The sciatic neve originates in the sacral plexus, mainly from spinal segments L5-S2. It supplies muscles that cause extension of the thigh and flexion of the leg. It divides into two main branches, the tibial nerve and common peroneal nerve, which are responsible for all foot movements. Anterior thigh and medial leg sensory loss is typical of a femoral nerve lesion. The femoral nerve also mediates flexion of the hip.

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.

The given history suggests a small fibre painful peripheral sensory neuropathy, the most common cause of which is diabetes. Joint position sense and vibratory sensation are carried through large fibres, and therefore are not currently affected. Sensory nerves are affected more often than motor, so reflexes usually remain in tact.

Vitamin B12 deficiency causes impairment of joint position and vibratory sensation.

Chronic inflammatory demyelinating polyneuropathy (CIPD) causes a large fibre peripheral neuropathy with areflexia.

In syringomyelia there is impaired pain and temperature noted in the upper limbs.

Finally, with alcoholic polyneuropathy, all fibre types are affected (sensory and motor loss). It is usually gradual with long term alcohol abuse and may be accompanied by a nutritional deficiency. In addition, pain is a more dominant feature.

A lesion on the cavernous sinus would explain the palsy observed on the III and VI cranial nerves because the cranial nerves III, IV, V, and VI pass through the cavernous sinus. Pain in the eye is due to the nearby ophthalmic veins that feeds the cavernous sinus. Additionally, the lesions in the other structures would have presented with pupil abnormalities and less localized pain and symptoms.

The history is consistent with carpal tunnel syndrome (CTS) arising as a result of pressure on the median nerve in the carpal tunnel. The median nerve supplies the muscles of the thenar eminence: the abductor pollicis (C7, C8), flexor pollicis brevis and opponens pollicis, and the lateral two lumbricals. The nerve conduction studies confirm marked denervation and absent sensory potentials within the median nerve territory.

The pons is above the level of decussation of the corticospinal tracts so a pontine lesion would cause a contralateral limb weakness.
The facial motor nucleus is located in the pons and supplies the ipsilateral facial muscles.
A right cerebral lesion would give left upper and lower limb weakness. It would also cause a left sided facial weakness.
A left cerebral lesion would give right upper and lower limb weakness with right facial weakness.
Finally, a cervical spinal cord lesion would not cause a facial weakness.

The differential diagnosis of bilateral exercise-induced pain would include metabolic muscle disease, lumbar canal stenosis and intermittent claudication. The patient’s age, history and lack of other risk factors make the latter two options unlikely.

The syndrome described is in fact McArdle’s disease (myophosphorylase deficiency). This is a disorder of carbohydrate metabolism. Clinical features of pain and fatigue are precipitated in early exercise, as carbohydrates cannot be mobilized to provide an energy substrate to the muscle. With prolonged exercise, fatty acid metabolism provides energy, and symptoms lessen. The dark urine described is likely to represent myoglobinuria following rhabdomyolysis. Definitive diagnosis of most metabolic muscle diseases relies on muscle biopsy and enzyme analysis.

Weber’s test – if there is a sensorineural problem, the sound is localized to the unaffected side (right), indicating a problem on the left side.

West Nile virus (WNV) is a single-stranded RNA flavivirus transmitted via the culex mosquito. This previously ‘tropical’ disease has became topical in recent years following a large scale outbreak in the New York area. Incidence of neurological involvement is around 1%, although some suggest that the incidence of meningoencephalitis in America is higher than in other parts of the world. Risk factors for neurological involvement include increasing age, and immunosuppression. The usual picture is of sudden onset fever and myalgia with nausea and vomiting and a non-specific rash. Transient meningitis is occasionally seen. Frank meningoencephalitis is seen in two-thirds of cases with neurological involvement; 15% progress to coma. A flaccid paralysis similar to acute Guillain–Barré is increasingly recognised.
Diagnosis is initially clinical with subsequent serological confirmation. Treatment is supportive; results from trials of antivirals have yielded disappointing results.

The patient is presenting with symptoms of lateral medullary syndrome also known as Wallenberg’s syndrome or posterior inferior cerebellar artery syndrome, where the symptoms are due to an ischemia in the brainstem. The classical symptoms include contralateral sensory deficits of the trunk region paired with ipsilateral facial sensory deficits.

Huntington’s disease is an autosomal inherited condition characterized by progressive dementia and worsening choreiform movements. Symptoms typically appear between ages 30 and 50. Ultimately the weakened individual succumbs to pneumonia, heart failure, or other complications.

The patient’s history and presentation and familial history, meets the diagnostic criteria for Neurofibromatosis type I, presenting with neurofibromas noted in this patient as hyperpigmented macules and freckles, musculoskeletal disorders like the scoliosis in this case, and a familial history. Neurofibromatosis type I is caused by a mutation on Chromosome 17.

This man has a small-cell lung cancer (SCLC) and associated Lambert-Eaton myasthenic syndrome – a well-recognized paraneoplastic manifestation of SCLC. This classically affects the proximal muscles, especially in the legs, causing difficulty in standing from a seated position and climbing stairs. In contrast to myasthenia gravis, eye involvement is uncommon. Treatment with steroids is often helpful, which explains his transient symptomatic improvement during treatment for his COPD exacerbation. Steroid myopathy does not fit as the symptoms started well before his course of prednisolone. Although the patient is mildly hypercalcaemic, this would not be sufficient to produce his presenting symptoms, although it does reinforce the suspicion of lung malignancy. Motor neurone disease would be unlikely in this context and would not improve with steroids. Myasthenia gravis could produce these symptoms, but in the context of a new lung mass is a less viable diagnosis.

A history of ischaemic heart disease in a contraindication for prescribing triptans because they act by constricting cerebral and also coronary vessels, increasing the risk of stroke.

The case presents with an underlying ovarian tumour, associated with psychiatric symptoms; thus, an organic illness must first be ruled out before considering the other conditions listed which often present with psychiatric features without an underlying organic disease. Among the listed conditions Anti-NMDA receptor encephalitis is the only condition that presents with psychiatric features including agitation, hallucinations, delusions and disordered thinking that is associated with tumours 50% of the time.

Oculomotor nerve palsy is an eye condition resulting from damage to the third cranial nerve or a branch thereof. A complete oculomotor nerve palsy will result in a characteristic down and out position in the affected eye. This is because the lateral rectus (innervated by the sixth cranial nerve) and superior oblique (innervated by the fourth cranial or trochlear nerve), is unantagonized by the paralyzed superior rectus, inferior rectus and inferior oblique. The affected individual will also have a ptosis, or drooping of the eyelid, and mydriasis (pupil dilation), not miosis.

A lucid interval, in which the patient portrays a temporary improvement in condition after a traumatic brain injury, is especially indicative of an epidural haematoma.

Baclofen is used to treat spastic movement symptoms such as those seen in cerebral palsy and multiple sclerosis. It is known to be associated with a withdrawal syndrome similar to alcohol withdrawal; thus, gradual withdrawal is necessary to avoid this.

The pattern of muscle involvement seen with quadriceps and long-finger flexors is characteristic of inclusion body myositis, an inflammatory myopathy. Polymyositis is likely to cause a predominantly proximal weakness, associated with muscle pain. The signs and symptoms are not consistent with upper cord compression, as there would likely be sensory signs, reflex changes, and possible urinary symptoms. Motor neuron disease cannot be ruled out, but there are no findings of upper motor neuron or bulbar features.

This patient is having a myasthenic crisis. Opinions vary as to whether plasmapheresis or intravenous immunoglobulins should be given first-line. Plasmapheresis usually works much faster, but is more costly due to equipment.
Myasthenia gravis is an autoimmune disorder resulting in insufficient functioning acetylcholine receptors. Antibodies to acetylcholine receptors are seen in 85-90% of cases. Myasthenia gravis is more common in women (2:1).