The intracranial volume refers to the total space inside the skull. The main component of this volume is the brain parenchyma or neural tissue, which makes up the majority of the intracranial volume.

Further Reading:

Intracranial pressure (ICP) refers to the pressure within the craniospinal compartment, which includes neural tissue, blood, and cerebrospinal fluid (CSF). Normal ICP for a supine adult is 5-15 mmHg. The body maintains ICP within a narrow range through shifts in CSF production and absorption. If ICP rises, it can lead to decreased cerebral perfusion pressure, resulting in cerebral hypoperfusion, ischemia, and potentially brain herniation.

The cranium, which houses the brain, is a closed rigid box in adults and cannot expand. It is made up of 8 bones and contains three main components: brain tissue, cerebral blood, and CSF. Brain tissue accounts for about 80% of the intracranial volume, while CSF and blood each account for about 10%. The Monro-Kellie doctrine states that the sum of intracranial volumes is constant, so an increase in one component must be offset by a decrease in the others.

There are various causes of raised ICP, including hematomas, neoplasms, brain abscesses, edema, CSF circulation disorders, venous sinus obstruction, and accelerated hypertension. Symptoms of raised ICP include headache, vomiting, pupillary changes, reduced cognition and consciousness, neurological signs, abnormal fundoscopy, cranial nerve palsy, hemiparesis, bradycardia, high blood pressure, irregular breathing, focal neurological deficits, seizures, stupor, coma, and death.

Measuring ICP typically requires invasive procedures, such as inserting a sensor through the skull. Management of raised ICP involves a multi-faceted approach, including antipyretics to maintain normothermia, seizure control, positioning the patient with a 30º head up tilt, maintaining normal blood pressure, providing analgesia, using drugs to lower ICP (such as mannitol or saline), and inducing hypocapnoeic vasoconstriction through hyperventilation. If these measures are ineffective, second-line therapies like barbiturate coma, optimised hyperventilation, controlled hypothermia, or decompressive craniectomy may be considered.

Severe hypertension, defined as blood pressure greater than 180/120 mmHg, is a condition that prevents the use of thrombolysis. In order to proceed with thrombolysis, it is necessary to lower the patient’s blood pressure to below this level within the designated time frame. Oral medications are unlikely to work quickly enough, so an intravenous antihypertensive agent is required.

One commonly used agent in these situations is labetalol, which is administered intravenously at a dose of 10 mg over 1-2 minutes. This dose can be repeated if necessary, or an infusion can be set up to deliver a continuous dose of 2-8 mg per minute. Once the blood pressure is reduced to less than 180/105 mmHg, thrombolysis can be safely performed.

Alternatively, a nitrate infusion, such as Isoket, can be used in patients who cannot tolerate beta-blockers due to contraindications like asthma, heart block, or cardiac failure. This provides an alternative option for lowering blood pressure in these individuals.

Alteplase (rt-pA) is recommended for the treatment of acute ischaemic stroke in adults if it is administered as soon as possible within 4.5 hours of the onset of stroke symptoms. It is important to exclude intracranial haemorrhage through appropriate imaging techniques before starting the treatment. The initial dose of alteplase is 0.9 mg/kg, with a maximum dose of 90 mg. This dose should be given intravenously over a period of 60 minutes. The first 10% of the dose should be administered through intravenous injection, while the remaining dose should be given through intravenous infusion. For a patient weighing 70 kg, the recommended dose would be 63 mg. For more information, please refer to the NICE guidelines on stroke and transient ischaemic attack in individuals over 16 years old.

The ulnar nerve originates from the medial cord of the brachial plexus, specifically from the C8-T1 nerve roots. It may also carry fibers from C7 on occasion. This nerve has both motor and sensory functions.

In terms of motor function, the ulnar nerve innervates the muscles of the hand, excluding the thenar muscles and the lateral two lumbricals (which are supplied by the median nerve). It also innervates two muscles in the anterior forearm: the flexor carpi ulnaris and the medial half of the flexor digitorum profundus.

Regarding sensory function, the ulnar nerve provides innervation to the anterior and posterior surfaces of the medial one and a half fingers, as well as the associated palm and dorsal hand area. There are three sensory branches responsible for the cutaneous innervation of the ulnar nerve. Two of these branches arise in the forearm and travel into the hand: the palmar cutaneous branch, which innervates the skin of the medial half of the palm, and the dorsal cutaneous branch, which innervates the dorsal skin of the medial one and a half fingers and the associated dorsal hand. The third branch arises in the hand and is called the superficial branch, which innervates the palmar surface of the medial one and a half fingers.

When the ulnar nerve is damaged at the elbow, the flexor carpi ulnaris and the medial half of the flexor digitorum profundus muscles in the anterior forearm will be spared. However, if the ulnar nerve is injured at the wrist, these muscles will be affected. Additionally, when the ulnar nerve is damaged at the elbow, flexion of the wrist can still occur due to the intact median nerve, but it will be accompanied by abduction as the flexor carpi ulnaris adducts the hand. On the other hand, wrist flexion will be unaffected when the ulnar nerve is damaged at the wrist.

The sensory function also differs depending on the site of damage. When the ulnar nerve is damaged at the elbow, all three cutaneous branches will be affected, resulting in complete sensory loss in the areas innervated by the ulnar nerve. However, if the damage occurs at the wrist, the two branches that arise in the forearm may be spared.

Damage to the ulnar nerve at either the elbow or wrist leads to a characteristic claw hand appearance.

Multiple sclerosis is a condition characterized by the demyelination of nerve cells in the brain and spinal cord. It is an autoimmune disease caused by recurring inflammation, primarily affecting individuals in early adulthood. The condition is more prevalent in females, with a ratio of 3:2 compared to males.

There are several risk factors associated with multiple sclerosis. These include being of Caucasian race, living at a greater distance from the equator (as the risk tends to increase further away), having a family history of the disease (with approximately 20% of patients having an affected relative), and smoking. Interestingly, the rates of relapse tend to decrease during pregnancy.

Multiple sclerosis can present in three main patterns. The most common is relapsing and remitting MS, where individuals experience periods without symptoms followed by relapses. This accounts for 80% of cases at the time of diagnosis. Another pattern is primary progressive MS, where symptoms develop and worsen from the beginning with few remissions. This is seen in approximately 10-15% of cases at diagnosis. Lastly, there is secondary progressive MS, which occurs after a relapsing/remitting phase. In this pattern, symptoms worsen with fewer remissions, and it affects around 50% of individuals with relapsing/remitting MS within 10 years of diagnosis.

Certain factors can indicate a more favorable prognosis for individuals with multiple sclerosis. These include having a relapsing/remitting course of the disease, being female, experiencing sensory symptoms, and having an early age at onset.

NICE has emphasized that there are particular symptoms and signs that may indicate specific diseases as the underlying cause of a fever. For instance, bacterial meningitis may be suggested if the following symptoms and signs are present: neck stiffness, bulging fontanelle, decreased level of consciousness, and convulsive status epilepticus. For more information, you can refer to the NICE guidelines on the assessment and initial management of fever in children under 5, as well as the NICE Clinical Knowledge Summary on the management of feverish children.

This patient’s medical history suggests a diagnosis of Guillain-Barré syndrome (GBS). GBS typically presents with initial symptoms of sensory changes or pain, accompanied by muscle weakness in the hands and/or feet. This weakness often spreads to the arms and upper body, affecting both sides. During the acute phase, GBS can be life-threatening, with around 15% of patients experiencing respiratory muscle weakness and requiring mechanical ventilation.

The exact cause of GBS is unknown, but it is believed to involve an autoimmune response where the body’s immune system attacks the myelin sheath surrounding the peripheral nerves. In about 75% of cases, there is a preceding infection, commonly affecting the gastrointestinal or respiratory tracts.

In this particular case, the most likely underlying cause is Campylobacter jejuni, a gastrointestinal pathogen. This is supported by the recent history of a severe diarrheal illness.

This woman is displaying symptoms and signs that are in line with a diagnosis of meningococcal septicaemia. In the United Kingdom, the majority of cases of meningococcal septicaemia are caused by Neisseria meningitidis group B.

The implementation of a vaccination program for Neisseria meningitidis group C has significantly reduced the prevalence of this particular type. However, a vaccine for group B disease is currently undergoing clinical trials and is not yet accessible for widespread use.

Ulnar nerve lesions can be assessed using Froment’s sign. To perform this test, a piece of paper is placed between the patient’s thumb and index finger. The examiner then tries to pull the paper out of the patient’s pinched grip. If the patient has an ulnar nerve palsy, they will struggle to maintain the grip and may compensate by flexing the flexor pollicis longus muscle of the thumb to maintain pressure. This compensation is evident when the patient’s interphalangeal joint of the thumb flexes. Froment’s sign is a useful indicator of ulnar nerve dysfunction.

Alteplase (rt-pA) is recommended for the treatment of acute ischaemic stroke in adults if it is administered as soon as possible within 4.5 hours of the onset of stroke symptoms. It is important to exclude intracranial haemorrhage through appropriate imaging techniques before starting the treatment. The initial dose of alteplase is 0.9 mg/kg, with a maximum dose of 90 mg. This dose should be given intravenously over 60 minutes, with the initial 10% administered by intravenous injection and the remainder by intravenous infusion. In the case of a patient weighing 120 kg, the maximum dose of 90 mg should be administered. For more information, please refer to the NICE guidelines on stroke and transient ischaemic attack in individuals over 16 years old.

Tonsillar herniation occurs when the cerebellar tonsils are pushed through the foramen magnum. This condition is characterized by a decrease in consciousness, respiratory arrest, and flaccid paralysis.

Further Reading:

Intracranial pressure (ICP) refers to the pressure within the craniospinal compartment, which includes neural tissue, blood, and cerebrospinal fluid (CSF). Normal ICP for a supine adult is 5-15 mmHg. The body maintains ICP within a narrow range through shifts in CSF production and absorption. If ICP rises, it can lead to decreased cerebral perfusion pressure, resulting in cerebral hypoperfusion, ischemia, and potentially brain herniation.

The cranium, which houses the brain, is a closed rigid box in adults and cannot expand. It is made up of 8 bones and contains three main components: brain tissue, cerebral blood, and CSF. Brain tissue accounts for about 80% of the intracranial volume, while CSF and blood each account for about 10%. The Monro-Kellie doctrine states that the sum of intracranial volumes is constant, so an increase in one component must be offset by a decrease in the others.

There are various causes of raised ICP, including hematomas, neoplasms, brain abscesses, edema, CSF circulation disorders, venous sinus obstruction, and accelerated hypertension. Symptoms of raised ICP include headache, vomiting, pupillary changes, reduced cognition and consciousness, neurological signs, abnormal fundoscopy, cranial nerve palsy, hemiparesis, bradycardia, high blood pressure, irregular breathing, focal neurological deficits, seizures, stupor, coma, and death.

Measuring ICP typically requires invasive procedures, such as inserting a sensor through the skull. Management of raised ICP involves a multi-faceted approach, including antipyretics to maintain normothermia, seizure control, positioning the patient with a 30º head up tilt, maintaining normal blood pressure, providing analgesia, using drugs to lower ICP (such as mannitol or saline), and inducing hypocapnoeic vasoconstriction through hyperventilation. If these measures are ineffective, second-line therapies like barbiturate coma, optimised hyperventilation, controlled hypothermia, or decompressive craniectomy may be considered.

Cluster headaches are a type of headache that is commonly seen in young men in their 20s. The male to female ratio for this condition is 6:1. Smoking is also known to increase the risk of developing cluster headaches. These headaches occur in clusters, usually lasting for a few weeks every year or two. The pain experienced is severe and typically affects one side of the head, often around or behind the eye. It tends to occur at the same time each day and can cause the patient to become agitated, sometimes resorting to hitting their head against a wall or the floor in an attempt to distract from the pain.

In addition to the intense pain, cluster headaches are also associated with autonomic involvement. This can manifest as various symptoms on the same side as the headache, including conjunctival injection (redness of the eye), rhinorrhea (runny nose), lacrimation (tearing of the eye), miosis (constriction of the pupil), and ptosis (drooping of the eyelid).

On the other hand, migraine with typical aura presents with temporary visual disturbances, such as hemianopia (loss of vision in half of the visual field) or scintillating scotoma (a visual aura that appears as a shimmering or flashing area of distorted vision). Migraine without aura, on the other hand, needs to meet specific criteria set by the International Headache Society. These criteria include having at least five headache attacks lasting between 4 to 72 hours, with the headache having at least two of the following characteristics: unilateral location, pulsating quality, moderate to severe pain intensity, and aggravation by routine physical activity.

During a migraine headache, the patient may also experience symptoms such as nausea and/or vomiting, as well as sensitivity to light (photophobia) and sound (phonophobia). It is important to note that these symptoms should not be attributed to another underlying disorder.

If a patient over the age of 50 presents with a new-onset headache, it raises the possibility of giant cell arteritis (temporal arteritis). Other symptoms and signs that may be associated with this condition include jaw claudication (pain in the jaw when chewing), systemic upset, scalp tenderness, and an elevated erythrocyte sedimentation rate (ESR).

Medication overuse headache is a condition that is suspected when a patient is using multiple medications, often at low doses, without experiencing any relief from their headaches.

NICE has emphasized that there are particular symptoms and indications that may indicate specific diseases as the underlying cause of a fever. In the case of herpes simplex encephalitis, the following symptoms and signs may suggest its presence: the presence of a focal neurological sign, focal seizures, and a decreased level of consciousness. For more information on this topic, you may refer to the NICE guidelines on the assessment and initial management of fever in children under the age of 5, as well as the NICE Clinical Knowledge Summary on the management of feverish children.

The most likely cause of the fainting episode in this 25-year-old third year medical student is vasovagal syncope. Vasovagal syncope is a common type of fainting that occurs in response to certain triggers, such as emotional stress, pain, or seeing blood. In this case, the prolonged delivery and emergency C-section likely triggered the patient’s vasovagal response.

The patient’s symptoms of feeling warm and sweaty before fainting are consistent with vasovagal syncope. During a vasovagal episode, there is a sudden drop in blood pressure and heart rate, leading to a temporary loss of consciousness. The absence of loss of bladder or bowel control and tongue biting further support this diagnosis.

The physical examination findings of no focal neurological deficits and a normal cardiovascular examination also align with vasovagal syncope. Additionally, the blood pressure measurements of 122/74 mmHg when lying down and 120/72 mmHg when standing suggest orthostatic hypotension, which is commonly seen in vasovagal syncope.

Further Reading:

Blackouts, also known as syncope, are defined as a spontaneous transient loss of consciousness with complete recovery. They are most commonly caused by transient inadequate cerebral blood flow, although epileptic seizures can also result in blackouts. There are several different causes of blackouts, including neurally-mediated reflex syncope (such as vasovagal syncope or fainting), orthostatic hypotension (a drop in blood pressure upon standing), cardiovascular abnormalities, and epilepsy.

When evaluating a patient with blackouts, several key investigations should be performed. These include an electrocardiogram (ECG), heart auscultation, neurological examination, vital signs assessment, lying and standing blood pressure measurements, and blood tests such as a full blood count and glucose level. Additional investigations may be necessary depending on the suspected cause, such as ultrasound or CT scans for aortic dissection or other abdominal and thoracic pathology, chest X-ray for heart failure or pneumothorax, and CT pulmonary angiography for pulmonary embolism.

During the assessment, it is important to screen for red flags and signs of any underlying serious life-threatening condition. Red flags for blackouts include ECG abnormalities, clinical signs of heart failure, a heart murmur, blackouts occurring during exertion, a family history of sudden cardiac death at a young age, an inherited cardiac condition, new or unexplained breathlessness, and blackouts in individuals over the age of 65 without a prodrome. These red flags indicate the need for urgent assessment by an appropriate specialist.

There are several serious conditions that may be suggested by certain features. For example, myocardial infarction or ischemia may be indicated by a history of coronary artery disease, preceding chest pain, and ECG signs such as ST elevation or arrhythmia. Pulmonary embolism may be suggested by dizziness, acute shortness of breath, pleuritic chest pain, and risk factors for venous thromboembolism. Aortic dissection may be indicated by chest and back pain, abnormal ECG findings, and signs of cardiac tamponade include low systolic blood pressure, elevated jugular venous pressure, and muffled heart sounds. Other conditions that may cause blackouts include severe hypoglycemia, Addisonian crisis, and electrolyte abnormalities.

This patient has developed Wernicke’s encephalopathy, a condition that is associated with alcohol abuse and other causes of thiamine deficiency. It is important to note that the infusion of glucose-containing intravenous fluids without thiamine in a patient with chronic thiamine deficiency can trigger Wernicke’s encephalopathy. In this particular case, it seems that this is what has occurred.

Wernicke’s encephalopathy is typically characterized by a triad of symptoms, which include acute confusion, ophthalmoplegia, and ataxia. Additionally, other possible features of this condition may include papilloedema, hearing loss, apathy, dysphagia, memory impairment, and hypothermia. It is also common for peripheral neuropathy, primarily affecting the legs, to occur in the majority of cases.

This condition is characterized by the presence of acute capillary haemorrhages, astrocytosis, and neuronal death in the upper brainstem and diencephalon. These abnormalities can be visualized through MRI scanning, although CT scanning is not very useful for diagnosis.

If left untreated, most patients with Wernicke’s encephalopathy will go on to develop a Korsakoff psychosis. This condition is characterized by retrograde amnesia, an inability to form new memories, disordered time perception, and confabulation.

Patients who are suspected to have Wernicke’s encephalopathy should be promptly treated with parenteral thiamine (such as Pabrinex) for a minimum of 5 days. Following the parenteral therapy, oral thiamine should be administered.

Dementia is a condition characterized by a decline in cognitive abilities, such as memory, thinking, and reasoning, that is severe enough to interfere with daily functioning. There are several different causes of dementia, but the leading cause is Alzheimer’s disease. Alzheimer’s disease is a progressive brain disorder that affects memory, thinking, and behavior. It is the most common cause of dementia, accounting for approximately 60-80% of cases.

Further Reading:

Dementia is a progressive and irreversible clinical syndrome characterized by cognitive and behavioral symptoms. These symptoms include memory loss, impaired reasoning and communication, personality changes, and reduced ability to carry out daily activities. The decline in cognition affects multiple domains of intellectual functioning and is not solely due to normal aging.

To diagnose dementia, a person must have impairment in at least two cognitive domains that significantly impact their daily activities. This impairment cannot be explained by delirium or other major psychiatric disorders. Early-onset dementia refers to dementia that develops before the age of 65.

The most common cause of dementia is Alzheimer’s disease, accounting for 50-75% of cases. Other causes include vascular dementia, dementia with Lewy bodies, and frontotemporal dementia. Less common causes include Parkinson’s disease dementia, Huntington’s disease, prion disease, and metabolic and endocrine disorders.

There are several risk factors for dementia, including age, mild cognitive impairment, genetic predisposition, excess alcohol intake, head injury, depression, learning difficulties, diabetes, obesity, hypertension, smoking, Parkinson’s disease, low social engagement, low physical activity, low educational attainment, hearing impairment, and air pollution.

Assessment of dementia involves taking a history from the patient and ideally a family member or close friend. The person’s current level of cognition and functional capabilities should be compared to their baseline level. Physical examination, blood tests, and cognitive assessment tools can also aid in the diagnosis.

Differential diagnosis for dementia includes normal age-related memory changes, mild cognitive impairment, depression, delirium, vitamin deficiencies, hypothyroidism, adverse drug effects, normal pressure hydrocephalus, and sensory deficits.

Management of dementia involves a multi-disciplinary approach that includes non-pharmacological and pharmacological measures. Non-pharmacological interventions may include driving assessment, modifiable risk factor management, and non-pharmacological therapies to promote cognition and independence. Drug treatments for dementia should be initiated by specialists and may include acetylcholinesterase inhibitors, memantine, and antipsychotics in certain cases.

In summary, dementia is a progressive and irreversible syndrome characterized by cognitive and behavioral symptoms. It has various causes and risk factors, and its management involves a multi-disciplinary approach.

Febrile convulsions are harmless, generalized seizures that occur in otherwise healthy children who have a fever due to an infection outside the brain. To diagnose febrile convulsions, the child must be developing normally, the seizure should last less than 20 minutes, have no complex features, and not cause any lasting abnormalities.

The prognosis for febrile convulsions is generally positive. There is a 30 to 50% chance of experiencing recurrent febrile convulsions, with a 10% risk of recurrence within the first 24 hours. The likelihood of developing long-term epilepsy is around 6%.

Complex febrile convulsions are characterized by certain factors. These include focal seizures, seizures lasting longer than 15 minutes, experiencing more than one convulsion during a single fever episode, or the child being left with a focal neurological deficit.

Overall, febrile convulsions are typically harmless and do not cause any lasting damage.

If a child who is experiencing convulsions reaches step 3 of the APLS algorithm and has already been given phenytoin as part of their ongoing treatment, it is recommended to initiate a phenobarbitone infusion. This infusion should be administered at a dosage of 20 mg/kg over a period of 30 to 60 minutes.

The symptoms and signs of strokes can vary depending on which blood vessel is affected. Here is a summary of the main symptoms based on the territory affected:

Anterior cerebral artery: This can cause weakness on the opposite side of the body, with the leg and shoulder being more affected than the arm, hand, and face. There may also be minimal loss of sensation on the opposite side of the body. Other symptoms can include difficulty speaking (dysarthria), language problems (aphasia), apraxia (difficulty with limb movements), urinary incontinence, and changes in behavior and personality.

Middle cerebral artery: This can lead to weakness on the opposite side of the body, with the face and arm being more affected than the leg. There may also be a loss of sensation on the opposite side of the body. Depending on the dominant hemisphere of the brain, there may be difficulties with expressive or receptive language (dysphasia). In the non-dominant hemisphere, there may be neglect of the opposite side of the body.

Posterior cerebral artery: This can cause a loss of vision on the opposite side of both eyes (homonymous hemianopia). There may also be defects in a specific quadrant of the visual field. In some cases, there may be a syndrome affecting the thalamus on the opposite side of the body.

It’s important to note that these are just general summaries and individual cases may vary. If you suspect a stroke, it’s crucial to seek immediate medical attention.

The Parkinson-plus syndromes are a group of neurodegenerative disorders that share similar features with Parkinson’s disease but also have additional clinical characteristics that set them apart from idiopathic Parkinson’s disease (iPD). These syndromes include Multiple System Atrophy (MSA), Progressive Supranuclear Palsy (PSP), Corticobasal degeneration (CBD), and Dementia with Lewy Bodies (DLB).

Multiple System Atrophy (MSA) is a less common condition than iPD and PSP. It is characterized by the loss of cells in multiple areas of the nervous system. MSA progresses rapidly, often leading to wheelchair dependence within 3-4 years of diagnosis. Some distinguishing features of MSA include autonomic dysfunction, bladder control problems, erectile dysfunction, blood pressure changes, early-onset balance problems, neck or facial dystonia, and a high-pitched voice.

To summarize the distinguishing features of the Parkinson-plus syndromes compared to iPD, the following table provides a comparison:

iPD:
– Symptom onset: One side of the body affected more than the other
– Tremor: Typically starts at rest on one side of the body
– Levodopa response: Excellent response
– Mental changes: Depression
– Balance/falls: Late in the disease
– Common eye abnormalities: Dry eyes, trouble focusing

MSA:
– Symptom onset: Both sides equally affected
– Tremor: Not common but may occur
– Levodopa response: Minimal response (but often tried in early stages of disease)
– Mental changes: Depression
– Balance/falls: Within 1-3 years
– Common eye abnormalities: Dry eyes, trouble focusing

PSP:
– Symptom onset: Both sides equally affected
– Tremor: Less common, if present affects both sides
– Levodopa response: Minimal response (but often tried in early stages of disease)
– Mental changes: Personality changes, depression
– Balance/falls: Within 1 year
– Common eye abnormalities: Dry eyes, difficulty in looking downwards

CBD:
– Symptom onset: One side of the body affected more than the other
– Tremor: Not common but may occur
– Levodopa response: Minimal response (but often tried in early stages of disease)
– Mental changes: Depression
– Balance/falls: Within 1-3 years
– Common eye abnormalities: Dry eyes, trouble focusing

This patient presents with a classic case of temporal arteritis, also known as giant cell arteritis (GCA). Temporal arteritis is a chronic condition characterized by inflammation in the walls of medium and large arteries, specifically granulomatous inflammation. It typically affects individuals who are over 50 years old.

The clinical features of temporal arteritis include headache, tenderness in the scalp, jaw claudication, and episodes of sudden blindness or amaurosis fugax (usually occurring in one eye). Some patients may also experience systemic symptoms such as fever, fatigue, loss of appetite, weight loss, and depression.

Temporal arteritis is often associated with polymyalgia rheumatica (PMR) in about 50% of cases. PMR is characterized by stiffness, aching, and tenderness in the upper arms (bilateral) and pain in the pelvic girdle.

Visual loss is an early and significant complication of temporal arteritis, and once it occurs, it rarely improves. Therefore, early treatment with high-dose corticosteroids is crucial to prevent further visual loss and other ischemic complications. If temporal arteritis is suspected, immediate initiation of high-dose glucocorticosteroid treatment (40 – 60 mg prednisolone daily) is necessary. It is also important to arrange an urgent referral for specialist evaluation, including a same-day ophthalmology assessment for those with visual symptoms, and a temporal artery biopsy.

The recommended dose of rectal diazepam for treating a child experiencing convulsions is 0.5 mg per kilogram of body weight.

The NICE recommendations for managing patients with suspected TIA are as follows:

– Offer aspirin (300 mg daily) to individuals who have experienced a suspected TIA, unless there are contraindications. This treatment should be started immediately.
– Immediately refer individuals who have had a suspected TIA for specialist assessment and investigation. They should be seen within 24 hours of the onset of symptoms.
– Avoid using scoring systems, such as ABCD2, to assess the risk of subsequent stroke or determine the urgency of referral for individuals with suspected or confirmed TIA.
– Provide secondary prevention measures, in addition to aspirin, as soon as possible after confirming the diagnosis of TIA.

The NICE recommendations for imaging in individuals with suspected TIA or acute non-disabling stroke are as follows:

– Do not offer CT brain scanning to individuals with suspected TIA, unless there is clinical suspicion of an alternative diagnosis that CT could detect.
– After a specialist assessment in the TIA clinic, consider performing an MRI (including diffusion-weighted and blood-sensitive sequences) to determine the area of ischemia, detect hemorrhage, or identify alternative pathologies. If an MRI is conducted, it should be done on the same day as the assessment.
– Carotid imaging is necessary for all individuals with TIA who, after specialist assessment, are considered candidates for carotid endarterectomy. This imaging should be done urgently.

For more information, refer to the NICE guidelines on stroke and transient ischaemic attack in individuals over 16 years old: diagnosis and initial management.

The most probable diagnosis in this case is a subarachnoid haemorrhage (SAH).

When assessing patients who present with an SAH, there may be focal neurological signs that can indicate the potential location of the aneurysm. Common sites for aneurysms include the bifurcation of the middle cerebral artery, the junction of the anterior communicating cerebral artery, and the junction of the posterior communicating artery with the internal carotid artery. If there is complete or partial palsy of the oculomotor nerve, it suggests the rupture of a posterior communicating artery aneurysm.

While hypertension is a risk factor for SAH, a significant increase in blood pressure may occur as a reflex response following the haemorrhage.

The first-line investigation for SAH is a CT head scan, which can detect over 95% of cases if performed within the first 24 hours. The sensitivity of the scan increases to nearly 100% if done within 6 hours of symptom onset. If the CT head scan is negative and there are no contraindications, a lumbar puncture (LP) should be performed to diagnose SAH. It is recommended to perform the LP at least 12 hours after the onset of headache. It is important to note that approximately 3% of patients with a negative CT scan will be confirmed to have had an SAH after undergoing an LP.

Wernicke’s encephalopathy is a condition that is commonly associated with alcohol abuse and other causes of thiamine deficiency. It is characterized by a classic triad of symptoms, including acute confusion, ophthalmoplegia (paralysis or weakness of the eye muscles), and ataxia (loss of coordination). Additional possible features of this condition may include papilloedema (swelling of the optic disc), hearing loss, apathy, dysphagia (difficulty swallowing), memory impairment, and hypothermia. The majority of cases also experience peripheral neuropathy, which typically affects the legs.

The condition is marked by acute capillary haemorrhages, astrocytosis (increase in the number of astrocytes, a type of brain cell), and neuronal death in the upper brainstem and diencephalon. These abnormalities can be visualized using MRI scanning, while CT scanning is not very useful for diagnosis.

If left untreated, most patients with Wernicke’s encephalopathy will go on to develop a Korsakoff psychosis. This condition is characterized by retrograde amnesia (loss of memory for events that occurred before the onset of amnesia), an inability to form new memories, disordered time perception, and confabulation (fabrication of false memories).

When Wernicke’s encephalopathy is suspected, it is crucial to administer parenteral thiamine (such as Pabrinex) for at least 5 days. Following the parenteral therapy, oral thiamine should be continued.

When there is damage to the facial nerve in the LMN, the patient will experience paralysis in the forehead and will be unable to wrinkle their brow. However, in an upper motor neuron lesion, the frontalis muscle is not affected, so the patient can still furrow their brow normally and their ability to close their eyes and blink is not affected. Lower motor neuron lesions affect the final part of the nerve pathway to all branches of the facial nerve, resulting in paralysis of the forehead and the rest of the face on that side. It is important to note that the speed of onset may provide some clues about the cause of the lesion, but it does not help determine the specific location of the damage.

Further Reading:

Bell’s palsy is a condition characterized by sudden weakness or paralysis of the facial nerve, resulting in facial muscle weakness or drooping. The exact cause is unknown, but it is believed to be related to viral infections such as herpes simplex or varicella zoster. It is more common in individuals aged 15-45 years and those with diabetes, obesity, hypertension, or upper respiratory conditions. Pregnancy is also a risk factor.

Diagnosis of Bell’s palsy is typically based on clinical symptoms and ruling out other possible causes of facial weakness. Symptoms include rapid onset of unilateral facial muscle weakness, drooping of the eyebrow and corner of the mouth, loss of the nasolabial fold, otalgia, difficulty chewing or dry mouth, taste disturbance, eye symptoms such as inability to close the eye completely, dry eye, eye pain, and excessive tearing, numbness or tingling of the cheek and mouth, speech articulation problems, and hyperacusis.

When assessing a patient with facial weakness, it is important to consider other possible differentials such as stroke, facial nerve tumors, Lyme disease, granulomatous diseases, Ramsay Hunt syndrome, mastoiditis, and chronic otitis media. Red flags for these conditions include insidious and painful onset, duration of symptoms longer than 3 months with frequent relapses, pre-existing risk factors, systemic illness or fever, vestibular or hearing abnormalities, and other cranial nerve involvement.

Management of Bell’s palsy involves the use of steroids, eye care advice, and reassurance. Steroids, such as prednisolone, are recommended for individuals presenting within 72 hours of symptom onset. Eye care includes the use of lubricating eye drops, eye ointment at night, eye taping if unable to close the eye at night, wearing sunglasses, and avoiding dusty environments. Reassurance is important as the majority of patients make a complete recovery within 3-4 months. However, some individuals may experience sequelae such as facial asymmetry, gustatory lacrimation, inadequate lid closure, brow ptosis, drooling, and hemifacial spasms.

Antiviral treatments are not currently recommended as a standalone treatment for Bell’s palsy, but they may be given in combination with corticosteroids on specialist advice. Referral to an ophthalmologist is necessary if the patient has eye symptoms such as pain, irritation, or itch.

The median nerve originates from the lateral and medial cords of the brachial plexus and receives contributions from the ventral roots of C5-C7 (lateral cord) and C8 and T1 (medial cord). It serves both motor and sensory functions.

In terms of motor function, the median nerve innervates the flexor muscles in the anterior compartment of the forearm, excluding the flexor carpi ulnaris and a portion of the flexor digitorum profundus, which are instead innervated by the ulnar nerve. Additionally, it innervates the thenar muscles and the lateral two lumbricals.

Regarding sensory function, the median nerve gives rise to the palmar cutaneous branch, which provides innervation to the lateral part of the palm. It also gives rise to the digital cutaneous branch, which innervates the lateral three and a half fingers on the palmar surface of the hand.

Within the forearm, the median nerve branches into two major branches: the anterior interosseous nerve (AIN) and the palmar cutaneous branch. The AIN supplies the flexor pollicis longus, pronator quadratus, and the lateral half of the flexor digitorum profundus. On the other hand, the palmar cutaneous branch provides sensory innervation to the skin of the radial palm.

Differentiating between damage to the median nerve at the elbow and wrist can be done by considering these two branches. Injury at the elbow affects these branches, while injury at the wrist spares them. It is important to note that the palmar cutaneous branch remains functional in carpal tunnel syndrome as it travels superficial to the flexor retinaculum. However, it can be damaged by laceration at the wrist.

A comparison of median nerve lesions at the wrist and elbow is presented in the table below:

Median nerve at elbow:
– Motor loss: Weak wrist flexion and abduction, loss of thumb abduction and opposition, loss of flexion of index and middle fingers
– Sensory loss: Lateral 3 and ½ fingers and nail beds, lateral side of palm
– Hand deformity: Ulnar deviation of wrist, thenar wasting, papal benediction on flexing fingers

Median nerve at wrist:
– Motor loss: Loss of thumb abduction and opposition, wrist and finger flexion intact (due to intact AIN)
– Sensory loss: Lateral 3 and ½ fingers and nail beds, lateral side of palm (but can be preserved depending upon palmar cutaneous branch)
– Hand deformity: Thenar wasting, no ulnar deviation of wrist or papal benediction (due to intact AIN)

The symptoms and signs of strokes can vary depending on which blood vessel is affected. Here is a summary of the main symptoms based on the territory affected:

Anterior cerebral artery: This can cause weakness on the opposite side of the body, with the leg and shoulder being more affected than the arm, hand, and face. There may also be minimal loss of sensation on the opposite side of the body. Other symptoms can include difficulty speaking (dysarthria), language problems (aphasia), apraxia (difficulty with limb movements), urinary incontinence, and changes in behavior and personality.

Middle cerebral artery: This can lead to weakness on the opposite side of the body, with the face and arm being more affected than the leg. There may also be a loss of sensation on the opposite side of the body. Depending on the dominant hemisphere of the brain, there may be difficulties with expressive or receptive language (dysphasia). In the non-dominant hemisphere, there may be neglect of the opposite side of the body.

Posterior cerebral artery: This can cause a loss of vision on the opposite side of both eyes (homonymous hemianopia). There may also be defects in a specific quadrant of the visual field. In some cases, there may be a syndrome affecting the thalamus on the opposite side of the body.

It’s important to note that these are just general summaries and individual cases may vary. If you suspect a stroke, it’s crucial to seek immediate medical attention.

Abducens nerve palsy is often linked to extradural hematoma. When there is a mass effect, downward brain herniation can occur, leading to the involvement of the 6th cranial nerve (abducens nerve, CN VI). This nerve controls the lateral rectus muscle, which is responsible for eye abduction. When the abducens nerve is affected, the lateral rectus muscle is unable to function properly, resulting in an inward turning of the affected eye towards the nose (esotropia).

Further Reading:

Extradural haematoma (EDH) is a collection of blood that forms between the inner surface of the skull and the outer layer of the dura, the dura mater. It is typically caused by head trauma and is often associated with a skull fracture, with the pterion being the most common site of injury. The middle meningeal artery is the most common source of bleeding in EDH.

Clinical features of EDH include a history of head injury with transient loss of consciousness, followed by a lucid interval and gradual loss of consciousness. Other symptoms may include severe headache, sixth cranial nerve palsies, nausea and vomiting, seizures, signs of raised intracranial pressure, and focal neurological deficits.

Imaging of EDH typically shows a biconvex shape and may cause mass effect with brain herniation. It can be differentiated from subdural haematoma by its appearance on imaging.

Management of EDH involves prompt referral to neurosurgery for evacuation of the haematoma. In some cases with a small EDH, conservative management may be considered. With prompt evacuation, the prognosis for EDH is generally good.

Henry’s law describes the correlation between the quantity of dissolved gas in a liquid and its partial pressure above the liquid. According to Henry’s law, the amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid. In the case of nitrogen narcosis, as the patient descends deeper into the water, the pressure increases, causing more nitrogen to dissolve in the bloodstream. As the patient ascends, the pressure decreases, leading to a decrease in the amount of dissolved nitrogen and improvement in symptoms.

Further Reading:

Decompression illness (DCI) is a term that encompasses both decompression sickness (DCS) and arterial gas embolism (AGE). When diving underwater, the increasing pressure causes gases to become more soluble and reduces the size of gas bubbles. As a diver ascends, nitrogen can come out of solution and form gas bubbles, leading to decompression sickness or the bends. Boyle’s and Henry’s gas laws help explain the changes in gases during changing pressure.

Henry’s law states that the amount of gas that dissolves in a liquid is proportional to the partial pressure of the gas. Divers often use atmospheres (ATM) as a measure of pressure, with 1 ATM being the pressure at sea level. Boyle’s law states that the volume of gas is inversely proportional to the pressure. As pressure increases, volume decreases.

Decompression sickness occurs when nitrogen comes out of solution as a diver ascends. The evolved gas can physically damage tissue by stretching or tearing it as bubbles expand, or by provoking an inflammatory response. Joints and spinal nervous tissue are commonly affected. Symptoms of primary damage usually appear immediately or soon after a dive, while secondary damage may present hours or days later.

Arterial gas embolism occurs when nitrogen bubbles escape into the arterial circulation and cause distal ischemia. The consequences depend on where the embolism lodges, ranging from tissue ischemia to stroke if it lodges in the cerebral arterial circulation. Mechanisms for distal embolism include pulmonary barotrauma, right to left shunt, and pulmonary filter overload.

Clinical features of decompression illness vary, but symptoms often appear within six hours of a dive. These can include joint pain, neurological symptoms, chest pain or breathing difficulties, rash, vestibular problems, and constitutional symptoms. Factors that increase the risk of DCI include diving at greater depth, longer duration, multiple dives close together, problems with ascent, closed rebreather circuits, flying shortly after diving, exercise shortly after diving, dehydration, and alcohol use.

Diagnosis of DCI is clinical, and investigations depend on the presentation. All patients should receive high flow oxygen, and a low threshold for ordering a chest X-ray should be maintained. Hydration is important, and IV fluids may be necessary. Definitive treatment is recompression therapy in a hyperbaric oxygen chamber, which should be arranged as soon as possible. Entonox should not be given, as it will increase the pressure effect in air spaces.