Narcolepsy is a rare condition characterised by excessive daytime sleepiness, sleep paralysis, hypnagogic hallucinations, and cataplexy (sudden collapse triggered by emotion such as laughing or crying). There is no cure for narcolepsy. Treatment options include stimulants, such as methylphenidate (Ritalin) or modafinil (Provigil), antidepressants, such as fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft) and sodium oxybate (Xyrem). Modafinil has replaced methylphenidate and amphetamine as the first-line treatment of excessive daytime sleepiness (EDS).

Because of the patient’s history of chronic analgesic use of daily paracetamol intake, the most likely diagnosis of this case is Analgesic misuse headache. In these cases, the headache is only temporarily relieved by analgesics. Treatment involves gradual withdrawal of analgesics.

Guillain-Barre syndrome is an immune mediated demyelination of the peripheral nervous system often triggered by an infection (classically Campylobacter jejuni). Characteristic features include progressive weakness of all four limbs, and it is classically ascending, affecting the lower extremities first. Sensory symptoms tend to be mild.

Functional neurological syndrome can be discounted due to presence of hard neurological signs. Multiple sclerosis can be excluded because of the presence of lower motor neuron signs and absence of upper motor neuron signs. Chronic inflammatory demyelinating polyneuropathy is the chronic form of Guillain-Barre syndrome.

Myotonic dystrophy is the most likely diagnosis here.
It is a multisystem disorder causing cognitive impairment, cataracts, cardiac problems and testicular atrophy, as well as affecting the muscles. Patients have muscle weakness, normally worse distally, and/or myotonia (which is worse in cold weather).
On examination, patients may also have frontal balding, a myopathic facies, bilateral ptosis, an ophthalmoplegia and wasting of facial muscles and other limb muscles. Myotonic dystrophy is associated with diabetes mellitus and pituitary dysfunction.
Diagnosis is normally based on clinical features with a characteristic electromyogram (EMG) of myotonic discharges. Creatine kinase is generally normal and muscle biopsy is non-specific.

Bilateral median nerve dysfunction is suggestive of degenerative cervical myelopathy (DCM) rather than bilateral carpal tunnel syndrome. DCM should be suspected in elderly patients presenting with limb neurology. This patient’s twitches are probably fibrillations, a sign of lower motor neuron dysfunction.
Degenerative cervical myelopathy is associated with a delay in diagnosis. It is most commonly misdiagnosed as carpal tunnel syndrome. In one study, 43% of patients who underwent surgery for degenerative cervical myelopathy had been initially diagnosed with carpal tunnel syndrome.
Management of these patients should be by specialist spinal services (neurosurgery or orthopaedic spinal surgery). Decompressive surgery is the mainstay of treatment and has been shown to stop disease progression. Physiotherapy and analgesia do not replace surgical opinion, though they may be used alongside. Nerve root injections do not have a role in management.

Retinal and cerebellar haemangiomas are key features of Von Hippel-Lindau syndrome. Retinal haemangiomas are bilateral in 25% of patients and may lead to vitreous haemorrhage. Von Hippel-Lindau (VHL) syndrome is an autosomal dominant condition predisposing to neoplasia. It is due to an abnormality in the VHL gene located on short arm of chromosome 3.

Motor neuron disease is a neurological condition of unknown cause which can present with both upper and lower motor neuron signs. It rarely presents before 40 years and various patterns of disease are recognised including amyotrophic lateral sclerosis, primary lateral sclerosis, progressive muscular atrophy and progressive bulbar palsy. In some patients however, there is a combination of clinical patterns. In progressive bulbar palsy there is palsy of the tongue and muscles of chewing/swallowing and facial muscles due to loss of function of brainstem motor nuclei. This carries the worst prognosis.

Gilles de la Tourette syndrome is the most severe and rare of the tic syndromes, consisting of multiple tics involving both motor actions and vocalisation. Onset is usually in childhood. Symptoms include utterance of obscenities (coprolalia); echolalia (repetition of another person’s spoken words) and palilalia (involuntary repetition of words, phrases, or sentences).
The underlying cause is unknown, with no particular imaging or standard histopathological abnormalities having been identified. The EEG shows non-specific abnormalities in about half of patients. However, more recent immunocytochemical studies have suggested altered dopamine uptake in the striatal system.
Risperidone is an effective therapeutic option without the effects associated with chlorpromazine and haloperidol.

Friedreich’s ataxia is an autosomal recessive disorder that usually begins before the end of the teens. It has an estimated prevalence in Europe of 1 in 50,000 and life expectancy is around 40–50 years. Neurological features include a progressive ataxia, cerebellar dysarthria, lower limb areflexia, decreased vibratory sensation and proprioception, and pyramidal weakness. Pes cavus and scoliosis are also both seen. Cardiomyopathy occurs in over 70% of cases. Less common features include optic atrophic, diabetes mellitus, and deafness.

Entrapment of the median nerve by pronator teres causes a median nerve neuropathy, which is worse during pronation of the forearm. Examination should involve excluding carpal tunnel syndrome and pronation of the affected forearm against resistance, which brings on the pain. Unlike carpal tunnel syndrome, the median nerve proximal to the wrist may be tender to palpation.