Sleep disorders with neurological disease: SAQ

Question 1 (10 marks)

Outline your assessment and investigation of the boy with cerebral palsy, the likely diagnosis, and the principles of your management. (10 marks)

Model answer

Likely diagnosis (2 marks). This boy has sleep-disordered breathing, most probably obstructive sleep apnoea with nocturnal hypoventilation, driven by the hypotonic airway collapse of his cerebral palsy and compounded by his oromotor dysfunction, scoliosis, and gastrostomy dependence. His increasing seizure frequency, morning headache, and daytime irritability are the daytime consequences of fragmented and hypoxic sleep, and they illustrate the bidirectional link, because his worsening seizures are both a result of and a contributor to his broken sleep. [7]

Assessment (3 marks). I would take a structured sleep history asking specifically about snoring, witnessed pauses, restless and sweaty sleep, morning mood, and daytime sleepiness, and I would use a validated instrument such as the Sleep Disturbance Scale for Children and a two-week sleep diary. The examination would target the drivers, mapping his oromotor function and tone, his adenotonsillar size, his scoliosis, and his weight and growth, and I would review his medications because sedating antiseizure medicines and baclofen may depress respiratory drive overnight. I would ask the family to film any events. [7] [9]

Investigation (2 marks). The gold-standard test is polysomnography scored by the American Academy of Sleep Medicine rules, which distinguishes obstructive from central events, quantifies the apnoea-hypopnoea index, and assesses for nocturnal hypoventilation with rising carbon dioxide and intermittent desaturation. Overnight pulse oximetry with capnography is a practical screening tool in the community and is particularly useful for monitoring a technology-dependent child over time and after any intervention. [11] [7]

Management (3 marks). Management is stepped and treats the airway and the neurology together. I would optimise his epilepsy and his reflux and constipation in parallel, because uncontrolled nocturnal seizures and reflux will defeat any sleep plan. Definitive treatment may include adenotonsillectomy in a carefully selected child, weighing the postoperative airway risk of a hypotonic child, and continuous positive airway pressure or bilevel non-invasive ventilation for the obstructive and hypoventilating child. He needs lifelong respiratory and sleep monitoring as he grows and after any surgery, and shared care between primary paediatrics, neurodisability, and the sleep service. [7]

Question 2 (10 marks)

Outline your diagnosis and investigation of the girl with daytime sleepiness and emotion-triggered slumping, your management, and the prognosis you would give. (10 marks)

Model answer

Diagnosis (3 marks). This girl has narcolepsy type 1. The combination of irresistible daytime sleep over six months and cataplexy, the sudden emotion-triggered, typically laughter-triggered, bilateral loss of muscle tone with preserved consciousness, is pathognomonic. Cataplexy is the key, because its presence makes narcolepsy type 1, the orexin-deficient form, so likely that it changes the investigation pathway, and I would also ask about hypnagogic hallucinations and sleep paralysis, which complete the tetrad. Narcolepsy type 1 arises from the loss of hypothalamic orexin neurons and is linked to the HLA-DQB1 star 06 colon 02 allele. [1]

Investigation (3 marks). I would arrange an overnight polysomnography to exclude other causes of sleepiness, followed the next morning by a multiple sleep latency test. A mean sleep latency of eight minutes or less with two or more sleep-onset REM periods confirms a central disorder of hypersomnolence, and with cataplexy present this is narcolepsy type 1. Where cataplexy is absent or the picture is ambiguous, cerebrospinal fluid orexin below 110 picograms per millilitre is the definitive biomarker, but in this girl the cataplexy is clear and the lumbar puncture may be avoidable. I would refer urgently to the paediatric sleep service. [1]

Management (3 marks). Management combines non-pharmacological and pharmacological measures. I would prescribe a planned nap schedule and sleep hygiene measures, which reduce daytime sleepiness, and I would coordinate with her school for scheduled nap accommodation. Pharmacotherapy is supervised by the sleep service and may include a wake-promoting agent for the daytime sleepiness and sodium oxybate for the cataplexy. The orexin receptor 2 agonists, established by the Dauvilliers trial, now offer a mechanism-targeted option for narcolepsy type 1 that addresses the missing orexin signal directly. [1] [12]

Prognosis (1 mark). Narcolepsy type 1 is lifelong but highly treatable, and early diagnosis protects her education, her mental health, and her later driving, so I would counsel the family that with a clear plan and school support she can expect to function well, while being honest that the condition will need lifelong management. [1] [12]