Confusion and excitability of initially undetermined cause in the course of poisoning with deadly nightshade in attempted suicide: symptoms, differential diagnosis, toxicology and physostigmine treatment of an anticholinergic syndrome

Abstract

History and admission findings: After a walk in a wood a 55-year-old teacher was admitted to the emergency unit of a university hospital because of somnolence and excitability. Her rectal temperature was 37.8 degreesC, she had sinus tachycardia (rate of 130/min)but no other significant findings. Investigations: With the exception of C-reactive protein (10 mg/dl), MCV(101 fl), MCH (34 pg) and arterial blood gases (pH 7.483, pCO(2) 35.5 mmHg, base excess 5.1 mmp/l) laboratory tests were within normal limits. Qualitative screening of serum for benzodiazepines, barbiturates and antidepressives was negative. Neurological examination, including lumbar puncture and cranial computed tomography were noncontributory. Treatment and course: 10 hours after admission the patient developed signs of an anticholinergic syndrome with mydriasis, dry mouth, tachycardia, hot skin and an atonic bladder. Physostigmine 2 mg completely reversed the neurological and mental symptoms. After gas chromatography, mass-spectrometry of a urine sample showed an atropine molecular fragment with a molecular weight of 271. At intervals of 3 to 5 hours the recurrence of confusion and excitability required 4 further i.v. injection of physostigmine. The patient subsequently became accessible to psychiatric examination and reported that during the walk she had swallowed 8-10 berries of deadly nightshade with suicidal intent. Conclusion: In case of excitability and confusion as well as somnolence or coma of uncertain aetiology an anticholinergic syndrome caused by ingestion of atropine-containing plants or psychoactive drugs (phenothiazines, butyrophenones, tri- or tetracyclic antidepressants) should be included in the differential diagnosis. If there are suggestive clinical findings (tachycardia, somnolence, coma or threatened respiratory arrest, physostigmine should be given if there are no contraindications.