neurologic disorders
Helminthic Brain Infections
Neurocysticercosis
(See also Cysticercosis .) Among about 20 helminths that can cause neurologic disorders, the pork tapeworm Taenia Solium (Pork Tapeworm) Infection and Cysticercosis causes by far the most cases in the Western Hemisphere. The resulting disorder is neurocysticercosis. After a person eats food contaminated with the worm’s eggs, larvae migrate to tissues, including the brain, spinal cord, and cerebrospinal fluid (CSF) pathways, and form cysts. Cyst diameter rarely exceeds 1 cm in neural parenchyma but may exceed 5 cm in CSF spaces. Older cysts frequently calcify. Brain parenchymal cysts cause few symptoms until death of the worms triggers local inflammation, gliosis, and edema, causing seizures (most commonly), cognitive or focal neurologic deficits, or personality changes. Larger cysts in CSF pathways may cause obstructive hydrocephalus. Cysts may rupture into CSF, inducing acute or subacute eosinophilic meningitis. Without treatment, neurocysticercosis can cause death; cause of death includes encephalitis, meningitis, hydrocephalus, and untreated seizures. Neurocysticercosis is suspected in patients who live in or have come from developing countries and who have eosinophilic meningitis or unexplained seizures, cognitive or focal deficits, or personality changes. It is suggested by multiple calcified cystic lesions seen on CT or MRI; a contrast agent may enhance the lesions. Diagnosis requires serum and CSF serologic tests and occasionally cyst biopsy. Antihelminthic drugs are first-line therapy.Albendazole(7.5 mg/kg orally every 12 hours for 8 to 30 days; maximum daily dose, 800 mg) is the antihelminthic drug of choice. Alternatively,praziquantel20 to 33 mg/kg orally 3 times a day may be given for 30 days.Dexamethasone8 mg IV or orally once a day for the first 2 to 4 days may lessen the acute inflammatory response as the worms die. If antihelminthic therapy results in the death of many organisms, the brain may swell significantly in patients with a large number of cysts, and antihelminthic therapy may not help patients with a single cyst. Treatment must be carefully individualized. Short- or long-term treatment with Antiseizure Medications may be required. Surgical excision of cysts and ventricular shunts may also be required. 