e171CHAPTER 136 Board Review Questions 4 A previously healthy, immunized, 12 year old male is admit ted to the PICU For 5 days he has had fever, fatigue, and headache and has had vomiting and lethargy[.]
CHAPTER 136 Board Review Questions A previously healthy, immunized, 12-year-old male is admitted to the PICU For days he has had fever, fatigue, and headache and has had vomiting and lethargy for days On the day of admission he had a 1-minute focal tonic-clonic seizure History is remarkable for a recent summer vacation trip to the northeastern United States where he spent a significant time outside and had many mosquito bites Examination reveals fever, somnolence, nuchal rigidity, and a faint maculopapular rash on the trunk and extremities Lumbar puncture reveals 40 white blood cells with 90% lymphocytes; protein, 75 mg/dL; and glucose, 60 mg/dL Cerebrospinal fluid (CSF) Gram stain is negative Enterovirus and herpes simplex virus (HSV) polymerase chain reaction (PCR) from the CSF are also negative Which of the following tests is most likely to reveal the diagnosis? A Acute and convalescent West Nile virus IgG and IgM from serum B Adenovirus PCR of the CSF C Rabies virus immunofluorescent microscopy from a skin biopsy D Measles virus IgG and IgM from serum Preferred response: A Rationale This patient has West Nile (WN) meningoencephalitis WN virus is an arbovirus transmitted by mosquitoes and generally has a seasonal distribution in the summer Rash is a common feature but not necessary Aseptic meningitis, encephalitis, and acute flaccid paralysis are among the neurologic complications of West Nile infection HSV and enterovirus encephalitis are less likely in a patient with negative CSF PCRs Rabies virus encephalitis is rare but should be considered in the differential diagnosis of acute encephalitis Measles encephalitis is unlikely in the setting of an immunized child, especially without cough and conjunctivitis Finally, adenovirus rarely causes meningoencephalitis CSF viral culture is not a sensitive method of diagnosis If herpes simplex virus (HSV) encephalitis or neonatal disease is suspected, the most important initial step is to which of the following? A Determine the source of the exposure B Initiate empiric treatment with intravenous acyclovir C Initiate appropriate infection control precautions D Obtain diagnostic specimens including cerebrospinal fluid for HSV polymerase chain reaction Preferred response: B Rationale When it is untreated, HSV encephalitis carries a death rate in excess of 70%, and even when it is treated, death and complications for those who survive remain on the order of 15% and 20%, respectively Similarly, despite treatment, neonatal HSV central nervous system disease carries a significant risk of death and morbidity, ranging from 0% to 15% and 43% to 68%, respectively Early identification of patients and rapid initiation of acyclovir have been associated with a better outcome Unless an alternative cause is clear, high-dose acyclovir should be initiated in all children with encephalitis until HSV can be ruled out e171 Chapter 109: Healthcare-Associated Infections The single most important risk factor for development of healthcare-associated infections (HAIs) is: A Having a weakened or immature immune system B Having already contracted one or more HAIs during a hospitalization C Improper hand washing or failing to perform hand hygiene D Inconsistently following isolation precautions E Presence of an invasive device, e.g., central venous catheter, endotracheal tube, urinary catheter Preferred response: E Rationale Invasive devices are often required to provide needed treatment to hospitalized patients, particularly when critically ill These devices can serve as entry points for infections which can result in the development of HAIs More than 90% of blood stream infections (BSIs) and hospital acquired pneumonias, and almost 80% of hospital acquired urinary tract infections (UTIs) occur in patients with invasive devices More than half of these infections are considered preventable Performing proper hand hygiene is an important factor in HAI prevention, including device-associated infections and infections that are transmitted between patients and care providers Isolation precautions and personal protective equipment (PPE) are additional key prevention practices in disease transmission between infected and noninfected patients, thus preventing the spread of transmissible HAIs Patients with weakened or immature immune systems are at increased risk of developing HAIs However, with adherence to isolation precautions, use of PPE, and proper hand hygiene, the risk of infection while in the intensive care unit (ICU) should be similar to other ICU patients Which of the following practices, as part of an evidence-based “bundle” approach, have been shown to reduce the incidence of surgical site infections? A Adhesive wound closure as opposed to sutures B Antibiotic-containing ointments applied to the incision C Razor to remove hair at the incision site D Timely administration of prophylactic antibiotics before and after surgery Preferred response: D Rationale Using a razor has actually been shown to increase the risk of infection, and the currently available evidence suggests that removing hair with clippers is better There is no evidence to support either the use of adhesive wound closures versus sutures or antibioticcontaining ointments at the incision site Conversely, there is consistent evidence to support strict adherence to administration of prophylactic antibiotics Which of the following components is not recommended as part of routine central line–associated bloodstream infection prevention bundles? A Daily chlorhexidine bathing treatment B Exchanging the central line every days C Maximal barrier precautions during insertion D Scrub the hub or access port with friction and an appropriate antiseptic prior to each access Preferred response: B e172 S E C T I O N XV Pediatric Critical Care: Board Review Questions Rationale Per the CDC’s Guidelines for the Prevention of Intravascular Catheter-Related Infections, the insertion of a central venous catheter (CVC) should be done using aseptic technique and maximal sterile barrier precautions, including use of a cap, mask, sterile gown, sterile gloves, and a sterile full body drape Given that contamination from skin flora, hubs, and access ports are significant contributors to CLABSIs, daily chlorhexidine bathing and antiseptic friction scrub prior to each access of the line are all standard elements of prevention bundles Routine replacement of properly functioning CVCs is not supported by evidence as an infection prevention strategy For critically ill children with indwelling bladder catheters, what is the most effective intervention to reduce the incidence of catheter-associated urinary tract infection? A Irrigate the catheter with antibiotics daily B Maintain a closed drainage system C Remove the catheter D Use antibiotic impregnated catheters Preferred response: C Rationale Avoiding unnecessary indwelling catheters and minimizing the duration of those placed is the most effective way to prevent CAUTI Each day a catheter is in, the risk for bacteruria is 3–7%, so removing as soon as possible will reduce the risk for infection Prevention bundles include maintaining a closed drainage system to reduce the risk of contamination Evidence does not support the use of antimicrobial-impregnated catheters or bladder irrigation as part of a routine CAUTI prevention strategy Chapter 110: Pediatric Sepsis Which ONE of the following cardiovascular agents is recommended as the first-line agent for a patient with septic shock whose clinical picture is consistent with “warm shock” (i.e., normal to high cardiac output with low systemic vascular resistance (SVR) and low blood pressure)? A Dobutamine B Dopamine C Milrinone D Norepinephrine Preferred response: D Rationale Purely by tradition, a commonly selected initial agent for vasoactive support is dopamine, which provides both inotropic support at lower doses (5–10 mg/kg/min) and increased vasomotor tone at higher doses (.10 mg/kg/min) Often it is necessary to escalate the dopamine dosage to high levels (up to 20 mg/kg/min), at which point additional agents should be strongly considered More recently, the use of dopamine as an initial agent has been de-emphasized in favor of norepinephrine and epinephrine A newer agent, angiotensin II, has also recently become available for adults with distributive septic shock that takes advantage of the endogenous renin-angiotensin-aldosterone system While early studies have shown efficacy in adults, pediatric trials are lacking, and thus use is limited only to salvage efforts at this time 2 Which ONE of the following class of receptors recognizes pathogen associated molecular patterns? A ICAM-1 B Interleukin C NF-kB D TNF receptor E Toll-like receptors Preferred response: E Rationale The fundamental role of the immune system is to detect, contain, and eradicate invading pathogens The first step in this process involves pathogen recognition, which is achieved by the activation of pattern recognition receptors (PRRs) on immune cells by pathogen associated molecular patterns (PAMPS) Examples of PAMPS include lipopolysaccharide from the cell wall of gramnegative bacteria; lipoteichoic acid from the cell wall of grampositive bacteria; mannans from the cell wall of yeast; double stranded RNA of viruses; and unmethylated, CpG-rich DNA unique to bacterial genomes The most well studied PRRs include the family of Toll-like receptors (TLRs), which can have relatively specific recognition of PAMPS For example, TLR-4 recognizes lipopolysaccharide, whereas TLR-2 recognizes lipoteichoic acid Other examples of PRRs or PRR components include CD-14, scavenger receptors, NOD receptors, pentraxins, and collectins Which one of the following forms of shock best describes the hemodynamic alterations seen in patients with septic shock? A Cardiogenic shock B Hypovolemic shock C Obstructive shock D Variable combinations of cardiogenic, hypovolemic, and distributive forms of shock Preferred response: D Rationale Shock states can be grouped into four broad categories: hypovolemic, cardiogenic, obstructive, and distributive shock Septic shock is unique because all four forms of shock may be involved simultaneously The patient may have hypovolemic shock resulting from capillary leak, increased insensible water losses, poor intake, or decreased effective blood volume secondary to venodilation and arterial dilation (i.e., increased vascular capacitance) Cardiogenic shock manifests as depressed myocardial contractility and low cardiac output secondary to myocardial-depressant effects of bacterial toxins and inflammatory cytokines Obstructive shock can result indirectly from diffuse microvascular thrombosis or directly from abdominal compartment syndrome Distributive shock can result directly from abnormally low systemic vascular resistance, leading to maldistribution of blood flow, or can result indirectly from the inability of tissues to adequately use oxygen at the mitochondrial level (i.e., cytopathic hypoxia) The degree to which an individual patient manifests these physiologic perturbations is highly variable In some cases, patients display increased cardiac output with diminished systemic vascular resistance The presenting symptoms in this type of patient are tachycardia, a hyperdynamic precordium, bounding pulses, and warm, flushed skin characteristic of the distributive mode of shock or the so-called warm shock state Despite this clinical appearance, the perfusion of major organs during warm shock may remain highly compromised secondary to maldistribution of blood flow Alternatively, a patient with depressed cardiac CHAPTER 136 Board Review Questions output and elevated systemic vascular resistance has cool, mottled skin with diminished pulses and poor capillary refill characteristic of the cold shock state Limited data and our collective anecdotal experience suggest this latter presentation, cold shock, is more common in younger children compared to teenagers and adults It has been suggested that patients who develop community-acquired septic shock more commonly present to the ICU with signs of cold shock, whereas patients who develop septic shock secondary to catheter-related infections more commonly present to the ICU with signs of warm shock It is important to recognize that a given patient may transition from one shock state to another, and recognition and reassessment of these classes of shock are absolutely central to the choice of cardiovascular medications Which of the following provides the best rationale for prescribing hydrocortisone in patients with septic shock? A As an antiinflammatory agent B As an immune modulating agent C To compensate for relative adrenal insufficiency D To improve cardiac output Preferred response: C Rationale Because immune/inflammatory dysregulation is a well-accepted pathophysiologic concept in septic shock, there has been a great deal of effort in developing treatment strategies directly targeted at immune/inflammatory modulation Steroids have long been proposed as a general antiinflammatory strategy In many clinical settings, patients with septic shock demonstrate worsening of their shock temporally associated with antibiotic administration It is thought this phenomenon results from a massive release of bacterial toxins after antibiotic-mediated bacterial killing and a subsequent inappropriately exuberant immune/inflammatory response However, the use of high-dose steroids to blunt this response is now universally accepted to be of no benefit and potentially harmful A more recent approach to using steroids in septic shock involves the concept of relative adrenal insufficiency and an association between relative adrenal insufficiency and catecholamine refractory shock A landmark study by Annane and colleagues demonstrated a substantial benefit in adults with septic shock having “relative adrenal insufficiency” (based on cortisol levels and ACTH stimulation testing) and treated with replacement hydrocortisone However, a subsequent trial did not demonstrate the efficacy of hydrocortisone replacement, thus leading to an ongoing, unresolved controversy in the field Further, Boonen and colleagues reported a reduction in cortisol metabolism related to suppressed expression and activity of cortisol-metabolizing enzymes during adult critical illness, thereby adding another confounding variable when considering administration of corticosteroids for septic shock Conflicting data and controversy also exist in the pediatric septic shock population, and existing data are currently limited to meta-analyses, observational studies, and practitioner anecdotes and experience A retrospective analysis of an existing transcriptomic database of pediatric septic shock demonstrated that the administration of corticosteroids in pediatric septic shock was associated with the repression of genes corresponding to adaptive immunity, raising questions about potential harm associated with corticosteroid administration during septic shock Jardine and colleagues examined genes involved in cortisol synthesis, metabolism, and activity in critically ill pediatric patients using the tag e173 single nucleotide polymorphism (SNP) methodology They identified an SNP in the MC2R gene (which codes for the ACTH receptor) and demonstrated that the AA genotype was associated with a low free cortisol response to critical illness One report described the development and validation of a real-time subclassification method for septic shock using previously identified gene expression-based subclasses, which corresponded to genes for adaptive immunity and glucocorticoid receptor signaling The study reported that allocation to the subclass with decreased expression of the glucocorticoid receptor signaling pathway genes was independently associated with increased mortality, and adjunctive corticosteroid administration to patients in that subclass was independently associated with almost four times the risk of mortality It is possible that patients with septic shock and high levels of illness severity stand to benefit the most from adjunctive corticosteroids Funk and colleagues stratified a large cohort of adults with septic shock into quartiles of illness severity using APACHE II scores Corticosteroid administration was associated with decreased mortality for patients in the highest quartile of illness severity In contrast, when a large cohort of children with septic shock was stratified for baseline mortality risk using stratification biomarkers, corticosteroids were not associated with decreased mortality for patients in the intermediate or high baseline mortality risk groups The role of hydrocortisone replacement in pediatric septic shock represents another major challenge in the field that must be directly addressed by a large, multicenter, randomized trial Current barriers to conducting this important trial include lack of equipoise in the pediatric critical care community, lack of consensus regarding the definition of relative adrenal insufficiency, and our inability to select which patients with septic shock are most likely to benefit from adjunctive corticosteroids Thus at present, treatment guidelines suggest that hydrocortisone replacement therapy be considered for patients who appear refractory to resuscitative measures, have a known history of adrenal insufficiency, have already received exogenous steroids, or have an abnormal ACTH stimulation test result Given the lack of objective evidence supporting the efficacy of adjunctive corticosteroids, and accumulating evidence suggesting harm, the otherwise strong recommendation for corticosteroids in the current pediatric guidelines should be revised accordingly Chapter 111: Multiple Organ Dysfunction Syndrome A patient has a new onset three-organ failure with a reduction in platelet count to less than 100,000/uL, an elevated LDH, and renal dysfunction According to these criteria, what multiple organ failure (MOF) phenotype does this patient have? A Immune paralysis/lymphoid depletion syndrome B Secondary hemochromatosis–associated hepatopancreatic MOF C Sequential MOF D Thrombocytopenia-associated MOF (TAMOF) Preferred response: D Rationale TAMOF represents a thrombotic microangiopathy syndrome (TMA) mediated by microvascular thrombosis that can range from fibrin-mediated disseminated intravascular coagulation e174 S E C T I O N XV Pediatric Critical Care: Board Review Questions (DIC) to vWF multimer mediated secondary TMA/thrombotic thrombocytopenic purpura These patients commonly have reduced ADAMTS 13 activity that can respond to intensive plasma exchange with resolution of organ dysfunction The MOF phenotypes are not mutually exclusive A patient with multiple organ failure (MOF) develops nosocomial infections with gram-negative bacteria and fungus and also has viral reactivation This patient most likely has which MOF phenotype? A Hyperleukocytosis-associated MOF B Immune paralysis/lymphoid depletion C Sequential MOF D Thrombocytopenia-associated MOF (TAMOF) Preferred response: B Rationale This patient most likely has immune paralysis This is a syndrome marked by a profound Th2 response Whole blood ex vivo TNFa production is markedly reduced (,200 pg/mL) for greater than days in these patients In the authors’ center, patients with three-organ failure and a TNF-a response ,160 pg/mL all developed secondary infection Immune paralysis can be caused when apoptotic lymphocytes are phagocytized by monocytes/macrophages These patients commonly have an absolute lymphocyte count ,1000/mL for greater than days At autopsy these patients have lymphoid depletion Immune paralysis can be reversed by holding immune suppressants Subcutaneous low-dose GMCSF can reverse immune paralysis and nosocomial infection risk in patients not receiving immune suppressants A patient is admitted to the ICU with acute respiratory distress syndrome (ARDS) and is mechanically ventilated Over time the child develops an increasing alanine aminotransferase (ALT) and now meets criteria for liver and renal dysfunction What multiple organ failure (MOF) phenotype does this patient most likely have? A Hyperleukocytosis associated MOF B Immune paralysis/lymphoid depletion C Sequential MOF D Thrombocytopenia-associated MOF (TAMOF) Preferred response: C Rationale This child has sequential MOF that is commonly associated with viral/lymphoproliferative disease High levels of sFasL can cause liver injury in this population In transplant patients Epstein-Barr virus (EBV) viral IL-10 DNA intercalates into B cells, causing proliferation Holding immune suppressants and subsequent treatment with B-cell monoclonal antibody rituximab is the preferred treatment In nontransplant patients with a family history of similar disease, Xlinked immune-proliferative disease or another form of primary hemophagocytic lymphohistiocytosis (HLH) is likely These patients have absent NK cell/CTL cell activity due to a variety of known defects in perforin signaling These children are unable to kill viruses or cancer cells They are also unable to induce activated immune cell death The treatment is chemotherapy to stop immune proliferation followed by bone marrow transplantation to restore NK/CTL cell function For children with rheumatologic disease with arthralgia, serositis, and skin rash, the process is mediated by reduced T-regulatory cell function leading to uncontrolled inflammation These patients respond to pulse steroids or anakinra 4 A patient has hepatobiliary dysfunction and disseminated intravascular coagulation with a ferritin level 500 pg/L What multiple organ failure (MOF) phenotype is this patient most likely to have? A Hyperleukocytosis-associated MOF B Immune paralysis/lymphoid depletion C Macrophage activation syndrome D Thrombocytopenia-associated MOF (TAMOF) Preferred response: C Rationale Macrophage activation syndrome is the common end pathway of uncontrolled inflammation Begin by eradicating the source (dead or alive) Concomitantly consider the use of methylprednisone, IVIG, plasma exchange, tocilizumab, or anakinra to quell inflammation until the infectious/necrotic source is removed, and host metabolism is restored Chapter 112: Bites and Stings Which of the following is most consistent with coral snake envenomation? A Acute renal failure B Descending paralysis C Painful swelling and erythema surrounding the bite site D Uncontrolled bleeding Preferred response: B Rationale Coral snake envenomation classically produces a neurotoxic syndrome that can lead to a descending paralysis and life-threatening respiratory failure Local tissue injury, renal failure, and hemorrhage are more typically associated with pit viper envenomation Which of the following is true regarding pit viper envenomation? A Antivenin should be reserved only for those with shock or life-threatening bleeding B Antivenin can be safely administered on an outpatient basis C Compartment syndrome is common due to the severe degree of swelling with local tissue injury D Recurrence of coagulopathy may occur even after treatment with antivenin, resulting in life-threatening hemorrhage Preferred response: D Rationale Recurrence may present as new progressive swelling or coagulopathy after initial improvement with antivenin Providers must counsel patients regarding the risk of recurrence and necessary follow up at discharge to prevent significant morbidity and mortality True compartment syndrome is rare after pit viper bites Antivenin should be considered in victims with progressive tissue injury, coagulopathy, or systemic signs and symptoms such as vital sign abnormalities or vomiting Due to the risk of anaphylaxis, patients should be monitored in the ICU during and after antivenin administration CHAPTER 136 Board Review Questions Which of the following is not typically seen following widow spider envenomation? A Facial muscle spasms, lacrimation, and periorbital edema B Hypertension C Local tissue swelling D Severe pain Preferred response: C Rationale Widow spider envenomation is characterized by neurotoxicity without significant local injury The bite site may have a “target” appearance Neurotoxins produce painful, repeated muscle contraction usually starting at the bite site and radiating proximally Autonomic disturbances such as hypertension, tachycardia, and diaphoresis may also occur “Lactrodectus facies” describes the pattern of facial muscle spasms, lacrimation, flushing, and eyelid edema that may be seen Chapter 113: Hyperthermic Injury A 14-year-old male suffered heat exhaustion on a hot summer day after several hours of football practice He initially felt faint, complained of severe thirst, headache, and transiently seeing spots, and then vomited twice Paramedics found him to be hyperthermic (41.5°C) He was transported with active cooling efforts from the local emergency department to your pediatric intensive care unit because of concern for his neurologic status On arrival, his vital signs included a temperature of 38.4°C, pulse of 130 beats/min, and a blood pressure of 95/50 mm Hg His temperature normalized overnight, but this morning, although alert and fully oriented, he continues to feel tired and complains of severe, diffuse pain in his arms and legs The strength in his legs appears diminished, and his thighs and calves are tender to palpation Of the following, the MOST accurate statement would be A He is at risk for cardiac dysrhythmias secondary to hyperkalemia B Hypocalcemia should be treated aggressively C Laboratory findings are likely to include severe hypophosphatemia D Myocardial creatine kinase is likely to be greater than four times normal E Renal injury will primarily involve pigment damage to the glomeruli Preferred response: A Rationale This patient is exhibiting signs of rhabdomyolysis as a consequence of exertion and heat exhaustion Severe electrolyte abnormalities may be present as a result of the disruption of the skeletal muscle cell membrane Severe hyperkalemia and hyperphosphatemia may be present, in addition to hypocalcemia Severe hyperkalemia may lead to a wide range of cardiac electrographic changes and dysrhythmias including ST segment and T wave changes, ventricular tachycardia, and ventricular fibrillation Treatment of hyperkalemia with insulin, glucose, and bicarbonate may be necessary Administration of calcium should be reserved for symptomatic patients or as therapy for hyperkalemia Excess calcium administration may lead to later development of hypercalcemia and e175 calcium deposition in skeletal muscle Myoglobin, generated from the breakdown of skeletal muscle, enters the renal tubules forming casts in the collecting ducts and distal tubules The breakdown of myoglobin causes oxidative damage to the renal parenchyma A 7-month-old infant is brought to the emergency room after her grandfather left her in a car and forgot to drop her off at day care Rectal temperature was 41.5°C, heart rate is 185 beats per minute, and blood pressure is 74/35 mm Hg She was unresponsive and was endotracheally intubated Laboratory evaluation demonstrates the following: Laboratory test Result Sodium 142 mEq/L (142 mmol/L) Potassium 3.2 mEq/L (3.2 mmol/L) BUN 34 mg/dL (12.1 mmol/L) Creatinine 2.1 mg/dL (185.7 µmol/L) AST 550 U/L ALT 479 U/L International normalized ratio 2.7 Of the following, the best initial management strategy should include A Immersion in ice water B Dantrolene C Dialysis D Fluid resuscitation E Acetaminophen Preferred response: D Rationale This patient has hyperthermia with laboratories demonstrating multiorgan dysfunction A therapeutic goal is the acute and rapid cooling of the core temperature to 39°C Ice-water immersion has been shown to be effective at rapidly cooling a patient with heat stroke However, in an intubated patient that requires ongoing resuscitation, ice-water immersion presents logistical challenges and is often impractical In addition, infants have a large surface area to weight ratio and are thus at risk for hypothermia with icewater immersion Dantrolene is effective treatment for malignant hyperthermia or neuroleptic malignant syndrome Dantrolene has not been shown to be therapeutic for nonexertional heat stroke The etiology of acute kidney injury is multifactorial in the setting of heat-related injury and includes direct thermal injury, rhabdomyolysis with myoglobinuria, hypoperfusion, release of vasoactive mediators, and DIC While dialysis may be required with severe kidney injury, in the acute setting, cooling the patient and maintaining an adequate circulating volume are essential Heat stroke can lead to hypotension and shock from splanchnic vasoconstriction and cutaneous vasodilation In addition, excess water loss and dehydration can lead to a reduction in cardiac preload Fluid resuscitation is essential to establish an adequate circulatory volume and organ perfusion Fluid resuscitation also increases heat dissipation and decreases core temperature by improving cutaneous blood flow Acetaminophen is not helpful in heat stroke and should be avoided due to the potential to potentiate liver injury ... Thrombocytopenia-associated MOF (TAMOF) Preferred response: B Rationale This patient most likely has immune paralysis This is a syndrome marked by a profound Th2 response Whole blood ex vivo... Preferred response: C Rationale This child has sequential MOF that is commonly associated with viral/lymphoproliferative disease High levels of sFasL can cause liver injury in this population In transplant... but this morning, although alert and fully oriented, he continues to feel tired and complains of severe, diffuse pain in his arms and legs The strength in his legs appears diminished, and his thighs