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Question 1
Incorrect
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Which of these openings allows the facial nerve to enter the temporal bone?
Your Answer: Foramen lacerum
Correct Answer: Internal acoustic meatus
Explanation:The facial nerve passes through the internal acoustic meatus of the temporal bone and emerges from the stylomastoid foramen.
The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron issues like Bell’s palsy and upper motor neuron issues like stroke.
The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve’s path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.
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This question is part of the following fields:
- Neurological System
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Question 2
Correct
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You are a medical student on an endocrine ward. There is a 65-year-old patient on the ward suffering from hypopituitarism. One of the junior doctors explains to you that the patient's pituitary gland was damaged when they received radiation therapy for a successfully treated brain tumour last year. He shows you a CT scan and demonstrates that only the anterior pituitary gland is damaged, with the posterior pituitary gland unaffected.
Which of the following hormones is unlikely to be affected?Your Answer: antidiuretic hormone
Explanation:The pituitary gland is a small gland located within the sella turcica in the sphenoid bone of the middle cranial fossa. It weighs approximately 0.5g and is covered by a dural fold. The gland is attached to the hypothalamus by the infundibulum and receives hormonal stimuli from the hypothalamus through the hypothalamo-pituitary portal system. The anterior pituitary, which develops from a depression in the wall of the pharynx known as Rathkes pouch, secretes hormones such as ACTH, TSH, FSH, LH, GH, and prolactin. GH and prolactin are secreted by acidophilic cells, while ACTH, TSH, FSH, and LH are secreted by basophilic cells. On the other hand, the posterior pituitary, which is derived from neuroectoderm, secretes ADH and oxytocin. Both hormones are produced in the hypothalamus before being transported by the hypothalamo-hypophyseal portal system.
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This question is part of the following fields:
- Neurological System
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Question 3
Correct
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A 45-year-old female presents to the neurology clinic with diplopia and headache. Upon examination, her visual acuity is 6/6, and there is pupillary dilatation. An MRI of her head reveals a post-communicating artery aneurysm. What cranial nerve palsy is probable in this patient?
Your Answer: Third nerve palsy
Explanation:A third nerve palsy may be caused by an aneurysm in the posterior communicating artery.
Understanding Third Nerve Palsy: Causes and Features
Third nerve palsy is a neurological condition that affects the third cranial nerve, which controls the movement of the eye and eyelid. The condition is characterized by the eye being deviated ‘down and out’, ptosis, and a dilated pupil. In some cases, it may be referred to as a ‘surgical’ third nerve palsy due to the dilation of the pupil.
There are several possible causes of third nerve palsy, including diabetes mellitus, vasculitis (such as temporal arteritis or SLE), uncal herniation through tentorium if raised ICP, posterior communicating artery aneurysm, and cavernous sinus thrombosis. In some cases, it may also be a false localizing sign. Weber’s syndrome, which is characterized by an ipsilateral third nerve palsy with contralateral hemiplegia, is caused by midbrain strokes. Other possible causes include amyloid and multiple sclerosis.
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This question is part of the following fields:
- Neurological System
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Question 4
Correct
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Sarah, a 65-year-old woman, undergoes a routine MRI scan of her head due to persistent headaches. The scan reveals a small lesion situated on the right side of the cerebellum. Although Sarah does not exhibit any neurological symptoms at present, she is worried about the potential development of symptoms if the lesion is left untreated.
What part of the body is most likely to experience symptoms in Sarah's situation?Your Answer: Left side of his body
Explanation:If Mark has a unilateral cerebellar lesion, he is likely to experience symptoms on the same side of his body as the lesion, which would be the left side in this case. The signs associated with cerebellar lesions include dysdiadochokinesia & dysmetria, ataxia, nystagmus, intention tremor, slurred speech, and hypotonia, and they would be more pronounced on the affected side of the body. As the lesion grows and affects both hemispheres, both sides of the body may become affected, but initially, left-sided symptoms are more likely. It is unlikely that Mark would develop right-sided symptoms, as this would be contralateral to the lesion. The location of the lesion within each hemisphere determines whether the upper or lower parts of the body are more affected.
Cerebellar syndrome is a condition that affects the cerebellum, a part of the brain responsible for coordinating movement and balance. When there is damage or injury to one side of the cerebellum, it can cause symptoms on the same side of the body. These symptoms can be remembered using the mnemonic DANISH, which stands for Dysdiadochokinesia, Dysmetria, Ataxia, Nystagmus, Intention tremour, Slurred staccato speech, and Hypotonia.
There are several possible causes of cerebellar syndrome, including genetic conditions like Friedreich’s ataxia and ataxia telangiectasia, neoplastic growths like cerebellar haemangioma, strokes, alcohol use, multiple sclerosis, hypothyroidism, and certain medications or toxins like phenytoin or lead poisoning. In some cases, cerebellar syndrome may be a paraneoplastic condition, meaning it is a secondary effect of an underlying cancer like lung cancer. It is important to identify the underlying cause of cerebellar syndrome in order to provide appropriate treatment and management.
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This question is part of the following fields:
- Neurological System
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Question 5
Incorrect
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A 76-year-old man is scheduled for an internal carotid artery endarterectomy. During the dissection, which nervous structure is most vulnerable?
Your Answer: Recurrent laryngeal nerve
Correct Answer: Hypoglossal nerve
Explanation:The carotid endarterectomy procedure poses a risk to several nerves, including the hypoglossal nerve, greater auricular nerve, and superior laryngeal nerve. The dissection of the sternocleidomastoid muscle, ligation of the common facial vein, and exposure of the common and internal carotid arteries can all potentially damage these nerves. However, the sympathetic chain located posteriorly is less susceptible to injury during this operation.
The internal carotid artery originates from the common carotid artery near the upper border of the thyroid cartilage and travels upwards to enter the skull through the carotid canal. It then passes through the cavernous sinus and divides into the anterior and middle cerebral arteries. In the neck, it is surrounded by various structures such as the longus capitis, pre-vertebral fascia, sympathetic chain, and superior laryngeal nerve. It is also closely related to the external carotid artery, the wall of the pharynx, the ascending pharyngeal artery, the internal jugular vein, the vagus nerve, the sternocleidomastoid muscle, the lingual and facial veins, and the hypoglossal nerve. Inside the cranial cavity, the internal carotid artery bends forwards in the cavernous sinus and is closely related to several nerves such as the oculomotor, trochlear, ophthalmic, and maxillary nerves. It terminates below the anterior perforated substance by dividing into the anterior and middle cerebral arteries and gives off several branches such as the ophthalmic artery, posterior communicating artery, anterior choroid artery, meningeal arteries, and hypophyseal arteries.
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This question is part of the following fields:
- Neurological System
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Question 6
Incorrect
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A 50-year-old man visits the clinic with a complaint of gradual hearing loss over the past nine months. He works in construction and initially attributed it to the use of loud power tools, despite always wearing ear protection. He also reports experiencing a high-pitched ringing in his ears for the same duration. Recently, he has been experiencing episodes of dizziness where he feels like the room is spinning. Otoscopy reveals no abnormalities. During the Rinne and Weber tests, the Rinne test is positive bilaterally, and the sound is louder on the left. What conclusions can be drawn from these findings?
Your Answer: Conductive hearing loss on the left.
Correct Answer: Sensorineural hearing loss on the right.
Explanation:The patient in the question has a sensorineural hearing loss on the right side. The Rinne and Weber tests were used to determine the type and affected side of the hearing loss. The Rinne test was positive bilaterally, indicating normal hearing or a sensorineural deficit on one or both sides. The Weber test was heard better on the left, indicating a conductive hearing loss on the left or a sensorineural hearing loss on the right. As a conductive hearing loss was ruled out with the Rinne test, the patient must have a right-sided sensorineural deficit. This is suggestive of a vestibular schwannoma, a benign tumor of the vestibulocochlear nerve, which can cause gradual unilateral hearing loss, tinnitus, and vertigo.
Vestibular schwannomas, also known as acoustic neuromas, make up about 5% of intracranial tumors and 90% of cerebellopontine angle tumors. These tumors typically present with a combination of vertigo, hearing loss, tinnitus, and an absent corneal reflex. The specific symptoms can be predicted based on which cranial nerves are affected. For example, cranial nerve VIII involvement can cause vertigo, unilateral sensorineural hearing loss, and unilateral tinnitus. Bilateral vestibular schwannomas are associated with neurofibromatosis type 2.
If a vestibular schwannoma is suspected, it is important to refer the patient to an ear, nose, and throat specialist urgently. However, it is worth noting that these tumors are often benign and slow-growing, so observation may be appropriate initially. The diagnosis is typically confirmed with an MRI of the cerebellopontine angle, and audiometry is also important as most patients will have some degree of hearing loss. Treatment options include surgery, radiotherapy, or continued observation.
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This question is part of the following fields:
- Neurological System
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Question 7
Correct
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Which one of the following structures is not at the level of the infrapyloric plane?
Your Answer: Cardioesophageal junction
Explanation:The cardioesophageal junction is located at the level of T11, which is a frequently tested anatomical knowledge. The oesophagus spans from the lower border of the cricoid cartilage at C6 to the cardioesophageal junction at T11. It is important to note that in newborns, the oesophagus extends from C4 or C5 to T9.
Anatomical Planes and Levels in the Human Body
The human body can be divided into different planes and levels to aid in anatomical study and medical procedures. One such plane is the transpyloric plane, which runs horizontally through the body of L1 and intersects with various organs such as the pylorus of the stomach, left kidney hilum, and duodenojejunal flexure. Another way to identify planes is by using common level landmarks, such as the inferior mesenteric artery at L3 or the formation of the IVC at L5.
In addition to planes and levels, there are also diaphragm apertures located at specific levels in the body. These include the vena cava at T8, the esophagus at T10, and the aortic hiatus at T12. By understanding these planes, levels, and apertures, medical professionals can better navigate the human body during procedures and accurately diagnose and treat various conditions.
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This question is part of the following fields:
- Neurological System
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Question 8
Incorrect
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A 55-year-old man comes to his physician complaining of severe morning headaches. The doctor conducts a neurological evaluation to detect any neurological impairments. During the assessment, the patient exhibits normal responses for all tests except for the absence of corneal reflex.
Which cranial nerve is impacted?Your Answer: Optic nerve
Correct Answer: Trigeminal nerve
Explanation:The loss of corneal reflex is associated with the trigeminal nerve, specifically the ophthalmic branch. This reflex tests the sensation of the eyeball when cotton wool is used to touch it, causing the eye to blink in response. The glossopharyngeal nerve is not associated with the eye but is involved in the gag reflex. The optic nerve is responsible for vision and does not provide physical sensation to the eyeball. The oculomotor nerve is primarily a motor nerve and only provides sensory information in response to bright light. The trochlear nerve is purely motor and has no sensory innervations.
Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 9
Correct
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Following the discovery of a pituitary tumour in a 32-year-old woman who presented with amenorrhoea, a brain MRI is conducted to fully evaluate the tumour before surgical removal. The results reveal that the tumour is starting to compress the lateral geniculate nucleus of the thalamus.
What kind of symptom would arise from this compression?Your Answer: Visual impairment
Explanation:Visual impairment can occur as a result of damage to the lateral geniculate nucleus (LGN), which is a part of the thalamus involved in the visual pathway. The LGN receives information from the retina and sends it to the cortex via optic radiations. Although rare, the LGN can be damaged by compression from pituitary tumors or lesions affecting the choroidal arteries. However, damage to the LGN or other parts of the thalamus will not cause auditory impairment, aphasia, or reduced facial sensation. These conditions are typically caused by damage to other regions of the brain.
The Thalamus: Relay Station for Motor and Sensory Signals
The thalamus is a structure located between the midbrain and cerebral cortex that serves as a relay station for motor and sensory signals. Its main function is to transmit these signals to the cerebral cortex, which is responsible for processing and interpreting them. The thalamus is composed of different nuclei, each with a specific function. The lateral geniculate nucleus relays visual signals, while the medial geniculate nucleus transmits auditory signals. The medial portion of the ventral posterior nucleus (VML) is responsible for facial sensation, while the ventral anterior/lateral nuclei relay motor signals. Finally, the lateral portion of the ventral posterior nucleus is responsible for body sensation, including touch, pain, proprioception, pressure, and vibration. Overall, the thalamus plays a crucial role in the transmission of sensory and motor information to the brain, allowing us to perceive and interact with the world around us.
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This question is part of the following fields:
- Neurological System
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Question 10
Incorrect
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A different patient, presenting with symptoms of fatigue, polyuria and bone pains, is found to have a history of renal stones and depression. Blood tests reveal high serum calcium and parathyroid hormone levels, and low phosphate levels, leading to a suspected diagnosis of hyperparathyroidism. Imaging confirms the presence of a parathyroid adenoma, and the patient is started on treatment including a phosphate supplement for symptom relief. In this patient, where will the supplementary electrolyte primarily be reabsorbed?
Your Answer: Terminal ileum
Correct Answer: Proximal tubule
Explanation:The proximal tubule is responsible for the reabsorption of phosphate. This patient’s symptoms are consistent with hyperparathyroidism, which causes an increase in serum calcium levels and a decrease in phosphate levels due to increased osteoclast activity, increased renal and intestinal absorption of calcium, and reduced renal reabsorption of phosphate from the proximal tubule. Treatment for primary hyperparathyroidism typically involves a parathyroidectomy, but medical treatment can be used if surgery is not possible.
The distal tubules absorb electrolytes such as sodium, potassium, and calcium, and play a role in pH regulation through the absorption and secretion of bicarbonate and protons. However, only a minimal amount of phosphate is reabsorbed in the distal tubules.
The duodenum and jejunum are responsible for the absorption of iron and folate, respectively, but only a small amount of phosphate is reabsorbed in the gastrointestinal tract as a whole.
The loop of Henle reabsorbs several electrolytes, including sodium, potassium, chloride, magnesium, and calcium, but only a relatively small amount of phosphate is reabsorbed in this aspect of the renal tract.
The terminal ileum absorbs vitamin B12 and bile salts, but again, only a very small amount of phosphate is reabsorbed in the GI tract.
Maintaining Calcium Balance in the Body
Calcium ions are essential for various physiological processes in the body, and the largest store of calcium is found in the skeleton. The levels of calcium in the body are regulated by three hormones: parathyroid hormone (PTH), vitamin D, and calcitonin.
PTH increases calcium levels and decreases phosphate levels by increasing bone resorption and activating osteoclasts. It also stimulates osteoblasts to produce a protein signaling molecule that activates osteoclasts, leading to bone resorption. PTH increases renal tubular reabsorption of calcium and the synthesis of 1,25(OH)2D (active form of vitamin D) in the kidney, which increases bowel absorption of calcium. Additionally, PTH decreases renal phosphate reabsorption.
Vitamin D, specifically the active form 1,25-dihydroxycholecalciferol, increases plasma calcium and plasma phosphate levels. It increases renal tubular reabsorption and gut absorption of calcium, as well as osteoclastic activity. Vitamin D also increases renal phosphate reabsorption in the proximal tubule.
Calcitonin, secreted by C cells of the thyroid, inhibits osteoclast activity and renal tubular absorption of calcium.
Although growth hormone and thyroxine play a small role in calcium metabolism, the primary regulation of calcium levels in the body is through PTH, vitamin D, and calcitonin. Maintaining proper calcium balance is crucial for overall health and well-being.
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This question is part of the following fields:
- Neurological System
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Question 11
Correct
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A father brings his 14-year-old son into the Emergency Department, who he witnessed having a 'fit' 30 minutes ago. This occurred as his son was getting up from his chair. The father noticed some shaking of his son's arms, lasting approximately 10 minutes.
His son has been very stressed with school projects over the past week, staying up late and often missing meals. His son's past medical and developmental history is non-significant.
On examination, the son is alert and responsive.
What are the associated factors with this condition?Your Answer: Short postictal period
Explanation:The recovery from syncopal episodes is rapid and the postictal period is short. In contrast, seizures have a much longer postictal period. The stem suggests that the syncope may be due to exam stress and poor nutrition habits. One way to differentiate between seizures and syncope is by the length of the postictal period, with syncope having a quick recovery. Lip smacking is not associated with syncope, but rather with focal seizures of the temporal lobe. The 10-minute postictal period described in the stem is not consistent with a seizure.
Epilepsy is a neurological condition that causes recurrent seizures. In the UK, around 500,000 people have epilepsy, and two-thirds of them can control their seizures with antiepileptic medication. While epilepsy usually occurs in isolation, certain conditions like cerebral palsy, tuberous sclerosis, and mitochondrial diseases have an association with epilepsy. It’s important to note that seizures can also occur due to other reasons like infection, trauma, or metabolic disturbance.
Seizures can be classified into focal seizures, which start in a specific area of the brain, and generalised seizures, which involve networks on both sides of the brain. Patients who have had generalised seizures may experience biting their tongue or incontinence of urine. Following a seizure, patients typically have a postictal phase where they feel drowsy and tired for around 15 minutes.
Patients who have had their first seizure generally undergo an electroencephalogram (EEG) and neuroimaging (usually a MRI). Most neurologists start antiepileptics following a second epileptic seizure. Antiepileptics are one of the few drugs where it is recommended that we prescribe by brand, rather than generically, due to the risk of slightly different bioavailability resulting in a lowered seizure threshold.
Patients who drive, take other medications, wish to get pregnant, or take contraception need to consider the possible interactions of the antiepileptic medication. Some commonly used antiepileptics include sodium valproate, carbamazepine, lamotrigine, and phenytoin. In case of a seizure that doesn’t terminate after 5-10 minutes, medication like benzodiazepines may be administered to terminate the seizure. If a patient continues to fit despite such measures, they are said to have status epilepticus, which is a medical emergency requiring hospital treatment.
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This question is part of the following fields:
- Neurological System
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Question 12
Incorrect
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An 80-year-old man arrives at the emergency department accompanied by his wife. According to her, he has experienced sudden hearing loss and is currently unable to perceive any sounds. A stroke is suspected, and he is sent for an MRI scan which reveals a thalamic lesion.
Which specific nucleus of the thalamus is most likely affected by the lesion?Your Answer: Ventral posteromedial nucleus
Correct Answer: Medial geniculate nucleus
Explanation:Hearing impairment can result from damage to the medial geniculate nucleus of the thalamus, which is responsible for relaying auditory signals to the cerebral cortex. Similarly, damage to other regions of the thalamus can affect different types of sensory and motor functioning, such as visual loss from damage to the lateral geniculate nucleus, facial sensation from damage to the medial portion of the ventral posterior nucleus, and motor functioning from damage to the ventral anterior nucleus.
The Thalamus: Relay Station for Motor and Sensory Signals
The thalamus is a structure located between the midbrain and cerebral cortex that serves as a relay station for motor and sensory signals. Its main function is to transmit these signals to the cerebral cortex, which is responsible for processing and interpreting them. The thalamus is composed of different nuclei, each with a specific function. The lateral geniculate nucleus relays visual signals, while the medial geniculate nucleus transmits auditory signals. The medial portion of the ventral posterior nucleus (VML) is responsible for facial sensation, while the ventral anterior/lateral nuclei relay motor signals. Finally, the lateral portion of the ventral posterior nucleus is responsible for body sensation, including touch, pain, proprioception, pressure, and vibration. Overall, the thalamus plays a crucial role in the transmission of sensory and motor information to the brain, allowing us to perceive and interact with the world around us.
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This question is part of the following fields:
- Neurological System
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Question 13
Incorrect
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A 13-year-old girl is brought to the first-seizure clinic by her parents after experiencing multiple seizures in the past two weeks. According to her parents, the girl loses consciousness, becomes rigid, and falls to the ground while shaking for about two minutes during each episode. They also report that she has been experiencing urinary incontinence during these seizures.
The specialist decides to prescribe an antiepileptic medication.
What is the likely diagnosis for this patient, and what is the mechanism of action of the prescribed drug?Your Answer: Carbamazepine - partial antagonism of calcium channels
Correct Answer: Sodium valproate - inhibits sodium channels
Explanation:The patient in this scenario is experiencing a classic case of tonic-clonic seizures, which is characterized by unconsciousness, stiffness, and jerking of muscles. The first-line treatment for males with tonic-clonic seizures is sodium valproate, which is believed to work by inhibiting sodium channels and suppressing the excitation of neurons in the brain. Lamotrigine or levetiracetam is recommended for females due to the teratogenic effects of sodium valproate. Carbamazepine, which is a second-line treatment for focal seizures, would not be prescribed in this case. Ethosuximide, which is used to treat absence seizures, works by partially antagonizing calcium channels in the brain.
Treatment Options for Epilepsy
Epilepsy is a neurological disorder that affects millions of people worldwide. Treatment for epilepsy typically involves the use of antiepileptic drugs (AEDs) to control seizures. The decision to start AEDs is usually made after a second seizure, but there are certain circumstances where treatment may be initiated after the first seizure. These include the presence of a neurological deficit, structural abnormalities on brain imaging, unequivocal epileptic activity on EEG, or if the patient or their family considers the risk of having another seizure to be unacceptable.
It is important to note that there are specific drug treatments for different types of seizures. For generalized tonic-clonic seizures, males are typically prescribed sodium valproate, while females may be given lamotrigine or levetiracetam. For focal seizures, first-line treatment options include lamotrigine or levetiracetam, with carbamazepine, oxcarbazepine, or zonisamide used as second-line options. Ethosuximide is the first-line treatment for absence seizures, with sodium valproate or lamotrigine/levetiracetam used as second-line options. For myoclonic seizures, males are usually given sodium valproate, while females may be prescribed levetiracetam. Finally, for tonic or atonic seizures, males are typically given sodium valproate, while females may be prescribed lamotrigine.
It is important to work closely with a healthcare provider to determine the best treatment plan for each individual with epilepsy. Additionally, it is important to be aware of potential risks associated with certain AEDs, such as the use of sodium valproate during pregnancy, which has been linked to neurodevelopmental delays in children.
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This question is part of the following fields:
- Neurological System
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Question 14
Correct
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A 56-year-old male with a history of hypertension presents with symptoms of a stroke. Upon examination, he exhibits weakness on the right side of his face and arm, as well as expressive dysphasia. The diagnosis is confirmed, and thrombolysis is scheduled. Which artery is the most probable site of occlusion?
Your Answer: Left middle cerebral
Explanation:The patient is experiencing weakness and loss of sensation on the opposite side of their body, with the upper limb being more affected than the lower limb. They also have vision loss on the opposite side and difficulty with speech. These symptoms suggest that the middle cerebral artery on the left side of the brain is affected. It is important to have a good understanding of the circle of Willis and its cerebral associations to visualize the affected area. The left middle cerebral artery supplies the left temporal and parietal lobes of the brain, including the area responsible for speech, which explains the patient’s aphasia.
Stroke can affect different parts of the brain depending on which artery is affected. If the anterior cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the lower extremities being more affected than the upper. If the middle cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the upper extremities being more affected than the lower. They may also experience vision loss and difficulty with language. If the posterior cerebral artery is affected, the person may experience vision loss and difficulty recognizing objects.
Lacunar strokes are a type of stroke that are strongly associated with hypertension. They typically present with isolated weakness or loss of sensation on one side of the body, or weakness with difficulty coordinating movements. They often occur in the basal ganglia, thalamus, or internal capsule.
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This question is part of the following fields:
- Neurological System
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Question 15
Incorrect
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Sarah is a 30-year-old female who presents with a 3 day history of muscle weakness and pins and needles in both her feet which has now started to spread up into her legs. She reports having a stomach bug 3 weeks ago.
During examination, Sarah is apyrexial. There is reduced tone in both lower limbs with reduced knee jerk reflexes and altered sensation. Upper limb neurological examination is normal.
What is the probable diagnosis?Your Answer: Myasthenia gravis
Correct Answer: Guillain-Barré syndrome
Explanation:Stephen’s symptoms of progressive peripheral polyneuropathy and hyporeflexia strongly suggest Guillain-Barre syndrome, which may have been triggered by a recent gastrointestinal infection. Myasthenia gravis, on the other hand, typically presents with muscle fatigue and ocular manifestations, but normal tone, sensation, and reflexes. Polymyositis causes diffuse weakness in proximal muscles, while acute transverse myelitis results in paralysis of both legs, sensory loss, and bowel/bladder dysfunction, which are not present in Stephen’s case.
Guillain-Barre Syndrome: A Breakdown of its Features
Guillain-Barre syndrome is a condition that occurs when the immune system attacks the peripheral nervous system, resulting in demyelination. This is often triggered by an infection, with Campylobacter jejuni being a common culprit. In the initial stages of the illness, around 65% of patients experience back or leg pain. However, the characteristic feature of Guillain-Barre syndrome is progressive, symmetrical weakness of all limbs, with the legs being affected first in an ascending pattern. Reflexes are reduced or absent, and sensory symptoms tend to be mild. Other features may include a history of gastroenteritis, respiratory muscle weakness, cranial nerve involvement, diplopia, bilateral facial nerve palsy, oropharyngeal weakness, and autonomic involvement, which can lead to urinary retention and diarrhea. Less common findings may include papilloedema, which is thought to be secondary to reduced CSF resorption. To diagnose Guillain-Barre syndrome, a lumbar puncture may be performed, which can reveal a rise in protein with a normal white blood cell count (albuminocytologic dissociation) in 66% of cases. Nerve conduction studies may also be conducted, which can show decreased motor nerve conduction velocity due to demyelination, prolonged distal motor latency, and increased F wave latency.
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This question is part of the following fields:
- Neurological System
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Question 16
Incorrect
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A 65-year-old patient with a history of Parkinson's disease visits your clinic to discuss their medications. During their recent neurology appointment, they were advised to increase the dosage of one of their medications due to worsening symptoms, but they cannot recall which one. To aid their memory, you initiate a conversation about the medications and their effects on neurotransmitters. Which neurotransmitter is predominantly impacted in Parkinson's disease?
Your Answer: Gamma-aminobutyric acid (GABA)
Correct Answer: Dopamine
Explanation:Parkinson’s disease primarily affects dopaminergic neurons that project from the substantia nigra to the basal ganglia striatum. This is important to note as the condition is commonly treated with medications that increase dopamine levels, such as levodopa, dopamine agonists, and monoamine-oxidase-B inhibitors.
Serotonin is a neurotransmitter with a wide range of functions and is commonly used in medications such as antidepressants, antiemetics, and antipsychotics.
GABA primarily acts on inhibitory neurons and is important in the mechanism of drugs like benzodiazepines and barbiturates.
Acetylcholine is a neurotransmitter found at the neuromuscular junction and has roles within the central and autonomic nervous systems. It is important in conditions like myasthenia gravis and with drugs like atropine and neostigmine.
Noradrenaline is a catecholamine with various functions in the brain and activates the sympathetic nervous system outside of the brain. It is commonly used in anaesthetics and emergency situations and is an important mediator with drugs like beta-blockers.
Parkinson’s disease is a progressive neurodegenerative disorder that occurs due to the degeneration of dopaminergic neurons in the substantia nigra. This leads to a classic triad of symptoms, including bradykinesia, tremor, and rigidity, which are typically asymmetrical. The disease is more common in men and is usually diagnosed around the age of 65. Bradykinesia is characterized by a poverty of movement, shuffling steps, and difficulty initiating movement. Tremors are most noticeable at rest and typically occur in the thumb and index finger. Rigidity can be either lead pipe or cogwheel, and other features include mask-like facies, flexed posture, and drooling of saliva. Psychiatric features such as depression, dementia, and sleep disturbances may also occur. Diagnosis is usually clinical, but if there is difficulty differentiating between essential tremor and Parkinson’s disease, 123I‑FP‑CIT single photon emission computed tomography (SPECT) may be considered.
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This question is part of the following fields:
- Neurological System
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Question 17
Correct
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Which upper limb muscle is not supplied by the radial nerve?
Your Answer: Abductor digiti minimi
Explanation:The mnemonic for the muscles innervated by the radial nerve is BEST, which stands for Brachioradialis, Extensors, Supinator, and Triceps. On the other hand, the ulnar nerve innervates the Abductor Digiti Minimi muscle.
The Radial Nerve: Anatomy, Innervation, and Patterns of Damage
The radial nerve is a continuation of the posterior cord of the brachial plexus, with root values ranging from C5 to T1. It travels through the axilla, posterior to the axillary artery, and enters the arm between the brachial artery and the long head of triceps. From there, it spirals around the posterior surface of the humerus in the groove for the radial nerve before piercing the intermuscular septum and descending in front of the lateral epicondyle. At the lateral epicondyle, it divides into a superficial and deep terminal branch, with the deep branch crossing the supinator to become the posterior interosseous nerve.
The radial nerve innervates several muscles, including triceps, anconeus, brachioradialis, and extensor carpi radialis. The posterior interosseous branch innervates supinator, extensor carpi ulnaris, extensor digitorum, and other muscles. Denervation of these muscles can lead to weakness or paralysis, with effects ranging from minor effects on shoulder stability to loss of elbow extension and weakening of supination of prone hand and elbow flexion in mid prone position.
Damage to the radial nerve can result in wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals. Axillary damage can also cause paralysis of triceps. Understanding the anatomy, innervation, and patterns of damage of the radial nerve is important for diagnosing and treating conditions that affect this nerve.
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This question is part of the following fields:
- Neurological System
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Question 18
Incorrect
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A 25-year-old man is in a car accident and experiences initial wrist extension difficulty that gradually improves. What type of injury is probable?
Your Answer: Ulnar nerve neuropraxia
Correct Answer: Radial nerve neuropraxia
Explanation:Neuropraxia is the most probable injury due to the transient loss of function. The radial nerve innervates the wrist extensors, indicating that this area is the most likely site of damage.
Neuropraxia: A Temporary Nerve Injury with Full Recovery
Neuropraxia is a type of nerve injury where the nerve remains intact but its electrical conduction is affected. However, the myelin sheath that surrounds the nerve remains intact, which means that the nerve can still transmit signals. The good news is that neuropraxia is a temporary condition, and full recovery is expected. Additionally, autonomic function is preserved, which means that the body’s automatic functions such as breathing and heart rate are not affected. Unlike other types of nerve injuries, Wallerian degeneration, which is the degeneration of the nerve fibers, does not occur in neuropraxia. Overall, neuropraxia is a relatively minor nerve injury that does not cause permanent damage and can be expected to fully heal.
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This question is part of the following fields:
- Neurological System
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Question 19
Incorrect
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A 72-year-old male comes to the emergency department with sudden onset left sided hemiparesis and speech difficulties. There is no sensory loss. During the examination, you observe weakness in the left upper limb. Although she nods to indicate understanding, her responses are slow and difficult. You suspect a stroke.
What is the most probable location of the lesion in the brain?Your Answer: Primary motor cortex
Correct Answer: Inferior frontal gyrus
Explanation:Broca’s aphasia is caused by a lesion in the inferior frontal gyrus, leading to non-fluent and laboured speech. On the other hand, Wernicke’s aphasia is caused by a lesion in the superior frontal gyrus, resulting in fluent but nonsensical speech. The arcuate fasciculus connects these two areas, and a lesion in this connection can cause fluent speech with poor repetition. A lesion in the primary motor cortex causes contralateral motor deficits, while a lesion in the cerebellum results in slurred speech, horizontal nystagmus, intention tremors, and an ataxic gait.
Types of Aphasia: Understanding the Different Forms of Language Impairment
Aphasia is a language disorder that affects a person’s ability to communicate effectively. There are different types of aphasia, each with its own set of symptoms and underlying causes. Wernicke’s aphasia, also known as receptive aphasia, is caused by a lesion in the superior temporal gyrus. This area is responsible for forming speech before sending it to Broca’s area. People with Wernicke’s aphasia may speak fluently, but their sentences often make no sense, and they may use word substitutions and neologisms. Comprehension is impaired.
Broca’s aphasia, also known as expressive aphasia, is caused by a lesion in the inferior frontal gyrus. This area is responsible for speech production. People with Broca’s aphasia may speak in a non-fluent, labored, and halting manner. Repetition is impaired, but comprehension is normal.
Conduction aphasia is caused by a stroke affecting the arcuate fasciculus, the connection between Wernicke’s and Broca’s area. People with conduction aphasia may speak fluently, but their repetition is poor. They are aware of the errors they are making, but comprehension is normal.
Global aphasia is caused by a large lesion affecting all three areas mentioned above, resulting in severe expressive and receptive aphasia. People with global aphasia may still be able to communicate using gestures. Understanding the different types of aphasia is important for proper diagnosis and treatment.
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This question is part of the following fields:
- Neurological System
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Question 20
Incorrect
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A 32-year-old man is given morphine after an appendicectomy and subsequently experiences constipation. What is the most likely explanation for this occurrence?
Your Answer: Inhibition of DOPA receptors
Correct Answer: Stimulation of µ receptors
Explanation:Morphine treatment often leads to constipation, which is a prevalent side effect. This is due to the activation of µ receptors.
Morphine is a potent painkiller that belongs to the opiate class of drugs. It works by binding to the four types of opioid receptors in the central nervous system and gastrointestinal tract, resulting in its therapeutic effects. However, it can also cause unwanted side effects such as nausea, constipation, respiratory depression, and addiction if used for a prolonged period.
Morphine can be taken orally or injected intravenously, and its effects can be reversed with naloxone. Despite its effectiveness in managing pain, it is important to use morphine with caution and under the guidance of a healthcare professional to minimize the risk of adverse effects.
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This question is part of the following fields:
- Neurological System
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Question 21
Incorrect
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A 22-year-old man is stabbed in the antecubital fossa and requires surgical exploration of the wound. During the operation, the surgeon dissects down onto the brachial artery and identifies a nerve medially. Which nerve is most likely to be identified?
Your Answer: Ulnar
Correct Answer: Median
Explanation:Anatomy and Function of the Median Nerve
The median nerve is a nerve that originates from the lateral and medial cords of the brachial plexus. It descends lateral to the brachial artery and passes deep to the bicipital aponeurosis and the median cubital vein at the elbow. The nerve then passes between the two heads of the pronator teres muscle and runs on the deep surface of flexor digitorum superficialis. Near the wrist, it becomes superficial between the tendons of flexor digitorum superficialis and flexor carpi radialis, passing deep to the flexor retinaculum to enter the palm.
The median nerve has several branches that supply the upper arm, forearm, and hand. These branches include the pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor pollicis longus, and palmar cutaneous branch. The nerve also provides motor supply to the lateral two lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis muscles, as well as sensory supply to the palmar aspect of the lateral 2 ½ fingers.
Damage to the median nerve can occur at the wrist or elbow, resulting in various symptoms such as paralysis and wasting of thenar eminence muscles, weakness of wrist flexion, and sensory loss to the palmar aspect of the fingers. Additionally, damage to the anterior interosseous nerve, a branch of the median nerve, can result in loss of pronation of the forearm and weakness of long flexors of the thumb and index finger. Understanding the anatomy and function of the median nerve is important in diagnosing and treating conditions that affect this nerve.
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This question is part of the following fields:
- Neurological System
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Question 22
Correct
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A 78-year-old man comes to the emergency department complaining of double vision. According to his wife, he fell in the garden earlier today and hit his head on a bench. During the examination, you notice that his left eye is fixed in a down and out position. After performing a CT scan, you discover that he has an extradural hematoma on the left side. These types of hematomas are often caused by the middle meningeal artery rupturing. Which foramina does this artery use to enter the cranium?
Your Answer: Foramen spinosum
Explanation:The correct answer is the foramen spinosum, which is a small opening in the cranial cavity that allows the meningeal artery to pass through.
The foramen lacerum is covered with cartilage during life and is sometimes described as the passage for the nerve and artery of the pterygoid canal. However, it is more accurate to say that they pass into the cartilage that blocks the foramen before entering the pterygoid canal, which is located in the anterior wall of the foramen.
The foramen ovale is an oval-shaped opening that allows the mandibular nerve to pass through.
The foramen magnum is the largest of the foramen and is located in the posterior of the cranial cavity. It allows the brainstem and associated structures to pass through.
Foramina of the Base of the Skull
The base of the skull contains several openings called foramina, which allow for the passage of nerves, blood vessels, and other structures. The foramen ovale, located in the sphenoid bone, contains the mandibular nerve, otic ganglion, accessory meningeal artery, and emissary veins. The foramen spinosum, also in the sphenoid bone, contains the middle meningeal artery and meningeal branch of the mandibular nerve. The foramen rotundum, also in the sphenoid bone, contains the maxillary nerve.
The foramen lacerum, located in the sphenoid bone, is initially occluded by a cartilaginous plug and contains the internal carotid artery, nerve and artery of the pterygoid canal, and the base of the medial pterygoid plate. The jugular foramen, located in the temporal bone, contains the inferior petrosal sinus, glossopharyngeal, vagus, and accessory nerves, sigmoid sinus, and meningeal branches from the occipital and ascending pharyngeal arteries.
The foramen magnum, located in the occipital bone, contains the anterior and posterior spinal arteries, vertebral arteries, and medulla oblongata. The stylomastoid foramen, located in the temporal bone, contains the stylomastoid artery and facial nerve. Finally, the superior orbital fissure, located in the sphenoid bone, contains the oculomotor nerve, recurrent meningeal artery, trochlear nerve, lacrimal, frontal, and nasociliary branches of the ophthalmic nerve, and abducent nerve.
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This question is part of the following fields:
- Neurological System
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Question 23
Correct
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An 80-year-old man is recuperating after undergoing a right total hip replacement. During a session with the physiotherapists, it is observed that his right foot is dragging on the ground while walking.
Upon conducting a neurological examination of his lower limbs, it is found that his left leg is completely normal. However, his right leg has 0/5 power of dorsiflexion and knee flexion, a reduced ankle and plantar reflex, and no sensation over the lateral calf, sole, and dorsum of the foot.
What is the nerve lesion that has occurred?Your Answer: Sciatic nerve
Explanation:Foot drop can be caused by a lesion to the sciatic nerve.
When the sciatic nerve is damaged, it can result in various symptoms such as foot drop, loss of power below the knee, loss of knee flexion, loss of ankle jerk and plantar response. The sciatic nerve innervates the hamstring muscles in the posterior thigh and indirectly innervates other muscles via its two terminal branches: the tibial nerve and the common fibular nerve. The tibial nerve supplies the calf muscles and some intrinsic muscles of the foot, while the common fibular nerve supplies the muscles of the anterior and lateral leg, as well as the remaining intrinsic foot muscles. Although the sciatic nerve has no direct sensory inputs, it receives information from its two terminal branches, which supply the skin of various areas of the leg and foot.
Sciatic nerve lesions can occur due to various reasons, such as neck of femur fractures and total hip replacement trauma. However, it is important to note that a femoral nerve lesion would cause different symptoms, such as weakness in anterior thigh muscles, reduced hip flexion and knee extension, and loss of sensation to the anteromedial thigh and medial leg and foot. Similarly, lesions to the lower gluteal nerve or superior gluteal nerve would cause weakness in specific muscles and no sensory loss.
Understanding Foot Drop: Causes and Examination
Foot drop is a condition that occurs when the foot dorsiflexors become weak. This can be caused by various factors, including a common peroneal nerve lesion, L5 radiculopathy, sciatic nerve lesion, superficial or deep peroneal nerve lesion, or central nerve lesions. However, the most common cause is a common peroneal nerve lesion, which is often due to compression at the neck of the fibula. This can be triggered by certain positions, prolonged confinement, recent weight loss, Baker’s cysts, or plaster casts to the lower leg.
To diagnose foot drop, a thorough examination is necessary. If the patient has an isolated peroneal neuropathy, there will be weakness of foot dorsiflexion and eversion, and reflexes will be normal. Weakness of hip abduction is suggestive of an L5 radiculopathy. Bilateral symptoms, fasciculations, or other abnormal neurological findings are indications for specialist referral.
If foot drop is diagnosed, conservative management is appropriate. Patients should avoid leg crossing, squatting, and kneeling. Symptoms typically improve over 2-3 months.
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This question is part of the following fields:
- Neurological System
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Question 24
Correct
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A 40-year-old woman with Down's syndrome visits her doctor accompanied by her caregiver. The doctor is informed that the woman's memory has been declining and it is now affecting her daily activities. Upon hearing their concerns, the doctor explains that individuals with Down's syndrome have a higher likelihood of developing a specific type of dementia compared to the general population.
What type of dementia is more common among individuals with Down's syndrome?Your Answer: Alzheimer's disease
Explanation:Trisomy 21, also known as Down’s syndrome, is associated with an increased risk of developing Alzheimer’s disease. This is because the amyloid precursor protein gene (APP) is located on chromosome 21, and individuals with trisomy 21 have three copies of this gene. APP is believed to play a significant role in the development of Alzheimer’s disease, and almost all people with Down’s syndrome will have amyloid plaques in their brain tissue by the age of 40. While there have been some case studies linking Down’s syndrome to other forms of dementia, such as dementia with Lewy bodies and frontotemporal dementia, the relationship is not as well established as it is with Alzheimer’s disease. There is no known association between Down’s syndrome and normal pressure hydrocephalus or vascular dementia.
Alzheimer’s disease is a type of dementia that gradually worsens over time and is caused by the degeneration of the brain. There are several risk factors associated with Alzheimer’s disease, including increasing age, family history, and certain genetic mutations. The disease is also more common in individuals of Caucasian ethnicity and those with Down’s syndrome.
The pathological changes associated with Alzheimer’s disease include widespread cerebral atrophy, particularly in the cortex and hippocampus. Microscopically, there are cortical plaques caused by the deposition of type A-Beta-amyloid protein and intraneuronal neurofibrillary tangles caused by abnormal aggregation of the tau protein. The hyperphosphorylation of the tau protein has been linked to Alzheimer’s disease. Additionally, there is a deficit of acetylcholine due to damage to an ascending forebrain projection.
Neurofibrillary tangles are a hallmark of Alzheimer’s disease and are partly made from a protein called tau. Tau is a protein that interacts with tubulin to stabilize microtubules and promote tubulin assembly into microtubules. In Alzheimer’s disease, tau proteins are excessively phosphorylated, impairing their function.
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This question is part of the following fields:
- Neurological System
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Question 25
Incorrect
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A 58-year-old man, previously diagnosed with small cell lung cancer, visits his GP complaining of a recent onset headache, nausea, and vomiting that have been worsening over the past week. He reports feeling dizzy when the headache starts and an unusual increase in appetite, resulting in weight gain. Despite his history of little appetite due to his lung cancer, he has been insatiable lately. Which part of the hypothalamus is likely affected by the metastasis of his lung cancer, causing these symptoms?
Your Answer: Lateral nucleus
Correct Answer: Ventromedial nucleus
Explanation:The ventromedial nucleus of the hypothalamus is responsible for regulating satiety, and therefore, damage to this area can result in hyperphagia.
The posterior nucleus plays a role in stimulating the sympathetic nervous system and body heat, and lesions in this area can lead to autonomic dysfunction and poikilothermia.
The lateral nucleus is responsible for stimulating appetite, and damage to this area can cause a decrease in appetite and anorexia.
The paraventricular nucleus produces oxytocin and ADH, and lesions in this area can result in diabetes insipidus.
The dorsomedial nucleus is responsible for stimulating aggressive behavior and can lead to savage behavior if damaged.
The hypothalamus is a part of the brain that plays a crucial role in maintaining the body’s internal balance, or homeostasis. It is located in the diencephalon and is responsible for regulating various bodily functions. The hypothalamus is composed of several nuclei, each with its own specific function. The anterior nucleus, for example, is involved in cooling the body by stimulating the parasympathetic nervous system. The lateral nucleus, on the other hand, is responsible for stimulating appetite, while lesions in this area can lead to anorexia. The posterior nucleus is involved in heating the body and stimulating the sympathetic nervous system, and damage to this area can result in poikilothermia. Other nuclei include the septal nucleus, which regulates sexual desire, the suprachiasmatic nucleus, which regulates circadian rhythm, and the ventromedial nucleus, which is responsible for satiety. Lesions in the paraventricular nucleus can lead to diabetes insipidus, while lesions in the dorsomedial nucleus can result in savage behavior.
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This question is part of the following fields:
- Neurological System
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Question 26
Incorrect
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During a challenging femoro-popliteal bypass surgery, the surgeon mistakenly applies a clamp on the femoral nerve. The clamp remains in place for a significant portion of the procedure. Upon examination after the operation, the nerve is found to be intact but shows signs of compression. What is the most probable outcome in the coming months?
Your Answer: Rapid restoration of neuronal function because the axon itself is intact
Correct Answer: Wallerian degeneration
Explanation:Despite the nerve remaining intact, a neuronal injury can lead to Wallerian degeneration and potentially the formation of neuromas.
Nerve injuries can be classified into three types: neuropraxia, axonotmesis, and neurotmesis. Neuropraxia occurs when the nerve is intact but its electrical conduction is affected. However, full recovery is possible, and autonomic function is preserved. Wallerian degeneration, which is the degeneration of axons distal to the site of injury, does not occur. Axonotmesis, on the other hand, happens when the axon is damaged, but the myelin sheath is preserved, and the connective tissue framework is not affected. Wallerian degeneration occurs in this type of injury. Lastly, neurotmesis is the most severe type of nerve injury, where there is a disruption of the axon, myelin sheath, and surrounding connective tissue. Wallerian degeneration also occurs in this type of injury.
Wallerian degeneration typically begins 24-36 hours following the injury. Axons are excitable before degeneration occurs, and the myelin sheath degenerates and is phagocytosed by tissue macrophages. Neuronal repair may only occur physiologically where nerves are in direct contact. However, nerve regeneration may be hampered when a large defect is present, and it may not occur at all or result in the formation of a neuroma. If nerve regrowth occurs, it typically happens at a rate of 1mm per day.
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This question is part of the following fields:
- Neurological System
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Question 27
Incorrect
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A 72-year-old male presents to the emergency department with severe, central abdominal pain that is radiating to his back. He has vomited twice and on examination you find he has hypotension and tachycardia. He is a current smoker with a past medical history of hypertension and hypercholesterolaemia. You suspect a visceral artery aneurysm and urgently request a CT scan to confirm. The CT scan reveals an aneurysm in the superior mesenteric artery.
From which level of the vertebrae does this artery originate from the aorta?Your Answer: L5
Correct Answer: L1
Explanation:The common iliac veins come together at
Anatomical Planes and Levels in the Human Body
The human body can be divided into different planes and levels to aid in anatomical study and medical procedures. One such plane is the transpyloric plane, which runs horizontally through the body of L1 and intersects with various organs such as the pylorus of the stomach, left kidney hilum, and duodenojejunal flexure. Another way to identify planes is by using common level landmarks, such as the inferior mesenteric artery at L3 or the formation of the IVC at L5.
In addition to planes and levels, there are also diaphragm apertures located at specific levels in the body. These include the vena cava at T8, the esophagus at T10, and the aortic hiatus at T12. By understanding these planes, levels, and apertures, medical professionals can better navigate the human body during procedures and accurately diagnose and treat various conditions.
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This question is part of the following fields:
- Neurological System
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Question 28
Correct
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A 45-year-old man is brought to the ED by his spouse, who suspects he had a stroke. The man is exhibiting signs of slurred speech and disorientation to time and space, but there is no limb weakness.
According to collateral history, the man has a history of epilepsy, although he has not had a seizure in several months. He does not smoke and did not consume any alcohol or drugs before coming to the ED. A CT scan is normal, and a focal seizure is suspected as the cause of his symptoms.
Which part of the brain is likely affected?Your Answer: Temporal lobe
Explanation:Localising features of a temporal lobe seizure include postictal dysphasia and lip smacking.
Localising Features of Focal Seizures in Epilepsy
Focal seizures in epilepsy can be localised based on the specific location of the brain where they occur. Temporal lobe seizures are common and may occur with or without impairment of consciousness or awareness. Most patients experience an aura, which is typically a rising epigastric sensation, along with psychic or experiential phenomena such as déjà vu or jamais vu. Less commonly, hallucinations may occur, such as auditory, gustatory, or olfactory hallucinations. These seizures typically last around one minute and are often accompanied by automatisms, such as lip smacking, grabbing, or plucking.
On the other hand, frontal lobe seizures are characterised by motor symptoms such as head or leg movements, posturing, postictal weakness, and Jacksonian march. Parietal lobe seizures, on the other hand, are sensory in nature and may cause paraesthesia. Finally, occipital lobe seizures may cause visual symptoms such as floaters or flashes. By identifying the specific location and type of seizure, doctors can better diagnose and treat epilepsy in patients.
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This question is part of the following fields:
- Neurological System
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Question 29
Correct
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A neurologist is consulted for a patient who has displayed limited visual fields in one eye during an examination. Upon conducting an MRI, the neurologist discovers a tumor in the right temporal lobe, near the border with the occipital region. What type of visual impairment is the patient most likely experiencing?
Your Answer: Left superior homonymous quadrantanopia
Explanation:Temporal lobe lesions result in contralateral homonymous quadrantanopias, with damage to the Meyer’s loop and optic radiations causing this condition. The optic radiations receiving information from the superior quadrants are located more inferiorly while those from the inferior travel more superiorly. As the lesion is located in the lower part of the right temporal lobe near the occipital region, it is likely to affect the left superior quadrant. It is important to note that lesions on the temporal lobe correspond to superior quadrants rather than inferior, and damage to the right side of the brain affects the left visual field. Additionally, temporal lobe lesions cause quadrantanopias and not hemianopias.
Understanding Visual Field Defects
Visual field defects can occur due to various reasons, including lesions in the optic tract, optic radiation, or occipital cortex. A left homonymous hemianopia indicates a visual field defect to the left, which is caused by a lesion in the right optic tract. On the other hand, homonymous quadrantanopias can be categorized into PITS (Parietal-Inferior, Temporal-Superior) and can be caused by lesions in the inferior or superior optic radiations in the temporal or parietal lobes.
When it comes to congruous and incongruous defects, the former refers to complete or symmetrical visual field loss, while the latter indicates incomplete or asymmetric visual field loss. Incongruous defects are caused by optic tract lesions, while congruous defects are caused by optic radiation or occipital cortex lesions. In cases where there is macula sparing, it is indicative of a lesion in the occipital cortex.
Bitemporal hemianopia, on the other hand, is caused by a lesion in the optic chiasm. The type of defect can indicate the location of the compression, with an upper quadrant defect being more common in inferior chiasmal compression, such as a pituitary tumor, and a lower quadrant defect being more common in superior chiasmal compression, such as a craniopharyngioma.
Understanding visual field defects is crucial in diagnosing and treating various neurological conditions. By identifying the type and location of the defect, healthcare professionals can provide appropriate interventions to improve the patient’s quality of life.
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This question is part of the following fields:
- Neurological System
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Question 30
Incorrect
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A 63-year-old woman presents to the GP clinic with complaints of neck discomfort. During the neurological examination, the doctor observes numbness in the thumb. Which dermatome is associated with this symptom?
Your Answer: T1
Correct Answer: C6
Explanation:The index finger and thumb are the primary locations of the C6 dermatome.
Understanding Dermatomes: Major Landmarks and Mnemonics
Dermatomes are areas of skin that are innervated by a single spinal nerve. Understanding dermatomes is important in diagnosing and treating various neurological conditions. The major dermatome landmarks are listed in the table above, along with helpful mnemonics to aid in memorization.
Starting at the top of the body, the C2 dermatome covers the posterior half of the skull, resembling a cap. Moving down to C3, it covers the area of a high turtleneck shirt, while C4 covers the area of a low-collar shirt. The C5 dermatome runs along the ventral axial line of the upper limb, while C6 covers the thumb and index finger. To remember this, make a 6 with your left hand by touching the tip of your thumb and index finger together.
Moving down to the middle finger and palm of the hand, the C7 dermatome is located here, while the C8 dermatome covers the ring and little finger. The T4 dermatome is located at the nipples, while T5 covers the inframammary fold. The T6 dermatome is located at the xiphoid process, and T10 covers the umbilicus. To remember this, think of BellybuT-TEN.
The L1 dermatome covers the inguinal ligament, while L4 covers the knee caps. To remember this, think of being Down on aLL fours with the number 4 representing the knee caps. The L5 dermatome covers the big toe and dorsum of the foot (except the lateral aspect), while the S1 dermatome covers the lateral foot and small toe. To remember this, think of S1 as the smallest one. Finally, the S2 and S3 dermatomes cover the genitalia.
Understanding dermatomes and their landmarks can aid in diagnosing and treating various neurological conditions. The mnemonics provided can help in memorizing these important landmarks.
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This question is part of the following fields:
- Neurological System
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