A 32-year-old woman with type 1 diabetes mellitus has had progressive renal failure over the past 2 years. She is not yet on dialysis. Examination shows no abnormalities. Her hemoglobin concentration is 9 g/dL, hematocrit is 28%, and mean corpuscular volume is 94 m³. A blood smear shows normochromic, normocytic cells. Which of the following is the most likely cause?

(A) Acute blood loss

(B) Chronic lymphocytic leukemia

(C) Erythrocyte enzyme deficiency

(D) Erythropoietin deficiency

(E) Immunohemolysis

(F) Microangiopathic hemolysis

(G) Polycythemia vera

(H) Sickle cell disease

(I) Sideroblastic anemia

(J) β-Thalassemia trait

(Answer: D)

Patient Information
Age: 18 years
Gender: F, self-identified
Ethnicity: unspecified
Site of Care: emergency department

History
Reason for Visit/Chief Concern: "My roommate took a lot of pills and said she wanted to die."

History of Present Illness:
•   patient brought by ambulance 2 hours after a suspected acetaminophen overdose
•   roommate had returned to their dorm and found the patient distraught; patient was holding an empty bottle of acetaminophen and said, "I just want to die."
•   roommate estimates patient consumed 20 to 30 tablets of 500-mg acetaminophen

Past Medical History:
•   generalized anxiety disorder
•   major depressive disorder

Medications:
•   citalopram

Allergies:
•   no known drug allergies

Family History:
•   noncontributory

Physical Examination

•   Appearance: awake and alert but distraught and fearful; patient says, "This was totally stupid."
•   Pulmonary: clear lung fields
•   Cardiac: regular rhythm; S₁ and S₂, with an early systolic murmur
•   Abdominal: soft and nontender; liver and spleen cannot be palpated
•   Neurologic: no abnormalities; fully oriented

Question: In addition to obtaining serum acetaminophen concentration, which of the following is the most appropriate next step in management?

(A) Administer N-acetylcysteine

(B) Arrange hemodialysis

(C) Gastric lavage

(D) Initiate sodium bicarbonate infusion

(Answer: A)

A 35-year-old woman is brought to the emergency department because of worsening pain and swelling of her right knee for the past 2 days. She has been taking acetaminophen for the knee pain during the past 2 days, but the pain is worse today. She has not had any trauma to the knee or any previous problems with her joints. She is otherwise healthy and she currently takes an oral contraceptive. She is sexually active and has a 10-year-old son who lives with her. She is a receptionist at a local hotel and she tells you she must stand often while working. She is 160 cm (5 ft 3 in) tall and weighs 52 kg (115 lb); BMI is 20 kg/m². Temperature is 37.9°C (98.9°F). The right knee is erythematous, swollen, and tender; there is pain on movement. No other joints are affected. X-ray of the knee shows an effusion but no structural abnormalities of the joint.

Which of the following is the most appropriate next step in diagnosis?

(A) Arthrocentesis of the knee

(B) Blood cultures

(C) MRI of the knee

(D) Urine cultures

(Answer: A)

Arthrocentesis is done. The synovial fluid is cloudy. Gram stain is negative. Analysis of the synovial fluid shows a leukocyte count of 120,000/mm³ and 90% neutrophils. Which of the following is the most appropriate additional test on the synovial fluid?

(A) Culture for bacteria

(B) Glucose measurement

(C) Polarized light microscopy

(D) Protein level

(Answer: A)

A 17-year-old girl comes to the office for an examination prior to entering college. She reports that she feels well but is nervous about leaving home for the first time. She states that she has tried to diet to improve her appearance but that food restriction often "backfires" because she becomes hungry and then engages in episodes of binge eating. She reports a loss of control during these episodes, saying, "It's like I stop thinking at all and before I know it, I have eaten two pizzas." She induces vomiting several times during each binge and has developed a pattern of binging and purging every evening. She has no history of serious illness and takes no medications. She is 165 cm (5 ft 5 in) tall and weighs 57 kg (125 lb); BMI is 21 kg/m2. Vital signs are within normal limits. Physical examination shows dry mucous membranes, erosion of enamel on the lingual surface of the front teeth, and hypertrophy of the parotid gland. Serum studies are most likely to show which of the following sets of findings in this patient?

             Potassium           Bicarbonate

(A)        Decreased            decreased

(B)        Decreased            increased

(C)        Increased             decreased

(D)        Increased             increased

(E)        Normal                 decreased

(F)        Normal                 increased

(Answer: B)

A hospitalized 57-year-old man has had severe progressive pain in his left knee since awakening 2 hours ago. He was admitted to the hospital 2 days ago for an acute myocardial infarction. Cardiac catheterization showed occlusion of the left anterior descending artery, and he underwent placement of a stent. Current medications include aspirin, metoprolol, lisinopril, simvastatin, clopidogrel, and heparin. Vital signs are within normal limits. Examination of the knee shows a large effusion. The knee is hot to touch and erythematous. He holds the knee in 30 degrees of flexion; the pain is exacerbated with further flexion or extension. Laboratory studies show:

Hematocrit                 40%

Leukocyte count        13,000/mm3

Serum

      Ca2+                     9.2 mg/dL(D)

      Urea nitrogen       15 mg/dL

      Creatinine             1.0 mg/dL

      Albumin                3.6 mg/dL

An x-ray of the left knee shows calcification of the synovium. Which of the following is the most likely diagnosis?

(A) Deep venous thrombosis

(B) Gonorrhea

(C) Gout

(D) Hemarthrosis

(E) Pseudogout

(F) Septic arthritis

(Answer: E)

A 21-year-old woman comes to the office for counseling prior to conception. She is recently married and would like to conceive within the next year. She does not eat meat, fish, or dairy products and wishes to decrease the risks of her diet on her baby. Menses occur at regular 28-day intervals and last 5 days. She does not smoke or drink alcohol. She takes no medications. She is 157 cm (5 ft 2 in) tall and weighs 50 kg (110 lb); BMI is 20 kg/m2. Physical examination shows no abnormalities. Pelvic examination shows a normal appearing vagina, cervix, uterus, and adnexa. Which of the following is most likely to decrease the risk of fetal anomalies in this patient?

(A) Adjusting diet to include more sources of protein during the first trimester

(B) Beginning folic acid supplementation prior to conception

(C) Calcium supplementation during the first trimester

(D) Iron supplementation during the first trimester

(E) Soy protein shakes throughout pregnancy and lactation

(F) Randomized clinical trial

(Answer: B)

A 10-year-old boy is brought for a follow-up examination 2 days after he was seen in the emergency department because of hives, hoarseness, and light-headedness. His symptoms began 15 minutes after he was stung by a bee and lasted approximately 60 minutes; they resolved before he was treated. He has been stung by bees three times over the past year, and each reaction has been more severe. Examination shows no abnormalities. Which of the following is the most appropriate recommendation to prevent future morbidity and mortality from this condition?

(A) Avoid areas known to have bees

(B) Avoid wearing colorful clothing outside

(C) Carrying diphenhydramine tablets

(D) Carrying self-injectable epinephrine

(E) Seek immediate medical attention following any future sting

(Answer: D)

A cohort study is conducted to compare the incidence of adverse effects of a recently approved antihypertensive pharmacotherapy with that of conventional therapy. A total of 20,000 patients are enrolled. Twelve thousand are prescribed the recently approved therapy, and 8,000 are prescribed conventional therapy. Patients in the study and control groups are matched for baseline blood pressure, age, and gender. Data are collected from the records of the patients' ongoing clinical care. Results show that those receiving the newly approved treatment have twice the incidence of fatigue compared with those receiving the conventional treatment. The results are statistically significant (P=0.01). Which of the following potential flaws is most likely to invalidate this study?

(A) Publication bias

(B) Selection bias

(C) Type I error

(D) Type II error

(Answer: B)

Three days after hospitalization for diabetic ketoacidosis, an 87-year-old woman refuses insulin injections. She says that her medical condition has declined so much that she no longer wishes to go on living; she is nearly blind and will likely require bilateral leg amputations. She reports that she has always been an active person and does not see how her life will be of value anymore. She has no family and most of her friends are sick or deceased. On mental status examination, she is alert and cooperative. She accurately describes her medical history and understands the consequences of refusing insulin. There is no evidence of depression. She dismisses any attempts by the physician to change her mind, saying that the physician is too young to understand her situation. She says, "I know I will die, and this is what I want." Which of the following is the most appropriate next step in management?

(A) Discharge the patient after she has signed an "against medical advice" form

(B) Seek a court order to appoint a legal guardian

(C) Offer insulin but allow the patient to refuse it

(D) Admit to the psychiatric unit

(E) Administer insulin against the patient's wishes

(Answer: C)

A 45-year-old woman is hospitalized for management of Staphylococcus aureus endocarditis with persistent bacteremia. The patient is discussed during interdisciplinary rounds, which includes physicians, nurses, pharmacists, and social workers. During rounds, a pharmacy student notices that the patient missed two doses of her scheduled antibiotic last week but is unsure why. The physician and nurse are unaware of these missed doses, and the student does not mention her observation. Which of the following measures is most likely to improve communication within this interdisciplinary health care team?

(A) Conduct interdisciplinary rounds in a quieter location

(B) Encourage questions from all team members

(C) Implement a checklist for standardizing patient rounds

(D) Use computers during rounds to review medications

(Answer: B)