Polysomnographic findings and respiratory management in leigh syndrome – A case report

Introduction Leigh syndrome (LS) is a neurodegenerative disorder with symmetric necrotizing lesions mainly in the basal ganglia, thalamus and brainstem. Respiratory disturbances are a common feature, may have a fluctuating nature and vary from irregular breathing, deep sighing, hyperventilation or hiccups with lethargy to acute respiratory failure. Since this is a rare condition, there are few published descriptions of respiratory symptoms and polysomnographic (PSG) findings. The authors describe clinical and PSG data of a child with LS. Materials and methods Case report with description of the clinical and PSG data of a recently diagnosed LS. The analysis of PSG data was based on the AASM guidelines. Post-sigh apnea (P-S apn) was defined as a pause of chest movements for >= 10 s. preceded by an augmented breath (>= 2x amplitude of the preceding stable respiration). Results A 4 years-old boy was born uneventfully and developed normally until the age of three. He was admitted in a comatous state due to central hypoventilation during an acute respiratory infection. Five months before he had initiated ataxic gait, motor regression, irregular breathing, hiccups and sighs. On examination he had dysmorphic features, hypertrichosis, vertical gaze paralysis, squint, ataxia and tremor. MRI showed bilateral, symmetric focal hyperdensities in basal ganglia and thalamus. Biochemical study identified a complex IV deficiency in mitochondrial respiratory-chain. After respiratory stabilization, non invasive ventilation (NIV) was initiated during sleep. Some days later, he began to refuse it and, as desaturation and hypercapnia had subsided, NIV was suspended. During follow-up he maintained irregular breathing with periods of apneusis-like breathing, frequent sighs and hiccups. PSG was performed six months after diagnosis. Sleep structure was normal with an arousal index of 7.2. Respiratory rhythm was very irregular, with clustered breathing on stage NREM 1/2. There were no obstructive events or isolated central apneas, sighs were very frequent (11/hour) and 40 P-S apn were observed (5/h). Mean SpO2 was 98 % (92–100), TcCO2 40-46 mmHg. During follow-up he maintained frequent sighs and hiccups. The parents were informed that the child should be admitted if irregular breathing with apnea was noticed. Conclusion The PSG findings are consistent with those described in the rare literature for LS. The respiratory management in LS is challenging due to the fluctuation of the respiratory symptoms.