Board Review Questions: April 2016

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  1. In a patient with ataxia, what diagnosis is suggested by a positive Romberg test?
    A. Cerebellar ataxia
    B.      Motor ataxia
    C.      Sensory ataxia
    D.     Vestibular ataxia
  2. In a patient who intentionally overdosed on paroxetine 6 hours earlier but has remained asymptomatic, with normal vital signs and a normal physical examination, which of the following test results is needed to guide management?
    A.      Serum acetaminophen concentration
    B.      Serum ethanol concentration
    C.      Urine drugs of abuse screen
    D.     Urine tricyclic antidepressant screen
  3. A mother brings in her 5-day-old son because she is concerned about his color. She says he has not fed well for the past 24 hours and always seems to be breathing hard. Vital signs are blood pressure 73/44, pulse 120, respirations 65, and temperature 37.2°C (99°F). Physical examination reveals perioral cyanosis and duskiness of the face and trunk. Immediate management includes:
    A. 100% oxygen by nonrebreather mask
    B.      Isotonic crystalloid fluid 20 mL/kg
    C.      Phenylephrine 5 mcg/kg IV bolus
    D.     Synchronized cardioversion at 0.5 to 1 J/kg
  4. A 42-year-old man presents after a motor vehicle crash in which he was the unrestrained driver. He has shortness of breath and pain and crepitance on the right side of his chest. In the ambulance, he became tachycardic, tachypneic, and hypotensive. Symmetrical breath sounds are noted. What is the appropriate next step?
    A. Order chest radiography
    B.      Perform needle decompression of the chest
    C.      Set up for a tube thoracostomy
    D.     Start normal saline 1 L bolus IV
  5. A 35-year-old woman with known myasthenia gravis presents with a fever and right lower quadrant pain. Abdominal CT scanning reveals acute appendicitis. While in the emergency department, she begins to complain of increasing shortness of breath. Vital signs remain stable. What is the appropriate next step?
    A. Administer pyridostigmine
    B.      Measure forced vital capacity
    C.      Perform emergent intubation
    D.     Perform the ice bag test
Answers
  1. The answer is C, Sensory ataxia.
    (Adams, 1009-1011; Tintinalli, 1143)
    A positive Romberg test suggests a diagnosis of sensory ataxia. In a Romberg test, the patient is asked to stand with the feet together and the arms outstretched, initially with the eyes open. Presence of unsteadiness during this phase confirms the ataxia but does not suggest the type. When the eyes are closed, the visual input to balance is lost. If the ataxia worsens after the eyes are closed, the Romberg test is positive, and the ataxia is most likely sensory. Similarly, finger-to-nose testing with the eyes closed is a test of upper extremity posterior column (proprioception) function and indicates a sensory ataxia. Sensory ataxia is primarily due to loss of proprioception or disease of the dorsal/posterior columns of the spinal tracts. Ataxia is broadly divided into three groups: cerebellar (motor), sensory, and vestibular. There is often some overlap either because of location (as in a stroke that affects the vestibular input into the cerebellum) or because the disease process involves multiple pathways (such as loss of proprioception and cerebellar disease). Patients with cerebellar (motor) ataxia have a wide-based gait. When asked to stand with the feet together, even with the eyes open, such a patient is very unsteady and ataxic. With the eyes closed, the ataxia does not get worse (in reality, the patient is extremely unsteady with the eyes open and is unable to stand for more than a few seconds); this is therefore, technically, a negative Romberg test. It is often a point of some confusion: the Romberg test is not positive because of the presence of ataxia, but only if the unsteadiness worsens with loss of visual input. Vestibular ataxia is seen with disorders of the vestibular system. In acute dysfunction, it is often associated with nausea, vomiting, and vertigo. In more chronic conditions, only the ataxia might be present. Optic ataxia, which is a lack of coordination between eye movements and hand movements, is uncommon.
  1. The answer is A, Serum acetaminophen concentration.
    (Marx, 1969-1970, 1966, 1948; Nelson, 81-83, 1053-1054; Wolfson, 1386, 1499)
    In the scenario described in this question, of the choices listed, acetaminophen concentration is the only test result that can or should potentially change medical management. In acetaminophen overdose, signs and symptoms initially are nonspecific or absent; the decision to treat with N-acetylcysteine is guided by measurement of an acetaminophen concentration and determining the time of ingestion. Checking acetaminophen concentration is reasonable in all intentional self-poisonings: acetaminophen is commonly ingested in overdose; it is in multiple preparations; the test is easy and cheap; initial symptoms are nonspecific; fatal liver failure can occur; and the antidote is extremely effective in preventing liver failure if given early. Paroxetine (marketed in the United States as Paxil and Pexeva) is a selective serotonin reuptake inhibitor (SSRI), and in overdose, the clinical course is usually benign. Exceptions include massive overdoses and the SSRI citalopram (brand name Celexa), which unlike other SSRIs can potentially cause cardiac (QT-interval prolongation, bradycardia) and CNS (convulsions) complications. An asymptomatic patient, after an observation period, can be medically cleared. There is no known role for checking serum paroxetine concentrations, nor are they readily available. Quantitative serum ethanol concentrations can potentially be helpful by correlating the result with the clinical manifestations. In the patient described, however, who is asymptomatic with a normal physical examination, knowing the ethanol concentration will not change medical management. Urine drugs of abuse screens rarely affect management of patients who intentionally poison themselves. They are designed to detect exposure to certain drugs (not intoxication) and are plagued by false-positive results and misinterpretation. Signs and symptoms guide the management of most poisonings, not the mere detection of exposure. Although psychiatry consultants often ask for a urine drugs of abuse screen, in almost all cases the results do not and should not guide medical management. Some urine screens have a tricyclic antidepressant test, but false-positive results are common and only detect exposure. Instead, management should be guided by findings such as altered level of consciousness, convulsions, and QRS-interval prolongation.
  1. The answer is A, 100% oxygen by nonrebreather mask.
    (Fleisher, 198-202, 699-701; Marx, 2138-2167)
    Signs of cardiac disease in children can include poor weight gain and feeding issues and other nonspecific findings. The presentation in this question suggests cyanotic congenital heart disease. It can be difficult to distinguish from pulmonary disease, but the best way to differentiate the two is to provide high-flow oxygen and observe the patient’s oxygen saturation and clinical status. In practice, any patient in extremis warrants 100% oxygen, and optimal delivery is by a nonrebreather mask. Cyanotic cardiac disease causes a right-to-left shunting, with a mixture of oxygenated and deoxygenated blood sent to the systemic circulation with subsequent cyanosis. In these children, administering 100% oxygen is not likely to change the patient’s clinical status or coloration because the shunting of the blood remains unchanged. A mnemonic for the five cyanotic congenital cardiac diseases is as follows:
    1 – Truncus arteriosus (1 trunk)
    2 – Transposition of the great vessels (2 vessels)
    3 – Tricuspid atresia (Tri = 3)
    4 – Tetralogy of Fallot (Tet = 4, right ventricular hypertrophy, overriding aorta, pulmonic stenosis, and ventricular septal defect)
    5 – Total anomalous pulmonary venous return (5 letters of “TAPVR”)
    Synchronized cardioversion is reserved for patients who are unstable with supraventricular tachycardia or ventricular tachycardia with pulses. Phenylephrine (correct dosing is 0.01-0.02 mg/kg IV) is given to increase systemic vascular resistance during an episode of shunting associated with tetralogy of Fallot, or a “tet spell.” It can diminish the right-to-left shunting and improve overall circulation. Intravenous hydration is always an important component of resuscitation but is not the first priority. Clearing the airway and resuming breathing for the patient are critical: 80% of all pediatric arrests are respiratory. A full 20 mL/kg infusion can be deleterious if the pump delivering the fluid is not working efficiently (as can happen). If that is suspected, a 10 mL/kg infusion can be given and then repeated if the patient’s clinical status does not worsen.
  1. The answer is B, Perform needle decompression of the chest.
    (Roberts, 179; Wolfson, 82, 129)
    Once the diagnosis of a tension pneumothorax with hypotension is suspected, immediate needle decompression should occur. One study found auscultation to be sensitive in 84% of patients and to have a diagnostic accuracy of only 89% despite a hemothorax or pneumothorax. It is possible for a patient to have a false-negative of symmetrical breath sounds despite having a tension pneumothorax. Insertion of a large-bore catheter is the immediate action. This procedure should not be delayed for a chest radiography or CT. Tube thoracostomy is time consuming and is done later as a followup intervention. Intravenous fluid administration can transiently improve the hypotension caused by a tension pneumothorax but will do nothing to address the tension pneumothorax. The emergency physician should immediately consider and treat without delay apnea, hypotension, or cardiac arrest in an injured patient. The diagnosis is confirmed when the vital signs improve after placement of the needle.
  1. The answer is B, Measure forced vital capacity.
    (Marx, 1413-1415; Wolfson, 790-793)
    The patient in this question is exhibiting symptoms consistent with myasthenic crisis, which occurs in approximately 15% to 20% of patients with myasthenia gravis. She has no acute objective signs of respiratory failure, but her ventilatory status must be evaluated with either a forced vital capacity (FVC) or negative inspiratory force (NIF) measurement. The hallmark of myasthenic crisis is respiratory failure requiring mechanical ventilation, and the mainstay of treatment is airway management with monitoring of ventilatory status for worsening function. Myasthenic crisis can occur without any clear inciting factors, but it can be triggered by infection, fever, or stress or by the addition of a new medication such as muscle relaxants, anesthetics, and certain antibiotics such as the quinolones. Although this patient does not need emergent intubation, the clinical picture can change rapidly. Trending of the patient’s FVC or NIF helps monitor ventilatory effort. Pyridostigmine, an acetylcholinesterase inhibitor, is used as an outpatient treatment for myasthenia gravis. By blocking the degradation of acetylcholine in the synapse, pyridostigmine prolongs acetylcholine activity. Use of pyridostigmine in the acute setting is not recommended because high doses can lead to muscle weakness. A patient in myasthenic crisis is at no higher risk for pulmonary embolism than any other person. Ocular symptoms are a common presentation in new-onset myasthenia and can manifest as diplopia or lid lag, which especially worsens with fatigue. Cold temperatures should improve these symptoms: placing an ice bag over the patient’s eyes should result in a decrease in lid lag 2 minutes later.
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