Case Presentation
A 19-year-old woman was presented with a generalized tonic clonic seizure followed by severe muscle weakness and muscle ache.
Family History
- The family history was found to be positive for easy fatigability, photosensitivity, hand tremor, myocloni, seizures, ataxia and hypothyroidism.
- The mother experienced an unpleasant feeling in the presence of flickering light and on looking at many stones, leaves or dirty snow on the ground.55
- Both, the mother and the brother of the patient carried the m.8344A > G variant
- The mother had a heteroplasmy rate of 40% and the brother was homoplasmic.
Medical History
- At the age of 7, the patient’s poor school performance due to impaired memory and concentration came to light.
- She experienced nocturnal enuresis up until the age of 14 and menarche at the age of 13 following which she had normal periods.
- At the age of 17, recurrent and spontaneous myocloni of all four limbs began.
Clinical Exam
- The patient experienced recurrent photosensitive focal and generalized seizures.
- EEG revealed epileptiform discharges in the frontocentral regions under hyperventilation and a reduced photoparoxysmal threshold.
- MRI revealed cerebellar atrophy.
- Nerve conduction studies showed a mixed axonal/demyelinating neuropathy.
- The electromyography was found to be myogenic.
Diagnosis
The patient was diagnosed with myoclonic epilepsy with ragged-red fibers (MERRF).
Treatment
- She was administered valproic acid (VPA).
Follow-up
- The patient continued to experience around 1 -2 seizures/month, generalised seizures along with rare incidences of focal seizures.
- Seizures could be triggered by flickering light or by looking at small stones, leaves or dirty snow on the ground.
At the age of 20,
- The VPA was replaced by levetiracetam (LEV) 3000 mg/d.
- Work-up that was carried out for infertility revealed a PCOS for which she received desogestrel (150 μg/d) + estradiol (20 μg/d) twice a year for three months up until the age of 26 years old.
At the age of 21,
- Genetic work-up was performed and it revealed the variant m.8344A > G with a heteroplasmy rate of 50% in blood lymphocytes.
- MRI continued to show cerebellar atrophy.
At the age of 24,
- EEG revealed bilaterally synchronous spike-wave complexes in the occipital area.
- Flickering light triggered generalised, bilaterally synchronous spike-wave and polyspike-wave complexes.
At the age of 27,
- Her ataxic gait worsened and she required another person’s support while walking.
- Elevated serum lactate levels that were double the upper reference limits were observed.
- Topiramate was added to the therapeutic regimen.
At the age of 28,
- A third EEG was consistent with previous findings of cerebellar atrophy.
- No seizures occurred during 42 months period after this
At the age of 32,
- Neurologic examination revealed cognitive impairment, ataxia, photosensitivity, dysarthria, uncoordinated speech, myocloni of upper limbs, generalised wasting, absent tendon reflexes, and gait disturbance.
Clinical Outcome
- Her therapy included LEV (4000 mg/d), clonazepam (CLZ) (1.5 mg/d), TPM (25 mg/d), coenzyme-Q (200 mg/d), L-carnitine (2 g/d), and vitamin-E (400 mg/d).