Ocular quinine toxicity followed by electroretinogram, electro-oculogram, and pattern visually evoked potential

Area of Science:

• Ophthalmology
• Neuroscience
• Toxicology

Background:

• Quinine, an antimalarial and antiarrhythmic drug, is known for its potential ocular toxicity in overdose scenarios.
• Understanding the temporal effects of quinine toxicity on retinal function is crucial for diagnosis and management.

Observation:

• A single patient ingesting quinine for a suicide attempt was monitored using electrophysiological methods over six months.
• Serial electroretinograms (ERG), electrooculograms (EOG), and pattern visually evoked potentials (PVEP) were performed.

Findings:

• The electroretinogram showed early abnormalities including increased a-wave and decreased b-wave amplitudes, prolonged implicit times, and reduced oscillatory potentials.
• The electrooculogram demonstrated a diminished 'light rise,' and pattern visually evoked potentials exhibited increased implicit times throughout the study period.

Implications:

• These findings suggest a direct and early toxic impact of quinine on retinal cellular function.
• Electrophysiological testing can reveal subtle, progressive retinal dysfunction following quinine ingestion.
• This case highlights the importance of considering quinine toxicity in patients presenting with visual disturbances and a history of overdose.