Day: March 22, 2024

Overview Vasovagal syncope is a form of ‘reflex syncope’ more colloquially known as a ‘common faint’. Syncope is a broad term for transient loss of consciousness. The loss of consciousness is usually due to a brief reduction in cerebral perfusion due to an abrupt fall in blood pressure. The loss of consciousness inevitably leads to a collapse with subsequent recovery as perfusion is restored (average 12 seconds). There are many different causes of syncope of which the most common is vasovagal syncope. Vasovagal syncope is also known as a ‘common faint’ and typically occurs in the setting of a stressful event (e.g.

Overview Vascular dementia is a common form of dementia caused by cerebrovascular disease. Vascular dementia (VD) refers to a subtype of dementia that is primarily caused by cerebrovascular disease (CVD). CVD refers to vascular brain injury or dysfunction as a result of conditions that impair cerebral blood flow including chronic small vessel disease, stroke or haemorrhage. It is the second most common form of dementia in the UK affecting around 150,000 people. It is commonly part of ‘mixed dementia’ a combination of Alzheimer’s disease (AD) and VD. Dementia Dementia describes a clinical syndrome that is characterised by a significant deterioration in

Overview Trigeminal neuralgia is characterised by episodes of acute severe facial pain within the distribution of the trigeminal nerve. Once termed tic douloureux, trigeminal neuralgia is a rare condition that most commonly affects the maxillary and mandibular branches of the trigeminal nerve. Episodes normally last seconds to a few minutes and may be triggered by cold wind, talking, vibrations Typically the condition is unilateral though it is bilateral in 3%. Epidemiology Trigeminal neuralgia is a rare condition that is more common in women. The exact incidence of trigeminal is unclear. Annual incidence in the UK is estimated to be 8 per 10,000 although

Overview Transient ischaemic attack is a cerebrovascular event that is caused by abnormal perfusion of cerebral tissue. TIA is defined as transient neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without evidence of acute infarction. It is a medical emergency, within the first week following a TIA, the risk of stroke is up to 10%. The estimated incidence of TIA within the UK is 50 per 100,000 people per year. Traditionally, transient neurological dysfunction with resolution within 24 hours was diagnostic of TIA. However, up to a third of patients whose symptoms have resolved within 24 hours have

Introduction A third nerve palsy refers to damage to the oculomotor cranial nerve. The oculomotor nerve is the third cranial nerve that has predominant motor function to the pupil, eyelid and extraocular muscles. Paralysis or ‘palsy’ to the oculomotor nerve can occur anywhere along its course from nucleus in the midbrain to orbital apex. Anatomy & physiology The third nerve nucleus originates in the midbrain of the brainstem. Nerve course The third nerve nucleus is comprised of several subnuclei that innervate important visual structures. Fibres from these nuclei pass from the midbrain into the subarachnoid space and then into the lateral wall of the cavernous

Overview Tension-type headache is a common primary headache disorder. Tension-type headaches can occur sporadically or represent a debilitating chronic illness. Onset tends to be in a patients’ 20’s, and gradually becomes less common with advancing age. It is a clinical diagnosis based on criteria outined by the International Headache Society (detailed below). It is important to consider and exclude sinister, secondary causes of any headache. Treatment tends to target symptomatic relief. The benefits of prophylactic therapies are modest at best. Diagnosis Tension-type headaches may be classified as episodic (infrequent, frequent) or chronic. The International Headache Society classify tension headaches in their International Classification of Headache Disorders –

Overview A stroke is a cerebrovascular event that is caused by abnormal perfusion of cerebral tissue. Stroke is a common medical emergency that requires urgent recognition and treatment. The total number of strokes each year is estimated at 110,000 and the mortality from a first-ever stroke is 11%. Strokes can broadly be categorised as: Ischaemic: caused by occlusion of blood vessels, most common accounting for 85% of cases. Haemorrhagic: result from bleeding, accounts for 15% of cases. Stroke is a defined as a clinical syndrome characterised by sudden onset of rapidly developing focal or global neurological disturbance, which lasts more than

Overview Status epilepticus refers to continuous seizure activity, which has failed to self-terminate. Status epilepticus (SE) or ‘status’ is medical emergency. More than 15% of patients with epilepsy will have at least one episode of SE, which can be life-threatening. It is traditionally defined by the duration of continuous seizure activity and effect on consciousness. Traditional definition A single epileptic seizure lasting > 30 minutes A run of epileptic seizures (≥2) without regaining consciousness between episodes The majority of seizures will spontaneously terminate within 3 minutes and do not require emergency treatment. However, those with sustained seizures are at risk of long-term neurological damage. The highest

Overview A sixth cranial nerve palsy refers to dysfunction of the abducens nerve that causes a lateral rectus palsy. The abducens nerve is the sixth (VI) cranial nerve, which provides innervation to the lateral rectus muscle. This is one of the extra-ocular muscles that causes eye abduction, which is needed for horizontal gaze. A VI nerve palsy is the most common cranial nerve palsy in isolation. A palsy can develop due to a lesion anywhere along the path of the nerve from pons to lateral rectus muscle. Anatomy & physiology The abducens nerve innervates the lateral rectus muscle. Nerve course The sixth

Overview Polyneuropathy refers to damage or dysfunction of multiple nerves of the peripheral nervous system. Polyneuropathy is a broad term that refers to the involvement of multiple peripheral nerves. It is a type of peripheral neuropathy and the two terms are often used synonymously. However, this is imprecise as there are many different types of peripheral neuropathy (e.g. radiculopathy, mononeuropathy) that simply refers to damage or dysfunction of peripheral nerves. Polyneuropathies typically lead to symmetrical involvement of distal peripheral nerves in a ‘length-dependent’ manner, meaning the longer nerves of the legs and arms are affected first. Symptoms are usually those of

Overview Peripheral neuropathy is a broad term that refers to any disorder of the peripheral nervous system. Peripheral neuropathy is a broad term that refers to damage to any of the peripheral nerves that make up the peripheral nervous system. The human nervous system is broadly divided into central and peripheral. Central nervous system: this encompasses the brain and spinal cord Peripheral nervous system: this encompasses the cranial nerves, spinal nerves, spinal roots, plexuses, peripheral nerves, and the neuromuscular junctions The peripheral nervous system is important for passing information to and from the central nervous system. Nerves within the peripheral nervous

Overview Parkinson’s disease is a chronic, progressive neurodegenerative condition that occurs secondary to loss of dopaminergic neurones within the substantia nigra. Parkinson’s disease is the most common form of parkinsonism. Parkinsonism describes the presence of bradykinesia and at least one of the following: Resting tremor Rigidity Postural instability Parkinson’s disease tends to present with unilateral symptoms at onset with gradual progression and the development of bilateral signs. In addition to the motor symptoms, non-motor complications like depression, dementia, sleep disturbance and autonomic dysfunction cause significant ill-health. Management may consist of medical therapy (e.g. levodopa) and surgical interventions (e.g. deep brain stimulation). Epidemiology Parkinson’s disease is

Overview Myasthenia gravis is a neuromuscular disorder, which is characterised by weakness and fatiguability. Myasthenia gravis (MG) is a relatively uncommon autoimmune disorder, which is due to antibody-mediated blockage of neuromuscular transmission. MG is predominantly due to the formation acetylcholine receptor antibodies (AChR-Ab) that bind to acetylcholine (ACh) receptors at the neuromuscular junction (NMJ). This prevents binding of ACh and subsequent depolarisation needed for muscular contraction. The hallmark of MG is fatiguability, which refers to increasing muscle weakness with repeated use. Epidemiology The prevalence of MG is estimated at 15 per 100,000 population within the UK. MG has a variable annual incidence of 7-23

Overview Multiple sclerosis is a chronic, immune-mediated inflammatory disease of the central nervous system. Multiple sclerosis (MS) is a demyelinating neuroinflammatory condition, which affects the central nervous system (CNS). The CNS comprises the brain, brainstem and spinal cord. The condition is most commonly seen in young adults. Demyelination, which is the hallmark of MS, refers to damage to the protective myelin sheath that surrounds neurons. This can lead to scarring and secondary neuronal cell loss, which results in irreversible neurological damage. Due to the wide area of the CNS that can be affected, MS can present with a range of clinical manifestations

Overview A mononeuropathy refers to damage or dysfunction of a single peripheral nerve. Mononeuropathy is a broad term that refers to damage or dysfunction of a single peripheral nerve. This typically leads to a characteristic set of clinical features with motor and/or sensory dysfunction relating to the usual function of the nerve involved. Mononeuropathies are commonly due to entrapment or compression as peripheral nerves have to travels through small openings and between other major structures (e.g. median nerve compression within the carpal tunnel). This compression may be internal (e.g. nerve tumour), or external (e.g. fracture, compressive clothing, unusual posture). Management of

Overview Migraine is a form of primary headache disorder. Migraine describes a recurrent moderate to severe headache commonly associated with nausea, vomiting, photophobia and phonophobia. The headache is typically unilateral and pulsating in nature lasting 4-72 hours. There are two major types of migraine: Migraine without aura: characteristic migraine headache with associated symptoms. Migraine with aura: a migraine headache that is preceded (and sometimes accompanied) by focal neurological symptoms. Migraines are one of the most common disabling conditions in the world. In the 2019 Global Burden of Disease study, headaches (primarily migraine and tension-type headache) were ranked the 14th most common

Introduction Dementia with Lewy body is a common form of dementia characterised by the finding of Lewy bodies on pathology. Dementia with Lewy body (DLB), also known as Lewy body dementia, is a common subtype of dementia that is characterised by the histopathological findings of intracytoplasmic inclusions known as Lewy bodies that contain alpha-synuclein. It is a distinctive form of dementia due to its clinical features. Typical features of DLB include visual hallucinations, parkinsonism, cognitive fluctuations, dysautonomia (abnormalities in the autonomic nervous system), sleep disorders, and sensitivity to antipsychotic medications (i.e. neuroleptics). Dementia Dementia describes a clinical syndrome that is characterised

Overview Idiopathic intracranial hypertension is a disorder characterised by features of raised intracranial pressure. Idiopathic intracranial hypertension (IIH) is a disorder caused by chronically elevated intracranial pressure (ICP), which leads to the characteristic clinical features of headache, papilloedema (swollen optic discs) and visual loss. The actual cause of the condition remains unknown, but it primarily affects overweight women of childbearing age. Several older terms have been used for IIH: Pseudotumor cerebri: cerebral tumours classically cause raised intracranial pressure Benign intracranial hypertension: renamed because the condition can be disabling and cause loss of sight Epidemiology The annual incidence of IIH is approximately 1-2

Introduction Huntington’s disease (HD) is an autosomal-dominantly inherited, neurodegenerative condition characterised by chorea, dystonia and cognitive changes. Symptoms tend to develop between the ages of 20-40, choreiform movements are characteristic. It is a progressive disorder that often results in death within 20 years of onset. HD is caused by an increased number of cysteine-adenosine-guanine (CAG) trinucleotide repeats within the huntingtin gene on chromosome 4. Treatment is aimed at reducing symptoms and preserving quality of life, currently there are no intervention cure or halt disease progression. Epidemiology HD is estimated to have a prevalence of 2-5 per 100,000 worldwide. Onset tends to be in

Overview Horner’s syndrome refers to a classic triad of miosis, ptosis and anhidrosis. Horner’s syndrome is a classic medical condition that is characterised by a unilateral triad of: Miosis: small pupil Ptosis: drooping eyelid Anhidrosis: lack of sweat Horner’s syndrome is due to a lesion anywhere along the sympathetic pathway, also known as the oculosympathetic pathway. This pathway is important for pupillary dilatation. As such, Horner’s is also known as oculosympathetic paresis. Pupillary response The sympathetic nervous system has an important role in pupillary dilatation. Both the sympathetic and parasympathetic nervous systems are involved in pupillary responses. This helps to control how much

Overview Guillain-Barré syndrome is an acute, inflammatory polyneuropathy typically characterised by a progressive, ascending neuropathy resulting in weakness and reduced reflexes. GBS is a rare neuropathy classically presenting with progressive lower limb weakness. The majority of patients have history of a preceding illness (typically gastroenteritis or flu-like illness). GBS is an umbrella term that refers to a number of ‘variants’ with unique features and pathogenesis. Acute inflammatory demyelinating polyneuropathy (AIDP) is the most common form accounting for 90% of disease. The condition has a spectrum of severity and may be treated with plasma exchange or IV immunoglobulin. Those with severe disease can require mechanical

Overview Frontotemporal dementia is a neurodegenerative disorder characterised by focal degeneration of the frontal & temporal lobes. Frontotemporal dementia (FTD) is a type of dementia that is characterised by predominant disturbances in social behaviour, personality and language (e.g. aphasia). This is accompanied by preferential degeneration of frontal and temporal lobes. FTD is a heterogeneous condition with various subtypes. It is an uncommon cause of dementia, but typically affects patients at a younger age (< 65 years). Dementia Dementia describes a clinical syndrome that is characterised by a significant deterioration in mental function that leads impairment of normal function. In healthcare, we measure ‘normal function’ by activities

Overview Essential tremor is a type of action tremor that is very common in the general population. Essential tremor is considered the most common type of action tremor (i.e. tremor during voluntary muscle contraction) that typically involves the hands and is bought out by anti-gravity positions (e.g. outstretched hands). Essential tremor is associated with family history and often shows an autosomal dominant pattern of inheritance. It was previously termed ‘benign essential tremor’, however, the term benign has been dropped because it can cause a severe and disabling tremor in some individuals. Epidemiology A family history of essential tremor may be observed

Overview Epilepsy is a chronic neurological disorder, which is characterised by recurrent seizures. Epilepsy is characterised by development of multiple seizures. A seizure refers to a transient neurological change due to synchronous, hyperexcited neuronal activity in the brain. Clinically, this manifests as a transient occurrence of seizure-like activity. This ‘activity’ may refer to a disturbance of consciousness, motor function, emotion, behaviour, cognition or sensation. Epilepsy is a common neurological disorder that affects > 70 million people globally. The lifetime risk of having a single seizure is 1 in 10, whereas the lifetime risk of having epilepsy is 3%. Aetiology The cause of epilepsy is unknown in up to

Overview Encephalitis is a broad term that refers to inflammation of the brain parenchyma. There are many different aetiologies of encephalitis which characteristically presents with abnormal brain function. This is suggested by altered mental status, motor/sensory deficits, personality change, or even speech alteration. Encephalitis may be due to a wide variety of pathologies including viral, post-infective, bacterial, autoimmune, or paraneoplastic. It is therefore important to keep an open mind. The most important infective aetiology to exclude is herpes simplex virus (HSV) encephalitis that is usually fatal without treatment. Epidemiology The true incidence of encephalitis is unknown because many cases are unreported or

Introduction Dementia is a clinical syndrome characterised by a significant deterioration in mental function that leads to impairment of normal function. Dementia describes a clinical syndrome that is characterised by a significant deterioration in mental function. This subsequently impairs an individual to carry out normal functions. In healthcare, we measure ‘normal function’ by activities of daily living (ADLs). These are a series of routine activities that people should be able to do without assistance. They can be broadly divided into personal tasks and domestic tasks. Personal: washing, dressing, toileting, continence, transferring (e.g. bed to chair) Domestic: cooking, cleaning, shopping, managing finances,