The following cases and commentary, which focus on high-value, cost-conscious care, are excerpted from ACP's Medical Knowledge Self-Assessment Program (MKSAP 15).
Case 1: Suspected deep vein thrombosis
A 50-year-old woman is evaluated in the emergency department for a 4-day history of pain, swelling, and erythema of the left leg. There is no history of recent immobilization, cancer, surgery, or deep venous thrombosis.
On physical examination, temperature is 37.7°C (100.0°F), blood pressure is 132/82 mm Hg, pulse rate is 65/min, and respiration rate is 16/min. Examination of the left leg discloses warmth and circumscribed erythema and tenderness limited to the posterior tibial portion of the leg. The circumference of the left leg is 1 cm greater than the right when measured 10 cm below the tibial tuberosity. Localized tenderness along the distribution of the deep venous system and pitting edema are absent as are venous varicosities.
Which of the following is the most appropriate next step in diagnosis?
A. CT of the leg
B. D-dimer assay
C. Duplex ultrasonography
D. MRI of the leg
Case 2: Pain and acute pancreatitis
A 34-year-old woman is evaluated for continued severe mid-epigastric pain that radiates to the back, nausea, and vomiting 5 days after being hospitalized for acute alcohol-related pancreatitis. She has not been able eat or drink and has not had a bowel movement since being admitted.
On physical examination, the temperature is 38.2°C (100.8°F), the blood pressure is 132/84 mm Hg, the pulse rate is 101/min, and the respiration rate is 20/min. There is no scleral icterus or jaundice. The abdomen is distended and diffusely tender with hypoactive bowel sounds.
Laboratory studies show leukocyte count 15,400/µL (15.4 × 109/L), aspartate aminotransferase 189 U/L, alanine aminotransferase 151 U/L, bilirubin (total) 1.1 mg/dL (18.8 µmol/L), amylase 388 U/L, and lipase 924 U/L.
CT scan of the abdomen shows a diffusely edematous pancreas with multiple peripancreatic fluid collections, and no evidence of pancreatic necrosis.
Which of the following is the most appropriate next step in the management of this patient?
A. Enteral nutrition by nasojejunal feeding tube
B. Intravenous imipenem
C. Pancreatic débridement
D. Parenteral nutrition
Case 3: Perioperative evaluation
An 82-year-old woman is evaluated at the hospital after tripping and falling. She has sustained a right hip fracture and needs urgent hip replacement. She reports no angina, chest discomfort, syncope, or presyncope. She has had no signs or symptoms of heart failure. Prior to her fall, she was active and walked daily.
On physical examination, temperature is normal, blood pressure is 164/82 mm Hg, and pulse is 96/min. BMI is 26. Point of maximal impulse is undisplaced. There is a normal S1 and a single S2. There is a grade 3/6 systolic ejection murmur on examination heard at the right upper sternal border that radiates to the left carotid artery. Carotid pulses are delayed.
Transthoracic echocardiogram demonstrates severe aortic stenosis and normal left ventricular size and function. Pulmonary pressures are normal.
Which of the following is the best perioperative management option?
A. Aortic balloon valvuloplasty
B. Aortic valve replacement
C. Intra-aortic balloon placement
D. Intravenous afterload reduction (nitroprusside)
E. Proceed directly to hip replacement
Case 4: Managing diverticular bleed
A 76-year-old man is evaluated in the emergency department after having passed a large amount of red and maroon blood per rectum. After this episode, the patient felt dizzy and stumbled but did not lose consciousness or injure himself. In the ambulance on the way to the emergency department, he passed more blood, and the blood pressure was 100/60 mm Hg and the pulse rate was 110/min. He has not had abdominal pain, nausea, vomiting, fever, or weight loss. He had a colonoscopy 1 year ago that showed a benign polyp and diverticulosis. His medical history includes hypertension and hypercholesterolemia, and his medications are hydrochlorothiazide, lisinopril, simvastatin, and aspirin.
On physical examination, the patient is pale; the blood pressure is 105/65 mm Hg and the pulse rate is 100/min. Abdominal examination is normal; there is dried blood in the perianal area, and rectal examination reveals normal tone but fresh blood on the examination glove. Laboratory studies reveal hemoglobin 10.1 g/dL (101 g/L) and normal biochemical studies, including blood urea nitrogen. Leukocyte count is 5600/µL (5.6 × 109/L) and platelet count is 348,000/µL (348 × 109/L); prothrombin time and activated partial thromboplastin time are normal.
Which of the following is the most appropriate next step in the management of this patient?
C. Intravenous access
D. Placement of a nasogastric tube with lavage
E. Technetium-labeled red blood cell scan
Case 5: Syncope evaluation
A 36-year-old woman is evaluated in the emergency department after collapsing suddenly while waiting in line at a county fair on a hot summer day. The patient states she felt nauseated and became diaphoretic and lightheaded. She sat on the ground and then lost consciousness. According to her son, she was unconscious for less than a minute, exhibited some twitching movements when she first lost consciousness, but had no incontinence or symptoms of confusion upon awakening. She had no further symptoms upon regaining consciousness. She has a history of hypertension and hyperlipidemia. Current medications are lisinopril and lovastatin.
On physical examination, temperature is normal, blood pressure is 142/80 mm Hg (supine) and 138/78 mm Hg (standing), pulse rate is 84/min (supine) and 92/min (standing), and respiration rate is 14/min. BMI is 35. Cardiac and neurologic examinations are normal. An electrocardiogram is normal.
Which of the following is the most appropriate management option for this patient?
C. Exercise stress test
D. Tilt-table testing
E. No further testing
Answers and commentary
Correct answer: B. D-dimer assay.
A patient in whom deep venous thrombosis (DVT) is suspected must undergo objective testing to exclude the diagnosis. Several imaging procedures can exclude DVT, but the diagnostic goal is to use the most efficient, least-invasive, and least-expensive method with the fewest side effects. A D-dimer assay is a simple, relatively noninvasive test that has been shown to have a high negative predictive value, especially if the suspicion for DVT is low. The Wells criteria have been established to help the clinician assess the likelihood of DVT, and studies have shown that with a low clinical suspicion (as in this patient) and a negative D-dimer assay, the presence of DVT can be reliably excluded without the need for more invasive or complex imaging.
In the Wells criteria, the following clinical variables each earn 1 point: active cancer; paralysis or recent plaster cast; recent immobilization or major surgery; tenderness along the deep veins; swelling of the entire leg; greater than a 3-cm difference in calf circumference compared with the other leg; pitting edema; and collateral superficial veins. The clinical suspicion that an alternative diagnosis is likely earns -2 points. Based on this system, the pretest probability of DVT is considered high in patients with scores of greater than or equal to 3, moderate in patients with scores of 1 to 2, and low in patients with scores less than or equal to 0. This patient's Wells score is -2, and the likelihood for DVT is therefore low. This patient's fever, circumscribed area of warmth, and tenderness localized to the posterior calf could represent cellulitis, a reasonable alternative to the diagnosis of venous thrombosis.
If the D-dimer assay is positive or the clinical suspicion is moderate to high for the presence of a DVT, an objective imaging study, such as ultrasonography, must be performed. Ultrasonography is highly sensitive and specific for detection of proximal (popliteal or above) DVT. However, ultrasonography has low sensitivity for identifying thrombi limited to the calf veins. About 1% to 2% of patients with a normal initial ultrasound have calf vein thrombosis that is destined to extend into the proximal veins, generally within 5 to 8 days.
Venography, the traditional gold standard for diagnosis of DVT, is rarely performed today because of its invasiveness, discomfort, costs, and complexity.
Neither an MRI nor CT of the leg has been substantially validated as a reliable diagnostic test for DVT.
- Negative D-dimer assay results and a low Wells criteria score reliably exclude a diagnosis of deep venous thrombosis and preclude the need for more invasive testing or complex imaging.
Correct answer: A. Enteral nutrition by nasojejunal feeding tube.
This patient has moderate to severe acute pancreatitis and after 5 days remains febrile, continues to be in pain, and cannot take in any oral nutrition. The patient will likely have an extended period before being able to take in oral nutrition. Two routes are available for providing nutrition in patients with severe acute pancreatitis: enteral nutrition and parenteral nutrition. Enteral nutrition is provided through a feeding tube ideally placed past the ligament of Treitz so as not to stimulate the pancreas. Parenteral nutrition is provided through a large peripheral or central intravenous line. Enteral nutrition is preferred over parenteral nutrition because of its lower complication rate, especially a lower infection rate. A meta-analysis of six studies with 263 participants compared enteral nutrition with total parenteral nutrition. Enteral nutrition was associated with a significantly lower incidence of infections, reduced surgical interventions to control complications of pancreatitis, and a reduced length of hospital stay. In another randomized, controlled trial, enteral nutrition showed a trend towards faster attenuation of inflammation, with fewer septic complications, and also was a dominant therapy in terms of cost-effectiveness.
Imipenem therapy is only helpful in acute pancreatitis when there is evidence of pancreatic necrosis. Pancreatic necrosis is diagnosed by a contrast-enhanced CT scan that shows nonenhancing pancreatic tissue. In patients with noninfected pancreatic necrosis, antibiotics may decrease the incidence of sepsis, systemic complications (for example, respiratory failure), and local complications (for example, infected pancreatic necrosis or pancreatic abscess). Randomized, prospective trials have shown no benefit from antibiotic use in acute pancreatitis of mild to moderate severity but may lead to development of nosocomial infections with resistant pathogens. Similarly pancreatic débridement is recommended only in patients with pancreatitis and infected pancreatic necrosis.
- Enteral feeding is the preferred route of providing nutrition in patients with severe acute pancreatitis.
Correct answer: E. Proceed directly to hip replacement.
The best perioperative management option for this patient is to proceed directly to hip replacement. Preoperative assessment of cardiovascular risk includes a careful physical examination, a thorough assessment for cardiopulmonary symptoms and exercise tolerance, as well as an evaluation of the type of surgery contemplated and indication (high versus low risk, elective versus nonelective). In the evaluation of patients prior to noncardiac surgery, cardiac murmurs are commonly encountered. This patient has clinical and echocardiographic findings consistent with aortic stenosis (delayed distal pulses, a radiating systolic murmur, and a single S2 due to delayed closure of the calcified aortic valve). Aortic stenosis is a slowly progressive disease process, and asymptomatic patients can remain event-free for prolonged time periods. As a consequence, prophylactic valve replacement is not performed in asymptomatic patients. In patients with significant aortic stenosis but with good preoperative exercise tolerance, surgical procedures are generally well tolerated. The patient in this question was asymptomatic and active prior to her fall. Most asymptomatic aortic stenosis patients who need noncardiac surgery can be managed conservatively with careful intraoperative attention to fluid balance. For patients with advanced cardiac disease, an anesthesiologist with additional cardiovascular training (cardiac anesthesiologist) may be preferred.
Percutaneous aortic balloon valvuloplasty is generally not performed for calcific aortic stenosis because serious complications, including aortic regurgitation and embolic stroke, occur in more than 10% of procedures, and restenosis occurs within a year in most patients. Rarely, valvuloplasty is considered in patients with severe, symptomatic aortic stenosis who require emergent noncardiac surgery and are not candidates for valve replacement. This is not an appropriate course of action in this patient.
In symptomatic patients, postponement of noncardiac surgery until after valve replacement should be considered, particularly if surgery is elective. This patient is asymptomatic and valve replacement is not indicated, and it would be unwise to postpone this patient's hip replacement surgery.
This patient is hemodynamically stable, and neither an intra-aortic balloon pump nor intravenous nitroprusside is indicated.
- Prophylactic aortic valve replacement is not performed in asymptomatic patients with aortic stenosis.
Correct answer: C. Intravenous access.
The likely source of gastrointestinal bleeding in this patient is lower, with diverticulosis and vascular ectasia being most likely. Although a brisk upper gastrointestinal bleeding source is possible, generally an elevated blood urea nitrogen level and symptoms referable to the upper gastrointestinal tract would be seen. The patient's recent colonoscopy and lack of other symptoms and large-volume bleeding make a neoplasm unlikely. Colonic ischemia generally presents with abdominal pain and only a small amount of bleeding. Regardless of the source of bleeding at this point in the emergency department, however, the first rule of management is to achieve hemodynamic stability. This patient is volume-depleted and not hemodynamically stable. Therefore, the most appropriate next step is to ensure proper intravenous access, generally via two large-bore peripheral catheters or a central line for volume repletion with crystalloid fluids and blood products as necessary.
A nasogastric tube may be considered after volume resuscitation if an upper gastrointestinal bleeding source were suspected, but given his lack of upper gastrointestinal symptoms and normal blood urea nitrogen concentration, this is unlikely. Further, if an upper gastrointestinal source were highly suspected, an esophagogastroduodenoscopy should be performed regardless of the lavage results, which have a high false-negative rate. Although a colonoscopy is the diagnostic test of choice to evaluate for diverticular bleeding, vascular ectasias, neoplasms, internal hemorrhoids, and other possible sources of lower gastrointestinal bleeding, again this should not occur before volume resuscitation. A bleeding scan would be indicated only if endoscopic evaluation is not revealing and the patient continues to bleed. Up to 90% of diverticular bleeding resolves spontaneously. If a bleeding diverticulum is detected on colonoscopy, it can be treated with epinephrine injection and/or thermal coagulation.
- Diverticular bleeding is one of the most common sources of lower gastrointestinal bleeding, but diagnosis and therapy via colonoscopy are secondary to volume resuscitation and achieving hemodynamic stability.
Correct answer: E. No further testing.
The patient's history is consistent with vasovagal (neurocardiogenic) syncope based on the history of prolonged standing and prodromal symptoms of nausea, lightheadedness, and diaphoresis. These presyncopal warning symptoms are highly sensitive for the diagnosis of vasovagal syncope if lasting for more than 10 seconds. Brief myoclonic jerking after losing consciousness is not unusual with syncope, especially vasovagal syncope. In addition, the normal physical examination, electrocardiogram, and lack of orthostasis on vital sign assessment all point toward vasovagal syncope.
Advanced cardiovascular diagnostic testing, such as an echocardiogram or exercise stress test, is not needed after a first episode of syncope when symptoms are characteristic for vasovagal syncope.
In suspected vasovagal syncope, a tilt-table test can be useful, providing a diagnosis in up to 60% of patients when done with pharmacologic stimulation. This test is indicated in patients with recurrent syncope as well as those with one episode who are at high risk based upon their occupation. However, this test has poor sensitivity, specificity, and reproducibility, and it is not indicated in most patients with suspected vasovagal syncope.
An electroencephalogram might be indicated to evaluate a first, unprovoked seizure, but despite this patient's few myoclonic jerks, there is no evidence of seizure activity, such as tongue biting, incontinence, or postictal confusion.
- Vasovagal syncope is typically associated with a prodrome of nausea, lightheadedness, and diaphoresis.