Prognosis for individuals suffering from brain abscess is guarded to poor as the blood-brain barrier is impermeable to most antibiotics. In many cases drainage is impossible due to the location of the abscess within the brain. Cases of fungal brain abscess carry a grave prognosis.
Meningitis
Meningitis is defined as inflammation of the meninges.
It is usually caused by bacterial infections such as E. coli and Salmonella spp. or viral infections like EEE, WEE, VEE and West Nile virus. These infectious agents enter the meninges through the blood vessels of the sub-arachnoid space, where they trigger a vigorous immune response. Microglia and astrocytes release large quantities of which increase the permeability of the blood-brain barrier to leukocytes and exudate. The leukocytes attack the walls of the blood vessels of the meninges, and also cause damage to the meninges tissue itself, resulting in further inflammation of the meninges and increased intracranial pressure. Damage to the blood vessels triggers the clotting cascade resulting in the formation of multiple, tiny blood clots throughout the vasculature of the meninges. Individuals with open skull fractures are at a higher risk of developing bacterial meningitis, while those with systemic infection, septicemia or who are immunocompromised have an increased risk of developing meningitis of either type. Generally, meningitis is haematogenous in origin, but transmission of pathogens can be environmental if there is an open skull fracture. The clinical presentation of meningitis includes systemic signs, dementia, head pressing, circling, gait abnormalities or ataxia, CN deficits including head tilt, blindness and facial paralysis, stiffness in the neck, disorientation, recumbency, seizures, coma and death. Signs are generally progressive, but may escalate rapidly to seizures, coma and death.
Diagnosis is made through blood and through culture from either of these fluids.
analysis and the etiological agent is isolated
Treatment includes IV antibiotics, corticosteroids, anticonvulsant medications, IV DMSO, and supportive care such as IV fluids, padded stalls, catheters and slings. Prognosis is guarded to poor for horses with meningitis. Recovery is generally slow, and the individual may not return to the previous level of performance.
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