Kayser–Fleischer rings (KF rings) are dark rings that appear to encircle the cornea of the eye. They are due to copper deposition in the Descemets membrane as a result of particular liver diseases. They are named after German ophthalmologists Bernhard Kayser and Bruno Fleischer who first described them in 1902 and 1903. Initially thought to be due to the accumulation of silver, they were first demonstrated to contain copper in 1934. Presentation
The rings, which consist of copper deposits where the cornea meets the sclera, in Descemets membrane, first appear as a crescent at the top of the cornea. Eventually, a second crescent forms below, at the "six oclock position", and ultimately completely encircles the cornea. Associations
Kayser–Fleischer rings are a sign of Wilsons disease, which involves abnormal copper handling by the liver resulting in copper accumulation in the body and is characterised by abnormalities of the basal ganglia of the brain, liver cirrhosis, splenomegaly, involuntary movements, muscle rigidity, psychiatric disturbances, dystonia and dysphagia. The combination of neurological symptoms, a low blood ceruloplasmin level and KF rings is diagnostic of Wilsons disease.Other causes of KF rings are cholestasis (obstruction of the bile ducts), primary biliary cirrhosis and "cryptogenic" cirrhosis (cirrhosis in which no cause can be identified). Diagnosis
As Kayser–Fleischer rings do not cause any symptoms, it is common for them to be identified during investigations for other medical conditions. In certain situations, they are actively sought; in that case, the early stages may be detected by slit lamp examination before they become visible to the naked eye.
Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology
In general, the term "infestation" refers to parasitic diseases caused by animals such as arthropods (i.e. mites, ticks, and lice) and worms, but excluding (except) conditions caused by protozoa, fungi, bacteria, and viruses, which are called infections. External and internal
Infestations can be classified as either external or internal with regards to the parasites location in relation to the host. External or ectoparasitic infestation is a condition in which organisms live primarily on the surface of the host (though porocephaliasis can penetrate viscerally) and includes those involving mites, ticks, head lice and bed bugs.An internal (or endoparasitic) infestation is a condition in which organisms live within the host and includes those involving worms (though swimmers itch stays near the surface). Medically, the term "infestation" is often reserved only for external ectoparasitic infestations while the term infection refers to internal endoparasitic conditions. References
External links
Introduction to Anaerobic Soil Disinfestation as a Fumigant Alternative
New technique predicts risk of plant disease and infestation