Neurology: Cerebral Palsy; Hydrocephalus; BMD; DMD Flashcards
Define cerebral palsy [1]
Cerebral palsy (CP) is the name given to the permanent neurological problems resulting from damage to the brain around the time of birth.
- It is not a progressive condition, however the nature of the symptoms and problems may change over time during growth and development.
What are the different classifications of cerebral palsy? [4]
Describe their features [4]
Where do each of the above have damage that causes them? [4]
Classification
Spastic:
- hypertonia (increased tone) and reduced function resulting from damage to upper motor neurones
Dyskinetic:
- problems controlling muscle tone, with hypertonia and hypotonia, causing athetoid movements and oro-motor problems.
- This is the result of damage to the basal ganglia.
Ataxic:
- problems with coordinated movement resulting from damage to the cerebellum
Mixed:
- a mix of spastic, dyskinetic and/or ataxic features
Children who suffer which condition are at high risk of CP? [1]
. Children at risk of developing cerebral palsy, such as those with hypoxic-ischaemic encephalopathy, need to be followed up to identify any signs and symptoms that develop.
Signs and symptoms of cerebral palsy will become more evident during development.
What are they? [6]
Failure to meet milestones
Increased or decreased tone, generally or in specific limbs
Hand preference below 18 months is a key sign to remember for exams
Problems with coordination, speech or walking
Feeding or swallowing problems
Learning difficulties
You can gain a lot of information about a child from their gait:
Hemiplegic / diplegic gait: indicates an [] lesion
Broad based gait / ataxic gait: indicates a [] lesion
High stepping gait: indicates foot drop or a [] lesion
Waddling gait: indicates pelvic muscle weakness due to []
Antalgic gait (limp): indicates localised []
Hemiplegic / diplegic gait: indicates an upper motor neurone lesion
Broad based gait / ataxic gait: indicates a cerebellar lesion
High stepping gait: indicates foot drop or a lower motor neurone lesion
Waddling gait: indicates pelvic muscle weakness due to myopathy
Antalgic gait (limp): indicates localised pain
TOM TIP: Get used to assessing and recognising the patterns of upper and lower motor neurone lesions. Cerebral palsy is a perfect condition for examiners to bring to OSCEs, because signs are reliable and patients are stable. The differential diagnosis of an upper motor neurone lesion is acquired brain injury or a tumour.
Patients with cerebral palsy may have a hemiplegic or diplegic gait. This gait is caused by [2] in the legs.
Patients with cerebral palsy may have a hemiplegic or diplegic gait. This gait is caused by increased muscle tone and spasticity in the legs.
Mx for CP:
Paediatricians will regularly see the child to optimise their medications. This may involve: [3]
Muscle relaxants (e.g. baclofen) for muscle spasticity and contractures
Anti-epileptic drugs for seizures
Glycopyrronium bromide for excessive drooling
What are the four ventricles in the brain? [4]
- What are their roles? [1]
- Where is CSF exactly made? [1]
- Where is CSF absorbed? [1]
There are four ventricles in the brain: two lateral ventricles, the third and the fourth ventricles.
- The ventricles containing CSF.
- The CSF provides a cushion for the brain tissue
- CSF is created in the four choroid plexuses (one in each ventricle) and by the walls of the ventricles.
- CSF is absorbed into the venous system by the arachnoid granulations.
What are the congenital causes of hydrocephalus? [1]
Describet the basic pathophysiology [1]
The most common cause of hydrocephalus is aqueductal stenosis, leading to insufficiency drainage of CSF.
- The cerebral aqueduct that connects the third and fourth ventricle is stenosed (narrowed).
- This blocks the normal flow of CSF out of the third ventricle, causing CSF to build up in the lateral and third ventricles.
Describe the presentation of hydrocephalus in children [5]
The cranial bones in babies are not fused at the sutures until around 2 years of age. Therefore, the skull is able to expand to fit the cranial contents.
- When a baby has hydrocephalus it causes outward pressure on the cranial bones. Therefore, babies with hydrocephalus will have an enlarged and rapidly increasing head circumference (occipito-frontal circumference). Also:
- Bulging anterior fontanelle
- Poor feeding and vomiting
- Poor tone
- Sleepiness
How do you treat a hydrocephalus? [1]
Placing a VP shunt that drains CSF from the ventricles into another body cavity is the mainstay of treatment for hydrocephalus.
- Usually the peritoneal cavity is used to drain CSF, as there is plenty of space and it is easily reabsorbed.
- The surgeon places a small tube (catheter) through a small hole in the skull at the back of the head and into one of the ventricles.
- A valve on the end of this tube is placed subcutaneously, and a catheter on the other side of the valve runs under the skin into the peritoneal cavity. The valve helps to regulate the amount of CSF that drains from the ventricles.
What is a key risk of VP shunt placement? [1]
Intraventricular haemorrhage during shunt related surgery
What is the pathophysiology of DMD and BMD? [2]
Becker muscular dystrophy (BMD):
- X-linked recessive disorder resulting from mutations in the DMD gene, which encodes for the protein dystrophin used in muscle fibre stability.
- non-frameshift insertion in the dystrophin gene resulting in both binding sites being preserved leading to a milder form
Duchenne muscular dystrophy:
- Due to mutation in the gene encoding dystrophin
- frameshift mutation resulting in one or both of the binding sites are lost leading to a severe form
Describe the clinical features of DMD [5]
Clinical features
* Proximal muscle weakness, of a proximal to distal pattern, typically develops from 2-3 years of age
* Motor milestones may be delayed
* Gait abnormalities (e.g. waddling gait) and frequent falls are common
* Calf pseudohypertrophy
* Gower’s sign: child uses arms to stand up from a squatted position
* 30% of patients have intellectual impairment
Describe the motor features of BMD [5]
Motor Symptoms
* Gower’s sign: child uses arms to stand up from a squatted position
* Waddling gait: As the disease progresses, patients may develop a waddling gait, caused by weakness in the pelvic muscles.
* Muscle cramps: These can occur after exercise and are sometimes the initial symptom of BMD.
* Muscle hypertrophy: Enlargement of calf muscles is commonly observed. However, this hypertrophy is often pseudohypertrophy where increased fat and connective tissue replace muscle fibres.
Describe the cardiac [1], pulmonary [2] and cognitive features [2] of BMD
Cardiac Manifestations
* BMD frequently involves cardiac muscle leading to dilated cardiomyopathy.
* Patients may present with symptoms of heart failure such as dyspnoea, fatigue or fluid retention. Cardiac arrhythmias are also common.
Pulmonary Manifestations
* In later stages of BMD, patients may develop respiratory muscle weakness leading to impaired pulmonary function. Symptoms can include dyspnoea on exertion and recurrent respiratory infections.
Cognitive and Behavioural Features
* Though not as common, cognitive impairment and behavioural issues can be associated with BMD. These can include learning difficulties and attention deficit disorder.
How do you investigate for BMD and DMD? [2]
First-line Investigations
* Creatine Kinase (CK) blood test: This is an initial screening tool for muscle damage. In BMD, CK levels are typically elevated due to ongoing muscle breakdown.
* Molecular genetic testing: This forms the cornerstone of BMD diagnosis. The identification of a mutation in the dystrophin gene confirms the diagnosis.
Which further tests might you conduct for BMD? [3]
Further Investigations
Muscle biopsy:
- A muscle biopsy can help confirm the diagnosis when genetic testing does not identify any pathogenic variant. Immunohistochemistry or immunoblotting can demonstrate reduced dystrophin protein expression.
Echocardiogram:
- Given that cardiac involvement is common in BMD, regular echocardiography should be part of routine monitoring. It allows assessment of left ventricular function and early detection of cardiomyopathy.
Pulmonary function tests:
- These tests are crucial in assessing respiratory muscle strength and lung capacity, as respiratory failure is a common cause of morbidity and mortality in advanced stages of BMD.
Describe the mx of BMD [1]
Corticosteroids:
- Prednisolone or Deflazacort are the first-line therapy to delay muscle weakness. Monitor for side effects including weight gain, osteoporosis and behavioural changes.
Desribe the managment of BMD that would help with cardiac and pulmonary mx and other support that might be given [3]
Cardiac Management:
- Regular cardiac assessments should be conducted due to the high risk of cardiomyopathy.
- Angiotensin-converting enzyme inhibitors or beta-blockers may be used as prophylaxis against left ventricular dysfunction.
- Consideration should also be given to implantable cardioverter-defibrillators or cardiac resynchronisation therapy in patients with severe cardiac involvement.
Pulmonary Management:
- Pulmonary function tests should be conducted annually.
- Non-invasive ventilation may be necessary in later stages of the disease to manage hypoventilation during sleep.
Mobility and Physical Therapy:
- Physiotherapy is essential to maintain mobility and prevent contractures.
- Orthotic devices may provide additional support.
Nutritional Support:
- A dietitian should assess nutritional needs regularly due to the risk of dysphagia and weight loss. Gastrostomy feeding may become necessary in advanced stages.
Surgical Interventions:
- Spinal surgery may be required for progressive scoliosis while orthopaedic surgery can help manage contractures and fractures resulting from osteoporosis.
Myotonic dystrophy is a genetic disorder that usually presents in adulthood. Typical features are [4]
Progressive muscle weakness
Prolonged muscle contractions
Cataracts
Cardiac arrhythmias
TOM TIP: The key feature of myotonic dystrophy to remember is the prolonged muscle contraction. This may present in exams with a patient that is unable to let go after shaking someones hand, or unable to release their grip on a doorknob after opening a door. When doing an upper limb neurological examination always shake the patients hand and observe for difficulty releasing their grip.
Describe the muscular manifestations of myotonic dystrophy [3+]
Myotonia
* The hallmark feature of DM is delayed muscle relaxation following voluntary contraction or percussion, termed myotonia.
* Myotonia can be generalized or focal, affecting the hands, tongue, facial muscles, or lower limbs.
Muscle Weakness
* Both DM1 and DM2 present with progressive muscular weakness; however, the distribution and severity may vary between subtypes.
* Distal Limb Weakness (DM1): In DM1 patients, distal limb weakness predominantly affects the flexor muscles of the fingers, wrists, and ankles. In advanced stages, proximal limb muscles may also be involved.
* Proximal Limb Weakness (DM2): Patients with DM2 typically exhibit proximal limb weakness affecting hip girdle muscles more than shoulder girdle muscles. The weakness pattern in DM2 often resembles that of limb-girdle muscular dystrophy.
Facial & Bulbar Weakness
* Facial muscle involvement in both subtypes may manifest as ptosis, facial diplegia, dysarthria, dysphagia or nasal regurgitation due to palatal insufficiency.
Describe the cardiac [4], respiratory [2] and endocrine [3] manifestations of muscular dystrophy
Systemic Manifestations
Cardiac Involvement
* Cardiac abnormalities are common in DM patients and may include arrhythmias such as atrioventricular block or atrial fibrillation, dilated cardiomyopathy, and sudden cardiac death.
Respiratory Involvement
* Respiratory insufficiency due to diaphragmatic or intercostal muscle weakness is a significant concern in DM patients.
* Sleep-disordered breathing, including sleep apnea and hypoventilation syndromes, may also occur.
Endocrine & Metabolic Abnormalities
* DM patients may exhibit insulin resistance or type 2 diabetes mellitus, hypogonadism with testicular atrophy (DM1), primary ovarian failure (DM2)
The treatment of MD is a MDT approach.
In terms of pharmacotherapy, [] can be used for myotonia, but its use should be guided by a neurologist. Steroids are not recommended due to potential worsening of myotonia.
In terms of pharmacotherapy, Mexiletine can be used for myotonia, but its use should be guided by a neurologist. Steroids are not recommended due to potential worsening of myotonia.
Describe what is meant by each of the following: [4]
- Facioscapulohumeral Muscular Dystrophy
- Oculopharyngeal Muscular Dystrophy
- Limb-girdle Muscular Dystrophy
- Emery-Dreifuss Muscular Dystrophy
Describe how they present [4]
Facioscapulohumeral Muscular Dystrophy
- Facioscapulohumeral muscular dystrophy usually presents in childhood with weakness around the face, progressing to the shoulders and arms.
- A classic initial symptom is sleeping with their eyes slightly open and weakness in pursing their lips.
- They are unable to blow their cheeks out without air leaking from their mouth.
Oculopharyngeal Muscular Dystrophy
- Oculopharyngeal muscular dystrophy usually presents in late adulthood with weakness of the ocular muscles (around the eyes) and pharynx (around the throat) as the name suggests. It typically presents with bilateral ptosis, restricted eye movement and swallowing problems. Muscles around the limb girdles are also affected to varying degrees.
Limb-girdle Muscular Dystrophy
- Limb-girdle muscular dystrophy usually presents in teenage years with progressive weakness around the limb girdles (hips and shoulders).
Emery-Dreifuss Muscular Dystrophy
- Emery-Dreifuss muscular dystrophy usually presents in childhood with contractures, most commonly in the elbows and ankles.
- Contractures are shortening of muscles and tendons that restrict the range of movement in limbs.
- Patients also suffer with progressive weakness and wasting of muscles, starting with the upper arms and lower legs.
