Sir,

Quinine is widely used to treat leg cramps in the elderly.1 Its use has long been associated with thrombocytopenia.2 We report a case of quinine-induced thrombocytopenia manifesting with a suprachoroidal haemorrhage during cataract surgery.

Case report

A 75-year-old man underwent left cataract surgery. Visual acuity was 6/12 in both eyes. He took quinine sulphate 300 mg OD for leg cramps. His past medical and drug history was otherwise unremarkable. Peribulbar anaesthesia was given uneventfully. During phacoemulsification and removal of the final quadrant of the lens nucleus, the eye became tense, the red reflex reduced, and an anterior capsule tear extended posteriorly causing vitreous loss. Intravenous acetazolamide (500 mg) was given immediately, an anterior vitrectomy completed, a sulcus intraocular lens inserted, and the wound sutured.

The following day, the visual acuity was hand movements. Fundus and ultrasound examination (Figure 1a) confirmed extensive suprachoroidal haemorrhage. A full blood count (FBC) showed thrombocytopenia (platelet count 87 × 109/l). Haematology opinion was sought; investigations including a blood film and autoimmune screen were normal. Quinine was stopped and the platelet count has gradually risen. With conservative management, the left visual acuity has improved to 6/6 at 4 months post-surgery despite the presence of macular choroidal folds (Figures 1b and c).

Figure 1
figure 1

(a) B-scan ultrasonography of the left eye 1 day after surgery showing suprachoroidal haemorrhage. Colour fundus photographs of the left eye 4 months after surgery showing (b) residual choroidal macular folds and (c) peripheral pigmentary retinopathy following reabsorption of haemorrhage.

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Comment

Expulsive suprachoroidal haemorrhage is a rare but potentially devastating event during intraocular surgery. Occult thrombocytopenia is the only identifiable risk factor for haemorrhage in this patient. Extensive haematological investigation has strongly suggested quinine drug-induced immune thrombocytopenia (DITP). The rise in platelet count since cessation of quinine supports this.

Quinine causes DITP by stimulating production of antibodies against platelet membrane glycoproteins causing platelet destruction. Treatment includes drug withdrawal and control of bleeding.2 We believe this is the first reported case of quinine-induced thrombocytopenia associated with intraocular haemorrhage.

Awareness of quinine use in the elderly population is important. The Royal College of Ophthalmologists local anaesthetic guidelines suggest a pre-operative FBC only for patients with a history of systemic disease or abnormal examination.3 We feel that occult thrombocytopenia significantly contributed to the suprachoroidal haemorrhage in this case and recommend an FBC prior to intraocular surgery for all patients taking quinine.