Cinchonism
Cinchonism is quinine overdose causing tinnitus, vision loss, and cardiotoxicity.
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, and in much smaller amounts as a bittering agent in tonic drinks. The condition is notable because it can occur from therapeutic doses of quinine, either from one or several large doses, and quinidine (a Class 1A anti-arrhythmic) can also cause cinchonism symptoms to develop with as little as a single dose.
- Mild symptoms
- flushed and sweaty skin, tinnitus, blurred vision, impaired hearing, confusion, reversible high-frequency hearing loss, headache, abdominal pain, rashes, lichenoid photosensitivity, vertigo, dizziness
- Severe symptoms
- skin rashes, deafness, somnolence, diminished visual acuity or blindness, anaphylactic shock, and disturbances in heart rhythm or conduction, and death from cardiotoxicity
Lore & Background
Cinchonism arises from an overdose of quinine or cinchona bark, substances used to treat malaria and lupus erythematosus. The condition can develop from therapeutic doses, either from a single large dose or several large doses. Quinidine, a Class 1A anti-arrhythmic, can also trigger cinchonism symptoms to develop with as little as a single dose. Symptoms range from mild effects like flushed skin, tinnitus, blurred vision, and nausea to severe, reversible outcomes such as deafness, blindness, anaphylactic shock, and disturbances in heart rhythm or conduction, and death from cardiotoxicity.
Reader's Guide
The significance of cinchonism lies in its occurrence even at therapeutic doses of quinine, a drug essential for treating malaria and lupus erythematosus. The article notes that most symptoms are reversible upon withdrawal of quinine, except in severe cases where irreversible tunnel vision and very severe visual impairment have occurred from attempted suicide with a large dose. Additionally, quinine can cause low blood sugar, especially with intravenous administration, and hypotension. The condition is also linked to quinine's mechanism of inactivating lysosomal enzymes, which provides anti-inflammatory effects useful for rheumatoid arthritis but can also lead to toxic myopathy from abnormal accumulation of glycogen and phospholipids. This mechanism is suggested as a possible root cause of cinchonism. The legacy of cinchonism underscores the narrow therapeutic window of quinine and the need for careful dosing, as well as the risk of severe hypersensitivity reactions like blackwater fever in malaria patients.
Did You Know?
- Quinidine, a Class 1A anti-arrhythmic, can cause cinchonism symptoms with as little as a single dose.
- Severe cinchonism can lead to death from cardiotoxicity (damage to the heart).
- Attempted suicide by intake of a large dose of quinine has caused irreversible tunnel vision and very severe visual impairment.
Frequently Asked Questions
What is Cinchonism?
Cinchonism is a toxic reaction triggered by excessive intake of quinine or its natural source, cinchona bark. It can also be provoked by quinidine, a Class 1A anti-arrhythmic drug, even after a single dose.
What are the mild symptoms of Cinchonism?
Early signs include flushed and sweaty skin, ringing in the ears, blurred vision, headache, dizziness, and abdominal discomfort. Some patients also experience reversible high-frequency hearing loss, confusion, or skin rashes.
Can Cinchonism be fatal?
Yes, in severe cases it can lead to permanent deafness, blindness, anaphylactic shock, or dangerous cardiac rhythm disturbances. Death from cardiotoxicity is the most serious terminal outcome.
What medications can trigger Cinchonism?
Quinine itself—used therapeutically for malaria and lupus erythematosus—is the primary culprit, and even standard therapeutic doses can provoke the condition. Quinidine, the anti-arrhythmic derivative, is another well-known trigger, capable of producing cinchonism symptoms after just one administration.
Is Cinchonism reversible?
Mild manifestations such as tinnitus, blurred vision, and high-frequency hearing loss are often reversible once the offending agent is withdrawn. However, severe presentations like permanent deafness, blindness, or cardiac damage may not fully resolve.
More in Poisoning by Drugs, Medicaments and Biological Substances 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced