Exam 1: Section 2

Abstract

This practical question and answer book contains two full-length practice exams that mimic the tone and scope of the American Board of Psychiatry and Neurology’s certifying exam in neurocritical care. It covers aspects of neurology, neurosurgery, general critical care, and emergency medicine, with rationale and discussion provided in the answers section at the end of each exam. This useful study guide will help prepare critical care fellows and residents from a variety of backgrounds for the ABPN exam, and help test their critical care competencies in general.

Section 2: Answers

• 1. The correct answer is E. The CHA₂DS₂-VASc is used to estimate the annual stroke risk in patients with atrial fibrillation. Each of the following elements is worth one point: congestive heart failure, hypertension, diabetes mellitus, vascular disease, age 65–74 years, or female gender. Additionally, age ≥ 75 or prior stroke/TIA are worth two points. Based on a maximum score of nine points, the annual stroke risk is as follows (from 0 to 9 points, respectively): 0, 1.3, 2.2, 3.2, 4.0, 6.7, 9.8, 9.6, 12.5, and 15.2% [1].

• 2. The correct answer is B. Leukoaraiosis refers to ischemic damage to the subcortical white matter, usually as a result of chronic hypertension, and is most evident on MRI T2/FLAIR sequences. The presence of leukoaraiosis has been shown to be a risk factor for the development of intracranial hemorrhage following tPA administration [2].

• 3. The correct answer is E. Numerous interventions have been trialed to prevent DCI in the setting of SAH, but the majority of them have failed to provide meaningful benefit. These include statins, corticosteroids, magnesium, and nicardipine (in contrast to the calcium channel blocker nimodipine, which is used extensively for this purpose).

• 4. The correct answer is B. This patient’s CT demonstrates pneumoperitoneum, concerning for ruptured viscus. Rapid surgical consultation for possible exploratory laparotomy is mandatory, along with broad spectrum antibiotic administration.

• 5. The correct answer is A. Although structurally similar to GABA, gabapentin does not act on GABA A or GABA B receptors. It does modulate GABA synthesis and bind to voltage-gated calcium channels, and this is one of the mechanisms through which it modulates pain signaling [3].

• 6. The correct answer is E. The description of a rapidly progressive confluent erythematous rash on the face, neck and torso that quickly resolves with conservative management is typical of “vancomycin flushing syndrome” (previously named “red man syndrome”), a mast-cell mediated response that is not a true allergic reaction. Vancomycin is the causative agent, and this syndrome can be prevented by administering the vancomycin over a longer period of time.

• 7. The correct answer is B. A recent meta-analysis has indicated a slightly lower risk of adverse cardiac events with the 600 mg loading dose of clopidogrel compared to the 300 mg dose, without an increased risk of major bleeding events. Both doses are commonly used in practice [4].

• 8. The correct answer is C. Many patients with acute neurologic injury will have an abnormal pattern at some point during their hospitalization. This patient has cluster breathing, which was defined in 1982 by Plum and Posner as irregular clusters of breaths followed by apneic periods of variable duration. This typically results from a lesion in the pneumotaxic center in the upper medulla or lower pons. Cheyne-Stokes respiration is a regular crescendo-decrescendo breathing pattern followed by a period of apnea. Central neurogenic hyperventilation would be sustained hyperventilation, with associated significant respiratory alkalosis. Kussmaul breathing is a deep and labored breathing pattern often secondary to metabolic acidosis, particularly diabetic ketoacidosis or renal failure. Apneustic breathing is sustained deep inspiration lasting for a few seconds followed by rapid exhalation and a brief post expiratory pause [5].

• 9. The correct answer is E. This patient has diffuse alveolar hemorrhage, characterized by diffuse ground glass opacities on chest CT coupled with progressively bloody bronchoalveolar lavage specimens. Autoimmune processes and vasculitides are high on the differential diagnosis. Osler-Weber-Rendu, also known as hereditary hemorrhagic telangiectasis, may present with pulmonary arteriovenous malformations, but these typically present with dyspnea and cyanosis, not DAH [6].

• 10. The correct answer is B. To calculate the estimate change in serum sodium from the infusion of 1 L of any replacement fluid, the following formula can be used: change in serum Na = (replacement fluid Na−serum Na)/(total body water + 1). Total body water (TBW) usually accounts for 60% of lean body weight for men and 50% in women. The proportion of TBW decreases with age, becoming 50% in elderly men and 45% in elderly women. Therefore, in this patient, total body water can be calculated as 50% of his weight (58 kg) which is equal to 29 L. A liter of 0.225% sodium chloride solution contains 1/4 of the amount of sodium in normal saline (i.e. 154/4 = 38.5 mmol/L). The change in serum sodium as calculated from the formula will be (38.5–177)/(29 + 1), which equals −4.6 mEq/L.

• 11. The correct answer is D. The ketogenic diet may be beneficial in cases of super-refractory status epilepticus, based on the observation that mimic the fasting state have proven beneficial in certain cases of childhood epilepsy. As such, the diet is high in fat, low in carbohydrates, and contains sufficient dietary protein [7].

• 12. The correct answer is C. Administration of crystalloid before and after amphotericin B reduces the risk of nephrotoxicity. Reducing the dose of amphotericin B and discontinuing flucytosine can have a detrimental effect on treatment of cryptococcal meningitis, and should not be tried before the much simpler addition of normal saline boluses. Changing the rate of administration of either drug is not expected to have any beneficial effect.

• 13. The correct answer is D. Even if EEG criteria are not met for seizures, this patient’s PLEDs seem to be on the ictal-interictal continuum, and are potentially responsible for her fluctuating mental status. When benzodiazepine trial is inconclusive or unable to be performed, metabolic imaging is the next best way to confirm that the ictal signature coincides with hypermetabolism. Both CT perfusion and SPECT imaging can be used for this purpose, although CT perfusion is faster and more easily obtained in a critically ill patient.

• 14. The correct answer is B. AOD is associated with a high rate of morbidity and mortality, due in part to the fact that a significant force is required to disrupt the complex and strong ligaments that hold the occipital-cervical junction. Sandbags followed by a halo vest are preferred for stabilization as a rigid collar can accentuate the distraction caused by AOD. Traction should be avoided as it can aggravate the distractive mechanism, putting the medulla oblongata, spinal cord, and vertebral arteries at risk. They may lead to further neurological deterioration.

• 15. The correct answer is E. Approximately 90% of emboli in the setting of non-valvular atrial fibrillation originate in the left atrial appendage. This has led to a variety of methods to “seal off” the left atrial appendage, which may be particularly beneficial among patients who cannot tolerate or are not compliant with oral anticoagulation. The Food and Drug Administration (FDA) approved percutaneous left atrial appendage filter placement for this purpose, based in part from data from the PROTECT AF trial [8].

• 16. The correct answer is B. Benedikt syndrome is characterized by cerebellar ataxia, oculomotor nerve palsy, and tremor, with lesions located in the median tegmentum. Both Weber’s syndrome and Claude’s syndrome describe oculomotor nerve palsy and contralateral hemiparesis secondary to midbrain infarcts, with the latter also involving contralateral hemiplegia of the face and tongue. Wallenberg’s syndrome, resulting from a lateral medullary injury, describes ataxia and loss of pain and temperature sensation on the ipsilateral face and contralateral limbs. Dejerine syndrome usually consists of ipsilateral tongue weakness and contralateral limb weakness following a medial medullary injury.

• 17. The correct answer is E. The goal of medication administration in end-of-life care is alleviation or prevention of pain, dyspnea, and other distressing symptoms. Glycopyrrolate is an anticholinergic drug widely used as a preoperative medication to inhibit salivary gland and respiratory secretions; it has also been frequently used in the palliative setting to minimize secretions in both intubated and not intubated patients that are experiencing severe and abundant secretions. The ongoing use of benzodiazepines and opioids is primarily to relieve pain and respiratory distress, and is thus warranted in this patient, even if the side effects of these medications can cause hypotension and respiratory suppression. Vasopressors do not achieve the goal of preventing pain or other discomfort and are primary used to prolong life; therefore, this medication should be discontinued. Antiseizure medications can be continued during comfort care, as reemergence of seizures secondary to withholding of antiseizure medications can be uncomfortable for the patient to experience and for the families to witness [9].

• 18. The correct answer is D. The goal behind triage is to address the patients who are sickest first. When multiple patients are critically ill, one should evaluate and treat them in a way that does the most good for the greatest number of people. In this case, the patient who is most likely to require immediate intervention is the patient who may be having an acute ischemic stroke and is within the tPA window.

• 19. The correct answer is D. The Lindegaard ratio (LR) differentiates between hyperdynamic arterial blood flow and angiographic vasospasm. This can be calculated using transcranial doppler ultrasonography through the following equation: mean flow velocity (MFV) of the middle cerebral artery divided by the MFV of the ipsilateral extracranial proximal internal carotid artery. This ratio tends to increase with severity of symptoms; mild-to-moderate vasospasm is indicated by LR 3–6, and severe vasospasm LR > 6. This patient has LR > 6, therefore suggestive of severe vasospasm [10].

• 20. The correct answer is A. Inhalational injury is the most common cause of death in burn patients. The combination of facial burns and being found in an enclosed space denotes a significant probability of inhalational burns. Further, being found unconscious in a closed space also increases the likelihood of lower respiratory tract injury. Respiratory tract edema, secretions, and debris formation are important consequences of inhalational injury, and airway obstruction from these factors are a cause of significant morbidity and mortality. As such maintaining respiratory tract patency and bronchial clearance are key priorities in the management of these patients. While therapeutic bronchoscopy is an effective technique in aiding in secretion and debris clearance, it should be employed when chest physiotherapy, positioning and tracheal suctioning fail [11].

• 21. The correct answer is E. A number of landmark trials have been performed evaluating potential therapies in ARDS. The most notable of these was the ARDSNet trial comparing lower tidal volumes versus traditional tidal volumes, and established lung-protective ventilation as the standard of care in ARDS. Other evidence-based interventions include prone positioning (the PROSEVA trial), the selective use of neuromuscular blocking agents (the ACURASYS trial), and ECMO (the CESAR trial). The use of HFOV early in ARDS was actually associated with poorer outcomes in a trial by Ferguson et al. [12,13,14,15].

• 22. The correct answer is B. All these patients have pituitary adenomas. Surgical resection is the recommended initial treatment for symptomatic corticotrophic and somatotrophic adenomas. Medical management with dopamine agonists is the preferred initial treatment for lactotrophic macroadenomas, even in the presence of visual disturbances. Patients with lactotrophic macroadenomas that fail medical therapy or wish to avoid dopamine agonist treatment during pregnancy should be referred for surgery.

• 23. The correct answer is C. This patient is in convulsive status epilepticus after having received a significant load of lorazepam but incomplete load of phenytoin. While completion of the phenytoin load is usually a judicious step, this patient has cardiovascular instability as evidence by his hypotension and frequent PVCs, and so continued phenytoin or high dose midazolam is relatively contraindicated. Blood pressure correction with fluid repletion is certainly reasonable, but eradication of his status epilepticus is paramount, and fast escalation in hemodynamic augmentation may lead to flash pulmonary edema or cardiac ischemia in this frail vasculopathic patient.

• 24. The correct answer is E. The patient’s ASIA impairment scale is B, as there is no motor function, but there is a residual sensory function. The SLICS score is 8 (two points for burst fracture, two points for ligamentous injury, three points for incomplete cord injury, and one point for cord compression).

• 25. The correct answer is E. Conventional cerebral angiography with catheter is considered the reference standard for the diagnosis of arteriovenous malformations. However, non-invasive vascular imaging (such as CT or MR angiography) is appropriate as an initial screening tool, or in cases where conventional angiography is unavailable.

• 26. The correct answer is E. This patient has ipsilateral ataxia and facial sensory findings with contralateral arm and leg sensory findings, classic for Wallenberg syndrome. The ataxia in this case is due to compression of the ipsilateral cerebellar peduncle, and not direct involvement of the cerebellum, making A and C incorrect. Ipsilateral Horner’s syndrome is also often present. Despite the risk from his mechanical mitral valve, this patient’s anticoagulation must be temporarily held as expansion and rebleeding in the confined space of the brainstem would likely be catastrophic. Surgical decompression and/or clot extraction is often not recommended for brainstem hemorrhages, and this patient’s lack of evidence of increased ICP makes the possible benefits of such a high-risk surgery even smaller.

• 27. The correct answer is A. Sickle cell disease (SCD) is a multisystem disorder and the most common genetic disease in the United States, affecting 1 in 500 African Americans. The clinical presentation of SCD is variable depending on the type of complication and the body system affected, with some common complications including vaso-occlusive crises, acute chest syndrome, severe chronic anemia, infections, and cerebral infarctions. For children with HbSS or HbSβ⁰ thalassemia (ages 2–16 years), the American Society of Hematology (ASH) guideline panel recommends annual transcranial doppler screening [16].

• 28. The correct answer is E. Bicuspid aortic valve is the most common congenital heart defect, and a significant percentage of patients will have concurrent thoracic aortic aneurysms which may be prone to rupture at a relatively young age. Sharp or tearing chest pain radiating to the back in a patient with a known bicuspid valve should immediately prompt concern for aortic dissection, which includes CT angiography of the chest if the patient is hemodynamically stable [17].

• 29. The correct answer is C. The FLORALI trial revealed a significant decrease in 90-day mortality with HFNO in comparison to NIV in the setting of hypoxemic respiratory failure. Intubation rates between the two groups were similar. Other benefits of HFNO are a decrease in both respiratory rate and anatomic dead space [18].

• 30. The correct answer is E. This patient has experienced a post-tPA intracranial hemorrhage, which carries a significantly increased risk of in-hospital mortality. While there are a number of theoretical treatment options, there are no evidence-based guidelines demonstrating the superiority of one approach over another. Hospital protocols may dictate care in this case, and may include aminocaproic acid, cryoprecipitate, fresh frozen plasma, prothrombin complex concentrate, and recombinant factor VII. Immediate surgical clot retrieval is usually not an option, due to concerns over ongoing coagulopathy [19].

• 31. The correct answer is A. Any of the answer choices are possible etiologies for acute lower GI bleeding. However, the most common cause overall is diverticular disease, followed by hemorrhoids and inflammatory bowel disease, and less often, malignancy [20].

• 32. The correct answer is D. Simple head elevation is an easy maneuver that promotes venous drainage in order to reduce intracranial pressure (ICP). Mannitol and hypertonic saline also have established roles in treating cerebral edema and reducing ICP. Hypothermia, while controversial, has been shown to reduce levels of inflammatory mediators and subsequently reduce ICP. Use of hypothermia may be limited by coagulopathy and cardiac arrhythmias. Dexamethasone has no proven benefit in treating ICP in this setting and may predispose to infectious and metabolic complications [21].

• 33. The correct answer is C. When volume repletion and the use of multiple vasopressors do not achieve adequate hemodynamic stability in brain dead patients, the use of hormone replacement should be considered. Data suggests that in brain death, malfunction of the hypothalamic-pituitary-adrenal axis results in low levels of cortisol and thyroid hormones, which can contribute to hypotension. Levothyroxine infusions in these cases can help improve hemodynamic stability and has been shown to increase the successful procurement of organs [22].

• 34. The correct answer is C. This multi-system trauma patient with a Glasgow Coma Score (GCS) of 6 requires intubation, and rapid sequence intubation (RSI) is the preferred technique of airway management in major trauma. RSI produces quick induction and neuromuscular blockade to facilitate rapid placement of a definitive orotracheal airway. This reduces the likelihood of aspiration, which is particularly important in trauma patients who most likely have not fasted prior to intubation [23].

• 35. The correct answer is C. Cerebral blood flow is normal at 50 mL/100 g/min. Once it drops below 20 mL/100 g/min, slowing is evident on EEG, and the EEG may be isoelectric below 15 mL/100 g/min. Neuronal cell death will occur when CBF drops below 6 mL/100 g/min.

• 36. The correct answer is C. Hemorrhage into the cerebellum, due to the narrow confines of the posterior fossa, creates a high risk of brainstem compression resulting in respiratory insufficiency and, if progressive, herniation. Intraventricular extension is also a well-described complication. The hydrocephalus caused by cerebellar herniation is usually noncommunicating due to obstruction of the fourth ventricle, either by direct compression or via clot formation as a result of intraventricular extension.

• 37. The correct answer is B. Overly aggressive volume repletion and induced hypertension can be deleterious. Instead, gentle escalation in hemodynamic augmentation and urgent confirmation of ischemia can identify whether or not the patient requires intra-arterial therapy. Albumin and magnesium once held promise as treatment options for delayed cerebral ischemia, but this has not borne out in randomized clinical trials. Intraventricular calcium channel blockade is usually reserved for distal vasospasm, and may be considered after perfusion imaging and conventional angiography.

• 38. The correct answer is C. In the Spetzler-Martin grading system for arteriovenous malformations, the following are considered eloquent areas: the sensorimotor, language, and visual cortices; hypothalamus and thalamus; internal capsule; brain stem; cerebellar peduncles; and finally, the deep cerebellar nuclei. Surgical resection of AVMs adjacent to these areas carries a greater risk of disabling neurological deficits than excision of AVMs in less critical regions. Areas such as the anterior frontal or temporal lobes or the cerebellar cortex are considered non-eloquent. For the purpose of grading, Wada testing or mapping techniques to localize eloquent cortex precisely are not required [24].

• 39. The correct answer is A. A substance with a reflection coefficient of 1 is completely excluded by the blood-brain barrier, while a substance with a reflection coefficient of 0 is completely penetrant. The basis for hypertonic saline’s osmotic effect is the reflection coefficient of sodium chloride, which is 1. The coefficients of the other substances in descending order are: mannitol (0.9), glycerol (0.59), and urea (0.48) [25].

• 40. The correct answer is E. Transient rises in serum ALT are relatively common in patients following amiodarone administration. The incidence of true life-threatening hepatotoxicity, however, is quite rare. In this patient with a mild elevation of her ALT with no other abnormalities, and for whom good rate control has been achieved, it is reasonable to continue the infusion [26].

• 41. The correct answer is B. There are many theories regarding the development in ARDS in the setting of SAH. One of the most prominent is “blast theory”, in which the initial catecholamine surge in SAH results in a shift of blood from the systemic to the low resistance pulmonary circulation, resulting in both endothelial injury and capillary hydrostatic edema. This is most accurately categorized as neurogenic and non-cardiogenic. Classic pulmonary edema is non-neurogenic and cardiogenic, while heart failure secondary to stress cardiomyopathy or infarction secondary to SAH would be both neurogenic and cardiogenic [27].

• 42. The correct answer is D. The Frank-Starling mechanism describes increases in cardiac contractility and stroke volume as a result of increases in left-ventricular end-diastolic volume. This is equivalent to an increase in preload.

• 43. The correct answer is C. This patient has ventilator-associated pneumonia, which is defined as a pneumonia occurring >48 h after endotracheal intubation. IDSA guidelines recommend that noninvasive sampling with semiquantitative culture be used to diagnose ventilator associated pneumonia, rather than invasive sampling methods. Invasive sampling methods include bronchoscopy techniques such as bronchoalveolar lavage (BAL), protected specimen brush (PSB), and blind bronchial sampling (i.e., mini-BAL). Noninvasive respiratory sampling refers to endotracheal aspiration. There is no evidence that invasive microbiological sampling with quantitative cultures improves clinical outcomes compared with noninvasive sampling with either quantitative or semiquantitative cultures. Additionally, noninvasive sampling can be done more rapidly than invasive sampling, with fewer complications and utilizing fewer resources [28].

• 44. The correct answer is A. Given the presentation, this patient likely has a traumatic hemothorax, and requires large bore tube thoracostomy. 8 French is too small, as it will be more likely to clot off (compared to a 24 French tube). Surgical intervention may be necessary if there is immediate bloody drainage of >20 mL/kg or 1500 mL. In the setting of trauma and hypovolemic shock, the patient should be resuscitated with packed red cells, not crystalloid.

• 45. The correct answer is E. This patient presents with a positive QuantiFERON gold test, no infectious symptoms per his family, and on isoniazid monotherapy as an outpatient. This is consistent with the treatment of latent tuberculosis (TB). These patients do not require negative pressure isolation (they are not contagious), nor do they require the escalation of care reserved for active TB infections.

• 46. The correct answer is B. Central fever is a diagnosis of exclusion that is hypothesized to be caused at least in part by inflammatory markers triggered by extreme physiologic stress in acute neurologic injury, and may be mediated by the presence of hemolyzed blood. Central fever is characterized by fevers that occur within 72 h of acute brain injury and persist for more than 6 h in 2 or more consecutive days. Before making a diagnosis of central fever, infectious causes should be ruled out with a physical exam, chest radiograph, and appropriate cultures. Any long-standing venous catheter should be removed, and deep venous thrombosis should be ruled out with ultrasound. Certain biomarkers have been developed to differentiate infectious from noninfectious causes, including serum procalcitonin (PCT). PCT of 0.5 ng/mL or greater was useful in differentiating infectious fever from central fever in patients with SAH and ICH, with high specificity and a reasonably high negative predictive value. Given the high risk of antibiotic overuse and the associated risk of the emergence of resistant microorganisms, antibiotics should be used judiciously in patients with neurologic injury and would not be warranted before proper fever workup in a hemodynamically stable patient [29].

• 47. The correct answer is A. HIT is the result of the formation of antibodies to circulating platelets. The development of HIT, somewhat paradoxically, is linked to increase risk of thrombotic adverse events. Therefore, the discontinuation of heparin products alone is insufficient. Danaparoid, fondaparinux, or argatroban are all acceptable treatment options.

• 48. The correct answer is A. Perflutren lipid microspheres are an ultrasound contrast agent. They are usually injected through a peripheral IV, with an echocardiogram probe placed on the heart. As the contrast material reaches the heart, the left ventricular chamber becomes opacified, the endocardium becomes easier to visualize, and the presence of a left ventricular thrombus may be detected (though transesophageal echocardiogram is more sensitive.) Perflutren lipid microspheres are not used in the diagnosis of cerebral venous thrombus, cerebral arterial thrombus, or deep venous thrombus.

• 49. The correct answer is E. In the setting of hemorrhagic shock, blood product transfusion is not titrated to hemoglobin concentrations. Rather, blood products are titrated to hemodynamic parameters.

• 50. The correct answer is A. A normal ICP waveforms has a descending triphasic morphology. In the waveform shown, the second peak is higher than the first, a general indicator of intracranial hypertension and impaired brain compliance.

• 51. The correct answer is C. Patients with impaired kidney function who receive gadolinium are at risk of nephrogenic systemic fibrosis (NSF), a severe and potentially life-threatening disorder involving fibrosis of both the skin and internal organs. Although NSF has been reported in patients with a GFR less than 60 mL/min/1.73 m², the risk is greatest when gadolinium is administered to patients with a GFR less than 30 mL/min/1.73 m².

• 52. The correct answer is A. The Functional Outcome in Patients with Primary Intracerebral Hemorrhage (FUNC) score is used to predict the likelihood of functional independence at 90 days, and was last validated in 2013. The values needed to calculate the score are ICH volume, age, ICH location, GCS score, and pre-ICH cognitive impairment. Thus, smoking is not a determinant of outcome in the FUNC score [30].

• 53. The correct answer is E. SvO₂ is measured from the pulmonary artery, while ScvO₂ is measured from the superior vena cava. As such, SvO₂ measurements are more invasive, and inherently pose more risk to the patient. ScvO₂ is usually (though not always) lower than SvO₂ due to high oxygen extraction by the cerebral circulation.

• 54. The correct answer is D. In healthcare, the determination of whether something is value-added is always from the viewpoint of the patient. Value-added are essential to delivering a particular service, are done correctly the first time, and are desired and paid for by the patient.