Section 6 Flashcards

Question

A 6-year-old child is brought with a history of sudden onset loss of consciousness following a headache that had been present for the past 5 days. On examination, the Glasgow Coma Scale score is E2V2M5. He undergoes an emergency CT scan of the brain, which shows obstructive hydrocephalus with a mass in the pineal region. He undergoes an emergency ventriculostomy of the third ventricle. The cerebrospinal fluid turns to be positive for placental alkaline phosphatase. What is the probable diagnosis? 1. Germinoma 2. Choriocarcinoma 3. Endodermal sinus tumor 4. Teratoma

Answer 1

**1. Germinoma** ## Footnote * The patient has a pineal region tumor with obstructive hydrocephalus, which is causing the drop in the Glasgow Coma Scale score. * Since the CSF is positive for placental alkaline phosphatase (PLAP), the most probable diagnosis is a germinoma. * PLAP can also be positive in the serum of the patient. * Beta-human chorionic gonadotropin is positive in choriocarcinoma.

Answer 2

**4. Prior baseline neuropsychological testing demonstrating a low score** ## Footnote * A patient who has suffered a brain injury may complain of a headache, nausea, memory loss, dizziness, blurry vision, confusion, fatigue, photophobia or phonophobia, motor or sensory loss, poor hand-eye coordination, irritability, or depression. Patients with these symptoms should be prohibited from participating in activities and immediately evaluated. * The Glasgow coma scale is a validated tool for rapidly assessing a person's level of consciousness. It has three components: eye-opening, verbal response, and motor response. Points are assigned based on the patient's response. The best score is 15, and anything less than eight is considered severe head injury/coma. This athlete scored in the mild category with a score of 14 to 15. The tool is not validated to predict the risk for a second impact syndrome and should not be used to allow an athlete to participate once a concussion has been suspected or diagnosed. * Neuropsychologic testing should be performed both initially and during follow-up evaluation of a patient with a history of concussion. However, the early baseline reading that is often performed on athletes to have a standard for comparison with a low score does not warrant prohibition from participation in activities and sports. Some athletes may try and get an initial low score, so when they repeat the test and get a low score, it will be close to their baseline. * Due to the increased fragility of the brain following an initial head injury, only a minimal amount of force is required on a subsequent incident to result in irreparable damage. Therefore, a high index of suspicion for second injury syndrome is warranted for all patients with a known history of head injury. Athletes with a head injury should not be allowed to return to participation until completing an approved return to play protocol.

Answer 3

**3. FGFR3** ## Footnote * Crouzon syndrome is characterized by facial deformations at or near birth. * The physical findings include a wide face secondary to the obliteration of the coronal and sagittal sutures. * Findings include hypertelorism, wide and high forehead, malocclusion, short stature, and the absence of physiologic spinal curvature. * Acanthosis nigricans of the axillary fossa is seen in those with FGFR3 mutations.

Answer 4

**3. Altered cerebral autoregulation** ## Footnote * In chronic hypertensive patients, there is a rightward shift of the cerebral blood flow autoregulatory curve. * The lower limit of the autoregulation curve is increased thereby a sudden drop in blood pressure can lead to diminished cerebral blood flow thereby resulting in ischemia. * It is therefore recommended to maintain the systolic blood pressure of these patients at around 130mm Hg. This minimizes the risk of rebleed as well as protects from the effects of hypotension. * Intracranial pressure can not increase without an increase in the size of the hematoma in the CT images. Patients with seizures will have visible abnormal body movements and the uprolling of eyes and frothing from the mouth, which was absent in this patient.

Answer 5

**2. The anterior choroidal artery** ## Footnote * The white matter structure situated in the inferomedial part of each cerebral hemisphere of the brain is the internal capsule. * The inferior part of the posterior limb of the internal capsule is supplied by the perforating branches anterior choroidal artery. * The superior levels of the anterior limb, genu, and posterior limb get their supply from perforating arteries of the middle cerebral artery. * The inferior levels of the anterior limb obtain their blood supply by the Heubner artery and perforating arteries of the anterior cerebral artery and the inferior levels of the genu get supplied by perforating arteries of the internal carotid artery and proximal perforating arteries of the anterior choroidal artery.

Answer 6

**2. Choroid plexus obstruction** ## Footnote * The length of the catheter is cut as estimated according to preoperative imaging (roughly 5-5.5 cm when measured at the inner table of the calvarium) and attached to the base of the reservoir with a silk tie. This length allows the tip of the catheter to be positioned on the floor of the anterior horn of the lateral ventricle. * A longer intraventricular catheter, as in this patient, is often associated with obstruction due to the choroid plexus at the foramen of Monroe. * The correct placement of the catheter can be verified with an image guidance system. * The distal end of the intraventricular catheter does not usually get obstructed by septum pellucidum as it can not occlude its orifices or by the membrane of Liliequist, which is outside the ventricles. An infection will not occlude a catheter unless the patient has significant debris from the ventriculitis. Mechanical failure is very uncommon with modern Ommaya reservoirs.

Answer 7

**1. Dysplastic** ## Footnote * Dysplastic spondylolisthesis is of a congenital origin and affects children. * Isthmic spondylolisthesis is caused by a defect in the pars interarticularis and is most common in those in their second decade and older. * Degenerative spondylolisthesis typically affects older individuals. * Traumatic spondylolisthesis occurs after high impact injuries such as hyperflexion with compression or axial rotation in a motor vehicle collision.

Answer 8

**2. Continue with therapy followed by repeat imaging in 6-8 weeks.** ## Footnote * Continuing with therapy followed by repeat imaging in 2 months is recommended as the imaging finding is likely a treatment- related effect called pseudoprogression. Pseuoprogression is usually asymptomatic, which is the case in this scenario. * Pseudoprogression is a phenomenon that is usually seen four to six weeks after the completion of chemoradiotherapy. * Pseudoprogression is a treatment-related effect with imaging findings similar to tumor progression. It usually occurs within three months of completion of chemoradiation in glioblastoma patients. * Distinguishing between pseudoprogression due to treatment and true progression of the disease is important to avoid inappropriate discontinuation of treatment in patients.

Answer 9

**2. Vertebral artery Injury** ## Footnote * C2 transarticular screw represents a multiple level instrumentation option. The screw is applied at a trajectory 0 to 15 degrees medial from the starting point at the inferomedial angle of C2-C3 facet. * However, this procedure provides the highest rate of possible vertebral artery injury. * Detailed CT scan evaluation of the anatomy of C1 needs to be obtained before any surgical intervention to identify any abnormal course or anomaly of the vertebral artery (e.g., high riding vertebral artery) before such arthrodesis. * Vertebral artery injury on one side should preclude the surgeon from the insertion of a similar screw contralaterally, as bilateral vertebral artery injury can lead to devastating brain stem stroke

Answer 10

**1. Magnetic resonance imaging of the cervical spine** ## Footnote * The patient describes a clinical case of occipital headaches with neck pain with a history of whiplash injury to the neck. This is typical of cervicogenic headaches. * Even though the diagnosis of cervicogenic headaches is clinical, magnetic resonance imaging (MRI) cervical spine should be ordered to identify the source of pathology in the C-spine such as disc herniation, degenerative disc disease, etc. * MRI cervical spine is necessary to identify the accurate level of pathology in the c-spine for possible interventional therapy, including interventional procedures/surgery. * The patient's symptoms are not consistent with a migraine, so naproxen is unnecessary. MRI brain with contrast would offer no additional diagnostic advantages for the patient in a setting of cervicogenic headaches. Lumbar puncture is not indicated for the diagnosis of cervicogenic headaches.

Answer 11

**2. Primary central nervous system lymphoma** ## Footnote * Central nervous system lymphoma is seen in up to 6% of patients with AIDs and is the second most common mass lesion of the central nervous system in the AIDs population. Immunocompromised individuals can present with single or multiple lesions. * Presentation is often related to the location of the lesion. Occipital lobe lesions usually result in visual field defects. Seizures are more commonly seen in AIDs related central nervous system lymphomas. * The Epstein-Barr virus is associated with 100% of AIDs related central nervous system lymphomas. Magnetic resonance imaging is the best initial test used in diagnosis. In immunosuppressed individuals, enhancement is often irregular or rim-like due to the presence of central necrosis. Stereotactic brain biopsy is the gold standard for diagnosis. * Diffuse large B cell lymphoma is the most common histological variant seen. High-dose methotrexate has demonstrated efficacy in the treatment of AIDs related central nervous system lymphoma.

Answer 12

**2. Rostral interstitial nucleus of medial longitudinal fasciculus and interstitial nucleus of Cajal** ## Footnote * Tumors of the pineal region cause Parinaud syndrome due to compression of the upper brainstem (midbrain). * This syndrome includes; paralysis of upwards gaze, pupils with light-near dissociation, convergence-retraction nystagmus, eyelid retraction, and conjugate down-gaze. * Paralysis of the upwards gaze and conjugate down-ward gaze is caused by compression of the vertical gaze center at the rostral interstitial nucleus of medial longitudinal fasciculus. * Light-near dissociation is caused by the compression of the pretectal nucleus. Convergence-retraction nystagmus and eye- lid retraction (collier’s sign) is caused by damage to the supranuclear fibers of the third nerve at the posterior midbrain.

Answer 13

**4. Pulmonary embolus** ## Footnote * A documented potential complication of vertebroplasty and kyphoplasty is pulmonary embolus. * Overzealous injection of polymethyl methacrylate (PMMA) cement can lead to particles entering the vertebral venous plexus leading to eventual embolization to the lungs. * Vertebroplasty and kyphoplasty are done under direct, fluoroscopic visualization to avoid extra-vertebral cement administration. * Other potential complications include infection, spinal hematoma, and nerve damage. Antibiotic prophylaxis, coagulation panels, and fluoroscopy help to minimize the risk of complications.

Answer 14

**1. Renal ultrasound** ## Footnote * When multiple members of the family are affected with cerebral aneurysms, it should raise the suspicion of autosomal polycystic kidney disease. * The incidence of aneurysms in these cohorts of patients is approximately 11%. Though the incidence is comparable to the general population, these patients have a high risk of developing progressive renal cysts as well. * The prime defect is the mutation in the PKD1 and PKD2 genes. This leads to the formation of multiple cysts within various organs such as the liver and kidney. It also predisposes to the formation of multiple intracranial aneurysms. * Other syndromes associated with multiple intracranial aneurysms include Marfan syndrome, hypereosinophilic syndrome and Diamond-Blackfan syndrome.

Answer 15

**3. Intubate and ventilate the patient with a target paCO2 of 4.5 to 5.0 kPa** ## Footnote * The priority next step in the management of the patient is to secure the airway with intubation. There is level III evidence that patients with TBI and a GCS of 8 or less should be intubated. * Avoidance of hypoxia and control of paCO2 is vital. There is level III evidence that O2 saturations 90% in TBI significantly raise mortality. The target paCO2 of 4.5 to 5 kPa is ideal. * An ABC approach is vital in trauma patients (airway, breathing, circulation). After securing the airway and ventilating the patient, a target MAP of 60 to 70 mmHg is recommended with level III evidence to reduce mortality in TBI. * The administration of osmotic therapy in TBI is indicated in an acutely deteriorating patient with signs of herniation. It would be appropriate to administer mannitol to this patient while obtaining a CT scan, but securing the airway and ventilating is the first priority. Blind placement of an EVD without CT imaging in this patient would not be appropriate.

Answer 16

**2. Magnetic resonance angiography of cerebral vessels** ## Footnote * Behcet disease is an auto-inflammatory systemic vasculitis of unknown etiology and is characterized by mucocutaneous manifestations including recurrent oral and genital ulcerations, ocular manifestations especially chronic relapsing uveitis and systemic vasculitis involving arteries and veins of all sizes. * This patient appears to have features suggestive of posterior communicating artery aneurysm. The involvement of vasa vasorum (vasculitis) may result in the formation of aneurysms in the arteries. * Venular involvement and formation of pulmonary and arterial aneurysms are unique to Behcet disease. * The most helpful test in the diagnosis of cerebral aneurysms is contrast angiography. Management of aneurysms that have already bled is endovascular coiling or surgical clipping.

Answer 17

**2. Injury to bridging veins due to CSF over-drainage** ## Footnote * CSF over-drainage is a common complication following CSF diversion procedures like lumbar drain insertion. * CSF over-drainage leads to sagging of the brain parenchyma which can lead to injury to bridging veins and result in subdural hematoma. * If a patient presents with acute deterioration of GCS and evidence of herniation (pupillary dilation), urgent evacuation of subdural hematoma should be performed. * Controlled CSF drainage and preventing intracranial hypotension is very important following any CSF diversion procedure.

Answer 18

**1. Spinal cord decompression** ## Footnote * Given the patient's history of kyphoscoliosis and osteoporosis, her complaints of decreased mobility, lower extremity weakness, and loss of sensation are likely due to spinal cord compromise secondary to progression of spinal defects. Compression of the spinal cord can lead to devastating complications such as paraparesis or paraplegia and warrants referral for surgical evaluation. * Operative management may be indicated in those patients who have failed conservative therapy, experience intractable pain, or have an onset of neurologic changes. * Neurologic manifestations can include changes in strength, sensation, reflexes, or bowel/bladder control. * Given the patient's history of osteoporosis and worsening back pain with neurological signs, an epidural steroid injection is contraindicated.

Answer 19

**1. Corticosteroids** ## Footnote * Corticosteroids are the mainstay of treatment for neurosarcoidosis. The majority of patients with sarcoidosis do not have symptoms. Neurosarcoidosis may be life-threatening and tends to occur in cases with systemic involvement. * Symptoms of neurosarcoidosis may be multifocal, commonly seen first in the cranial nerves. The facial nerve is the most common cranial nerve affected, which may mimic Lyme disease. Psychiatric and cognitive symptoms may occur in patients with diffuse meningeal inflammation associated with neurosarcoidosis. * MRI findings of meningeal enhancement may translate to seizures in a clinical setting. An F-18 fluorodeoxyglucose positron emission tomography (PET) scan can be helpful in identifying areas with active granulomatous inflammation. * In cases of a meningeal, parenchymal mass lesion or myopathy or neuropathy, prednisone should be given for at least 4 weeks. For deteriorating patients, intravenous (IV) methylprednisolone is given for 3 days followed by prednisone for 2 to 4 weeks.

Answer 20

**3. Naming common items that are visually introduced** ## Footnote * Agnosia is the inability to recognize familiar items visually, so presenting the items and asking the patient to name them would be the best screen. * The deficit cannot be explained by memory, attention, language problems, or unfamiliarity with the stimuli. * Visual agnosia refers to an impairment in recognizing visually presented objects, despite otherwise normal visual field, acuity, color vision, brightness discrimination, language, and memory. * Apperceptive visual agnosia is an abnormality in visual perception and discriminative process, despite the absence of elementary visual deficits. Apperceptive visual agnosia is typically associated with lesions to the parietal and occipital cortex.

Answer 21

**2. No change in latency** ## Footnote * Latency is a measure of the speed of the fastest muscle fibers. There is no change in latency in cervical radiculopathy. * As with sensory nerve conduction studies, the sensory and motor nerve conduction study will be normal in cervical radiculopathy. Latency and amplitude are usually normal. * These normal findings occur because only a fraction of nerve fascicles within the nerve root are affected. However, axon loss ensues if there is sufficient root compression where distal parts of axons are not continuous with the cell body. * Amplitude is a measure of the magnitude of muscle force. It is unchanged in typical cervical radiculopathy. However, spontaneous activity of the paraspinal muscles is often seen on EMG within the first five to seven days.

Answer 22

**2. Obtaining cervical CT and measuring the lateral overhang of the lateral masses of C1 on C2** ## Footnote * Changes in bladder and bowel function can be caused by cervical spine instability. * 10% to 30% of patients with Down syndrome have atlantoaxial instability with or without subluxation, but estimates vary. * Early symptoms may be challenging to get from the patients and may need to be inferred by refusing to participate in usual activities. Any change in motor skills or progressive paralysis should cause consideration of this diagnosis. * Although overflow incontinency might occur in those patients with mental retardation, which might respond to bowel management schedules, the newly onset encopresis without any previous history in the mentioned patient is unlikely.

Answer 23

**3. 1 g/kg over 30 minutes intravenously** ## Footnote * The dosing of mannitol to decrease intracranial pressure is 0.25 to 2 g/kg intravenous. * Mannitol should never be given subcutaneous or intramuscular. * Mannitol is typically given over 30 to 60 minutes. * It should be ensured patient has a response to mannitol with increased urine output.

Answer 24

**2. Expectant management only.** ## Footnote * The pathophysiology of spinal injury involves two stages - a. primary injury, which happens directly at the time of trauma; and b. secondary injury happening due to necro-inflammatory responses leading to cell death, tissue degeneration, the formation of a glial scar, axonal degeneration, and demyelination.a * Various pharmacological agents have been tried in the past to reduce the inflammatory responses causing secondary spinal injury. Over the past 30 years ago, methylprednisolone was believed to decrease lipid peroxidation-triggered secondary damage following spinal cord injury. * National Acute Spinal Cord Injury Studies II (NASCIS II) study recommended 30 mg/kg bolus dose of methylprednisolone sodium succinate on admission, followed by infusion at the rate of 5.4 mg/kg/h for the next 23 h in patients presenting less than 3 hours and infusion at the rate of 5.4 mg/kg/h for the next 48 h in patients presenting less than 8 hours. * However, no other randomized controlled studies could validate these findings of the NASCIS II trial. It is no longer recommended in the American Association of Neurological Surgeons (AANS) guidelines for the management of acute spinal cord injuries.

Answer 25

**4. Holoprosencephaly** ## Footnote * This fetus likely has trisomy 13, or Patau syndrome. Patau syndrome is a chromosomal abnormality in which affected fetuses have an extra copy of chromosome 13. * Most patients with Patau syndrome will die in utero, so the diagnosis is usually made during autopsy. Of the affected infants that are born alive, the median survival is seven days. * Patau syndrome presents with severe intellectual disability, cleft lip/palate, holoprosencephaly, polydactyly, cutis aplasia, and congenital heart disease. * Holoprosencephaly is a disorder in which the forebrain of the fetus fails to separate into a left and right hemisphere. In mild to moderate cases, a cleft lip or palate may occur. In severe cases, affected patients can be born with cyclopia. Cyclopia is when both eyes are fused into a single midline structure.

Answer 26

**1. Computed tomography (CT) scan head without intravenous contrast** ## Footnote * Computed tomography (CT) of the brain is the most commonly employed imaging test in the emergent setting for patients with new-onset seizures. It is the preferred test in the emergency setting, given the speed at which it can be obtained. CT is used to rule out life-threatening pathologies such as intracranial hemorrhage or stroke but plays a limited role in the evaluation of seizures. It is reasonable to pursue a CT brain initially in this patient, given her right upper extremity weakness, which could be due to Todd paralysis or stroke. A non-contrast CT should be obtained as a first screen for either of these pathologies while a patient is in the emergency room. * Contrast-enhanced CT can demonstrate regions of abnormal enhancement within the brain but is less sensitive than MRI, and seldomly performed. CT angiography may be used to rule out vascular lesions such as aneurysm, dissection, and vasculitis, but these abnormalities rarely present with seizures. * Following CT imaging of the brain, if no acute abnormalities are discovered, an MRI should be obtained on a non-emergent basis. A late-life first-onset seizure is usually a sign of malignancy or stroke, as epilepsy is a disease that presents in childhood and early adulthood. * A brain MRI can be used to evaluate nearly any anatomic cause of seizures, but are typically not performed on an emergent basis. CT with contrast makes it difficult to visualize any obvious bleed. EEG is useful to evaluate for seizures, but this patient requires an urgent CT to evaluate for brain trauma.

Answer 27

**3. This decreases the blood supply from small scalp veins.** ## Footnote * In a brain death study, there would not be any actual cerebral blood flow on the nuclear medicine perfusion test (NMPT). * One should not inadvertently confuse scalp veins with cerebral vessels and get a false negative study. * The elastic band minimizes scalp blood flow. * The apnea test remains the gold standard for final confirmation of brain death. NMPT is an ancillary test.

Answer 28

**1. Antiplatelet therapy** ## Footnote * The goal of therapy is to prevent clot formation or treat clot formation. It is the thrombosis that causes stroke by clot embolization, not the dissection itself. * Start either antiplatelet and anticoagulant therapy once the diagnosis is made and no contraindications exist. * Supportive care is indicated in this patient but needs to be done in conjunction with antiplatelet and or anticoagulant therapy. * Thrombolytic therapy is a treatment option in patients with neurologic deficits presenting within 4.5 hours if they have no contraindications. This patient, however, presented 12 hours after the symptom onset. Surgical repair in this patient's situation is not indicated. Most dissections heal spontaneously. The treatment is not aimed at the dissection but for thrombotic prevention. Surgery is reserved for those with recurrent dissections.

Answer 29

**1. A characteristic “ice-cream cone appearance"** ## Footnote * Acoustic neuroma produces the characteristic “ice-cream cone" appearance on contrast-enhanced imaging. * The signs and symptoms of acoustic neuroma are attributed to the involvement of the cranial nerve VIII, compressing surrounding cranial nerves, cerebellum, and brainstem. * The majority of acoustic neuromas present with unilateral hearing loss due to cochlear nerve interruption or impairment of blood supply to the nerve. Other clinical features include tinnitus, decreased word understanding, vertigo, headaches, and facial numbness. * Up to 70% to 90% of tumors in the cerebellopontine angle are acoustic neuromas.

Answer 30

**1. Medial branch of the posterior ramus** ## Footnote * The sign and symptoms in this patient are suggestive of facet arthritis. A medial branch block of the posterior ramus is diagnostic for facet arthritis. * The injection of corticosteroids or a local anesthetic into the facet joint is both diagnostic and therapeutic. * Some anesthetists suggest injecting corticosteroids at the site where the medial branch of the spinal nerve enters the bone. Fluoroscopy should be used to identify the notch between the superior articulating surface and the transverse process. * Great care should be taken not inject inside the vertebral artery or the radicular branches that enter the neural foramina.

Answer 31

**1. ONSD of 6.2 mm pre-therapy and 4.8 mm post-therapy** ## Footnote * As with most diagnostic imaging, trends and repeat evaluation are far more suggestive than a single number. An ONSD of 6.8 mm is extremely elevated, and a reduction to 4.8 mm would suggest decreasing ICP. * The ONSD changes in real-time based on ICP, and interventions to lower ICP can be monitored by serial exams. * Performing serial ONSUS is the only available modality in the described scenario. The US Army CPGs suggest an initial bolus of 250 ccs of 3% hypertonic saline followed by 50-100 mL/hr with target sodium of 150 to 160 mEq/L. * Conservative measures for improving cerebral perfusion include increasing systolic blood pressure (>110 mmHg) and elevation of the head of the bed to 30 to 45 degrees.

Answer 32

**2. Pituitary microadenoma** ## Footnote * Cushing disease is reserved for Cushing syndrome that is caused by excessive secretion of adrenocorticotropic hormone (ACTH) from a pituitary tumor, usually an adenoma. * Cushing disease is responsible for 70% of cases of endogenous Cushing syndrome. The rest of the cases are caused by ectopic secretion of ACTH by a tumor. * The pituitary tumors in Cushing disease are microadenomas, which measure 10 mm or less. These microadenomas do not cause mass effect and are often discovered after hypersecretion of ACTH is determined. * Macroadenomas are uncommon in patients with Cushing disease. These tumors cause mass effects such as suprasellar extension, optic chiasm compression, and cavernous sinus compression.

Answer 33

**1. Internal carotid artery** ## Footnote * The patient in the question is experiencing a right-sided hemiparesis, sudden onset severe headache, ptosis (drooping of the left eyelid), miosis (1mm constriction of the left pupil), and transient monocular blindness (loss of vision in the left eye that has now returned. This is consistent with the internal carotid artery (ICA) dissection. * The risk factors for ICA dissection (and vertebral artery dissection) include sports trauma and minor trauma that can be experienced with chiropractic manipulation. Other factors which can increase the risk factor for ICA dissection include Ehlers- Danlos syndrome, fibromuscular dysplasia, and Marfan syndrome (all of which fall under connective tissue diseases). The connective tissue disorders make the layers of the blood vessel weaker and more prone to injury with lower trauma. * Patients with ICA dissections will primarily experience stroke- like or (TIA) Transient ischemia attack-like symptoms, though a number of patients will be asymptomatic. Those who are symptomatic can have hemiparesis, TIA which also includes transient monocular blindness, and Horner syndrome. Horner syndrome occurs because the sympathetic fibers of the superior cervical ganglion partly travel with the internal carotid artery. Dissection of the ICA can lead to distention of these fibers and cause Horner syndrome. In this case, anhidrosis was not seen but miosis and ptosis were. * ICA dissection and vertebral artery dissection are mostly similar and have similar clinical presentations as well as the same risk factors. The common carotid artery gives off no branches beyond the two terminal branches, ICA, and ECA. The external carotid artery provides blood supply to many structures in the face, neck, and skull but is generally not thought to supply the brain parenchyma whereas the ICA does not have many branches until intracranial at which point it gives off the Middle cerebral artery and anterior cerebral artery.

Answer 34

**1. Mycobacterium tuberculosis** ## Footnote * Tuberculous meningitis (TBM) is a manifestation of extrapulmonary tuberculosis caused by the seeding of the meninges with the bacilli of Mycobacterium tuberculosis (MTB). * Tuberculous meningitis presents 1% of all cases of extra- pulmonary TB. In the developed world where there is a lower prevalence of TB in the population, estimates are that TBM accounts for 6% of all causes of meningitis. * In locations with a higher prevalence of MTB in the population, estimates are that TBM accounts for up to one third to one half of all bacterial meningitis. * Tuberculous meningitis assessment is by obtaining cerebrospinal fluid (CSF) for analysis. Typically, the CSF reveals low glucose, elevated protein, and modestly elevated WBC count with a lymphocytic predominance. The CSF analysis most closely resembles the CSF analysis of viral meningitis.

Answer 35

**3. Continue with cervical orthosis until it is determined if planned surgical intervention is needed** ## Footnote * She has most likely C1 vertebral fracture. These are an indication for definitive treatment with halo vest immobilization (HVI); however, severe soft tissue disruptions over the proposed pin sites are absolute contraindications. This patient has severe soft tissue disruption over where the anterior pins would be placed. Therefore this is contraindicated in this patient. * Immobilization is necessary when a trauma patient presents with a tender cervical spine. Furthermore, CT imaging confirms a cervical spine fracture; therefore, it is required to continue with cervical immobilization with a cervical orthosis. * This patient has an upper cervical spine fracture. Definitive treatment requires immobilization, which can be achieved with either surgical intervention or rigid external immobilization via the halo vest immobilizer. Halo vest immobilization (HVI) is contraindicated in this patient; therefore, surgical immobilization is the most appropriate treatment plan for this patient if indicated. Since the patient has an unstable cervical spine injury, they need to maintain a cervical collar until the planned procedure. * Surgery is an appropriate option, and HVI can be placed for temporary postoperative adjuvant immobilization in these injuries; however, this patient has an absolute contraindication because of severe soft tissue disruption where the anterior pin has to be placed. Therefore this is incorrect.

Answer 36

**3. During the late teenage years the to early 20s when the slippage is 25%** ## Footnote * Spondylolysis is a problem from the late teenage years to the early 20s. A positive stork test that is single leg hyperextension and rotation of the spine, which reproduces the patient pain, is diagnostic of spondylolysis until proven otherwise. * It becomes symptomatic when there is at least 25% slippage. * Some patients have no risk factors, but recurrent lumbar hyperextension does predispose people to this condition. * Conservative treatment usually suffices, but if cord compromise occurs, surgery is necessary.

Answer 37

**1. Disconnection or malfunction of the interconnection of neurons** ## Footnote * Diffuse axonal injury (DAI) is a disruption of the cytoskeleton of the axonal portion of a neuron. There is damage or disruption of the interconnection of neurons. * This is commonly caused by traumatic acceleration and deceleration injury. DAI is a clinical diagnosis. Typically, DAI is considered in patients with a Glasgow coma scale (GCS) of less than 8 for over six hours. * A head CT has a low yield in detecting diffuse axonal injury related injuries, but severe forms may show small punctate hemorrhages to white matter tracts. Currently, magnetic resonance imaging (MRI), specifically diffuse tensor imaging (DTI), is the imaging modality of choice for the diagnosis of diffuse axonal injury. * Concussion causes biochemically induced neuronal dysfunction. In cytotoxic cerebral edema, there is a disturbance of cellular metabolism and accumulation of intracellular water. In hypoxia, the neurons are damaged due to intracellular energy failure and lead to cell death.

Answer 38

**3. Intravenous desmopressin** ## Footnote * Diabetes insipidus is a common complication following pituitary surgery. Diabetes insipidus (DI) is a disease process that results in either decreased release of or response to antidiuretic hormone (ADH, also known as vasopressin or AVP), which can cause electrolyte imbalances. * Most cases of diabetes insipidus following transsphenoidal hypophysectomy are transient. About 20% of patients who undergo neurosurgery will present with diabetes insipidus * Treatment is with fluid replacement and desmopressin. The most common findings in patients with diabetes insipidus are polydipsia, polyuria, and nocturia. IV D5W can be used for IV fluid replacement, but IV desmopressin is the better choice. The other choices are not effective for diabetes insipidus. * Risk factors for developing diabetes insipidus due to transsphenoidal hypophysectomy include craniopharyngioma or extensive intraoperative handling of the pituitary gland

Answer 39

**4. Amphotericin B** ## Footnote * This patient likely has a disease of infectious etiology involving his lungs and brain. The presentation, along with his occupation and biopsy findings, makes the likely diagnosis to be disseminated blastomycosis. The recommended treatment for moderate to severe blastomycosis is amphotericin B. * Amphotericin B is a broad-spectrum antifungal that exerts its fungicidal action by binding to ergosterol, a key component of fungal cell membranes. It is the recommended treatment for life- threatening blastomycosis and also in those with CNS disease. It has an extensive side effect profile and can cause renal dysfunction, hypokalemia, anemia, and thrombophlebitis, which can limit its use. * The recommended treatment dose of amphotericin in blastomycosis is 0.7 to 1 mg per day to a total dose of 1.5 to 2 gm. It has been seen that higher total doses are associated with a decreased frequency of relapse. * The liposomal formulation of amphotericin B is associated with less toxicity and is preferred where available. Oral itraconazole has poor CNS penetration and is avoided in severe disease. Voriconazole may be an alternative to amphotericin B. Sulphadiazine-pyrimethamine is recommended in toxoplasmosis, whereas antituberculous therapy is effective in treating tuberculosis.

Answer 40

**2. Cervical provocation discography** ## Footnote * The most important adjunct in the evaluation of cervical discogenic pain syndrome is cervical provocation discography. * Cervical provocation discography is an image-guided procedure where a contrast agent is injected into the nucleus pulposus of the suspected intervertebral disc. The study includes disc stimulation and morphological assessment; it not only identifies painful cervical intervertebral disc, but it can depict internal derangements as well. * In cervical discogenic pain syndrome, radiographic findings may be normal. It may show degenerative changes, but there is little correlation with symptomatic vs. asymptomatic individuals based solely on these findings. * Dynamic MRI cervical spine is indicated in suspected cases of Hirayama disease. MRI is contraindicated in patients with a cardiac pacemaker.

Answer 41

**2. MRI easily demonstrates subacute thrombus** ## Footnote * MRI has difficulty showing acute thrombosis because of the presence of deoxyhemoglobin. This makes the thrombus isointense on T1 and hypointense on T2, indistinguishable from normal flow void. * Clot appears bright on both T1 and T2 MRI of subacute thrombus. * TOF MRV is poor in subacute situations because the normal T1 hyperintensity falsely simulates normal flow of a patent sinus. * Contrast-enhanced MRV is poor in chronic situations because chronic thrombus can enhance secondary to organizing fibrosis, and thus falsely simulate normal flow of a patent sinus.

Answer 42

**1. Antibiotics and Tdap (tetanus, diphtheria, pertussis) immunization** ## Footnote * This patient has an open frontal sinus fracture requiring antibiotics, and a tetanus toxoid shot since the patient has not received a booster within the last ten years. Amoxicillin with clavulanic acid is the initial antibiotic of choice if there is no intracranial extension of the injury. If there is a displaced posterior table fracture, a third-generation cephalosporin should be administered for coverage across the blood-brain barrier. * The sinuses are considered sterile under normal conditions, but the introduction of debris and skin flora is possible after such an injury and requires the appropriate systemic antibiotics coverage. Coverage for both Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) should be considered in these patients. * This condition, if untreated, could lead to complications like meningitis, frontal sinusitis, or osteomyelitis. * In the case of a frontal sinus fracture, appropriate antibiotic coverage is needed, and a Tdap booster is also required to cover for Clostridium tetani, which can lead to respiratory distress and death. The wound should be decontaminated, followed by closure; however, this is not sufficient to prevent local infection and possibly tetanus. Neurosurgery consultation may be indicated depending on the underlying injuries; however, based on the initial assessment of this patient, a computed tomography scan of the head and facial bones should be obtained prior to the consultation.

Answer 43

**1. High levels of plasma adrenocorticotropic hormone** ## Footnote * Risk factors for developing Nelson syndrome have been studied with means of achieving early detection and treatment. High levels of plasma adrenocorticotropic hormone following bilateral adrenalectomy have the strongest predictive capabilities. * Most of the Nelson syndrome cases are seen as a result of bilateral adrenalectomy for the treatment of Cushing disease. * It is hypothesized that the loss of feedback inhibition of the hypothalamic-pituitary-adrenal axis leads to the development of an adrenocorticotropic hormone-secreting pituitary tumor. * Age and sex have not been significantly associated with increased risk; however, younger patients undergoing bilateral adrenalectomy have a higher lifetime risk of developing Nelson syndrome.

Answer 44

**4. TLICS Score of 8; Posterior surgical decompression and stabilization** ## Footnote * This patient's Thoracolumbar Injury Classification System (TLICS) score adds to 8, (morphology = 1 + 1 for burst fracture = 2, incomplete spinal cord injury = 3, posterior ligament complex injury/tear = 3). The most appropriate treatment would be surgical decompression from the burst fracture through a posterior approach and stabilization. Stabilization is warranted due to the tearing of the PLC with anterior stabilization. This correlates to a 3 column injury, and the spine is inherently unstable. * Thoracolumbar Injury Classification System (TLICS) categorizes injury by morphology (compression, burst, translation/rotation, distraction), posterior ligamentous complex integrity (intact, indeterminate, disrupted) and neurological status (intact, complete, incomplete, cauda equina). The TLICS scoring is a tool used during thoracolumbar trauma and can guide treatment. Scores of 5 or greater are recommended for surgery. * The TLICS score is unique in that it places a significant emphasis on the integrity of the PLC. The PLC consists of the supraspinous ligament, interspinous ligament, ligamentum flavum, and facet joint capsules. Disruption of the PLC is typically indicated by widening of the interspinous space or of the facet joints, empty facet joints, facet perch or subluxation, and dislocation of the spine. MRI is the best imaging study to examine the integrity of the PLC and is indicated for any burst fracture or spinal column fracture with neurologic deficits to determine the extent of soft tissue injury and neurologic injury. * Bracing, steroids, or bedrest would be improper management due to the patient's abnormal neurologic exam and extent of injury seen on CT and MRI. Time to the operation room and decompression/stabilization will give this patient the best chance for recovery and to decrease morbidity.

Answer 45

**3. Pedicle violation** ## Footnote * The pedicle screw fixation is the most common method of the spinal fixation since it incorporates all the three Denis columns of the spine thereby maximizing its stability. * The pedicle screw placement in the children is, however, challenging owing to its anatomical variability compared to their adult counterparts. The pedicles are of smaller width, and the spinal canal is comparatively narrower. * There is a high risk of pedicle violations during the procedure. The estimated risk of either the medial or the lateral violation of the pedicle screw in the pediatric population is approximately 16% in the postoperative CT images. * The incidence of vascular injury and the nonunion following the implant fixation in pediatric patients are minimal compared to that of the risk of screw malpositions.

Answer 46

**1. Assessment of the outer annulus not seen on MRI** ## Footnote * A main point of discography is a real-time evaluation of the internal morphology of the disk and CT axial scanning for outer annular tears that are of clinical significance. This is of value in planning intradiscal treatments such as PRP, regenerative agent injections, intradiscal thermal treatments, and/or endoscopic diskectomy. * Discography may have a role in surgical planning but is just one part of a workup that is done within the context of clinical exam, history, comparison to other imaging studies, usually also with an EMG. Grossly abnormal grade 5 disks leaking opening anteriorly and posteriorly may potentially be painless despite being unstable and appropriate for fusion. * Discography has nothing to do with SIJ and facet-mediated pain. She may have some degree of SIJ pain independent of the discogenic pain. Something simple as altered gait mechanics may cause SIJ pain and or dysfunction. * Endplate-driven changes are not differentiated from annular- driven changes but may be apparent even on the fluoro images at the time of the discogram. Type 1 vs 2 Modic endplate changes are differentiated on MRI.

Answer 47

**2. Cranial MRI with contrast** ## Footnote * Millard-Gubler syndrome (MGS) is one of the classical crossed brainstem syndromes characterized by a unilateral lesion of the basal part of the caudal pons. * The 6th and 7th cranial nerves and the corticospinal tract are involved in this syndrome. * MRI of the brain is more sensitive and specific than CT scan to small pontine lesions. Also, in a patient with multiple sclerosis (MS), MRI with contrast can delineate between new and old lesions. * Causes of MGS include tumors, infections, MS, and vascular- related lesions.

Answer 48

**1. MRI in the first 24-72 hours** ## Footnote * This patient has brain cancer. In 20-40 years of age, low-grade gliomas are common. * MRI defines low-grade glioma (LGG) features and surgery is the recommended treatment in LGG. * Postoperatively, to plan a subsequent therapy, MRI is performed in the first 24-72 hours. Observation is recommended to detect any neurologic deficits afterward. * Postoperative evaluation is required in brain tumors, and MRI is the best modality. CT, PET, and biopsy can help in diagnosis but are not required for follow-up of brain tumors.

Answer 49

**4. Anteroposterior diameter of the lumbar spinal canal 10 mm** ## Footnote * The average diameter of a lumbar spinal cord is usually greater than or equal to 15 mm. * When there is a diameter noted to be less than 12 mm, this is considered significant for spinal stenosis. * The average diameter of a cervical spinal cord is usually greater than or equal to 13 mm. When there is a diameter noted to be less than 10 mm, this is considered significant for cervical spinal stenosis. * Anything less than 12 mm is considered significant for spinal stenosis. This would best fit the patient described in the question stem. Statin-induced myopathy and peripheral neuropathy should also be in the differential diagnosis, along with vascular claudication.

Answer 50

**4. 14-21 days after injury** ## Footnote * EMG is most useful 2 to 3-weeks after the injury as the involved muscles had undergone denervation. EMG is done every six weeks. Stimulation of the nerve below the lesion will result in a compound muscle action potential (CMAP) wave from the neurapraxic axons. * Needle EMG is the most sensitive study. The motor response amplitude decrement begins around days 2–3 and is complete by day 6. After a 2- to a 3-week interval, the involved muscles undergo denervation, and EMG is indicated. * After a 2 to 3-week interval, when small-amplitude, if short- duration (SASD) motor unit potentials are detected in the EMG, the prognosis for recovery is excellent. * In a complete neurapraxia lesion, no motor unit action potentials (MUAPs) are elicited under voluntary control. EMG can differentiate if the cause of weakness is neuropathic or myopathic. In neurapraxic lesions, the muscle does not reveal any abnormal spontaneous activity (fibrillation and positive sharp waves). On follow-up, the presence of MUAPs indicates that reinnervation is taking place.

Answer 51

**4. Offer posterior laminectomy, costotransversectomy, bilateral pediculotomy with posterolateral corpectomy with adjuvant posterior pedicle screw fixation** ## Footnote * Given the patient's significant disability and that he was functional otherwise with good oncologic prognosis, surgery must be considered. * Surgery is much preferred over radiation therapy alone as he already has significant cord impingement with weakness to his lower extremities. Direct surgical debulking is preferred. Adjuvant postoperative radiation may be considered in most cases, but surgery is the mainstay here. * Only offer surgeries that you feel comfortable performing, and your hospital can accommodate. Lateral approaches to the thoracic spine are viable options, but if there is no thoracic surgery on standby, it will put the patient at extra risk in case of complications. * In addition, posterior pedicle subtraction with corpectomy through a costotransversectomy provides excellent visualization and access to both sides of the vertebra, which a lateral approach does not afford so easily. Posterior fusion will need to be supplemented with T8 graft placement.

Answer 52

**3. MRI brain** ## Footnote * The patient has sensorineural hearing loss with cerebellar signs that suggest lesion originating in the internal auditory meatus and compressing upon the cerebellum. * Acoustic neuroma that grows into the cerebellopontine cisterns typically presents with such signs and symptoms. * MRI brain allows for better stratification of the management plan and grading of such lesions. With newer techniques such as tractography and constructive interference steady state (CISS), MRI also helps in forming surgical strategy in safe excision of the lesion after safeguarding facial nerve. * Otoscopy and CT temporal bone help in the assessment of patients with conductive pattern hearing loss. PTA only helps in determining the pattern and severity of hearing loss.

Answer 53

**4. Prefrontal cortex** ## Footnote * The prefrontal cortex is involved in short-term memory. * It must cooperate with other parts of the cortex as it extracts information for brief periods. * Short-term memory has a limited capacity. * Transfer of information to long-term memory is needed for more permanent storage.

Answer 54

**3. Smith-Petersen osteotomy** ## Footnote * A Smith-Petersen osteotomy is indicated in cases of mild- moderate sagittal imbalances. * Smith-Petersen osteotomies provide up to 10 degrees of correction per level of the osteotomy. * No anterior fusion is required when performing a Smith- Petersen osteotomy. * Pedicle subtraction osteotomies and vertebral column resection are indicated in cases of severe sagittal imbalance and provide much more correction than a Smith-Petersen osteotomy. Salter osteotomies of the pelvic are pediatric procedures used in the setting of dysplastic hips.

Answer 55

**3. Syphilis** ## Footnote * Argyll-Robertson pupils is highly specific for late-stage neurosyphilis. * Argyll-Robertson pupils are irregular miotic pupils. There is no pupillary light response, but there is brisk pupillary constriction to near stimuli. Dilatation in the dark is poor. * The anterior visual pathway function is normal. It is most commonly caused by a lesion in the region of the Sylvian aqueduct in the rostral midbrain. * This interferes with supranuclear inhibitory fibers and fibers for light reflex close to the Edinger-Westphal nuclei.

Answer 56

**2. Ibuprofen** ## Footnote * Lumbosacral plexopathy can be a transient disorder, as in the case of pregnancy. * Symptoms most often occur between 32-34 weeks gestation. * Postpartum lumbosacral plexus symptoms arise due to birth trauma and direct compression caused by the fetal head at the pelvic brim. * The majority of patients have a complete resolution of their symptoms two to six months following delivery.

Answer 57

**4. Magnetic resonance imaging (MRI) with the administration of intravenous gadolinium** ## Footnote * Discitis is an infection of the intervertebral disc space. The role of the intervertebral discs is to separate and cushion the spinal segments from each other. An infection, and thus inflammation of these discs can cause much pain and discomfort. MRI is the best test for this patient. * MRI is the most sensitive and specific test for diagnosis. * MRI will help the physician diagnose discitis at an early stage and also helps diagnose other causes of back pain (eg, herniated intervertebral disk, spinal stenosis). * Treatment options range from immediate broad-spectrum antibiotics to awaiting cultures for sensitivity before administering antibiotics, to spinal bracing alone without antibiotics.

Answer 58

**3. Symptomatic control only** ## Footnote * Human T cell lymphotropic virus 1 (HTLV-1) infection causes HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). * HAM/TSP usually presents with lower limb weakness and spasticity. * There is a high risk of developing HAM/TSP following solid organ transplant from an infected donor. * Though steroids and interferon have been trialed and are used, there is very limited evidence to support their effectiveness. Symptomatic treatment is the first-line.

Answer 59

**2. Systemic staging** ## Footnote * Systemic staging is warranted prior to treatment because 4% to 12% of patients thought to have primary central nervous system lymphoma are found with systemic disease. * Primary central nervous system lymphoma comprises 5% of all primary brain tumors and 1% of non-Hodgkin lymphomas. The most common subtype is the diffuse large B cell variant. * Magnetic resonance imaging often shows hypointense lesions on T1, that are hyperintense on T2 with restricted diffusion on diffusion-weighted imaging. Post-contrast enhancement is typical. Up to 60% of lesions are solitary in immunocompetent individuals, while 30% to 80% of immunosuppressed patients present with multiple lesions. * Males are more frequently affected than females in immunocompetent individuals as well as in patients with AIDS. Lesions have a predilection for the periventricular white matter, as well as the frontal lobe and basal ganglia.

Answer 60

**4. Latency period prior to obliteration of the arteriovenous malformation** ## Footnote * Stereotactic radiosurgery can be considered for arteriovenous malformations (AVMs) with a nidus smaller than 3 cm and often is considered for deeply located AVMs. * Potential advantages of radiosurgery include the ability to be performed as an outpatient, non-invasiveness, and lack of recovery period. * There is a latency period of 1 to 3 years between the time that stereotactic radiosurgery is performed and the AVM is actually obliterated. * During the latency period after stereotactic radiosurgery, the risk of hemorrhage from an AVM persists.

Answer 61

**2. Urgent spinal decompression and fusion of his thoracolumbar spine within 24-48 hours** ## Footnote * Traumatic Lumbar Locked Facets are rare injuries that occur most commonly with high energy mechanisms in the workplace or in motor vehicle collisions in men aged 35-55. * Locked Facet Syndrome requires spinal decompression and fusion. * In the setting of a complete spinal cord injury, decompression should occur in the first 24-48 hours. However, there is no need for emergent decompression in a complete spinal cord injury. * Fusion is necessary after lumbar spinal decompression. IV Steroid use has not shown substantial benefit in spinal cord injuries and leads to more complications. Observation is not appropriate in the setting of Traumatic Locked Facets.

Answer 62

**3. The intactness of spinolaminar line** ## Footnote * The large head size of small children can cause a typical picture of pseudosubluxation at the C2-3 level on plain lateral radiographs, which may be mistaken for an underlying injury. Lateral radiographs in young children may be obtained by placing the children on a spine board with a recess for the head, so as to negate this disproportion between the child's head and body. * Scischuk observed C2-3 pseudosubluxation as a normal variant on lateral cervical radiographs. He defined the posterior cervical (C1-3 spinolaminar) line as a reference to distinguish it from Hangman's fracture. * Harrison observed this pseudo-subluxation phenomenon even in children aged between 14 and 18 years. In their series involving pediatric polytrauma patients, 21.7% presented with pseudo-subluxation. * In these scenarios, it may be difficult to differentiate between true and pseudo-subluxations. In physiological subluxation, Swischuk (C1-3 spinolaminar) line passes through or 1 mm anterior to the C2 posterior arch cortex. If the C2 posterior arch cortex lies within 1.5 mm posterior to Swischuk line, there is a suspicion for a true underlying injury, while a displacement greater than 2 mm indicates a true dislocation.

Answer 63

**3. Grade 3** ## Footnote * Subclavian steal syndrome results from occlusion of the subclavian artery secondary to atherosclerotic occlusion proximal to the origin of the vertebral artery. On the right side, the disease occurs in the innominate artery. * The severity of the subclavian steal phenomenon is divided into three grades. * Permanent retrograde vertebral flow signifies grade three severity of the disease process. * Grade one includes the reduced antegrade vertebral flow whereas grade two is characterized by the alternating flow - antegrade flow in the diastolic phase and retrograde flow in the systolic phase.

Answer 64

**2. Surgical removal of hemorrhage with cerebellar decompression** ## Footnote * Current guidelines recommend surgical evacuation of cerebellar hemorrhages that are more than 3 cm in diameter. It is supported by the meta-analysis performed from observational studies. * The surgical evacuation was associated with improved survival outcomes with similar rates of functional outcome. * External drainage without posterior fossa decompression may lead to upward herniation of the cerebellar mass and is not the treatment of choice. * Although it lacks randomized control trials, based on the observational studies it has shown a reduction in mortality rate

Answer 65

**2. A 72-year-old female on warfarin with a subacute vertebral compression fracture and 8/10 back pain refractory to pain medication and back bracing** ## Footnote * Vertebroplasty and kyphoplasty are indicated for acute, symptomatic compression fractures that are refractory to conservative management. * An asymptomatic vertebral compression fracture is an absolute contraindication to vertebroplasty and kyphoplasty. * Systemic and local infections such as osteomyelitis and discitis should be treated appropriately before attempting the procedure. * There are risks associated with vertebroplasty and kyphoplasty. Conservative management, including pain medication and bracing, should be considered as the first-line option in treating vertebral compression fractures.

Answer 66

**4. Preoperative embolization** ## Footnote * Meningiomas are the most common extra-axial brain tumors that present with a slow-growing dural-based mass. They are usually isointense to grey matter in both the T1- and T2- weighted images and show vivid, intense and homogeneous enhancement following gadolinium administration. * Meningiomas are highly vascular neoplasms that characteristically show sunburst appearance of vessels in both the pre-contrast and post-contrast MRI. * To reduce intraoperative blood loss, facilitate tumor resection and shorten the operation time, preoperative embolization can be applied to meningiomas. * Angiography for diagnostic purposes is not indicated in meningiomas.

Answer 67

**1. Olfactory groove, sphenoid wing, frontal lobe** ## Footnote * The reported involvement of the vision system points to the compressive effects of a tumor on the visual cortex or the retrobulbar tissues. Even though a tumor occurring elsewhere may have similar effects, it is understood that the closer that tumor is to the visual cortex or retrobulbar space, the more likely the patient will suffer damage to his vision. * The medulla is the farthest from the visual cortex/retrobulbar space among all the options and, as such, is least likely to cause this patient’s complaints. * Bilateral vision loss resulting from compression from a tumor in the retrobulbar space suggests a differential diagnosis of Foster Kennedy syndrome. * The olfactory groove, sphenoid wing, and frontal lobe all lie on or around the orbit, thus can be the cause of visual loss.

Answer 68

**3. Anterior communicating artery aneurysm** ## Footnote * Anterior communicating artery aneurysmal rupture may lead to bleeding into the hypothalamic-pituitary axis (HPA) territory. * Acute hematoma in this region leads to irritation and thereby activating the HPA axis. * The stimulation of the posterior pituitary leads to the excessive release of antidiuretic hormone (ADH), thereby leading to dilutional hyponatremia. * An aneurysmal bleed can lead to hyponatremia following the onset of cerebral salt wasting syndrome (CSW).

Answer 69

**2. Hypertonic saline** ## Footnote * Hypertonic saline is the mainstay of medically managing traumatic intracranial hypertension. * It has been shown to effectively reduce intracranial pressure and improve cerebral and systemic perfusion. * It is safe, has a fast onset, sustained, and protracted action with minimal morbidities. * Mannitol has a risk of acute renal failure and rebound intracranial hypertension.

Answer 70

**2. Neisseria meningitides** ## Footnote * Neisseria meningitides are the most common etiology for bacterial meningitis in children, teens, and young adults. * Fever, neck stiffness, and altered mental status are the classic triad of symptoms for meningitis; however, all three are only present in 41% of cases of bacterial meningitis. * Bacterial meningitis typically results in low glucose and high protein levels in the cerebrospinal fluid. A neutrophil predominance on cell count would be expected. * The diagnosis would be confirmed with bacteria identified on gram stain or culture.

Answer 71

**1. Ventral intermediate thalamus** ## Footnote * Both essential tremor (ET) and parkinsonian tremor respond to deep brain stimulation. * The probe for essential tremor should be placed in the ventral intermediate thalamus. * Medical treatment includes propranolol, ethyl alcohol, and primidone, however, in the setting of treatment-resistance, DBS should be considered. * DBS is approved by the US Food and Drug Administration (FDA) for the treatment of essential tremor, dystonia, Parkinson's disease, and treatment-refractory obsessive- compulsive disorder (OCD).

Answer 72

**3. Choroid plexus papilloma** ## Footnote * Choroid plexus tumors retain the normal architecture of choroid plexus, i.e., frond-like arrangement. However, the cell density will be increased. * They do not show nuclear pleomorphism or necrosis on microscopy. * They show less than 2 mitoses per 10 high power fields. * Choroid plexus carcinomas have more mitoses, show nuclear pleomorphism, and necrosis.

Answer 73

**4. Chemotherapy combined with ventricular radiotherapy** ## Footnote * The presence of large, epithelioid cells with abundant PAS+ cytoplasm mixed with lymphocytes is characteristic of a germinoma. Germinoma accounts for more than 50% of lesions in the pineal region. * Germinomas can be localized or disseminated. Localized pure germinoma is best treated with chemotherapy combined with reduced dose ventricular radiotherapy. Craniospinal irradiation is no longer recommended for localized disease. * Germinomas typically have a very good response to radiation therapy and chemotherapy. They are prognostically better than non-germinomatous lesions. * Surgery is not indicated for germinoma. Localized radiotherapy is associated with a higher risk of relapse.

Answer 74

**4. Posterior lateral nasal nerves** ## Footnote * Test stimulation of maxillary branches is confirmed by paraesthesia of upper teeth and gums. That suggests the tip is superolateral to the target. The physician should redirect the needle caudal and medially. * Test stimulation of greater palatine nerves is confirmed by paraesthesia of hard palate. That suggests the tip is anterior, lateral, and caudal to the target. The physician should redirect the needle caudal and posteromedially. * Test stimulation of lesser palatine nerves is confirmed by paraesthesia of hard palate. That suggests the tip is anterior, lateral, and caudal to the target. The physician should redirect the needle caudal and posteromedially. * Test stimulation of posterior lateral nasal nerves is confirmed by paraesthesia of root of the nose. This is the correct needle placement. Once this target is achieved, radiofrequency ablation should be attempted.

Answer 75

**2. Radiotherapy** ## Footnote * Radiotherapy is suitable for elderly patients or poor surgical candidates. Tumor growth is halted successfully. However, worsening of hearing deficits and cranial neuropathies are common. * Tumor recurrence can also occur and serial follow-up imaging should be taken routinely. Radiation-induced-tumour is also a concern in younger patients. * Microsurgery offers a definitive solution. The goal of microsurgery is complete tumor removal as well as hearing preservation. The different surgical approaches that can be used are translabrynthine, middle fossa and retrosigmoid approach. * The most commonly used approach is retrosigmoid (RS) or the sub-occipital approach. This approach allows hearing preservation while providing adequate exposure.

Answer 76

**4. Dynamic X-ray of the lumbosacral spine** ## Footnote * Over decompression of the spine can weaken the facet joints and the par interarticularis thereby leading to instability. * Joint instability leads to characteristic localized pain, especially during ambulation, due to the irritation of the nerve of Luschka. * The mainstay of diagnosing joint instability is by performing dynamic X-ray images in flexion and extension. * The probability of discitis with a normal erythrocyte sedimentation rate and C-reactive protein values is minimal. There is no sciatica in the patients, so the chance of the recurrent disc at the same level is also low.