View source for Cinchonism

{{distinguish|Quinism}}
{{Infobox medical condition (new) 
| name            = Cinchonism 
| synonyms        = Quinine toxicity
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'''Cinchonism''' is a [[pathology|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 water|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 [[antiarrhythmic agent|anti-arrhythmic]]) can also cause cinchonism symptoms to develop with as little as a single dose.

==Signs and symptoms==
Signs and [[symptom]]s 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]] ([[Lichen planus|lichenoid]] [[photosensitivity]]),<ref name=pmid7711556>{{cite journal |doi=10.1136/bmj.310.6981.738a |pmid=7711556 |pmc=2549119 |title=Side effect of quinine for nocturnal cramps |journal=BMJ |volume=310 |issue=6981 |pages=738 |year=1995 |last1=Dawson |first1=T A J }}</ref> [[Balance disorder|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 [[cardiac arrhythmia|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]].{{Citation needed|date=September 2008}} Most symptoms of cinchonism (except in severe cases) are reversible and disappear once quinine is withdrawn. Attempted suicide by intake of a large dose of quinine has caused irreversible tunnel vision and very severe visual impairment.<ref name=pmid3281709>{{cite journal |pmid=3281709 |pmc=1041412 |year=1988 |last1=Bacon |first1=P |title=Blindness from quinine toxicity |journal=The British Journal of Ophthalmology |volume=72 |issue=3 |pages=219–24 |last2=Spalton |first2=D. J |last3=Smith |first3=S. E |doi=10.1136/bjo.72.3.219}}</ref>

Patients treated with quinine may also suffer from [[hypoglycemia|low blood sugar]], especially if it is administered [[intravenous]]ly, and [[hypotension]] (low [[blood pressure]]).{{fact|date=December 2017}}

Quinine, like [[chloroquine]], inactivates enzymes in the [[lysosomes]] of cells and has an anti-inflammatory effect, hence its use in the treatment of [[rheumatoid arthritis]]. However, inactivation of these enzymes can also cause abnormal accumulation of glycogen and phospholipids in lysosomes, causing toxic [[myopathy]]. It is possible this action is the root cause of cinchonism.{{fact|date=December 2017}}

== References ==
{{reflist}}

== External links ==
*{{cite journal |first1=Xi |last1=Lin |first2=Shanping |last2=Chen |first3=Daniel |last3=Tee |date=May 1998 |title=Effects of Quinine on the Excitability and Voltage-Dependent Currents of Isolated Spiral Ganglion Neurons in Culture |journal=Journal of Neurophysiology |volume=79 |issue=5 |pages=2503–12 |url=http://jn.physiology.org/content/79/5/2503 |pmid=9582223 |doi=10.1152/jn.1998.79.5.2503|url-access=subscription }}

{{Medical resources
|   DiseasesDB     = 11124 
|   ICD10          = {{ICD10|T|37|2|t|36}} 
|   ICD9           = {{ICD9|386.9}}, {{ICD9|961.4}} 
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{{Diseases of the ear and mastoid process}}
{{Poisoning and toxicity}}

[[Category:Quinine]]
[[Category:Poisoning by drugs, medicaments and biological substances]]