Some experts consider that treatment should only be stopped if jaundice becomes clinically evident. If clinically significant hepatitis occurs while on TB treatment, then all the drugs should be stopped until the liver transaminases return to normal. If the patient is so ill that TB treatment cannot be stopped, then STM and EMB should be given until the liver transaminases return to normal (these two drugs are not associated with hepatitis). Fulminant hepatitis can occur in the course of TB treatment, but is fortunately rare; emergency liver transplantation may be necessary and deaths do occur. Test dosing for drug-induced hepatitis
Drugs should be re-introduced individually. This cannot be done in an outpatient setting, and must be done under close observation. A nurse must be present to take patients pulse and blood pressure at 15-minute intervals for a minimum of four hours after each test dose is given (most problems will occur within six hours of test dosing, if they are going to occur at all). Patients can become very suddenly unwell and access to intensive care facilities must be available.
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.