Amboss Flashcards
An 80-year-old woman is brought to the emergency department for left hip pain 30 minutes after she fell while walking around in her room. Examination shows left groin tenderness. The range of motion of the left hip is limited because of pain. An x-ray of the hip shows a linear fracture of the left femoral neck with slight posterior displacement of the femur. Which of the following arteries was most likely damaged in the patient’s fall?
A
Lateral femoral circumflex
B
Deep femoral artery
C
Medial circumflex femoral
D
Deep circumflex iliac
E
Obturator
F
Superior gluteal artery
C
Medial circumflex femoral
The medial circumflex femoral artery is a major branch of the profunda femoris. It courses medioposteriorly to the neck of the femur, where it supplies blood to the head and neck of the femur. A minority of femoral neck fractures will go on to develop osteonecrosis of the femoral head stemming from injuries to this artery and its small branches to the bone.
A 56-year-old man comes to the emergency department because of pain and swelling in his left leg. He has a history of pancreatic cancer and is currently receiving chemotherapy. Three weeks ago, he had a similar episode in his right arm that resolved without treatment. His temperature is 38.2°C (100.8°F). Palpation of the left leg shows a tender, cord-shaped structure medial to the medial condyle of the femur. The overlying skin is erythematous. Which of the following vessels is most likely affected?
A
Posterior tibial artery
B
Posterior tibial vein
C
Popliteal artery
D
Anterior tibial artery
E
Popliteal vein
F
Superficial femoral artery
G
External iliac artery
H
Great saphenous vein
I
External iliac vein
J
Deep femoral vein
K
Anterior tibial vein
Recurrent episodes of pain, swelling, and erythema in various locations in a patient with a history of pancreatic cancer are suggestive of malignant migratory thrombophlebitis (Trousseau syndrome).
H
Great saphenous vein
The great saphenous vein (GSV) originates at the base of the hallux, continues proximally by passing anterior to the medial malleolus, and then courses along the posterior aspect of the medial femoral condyle before running deep into the thigh to join the femoral vein. The GSV and the small saphenous vein make up the main veins of superficial venous system of the leg, which is commonly involved in cases of malignant migratory thrombophlebitis. Migratory thrombophlebitis in pancreatic cancer is believed to be a direct result of procoagulants by the tumor itself. This patient will require acute treatment with intravenous heparin followed by outpatient anticoagulation.
A 2050-g (4.5-lb) female newborn and a 2850-g (6.3-lb) female newborn are delivered at 37 weeks’ gestation to a 23-year-old, gravida 2, para 1 woman. The mother had no prenatal care. Examination of the smaller newborn shows a flattened nose and left-sided clubfoot. The hematocrit is 42% for the smaller newborn and 71% for the larger newborn. This pregnancy was most likely which of the following?
A
Monochorionic-diamniotic monozygotic
B
Dichorionic-diamniotic dizygotic
C
Dichorionic-diamniotic monozygotic
D
Dichorionic-monoamniotic monozygotic
E
Conjoined twins
Delivery of twins with a significant disparity in birth weight and hematocrit, along with evidence of oligohydramnios (e.g., clubfoot, flattened nose) in the smaller newborn, should raise concern for twin-to-twin transfusion syndrome.
A
Monochorionic-diamniotic monozygotic
Approximately 70% of monozygotic twin pregnancies are monochorionic-diamniotic. Sharing a common placenta can lead to twin-to-twin transfusion syndrome, a complication caused by unbalanced vascular anastomoses in which blood flows in a fixed direction from one twin to the other. Since the fetuses have separate amniotic sacs, this causes oligohydramnios (in the donor twin’s amniotic sac) and polyhydramnios (in the recipient twin’s amniotic sac). The donor twin develops anemia, oliguria, and complications of oligohydramnios (e.g., craniofacial abnormalities and clubfoot due to intrauterine growth restriction). The recipient twin develops polycythemia.
In monozygotic twinning events, chorionicity and amnionicity depend on the timing of cleavage. The pregnancy will be dichorionic-diamniotic if cleavage occurs 0–4 days after fertilization, monochorionic-diamniotic if cleavage occurs 4–8 days after fertilization, and monochorionic-monoamniotic if cleavage occurs 8–12 days after fertilization.
A 3-year-old girl is brought to the cardiologist because of sweating and respiratory distress while eating. She is at the 30th percentile for height and 15th percentile for weight. Echocardiography shows a defect in the membranous portion of the interventricular septum and a moderately decreased left ventricular ejection fraction. Physical examination is most likely to show which of the following findings?
A
Systolic murmur that increases with hand clenching
B
Wide, fixed splitting of the second heart sound
C
Systolic murmur that increases with forced exhalation against a closed glottis
D
Diastolic murmur preceded by opening snap
E
Continuous murmur that is loudest at the second heart sound
A
Systolic murmur that increases with hand clenching
50%
Hand clenching increases systemic vascular resistance and afterload, which causes left-to-right shunting of blood and makes the systolic murmur in VSD more audible. Small VSDs may cause a loud systolic murmur with palpable thrill due to the large pressure differential between the left and right ventricles, while large VSDs are typically less obvious on auscultation. If left untreated, VSDs can lead to pulmonary hypertension and heart failure.
A systolic murmur that increases with forced exhalation against a closed glottis (Valsalva maneuver) is characteristic of hypertrophic obstructive cardiomyopathy (HOCM). The Valsalva maneuver reduces both preload and left ventricular afterload, which would exacerbate the subaortic stenosis in HOCM but reduce the left-to-right shunt of blood in VSD. The Valsalva maneuver would therefore decrease this patient’s murmur intensity.
A 40-year-old woman is brought to the emergency department after falling down the stairs in her house. She began taking levofloxacin 4 days ago for community-acquired pneumonia and takes no other medications. Physical examination shows severe tenderness, swelling, erythema, and decreased range of motion of her left ankle joint. An MRI of her left ankle shows a partial tear in the anterior talofibular ligament and a complete tear in the tendon of the muscle that originates from the lower two-thirds of the fibula’s lateral surface and inserts onto the base of the fifth metatarsal bone. The affected muscle normally aids in which of the following foot movements?
A
Lateral rotation
B
Eversion
C
Dorsiflexion
D
Inversion
E
Medial rotation
This movement would be impaired if the superficial peroneal nerve was injured.
B
Eversion
The peroneus brevis muscle, located in the lateral compartment of the leg, is primarily responsible for eversion of the foot and assists in plantarflexion of the foot. Injury manifests primarily with impaired foot eversion while plantarflexion may be normal or weak. Rupture of the tendon is an uncommon severe complication of fluoroquinolones (e.g., levofloxacin), particularly in older patients.
A 13-year-old African American girl is brought to the physician for right shoulder pain that has worsened over the past month. She has had many episodes of joint and bone pain and, as a young child, recurrent painful swelling in her hands and feet. Physical examination shows tenderness of the right anterior humerus without swelling or skin changes. Active and passive range of motion of the right shoulder is decreased and there is pain with movement. The leukocyte count is 4600/mm3. An x-ray of the right shoulder shows subchondral lucency of the humeral head with sclerosis and joint space narrowing. Which of the following is the most likely underlying cause of this patient’s shoulder pain?
A
Infection of the joint space
B
Crystal deposition within the joint
C
Loss of bone mineral density
D
Infarction of the bone trabeculae
E
Infection of the bone
This adolescent African American girl presents with a history of episodic joint and bone pain and dactylitis, all of which suggest sickle cell disease (SCD). The x-ray findings are consistent with a complication of this disease.
D
Infarction of the bone trabeculae
69%
Infarction of trabecular bone is characteristic of avascular necrosis, which is most likely due to underlying SCD in this patient and has resulted in gradual onset of constant pain and decreased range of motion. This patient’s radiologic findings (subchondral lucency secondary to microfractures, sclerosis, joint space narrowing) are common in advanced avascular osteonecrosis. Her episodes of hand and foot swelling as a child are typical for dactylitis (due to bone infarction from SCD), which is characterized by a moth-eaten appearance of the bones on x-ray.
A 57-year-old woman with type 2 diabetes mellitus comes to the physician for a follow-up examination. She previously had been adherent to her diet and medication but has had a 5-kg (11-lb) weight gain since the last visit 6 months ago. She reports that she often misses doses of her metformin. Her hemoglobin A1c is 9.8%. Which of the following is the most appropriate initial action by the physician?
A
Refer the patient to a dietician
B
Schedule more frequent follow-up visits
C
Refer the patient to an endocrinologist
D
Add glyburide to the medication regimen
E
Stop metformin and begin an insulin regimen
This patient has a markedly elevated hemoglobin A1c as a result of poorly controlled type 2 diabetes mellitus. Improving medication adherence is critical to preventing future complications.
B
Schedule more frequent follow-up visits
77%
This patient’s poor medication adherence is the most likely cause of her poorly-controlled diabetes, but the cause of her nonadherence is unclear at this point. Employing strategies that aim to strengthen the doctor-patient relationship and therapeutic alliance, such as scheduling frequent follow-up visits, and a patient-centered approach often improve patients’ medication adherence. Frequent follow-up visits also enable closer monitoring of the patient’s medication use. Other strategies to improve medication adherence include providing written instructions, optimizing the treatment plan (e.g., prescribing once-daily scheduled medications when possible), and using the teach-back method.
A 53-year-old man comes to the physician because of a 2-week history of fatigue, generalized itching, and yellowing of the eyes and skin. He underwent a liver transplantation because of acute liver failure following α-amanitin poisoning 1 year ago. Physical examination shows scleral icterus and abdominal distention with shifting dullness. A liver biopsy specimen shows decreased hepatic duct density. Further histological examination of the liver biopsy specimen is most likely to show which of the following findings?
A
Graft vessel vasculitis
B
Neoplastic cells containing bile
C
Fibrinoid necrosis
D
Interstitial fibrosis
E
Viral inclusions
This patient with a history of liver transplantation is now exhibiting features of liver failure (jaundice, pruritus, fatigue, ascites). Biopsy shows ductopenia, which indicates vanishing bile duct syndrome.
D
Interstitial fibrosis
49%
Signs and symptoms of liver failure one year after liver transplantation suggests chronic graft rejection, which occurs due to reactions at both the cellular and humoral level in response to donor peptides. The ensuing inflammation leads to interstitial fibrosis, atrophy of the parenchyma, vascular smooth muscle proliferation, and ductopenia (as seen on this patient’s biopsy).
Forty minutes after undergoing nasal polypectomy for refractory rhinitis, a 48-year-old woman develops chest tightness and shortness of breath. The surgical course was uncomplicated, and the patient was successfully extubated. She received ketorolac for postoperative pain. A similar episode happened 6 months ago after the patient took aspirin for a headache; symptoms resolved spontaneously within 3 hours. She has a history of asthma and hypertension. Her daily medications include metoprolol and lisinopril. Examination shows a flushed face, watery rhinorrhea, and conjunctival injection. Chest auscultation reveals bilateral wheezing and decreased breath sounds. An ECG shows no abnormalities. Which of the following is the most likely underlying cause of this patient’s symptoms?
A
Type 1 hypersensitivity reaction
B
Prinzmetal angina
C
Pseudoallergic reaction
D
Excessive beta-adrenergic blockade
E
Bradykinin-induced bronchial irritation
Chronic rhinosinusitis with nasal polyposis, NSAID hypersensitivity, and asthma constitutes Samter triad.
C
Pseudoallergic reaction
39%
Samter triad is a feature of aspirin-exacerbated respiratory disease (AERD). Patients with AERD develop symptoms resembling those of a type 1 hypersensitivity reaction (e.g., wheezing, decreased breath sounds, facial flushing) following the administration of aspirin or NSAIDs (e.g., ketorolac). Watery rhinorrhea and conjunctival injection are also commonly seen in AERD. Unlike a type 1 hypersensitivity reaction, which is an IgE-mediated process, AERD is a pseudoallergic reaction caused by the inhibition of cyclooxygenase (COX). Inhibition of the COX pathway increases the conversion of arachidonic acid to leukotrienes via the lipoxygenases pathway. Leukotrienes cause cutaneous flushing and bronchial inflammation.
A 60-year-old man is brought to the emergency department because of a 1-hour history of disorientation and slurred speech. He has a 10-year history of hypertension and hypercholesterolemia. His blood pressure is 210/110 mm Hg, and pulse is 90/min. Once the patient is stabilized, an MRI of the brain is performed, which shows an infarct of the left precentral gyrus involving the region that supplies the facial nerve. Given the MRI findings, which of the following neurological findings would most be expected?
A
Loss of taste in the posterior third of the right half of the tongue
B
Flattening of the right nasolabial fold
C
Decreased lacrimation of the left eye
D
Drooping of the left eyelid
E
Hyperacusis of the left ear
F
Inability to raise the right eyebrow
A lesion of the corticobulbar tract between the precentral gyrus and the brainstem nuclei of the facial nerve causes central facial nerve palsy.
B
Flattening of the right nasolabial fold
34%
Flattening of the right nasolabial fold would be expected in central facial nerve palsy. The facial motor nucleus has two regions: one that supplies the muscles of the forehead and a second that supplies the rest of the face. The branches of the facial nerve that innervate the forehead are activated by both cerebral hemispheres, whereas the branches innervating the lower portion of the face are only activated by the contralateral cerebral hemisphere. As a result, the forehead is spared with unilateral infarction of the precentral gyrus, while the contralateral lower face becomes paralyzed.
A previously healthy 52-year-old woman comes to the physician because of a 1-week history of productive cough, fevers, and malaise. She has smoked one pack of cigarettes daily for 35 years. Her temperature is 39.0°C (102.2°F). Diffuse inspiratory crackles are heard bilaterally. Her leukocyte count is 14,300/mm3. Sputum analysis shows numerous polymorphonuclear leukocytes and a few squamous epithelial cells. An x-ray of the chest shows bilateral patchy consolidations. Which of the following findings on sputum culture is most consistent with this patient’s respiratory symptoms?
A
Encapsulated, pleomorphic, gram-negative coccobacilli
B
Gram-positive, catalase-positive, coagulase-negative cocci in clusters
C
Anaerobic gram-positive, branching, filamentous bacilli
D
Pseudohyphae with budding yeasts at 20°C
E
Aerobic, gram-positive bacilli with metachromatic granules
F
Gram-positive, alpha-hemolytic, optochin-resistant cocci in chains
This patient has manifestations of typical bronchopneumonia, which include a productive cough, fever, malaise, leukocytosis, diffuse bilateral crackles on auscultation, and bilateral patchy consolidations on imaging.
A
Encapsulated, pleomorphic, gram-negative coccobacilli
36%
Haemophilus influenzae is an encapsulated, pleomorphic, gram-negative coccobacillus that commonly causes community-acquired pneumonia. It is a normal component of the upper respiratory tract flora of healthy adults. Most infections caused by H. influenzae are caused by nontypeable strains. Patients with underlying lung disease (e.g., chronic obstructive pulmonary disease in this woman with a 35 pack-year smoking history) are more susceptible to infection. H. influenzae pneumonia is typically less severe than bacterial pneumonia caused by Streptococcus pneumoniae, which is the most common cause of pneumonia in adults.
A 2-week-old newborn is brought to the physician because of worsening feeding difficulty since birth. Examination shows a grade 2/6 harsh holosystolic murmur, heard most clearly at the left lower sternal border, and a soft mid-diastolic rumble over the cardiac apex. Echocardiography shows shunting of blood through the ventricular septum during systole. The patient undergoes surgery for closure of the defect. Which of the following sets of changes are expected after successful repair of this cardiac defect?
Left atrial pressure Left ventricular pressure Right ventricular pressure
A ↓ ↑ no change
B ↓ ↑ ↓
C ↑ ↑ ↑
D ↓ ↓ ↓
E ↑ ↑ ↓
B
A VSD causes left-to-right shunting of blood because the left ventricular pressure is physiologically higher than the right ventricular pressure due to the thicker ventricular wall and higher force of contraction. Closure of a VSD would, therefore, increase the amount of blood in the left ventricle and decrease the amount of blood in the right ventricle during each cardiac cycle. This results in an increase in left ventricular pressure and a decrease in right ventricular pressure as well as right ventricular output, which translates to a decrease in the amount of blood flowing into the left atrium and therefore a decrease in left atrial pressure.
A 38-year-old man comes to the physician because of persistent sadness and difficulty concentrating for the past 6 weeks. During this period, he has also had difficulty sleeping. He adds that he has been “feeling down” most of the time since his girlfriend broke up with him 4 years ago. Since then, he has only had a few periods of time when he did not feel that way, but none of these lasted for more than a month. He reports having no problems with appetite, weight, or energy. He does not use illicit drugs or alcohol. Mental status examination shows a depressed mood and constricted affect. Which of the following is the most likely diagnosis?
A
Major depressive disorder
B
Bipolar affective disorder
C
Cyclothymic disorder
D
Persistent depressive disorder
E
Adjustment disorder with depressed mood
This patient’s symptoms have been present for most days over the past 4 years without a symptom-free period > 2 consecutive months, providing a clue to the diagnosis.
D
Persistent depressive disorder
71%
This patient presents with a depressed mood, difficulty sleeping, and poor concentration, which is causing psychosocial impairment. These symptoms have been present for more days than not for the past 4 years in the absence of substance use, and the patient was not asymptomatic for > 2 consecutive months during this time. Accordingly, he meets the criteria for persistent depressive disorder (dysthymia). He would likely benefit from treatment with an SSRI and/or psychotherapy.
A 71-year-old woman with type 2 diabetes mellitus and hypertension comes to the emergency department because of a 3-day history of intermittent abdominal pain, vomiting, and obstipation. She has had multiple episodes of upper abdominal pain over the past year. She has smoked one pack of cigarettes daily for the past 30 years. Physical examination shows a distended abdomen with diffuse tenderness and high-pitched bowel sounds. An x-ray of the abdomen shows a dilated bowel, multiple air-fluid levels, and gas in the biliary tree. Which of the following is the most likely cause of this patient’s condition?
A
Perforation of a peptic ulcer
B
Inflammation of the gallbladder wall
C
Obstruction of the common bile duct
D
Occlusion of the superior mesenteric artery
E
Torsion of the large intestine
This patient with a long-standing history of episodic upper abdominal pain now presents with features of mechanical obstruction (abdominal distention, vomiting, obstipation, high-pitched bowel sounds, and dilated bowel loops with multiple air-fluid levels) with pneumobilia on abdominal x-ray.
Inflammation of the gallbladder wall
26%
Chronic inflammation of the gallbladder wall can lead to the formation of an abnormal connection between the gallbladder and the intestinal tract (i.e., a cholecystoenteric fistula), which provides a conduit for the passage of gallstones. A gallstone can subsequently become lodged in the distal ileum, the section of the intestine with the narrowest lumen, causing gallstone ileus. An abdominal x-ray will show pneumobilia, indicating that intraintestinal air has moved through to the fistula into the biliary tree.
Treatment for gallstone ileus is usually surgical, involving removal of the stone (enterolithotomy) and possibly bowel resection to relieve the intestinal obstruction.
A 47-year-old woman comes to the physician because of fatigue and body aches for the past 9 months. She also has stiffness of the shoulders and knees that is worse in the morning and tingling in the upper extremities. Examination shows marked tenderness over the posterior neck, bilateral mid trapezius, and medial aspect of the left knee. A complete blood count and erythrocyte sedimentation rate are within the reference ranges. Which of the following is the most likely diagnosis?
Dysregulation of the neuroendocrine and autonomic nervous systems is thought to play a role in the pathogenesis of this condition.
Fibromyalgia
67%
Fibromyalgia, a condition that most commonly develops among women 20–50 years of age, is characterized by fatigue and diffuse musculoskeletal pain and stiffness affecting all or most regions of the body (traditionally referred to as “tender points” of fibromyalgia). Other features that may be present in patients with fibromyalgia include paresthesias, headache, unrefreshing sleep, cognitive dysfunction (“fibro fog”), and autonomic dysfunction. CBC and ESR are typically normal in patients with this condition. Fibromyalgia is associated with comorbidities such as tension headaches, sleep disturbances, anxiety disorder, chronic fatigue syndrome, depression, and irritable bowel syndrome. First-line therapies for fibromyalgia include nonpharmacologic interventions such as patient education, dietary changes, sleep hygiene, and regular physical activity.
A 13-year-old boy is brought to the emergency department by ambulance after suddenly losing consciousness while playing in a soccer tournament. The patient has had 2 episodes of syncope without a discernable trigger over the past year. He has been otherwise healthy. His father died suddenly at the age of 37. He reports lightheadedness and suddenly loses consciousness when physical examination is attempted. Radial pulses are not palpable. An ECG shows ventricular tachycardia with peaks of the QRS twisting around the isoelectric line. Which of the following is the most likely underlying cause of this patient’s condition?
A
Anomalous origin of the left coronary artery
B
Accessory atrioventricular conduction pathway
C
Myofibrillar disarray of cardiac septum
D
Bicuspid aortic valve
E
Defect in interatrial septum
F
Mutation of myocardial potassium channels
Torsades de pointes arrhythmia on ECG (peaks of the QRS twisting around the isoelectric line), a history of unexplained syncope, and a suspected family history of sudden cardiac death are most concerning for Romano-Ward syndrome.
F
Mutation of myocardial potassium channels
48%
Torsades de pointes is most often due to long QT syndrome, which may be acquired or congenital. Congenital long QT syndrome can be caused by mutations of genes coding for cardiac potassium, sodium, or calcium ion channels. These mutations cause ventricular action potentials to be prolonged, leading to a lengthened QT interval on ECG. The two most common long QT syndromes are Romano-Ward syndrome and Jervell and Lange-Nielsen (JLN) syndrome.
Jervell and Lange-Nielsen (JLN) syndrome follows an autosomal recessive pattern of inheritance and is associated with congenital deafness. Romano-Ward syndrome follows an autosomal dominant pattern of inheritance and is not associated with deafness.
Incorrect:C
Myofibrillar disarray of cardiac septum
24%
Myofibrillar disarray of the cardiac septum is a feature of hypertrophic cardiomyopathy (HCM), which is a common cause of sudden cardiac death in young athletes, and can present with dyspnea, dizziness, and syncope, as seen in this patient. Furthermore, it should be suspected in a patient with a family history of sudden cardiac death, as it follows an autosomal dominant pattern of inheritance in approx. 50% of cases. However, HCM is unlikely to cause torsades de pointes arrhythmia.
A 73-year-old man is brought to the emergency department because of fever, malaise, dyspnea, and a productive cough with purulent sputum for the past day. His temperature is 39.2°C (102.6°F). Pulmonary examination shows crackles over the right upper lung field. Sputum Gram stain shows gram-positive cocci. Despite the appropriate treatment, the patient dies 5 days later. At autopsy, gross examination shows that the right lung has a pale, grayish-brown appearance and a firm consistency. Microscopic examination of the tissue is most likely to show which of the following?
A
Fibrinopurulent leukocytic exudate with lysed erythrocytes
B
Fibrinous exudate with erythrocytes, leukocytes, and bacteria
C
Resorbed exudate with aerated alveoli
D
Neutrophilic infiltrate in the bronchiolar walls and adjacent alveoli
E
Dilation of alveolar capillaries and serous exudate with abundant bacteria
The patient died of pneumonia, most likely due to Streptococcus pneumoniae (a gram-positive coccus), the most common cause of lobar pneumonia. The gross appearance of the lung (pale, gray, and consolidated) corresponds with the stage of gray hepatization, which typically occurs during days 5–7 of lobar pneumonia.
Fibrinopurulent leukocytic exudate with lysed erythrocytes
45%
Fibrinopurulent leukocytic exudate with lysed erythrocytes is the classic finding in the gray hepatization stage of pneumonia. Lobar pneumonia progresses through discrete stages that can be seen on histopathological examination, with gray hepatization arising between days 5 and 7. The lung appears grayish-brown with a yellow tinge due to fibrinopurulent exudate; this fibrinous buildup also explains the firm consistency of the ordinarily spongy parenchyma. Disintegration of extravasated red cells and subsequent hemosiderin deposition is responsible for the brownish color.
Incorrect:
B
Fibrinous exudate with erythrocytes, leukocytes, and bacteria
Fibrinous exudate with erythrocytes, leukocytes, and bacteria describes the microscopic appearance of red hepatization. These findings are classically observed 3–4 days into the progression of pneumonia as a result of inflammatory damage to the fragile pulmonary microvasculature. The early stages of fibrin deposition are a response to these vascular injuries and the quantity is sufficient to change the gross consistency of the lung (hence the name hepatization). This patient died at a more advanced stage of the infection, which means that a more drastic change in microscopic anatomy would be expected.
A 3-week-old boy is brought to the physician for the evaluation of poor feeding and recurrent episodes of vomiting. He was delivered at term after an uncomplicated pregnancy. He is at the 5th percentile for length and weight. Physical examination shows generalized hypotonia. Urinalysis shows increased propionic acid concentration. The finding on urinalysis is best explained by the breakdown of which of the following substances?
C
Branched-chain amino acids
Propionyl-CoA is generated by the catabolism of the amino acids threonine, methionine, isoleucine, and valine. Of these amino acids, isoleucine and valine are branched-chain amino acids. Propionyl-CoA is also generated by the catabolism of odd-chain fatty acids, cholesterol, and the pyrimidines thymine and uracil. Propionyl-CoA carboxylase converts propionyl-CoA to methylmalonyl-CoA, which is converted to succinyl-CoA by methylmalonyl-CoA mutase. Succinyl-CoA generates oxaloacetate via the TCA cycle, which can be used to generate glucose (gluconeogenesis). A deficiency of propionyl-CoA carboxylase or methylmalonyl-CoA mutase can, therefore, cause symptoms of hypoglycemia (e.g., muscular hypotonia, vomiting, and lethargy), failure to thrive, and HAGMA due to the accumulation of propionic acid, which is subsequently excreted in urine.
A 28-year-old nulligravid woman comes to the physician for a routine health maintenance examination. Upon questioning, she reports that she and her husband have been trying to conceive for more than 1 year; they have unprotected sexual intercourse 3–4 times per week. Recently, she has not been enjoying sexual intercourse with her husband because of painful penetration. She also reports episodic back and pelvic pain over the past 6 months that lasts for 2–3 days; she has missed several days of work each month because of the pain. Menarche was at the age of 13 years, and menses occur at 26–28 day intervals and last 3 days with normal flow. Pelvic examination shows a normal-appearing vulva and vagina. There is rectovaginal tenderness. Ultrasonography of the pelvis shows a retroverted normal-sized uterus. Further evaluation is most likely to show which of the following findings?
A
Endometrial tissue within the myometrium on biopsy
B
Polycystic ovaries on ultrasonography
C
Reddish-blue peritoneal lesions on laparoscopy
D
Concentric, solid myometrial tumors on MRI
E
Intracellular organisms on endocervical culture
The patient’s infertility, dyspareunia, and cyclic pelvic pain suggest endometriosis.
C
Reddish-blue peritoneal lesions on laparoscopy
51%
Endometriosis is a gynecological condition affecting reproductive-aged women characterized by ectopic endometrial tissue. Patients commonly present with cyclic pelvic pain, dysmenorrhea, dyspareunia, as well as infertility. Preliminary diagnosis of endometriosis is typically based on the patient’s history, since most women have a normal physical examination. However, the most common findings include tenderness on palpation of the posterior vaginal fornix (i.e., rectovaginal tenderness) and a retroverted fixture (due to adhesions). Diagnosis is confirmed by laparoscopic visualization of endometrial implants outside the uterine cavity (e.g., peritoneal lesions with a reddish-blue appearance), with histological examination of biopsy specimens typically showing hemosiderin-laden macrophages with normal endometrial epithelium.
A 51-year-old woman comes to the physician because of a 1-year history of occasional discoloration and tingling in her fingers. She has no history of major medical illness and takes no medications. Examination of the hands and fingers shows thickened, waxy skin and several firm white nodules on the fingertips. Further evaluation of this patient is most likely to show which of the following findings?
A
Serositis
B
Upper eyelid rash
C
Telangiectasia
D
Endocardial immune complex deposition
E
Collagen deposition in kidney parenchyma
F
Interstitial lung disease
This patient’s history of periodic finger discoloration and paresthesia is suggestive of Raynaud phenomena; physical examination shows sclerodactyly and calcinosis cutis. Together, these clinical features are suggestive of limited systemic sclerosis (LcSSc), a condition most common among middle-aged women.
C
Telangiectasia
58%
Telangiectasia is seen in lcSSc, which often presents as a combination of 5 clinical features called CREST syndrome, named after its principal clinical manifestations: calcinosis cutis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia. This patient may also experience signs of esophageal dysmotility (e.g., dysphagia) in the future.
Unlike diffuse cutaneous systemic sclerosis (dcSSc), lcSSc typically lacks proximal limb and truncal skin involvement. Other findings, such as significant renal, interstitial lung, or myocardial disease, as well as arthralgias and myalgias, are also common in dcSSC but not in lcSSc.
