Cavina-Pratesi C, Kentridge RW, Heywood CA, Milner AD (February 2010). "Separate processing of texture and form in the ventral stream: evidence from FMRI and visual agnosia". Cereb. Cortex. 20 (2): 433–46. doi:10.1093/cercor/bhp111. PMID 19478035. Goodale MA; Milner AD (2004). Sight Unseen: An Exploration of Conscious and Unconscious Vision. Oxford UK: Oxford University Press. pp. 139. ISBN 978-0-19-856807-0. OCLC 54408420. Farah M (2004). Visual Agnosia. 2nd Edition. Cambridge MA: MIT Press: Bradford Books. p. 192. ISBN 978-0-262-56203-4. OCLC 57182718.
Cinchonism is a pathological condition caused by an overdose of quinine or its natural source, cinchona bark. Quinine and its derivatives are used medically to treat malaria and lupus erythematosus. In much smaller amounts, quinine is an ingredient of tonic drinks, acting as a bittering agent. Cinchonism can occur from therapeutic doses of quinine, either from one or several large doses. Quinidine (a Class 1A anti-arrhythmic) can also cause cinchonism symptoms to develop with as little as a single dose. Signs and symptoms
Signs and symptoms of mild cinchonism (which may occur from standard therapeutic doses of quinine) include flushed and sweaty skin, ringing of the ears (tinnitus), blurred vision, impaired hearing, confusion, reversible high-frequency hearing loss, headache, abdominal pain, rashes, drug-induced lichenoid reaction (lichenoid photosensitivity), vertigo, dizziness, nausea, vomiting and diarrhea. Large doses of quinine may lead to severe (but reversible) symptoms of cinchonism: skin rashes, deafness, somnolence, diminished visual acuity or blindness, anaphylactic shock, and disturbances in heart rhythm or conduction, and death from cardiotoxicity (damage to the heart). Quinine may also trigger a rare form of hypersensitivity reaction in malaria patients, termed blackwater fever, that results in massive hemolysis, hemoglobinemia, hemoglobinuria, and kidney failure. Most symptoms of cinchonism (except in severe cases) are reversible and disappear once quinine is withdrawn.