EMQ revision - Weakness in the legs

• 60 year old, Female, Bilateral proximal muscle weakness in the legs and dysphagia, Purple rash on cheeks
• Polymyositis
• Non-neurological causes of weakness in legs
• Polymyositis is an autoimmune disease characterised by non-suppurative inflammation of skeletal muscle
• Severe disease involves respiratory muscle weakness and cardiac involvement
• 40 year old, Male, Progressive weakness in arms and legs and episode of diarrhoea, Flaccid weakness of limbs and no reflexes
• Guillain-Barre Syndrome
• Describes a presentation of an ascending polyneuropathy of unknown aetiology, which may be associated with a preceding infection
• Weakness is symmetrical and affects proximal muscles sooner than distal ones
• Cranial nerves and the autonomic nervous system may also be involved
• Involvement of respiratory muscles can be fatal and regular monitoring of vital capcity is important
• In these cases it is often safer to initiate ventilation sooner rather than later
• Sensory symptoms are usually mild with complaints of numbness and tingling in the limbs
• Intravenous immunoglobulin is often used to shorten the duration of the disease
• Prognosis is good with over 85% of patients making a complete or near complete recovery
• 55 year old, Male, Bilateral progressive worsening muscle weakness, Marked wasting of lower limb muscles and very brisk lower limb reflexes, Sensation normal
• Motor Neuron Disease (MND)
• Progressive degenerative disease that affects the upper and lower motor neurons
• NO sensory involvement characteristically
• Pattern
• Progressive muscular atrophy
• Anterior horn wasting lesion with wasting often beginning in the distal muscles of the hand and then spreading. Fasciculation is a common finding
• Amyotrophic lateral sclerosis
• Involvement of the lateral corticospinal tract gives a progressive spastic teraparesis/paraparesis
• The presence of LMN signs, e.g. wasting, fasciculation differentiates this diagnosis from other causes of spastic weakness
• Progressive bulbar palsy
• The lower cranial nerve nuclei and their connections are primarily affected
• Dysarthria and dysphagia are common symptoms
• This pattern of disease is more common in women than in men
• 13 year old, Male, Bilateral pes cavus, Clawing of the toes, There is atrophy of peroneal muscles, Reduced reflexes and sensation distally
• Charcot-Marie-Tooth disease
• Progressive peroneal muscle atrophy
• Autosomal dominant or recessive
• Now described as a hereditary sensorimotor neuropathy (HSMN) because several clinical variants have been identified associated with different gene defects
• HSMN types I and II are the most common types
• HSMN type I is a demyelinating neuropathy of insidious onset presenting typically in the first decade of life with foot deformities (e.g. pes cavus), muscle weakness (distal weakness that affects legs earlier and more severely than arms) and loss of balance. The presence of foot drop results in frequent trips and falls
• HSMN type II usually presents later in the second decade of life. The weakness in distal lower limb muscles is often accompanied by distal sensory loss. Foot deformities are less marked than in type I disease and patients may even be completely asymptomatic
• 30 year old, Bilateral leg weakness, Blurred vision, Fundoscopy reveals pale optic discs bilaterally
• Multiple Sclerosis
• In this case the pale bilateral optic discs indicate previous subclinical episodes of optic neuritis
• Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) that has a progressive course
• There is an increased prevalence further away from the equator but the aetiology is still unknown
• More women are affected
• Diagnosis is made clinically but magnetic resonance imaging (MRI) is the imaging of choice to detect demyelinating plaques
• CSF examination usually shows oligoclonal bands of IgG on electrophoresis
• Electrophysiological tests reveal delays in the propagation of potentials (e.g. visual, somatosensory, auditory evoked potentials)
• Intravenous methylprednisolone can reduce the severity of relapses but does not improve long-term prognosis
• Interferon-beta has been shown to reduce the relapse rate in patients suffering from relapsing-remitting form of the illness but its use is limited because of its high cost