Section 10 Flashcards

Question

A 26-year-old female presents to the clinic for evaluation of amenorrhea. She denies being sexually active. She has missed her past four menstrual cycles. Her menarche was at 13, and the periods have been consistently 27-28 days apart. She complains of new headaches. Physical examination is unremarkable, and the patient is found to be of normal weight. Laboratory test reveals negative bHCG with a normal thyroid-stimulating hormone and prolactin level. MRI head showed a 2 cm sellar mass. The patient undergoes transsphenoidal surgery. The histological examination of the specimen shows sheets of differentiated non- keratinizing squamous epithelium with clear cystic fluid and crude papillae around fibrovascular cores. What is the likely mutation associated with this lesion? 1. BRAF 2. MEN 3. RET 4. CTNNB1

Answer 1

**1. BRAF** ## Footnote * Craniopharyngioma is a neoplasm of Rathke pouch. These two theories correlate with the two histologic subtypes of craniopharyngiomas - adamantinomatous craniopharyngioma and papillary craniopharyngioma. * Papillary craniopharyngiomas are primarily seen in adults. Somatic mutation in BRAF has been associated with papillary craniopharyngioma. Craniopharyngiomas have benign histology but malignant behavior. * Somatic mutation in the CTNNB1 is proposed to be responsible for adamantinomatous craniopharyngioma development, which is commonly seen in children. * MEN and RET mutations predispose to multiple endocrine neoplasias which include parathyroid, pituitary, thyroid, and gastrointestinal tumors.

Answer 2

**1. Complete craniospinal irradiation** ## Footnote * Diabetes insipidus is the most common presentation of germinoma involving the suprasellar region. The patient develops enuresis, polyuria, and polydipsia. Serum osmolality is greater than urine osmolality on laboratory evaluation. Desmopressin administration normalized the serum osmolality. * Abnormalities in the hypothalamic-pituitary axis cause panhypopituitarism and endocrinal insufficiency. This patient had hypothyroidism demonstrated by decreased serum TSH and free T4 levels. * Timely diagnosis and treatment are critical for better survival. Tumor staging with imaging and CSF cytology helps to guide the appropriate therapy. Whole ventricular radiation is used in cases of localized pure seminoma. * In patients with positive CSF cytology, more disseminated disease is suspected. Therefore, treatment is more aggressive with craniospinal irradiation for an effective outcome.

Answer 3

**3. Binding to somatostatin receptor 5 (SSTR5), leading to the suppression of insulin secretion** ## Footnote * The patient in the clinical vignette most likely has acromegaly. * Pasireotide is a second-generation somatostatin analog used in the treatment of acromegaly. * Pasireotide preferentially binds to somatostatin receptor 5 and causes a suppression of insulin secretion. * Pasireotide has little impact on glucagon secretion.

Answer 4

**1. Treatment with an oral dopaminergic agonist** ## Footnote * The most likely diagnosis is a prolactinoma. Prolactinomas clinically present because of the mass effect (visual changes) of the tumor or because of hyperprolactinemia (amenorrhea, loss of libido). * Microprolactinomas (less than 1 cm) can present with symptoms of hyperprolactinemia or are detected incidentally on neuroimaging done for other reasons. Macroprolactinomas, on the other hand, often present with mass effects on the surrounding structures. * The preferred treatment for prolactinomas is medical therapy. Cabergoline and bromocriptine are two commonly used dopamine agonists. * Transsphenoidal surgery is preferred and is indicated for unsuccessful medical therapy to lower prolactin levels and decrease tumor size after several months of maximum dose medical treatment. It can also be considered in a female with a large prolactinoma (more than 3 cm) who wishes to become pregnant.

Answer 5

**4. 80%** ## Footnote * According to the Hunt and Hess classification system for the severity of symptoms, this patient is in grade 4, stuporous with moderate to severe hemiparesis. Her mortality risk, according to this classification system, is 80%. * The Hunt and Hess classification system is used to classify the severity of SAH based on clinical findings and to predict outcome and mortality. There are 5 different grades ranging in the severity of symptoms, which correlate with the overall mortality of SAH. Grade 1: mild headache with slight nuchal rigidity with approximately 30% mortality. Grade 2: severe headache with full nuchal rigidity and no neurologic deficits other than a cranial nerve palsy with approximately 40% mortality. Grade 3: drowsiness or confusion with a mild focal deficit with approximately 50% mortality. Grade 4: stuporous with moderate to severe hemiparesis with approximately 80% mortality. Grade 5: coma with decerebrate posturing with approximately 90% mortality. * The modified Fisher classification describes the amount of blood seen on a head non-contrast computed tomography (CT) scan to predict the likelihood of developing vasospasm: Fisher 0: no blood detected. The incidence of symptomatic vasospasm: 0%. Fisher 1: thin focal or diffuse SAH. The incidence of symptomatic vasospasm: 18%. Fisher 2: thin focal or diffuse SAH with intraventricular hemorrhage. The incidence of symptomatic vasospasm: 35%. Fisher 3: thick focal or diffuse SAH with no intraventricular hemorrhage. The incidence of symptomatic vasospasm: 31%. Fisher 4: thick focal or diffuse SAH with intraventricular hemorrhage. The incidence of symptomatic vasospasm: 68%. * Oral nimodipine should be started to improve the outcome in patients with ruptured cerebral aneurysms.

Answer 6

**4. Humphrey filed analysis** ## Footnote * The clinical scenario is suggestive of a patient having a cataract with temporal disc pallor. There is a history of fever and rash at a young age which is probably the reason for disc pallor. In this scenario, it is important to rule out any brain pathology before any intervention can be done. In this scenario, it is important to do a Humphrey field analysis followed by a CT scan to rule out any field defect and brain pathology. Hence, it is important to do an HFA in this case. * There is a possibility of amblyopia in this case. * Hence surgical intervention should be done under a guarded visual prognosis. * CT scan is mandatory to rule out any intracranial pathology and space-occupying lesion.

Answer 7

**3. Obtain an MRI of the cervical spine** ## Footnote * The next best step for this patient is to obtain an MRI of the cervical spine to evaluate for a disc herniation and/or degenerative changes that may be causing neural foraminal stenosis. * Based on the exam findings, there is likely a right C6 nerve root compression that is causing the patient’s symptoms. C5-C6 and C6-C are the most common levels of disc degeneration. * Referral to a pain specialist or physiatrist for an epidural steroid injection is appropriate after the failure of conservative measures. However, referring healthcare providers should obtain an MRI first to confirm the diagnosis of a compressed nerve root or spinal cord. * Referral for operative treatment is not indicated unless all non- operative measures have been exhausted without improvement and/or the patient is experiencing progressive or severe cervical myelopathy.

Answer 8

**1. The initial volume of the hemorrhage** ## Footnote * Hemorrhagic progression of traumatic cerebral contusion is observed in almost 75% of cases. * Multivariate analysis has shown that the initial volume of the hemorrhage is the most important parameter governing the risk of progression of the contusion. * It accounts for almost 30% predictability of the risk of hemorrhagic progression of the contusion in the follow-up imaging. * This parameter therefore can be a reliable clinical marker in prognosticating clinical outcomes among patients with traumatic brain contusions.

Answer 9

**3. Subdural hemorrhage** ## Footnote * This patient with poor feeding, incessant crying, vomiting, vitreous hemorrhage, and CT scan showing hyperintensities in the lateral ventricles is most likely a case of 'Shaken baby syndrome.' This is an example of countercoup brain injury. The injury occurs when the abuser shakes the baby violently, causing acceleration-deceleration related shearing forces that damage both the axons and cerebral vessels. The bruise on the head could suggest injury of the child against a hard object leading to deceleration injury. * Shaken baby syndrome often presents with subdural hemorrhage and retinal hemorrhage signs. However, it can also sometimes lead to vitreous hemorrhage that makes it difficult to appreciate the retinal hemorrhage. * Traumatic brain injury patients require a thorough general trauma evaluation. These patients need a detailed neurological examination and require a head CT for the initial assessment of brain injury. * Meningitis will also reveal signs of meningeal irritation absent in this patient. Photophobia and not vitreous hemorrhage is the expected ocular finding. Arteriovenous malformation rupture can also present with symptoms of raised headache, poor feeds, and vomiting. However, an ocular exam will not reveal a vitreous hemorrhage. Tuberculous meningitis will not present with symptoms of raised intracranial pressure acutely and will have a longer symptomatic phase.

Answer 10

**1. Before 3 months** ## Footnote * Metopic suture closure starts at 3-4 months of age and is complete at 8-9 months in most individuals. Premature closure before the third month will cause trigonocephaly. * The metopic suture closure starts at the nasion, proceeding superiorly, and terminates at the anterior fontanelle. Approximately 5.1% have the suture open after one year of age. By two years of age, it should have closed. * The metopic suture's physiologic fusion occurs between 3 and 19 months. * A head computed tomographic scan with 3D reconstruction is performed to confirm the diagnosis and plan the surgery. It will show that frontal bones have a triangular shape, hypotelorism, anterior displacement of the coronal sutures, widening of the posterior parietal regions, pterional constriction, and flattening of the supraorbital ridges with lateral orbital hypoplasia.

Answer 11

**1. 3% sodium chloride solution** ## Footnote * This scenario describes symptomatic hyponatremia following subarachnoid hemorrhage (SAH) due to increased anti-diuretic hormone (ADH) secretion. * Hyponatremia following SAH is either due to increased secretion of ADH (majority) or cerebral salt wasting. If the hyponatremia is due to increased ADH, the patient is euvolemic. If the hyponatremia is due to cerebral salt wasting, there is clear evidence of hypovolemia. * Hyponatremia, here, is best treated with hypertonic saline (3% sodium chloride). * Some clinicians prefer normal isotonic saline (0.9% sodium chloride) if they feel hyponatremia is due to cerebral salt wasting alone. Notably, normal saline is avoided in patients with SIADH as it further drops the sodium level. Fluid restriction leads to hypovolemia, which aggravates the risk of cerebral vasospasm. Thereby, the total fluid restriction should be avoided in these people

Answer 12

**1. X-ray lumbar spine** ## Footnote * The X-ray spine is the most rational imaging modality to be advised in an out-patient set up in a patient presenting with localized back pain and no neurological deficits following a fall incident. * X-ray is a readily available, cheap, and reliable imaging modality in evaluating and initial screening patients with a traumatic spinal injury. * It has high efficacy in outlining traumatic osseous spinal injuries such as fractures and subluxation. * It is a reliable tool in safely dichotomizing patients who need further imaging assessments with the help of CT and MRI imaging.

Answer 13

**1. Neoplasm of cranial nerve VIII** ## Footnote * This patient presents with continuous, unilateral tinnitus and hearing loss. Sensorineural hearing loss along with a cerebellopontine angle (CPA) mass on MRI is consistent with the diagnosis of acoustic neuroma. * Tinnitus should be considered a clinical presentation rather than a disease. A neoplastic proliferation of the vestibulocochlear nerve (cranial nerve VIII) can give rise to tinnitus and concomitant hearing loss and vertigo. * Patients usually present with gradually progressive hearing loss and tinnitus. MRI brain is usually the modality of choice and will demonstrate a CPA tumor. Meningioma often demonstrates a "tail" of enhancement, denoting its origin from the meninges rather than from nervous structures. * Careful history with a description of tinnitus along with examination is the key to making an accurate diagnosis. Vascular causes of tinnitus are usually pulsatile in nature, while Meniere causes episodic tinnitus with hearing loss and vertigo and will not demonstrate a mass at the CPA.

Answer 14

**3. Degenerative** ## Footnote * Spondylolisthesis can be congenital or develop during adulthood. * The disorder may result from physical stress to the lower spine from sports, carrying heavy items, trauma, and general wear and tear. * In most cases, it is the degenerative changes in the spinal components that lead to spondylolisthesis. * The condition carries a high morbidity and leads to prolonged disability

Answer 15

**1. Surgery via retrosigmoid approach** ## Footnote * The retrosigmoid approach is the most commonly used approach for the resection of cerebellopontine tumors. * Surgery provides a definitive cure and the choice of surgical approach is influenced by the size of the tumor, the extent of the tumor, and baseline hearing status. * The retrosigmoid approach provides maximal exposure for the resection of the tumor. A combined microscopic/endoscopic approach can help access the intracanalicular portion of the tumor. * Middle fossa and retrosigmoid approaches help to preserve hearing function, but the risk of facial nerve injury is slightly higher with the former.

Answer 16

**3. Dysfunction syndrome** ## Footnote * The dysfunction syndrome is pain, which is caused by the mechanical deformation of structurally impaired soft tissue; this may be due to traumatic, inflammatory, or degenerative processes, causing tissue contraction, scarring, adhesion, or adaptive shortening. * The hallmark is a loss of movement and pain at the end range of motion. In this patient, he has limited side bending to the left, with most of the pain felt at the end, suggesting a dysfunction syndrome. * Successful treatment focuses on patient education and the mobilization of movement in the direction of the patient's dysfunction/pain. The goal is to focus on tissue remodeling, which can be a prolonged process. * Sacroiliac joint disorders would fall under other or nonmechanical syndrome under the Mckenzie classification.

Answer 17

**2. Tuberous sclerosis** ## Footnote * There are several neurological disorders that present with cutaneous signs. * The ash leaf sign is often seen in patients with tuberous sclerosis. * The "ash leaf" sign is a light oblong depigmented patch. * Adenoma sebaceum is the most well-known skin feature of TS but it does not present until after puberty.

Answer 18

**4. Planning for resection of the biopsy tract with resection of the tumor** ## Footnote * A locally aggressive lytic lesion with heterogeneous contrast enhancement on MRI centered in the clivus is most consistent with a skull base chordoma. * Chordomas have a high recurrence rate and can seed the biopsy tract thus the biopsy tract should be included in the surgical resection. * Optimal treatment of chordomas consists of en bloc surgical resection with clean margins followed by high-dose, highly- conformal radiation such as proton beam radiation. * No chemotherapeutic agents have shown to be effective against chordomas.

Answer 19

**3. Lower down the external ventricular drain (EVD) bag for egress of more cerebrospinal fluid (CSF)** ## Footnote * Lundberg A waves, also known as plateau waves, are waveforms of great concern in patients under ICP monitoring via EVD placement. * Lundberg A waves have a duration of 5 to 20 minutes and an amplitude of over 50 mmHg. The presence of a Lundberg A wave signals raised intracranial pressure and warrants immediate steps to relieve the intracranial pressure. * The advantage of ventriculostomy-aided ICP monitoring is its additional therapeutic benefits by allowing egress of CSF and promptly counteracting raised ICP. * Mannitol is another adjunct that can be used wherein there is no EVD placement. CT brain is to be planned only following measures to minimize the raised ICP temporarily.

Answer 20

**2. Penicillin/vancomycin, ceftriaxone, metronidazole** ## Footnote * The rapid diagnosis for fast treatment of this condition is crucial for optimal outcome and decrease the risk of development of complications. Studies have demonstrated that the best strategy for the management of Pott puffy tumor is the combination of medical and surgical treatment to prevent further complications and improve morbidity and mortality. * Once the patient arrives and diagnosis is suspected, the patient should be admitted and started on broad-spectrum IV antibiotic, IV hydration, analgesia, and rapid coordination for imaging studies. Once the diagnosis is confirmed, ENT and neurosurgical (if intracranial component present) consultation should be done. * Broad-spectrum IV antibiotics should be started as soon as the diagnosis is suspected. Coverage should be provided for the most common pathogens, including gram-positive and anaerobes. It is important to choose antibiotics that have adequate blood-brain barrier penetration for central nervous system coverage. Choices include penicillin or vancomycin, 3rd generation cephalosporin, and metronidazole. Once the culture has a final result, guide antibiotic therapy for that specific pathogen. The length of therapy varies but is prolonged and includes 4-8 weeks of IV antibiotic therapy, including postoperative patients. Some small extradural collections are often treated with IV antibiotics, but aspiration/biopsy is highly recommended in order to obtain culture and guide antibiotic therapy. * Although other options, such as option 3 are possible, it is not the best management at this precise moment in the vignette. After ordering the administration of antibiotics, you could focus on administering analgesia, antipyretic medication, and hydration. It could be in combination with the administration of antibiotics. But between the two, antibiotics should come first if the patient is hemodynamically stable.

Answer 21

**2. Speech and language therapy** ## Footnote * The mainstay of treatment in Tapia syndrome is rehabilitation. * Early speech and language therapy involvement and establishing a swallowing rehabilitation program are crucial for a good outcome. * The role of corticosteroids in treating Tapia syndrome remains controversial, without any clear evidence, and should be guided by neurologists. In the absence of contraindications, early steroid therapy may reduce nerve swelling and enhance recovery based on the disease mechanism. * The patient presents left side injury to the hypoglossal (XII) and recurrent laryngeal branch of the vagus (X) nerve. Surgery was performed with a right-side approach and was not the etiology. Surgical exploration is not indicated.

Answer 22

**4. 20 mm Hg** ## Footnote * Normal intracranial pressure (ICP) is between 5-15 mm Hg or 10-20 cm water. ICP often is increased with the administration of succinylcholine. * Pretreatment with defasciculation doses of nondepolarizing neuromuscular blockers reduces the intracranial pressure (ICP) increase in patients undergoing neurosurgery for brain tumors. * The clinical significance of this ICP rise is unclear in the acutely head-injured patient. * Lidocaine and short-acting opiates like fentanyl or remifentanil also may be used in an attempt to ameliorate the rise in ICP during induction.

Answer 23

**3. Aggressive temperature control** ## Footnote * Traumatic brain injury is one of the causes of noninfectious fever in ICU. 4%-37% of patients with TBI experience fever. The reason for this fever is thought to be due to injury to the hypothalamus. When fever is encountered in ICU, first, the infectious causes should be ruled out as they have been in this case. * Aggressive temperature control is mandated in patients with traumatic brain injury as it is shown to reduce mortality in these patients. * Febrile patients can be treated either with antipyretics or physical cooling. * Procalcitonin is a biomarker of bacterial sepsis, which has a role in the de-escalation of antibiotics. It reduces the unnecessary use of antibiotics in the ICU. As this patient has a non-infectious fever, he does not need antibiotics. High procalcitonin levels may be associated with increased mortality in patients with sepsis.

Answer 24

**1. Cerebellar tonsils** ## Footnote * The Arnold Chiari or Chiari I malformation is the herniation of the cerebellar tonsils through the foramen magnum. * In patients with the Chiari I malformation, the bones of the skull base often are underdeveloped, which results in reduced volume of the posterior fossa, the volume of which is inadequate to contain the entire cerebellum, thus cerebellar tonsils are displaced into the cervical canal. * The posterior fossa in Chiari II malformation is even smaller than in Chiari I malformation. The CSF cisterns are poorly developed due to lack of brain cisterns' expansion as a consequence of the in utero derivation of CSF circulation to the neural tube defect, all of which results in hindbrain structures downward herniation with subsequent compression of these structures against the foramen magnum. * In both type I and II, there is CSF flow obstruction by the foramen magnum crowding, and consequently, hydrocephalus and/or syringomyelia formation are possible over time.

Answer 25

**1. It forms the roof of the temporal horn and the lateral wall of the body of the lateral ventricle** ## Footnote * The caudate nucleus is a part of the basal ganglia and is important for memory. * It is a C-shaped part of the brain. * The head and body form the lateral wall of the anterior horn of the lateral ventricle. * The tail forms the roof of the inferior horn of the lateral ventricles.

Answer 26

**3. Increasing intracranial pressure** ## Footnote * The Cushing response indicates increasing intracranial pressure and, towards its latter stages, includes hypertension, bradycardia, and bradypnea. * There is an increase in systolic blood pressure and a widened pulse pressure. * As the condition progresses, breathing will become shallow, and periods of apnea will occur. * If intracranial pressure continues to increase, brain stem activity will cease due to herniation, resulting in respiratory and cardiac arrest.

Answer 27

**2. Sulfonylurea receptor** ## Footnote * The penumbra of the contusion experiences activation of two transcription factors (endothelial mechanosensitive mechanisms), which are the specificity protein 1 (transcription factor1) and nuclear factor kappa-B. The importance of these factors in the control of sulfonylurea receptor 1-transient receptor potential melastatin 4, which forms the regulatory subunit of the NCCa-ATP channel, is of interest in the damage cascade. * Nuclear factor causes central apoptosis, and specificity factor causes fragmentation of the vessels, thereby playing a pivotal role in the hemorrhagic progression of the traumatic contusions. * Progression usually occurs in the first 12 hours but may develop even in the 3–4 days after traumatic brain injury. Contusion progression occurs with a frequency of 63-70%. * Historically, it was postulated that hemorrhagic brain contusion progression occurs secondary to a coagulopathic event associated with traumatic brain injury.

Answer 28

**1. Superficial middle cerebral vein to the transverse sinus** ## Footnote * The vein of Labbe is also known as the inferior anastomotic vein and drains the lateral surface of the temporal lobe. * The vein of Labbe connects the superficial middle cerebral vein to the transverse sinus. * Thrombosis of the vein of Labbe is quite rare and most commonly occurs on the left side. This condition most commonly presents with headaches and seizures. * The superficial middle cerebral vein is connected to the superior sagittal sinus via the superior anastomotic vein (or vein of Trolard).

Answer 29

**1. Intubate and maintain target end-tidal carbon dioxide of 35 to 40 mmHg and pulse oximetry greater than 90%, elevate the head of the bed up to 30 degrees** ## Footnote * Airway adjuncts are indicated in patients not able to maintain an open airway or not able to maintain greater than 90% oxygen saturation with supplementary oxygen. Oxygenation parameters should be monitored using continuous pulse oximetry with a target of greater than 90% oxygen saturation. Ventilation should be monitored with continuous capnography with an end-tidal carbon dioxide target of 35 to 40 mmHg. * Following the strategy of a definitive airway, placement is recommended in the patient with a GCS of less than 9. * Serial neurological examinations allow for early identification of patients with elevated intracranial pressure (ICP), and subsequent implementation of primary bedside interventions to improve venous outflow and reduce metabolic demands. * Initial bedside approaches to increased ICP include elevate the head of the bed 30 degrees, ascertain that the cervical collar is not impeding venous outflow, and appropriate analgesics and sedation.

Answer 30

**2. Cleaning the cat litter box** ## Footnote * In this question, a newborn female is born with hydrocephalus (enlarged head), intracranial calcifications, and chorioretinitis (redness and excessive tearing of the eyes). This triad suggests congenital toxoplasmosis. * Primary infection during pregnancy is considered very high risk for fetal infection. However, pregnant mothers with previous infections do not transmit the disease to their unborn babies. * Risk factors for congenital toxoplasmosis include pregnant mothers consuming raw meat and transmission via household cats. This often occurs while changing cat litter. * Eating unpasteurized dairy products is associated with an increased risk for Listeriosis. Multiple sexual partners increase the risk of developing the herpes simplex virus. Working in a preschool may increase the risk of exposure to Parvovirus B19. Pregnant women with a household cat should avoid changing the litter box to prevent the spread of the parasite Toxoplasma gondii.

Answer 31

**1. Diplopia with a downward gaze** ## Footnote * The nerve that emerges from the dorsal midbrain is the trochlear nerve. * The trochlear nerve is the only cranial nerve to emerge posteriorly. * The trochlear nerve innervates the superior oblique muscle. This abducts, depresses and internally rotates the eye. * Patients with trochlear nerve palsy present wit diplopia and often have a tilt of the head towards the unaffected side as a way of compensating for the visual deficits.

Answer 32

**2. Weeks 4 to 5** ## Footnote * Complete separation of the facial and acoustic nerves occurs between weeks 4 and 5 of gestation. * This is an important reference point for gestational disorders that affect both the facial nerve and auditory systems. * Abnormalities of the facial nerve can occur in combination with ear malformations. * This can allow the surgeon to predict the location of the facial nerve lesion.

Answer 33

**4. Nystagmus** ## Footnote * The neonate in this question has a meningocele or a meningomyelocele. In a meningomyelocele, there is spina bifida cystica with elements of the spinal cord in the cyst. A meningocele is similar, but there are only meninges and CSF in the cyst. * Nystagmus would raise a concern about brainstem dysfunction and is an abnormal finding in this neonate. * Nystagmus is a rhythmic, involuntary oscillation of one or both eyes. If present at birth or in the first 6 months of life is called infantile nystagmus. * Vigorous symmetrical Moro reflex, flat anterior fontanelle, and a strong urinary stream are reassuring findings.

Answer 34

**4. Ventriculoperitoneal shunt** ## Footnote * A patient with myelomeningocele may develop obstructive hydrocephalus. After cerebrospinal fluid cultures are negative, it is best treated with a shunt. A valve with a proximal ventricular catheter and a distal catheter is used. * The catheter is usually placed in the abdomen, but other locations include the heart and lungs. The distal end of the catheter can be located in any tissue with epithelial cells capable of absorbing the incoming CSF. * Ventriculoperitoneal shunts are used to treat hydrocephalus and shunt cerebrospinal fluid from the lateral ventricles into the peritoneum. * Hydrocephalus is a permanent problem and is not treated with serial lumbar punctures or fontanelle taps.

Answer 35

**2. C5-C6** ## Footnote * The description is classic for Erb palsy, a fairly common result of birth trauma that shows involvement of C5-C6 with resultant paralysis. * It is a complication seen in 0.5-4.4% of vaginal deliveries, often associated with shoulder dystocia. Some studies report an incidence of 0.8-1 case per 1000 births. * Spinal roots are much more susceptible to trauma due to absence of perineural and epineural sheaths. * 90% of Erb palsy resolves within a year.

Answer 36

**3. Cerebellopontine angle** ## Footnote * The patient has a schwannoma of the 8th cranial nerve involving the vestibular division. As the tumor grows it puts pressure on the cochlear division causing tinnitus and hearing loss. * As the tumor enlarges, it can impinge on the facial nerve and cerebellar peduncles causing both peripheral facial palsy and cerebellar signs. * The diagnosis of an acoustic neuroma is made with a contrast magnetic resonance imaging (MRI) or a computed tomogram scan. Contrast is essential; otherwise, the non-enhanced scan can miss small tumors. * They cause 5 to 10% of all intracranial neoplasias in adults.

Answer 37

**1. 1p** ## Footnote * The imaging features are suggestive of oligodendroglioma. * Oligodendrogliomas are usually associated with a combined loss of 1p and 19q chromosomes. * A loss of 1p or a combined loss of 1p and 19q is associated with longer survival. * The other chromosome losses have not been found to be associated with survival in oligodendrogliomas.

Answer 38

**3. Aneurysmal compression** ## Footnote * This patient with a fixed and dilated pupil, headache, likely autosomal dominant polycystic kidney disease (ADPKD) with secondary hypertension, probable mitral valve prolapse, and basilar hyperintensities on CT most likely has developed subarachnoid hemorrhage secondary to aneurysmal rupture. * The external layer of the oculomotor nerve consists of parasympathetic fibers, while the internal structures consist of motor fibers to levator palpebrae superioris and extraocular muscles. The outer layer is prone to pressure effects from epidural hematomas, aneurysms, etc. The inner layer is more prone to vascular insults like vasculopathy, infarcts, or even toxins. * Given his history of likely ADPKD, this patient should be further evaluated for aneurysms in the circle of Willis. A surgical repair of the compressing aneurysm should relieve the pupillary defect. * Diabetic neuropathy is caused by injury to the microvasculature and would present with extraocular muscle palsy rather than a pupillary defect. CT scan reveals the absence of epidural hematoma and hence is not likely in this patient. The patient should be evaluated further for the apical mass in the lung. However, it is on the right side, while the pupillary defect is on the left. A Pancoast tumor would involve the entire sympathetic trunk leading to Horner syndrome, which includes a miotic pupil rather than a dilated fixed pupil.

Answer 39

**2. Perform a needle aspiration and culture** ## Footnote * Whenever an infant develops a decline in general well-being or fever, bacterial sepsis should be suspected. * This patient has cephalohematoma. Usually, it is a benign condition that resolves spontaneously, but rarely certain complications may occur. Due to the delivery circumstances and the clinical features noted on this patient’s presentation, infection of the cephalohematoma should be considered. * In addition to further imaging (to characterize the deformity as an abscess and rule out underlying osteomyelitis) as well as broad-spectrum antimicrobial therapy, in order to definitely determine an infected cephalohematoma as the source of infection, the next best step in management is to refer the patient to pediatric surgery to perform a needle aspiration and culture. * Due to the potential for sepsis, reassurance is not appropriate. Admitting the patient to the wards is appropriate, but the clinician should definitively diagnose the condition via needle aspiration and identify the bacterial organism before providing a prolonged course of antimicrobials. Serial hematocrits are necessary if there is a concern for ongoing hemorrhage, but the patient’s brain imaging did not indicate this.

Answer 40

**3. Posterior interosseous nerve syndrome** ## Footnote * The posterior interosseous nerve (PIN) is a deep branch of the radial nerve arising at the level of the lateral epicondyle of the humerus. * The PIN provides purely motor innervation to the abductor pollicis longus, extensor pollicis brevis, extensor carpi radialis brevis, extensor pollicis longus, extensor indicis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and supinator muscles. * Entrapment or injury to the PIN would result in weakness of wrist, thumb and finger extension, and forearm supination. * Extensor digitorum rupture or rupture of other extensor tendons would result in loss of active extension of fingers. Wartenberg syndrome involves the superficial branch of radial nerve, which provides sensory innervation to the proximal dorsal aspect of the first 3 and 1/2 fingers and the dorsal aspect of the hand. Wartenberg syndrome is purely sensory, and no weakness of wrist or hand is noted. The anterior interosseous nerve is principally a motor nerve that arises from the median nerve with the syndrome presenting as weakness in a median nerve distribution.

Answer 41

**1. Head of the caudate and anterior limb of the internal capsule** ## Footnote * The recurrent artery of Heubner (RAH), a branch of the anterior cerebral artery, supplies the inferior aspect of the anterior limb of the internal capsule and inferior part of the head of the caudate. * The involvement of the RAH thereby results in the disorder of diminished motivation like abulia and akinetic mutism along with hemiparesis with fasciobrachiocrural predominance. * The ultra-early diagnosis of the infarction in the caudate region due to the involvement of the recurrent artery of Heubner can be facilitated with magnetic resonance imaging (MRI) of the brain with special sequences such as diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC). * On the contrary, in case of involvement of the medial lenticulostriate vessel, there is the involvement of the anterior part of the head of the caudate nucleus only. During the involvement of the lateral lenticulostriate vessel, there is an involvement of the caudate, anterior limb of the internal capsule as well as the putamen.

Answer 42

**4. Ketamine** ## Footnote * Motor-evoked potentials are a form of neurophysiologic monitoring used to evaluate the integrity of the motor pathways during surgery. Motor-evoked potentials are most commonly utilized during surgeries involving the brain or spinal cord. * Motor-evoked potentials are very sensitive to physiologic and pharmacologic changes, including changes in anesthetic depth, hypotension, hypoxia, and hypothermia. During MEP monitoring, it is important to maintain a steady state of anesthesia and avoid physiologic derangements that may impact motor evoked potential signals. * The addition of ketamine can amplify weak baseline motor- evoked potentials. Halogenated inhaled anesthetics and nitrous oxide reduce motor-evoked potentials. Propofol, benzodiazepines, and opioids reduce motor evoked potentials, although to a lesser extent than inhaled anesthetics. Dexmedetomidine and opioids have minimal impact on motor evoked potentials. * Intraoperative changes in MEP amplitude or latency could indicate damage to the motor pathways and must trigger discussion between the surgeon, anesthesia provider, and neurophysiologist to determine the source of change.

Answer 43

**3. Parasympathetic fibers and second-order neurons within the pterygopalatine fossa** ## Footnote * Parasympathetic innervation through the sphenopalatine ganglia originates in the superior salivatory nucleus in the pons. Parasympathetic fibers run in the nervus intermedius, a branch of the facial nerve, through the geniculate ganglion to form the greater petrosal nerve (GPN). Parasympathetic fibers synapse in the SPG. Second-order neurons then provide secretomotor function to the nasal, oral, and pharyngeal mucous membranes, the lacrimal glands, and branches to the meningeal and cerebral blood vessels. * The sphenopalatine ganglion also provides sensory innervation to the nasal membranes, soft palate, and parts of the pharynx via the maxillary branch of the trigeminal nerve. * Sphenopalatine ganglion blocks may be considered in the setting of acute, intractable, cluster headache. * Because of autonomic input from the sphenopalatine ganglia, blockade of the ganglion may be associated with transient nausea and dizziness. This should be communicated to the patient while obtaining informed consent.

Answer 44

**3. Lumbar puncture** ## Footnote * To rule out subarachnoid hemorrhage, lumbar puncture is the next best step to measure the cell counts and to look for xanthochromia of cerebrospinal fluid (CSF). CSF xanthochromia due to hemoglobin breakdown products may take 4 hours to develop, but it is almost 100% sensitive between 12 hours and one week. * A head CT scan without contrast is the initial test for a suspected ruptured cerebral aneurysm causing subarachnoid hemorrhage (SAH). It is 100% sensitive if it is done within 6 hours of symptoms onset, but sensitivity decreases over time to 95% in 12 hours, 92% in 24 hours, and 50% in one week. * Once the diagnosis of SAH is confirmed, the source of bleeding can be identified with either CT angiography, MRA, or digital subtraction angiography (DSA). * DSA is considered the gold standard for the diagnosis of SAH due to cerebral aneurysm rupture.

Answer 45

**2. Avoid straining, stooping, and blowing the nose** ## Footnote * Conservative management with the head end of bed elevation, bed rest, and avoidance of straining would be the correct answer choice in the case of cerebrospinal fluid (CSF) otorrhea, highlighted in the question above. The majority of temporal bone fractures and especially CSF leaks will heal on their own. * The precautions provided, among others, help to decrease intracranial pressure and allow for the preservation of CSF intracranially, as well as preventing further damage to the leak site. * Workup with beta-transferrin, determining fluid dextrose concentration, or clinical halo sign would all be appropriate to identify a CSF leak. * Oral amoxicillin would not be appropriate in this patient due to his lack of symptoms of acute otitis media. The patient in question is having episodes of cerebrospinal fluid (CSF) otorrhea likely from an ipsilateral temporal bone fracture. This can initially be treated with conservative measures before further surgical evaluation is warranted. CSF can be identified with the pathognomonic positive halo sign when mixed with blood. Surgical repair would not be appropriate in this patient unless he failed conservative measures. The majority of CSF leaks will heal on there own over time and with conservative treatment. Evaluation of the clear CSF with a glucose stick can be beneficial, as CSF has higher glucose concentration than either mucus or purulent drainage. Ciprofloxacin otic would not be appropriate in this patient due to his lack of acute otitis externa. The patient in question had a recent temporal bone fracture with clear otorrhea, which is likely cerebrospinal fluid (CSF). Work up with either a dextrose stick or the clinical “halo sign” would help identify the clear fluid as CSF. Most CSF leaks resolve spontaneously or with conservative measures to decrease intracranial pressure

Answer 46

**1. Radial nerve** ## Footnote * The brachioradialis muscle is innervated by the radial nerve. The clinician taps the brachioradialis muscle to elicit the Bekhterev-Jacobsohn reflex. * A positive or abnormal response on the Bekhterev-Jacobsohn reflex test is the abduction of the wrist and definite flexion of the fingers. * The Bekhterev-Jacobsohn reflex can be used in association with the Hoffman sign in the upper extremity to determine if there is an upper motor neuron lesion. * The brachioradialis is the muscle that is used to elicit the Bekhterev-Jacobsohn reflex. The ulnar nerve innervates the flexor muscles of the forearm and hand except for the brachioradialis.

Answer 47

**3. Inhibiting prolactin release** ## Footnote * One of the pituitary causes of amenorrhea is hyperprolactinemia. * As a dopamine D2 receptor agonist, bromocriptine inhibits prolactin release. * It is also an agonist at various serotonin receptors and inhibits glutamate release. * Bromocriptine is used in the treatment of prolactinoma, Parkinson disease, and type 2 diabetes.

Answer 48

**4. Lorazepam 4 mg IV** ## Footnote * Patients with intracranial pathology often complain of pain. However, acute pain does not cause a decrease in the conscious level and more frequently presents with tachycardia. * Seizures are a common presentation for patients with acute intracranial pathology and present with an acute decline in GCS with or without convulsion. Seizures may terminate spontaneously but are often treated with anticonvulsant medication in the emergency setting. In this case, the cause of a drop in GCS could be a subclinical seizure, for which Lorazepam or Diazepam should be administered as the initial drug. Another cause of the drop in GCS is an expanding hematoma, but there are no signs to suggest the same in the scenario given. * In a patient diagnosed with intracranial hemorrhage, treating a systolic blood pressure of less than 140 mmHg may reduce cerebral perfusion pressure, especially if their intracranial pressure is raised. * Quick administration of fluid in patients who have a normal circulatory function and no acute blood loss may cause sudden spikes in blood pressure, which may increase the risk of a rebleed.

Answer 49

**4. Intrinsic pontine glioma** ## Footnote * The patient is having a clinical and radiological diagnosis of intrinsic pontine glioma. * Cranial nerves VI and VII arise from the pons. * Intrinsic pontine glioma is usually a radiological diagnosis. * The prognosis is poor for this type of lesions.

Answer 50

**1. P1: Pre-communicating** ## Footnote * An aneurysm is a focal ballooning of the arterial vessel due to weakness within its wall. Rupture of an intracranial aneurysm is responsible for approximately 80% of subarachnoid hemorrhage. * The posterior cerebral arteries (PCAs) are the terminal branches of the vertebrobasilar artery. * From the basilar bifurcation to the junction with the posterior communicating artery, the proximal segment (P1) of PCA gives numbers of important perforating branches that supply the brainstem, thalamus, oculomotor and trochlear nuclei. * P2 courses between the junction and the posterior aspect of the midbrain where it gives thalamoperforating, thalamogeniculate, peduncular perforating, posterior choroidal, and posterior temporal arteries. The distal part of PCA (P3 and P4) extends from the quadrigeminal plate to the calcarine fissure, where they supply the occipital lobe, part of the parietal and temporal lobe and the posterior third of the medial brain hemisphere.

Answer 51

**2. L4/5 microdiscectomy through a midline approach** ## Footnote * This clinical presentation is consistent with a recurrent lumbar disc herniation. * A recurrent herniation can be treated the same way as any other disc herniation with no evidence of instability or significant back pain. * If conservative measures fail, revision microdiscectomy is the most appropriate treatment. * A midline approach is the most appropriate for a paracentral disc herniation.

Answer 52

**2. Beta-catenin** ## Footnote * In healthy cells, the canonical pathway remains inactive due to the absence of WNT, which results in low cytoplasmic concentrations of beta-catenin. * The pathway is activated through the binding of WNT to the Frizzled (FZD) receptor protein on the neuronal cell surface. FZD then phosphorylates Disheveled (DSH), which in turn inactivates the multimeric protein complex responsible for beta- catenin degradation. * Normally, a multi-protein complex comprised of axin, adenomatous polyposis coli, casein kinase 1a, and glycogen synthase kinase 3 (GSK3) binds and phosphorylates beta- catenin, subsequently promoting polyubiquitination and complete proteolysis. A second mechanism uses a different protein complex with presenilin 1 to achieve the same phosphorylation-dependent ß-catenin degradation. * Medulloblastoma-wingless (WNT-MB) cases demonstrate somatic mutations in CTNNB1 (86%), the gene encoding beta- catenin on chromosome 6. Mutations cluster on serine residues that serve as phosphorylation sites for beta-catenin degradation (S33 and S37). Thus, mutation at these key sites leads to constitutive activation of beta-catenin, facilitating neoplastic transformation.

Answer 53

**3. Large breasts bilaterally** ## Footnote * In an otherwise healthy female without risk factors for primary spine disease or breast malignancy, a prevalent cause of thoracic spine pain is large pendulous breasts with poor breast support utilization. * If additional history and exam confirm this, better breast support would be an essential initial step in management. * While it is important to determine breast cancer risk factors in any clinical presentation, which may portend risk for advanced breast cancer, breast cancer gene (BRCA) family history positivity necessitates the need for primary breast cancer screening intensification. Still, it is less likely to offer a clue for the back pain itself as metastatic malignancy is a less likely scenario in this case. * Breast imaging is premature in the absence of clinical breast cancer risk, and ultrasound would be a better first choice (followed by mammogram) in imaging as an initial modality in a 20's year-old if screening were felt to be indicated.

Answer 54

**3. Cingulate gyrus** ## Footnote * The most common type of intracranial herniation is subfalcine, causing a mass effect on the frontal lobe due to a space- occupying lesion. * Subfalcine hernias may present with very subtle clinical symptoms. The hernia may be missed because the symptoms do not warrant neural imaging. * When patients develop a subfalcine hernia, the cingulate gyrus is forced under the falx cerebri, and decreased blood flow caused by compression of the ipsilateral anterior cerebral artery (ACA) results in contralateral leg weakness. * Subfalcine hernias may present with subtle clinical symptoms that progress to uncal or central herniation syndromes.

Answer 55

**4. A dural based intracranial tumor** ## Footnote * Neurofibromatosis type II is one of the neurocutaneous syndromes usually associated with multiple meningiomas and acoustic neuroma so-known as vestibular schwannoma. * Meningiomas are primary extra-axial dural based tumors that arise from the meninges of the brain or spinal cord and commonly seen in Neurofibromatosis type II. Optic gliomas, on the other hand, is usually seen in patients with neurofibromatosis type I. * Subependymal giant cell astrocytoma is usually seen in patients with tuberous sclerosis but unlike meningioma, it is not a dural based lesion. It usually arises from the brain ventricles which might cause symptoms of obstructive hydrocephalus. Whereas optic glioma can lead to gradual vision loss and proptosis of the eye. * Usually, meningiomas are benign, and their presence depends on their location in the central nervous system. Upper motor neuron signs are typically seen in intracranial meningiomas.

Answer 56

**1. L2-L3** ## Footnote * The spinal cord ends at L3 in newborns and migrates upward throughout childhood. * One of the complications from needle insertion directly into a nerve root or the spinal cord is decreased motor function which may persist long-term. * Pain or paresthesia during spinal will warn the anesthesiologist to withdraw the needle slightly, which may minimize the likelihood of nerve damage. * In the pediatric population, spinal anesthesia is typically performed after the child is already anesthetized.

Answer 57

**3. Amyloid-related imaging abnormalities-edema** ## Footnote * Aducanumab is a newly approved agent for treating patients with Alzheimer disease (AD) with mild cognitive impairment or mild dementia. * The reported adverse effects are as follows: amyloid related imaging abnormalities-edema (ARIA-E) (35%); ARIA- hemosiderin deposition (ARIA-H) microhemorrhage (19%); ARIA-H superficial siderosis (15%); headache (21%); fall (15%); diarrhea (9%); confusion, delirium, altered mental status, disorientation (8%); hypersensitivity (angioedema, urticaria) (1%); immunogenicity (1%). * ARIA-E can be visualized as brain edema or sulcal effusions, and ARIA-H can be observed as microhemorrhage and superficial siderosis on brain imaging. * During clinical studies, clinical manifestations of ARIA were present in 24% of subjects who demonstrated radiographic ARIA. Symptoms included headache, confusion, delirium, altered mental status, disorientation, dizziness, vision abnormality, and nausea, the most common being headache (13%). ARIA predominantly occurred during the initial titration of therapy of the first eight doses.

Answer 58

**4. Do not inject any additional medication into the facet joint** ## Footnote * The diagnostic lumbar facet joint injection should be terminated if resistance is encountered. * Facet capsule rupture is a potential complication of facet joint injection. * It is estimated that the joint space has a capacity of 1-2 mL. * Once intraarticular access is confirmed, a combination of local anesthetic and corticosteroid may be injected. It is recommended that the volume injected be between 1-1.5 mL, as larger volumes may rupture the joint capsule.

Answer 59

**1. Restricted diffusion on diffusion-weighted MRI** ## Footnote * This patient has an intracranial ependymoma, a group of glial tumors that are derived from the radial glial cells. These tumors often show restricted diffusion on diffusion-weighted images. * In children, older age at presentation is associated with a better prognosis. However, intracranial ependymomas are associated with poor long-term survival. * Anaplastic ependymomas may seed to other parts of the CNS. * Surgical resection may provide effective palliative therapy. After completion of therapy, an MRI of the brain is recommended every three to four months for three years.

Answer 60

**3. Cortisol** ## Footnote * A patient who has had transsphenoidal hypophysectomy for acromegaly is likely to be lacking all of the hormones of the anterior pituitary (GH, ACTH, TSH, FSH, LH, prolactin). * The patient probably has been maintained on a glucocorticoid and thyroxine, both of which should be given in the perioperative period. * Cortisol has several roles within the body, including stimulation of gluconeogenesis, catecholamine production, and activation of antistress and anti-inflammatory pathways. * The posterior pituitary is usually not removed during transsphenoidal hypophysectomy; therefore, the patient is unlikely to require vasopressin therapy.

Answer 61

**2. Compressive neuropathy in the elbow** ## Footnote * Froment's sign tests for palsy of the ulnar nerve. It is performed to see the action of adductor pollicis, which is the muscle of the thumb. * With palsy of the ulnar nerve, the individual will not be able to hold an object by adducting the thumb against the index finger but instead will have to flex the interphalangeal joint to maintain his grip on the paper. * Decreased action of adductor pollicis in an ulnar nerve palsy leads to the development of Froment's sign. * The flexion of the thumb interphalangeal joint is controlled by flexor pollicis longus, which is innervated by the anterior interosseous branch of the median nerve.

Answer 62

**2. Stop the procedure and have the patient document her wishes for end of life care on the corresponding state scope of treatment form** ## Footnote * Communication failure is one of the most common causes of medical error. * A time-out is a key safety tool that is often required for any procedure. It involves confirmation of patient and procedure, and it allows members of the healthcare team to ask questions if they need clarification. * Although some states have statutes (such as Indiana) that clarify that a patient's spoken wishes in the presence of a physician witness are adequate for defense of a physician's treatment, other states (such as Kentucky across the Ohio River) do not. A physician should not proceed without knowing the law in the state of practice unless he/she is willing to allow the issue to be determined by a court after the fact. * Non-emergent procedures should be delayed in order to follow hospital or higher authority ethical and legal precautions.

Answer 63

**3. Complete excision ensuring clear margins** ## Footnote * Pleomorphic adenomas should be completely excised because there is a risk of recurrence. * Recurrence also can occur secondary to inoculation. * Lymph node dissection is not needed. * Malignant degeneration occurs in 10% of people who are not treated.

Answer 64

**4. Hydrocodone with acetaminophen** ## Footnote * Acute cervical and lumbar radiculopathies due to a herniated disc are primarily managed with non-surgical treatments. NSAIDs and physical therapy are first-line treatment modalities if they fail to relieve the patient's pain; an opioid such as hydrocodone can be prescribed for a short time. Long-term use of opioids is not recommended. * The straight leg raise and the absent Achilles deep tendon reflex (DTR) indicate the location of the disc herniation. Another test that can be performed would be to have the patient perform heel and toe walking; heel walking tests the motor function of the L4 nerve root, and toe walking tests the motor function of the S1 nerve root. * Paraspinous muscle spasm is a nonspecific finding. * At this point, the patient should probably be sent for an MRI, although in some cases, therapy and watchful waiting may be in order. This decision would be made based on the severity of the patient's symptoms.

Answer 65

**4. Lateral mass screw fixation** ## Footnote * The patients with complete traumatic spondyloptosis of the cervical spine sometimes can paradoxically present without any neurological deficits during the clinical examination. These patients invariably have concurrent bilateral fractures of the lamina, which are the components of the posterior element of the cervical vertebra (third Denis columns). * Such fractures of the lamina help to prevent compression and the subsequent damage to the spinal cord despite such a higher grade of subluxation. These fractures help to dissipate the intraspinal pressure, thereby preserving the neurological functions in the patient. * Lateral mass screw fixation is the preferable method of posterior implant fixation in cases of higher Meyerding grades of traumatic subluxations. The reduction of the locked facets, lateral mass screw fixation at the subluxation segments, and the translaminar screw placement in the distal normal segment is the preferable method for posterior fixation. * The concurrent fractures of the lamina and the spinous process will obviate the placement of the sublaminar and the interspinous wiring for anatomical stabilization of the spine. Moreover, they are only applied for in-situ fixation of the spine in patients with poor American spinal injury association (ASIA) neurological status for allowing early wheelchair mobilization of such patients.

Answer 66

**1. Avoidance of right C2 pedicle screw** ## Footnote * Vertebral artery injury is a known complication of C2 pars, pedicle, and trans-articular screw insertions. * Therefore, whenever there is disruption of one vertebral artery (either traumatically or iatrogenically), it is of utmost importance to preserve the contralateral vertebral artery to prevent devastating complications of brain stem ischemia. * In such situations, alternate C2 fixation techniques (like lamina- based translaminar screws or sublaminar wiring) can be safe options for contralateral C2 instrumentation. * Disruption of bilateral vertebral arteries can result in major brainstem strokes, causing neurological deficits (lateral medullary syndrome) and even death.

Answer 67

**1. Superior sagittal sinus and superficial temporal vein** ## Footnote * The parietal emissary vein in the parietal bone joins the superior sagittal sinus and branches of the superficial temporal vein on the scalp. * The emissary veins do not contain valves. * These veins connect the superficial veins of the upper face and scalp with the diploic veins of the skull. * Any infection in the face and scalp area can easily be transmitted to the brain via the emissary veins.

Answer 68

**4. To assess associated developmental venous anomaly** ## Footnote * Gradient echo sequences (GRE), not post-contrast sequences, are most sensitive for assessing the number of lesions. * Post-contrast images are, in particular, important to see any associated developmental venous anomaly. * Developmental venous anomaly (DVA), if damaged intraoperatively, leads to brain venous infarction postoperatively. * Mixed cavernous malformation refers to coexistent DVA with a cavernous angioma.

Answer 69

**2. Surgery by 6 to 12 months of age** ## Footnote * Craniosynostosis correction should be done between 6 to 12 months of age when there are no signs of increased intracranial pressure (ICP) or airways obstruction. This correlates with the period of time in which the infant’s brain and head grow the most. The main goal of surgery is to create enough space in the cranial vault for the brain to grow and develop properly as well as to provide the child with a more acceptable appearance. * Left untreated craniosynostosis can affect the development of the child. This is due to restriction for growth of the brain and damage to the brain tissue due to increased ICP. This is why surgery is the most correct treatment. * When surgical intervention is done in a timely manner, has a very good outcome with fairly normal growth and development. Follow up of a further fusion of sutures and head growth is crucial to determine the need for re-intervention in these patients, with a special focus on syndromic craniosynostosis * The child should be managed by an interdisciplinary team, which includes a neurologist. Depending on the type of surgery, the need for the subsequent use of a helmet might arise but is not the mainstay treatment.

Answer 70

**2. Thyroid-stimulating hormone (TSH)** ## Footnote * The patient is most likely having myopathy, secondary to hypothyroidism. Thyroid-stimulating hormone (TSH) should be checked to confirm the diagnosis. * Creatine kinase (CK) is a non-specific test and can be elevated in almost all myopathies. * Electromyography (EMG) may reveal features of myopathy, but it will not differentiate hypothyroid myopathy from other causes of myopathy. * In patients with symmetrical polyneuropathy in glove and stocking distribution, hemoglobin A1c is usually checked to look for underlying diabetes mellitus

Answer 71

**3. Indocyanine green angiography** ## Footnote * Incomplete clipping of the aneurysm can lead to rebleed. The inadvertent clipping of the main branches or the perforators can lead to postoperative vasospasm. * Indocyanine green is an intraoperative, readily available, and safe vascular flow study to ensure complete occlusion of the aneurysm along with validating the patency of the branching vessels and their perforators. * Indocyanine green flow study gives visual confirmation of the flow within the studied vessels. * The endoscopy only helps in visual confirmation of clip placement at the blind surgical corridors. The transcranial Doppler study only ensures flow in the vessels and the perforators, but it does not quantity the flow through them. Hypoperfusion with decreased flow velocity predisposes to vasospasm. It is operator-dependent with high interrater bias. Adenosine injection can help in achieving a temporary cardiac arrest for the purpose of clipping.

Answer 72

**1. Visual changes, ataxic gait, confusion** ## Footnote * Wernicke syndrome is due to thiamine deficiency and seen in malnourished pts like patients with chronic alcohol use disorder; they have lesions in the mamillary bodies. * Korsakoff psychosis consists anterograde and retrograde amnesia, confabulation and confusion. * Treatment is with thiamine replacement; there is little supporting evidence that treatment of comatose patients with dextrose prior to thiamine will precipitate acute Wernicke's encephalopathy. * Patients with delirium tremens will present 3-5 days after last alcohol intake with confusion, agitation, tremors, hallucinations, and increased autonomic activity like tachycardia, fever, elevated BP.

Answer 73

**1. Obtain an upright radiograph and urgent surgical consultation.** ## Footnote * The patient probably has perforated viscus leading to peritonitis. * Perforated viscus with peritonitis is a dreaded complication of the diaphragmatic pacing procedure. The patient would usually present within hours of the surgery with the above symptoms. An upright radiograph would show air under the diaphragm. * Even if the upright radiograph doesn't show air under the diaphragm, the team should have a high index of suspicion for perforated viscus. Urgent surgical consultation with optimal imaging should be done for the diagnosis. * The patient is in septic shock. He should receive fluid resuscitation, blood cultures, and appropriate antibiotics. However, watchful waiting is not an appropriate management strategy as the ultimate treatment of his septic shock is source control.

Answer 74

**3. Mechanical thrombectomy** ## Footnote * MRI scan of the head and neck is not indicated at this time. The patient should immediately receive a tissue plasminogen activator (tPA) such as alteplase and be transferred to an angiography suite for mechanical thrombectomy (MT). * There is no need to delay the treatment with unnecessary testing, and the patient should immediately receive alteplase. * Mechanical thrombectomy (MT) is recommended in this case based on the recent DAWN and DEFUSE-3 trials for anterior circulation. * Everyone should be considered for alteplase administration as per NINDS trial results published in 1993, which showed significant mortality and outcomes benefits of alteplase administration if the patient has arrived in the emergency department (ED) within the three hours window and has no contraindication to alteplase. The patient should first receive alteplase as she is within the tPA window. Although after tPA administration, the patient should be moved to an angiography suite for MT as the symptom onset is within 24 hours, and there is an LVO at the basilar tip, which would require MT.

Answer 75

**3. Evaluate the patient for an open globe injury prior to ONSUS** ## Footnote * Based on the presentation, this patient is at low risk for ICH. However, her injuries are consistent with an open globe or severe ocular injury. The only absolute contraindication for ONSUS is an open globe, and an ophthalmologist should be consulted immediately. * Signs and symptoms of an open globe include visible eyewall defects, severe chemosis, hypotony, and total hyphema. If there is any suspicion of an open globe, avoid performing the study in the affected eye. * Ocular ultrasound is unlikely to expose the fetus to any harm and does not expose the mother to ionizing radiation. This study would NOT be contraindicated if there was no concern for an open globe. * It is worth noting again that the optic nerve sheath diameter (ONSD) has not been well validated in pregnant patients. There is evidence of several pregnancy-related conditions (i.e., preeclampsia) that affect ONSD. Use this study with caution in pregnant and pediatric patients.

Answer 76

**1. Posterior cerebral artery**