e106 SECTION XV Pediatric Critical Care Board Review Questions followed by a taper over several weeks Although prophylactic antibiotics such as acyclovir, ceftriaxone, vancomycin, or metroni dazole ar[.]
e106 S E C T I O N XV Pediatric Critical Care: Board Review Questions followed by a taper over several weeks Although prophylactic antibiotics such as acyclovir, ceftriaxone, vancomycin, or metronidazole are often administered while awaiting the results of cultures and ancillary studies, the child in this scenario is most likely to benefit from treatment with methylprednisolone A 1-year-old child is admitted to the pediatric intensive care unit with signs and symptoms of meningitis Dexamethasone has been shown to improve survival in meningitis because of which of the following etiologic agents? A Drug-resistant pneumococcus B Herpesvirus C Mycobacterium tuberculosis D Neisseria meningitidis Preferred response: C Rationale Meta-analysis and retrospective studies have demonstrated beneficial effects in Hemophilus influenzae type b and pneumococcal meningitis However, this conclusion was made at a time when drug-resistant Streptococcus pneumoniae was not a serious problem The data could support a beneficial effect in H influenzae type b meningitis, but because this organism is an uncommon pathogen at this time, empiric therapy would not be warranted in most cases In the era of drug-resistant S pneumoniae, where an isolate may be resistant to the third-generation cephalosporins, it has been suggested that dexamethasone (DXM) may impair the diffusion of vancomycin through the blood-brain barrier, delaying cerebrospinal fluid sterilization Thus caution has merit Some clinicians recommend the addition of rifampin under these circumstances Further studies are needed in this patient population Lastly, because maximal beneficial effect would be gained by administering DXM prior to antibiotic therapy, previously treated infants and children should not receive DXM No evidence exists that corticosteroids are beneficial in patients with viral or meningococcal or neonatal meningitis In contrast, patients with tuberculous meningitis treated with steroids have an improved survival compared with nonrecipients However, the severity of disability commonly observed with tuberculous meningitis is not altered Which of the following results of a cerebrospinal fluid (CSF) examination is affected the most with the prior use of oral antibiotics? A CSF glucose level B CSF protein level C Gram stain D Neutrophil count Preferred response: C Rationale In most instances, prior oral antimicrobial therapy will not significantly alter CSF cell counts, differential, and chemistries in children with bacterial meningitis In contrast, Gram stain and culture positivity are greatly reduced 8 A 3-year-old child presents to the hospital in July with seizures, fever, meningeal signs, cranial nerve involvement, and speech impairment Cerebrospinal fluid analysis is suspect for a viral etiology Which of the following is the most likely agent of this child’s meningoencephalitis? A Arbovirus B Epstein-Barr virus C Herpesvirus D Varicella-zoster Preferred response: A Rationale The enteroviruses and arboviruses in particular display seasonality in infection and are seen most frequently in the summer and autumn months Herpesviruses, cytomegalovirus, varicella-zoster, and Epstein-Barr virus often show a predilection for the winter and spring Herpes simplex, however, does not demonstrate any seasonality With this epidemiology in mind, the evaluation of children with suspected viral meningoencephalitis is guided by many factors including age, geographic location, season of the year, vaccination status, chronic conditions or immunosuppression, history of tick or mosquito exposure, and travel history Which of the following is the most common presentation of herpesvirus (HSV) encephalitis in a newborn? A Fever B Nuchal rigidity C Seizures D Skin lesions Preferred response: C Rationale Neonates presenting with encephalitis due to HSV often not demonstrate fever The most common presenting signs for neonates with HSV central nervous system disease are seizures and lethargy Skin lesion findings are variable Infants with HSV infection also may have disseminated disease, which increases the morbidity and mortality significantly 10 A 9-year-old boy and his 12-year-old cousin present with similar signs and symptoms of sore throat, headache, nausea, and vomiting a few days after swimming in a lake in Texas On physical examination, both children are irritable and have meningeal signs and ataxia Which of the following is the most likely etiologic agent in these cases? A Herpes simplex virus type B Mycobacterium tuberculosis C Naegleria fowleri D Toxoplasma gondii Preferred response: C Rationale Primary amebic meningoencephalitis (PAM) is a rare, often fatal disease caused by infection with N fowleri, a thermophilic, freeliving ameba found in freshwater environments N fowleri is the causal agent of most PAM infections, but other species of Naegleria having pathogenic potential have been described (Naegleria australiensis and Naegleria italica) The habitat for N fowleri is natural or man-made freshwater lakes or an inadequately chlorinated swimming pool where the amebas can feed on bacteria and proliferate In the United States, N fowleri is commonly found in warm freshwater environments in 15 southern-tier states (Arizona, Arkansas, California, Florida, Georgia, Louisiana, CHAPTER 136 Board Review Questions Mississippi, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, South Carolina, Texas, and Virginia) The onset of PAM is abrupt, with sore throat, headache, nausea, vomiting, malaise, and fever Early findings also may include irritability, hallucinations, meningismus, cerebellar ataxia, and cranial nerve palsies, although focal neurologic defects are usually absent Alterations in taste and smell may occur, likely because of involvement of the olfactory nerve Symptoms begin after a 3- to 7-day incubation period PAM presents in a manner similar to acute bacterial meningitis, but physicians often miss the diagnosis initially History is vital for making the diagnosis Residence or travel to a southern-tier state in the United States must be verified Recent exposure to diving, swimming, or splashing in warm freshwater should suggest the possibility of amebic meningoencephalitis and prompt examination of the CSF for N fowleri Differential diagnosis includes acute bacterial meningitis, herpes simplex virus-1 encephalitis, and viral or fungal meningitis With immunosuppressed patients, amebic meningitis might be confused with toxoplasmosis, cytomegalovirus infection, and other opportunistic pathogens The diagnosis is made by examination of CSF wet mounts for motile trophozoites; however, failure to visualize these amebas does not exclude PAM The diagnosis is often missed when Naegleria organisms are mistaken for atypical monocytes or lymphocytes 11 A 12-year-old is admitted to the pediatric intensive care unit with a history of fever, headache, vomiting, and diplopia Initial evaluation includes magnetic resonance imaging of the brain; a representative image is shown below in Fig 136.21 • Fig 136.21 Which of the following risk factors should be evaluated when assessing patients with this condition? A Acute kidney injury B Cardiac defects C Coagulation defects D Liver dysfunction E Reactive airway disease Preferred response: B e107 Rationale Brain abscesses are often associated with other medical conditions Common factors include associated infections of the sinopulmonary tract, poor dentition, and trauma as well as status post neurosurgical procedure Presence of heart disease significantly increases the risk of brain abscess formation Evaluation reveals presence of cardiac defects in up to one-third of patients with a brain abscess Chapter 68: Acute Neuromuscular Disease and Disorders A 16-year old previously healthy girl is admitted to the PICU with generalized weakness and respiratory insufficiency Over the previous week, she complained of abdominal pain and hearing voices On exam, she is afebrile, exhibits mild tachypnea with shallow breathing, has a supple neck, and an unremarkable abdominal exam On neurological examination, she has some weak phonation, generalized weakness (upper extremity greater than lower extremity), trace reflexes in all four extremities, and absent response to pinprick in distal extremities The following laboratory values are normal: white blood cell count, electrolyte panel, serum glucose, liver function tests, and ammonia Which of the following is the most appropriate initial treatment while awaiting further test results? A Carbohydrate loading B Intravenous fluid resuscitation C Intravenous haloperidol D Intravenous lorazepam Preferred response: A Rationale The patient’s weakness plus abdominal pain and psychiatric symptoms are strongly suggestive of porphyria While waiting for confirmatory urine alpha aminolevulinic acid and urine porphobilinogen levels, carbohydrate loading (enterally preferred, at least 50–60% of caloric needs) may provide some initial benefit The most common of the four types of porphyria is acute intermittent porphyria (AIP) Clinical symptoms in acute attacks span multiple medical subspecialties and may be precipitated by numerous medications, hormonal variations, caloric restriction, and alcohol AIP most commonly occurs in females with the age of onset between 15 and 40 years and rarely occurs before puberty An acute neuropathy is found in approximately 40% of acute AIP attacks The neuropathy typically follows the onset of the attack by one to four weeks but may so as late as 11 weeks Although paresthesias and distal sensory changes may be a prodromal finding, the motor signs are much more prominent Classically, the patient has symmetrical upper extremity proximal weakness, but it may advance to involve the lower extremities Generalized weakness is documented in approximately 42% of patients In AIP’s most dramatic setting, the patient can have a rapid progression of weakness that leads to a flaccid involvement of all four extremities and respiratory compromise When cranial nerves are involved, VII and X are the most frequently affected Ocular vascular compromise has been documented in individuals with vision loss, which may be monocular or total Although this vision loss is usually transient, it can be permanent AIP is often difficult to diagnose The chief complaints are typically nonspecific abdominal and back pain This colicky abdominal pain often leads to the consideration of surgical intervention Notably, AIP is not associated with temperature elevation, e108 S E C T I O N XV Pediatric Critical Care: Board Review Questions leukocytosis, or rebound tenderness Neurological and psychiatric symptoms often accompany the onset of attack Of note, many antiepileptic medications can worsen or induce an attack Worsening has been reported with phenytoin, carbamazepine, phenobarbital, valproate, lamotrigine and potentially tiagabine, and topiramate Gabapentin and levetiracetam have been successfully used Which of the following neuromuscular diagnoses is best treated with gene therapy? A Acute intermittent porphyria B Congenital myasthenia gravis C Normokalemic periodic paralysis D Spinal muscular atrophy Preferred response: D Rationale Spinal muscular atrophy has multiple forms of gene therapy with different targets approved by the FDA for treatment Some children with type I spinal muscular atrophy have even walked after treatment A 4-year old previously healthy girl is admitted to the PICU with respiratory insufficiency following upper respiratory infection Her tonsils appear to have a thick gray covering Which is the most likely cause of mortality in these cases? A Autonomic instability B Disseminated intravascular coagulation C Respiratory failure D Toxic cardiomyopathy Preferred response: D Rationale The thick gray covering on the tonsils of a patient with respiratory failure after upper respiratory infection suggests diphtheria This covering may extend down the airway into smaller bronchi, leading to the respiratory failure However, toxic cardiomyopathy occurs in 10% to 25% of patients and may cause 50% to 60% of deaths This condition may arise in the second to third week of illness when the patient may appear to be improving clinically The diphtheria toxin may affect the myocardium, the conductive system, and the pericardium A 10-year-old boy presents to the hospital after weeks of progressive symmetric leg weakness, which is better in the morning and worsens throughout the day, accompanied by bilateral ptosis The emergency room finds him to have rapid, shallow breathing and absent reflexes After he walks, he becomes too weak to climb back into his hospital bed After stabilizing his respiratory status, which is the most appropriate next step: A AChR antibody testing before treating B Edrophonium challenge C Intravenous immunoglobulin D MRI spine Preferred response: B Rationale The patient clinically appears to have myasthenia based on the ptosis, easily fatigable weakness, and rapid and shallow breathing An edrophonium challenge can quickly confirm the diagnosis Although some patients with mild symptoms may have antibody testing as part of their diagnostic workup before treatment, this patient’s clinical status is too severe to withhold treatment pending those results After an edrophonium challenge, treatment can begin MRI of the spine would not explain the ptosis A 6-month-old baby presents to the emergency room after progressive descending weakness The parents feel the baby developed constipation a couple of weeks ago You notice decreased respiratory drive, weak cry, profound hypotonia and weakness, and absent reflexes The child has no history of fever or other signs of illness Nerve conduction testing and EMG are not readily available Besides supportive care, what is the next most appropriate step? A Administer human botulism immune globulin before confirmatory testing B Begin intravenous immunoglobulin; no confirmatory test is needed C Order stool culture for botulism and await results before further treatment D Start plasmapheresis Preferred response: A Rationale This patient’s history and physical strongly suggest botulism A stool culture may show botulism, but, because of the constipation, the test results may take too long to come back to be helpful The test may still be helpful to confirm but should not delay treatment Human botulism immune globulin has been shown to speed improvement and lead to shorter hospital stays This has not been shown with IVIG An infant presents to the pediatric intensive care unit (PICU) with hypotonia, poor suck, hypoventilation, and impaired swallowing Subsequently the child is diagnosed with botulism A culture of a catheterized urine specimen indicates growth of a gram-negative rod at 106 colonies per mL of urine In addition, a ventilator-associated pneumonia involving a gram-positive coccus in clusters and abundant neutrophils obtained from a protected bronchial brush specimen is diagnosed In this setting, which of the following antimicrobial agents specifically should be avoided? A Ampicillin B Azithromycin C Cefuroxime D Gentamicin Preferred response: D Rationale Aminoglycosides will exacerbate any neuromuscular blockade and their use should be avoided in persons with botulism Which of the following statements concerning Guillain-Barré syndrome (GBS) is true? A Cerebrospinal fluid (CSF) findings in the first week include decreased levels of protein B GBS typically presents with a progressive paralysis limited to the lower extremities C Sphincter disturbances occur frequently in the course of GBS D Steroids not help hasten the recovery of persons with GBS Preferred response: D CHAPTER 136 Board Review Questions Rationale The neurologic symptoms of GBS typically present with progressive paralysis that is relatively symmetrical and may evolve to all extremities Other symptoms include varying degrees of hyporeflexia or areflexia, or even respiratory embarrassment Other presentations include acute ataxia, pain, or cranial neuropathies In one study, risk factors for patients requiring ventilation included cranial nerve involvement, elevated CSF protein during the first week of illness, and a short period between antecedent illness and onset of symptoms Sphincter disturbances rarely occur early in the course of GBS and are usually transient Autonomic symptoms that may be overlooked also are present in some cases Autonomic instability, particularly cardiac arrhythmias, increases the morbidity of this disease Per criteria established by Asbury and Cornblath, the features that are required for the diagnosis include progressive motor weakness of more than one limb and areflexia Symptoms that are strongly supportive of GBS include the relative symmetry of symptoms, mild sensory symptoms, cranial nerve involvement, autonomic symptoms, and recovery that usually begins to weeks after symptom progression discontinues Steroids not help hasten the recovery of persons with GBS If the symptoms are severe, treatment options for GBS include plasmapheresis and intravenous immunoglobulin (IVIG) In 2003 the American Academy of Neurology published a practice parameter after reviewing the adult literature and made several recommendations First, plasmapheresis and IVIG both hasten recovery, and neither is more efficacious Using these two treatments sequentially is not superior to use of either treatment alone Which of the following findings are a part of the criteria for the diagnosis of dermatomyositis? A Decrease of aldolase B Decreased and low frequency discharges on an electromyogram C Heliotrope rash D Symmetrical distal weakness Preferred response: C Rationale Five major criteria are described for the diagnosis of dermatomyositis: (1) symmetrical proximal weakness is present, which may include respiratory muscles; (2) the dermatological criterion includes the heliotrope rash and Gottron’s sign in addition to a scaly erythematous rash over the joints, face, neck, and upper torso; (3) elevated creatine phosphokinase and aldolase are laboratory criteria; (4) muscle biopsy discloses evidence of necrosis of type I and II fibers, phagocytosis, and inflammatory exudates; and (5) the electromyographic criteria in dermatomyositis are consistent with an inflammatory myopathy revealing spontaneous activity, myopathic motor units, and bizarre high-frequency repetitive discharges Which of the following is the most common cause of acute flaccid paralysis in children? A Botulism B Guillain-Barre syndrome C Myasthenia gravis D Tick paralysis Preferred response: B e109 Rationale Guillain-Barre syndrome (GBS) is the most common cause of acute flaccid paralysis in children The incidence is estimated to be 0.38 to 1.1 per 100,000 in a population younger than 15 years Other causes of acute flaccid paralysis in the pediatric population include botulism, tick paralysis, periodic paralyses, and organophosphate poisoning 10 A 3-year-old child presents to the PICU with a 1-week history of inactivity and bilateral lower extremity weakness accompanied by numbness Three weeks prior to these symptoms, he had gastroenteritis that has since resolved On physical examination, you notice absence of reflexes in lower extremities and a weak gag reflex The patient looks lethargic You perform a spinal tap Which of the following is the MOST LIKELY result of the spinal tap? A Albuminocytologic dissociation B Decrease in glucose in CSF C Lymphocytosis in CSF D Presence of Gram-negative bacteria on Gram stain Preferred response: A Rationale The most common acute neuromuscular disease to present to the intensive care unit is Guillain-Barre syndrome (GBS) When given the history of an ascending paralysis, a clinician can easily place GBS in the differential diagnosis; however, this history may be difficult to obtain, particularly if the patient is a small child or an infant A prodromal respiratory or gastrointestinal illness is commonly found in the history The prodromal illnesses may include Campylobacter jejuni and cytomegalovirus The neurologic symptoms typically present with progressive paralysis that is relatively symmetrical and may evolve to all extremities Other symptoms include varying degrees of hyporeflexia or areflexia or even respiratory embarrassment Other presentations may include acute ataxia, pain, or cranial neuropathies In one study, risk factors for patients requiring ventilation included cranial nerve involvement, elevated CSF protein during the first week of illness, and a short period between antecedent illness and onset of symptoms Diagnostic studies include examination of the CSF and nerve conduction studies The CSF reveals an elevated protein level amid a relative paucity of white blood cells, usually less than 10 cells/mL, with the protein increasing after the first week of symptoms Electrodiagnostic testing reveals motor conduction velocities in the demyelinating range, conduction block, temporal dispersion, and prolonged F waves 11 The child described in the scenario for Question 10 becomes progressively weaker, requiring endotracheal intubation and mechanical ventilation After days on mechanical ventilation, the child continues to require ventilatory support, and autonomic instability with hypotension and cardiac arrhythmias has developed Besides monitoring and support in the PICU, which other modality of treatment should be initiated in this case? A Extracorporeal membrane oxygenation B Intravenous immunoglobulin C Leukapheresis D Systemic corticosteroids Preferred response: B e110 S E C T I O N XV Pediatric Critical Care: Board Review Questions Rationale If the symptoms are severe, treatment options for GBS include plasmapheresis and intravenous immunoglobulin (IVIG) In 2003 the American Academy of Neurology published a practice parameter after reviewing the adult literature and made several recommendations First, plasmapheresis and IVIG both hasten recovery, and neither is more efficacious Using these two treatments sequentially is not superior to use of either treatment alone Finally, steroids not seem to help The decision of which therapy to apply to children is controversial because a large randomized study has not been performed Plasmapheresis may be technically difficult to perform in young or very small children; therefore, immunoglobulin may be used with more ease Results from one adult study in which the two methods were compared showed that 53% of the patients treated with immunoglobulin improved by one or more grades on the functional scale at weeks compared with 34% of the patients treated with plasmapheresis Favorable improvement in pediatric patients treated with immunoglobulin has been reported in several small series More recently, a randomized trial in children showed that fewer relapses occurred if g/kg of IVIG were divided over days instead of days If additional courses of IVIG are necessary, a 2-day protocol is often well tolerated 12 A previously healthy 8-year-old boy presents to the emergency department in May with complaints of acute onset of weakness in his arms and legs over the previous day and sensation of “pins and needles” in his legs He is unable to get up without assistance The patient is alert, has normal vital signs, and is afebrile Neurologic examination detects the inability to lift his head from the supine position, decreased muscle strength, and absent muscle stretch reflexes in upper and lower extremities, bilateral ptosis, and lateral rectus muscle paresis Findings of an erythrocyte sedimentation rate and cerebrospinal fluid (CSF) examination were normal What is your presumed diagnosis? A Botulism B Guillain-Barre syndrome C Myasthenia gravis D Tick paralysis Preferred response: D Rationale The clinician must always entertain tick paralysis in the differential diagnosis of acute flaccid paralysis in children Affected patients are usually between the ages of and years A female preponderance exists (76%), presumably because of a longer hairstyle among girls The ticks most often implicated in North America are Dermatocentor andersoni (wood tick) and Dermatocentor variabilis (dog tick) Cases in North America typically occur from April to June, when the adult ticks emerge from hibernation to seek hosts The cause of the symptoms is a neurotoxin that is secreted in the saliva of the gravid female tick This neurotoxin inhibits the release of acetylcholine at the presynaptic terminal The symptoms begin with vague complaints of fatigue, irritability, and pain Vague symptoms may not begin until approximately days after tick attachment, but they progress rapidly Other symptoms include ataxia If the tick remains attached, a symmetrical ascending paralysis with areflexia develops Subsequently, cranial nerve symptoms of bulbar and facial weakness and respiratory involvement occur No systemic features are seen in tick paralysis Patients are afebrile with normal vital signs, erythrocyte sedimentation rate, CSF, and mental status The removal of the tick results in the rapid reversal of symptoms, usually within 24 hours 13 What is the correct statement regarding response to therapy in the patient described in the previous scenario? A Anticholinesterase medications are the mainstay of therapy B Intravenous immunoglobulin (IVIG) should be initiated immediately C Plasmapheresis is the preferred modality of treatment D Removal of the tick should result in rapid reversal of symptoms Preferred response: D Rationale In a patient with tick paralysis, removal of the tick should result in rapid reversal of symptoms, usually within 24 hours Removal of the tick is performed with blunt curved forceps or tweezers The tick should be grasped at the point of attachment, as close to the skin as possible The tick should be pulled upward with steady pressure Twisting or jerking motions may cause parts of the tick to break off, particularly the mouth parts The tick should not be handled with bare hands Needham evaluated various methods of tick removal including fingernail polish, petroleum jelly, 70% isopropyl alcohol, and a hot kitchen match None of these passive techniques induced tick detachment Anticholinesterase medications such as pyridostigmine bromide (Mestinon) are utilized for treatment of myasthenia gravis (MG) Plasmapheresis and IVIG play a role in the treatment of myasthenic crisis and acute exacerbations of myasthenic symptoms, as well as more severe cases of GBS with autonomic manifestations 14 What adverse effects should you monitor for during an edrophonium challenge in a patient with myasthenia gravis (MG)? A Bradycardia and bronchospasm B Hypertension and bradycardia C Hypotension and increased fatigability D Tachycardia and hypertension Preferred response: A Rationale When a patient is suspected to have MG, the best diagnostic bedside test is the edrophonium (Tensilon) challenge Edrophonium is an intravenous short-acting anticholinesterase preparation The dosing in infants is 0.15 mg/kg, and the dosing is 0.2 mg/kg in older children Only 10% of the entire dose is given initially so the clinician can observe for muscarinic adverse effects Atropine (0.015 to 0.04 mg/kg) should be available for these possible adverse effects, which include bradycardia and respiratory distress resulting from bronchial secretions and bronchospasm After the trial dose is tolerated, the entire dose is then given The patient should be observed during the trial for changes in ptosis or fatigability The onset of action is approximately 30 to 90 seconds after intravenous push and remains for approximately minutes ... total Although this vision loss is usually transient, it can be permanent AIP is often difficult to diagnose The chief complaints are typically nonspecific abdominal and back pain This colicky... Preferred response: D Rationale The thick gray covering on the tonsils of a patient with respiratory failure after upper respiratory infection suggests diphtheria This covering may extend down the... cardiomyopathy occurs in 10% to 25% of patients and may cause 50% to 60% of deaths This condition may arise in the second to third week of illness when the patient may appear to be improving clinically