W j q ( к е н сй т1 * о ft e * * i 5 page

I-46. The answer is C. (Chap. 9) A primary goal of palliative care medicine is to control pain in patients who are terminally ill. Surveys have found that 36–90% of individuals with advanced cancer have substantial pain, and an individualized treatment plan is necessary for each patient. For individuals with continuous pain, opioid analgesics should be administered on a scheduled basis around the clock at an interval based on the half-life of the medication chosen. Extended-release preparations are frequently used because of their longer half-lives. However, it is inappropriate to start immediately with an extended-release preparation. In this scenario, the patient was treated with a continuous intravenous infusion via patient-controlled analgesia for 48 hours to determine her baseline opioid needs. The average daily dose of morphine required was 90 mg. This total dose should be administered in divided doses two or three times daily (either 45 mg twice daily or 30 mg three times daily). In addition, an immediate-release preparation should be available for administration for breakthrough pain. The recommended dose of the immediate-release preparation is 20% of the baseline dose. In this case, the dose would be 18 mg and could be given as either 15 or 20 mg four times daily as needed.

I-47. The answer is E. (Chap. 9) Withdrawal of care is a common occurrence in intensive care units. More than 90%of Americans die without performance of cardiopulmonary resuscitation. When a family decides to withdraw care, the treating care team of doctors, nurses, and respiratory therapists must work together to ensure that the dying process will be comfortable for both the patient and the family. Commonly, patients receive a combination of anxiolytics and opioid analgesics. These medications also provide relief of dyspnea in the dying patient. However, they have little effect on oropharyngeal secretions (option A). The accumulation of secretions in the oropharynx can produce agitation, labored breathing, and noisy breathing that has been labeled the “death rattle.” This can be quite distressing to the family. Treatments for excessive oropharyngeal secretions are primarily anticholinergic medications, including scopolamine delivered transdermally (option E) or intravenously, atropine, and glycopyrrolate. Although placement of a nasal trumpet or oral airway (option D) may allow better access for suctioning of secretions, these can be uncomfortable or even painful interventions that are typically discouraged in a palliative care situation. N-acetylcysteine (option B) can be used as a mucolytic agent to thin lower respiratory secretions. Pilocarpine (option C) is a cholinergic stimulant

and increases salivary production.

I-48. The answer is A. (Chap. 10) In recent years, there has been increasing focus on both the safety and quality of health care provided throughout the world. An Institute of Medicine report identified safety as an essential component of quality in health care. Improving safety and quality in health care relies on understanding the frequency and type of adverse events that occur in the health care system. An adverse event is defined as an injury caused by medical management rather than the underlying disease of the patient. One of the largest studies that has attempted to quantify adverse events in hospitalized patients was the Harvard Medical Practice Study. In this study, the most common adverse event was an adverse drug event, which occurred in 19% of hospitalizations. Other common adverse events included wound infections (14%), technical complications of a procedure (13%), diagnostic mishaps (15%), and falls (5%).

I-49. The answer is A. (Chap. e2) Since 1993, numerous population studies have shown that 30–40% of American adults seek and or use at least one complementary and alternative medicine (CAM) approach. The most prevalent are nonmineral nonvitamin dietary supplements, relaxation, medication, massage, and chiropractic care. Approximately 1% of Americans use acupuncture. The most common reasons are for back or musculoskeletal pain and control of symptoms not adequately addressed by conventional therapy. CAM expenses are estimated to be $34 billion per year, representing 1.5% of total health care expenditures and 11% of out-of-pocket expenses.

I-50. The answer is E. (Chap. e4) Minority patients have poorer health outcomes from many preventable and treatable conditions such as cardiovascular disease, asthma, diabetes, cancer, and others. The causes of these differences are multifactorial and include social determinants (education, socioeconomic status, environment) and access to care (which often leads to more serious illness before seeking care). However, there are also clearly described racial differences in quality of care when patients enter the health care system. These differences have been found in cardiovascular, oncologic, renal, diabetic, and palliative care. Eliminating these differences will require systematic changes in health system factors, provider-level factors, and patient-level factors.

I-51. The answer is A. (Chap. e6) Breast cancer in pregnant women is defined as cancer diagnosed during pregnancy or up to 1 year after delivery. Only about 5% of all breast cancers occur in women younger than 40 years of age, and of those, approximately 25% are pregnancy-associated cancer. Needle biopsy of breast masses in pregnant women is often nondiagnostic, and false-positive test results may occur. Breast cancers diagnosed during pregnancy have a worse outcome than other breast cancers. The cancers tend to be diagnosed at a later stage (often the signs are thought to be related to pregnancy) and tend to have a more aggressive behavior. Approximately 30% of breast cancers found in pregnancy are estrogen receptor positive in contrast to 60–70% being estrogen receptor positive overall. Larger tumor size, positive axillary nodes, Her-2 positivity, and higher stage are all more common in pregnant women.

I-52. The answer is C. (Chap. 34) Chronic cough is one of the most common causes of referral to pulmonary, allergy, and otolaryngology practices and is frequently encountered in primary care. A cough is classified as chronic when it persists for longer than 8 weeks and has a wide range of differential diagnoses, including cardiac, pulmonary, upper airway, and gastrointestinal diseases. The initial history and physical examination is important in providing clues to the potential etiology,

particularly in the setting of a normal chest radiograph and examination. The most common causes of chronic cough in an otherwise normal individual are cough-variant asthma, gastroesophageal reflux disease, postnasal drip, and medications. In this patient, there are clues that should lead one to suspect cough-variant asthma as a potential cause. Asthma can present only with cough. Although this presentation is more common in children, it can present this way in adults as well. This patient does have triggers that include cold air and exercise, both of which can lead to increased bronchoconstriction. In addition, the parasympathetic–sympathetic balance favors bronchoconstriction that is worse in the early morning hours with cough late at night. Although spirometry demonstrating reversible airflow obstruction is typically seen in asthma, asthma has significant clinical variability, and lung function varies over time. In this patient, the spirometry results are normal, and the bronchodilator response is insufficient to diagnose reversibility, which requires a response of at least 12% and an increase of at least 200 mL in either the forced expiratory volume in 1 second (FEV₁) or forced vital capacity (FVC). To establish the diagnosis more definitively, demonstration of a fall in FEV₁ of at least 20% during a bronchoprovocation test with methacholine would be sufficient in this

clinical scenario to diagnose asthma and would be safe to perform in this patient with normal pulmonary function at baseline. An alternative approach would be to treat empirically with low-dose inhaled corticosteroids given the clinical history.

In many cases, the cause of chronic cough is multifactorial. This patient has minor symptoms of allergic rhinitis, which may be a contributing factor. Nasal corticosteroids may also be required, but given the reported triggers, would not be sole treatment. The patient gives no history to suggest GERD, which may be clinically silent. If the cough failed to improve with treatment for asthma, antacid medications may be indicated. Finally, increasing numbers of adults are becoming infected with Bordetella pertussis because individual immunity wanes in adulthood, and more parents are electing to forego childhood immunizations. In this scenario, the patient typically gives a history of an upper respiratory infection with a strong cough at the onset of the illness. When the illness has progresses to the recovery phase, diagnosis is typically made by serology, and culture is not useful.

I-53. The answer is A. (Chap. 34) Hemoptysis is a relatively common symptom that causes a significant degree of distress in the patient. In most individuals, the hemoptysis is mild and self-limited despite the anxiety that it causes. Worldwide, tuberculosis remains the most common cause of hemoptysis. However, in the United States, the most common cause of hemoptysis is acute bronchitis of viral or bacterial etiology. Given the acute nature of the illness and mild degree of hemoptysis, this patient’s presentation would be most consistent with the diagnosis of acute bronchitis. Antiplatelet or anticoagulant agents may increase the risk of bleeding but are not sufficient in the absence of an underlying cause to initiate hemoptysis. Moreover, these agents are typically associated with underlying alveolar rather than airway damage. Most patients who experience hemoptysis fear lung cancer, which can present with acute hemoptysis, but this patient’s report of primarily blood-streaked sputum would make this less likely, especially in the face of a normal chest radiograph. Lung abscesses rarely present with hemoptysis, and the typical presentation is one of a prolonged illness.

I-54. The answer is E. (Chap. 34) Life-threatening hemoptysis is a medical emergency. Defining massive hemoptysis can be difficult but generally should be viewed as any amount of hemoptysis that can lead to airway obstruction because most patients who die of hemoptysis die from asphyxiation and airway obstruction. The immediate management of hemoptysis is to establish a patent airway and establish the site of bleeding. The initial step is to place the patient with the bleeding side in a

dependent position. In this patient with a known lesion of the right upper lobe, he should be placed with the right side (not left) in a dependent position. The patient should be intubated with the largest possible endotracheal tube to allow for adequate suctioning. When immediately available, placement of a dual-lumen endotracheal tube can allow selective ventilation of the nonbleeding lung while providing access to continue suctioning from the affected side. Certainly, correction of any underlying coagulopathy would be important in the management of this patient. If conservative measures fail to stop the bleeding, the first step is to attempt embolization of the bleeding artery, but in rare instances, urgent surgical intervention may be required.

I-55. The answer is D. (Chap. 221) Microbial agents have been used as bioweapons as far back as the sixth century BC when water supplies were poisoned with Claviceps purpurea by the Assyrians. In modern times, science that has been often sponsored by governmental agencies has lead to new ways to enhance and spread microbial bioweapons. Bioterrorism should be delineated from biowarfare. Although bioterrorism has the potential to lead to thousands of deaths if used in a large-scale manner, the primary impact is the fear and terror generated by the attack. However, biowarfare specifically targets mass casualties and seeks to weaken the enemy. The Working Group for Civilian Biodefense has outlined key features that characterize agents that are the most effective bioweapons. These 10 features are:

1. High morbidity and mortality rates

2. Potential for person-to-person spread

3. Low infective dose and highly infectious by the aerosol route

4. Lack of rapid diagnostic capability

5. Lack of a universally available effective vaccine

6. Potential to cause anxiety

7. Availability of pathogen and feasibility of production

8. Environmental stability

9. Database of prior research and development 10. Potential to be weaponized

A lack of effective and available treatment is not one of the characteristics of an effective bioweapon. Bacillus anthracis is the causative organism of anthrax, one of the most prototypical microbial bioweapons, but many antibiotics have efficacy against anthrax and can be lifesaving if initiated early.

I-56. The answer is B. (Chap. 221) Yersinia pestis is a gram-negative rod that causes the plague and has been one of the most widely used bioweapons over the centuries. Although Y. pestis lacks environmental stability, it is highly contagious and has a high mortality rate, making it an effective agent of bioterrorism. There are two major syndromes caused by Y. pestis that reflect the mode of infection. These patients presented with symptoms typical of bubonic plague, which still exists widely in nature. In the United States, the area with the greatest number of naturally occurring cases of bubonic plague is in the Southwest with transmission occurring via contact with infected animals or fleas. In this case, infected animals or fleas were present in the concentrated population of an immigrant camp that had poor sanitation. After an individual is bitten by an infected vector, the bacteria travel through the

lymphatics to regional lymph nodes, where they are phagocytized but not destroyed. The organisms can then multiply with the cells, leading to inflammation, painful and markedly enlarged lymph nodes, and fever. The affected lymph nodes can develop necrosis and are characteristically called buboes. Infection can progress to severe sepsis and death. The mortality rate for treated bubonic plague is 1– 15% and 40–60% in untreated cases. When Y. pestis is used as an agent of bioterrorism, it is aerosolized to a large area, and the affected cases present primarily with pneumonic plague. Pneumonic plague presents with fever, cough, hemoptysis, and gastrointestinal symptoms that occur 1–6 days after exposure. Without treatment, pneumonic plague has an 85% morality rate with death occurring rapidly within 2–6 days. The treatment for Y. pestis could include aminoglycosides or doxycycline.

I-57. The answer is D. (Chap. 221) In the event of a bioterrorism attack, botulinum toxin would be most likely delivered by either aerosol or contamination of the food supply. Contamination of the water supply is possible, but it is not an optimal route for bioterrorism. Botulinum toxin is inactivated by chlorine, which is used in many water supplies for purification. In addition, heating any food or water to greater than 85°C for longer than 5 minutes will inactivate the toxin. Finally, there is an environmental decay rate of 1% per minute. So the time interval between release and ingestion would need to be very short, which would be difficult with an entire city water supply.

I-58. The answer is B. (Chap. 221) Anthrax is caused by the gram-positive spore-forming rod Bacillus anthrax. Anthrax spores may be the prototypical disease of bioterrorism. Although not spread person to person, inhalational anthrax has a high mortality and a low infective dose (five spores) and may be spread widely with aerosols after bioengineering. It is well documented that anthrax spores were produced and stored as potential bio-weapons. In 2001, the United States was exposed to anthrax spores delivered as a powder in letters. Of 11 patients with inhalation anthrax, five died. All 11 patients with cutaneous anthrax survived. Because anthrax spores can remain dormant in the respiratory tract for 6 weeks, the incubation period can be quite long, and postexposure antibiotics are recommended for 60 days. Trials of a recombinant vaccine are underway.

I-59. The answer is D. (Chap. 221) The three major clinical forms of anthrax are gastrointestinal (GI), cutaneous, and inhalational. GI anthrax results from eating contaminated meat and is an unlikely bioweapon. Cutaneous anthrax results from contact with the spores and results in a black eschar lesion. Cutaneous anthrax had a 20% mortality before antibiotics became available. Inhalational anthrax typically presents with the most deadly form and is the most likely bioweapon. The spores are phagocytosed by alveolar macrophages and transported to the mediastinum. Subsequent germination, toxin elaboration, and hematogenous spread cause septic shock. A characteristic radiographic finding is mediastinal widening and pleural effusion. Prompt initiation of antibiotics is essential because the mortality rate is likely 100% without specific treatment. Inhalational anthrax is not known to be contagious. Provided that there is no concern for release of another highly infectious agent such as smallpox, only routine precautions are warranted.

I-60. The answer is C. (Chap. 221) Using the characteristics listed in the question, the Centers for Disease Control and Prevention developed classifications of biologic agents that are based on their potential to be used as bioweapons. Six types of agents have been designated as category A: Bacillus anthracis, botulinum toxin, Yersinia pestis, smallpox, tularemia, and the many viruses that cause viral hemorrhagic fever. Those viruses include Lassa virus, Rift Valley fever virus, Ebola virus, and yellow fever virus.

I-61. The answer is C. (Chap. 222) Chemical agents were first used in modern warfare during World Wa r I when 1.3 million died as a result of chemical agents. Since then, chemical agents have been used during warfare and bioterrorism, but most agents have a fairly low associated mortality rate. The chemical agents generally fall into one of five categories: nerve agents, asphyxiants, pulmonary damaging, vesicants, and behavior altering or incapacitating. Nerve agents include cyclohexyl sarin, sarin, soman, tabun, and VX and largely exert their effects through acetylcholinesterase inhibition. The most common asphyxiant is cyanide, which is liberated through cyanogen chloride or hydrogen cyanide. Chlorine gas, hydrogen chloride, nitrogen oxide, and phosgene are common agents that primarily cause pulmonary damage and adult respiratory distress syndrome. Vesicants include mustard gas and phosgene oxime, and agent 15/BZ is the primary chemical causing alterations in behavior or incapacitation.

I-62. The answer is D. (Chap. 222) Sulfur mustard was first used as a chemical warfare agent in World Wa r I. This agent is considered a vesicant and has a characteristic odor of burning garlic or horseradish. It is a threat to all exposed epithelial surfaces, and the most commonly affected organs are the eyes, skin, and airways. Large exposures can lead to bone marrow suppression. Erythema resembling a sunburn is one of the earliest manifestations of sulfur mustard exposure and begins within 2 hours to 2 days of exposure. The timing of exposure can be delayed as long as 2 days depending on the severity of exposure, ambient temperature, and humidity. The most sensitive body areas are warm, moist locations, including the axillae, perineum, external genitalia, neck, and antecubital fossae. Blistering of the skin is frequent and may be anything from small vesicles to large bullae. The bullae are dome shaped and flaccid. Filled with clear or straw-colored fluid, these bullae are not hazardous because the fluid does not contain any vesicant substances. The respiratory passages are also affected. With mild exposure, the only manifestation may be a complaint of irritation and congestion. Laryngospasm may occur. In severe cases, there is necrosis of the airways with pseudomembrane formation. The damage that occurs after sulfur mustard exposure is airway predominant, and alveolar damage is very rare. The eyes are particularly sensitive to sulfur mustard and have a shorter latency period than the skin injury. Almost all exposed individuals develop redness of the eyes. With higher exposure, there is a greater severity of conjunctivitis and corneal damage. The cause of death after mustard gas exposure is sepsis or respiratory failure, but the mortality rate is typically low. Even during World Wa r I, when antibiotics and endotracheal intubation were not available, the mortality rate was only 1.9%. There is no antidote to sulfur mustard. Complete decontamination in 2 minutes stops clinical injury, and decontamination within 5 minutes can decrease skin injury by half. Treatment is largely supportive.

I-63. The answer is A. (Chap. 222) Chlorine gas exposure primarily causes pulmonary damage and edema with respiratory distress syndrome. The initial decontamination of a victim exposed to chlorine gas should include removal of all clothing if no frostbite is present. The victim should gently wash the skin with soap and water with care to avoid aggressive bathing that may lead to serious abrasion of the skin. The eyes are flushed with water or normal saline. Supportive care should include forced rest, fresh air, and maintenance of a semiupright position. Oxygen is not required because the patient is not hypoxemic or in any respiratory distress. Delayed pulmonary edema can occur even if the patient is initially asymptomatic. Thus, observation for a period of time after exposure is required.

I-64 and I-65. The answers are D and D, respectively. (Chap. 222) This patient has symptoms of an acute cholinergic crisis as seen in cases of organophosphate poisoning. Organophosphates are the “classic” nerve agents, and several different compounds may act in this manner, including sarin, tabun, soman, and cyclosarin. Except for agent VX, all of the organophosphates are liquid at standard room temperature and pressure and are highly volatile, with the onset of symptoms occurring within minutes to hours after exposure. VX is an oily liquid with a low vapor pressure; therefore, it does not acutely cause symptoms. However, it is an environmental hazard because it can persist in the environment for a longer period. Organophosphates act by inhibiting tissue synaptic acetylcholinesterase. Symptoms differ between vapor exposure and liquid exposure because the organophosphate acts in the tissue upon contact. The first organ exposed with vapor exposure is the eyes, causing rapid and persistent pupillary constriction. After the sarin gas attacks in the Tokyo subway in 1994 and 1995, survivors frequently complained that their “world went black” as the first symptom of exposure. This is rapidly followed by rhinorrhea, excessive salivation, and lacrimation. In the airways, organophosphates cause bronchorrhea and bronchospasm. It is in the alveoli that organophosphates gain the greatest extent of entry into the blood. As organophosphates circulate, other symptoms appear, including nausea, vomiting, diarrhea, and muscle fasciculations. Death occurs with central nervous system penetration causing central apnea and status epilepticus. The effects on the heart rate and blood pressure are unpredictable. Treatment requires a multifocal approach. Initially, decontamination of clothing and wounds is important for both the patient and the caregiver. Clothing should be removed before contact with the health care provider. In Tokyo, 10% of emergency personnel developed miosis related to contact with patients’ clothing. Three classes of medication are important in treating organophosphate poisoning, anticholinergics, oximes, and anti-convulsant agents. Initially, atropine at doses of 2–6 mg should be given intravenously or intramuscularly to reverse the effects of organophosphates at muscarinic receptors; it has no effect on nicotinic receptors. Thus, atropine rapidly treats life-threatening respiratory depression but does not affect neuromuscular or sympathetic effects. This should be followed by the administration of an oxime, which is a nucleophile compound that reactivates the cholinesterase whose active site has been bound to a nerve agent. Depending on the nerve agent used, oxime may not be helpful because it is unable to bind to “aged” complexes that have undergone degradation of a side chain of the nerve agent, making it negatively charged. Soman undergoes aging within 2 minutes, thus rendering oxime therapy useless. The currently approved oxime in the United States is 2-pralidoxime. Finally, the only anticonvulsant class of drugs that is effective in seizures caused by organophosphate poisoning is the benzodiazepines. The dose required is frequently higher than that used for epileptic seizures, requiring the equivalent of 40 mg of diazepam given in frequent doses. All other classes of anticonvulsant medications, including phenytoin, barbiturates, carbamazepine, and valproic acid, will not improve seizures related to organophosphate poisoning.

I-66. The answer is D. (Chap. 223) Detonation of a nuclear device is the most likely scenario of radiation bioterror. The initial blast will cause acute mortality caused by the shock wave and thermal damage. Subsequent mortality would be caused by acute radiation exposure and fallout to more distant populations that largely depend on weather patterns. The initial detonation releases mostly highly damaging gamma particles and neutrons. Alpha and beta particles are not highly toxic in this situation. Alpha particles are large, have limiting penetrating power, and are stopped by cloth and human skin. Beta particles, although small, travel only a short distance (a few millimeters) in tissue and cause mostly burn-type injuries. Radioactive iodine is a beta particle emitter. Acute radiation syndrome causes death by hematopoietic bone marrow suppression and aplasia; gastrointestinal tract damage with

malabsorption and translocation of bacteria; and in severe cases, neurologic damage. Appropriate medical supportive therapy can reduce mortality and allow patient with more severe exposure to survive. Radiation causes dose-dependent bone marrow suppression that is irreversible at high doses. Bone marrow transplantation is controversial in cases of non-recovery of bone marrow. The acute exposure symptoms, predominantly thermal injury, respiratory distress, and GI symptoms, make resolve within days. However, subsequent bone marrow dysfunction typically develops within 2 weeks but may take as long as 6 weeks to manifest.

I-67. The answer is D. (Chap. 223) Much of the initial damage related to a “dirty” bomb is related to the power of the blast rather than the radiation. After a terrorist attack, it is important to identify all individuals who might have been exposed to radiation. The initial treatment of these individuals should be to stabilize and treat the most severely injured ones. Those with severe injuries should have contaminated clothing removed before transportation to the emergency department, but further care should not be withheld for additional decontamination because the risk of exposure to health care workers is low. Individuals with minor injuries who can be safely decontaminated without increasing the risk of medical complications should be transported to a centralized area for decontamination. A further consideration regarding treatment after radiation exposure is the total dose of radiation that an individual was exposed to. At a dose less than 2 Gy, there are usually no significant adverse outcomes, and no specific treatment is recommended unless symptoms develop. Many individuals will develop flulike symptoms. However, a complete blood count should be obtained every 6 hours for the first 24 hours because bone marrow suppression can develop with radiation exposure as low as 0.7 Gy. The earliest sign of this is a fall in the lymphocyte count of greater than 50%. Potential treatments of radiation exposure include use of colony-stimulating factors and supportive transfusions. Stem cell transfusion and bone marrow transplantation can be considered in the case of severe pancytopenia that does not recover. However, this is controversial, given the lack of experience with the procedure for this indication. After the Chernobyl nuclear reactor accident, none of the bone marrow transplants were successful.

I-68. The answer is B. (Chap. 16) The patient has a classic presentation of malignant hyper-thermia likely caused by succinylcholine or inhalational anesthetic administration as part of her anesthetic regimen. This syndrome occurs in individuals with inherited abnormality of skeletal muscle sarcoplasmic reticulum that causes a rise in intracellular calcium content after inhalational anesthetic or succinylcholine administration. The syndrome presents with hyperthermia, or an uncontrolled increase in body temperature that exceeds the ability of the body to lose heat; muscular rigidity; and acidosis, cardiovascular instability, and rhabdomyolysis. Because the temperature dysregulation is not attributable to alteration in hypothalamic set point, antipyretics such as acetaminophen, ibuprofen, and corticosteroids are ineffective at treating the condition. Haloperidol is associated with neuroleptic malignant syndrome and should not be used to treat this condition. Physical cooling in addition to dantrolene are the treatments of choice. Dantrolene disrupts excitation–contraction coupling in skeletal muscle, thereby diminishing thermogenesis. Dantrolene may also be used in neuroleptic malignant syndrome and occasionally the serotonin syndrome.

Date: 2016-04-22; view: 587