Exam 1: Section 3

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 3: Answers

• 1. The correct answer is D. The most common overall complication of percutaneous left atrial appendage filter placement is the development of a pericardial effusion, which usually occurs in the first 24 h after the procedure. Shortness of breath, hypotension, and low voltage on the EKG are suggestive of the diagnosis, with echocardiography being the simplest and most effective diagnostic modality.

• 2. The correct answer is C. The characterization of hemorrhagic infarcts is as follows: H1, small hyperdense petechiae; H2, larger confluent hyperdensities without mass effect; PH1, hyperdensity < 30% of the infarct zone with mass effect; and PH2, >30% of the infarct zone with mass effect (or any hemorrhage that extends beyond the infarct zone) [1].

• 3. The correct answer is A. Although all of the answer choices listed may be risk factors for the development of abdominal aortic aneurysms, tobacco use appears to be the greatest risk factor, and consequently, smoking cessation may help to significantly reduce this risk [2].

• 4. The correct answer is B. This patient has penetrating abdominal trauma with evidence of intraperitoneal hemorrhage and signs/symptoms of shock. Based on the ABC score, a retrospectively-derived and prospectively validated prediction tool, he is likely to require massive transfusion. While the optimal ratio of pRBC:FFP:platelets is still unclear, professional society guidelines advocate the achievement of a 2:1 pRBC to FFP ratio with 1 unit of platelets transfused for each 4–6 units of pRBC [3].

• 5. The correct answer is A. CBV is defined as the MTT multiplied by the CBF. It is usually measured in mL/100 g.

• 6. The correct answer is B. Following withdrawal of life support, it is appropriate to administer any medications you would otherwise administer to a patient for purposes of palliation. This includes pre-extubation glycopyrrolate to dry secretions, as well as benzodiazepines or opiates titrated to patient comfort (or surrogates of possible discomfort, such as significant hypertension or tachycardia). These drugs should never be administered solely for the purposes of hastening death and facilitating organ transplantation. Accordingly, paralytics serve no purpose other than inducing respiratory arrest, and may mask signs of patient discomfort.

• 7. The correct answer is D. Although somewhat controversial, “hypertensive emergency” is generally defined as hypertensive crisis (systolic pressure > 180 mmHg or diastolic pressure > 110 mmHg) plus end-organ dysfunction. The more murkily defined “hypertensive urgency” is sometimes used in the setting of hypertensive crisis without end-organ dysfunction [4].

• 8. The correct answer is C. This patient has Takotsubo cardiomyopathy, which is a transient stress-related cardiac syndrome characterized by left ventricular apical akinesis and impaired systolic function. Noninvasive positive pressure ventilation is effective in treating pulmonary edema in this setting, and has been shown to decrease intubation rates. The echo findings are characteristic of this type of cardiomyopathy and do not fit the distribution of a particular vessel, making cardiac catheterization unnecessary.

• 9. The correct answer is A. The majority of antiepileptic medications increase warfarin metabolism and may result in an unwanted decrease in the serum INR. The notable exception is valproic acid, which competes with warfarin for albumin binding and may result in a rapid increase in the serum INR, particularly in the setting of a valproic acid loading dose [5].

• 10. The correct answer is D. First-line treatment for delirium includes discontinuing unnecessary interventions, placing the patient in a windowed room with natural light, improving sleep quality as much as possible, limiting use of physical restraints, and reorientation for confusion. If these interventions fail, judicious use of sedating medications may be required.

• 11. The correct answer is A. Uremic frost describes crystalline urea deposits on the skin of individuals with severe untreated renal failure. As a result, the serum BUN is usually markedly elevated, often times exceeding 200 mg/dL [6].

• 12. The correct answer is B. The simplified mnemonic “iddy biddy baby doodoo” is often used when estimating the age of bleeding as seen on MRI T1 and T2 sequences. Isointense on T1 and dark on T2 (iddy) is usually 7 h to 3 days old. Bright on T1 and dark on T2 (biddy) is usually 3–7 days old. Bright on both T1 and T2 (baby) is usually 7 days to 3 weeks. Dark on both T1 and T2 (doodoo) is usually >3 weeks old. Hyperacute bleeds (<7 h) are isointense on T1 and bright on T2.

• 13. The correct answer is D. Once a chest tube is placed for traumatic hemothorax, the output should be monitored closely. Though individual trauma center thresholds may differ, per ATLS guidelines, initial chest tube blood output of ≥1.5 L (or 20 mL/kg) or continued blood drainage of ≥3 mL/kg/h. are indications for urgent thoracotomy in order to rapidly identify and intervene on the source of hemorrhage [7].

• 14. The correct answer is E. The tip of a pulmonary artery (PA) catheter, or Swan Ganz catheter, should rest in West zone 3. The balloon holds approximately 1.5 cc of air; overinflation may cause pulmonary artery rupture, one of the most feared complications of PA catheter placement. A normal wedge pressure is between 2 and 10 mmHg. Finally, thermodilution operates according to the Stewart-Hamilton equation, i.e., the rate of blood flow is inversely proportional to the change in temperature over time. The Hering-Breuer reflex describes the inhibition of respiration as a result of over distention of the lung.

• 15. The correct answer is B. Cerebral sinus thrombosis (CVT) often results in venous infarcts and atypical appearing intracranial hemorrhages as a result of elevated venous pressures. Impaired venous outflow may also lead to hydrocephalus and elevated intracranial pressures. There is no established relationship between CVT and aseptic (sterile) meningitis.

• 16. The correct answer is E. The CT angiogram shows bilateral pulmonary emboli. Given that this patient is hemodynamically stable and not in extremis, and has a history of a malignancy with a high predilection for metastatic brain lesions (which tend to bleed easily), a non-contrast head CT should first be performed before administering systemic anticoagulation. If the head CT is unremarkable, the next step would be a continuous heparin infusion. The patient is not ill enough to warrant systemic thrombolytics or cardiothoracic surgery consult at this time (i.e., there is no evidence of right heart strain or hemodynamic compromise).

• 17. The correct answer is E. The only absolute contraindications to prone positioning during mechanical ventilation are spinal instability and unmonitored increased intracranial pressure. Relative contraindications include the presence of an anterior chest tube, pregnancy, and recent pacemaker placement [8].

• 18. The correct answer is D. This patient has severe community acquired pneumonia in the setting of immunosuppression as a result of her recent RA flare and ongoing prednisone use. For patients with severe community acquired pneumonia requiring ICU admission, Infectious Disease Society of America guidelines recommend use of an antipneumococcal ß-lactam (i.e., ceftriaxone, cefotaxime, ampicillin-sulbactam) plus azithromycin or a respiratory fluoroquinolone (moxifloxacin, gemifloxacin, or levofloxacin). In addition, this patient has been on a significant dose of glucocorticoid (greater than 20 mg of prednisone for 1 month or longer) in addition to receiving methotrexate weekly for RA, which also puts her at risk for Pneumocystis (PCP) infection. As she has not been on prophylaxis for PCP, she should also be empirically treated with trimethoprim-sulfamethoxazole [9].

• 19. The correct answer is E. This patient’s 4 T score places her in the low-risk category (0–3), meaning her risk of having heparin induced thrombocytopenia (HIT) is sufficiently low that no further testing is required at this time. Sending the heparin PF4 immunoassay is more likely to result in a false-positive result in this setting, subjecting the patient to unnecessary further testing and necessitating the discontinuation of all heparin products while awaiting the results.

• 20. The correct answer is E. cEEG has been studied extensively in the setting of subarachnoid hemorrhage, particularly in regards to predicting the onset of vasospasm and delayed cerebral ischemia. In one study, relative alpha variability was shown to precede the onset of angiographically-proven vasospasm by up to 3 days [10].

• 21. The correct answer is B. A normal SjVO₂ is in the 50–75% range. While there is no compelling data from randomized controlled trials to dictate saturation targets in traumatic brain injury, it is reasonable to avoid prolonged desaturation (<50%), as this may indicate imminent or ongoing ischemia. There is also no evidence to support targeting supratherapeutic values (75–90%).

• 22. The correct answer is C. This patient manifests signs and symptoms consistent with compartment syndrome of the right lower extremity. Timely diagnosis requires a high degree of clinical suspicion based on the injury and clinical presentation. Management is urgent fasciotomy in order to relieve pressure and restore adequate limb perfusion and venous return. Delays in performing fasciotomy can result in muscle necrosis, infection, and limb loss.

• 23. The correct answer is B. The clinical presentation suggests acalculous cholecystitis. Critical illness and neurologic deficits are frequently associated with this diagnosis, and it confers considerably higher morbidity and mortality than its calculous counterpart. While surgical options may be considered, this patient’s overall critical illness and poor healing potential (i.e. very low serum albumin) make her a poor surgical candidate. Therefore, percutaneous cholecystostomy is the best treatment option for this patient.

• 24. The correct answer is C. CIP is a potential complication of various conditions requiring prolonged ICU care, and often initially manifests as difficulty weaning from mechanical ventilation. The development of CIP has been linked to multiple factors, including the simultaneous use of neuromuscular blocking agents and corticosteroids, as well as uncontrolled hyperglycemia. It usually presents as symmetric muscle weakness with diaphragmatic involvement and cranial nerve sparing [11].

• 25. The correct answer is E. Steroids are not currently recommended for the treatment of traumatic spinal cord injuries. Therefore, none of the therapeutic regimens listed would be appropriate [12].

• 26. The correct answer is D. The HAIR score is used to stratify the risk of 30-day mortality in subarachnoid hemorrhage. The components of the HAIR score are as follows: Hunt-Hess grade (H), patient age (A), presence of intraventricular hemorrhage (I), and whether or not the patient experiences re-bleed (R). Aneurysm size is not a consideration [13].

• 27. The correct answer is E. The PATCH study was a prospective randomized trial evaluating platelet transfusion versus standard care in patients with spontaneous cerebral hemorrhage who were also on antiplatelet therapy. The study found that patients in the transfusion group had poorer outcomes at 3 months (both mortality and modified Rankin) compared to standard therapy, along with a higher rate of adverse events during their hospital stay [14].

• 28. The correct answer is A. Although the terms may be used somewhat interchangeably, vasospasm more accurately refers to a radiographic finding, rather than a clinical syndrome. DCI is the appropriate term to describe clinical deterioration which may be a result of cerebral vasospasm. The onset of DCI is usually somewhere between post-bleed days 4 and 10, and the resulting deficits may be quite significant [15].

• 29. The correct answer is C. Data from the CRASH TBI trial clearly demonstrated harm with the use of corticosteroids after blunt TBI. The PROTECT III trial was stopped early for futility, but no harm was detected in patients receiving progesterone. Furosemide and mannitol are common therapies for the management of intracranial pressure [16, 17].

• 30. The correct answer is E. Triphasic wave encephalopathy (TWE) is a relatively nonspecific indicator of a wide range of metabolic, toxic and structural abnormalities. Differentiating which pattern represents a fixed encephalopathy versus a reversible super-imposed condition is challenging. Hepatic, renal, and electrolyte abnormalities should be considered. Benzodiazepine trial is reasonable as well.

• 31. The correct answer is C. A class I view is defined by visualization of the uvula and tonsillar pillars, while a class II view is defined by partial visualization of the uvula and pillars. A class III view is defined by visualization of the hard and soft palate only, and a class IV view is defined by visualization of the hard palate only. There is no Mallampati class V.

• 32. The correct answer is B. Based on a history of COPD and multiple recent hospitalizations, coupled with severe pneumonia requiring ICU admission, coverage is needed for MRSA, Legionella, and Pseudomonas, among others. According to Infectious Disease Society of America guidelines, a ß-lactam and fluoroquinolone are required in this scenario, in addition to either vancomycin or linezolid [9].

• 33. The correct answer is E. Of the choices listed, the only medication lacking an effective reversal agent is fondaparinux. Dabigatran had previously lacked a reversal agent before the introduction of idarucizumab, a monoclonal antibody which rapidly binds the drug. Apixaban also lacked a specific reversal agent prior to FDA approval of andexanet alfa, a recombinant modified factor Xa medication.

• 34. The correct answer is B. While hematochezia often implies a lower GI source of bleeding, a brisk upper GI bleed may be found up to 10% of the time as the source of bleeding. Therefore, especially in cases of hemodynamic instability, an upper endoscopy may be undertaken first in an effort to identify and control the bleeding. Surgical intervention is usually sought after more conservative medical and endoscopic therapies have failed. TIPS procedure may be appropriate in cases of established variceal bleeding [18].

• 35. The correct answer is C. Abdominal compartment syndrome is often an unrecognized cause of organ dysfunction in critically ill patients, due to the inaccuracy of the clinical examination in detecting intra-abdominal hypertension. Oliguric kidney injury may be the earliest sign, where compression of the renal veins leads to increasing venous resistance and lowering of the glomerular filtration rate [19].

• 36. The correct answer is D. Somatosensory evoked potentials (SSEPs) have been used in order to provide some objective measure of neuronal functioning, and by extension, prognosis for recovery in patients with anoxic brain injury. The value of SSEPs in the setting of therapeutic hypothermia is less certain. Activity in response to median nerve stimulation is measured from the brachial plexus, dorsal horns, and thalamocortical radiations with N9, N13 and N20 waveforms, respectively. Therefore, all of the above are correct.

• 37. The correct answer is A. Levetiracetam’s mechanism of action is not entirely understood, but it is thought to exert its effects in part through presynaptic calcium channel inhibition. Sodium channel inhibition is the mechanism by which a number of antiepileptic medications act, including phenytoin, valproate, and carbamazepine. The benzodiazepines, including lorazepam and alprazolam, operate via potentiation of GABA at the GABA receptor. Felbamate operates via NMDA receptor inhibition. Finally, retigabine is a novel anticonvulsant medication that operates by activating voltage gated potassium channels.

• 38. The correct answer is E. This patient is experiencing severe headaches and elevated ICP readings in the setting of a recently clamped EVD. Of the choices listed, the next best step is to open the drain and monitor for clinical improvement. If the patient quickly improves, she may end up requiring a ventriculoperitoneal shunt, although another clamp trial may be attempted.

• 39. The correct answer is A. Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial cytopathy, a group of disorders that also includes Leber’s hereditary optic neuropathy (LHON) and Leigh syndrome. Typical findings may include basal ganglia calcification on head CT, MRI with multifocal cortical infarcts, and elevated creatine kinase and lactate (in both serum and CSF). Triphasic waves are a non-specific finding in a number of encephalopathies, but are not associated with MELAS syndrome.

• 40. The correct answer is E. Although most patients with preeclampsia will be medically managed with relatively few complications, a subset will go on to develop frank eclampsia (tonic-clonic seizure activity). Even after the definitive therapy for preeclampsia (delivery of the fetus and placenta), patients continue to be at risk of late postpartum eclampsia. Cases have been reported up until about 6 weeks postpartum.

• 41. The correct answer is E. Anorexia nervosa is associated with subnormal or erratic vasopressin release. Wolfram syndrome is also known as DIDMOAD (diabetes insipidus, diabetes mellitus, optic atrophy and deafness). It is an autosomal recessive illness with incomplete penetrance, and is also associated with cognitive and psychiatric disorders. Septo-optic dysplasia and other congenital cerebral midline abnormalities have been associated with both anterior and posterior pituitary dysfunction.

• 42. The correct answer is C. Giant cell arteritis is more commonly seen in females of Scandinavian descent, and is uncommon in African Americans. 40–50% of patients with giant cell arteritis have polymyalgia rheumatica, and about 15% of patients with polymyalgia rheumatic have giant cell arteritis. Amaurosis fugax is a classic presentation of giant cell arteritis, but is associated with painless vision loss [20].

• 43. The correct answer is C. The development of both early- and late-seizures has been described as a potential consequence of stroke, with the risk for developing epilepsy appearing to be higher among patients suffering from hemorrhagic infarcts. Although the incidence of late seizures varies based on a number of factors, by 2 years, approximately 10% of ICH patients will develop epilepsy. Risk factors for the development of late seizures may include the development of early seizures, younger age at presentation, ICH volume, and cortical involvement [21].

• 44. The correct answer is E. Contrary to popular belief, the Canadian C-spine Rules do not recommend neck imaging simply for the presence of midline neck tenderness. No further imaging is recommended if the following criteria are met: Age < 65, no extremity paresthesias, and no “dangerous” mechanism (defined as a fall >3 feet, axial load injury, high speed/rollover MVC/ejection, bicycle collision or motorized recreational vehicle). Next, the patient must have at least one low risk feature (defined as sitting position in the ED, ambulatory at any time, delayed onset neck pain, lack of midline tenderness, or simple rear-end MVC). Finally, the patient must be able to rotate their neck at least 45° to the left and right [22].

• 45. The correct answer is B. In airway pressure release ventilation, the primary determinants of oxygenation are the mean airway pressure and the fraction of inspired oxygen. Thus, increasing either of these parameters may improve this patient’s hypoxemia. Increasing T_low would actually decrease the patient’s mean airway pressure by increasing the time spent at the lower set pressure. Both prone positioning and nitric oxide have been shown to improve hypoxemia in severe ARDS, though prone positioning has been linked to improved outcomes and nitric oxide has not.

• 46. The correct answer is C. Evidence suggests that following the development of PRES, different calcineurin inhibitors can be used in this setting without recurrent symptoms. Sirolimus is an m-TOR inhibitor, and is a safe alternative to tacrolimus. Steroids are not the causative agent in this case, nor are they sufficient monotherapy [23].

• 47. The correct answer is B. The CAM-ICU scoring system is a delirium monitoring tool, and is graded dichotomously (delerium is present or absent). It excludes patients with a RASS score of −4 or −5, and involves the use of the Letters Inattention Test, as well as evaluations of disorganized thinking and level of consciousness. It was originally designed with input from geriatricians and neuropsychologists, but can be used in patients of any age group.

• 48. The correct answer is D. In studies of EMS evaluations of stroke symptoms, the most common mistakes were missing symptoms of dizziness or ataxia as stroke signs. Additionally, paramedics often mistake symptom onset as the time the patient awoke (rather than the time last seen normal) [24].

• 49. The correct answer is C. Patients with hyperthyroidism have increase sympathetic responsiveness. As such, any drug with sympathomimetic properties can cause an exaggerated response. A pure peripheral vasoconstrictor is often safer than medications that increase catecholamine release.

• 50. The correct answer is E. Corticosteroids are frontline therapy for the treatment of neurosarcoid. When patients fail steroid therapy, a number of second-line treatments may be explored, including cyclosporine, methotrexate, azathioprine, and even radiation therapy in certain cases. FOLFOX is a chemotherapy regimen used in colorectal cancers, and has no role in the treatment of neurosarcoid.

• 51. The correct answer is A. Patients with ALS usually present with limb weakness initially, which then progresses to involve the trunk and bulbar weakness. Bladder and diaphragmatic dysfunction are late manifestations of the disease [25].

• 52. The correct answer is A. Management of isolated brainstem hemorrhages is somewhat controversial, with surgical options often impractical due to the relative inaccessibility of the clot and limited effectiveness of decompression without clot evacuation. Expectant medical management is often the only viable treatment option.

• 53. The correct answer is E. Permanent pacemaker (PPM) indications typically include severe disease without symptoms or moderate disease with symptoms. These include symptomatic sinus node dysfunction, symptomatic second-degree atrioventricular block (types I and II), and asymptomatic third-degree atrioventricular block; other indications include heart block secondary to neuromuscular diseases, infiltrative diseases (sarcoidosis, amyloidosis), long QT syndrome, and hypertrophic cardiomyopathy. Contraindications for a pacemaker (also known as CRT, or cardiac resynchronization therapy) for heart failure include life expectancy less than 1 year.

• 54. The correct answer is D. Aggressive pulmonary toilet is the most effective measure that will improve the patient’s respiratory status. She is alert, awake, and hemodynamically stable, with rapid improvement in her oxygen saturation. Her head should be elevated up to 45°, and bronchodilators can be used for bronchospasm. Noninvasive ventilation should be avoided as this is a relative contraindication in an aspiration event, especially with an improving patient. The course of an aspiration pneumonitis can be divided into two stages. The first is categorized by coughing and bronchospasm that occur immediately after the aspiration event. The second is categorized by an inflammatory reaction that can occur within 6 h. If the patient continues to worsen and her respiratory status declines leading to mechanical ventilation, antibiotics should be considered at that time given the risk of persistent oropharyngeal aspiration. There is no indication for steroids. The patient’s chest X-ray does not show any evidence of lobar collapse or an aspirated foreign body, and the aspiration involved liquids, meaning bronchoscopy would be of little value [26].