# # Pediatric Critical Care Review Hasan Pappas

1. Central hypoventilation syndrome is characterized by dysfunction of the respiratory center responsible for autonomic control of breathing. True statements pertaining to this syndrome include all of the following except: A. Apnea occurs typically during REM sleep B. Usually presents with cyanosis at birth that requires positive pressure ventilation C. Diminished school performance, hypersomnolence or morning headache may be the clinical presentation D. Cor pulmonale is a recognized complication E. Acquired causes are well recognized Click here for answer 2. Acquired central hypoventilation syndrome may be due to: A. Posterior fossa tumors B. Brain stem encephalitis C. Severe asphyxia following near-drowning D. Medullary infarction E. All of the above Click here for answer 3. Central hypoventilation syndrome is seen in which of the following conditions: A. Neoplasms of the cerebellum B. Encephalitis C. Idiopathic hypothalamic syndrome D. Pyruvate dehydrogenase deficiency E. All of the above Click here for answer A. Achondroplasia B. Arnold-Chiari malformation C. Both D. Neither 4. ____ When apnea is seen, it is usually mixed apnea ____ Typically causes central apnea Click here for answer 5. The case illustrated above is most compatible with: A. Obstructive apnea B. Central hypoventilation syndrome with central apnea C. Mixed apnea D. None of the above Click here for answer 6. Fortunately, spinal cord injuries are uncommon in children. True statements pertaining to this disorder include all of the following except: A. Lower thoracic and lumbar spine injuries do not produce any abnormalities in respiratory function due to the preservation of diaphragm and intercostal muscles B. Ventilation/perfusion mismatch is a recognized phenomenon with C3-C5 injury C. Hypoventilation is a recognized phenomenon in infants with lesions below C5 D. High cervical spine lesions (C1-C2) result in apnea and early death E. Pulmonary edema is a recognized associated complication Click here for answer 7. Traumatic spinal cord injury should be suspected in a child with: A. Hypotension B. Flaccidity C. Hypoventilation D. Coma E. All of the above Click here for answer 8. A 5-year-old involved in a motor vehicle accident is intubated for hypoventilation. His increased intracranial pressure is controlled with moderate hyperventilation and intravenous mannitol. No seizure activity has been noted. The most appropriate neurodiagnostic test for evaluation of possible spinal cord injury is: A. MRI B. Portable cervical spine radiographs C. Somatosensory evoked potential D. Auditory evoked potential E. None of the above Click here for answer 9. Following spinal cord injury in children, important facts to remember when caring for the patient include all except: A. Radiographic bony abnormality is evident in the vast majority of cases B. Gastric and intestinal motility are depressed C. Suctioning of the trachea may induce bradycardia due to an exaggerated vagal response D. Upper airway occlusion may occur due to asynchronous stimulation of the diaphragm and upper airway E. Pulmonary edema may occur Click here for answer 10. Mortality due to tetanus is most commonly secondary to abnormalities in the: A. Respiratory system B. Cardiovascular system C. Neurologic system D. Immunologic system Click here for answer 11. Tetanus can develop following entry of the organism into the body in which of the following conditions: A. Otitis media B. Intravenous drug abuse C. Contaminated umbilical cord D. Septic abortion E. All of the above Click here for answer 12. Which of the characteristics of tetanus in the newborn is least likely: A. Clinical presentation is usually at the end of the first week B. Poor feeding is an early sign of the disease C. Reflex spasm and rigidity D. Generalized seizures E. Extremely painful muscle spasms are provoked by stimulation Click here for answer 13. Which of the following is true regarding clinical and laboratory features of tetanus: A. Wound cultures reliably and consistently yield the causative organism B. CSF abnormalities are fairly typical C. Leukocytosis is a consistent finding D. Absence of a portal of entry is rarely seen E. None of the above Click here for answer 14. In a patient with tetanus, “respiratory convulsions” A. Often arise unexpectedly B. May lead to severe hypoxia C. Treatment involves rapid administration of a rapidly acting muscle relaxant followed by endotracheal intubation D. Continued muscle relaxation following intubation is advised E. All of the above Click here for answer 15. Characteristics of neonatal tetany include: A. A high predisposition to aspiration pneumonia B. Prolonged nasotracheal intubation compares favorably to tracheostomy C. Infants are particularly prone to laryngeal spasm following extubation D. The need for mechanical ventilatory support for 3-5 weeks E. All of the above Click here for answer A. Poliomyelitis B. Guillain-Barre Syndrome C. Both D. Neither 16. ____ Autonomic nervous system dysfunction is a recognized complication ____ Mortality is largely attributed to the respiratory dysfunction ____ Distal symmetrical weakness in lower extremities is an early sign of the disease ____ Weakness usually progresses over a period of several days Click here for answer 17. A 5-year-old Vietnamese child presents to the emergency department with cyanosis, increased respiratory secretions, and excessive salivation. He is intubated and transferred to the PICU. History reveals that his family moved to the USA about five weeks ago and that he has not received any immunizations. The father indicates that a 7-year-old neighbor died of some unknown respiratory disease in Vietnam about three weeks prior to their departure. The patient has had upper respiratory infection symptoms for 3-4 days, but today he was complaining of shortness of breath and became progressively cyanotic with inability to move his left arm. Physical examination reveals absent DTR in right knee and left elbow. Appropriate statements pertaining to this case is/are: A. The alarming rapidity of progression of the muscle weakness is typical of this condition B. Cerebrospinal fluid pleocytosis with elevated protein may be noted and the causative agent may be isolated from fecal or oropharyngeal specimens C. A clinical picture similar to this may be seen in an immunocompromised patient in the USA D. Survival from this disease is the rule E. All of the above Click here for answer 18. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a recognized complication of which of the following: A. RSV Infection B. Guillain-Barre Syndrome C. Both D. Neither Click here for answer 19. Indications for endotracheal intubation for a child with Guillain-Barre Syndrome include all of the following except: A. Forced vital capacity of < 15 ml/kg B. Maximum inspiratory pressure below –20 cm H2O C. Decreased residual volume D. PaCO2 > 50 torr with acidemia E. Weak cough or gag or the presence of atelectasis Click here for answer 20. When preparing to intubate a patient with Guillain-Barre Syndrome: A. Depolarizing muscle relaxants should be avoided B. Absence of protective airway reflexes is an indication for tracheal intubation C. Circulatory response to intravenous sedatives is exaggerated D. All of the above Click here for answer 21. Regarding mechanical ventilatory support of patients with Guillain-Barre Syndrome, all of the following are true except: A. Pneumonia is an uncommon complication in these patients B. Timely tracheal suctioning and provision of chest physiotherapy is of utmost importance in these patients C. Recovery from the respiratory insufficiency is the rule, despite the presence of residual weakness in 20% of patients D. Initially, total ventilatory support should be provided followed by partial withdrawal slowly Click here for answer 22. The most common form of cardiac rate/rhythm abnormality in Guillain-Barre Syndrome is: A. Sinus tachycardia B. Sinus bradycardia C. Sinus node dysfunction D. Ventricular fibrillation E. Ventricular tachycardia Click here for answer 23. Adults with unilateral diaphragmatic paralysis maintain normal oxygenation in the upright posture despite loss of 25% of vital capacity. Infants on the other hand develop significant gas exchange abnormalities related to: A. The very compliant chest wall of the infant B. Horizontal orientation of the rib cage C. The fact that infants are usually cared for in the supine position D. All of the above Click here for answer 24. The most common cause of a unilateral diaphragmatic paralysis in infants is: A. Trauma from motor vehicle accident B. Trauma from cardiothoracic surgery C. Birth trauma D. None of the above Click here for answer 25. Regarding juvenile myasthenia gravis, all of the following are true except: A. Early symptoms frequently follow an acute viral illness B. Early symptoms predominantly involve cranial nerves C. Hyperthyroidism is a recognized association D. Other autoimmune diseases such as systemic lupus erythematosus are not associated with myasthenia gravis Click here for answer 26. Congenital myasthenia gravis is not characterized by which of the following: A. Onset a few days after life B. History of myasthenia in the mother during pregnancy C. History of myasthenia in a sibling D. Poor feeding E. Respiratory failure is unusual Click here for answer 27. Neonatal myasthenia gravis is characterized by all of the following except: A. Dysphagia and dysphasia within 24 hours after delivery B. Uniformly born to mothers with myasthenia gravis C. Symptoms respond poorly to anticholinesterase therapy D. Symptoms subside by five weeks after birth Click here for answer 28. Familial infantile myasthenia gravis is characterized by: A. Not being born to a mother with myasthenia gravis B. History of myasthenia in a sibling C. Marked respiratory depression to the point of apnea at birth D. Episodes of weakness and apnea in the first two years of life which respond to anticholinesterase therapy E. All of the above Click here for answer 29. A 14-year-old with myasthenia gravis is noted to have stridor following extubation after a surgical removal of a lump in the breast. The stridor in this patient could be due to: A. Vocal cord paralysis B. Laryngeal muscle weakness C. Post-extubation stridor due to glottic/subglottic edema D. All of the above Click here for answer 30. Regarding the need for and necessary precautions for endotracheal intubation in a patient with myasthenia gravis, which of the following statements is most accurate: A. Vocal cord paralysis and laryngeal muscle weakness are recognized causes of airway obstruction following general anesthesia B. Succinylcholine is the agent of choice to facilitate intubation C. Peripheral muscle weakness correlates well with respiratory muscle weakness D. Extubation can be done within a few days in those requiring ventilatory support E. Plasmapheresis has not been shown to decrease the duration of endotracheal intubation and mechanical ventilation post-operatively Click here for answer 31. Which of the following statements is incorrect regarding pathophysiology of botulism: A. The toxin binds to pre-synaptic, pre- and post-ganglionic parasympathetic neurons and at the neuromuscular junction B. The vast majority of cases are associated with ingestion of home-canned food C. Binding of the toxin to the neurons is irreversible D. Level of consciousness is often disturbed E. The need for prolonged ventilatory support is typical Click here for answer 32. Regarding infantile botulism, all of the following are true except: A. Endotracheal intubation is recommended whenever significant depression of gag reflex is noted B. Signs of severe occulomotor nerve dysfunction has been linked to the eventual development of respiratory failure C. Recovery of peripheral muscles is noted before recovery of the diaphragm D. Return of head control can be used in timing of attempts at aggressive weaning and extubation E. Autonomic disturbances such as alteration in heart rate and blood pressure do occur, but do not require any intervention Click here for answer 33. Evoked potentials are tools that are available to neuro-intensive care. Which of the following statement(s) regarding evoked potentials is/are true: A. Evoked potentials are employed primarily as diagnostic and prognostic aids B. With somatosensory evoked potentials, absence of the cortical wave bilaterally in comatose patients is predictive of a vegetative state C. Absence of brainstem auditory evoked potentials in the presence of wave I are highly predictive of brain death D. All of the above Click here for answer 34. Which one of the following statements about traumatic brain injury is least correct: A. The integrity of CO2 vaso-responsivity has prognostic value in that outcome is better in those patients with intact vaso-responsivity B. In severe head injury, vaso-responsivity to CO2 is lost much more than vaso-responsivity to changes in blood pressure C. Low cerebral blood flow in the frontoparietal cortex suggests a poor neurologic outcome D. After head injury, cerebral blood flow may become pressure-dependent Click here for answer 35. Regarding the pathophysiology of meningitis, all of the following are true except: A. Markedly reduced cerebral blood flow is recognized and this is associated with a poor prognosis B. In those patients with normal cerebral blood flow, regional hypoperfusion is common C. Reduced cerebral perfusion pressure, primarily due to increased intracranial pressure which occurs early in the course of meningitis is associated with a poor prognosis D. Auto-regulation is lost E. The reactivity of cerebral blood flow in response to changes in PCO2 is well preserved and raises the possibility that severe hyperventilation may cause further ischemic damage Click here for answer 36. Which of the following would be the most useful technique for prognostication in a setting of head injury: A. Somatosensory evoked potentials B. Visual evoked potentials C. Brainstem audio evoked potentials D. Compressed spectral array (CSA) E. Cerebral function monitor (CFM) Click here for answer 37. The severity of cerebral edema can inherently impact prognosis of brain injury patients. Which one of the following statements regarding cerebral edema is false: A. Vasogenic edema has a better prognosis than cytotoxic edema because neurons are not primarily injured B. Cytotoxic edema involves failure of ATP-ase dependent sodium exchange C. Cerebral blood volume is the important determinant of intracranial pressure D. Cerebral blood flow is the primary determinant of intracranial pressure Click here for answer 38. Which of the following is/are true statements regarding treatment of intracranial pressure: A. Ketamine may cause cerebral vasodilation secondary to a cholinergic mechanism B. PEEP when used at high levels may increase intracranial pressure C. Mannitol may decrease cerebral blood flow via vasoconstriction D. All of the above Click here for answer 39. Select the most accurate events following global cerebral ischemia: A. Ischemia, hyperemia, hypoperfusion B. Ischemia, hypoperfusion, hyperemia C. Ischemia with persistent hyperemia D. Ischemia with persistent hypoperfusion Click here for answer 40. All of the following are true regarding histological changes in the brain following ischemia except: A. Intracellular organic disruption indicates irreversible injury B. Reperfusion may liberate toxic metabolites C. Cellular swelling is seen in the early stages and is reversible D. The most vulnerable area of the cortex are layers 3, 5 and 6 E. CA1 and CA3 sectors of the hippocampus are spared from injury Click here for answer 41. Which one of the following statements is incorrect regarding clinical and imaging evaluation of the central nervous system: A. The CT scan is more sensitive for the detection of acute subarachnoid hemorrhage than the MRI B. The posterior fossa is more clearly visualized by the MRI than CT scan C. The occulomotor nerve can be assessed by the corneal reflex D. Decerebrate posture correlates with high pontine and mid brain lesions Click here for answer 42. Match the pupillary change with the corresponding location of that lesion in the brain: A. Small reactive bilateral B. Unilateral-dilated and fixed C. Large fixed-hippus bilateral D. Pinpoint bilateral E. Midposition-fixed bilateral ____ Pons ____ Midbrain Click here for answer 43. All of the following statements regarding status epilepticus are true except: A. It is defined as epileptic activity lasting longer than 30 minutes without recovery of level of consciousness B. In experimental models, Phase I is characterized by hypertension, lactic acidosis, and hyperglycemia C. Phase I lasts approximately 30 minutes D. Phase II is characterized by hypothermia, hypokalemia, and hyperglycemia E. Cerebral blood flow, glucose and O2 consumption diminish during Phase II Click here for answer 44. Which of the following statements is inaccurate regarding the pharmacology of lipid soluble anticonvulsants: A. A lipid soluble drug possesses a “distribution” phase and an “elimination” phase B. The volume of distribution of a lipid soluble drug is directly proportionate to the degree of its solubility C. With highly lipid soluble drugs, free brain concentration does not correspond to free serum concentration E. Without a loading dose, a time equivalent to 5 or more elimination half-lives is required to attain a steady-state serum concentration Click here for answer 45. Diazepam and lorazepam are commonly used to abort seizures. Which of the following statements most accurately describes these two medications: A. Diazepam is the least lipid soluble of the anticonvulsants B. Lorazepam has more associated side effects of respiratory depression and apnea than diazepam C. Diazepam has a very small volume of distribution due to its poor lipid solubility D. Lorazepam does not have any significant metabolites E. The volume distribution of lorazepam is at least five times that of diazepam Click here for answer 46. Which of the following statements inaccurately describes the pharmacology of anticonvulsants: A. Phenobarbital has a very slow onset of action due to its very low lipid solubility B. Elimination kinetics of phenytoin are linear C. When used repeatedly for status epilepticus, lorazepam may become progressively less effective D. Thiopental and paraldehyde can be used as alternative choices in the treatment of status epilepticus E. Infants have a higher elimination capacity for anticonvulsants than older children Click here for answer 47. Of all trauma admissions involving children, the vast majority are attributable to: A. Head injury B. Chest injury C. Abdominal injury D. Pelvic injury E. Genitourinary injury Click here for answer 48. Which of the following statements is incorrect with regard to mechanisms of brain injury: A. Primary brain injury can occur from direct impact causing neuronal injury or oblique acceleration forces to long white matter tracts resulting in axonal shear injury B. Most gray matter contusions are seen on the inferior aspect of the temporal and frontal lobes C. Diffuse white matter injury is often seen in the areas of the corpus callosum and brainstem D. Cytotoxic edema is more likely to be seen in the white matter, and vasogenic edema in the gray E. Most head injuries in children do not involve a skull fracture Click here for answer 49. Which of the following statements is most accurate regarding glutamic acid in the brain: A. It is released normally in high concentrations from glial cells B. When released from glial cells, it is a source of nutrition for astrocytes C. Its concentration in the brain interstitium is inversely related to intracranial pressure D. It is usually found in negligible concentrations in the brain extracellular fluid Click here for answer 50. A 2-year-old toddler receives 200 mg of phenobarbital intravenously. The patient’s weight is 10 kg and the volume distribution for phenobarbital is 1 L/Kg body weight. The initial blood concentration is expected to be: A. 10 mg/l B. 20 mg/l C. 30 mg/l D. 40 mg/l Click here for answer 51. Which of the following statements below most accurately describes the anatomy and physiology of the brain: A. The majority of the blood flow to the brain is committed to the white matter B. Arterial oxygen tension has no influence on cerebral blood flow C. A change of 1 mm Hg in PaCO2 results in a 4% change in cerebral blood flow D. Water constitutes only 30% of the total white matter and gray matter contents Click here for answer 52. Match the following sign/symptom with the expected location of the lesion in the brain: ____ Nystagmus A. Hypothalamus ____ Tonic deviation of the eye(s) B. Deafferented pupil ____ Marcus Gunn pupil C. Cerebellum ____ Horner’s Syndrome D. Ipsilateral cortex ____ Midposition pupils with hippus E. Midbrain tectum ____ Pinpoint pupils (reactive) F. Pons ____ Leakage of CSF from nose G. Cribiform plate of ethmoid Click here for answer 53. Which of the following cardiorespiratory abnormalities is/are recognized to be associated with head injury: A. Ventricular and supraventricular tachycardia B. Sinus arrest C. Pulmonary edema D. All of the above E. None of the above Click here for answer 54. The above diagram represents the relationship between intracranial volume and the intracranial pressure. Most of the initial compensation that leads to a shift from the position A to B on the curve is due to: A. Compression of lateral ventricles B. Decreased cerebrospinal fluid production C. Egress of cerebrospinal fluid from intracranial to intraspinal space D. Decreased O2 delivery to the brain Click here for answer 55. Match the following central nervous system lesions with the corresponding descriptions below: A. Contusion B. Penetrating injury C. Epidural hematoma D. Subdural hematoma E. Intracerebral hematoma ____ In most cases, treatment is non-operative and outcome is poor ____ Dense crescentic lesion on brain CT scan ____ Localized lenticular lesion on brain CT scan ____ Clostridium perfringes abscess ____ An area of bruising or microscopic hemorrhage caused by trauma ____ May occur secondary to birth trauma Click here for answer 56. A 6-year-old boy has developed a cerebrovascular accident (stroke) involving the distribution of the middle cerebral artery. Which one of the following metabolic disorders is most likely to be the underlying predisposing factor: A. Homocystinuria B. Congenital adrenal hyperplasia C. Phenylketonuria D. Vitamin D deficiency E. Wilson’s Disease Click here for answer 57. A 10-year-old girl presents with a sudden onset of excruciating headache followed by progression to a coma over a very short period of time. Computerized tomography was suggestive of a ruptured arteriovenous malformation with extensive subarachnoid hemorrhage. She was admitted to the Pediatric ICU where she slowly recovered over a period of several days. Now three weeks after discharge from the hospital, she presents with somnolence and papilledema which is detected on physical examination. The most likely explanation for this neurologic deterioration is: A. Arterial spasm B. Astrocytoma C. Communicating hydrocephalus D. Obstructive hydrocephalus E. Pseudotumor cerebri Click here for answer 58. A 5-year-old who has been struck by an automobile while crossing the street has been admitted to the Pediatric ICU. In evaluating this patient, which of the following clinical descriptions is most accurate: A. Cerebrospinal fluid rhinorrhea develops in 70% of cases of basilar skull fracture and is permanent in the vast majority of cases B. Ecchymosis with bluish discoloration in the periorbital area in this patient is referred to as Battle’s sign C. Use of corticosteroids will definitely be beneficial in this patient if significant head injury is suspected D. If a basilar skull fracture is suspected in this patient, radiographic studies will positively identify the fracture site in greater than 90% of cases E. Because of the underdevelopment of sinuses at this age, cerebrospinal fluid rhinorrhea would be rare in this patient Click here for answer 59. Select which of the following requires definitive debridement and elevation within 48 hours: A. Depressed skull fracture B. Linear skull fracture C. Both D. Neither Click here for answer 60. A 3-year-old white male suffers a 2-hour seizure after abruptly losing consciousness while at play. An initial CT scan of his brain reveals a 3 cm aneurysm involving the circle of Willis. Which of the following statements is true regarding cerebral vasculature: A. The posterior circulation (paired vertebral arteries and basilar artery) supplies brainstem and cranial nerves B. The circle of Willis is formed by the internal carotid artery, the middle cerebral arteries, and the anterior and posterior communicating arteries C. Wallenberg’s Syndrome is caused by the compromise of the posterior-inferior cerebellar artery D. Ischemia in the vascular distribution of the superior cerebellar artery will cause dizziness, tremor, and contralateral weakness E. All of the above Click here for answer 61. Match the disease process with its most closely associated finding: ____ Thrombotic stroke A. Rete mirabile of Moyamoya ____ Embolic stroke B. Right to left cardiac shunt ____ Intracerebral hemorrhage C. Arteriovenous malformations Click here for answer 62. Which of the following regarding strokes in children is true: A. Basilar artery migraine is a differential diagnosis B. Exchange transfusion does not help treat a child with stroke and polycythemia C. Hyperventilation improves clinical outcome of ischemic strokes D. Steroid administration improves clinical outcome in stroke patients E. Anticoagulation is indicated in evolving strokes Click here for answer 63. State whether the following statements are true or false regarding arteriovenous malformations in children: ____ A. Single most common causes of cerebral hemorrhage in children ____ B. Vascular resistance is high causing high blood flow ____ C. Most patients remain asymptomatic throughout the adolescent period ____ D. Most common presentation is headache ____ E. The “Gold Standard” test for diagnosis is 4-vessel angiography ____ F. Resection is the procedure of choice Click here for answer 64. All of the following statements are true regarding intracranial aneurysms except: A. Relatively rare in children B. Saccular or “berry” type is the most common C. Mycotic aneurysms are associated with congenital heart disease D. Fusiform aneurysms occur following trauma E. A large majority occur at the posterior and anterior communicating arteries Click here for answer 65. State whether the following statements regarding aneurysms in children are true or false: ____ A. Aneurysms rarely cause seizures ____ B. Vein of Galen aneurysm presents in the neonate with congestive heart failure ____ C. Polycystic kidney disease, aortic coarctation, Marfan’s syndrome and Moyamoya are associated with an increased risk of intracranial aneurysm Click here for answer Answers 1-3. A, E, E With central hypoventilation syndrome, apnea usually occurs during quiet sleep, however, it can happen during rapid eye movement sleep (REM). Included in questions #2 and #3 are some of the reorganized causes of central hypoventilation syndrome. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 235-238) 4. C, D Both achondroplasia and Arnold-Chiari malformation give rise to a mixed type of apnea and neither typically causes central apnea. (Canfield P, et al. Clin Pediatr, 1982; 21:684; Pauli RM, et al. J Pediatr, 1984; 104:342) 5. B The absence of any chest wall movement is highly suggestive of a central apnea. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 235-238) 6. A There will be some abnormalities in the respiratory function due to the loss of abdominal muscle activity and loss of their participation in the respiratory effort. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 239-241) 7. E The hypotension is typically associated with bradycardia and may be very difficult to manage. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 239-241) 8. C Somatosensory evoked potentials detect brain wave activities in response to peripheral nerve stimulation, and therefore, it evaluates the entire neuronal track from the cortex down to the peripheral nerve. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 693-694; Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 604) 9. A Spinal cord injury without any significant radiographic abnormalities is commonly seen in the pediatric population. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 239-241) 10-15. A, E, D, E, E, E Various portals of entry of the organism into the body are recognized. In 20% of cases, a portal of entry is not found based on history and physical examination, and therefore, absence of the portal of entry is not very rare. Also of note, is that cultures may not reveal the causative organism. Generalized seizures are not a recognized feature of tetanus, however, the so-called “respiratory convulsions” can develop and require immediate attention to opening and maintaining the airway which often includes endotracheal intubation. The mortality due to tetanus is most commonly secondary to respiratory abnormalities. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 241-244) 16. C, C, B, B Autonomic dysfunction is a recognized feature of both poliomyelitis and Guillain-Barre Syndrome, and the mortality in both is due to respiratory dysfunction. Poliomyelitis generally presents with asymmetric scattered weakness, as opposed to the symmetric weakness that is noted with Guillain-Barre Syndrome, and the clinical progression is usually rapid with poliomyelitis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 242-246; Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 638) 17. E All of the features mentioned are correct, and this is a case of poliomyelitis which is very rare in the US, however, it is still seen in developing countries and can certainly be imported into the US. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 242-244) 18. C SIADH occurs with both Respiratory Syncytial Virus (RSV) infection and Guillain-Barre Syndrome. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 132, 244-246; Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 638) 19. C Residual volume is not clinically useful in this setting. The two most commonly used parameters for monitoring of patients with neuromuscular disease who might require tracheal intubation or liberation from mechanical ventilation are forced vital capacity (FVC) and maximum or negative inspiratory force (NIF). (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 245-247; Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 426) 20. D In patients with neuromuscular disease, depolarizing muscle relaxants such as succinyl choline should be avoided because of the possibility of cardiac dysrhythmias and sedatives should be used very cautiously. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 239-247; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 1341-1345) 21-22. A, A Pneumonia is a common complication in patients with Guillain-Barre Syndrome. Among the options, sinus tachycardia is the most common abnormality in these patients. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 244-246; Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 638) 23-24. D, B Diaphragmatic paralysis secondary to a phrenic nerve injury most commonly follows a palliative repair of a congenital cardiac defect such as a Blalock-Taussig shunt. In infants and children, this entity is much more likely to lead to gas exchange abnormalities and could be analogous to a flail chest in an adult. This arises because of the highly compliant chest wall and poor ability of the intercostal muscle to stabilize the chest wall. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; 247-249; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 360-361) 25-29. D, B, C, E, D There are various subtypes of myasthenia gravis. Juvenile myasthenia gravis is usually seen in teenage years. Onset of symptoms often follows a viral respiratory infection and cranial nerves, particularly extraocular movements are predominantly involved. Other autoimmune diseases such as systemic lupus erythematosus or thyroid disorders may be associated. Congenital myasthenia gravis: has an onset a few days after birth with poor feeding and respiratory difficulty/failure. Family history is often present in sibling, but history of myasthenia in the mother during pregnancy is absent. Neonatal myasthenia gravis: are uniformly born to mothers with myasthenia gravis; 1/5 a transient in nature (as the autoantibodies resolve) and responds well to anticholinesterase medications. Familial infantile myasthenia gravis: is usually not born to mothers with myasthenia gravis even though there is often history of myasthenia gravis in a sibling. These patients develop marked respiratory depression and require tracheal intubation. The subsequent clinical course is characterized by episodes of muscle weakness in the first 2 years of life, which may progress to respiratory failure. Episodes do respond to anticholinesterase therapy. Following general anesthesia with tracheal intubation, patients with myasthenia gravis may develop stridor with or without respiratory distress secondary to the following factors: glottic/subglottic edema due to traumatic intubation, laryngeal muscle weakness or vocal cord paralysis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 249-251) 30. A Succinylcholine, in general, should be avoided in patients with neuromuscular disease. Peripheral muscle weakness does not seem to correlate well with respiratory muscle weakness. Plasmapheresis has been shown to decrease the duration of endotracheal intubation and mechanical ventilatory support post-operatively in patients with myasthenia gravis. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 249-251) 31. D The level of consciousness is typically preserved in patients with infantile botulism. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 251-253; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 639-640) 32. C Recovery of the diaphragm seems to occur prior to recovery of peripheral muscles. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 251-253) 33. D All of the statements regarding evoked potentials are true. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 690-696; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 604, 682) 34. B In severe head injury, the vaso-responsivity to changes in blood pressure is lost earlier than that in response to CO2. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 649-652) 35. D In meningitis, the autoregulation to cerebral blood flow seems to be intact. (Ashwal S, et al. J Pediatr, 1990; 117:523-530) 36. A In a patient with head injury and coma, absence of cortical waves bilaterally with the somatosensory evoked potentials is associated with poor outcome. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 694-695; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 604, 682) 37. D Cerebral blood volume is an important determinant of intracranial pressure. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 648-650) 38. D All of the statements are true. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 648-650) 39. A The characteristics/pattern of cerebral ischemia is: ischemia, reactive hyperemia, followed by delayed hypoperfusion. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; p 701; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 671-687) 40. E Layers CA1 and CA3 of the hippocampus are one of the most vulnerable areas of the brain to ischemia; others include the cerebellum and layers 3, 5 and 6 of the cerebral cortex. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 701-702; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 671-687) 41-42. C / D, E The corneal reflex tests cranial nerves 5 and 7. Midbrain lesions induce a midsize minimally reactive pupil, while Pontine lesions induce a pinpoint pupil. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 739-744) 43. D In experimentally induced status epilepticus which is divided into Phase I and Phase II, it has been shown that Phase I is characterized by hypertension, lactic acidosis, hyperglycemia and hyper or normokalemia, whereas Phase II is characterized by hypoglycemia, hyperkalemia, hyperthermia, and respiratory compromise. (Lothman E. The biochemical basis and pathophysiology of status epilepticus. Neurology 1990; 40(52):13). 44. C With highly lipid soluble drugs, free brain concentration does correlate with free serum concentration of the drug. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 765-768) 45. D Diazepam is one of the most lipid soluble of anticonvulsants, and therefore, it has a very large volume of distribution due to its high lipid solubility. The volume of distribution of diazepam is at least 5 times that of lorazepam and diazepam has significant metabolites which tend to accumulate and contribute to the prolonged or delayed effects. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 766-767; Fuhrman BP. Pediatric Critical Care, 2nd Edition; pp 629-630) 46. B Phenobarbital does have a low lipid solubility and this accounts for the very slow onset of action. The pharmacokinetics of phenytoin is non linear and this accounts for a significant increase in toxicity at increasingly higher doses. Infants do have a higher elimination capacity for anticonvulsants compared to older children and adults. Lorazepam, when used repeatedly over a period of 48 hours for status epilepticus may become progressively less effective due to development of tolerance. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 767-769) 47. A (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 810-811) 48. D Cytotoxic edema involves primarily the cells, and therefore, is seen primarily in the gray matter. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 647-648) 49. D Glutamic acid is normally found in very small concentrations in the brain interstitial fluid. When it is released from the cell in high concentrations, it is very cytotoxic to glial cells, and also contributes to increased intracranial pressure. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 705-706) 50. B Initial concentration of a drug is equal to the dose administered divided by its volume of distribution. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 766-768) 51. C The majority of blood flow to the brain is committed to the gray matter which contains the cells. Arterial oxygen tension does have a significant influence on the cerebral blood flow. Water constitutes about 65% of total brain content. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 648-650) 52. C, D, B, A, E, F, G (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 737-744) 53. E All have been recognized and associated with head injury. Other abnormalities include ST segmented T-wave changes on the EKG. (Rogers MC, et al. Critical Care Medicine, 1980; 8:213-214) 54. C Some of the initial compensatory mechanisms in response to increased intracranial volume are due to displacement of the spinal fluid from the intracranial to intraspinal space. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 646-660) 55. E, D, C, B, A, E (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 817-834) 56. A Homocystinuria is the metabolic abnormality that is most likely to be associated with the development of stroke. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 868-869) 57. C This patient apparently developed communicating hydrocephalus most likely as a result of blockage of the arachnoid villi within the dural sinuses, the site of drainage for of cerebrospinal fluid back to the venous circulation. (Fuhrman BP. Pediatric Critical Care, 2nd Edition; p 658) 58. E Cerebrospinal fluid rhinorrhea is seen in approximately 7% of basilar skull fractures and the in the vast majority of cases it resolves within a period of a few weeks. Ecchymosis in the periorbital area is referred to as racoon’s eye. Corticosteroids have not been shown to be definitely beneficial in a setting of closed head injury. Cerebrospinal fluid rhinorrhea is uncommon in children less than 10 years of age due to underdevelopment of sinuses. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 816-817) 59. A A significantly depressed skull fracture requires surgical intervention. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; p 855) 60. E All of the statements are true regarding cerebral circulation. (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872) 61. A, B, C (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872) 62. A (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872) 63. T, F, T, F, T, T (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872) 64. D (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872) 65. T, T, T (Rogers MC, et al. Textbook of Pediatric Intensive Care, 3rd Edition; pp 859-872)