Insulinoma misdiagnosed as juvenile myoclonic epilepsy

Abstract

Abbreviations EEG electroencephalography GTCS generalized tonic-clonic seizure JME juvenile myoclonic epilepsy MRI magnetic resonance imagingWe report a girl presenting with drug-refractory myoclonia and generalized tonic-clonic seizure (GTCS) on awakening who, initially, was misdiagnosed as having juvenile myoclonus epilepsy (JME) before insulinoma was detected. Many conditions may mimic or cause epileptic seizures, including psychiatric and movement disorders, cardiac arrhythmias and metabolic abnormalities. Toxic and metabolic causes are potentially curable, are refractory to antiepileptic drugs, and may be fatal if untreated. Insulinoma is a rare and treatable cause of hypoglycemic seizures which might be misdiagnosed as intractable epilepsy. Case reportIn May 2001 a 13-year-old girl was referred to the hospital because of GTCS on awakening. The family history was unremarkable and her personal history revealed one simple febrile seizure at age 3 years. One month before admission two episodes of confusional states were reported which lasted 5 and 30 min and were characterized by unresponsiveness and psychomotor slowing.Physical and neurological examinations were normal, weight was 62 kg (97th centile), height 162 cm (90th centile), and menarche was at age 13 years (March 2001, 1 month before the first seizure). Awake EEG the day after GTCS revealed normal background activity, bilateral synchronous and asynchronous high-amplitude delta waves over the parietotemporal regions, and right frontal sharpslow waves. Blood count, blood chemistry (glucose 4.5 mmol/l, calcium 2.4 mmol/l, potassium 4.0 mmol/l), and magnetic resonance imaging (MRI) of the brain were normal. Confusional states were interpreted as complex partial seizures and GTCS as a secondary generalization. Low-dose carbamazepine (6.3 mg/kg per day) was introduced. Two weeks later, a second GTCS on awakening occurred, followed by two short episodes of unresponsiveness before breakfast in front of the television. Another few days later, perioral and eyelid myoclonus and jerks in the arms and legs were noticed early in the morning. After sleep deprivation a series of myoclonic jerks at awakening in the morning and after several naps were registered coinciding with generalized low-amplitude spikes or polyspikes. JME was diagnosed and carbamazepine replaced by valproate (20 mg/kg per day) which was not effective. Blood glucose was normal (4.2 mmol/l 4 h after food intake). Two months later (August 2001) a second overnight long-term Eur J Pediatr (2007) 166:485-487

Insulinoma masquerading as a loss of consciousness in a teenage girl: case report and literature review

“…Most of the episodes occurred during the morning hours, after exercise or fasting, and resolved after food or juice intake [ 9 , 10 , 14 , 15 , 17 – 19 , 27 ]. Eighteen children experienced seizure activity [ 13 , 14 , 16 , 18 – 21 , 23 – 25 , 27 , 29 , 30 ], four children were found in a comatose state [ 29 , 30 ], three children had mental retardation as sequelae after surgery [ 11 , 27 , 30 ] and two children died [ 22 , 30 ]. Duration of hypoglycemia symptoms before the diagnosis of insulinoma in children ranged from 1 month to 7 years, and averaged 10–13.4 months [ 14 , 17 ].…”

Insulinoma presenting as refractory seizure disorder

“…Of late Wang S. and his colleagues described recurrent episodes of automatism, confusion and convulsion with electroencephalography (EEG) findings resembling the pattern in complex partial seizures in a case of insulinoma 4 . Jaladyan V. and Darbiyan V. described a case of a girl presenting with drug-refractory myoclonia and generalized tonic-clonic seizure (GTCS) initially misdiagnosed as having juvenile myoclonus epilepsy (JME) before insulinoma was detected 5 . O’sullivan S. and Redmond J. also presented a case of insulinoma misdiagnosed as late onset refractory epilepsy 6 .…”

Neuropsychiatric Profiles of Patients with Insulinomas

“…True epileptic discharges are rare even if hypoglycemic convulsions occur. However, Jaladyan and Darbinyan [13] and Graves et al [3] presented cases that were misdiagnosed as epilepsy with epileptiform discharges on EEGs. Slowing in EEG recordings caused by hypoglycemia represents an inhibitory state and adaptive hypometabolism of the brain.…”