Cysticercosis is a tissue infection caused by the young form of the pork tapeworm. People may have few or no symptoms for years. In some cases, particularly in Asia, solid lumps of between one and two centimetres may develop under the skin. After months or years these lumps can become painful and swollen and then resolve. A specific form called neurocysticercosis, which affects the brain, can cause neurological symptoms. In developing countries this is one of the most common causes of seizures.Cysticercosis is usually acquired by eating food or drinking water contaminated by tapeworms eggs from human feces. Among foods egg-contaminated vegetables are a major source. The tapeworm eggs are present in the feces of a person infected with the adult worms, a condition known as taeniasis. Taeniasis, in the strict sense, is a different disease and is due to eating cysts in poorly cooked pork. People who live with someone with the pork tapeworm have a greater risk of getting cysticercosis. The diagnosis can be made by aspiration of a cyst. Taking pictures of the brain with computer tomography (CT) or magnetic resonance imaging (MRI) are most useful for the diagnosis of disease in the brain. An increased number of a type of white blood cell, called eosinophils, in the cerebral spinal fluid and blood is also an indicator.Infection can be effectively prevented by personal hygiene and sanitation: this includes cooking pork well, proper toilets and sanitary practices, and improved access to clean water. Treating those with taeniasis is important to prevent spread.
Diagnosis
AS is usually diagnosed through visual inspection by an ophthalmologist or optometrist using a slit lamp. Differential diagnoses
Several conditions can have a similar color and appearance. Limbus sign is caused by dystrophic calcification at the corneal limbus, and can be confused with AS in geriatric populations. Anterior embryotoxon is a congenital widening of the corneal limbus. Posterior embryotoxon is a congenital thickening and anterior displacement of schwalbes line.Other conditions with similar appearance, but differing in color are limbal ring, and Kayser–Fleischer ring. Treatment
In the elderly, arcus senilis is a benign condition that does not require treatment. The presence of an arcus senilis in males under the age of 50 may represent a risk factor for cardiovascular disease, and these individuals should be screened for an underlying lipid disorder. The opaque ring in the cornea does not resolve with treatment of a causative disease process, and can create cosmetic concerns. Epidemiology
In men, AS is increasingly found starting at age 40, and is present in nearly 100% of men over the age of 80. For women, onset of AS begins at age 50 and is present in nearly all females by age 90.