes.
Severe headache is with no fixed location, often diffuse, but later more pronounced in the occipital region. Projectile vomiting occurs, which is unrelated to food intake. Children may experience diarrhea and convulsions. Neurological and psychiatric symptoms, such as irritability, hypersensitivity to stimuli, restlessness, and seizures, may also occur. Severe cases may present with drowsiness, delirium, or coma. Brain herniation may cause cranial nerve palsy, and in the late stages, Cheyne-Stokes respiration, urinary and fecal incontinence, and respiratory or circulatory failure leading to death.
Resistance or stiffness in the neck, and even opisthotonos, are present, and in severe cases, Kernig's sign and Brudzinski's sign are positive. If the pyramidal tract is involved, pyramidal tract signs, such as reduced superficial reflexes (e.g., abdominal reflex, cremasteric reflex) and hyperactive deep reflexes (e.g., knee reflex, Achilles reflex), may appear, along with pathological reflexes.
Cerebrospinal fluid (CSF) pressure is elevated, the fluid appears turbid, and cell count increases, predominantly polymorphonuclear leukocytes. Protein levels are elevated, while glucose and chloride levels are decreased. Bacterial cultures of CSF may be positive, with pathogens matching those cultured from middle ear pus.
Differential diagnosis
Epidemic meningitis
Differentiation can be made based on seasonal prevalence, history of outbreaks, and the presence of skin or mucosal petechiae and purpura. CSF culture typically identifies Neisseria meningitidis.
Tuberculous meningitis
This condition has a gradual onset and may be accompanied by tuberculosis lesions in other parts of the body. CSF analysis shows a predominance of lymphocytes, and acid-fast staining may detect Mycobacterium tuberculosis.
Benign recurrent meningitis
Mainly seen in children, this condition is characterized by mild symptoms and frequent recurrences. Epithelial cells and mononuclear cells may be present in the CSF.
Other types of meningitis
These include viral, protozoal, fungal, and syphilitic meningitis, which require careful differentiation based on clinical and laboratory findings.
Treatment
Adequate doses of broad-spectrum antibiotics can be administered to control the infection. Glucocorticoids may be used as appropriate.
Once the patient's general condition permits, emergency mastoidectomy can be performed to remove the lesion and adequate drainage should be ensured.
Water and electrolyte balance should be maintained. If intracranial pressure is elevated, measures should be taken to reduce it. Fluid intake should be carefully controlled, and hyperosmotic dehydrating agents may be used if necessary.