MEERWALDT (University Hospital "Dijkzigt," 3015 GD Rotterdam, The Netherlands) write: Digoxin is a widely prescribed drug with narrow therapeutic margins, and intoxication is a common complication. We report a case ofsevere generalised chorea, agitation, and emotional disturbance due to digoxin excess.A 63 year old woman with a dissection of the ascending aorta had been treated conservatively for one month with digoxin 250 ig daily, labetalol 100 mg three times a day, dihydralazine 25 mg twice a day, isosorbide mononitrate 20 mg three times a day, bromazepam 1 5 mg three times a day, and triamterene one capsule daily. During the operation the defect of the intima was reconstructed with a haemoshield prosthesis (anaesthetic: fentanyl 36 ml and pancuronium 18 mg). The patient was haemodynamically stable immediately afterwards. Postoperatively she was treated with digoxin 250 [tg daily, triamterene one capsule daily, and, for three days, prednisolone acetate 25 mg daily. Three days after the operation she started to complain of extreme fatigue, showed no clouding of consciousness but was disoriented in time, appeared to be frightened, and had an impaired memory. Generalised symmetric choreatic movements increased in severity during the next few days to such an extent that she injured herself. The patient had neither been treated with neuroleptic drugs nor received other medication in the past which could have caused chorea. There was no history ofrheumatic fever. Computed tomography of the brain without contrast enhancement showed no abnormalities. Extensive laboratory values were repeatedly within normal ranges, except for urea and creatinine, which were temporarily raised, consistent with transient renal failure. The digoxin value, which had not been recorded previously, was 34 tg/l (therapeutic range 10-26 ,tg/l) one week after surgery. Digoxin was then discontinued and she was treated successfully with oral haloperidol 5 mg daily for one month. After the tapering off of haloperidol the abnormal involuntary movements did not return (follow up two years).There are only limited data on the relation between non-cardiac symptoms of digoxin toxicity and serum digitalis concentrations. ' Above 30 Fg/l (in our patient 34 [tg/l) there is a high incidence of intoxication, especially with renal failure.2 In contrast to a previously reported patient, who had hemichorea due to digoxin toxicity,3 our patient had generalised symmetric chorea. After the withdrawal of digoxin haloperidol was discontinued and the choreatic movements did not return. The fact that haloperidol controlled the choreatic movements might suggest that digoxin toxicity induces a functional alteration in the activity of dopamine at the synaptic level.4 The involvement of dopaminergic pathways might also explain the psychotic symptoms of digoxin intoxication, as in the more common organic brain syndromes.56 Digoxin toxicity should be included in the differential diagnosis of iatrogenic choreatic disorders.
