04-3 Gen Surg: Endocrine Flashcards
A 62-year-old woman was drinking her morning cup of coffee at the same time she was applying her makeup, and she noticed in the mirror that there was a lump in the lower part of the neck, visible when she swallowed. She consults you for this, and on physical examination you ascertain that she indeed has a prominent, 2-cm mass on the left lobe of her thyroid as well as two smaller
masses on the right lobe. They are all soft, and she has no palpable lymph nodes in the neck.
Management. Most thyroid nodules are benign, and surgical removal to ascertain the diagnosis is a big operation—thus surgery has to be reserved for selected cases. Worrisome features include: young, male, single nodule, history of radiation to the neck, solid mass on sonogram, and cold nodule on scan. In centers with sufficient experience, the last two tests are omitted in preference for FNA and cytology. This case does not sound malignant, but you cannot be sure. If given the option among the answers, go for the FNA.
A 21-year-old man is found on a routine physical examination to have a single, 2-cm nodule in the thyroid gland. His thyroid function tests are normal. An FNA is read as indeterminate.
Management. Surgery is done for the FNAs that are read as malignant and those that are indeterminate.
A 32-year-old woman has a thyroid lobectomy done for a 2-cm mass that had been reported on a FNA as a “follicular neoplasm, not otherwise specified.”
The specimen is given for frozen section to a pathologist with a great deal of experience in thyroid disease and in the reading of frozen sections. The intraoperative diagnosis is follicular cancer.
Management: A total thyroidectomy should be completed.
An automated blood chemistry panel done during the course of a routine medical examination indicates that an asymptomatic patient has a serum calcium of 12.1 in a lab where the upper limit of normal is 9.5. Repeated determinations are consistently between 10.5 and 12.6. Serum phosphorus is low.
What is it? Parathyroid adenoma.
Diagnosis. Had this question been written 20 years ago, the vignette would have described a patient with a disease of “stones and bones and abdominal groans,” and you would have cleverly asked for a serum calcium as your first test. Nowadays most parathyroid adenomas are identified when they are still asymptomatic, because of the widespread use of automated blood chemistry
panels. Across the board, most cases of hypercalcemia are caused by metastatic cancer, but that would not be the case on asymptomatic people. Your next move here is parathyroid hormone (PTH) determination and sestamibi scan to localize the adenoma. Surgery will follow.
A 32-year-old woman is admitted to the psychiatry unit because of wild mood swings. She is found to be hypertensive and diabetic and to have osteoporosis.
(She had not been aware of such diagnosis beforehand.) It is also ascertained that she has been amenorrheic and shaving for the past couple of years. She has gross centripetal obesity, with moon facies and buffalo hump, and thin, bruised extremities. A picture from 3 years ago shows a person of very different, more normal appearance.
What is it? Cushing. The appearance is so typical that you will probably be given before and after photographs on the test, with an accompanying brief vignette. The presenting symptom may be any one of those listed.
Diagnosis. Start with the overnight dose dexamethasone suppression test. If she suppresses at a low dose, she is an obese, hairy woman, but she does not have the disease. If she does not suppress at the low dose, verify that 24-hour urine-free cortisol is elevated, and then go to high-dose suppression tests. If she suppresses at a high dose, do an MRI of the head looking for the pituitary
microadenoma, which will be removed by the transnasal, trans-sphenoidal route. If she does not suppress at the higher dose, do a CT or MRI of adrenals looking for the adenoma there. The Mayo Clinic advocates a different diagnostic algorithm, where the diagnosis of Cushing disease is established by 24-hour urinary collection for free cortisol levels (patients with this disease have
levels three to four times the normal) and relies on measurement of corticotropin to differentiate pituitary adenomas from adrenal adenomas. 6. A 28-year-old woman has virulent peptic
A 28-year-old woman has virulent peptic ulcer disease. Extensive medical management including eradication of Helicobacter pylori fails to heal her ulcers. She has several duodenal ulcers in the first and second portions of the duodenum. She has watery diarrhea.
What is it? Gastrinoma (Zollinger-Ellison).
Diagnosis. Start by measuring serum gastrin. If the value is not clearly normal or abnormal, a secretin stimulation test is added. Later CT scans (with vascular and GI contrast) of the pancreas and nearby areas to find the tumor, and surgery to remove it.
A second-year medical student is hospitalized for a neurologic workup for a seizure disorder of recent onset. During one of the convulsions, it is determined that his blood sugar is extremely low. Further workup shows that
he has high levels of insulin in the blood with low levels of C-peptide.
What is it? Exogenous administration of insulin. If the C-peptide had been high along with the insulin level, the diagnosis would have been insulinoma. Had it been a baby with high insulin levels and low blood sugar, nesidioblastosis.
Management. In this case, psychiatric evaluation and counseling (he is faking the disease to avoid taking the USMLE). If it had been insulinoma, CT scan (with vascular and GI contrast) looking for the tumor in the pancreas, to be subsequently removed surgically. The babies with
nesidioblastosis need 95% pancreatectomy.
A 48-year-old woman has had severe, migratory necrolytic dermatitis for several years, unresponsive to all kinds of “herbs and unguents.” She is thin and has mild stomatitis and mild diabetes mellitus.
What is it? Glucagonoma.
Diagnosis. Determine glucagon levels. Eventually CT scan (with vascular and GI contrast) looking for the tumor in the pancreas. Surgery will follow. If inoperable, somatostatin can help symptomatically, and streptozocin is the indicated chemotherapeutic agent.
A 45-year-old woman comes into your office for a regular checkup. On repeated determinations you confirm the fact that she is hypertensive. When she was in your office 3 years ago, her blood pressure was normal. Laboratory
studies at this time show a serum sodium of 144 mEq/L, a serum bicarbonate of 28 mEq/L, and a serum potassium concentration of 2.1 mEq/L. The woman is taking no medications of any kind.
What is it? Hyperaldosteronism. Possibly adenoma.
Diagnosis. Start with determination of aldosterone and renin levels. If confirmatory (aldosterone high, renin low), proceed with determinations lying down and sitting up to differentiate hyperplasia (appropriate response to postural changes—not surgical) from adenoma (no
response or wrong response to postural changes—surgical). Treat the first with Aldactone. Pursue the second with imaging studies (CT or MRI) and surgery.
A thin, hyperactive 38-year-old woman is frustrated by the inability of her physicians to help her. She has episodes of severe pounding headache, with palpitations, profuse perspiration, and pallor, but by the time she gets to her doctor’s office she checks out normal in every respect. In addition, she has paroxismal hypertension.
What is it? Suspect pheochromocytoma.
Diagnosis. The most sensitive test is the 24-hour urinary metanephrine test (90% effective). The vanillylmandelic acid (VMA) test is next best, at 80% effective. Follow with CT scan of adrenal glands. Surgery will eventually be done, with careful pharmacologic preparation with alpha-blockers.
A 17-year-old man is found to have a blood pressure of 190 over 115. This is checked repeatedly in both arms, and it is always found to be elevated, but when checked in the legs it is found to be normal.
What is it? Coarctation of the aorta.
Diagnosis. Start with a chest x-ray, looking for scalloping of the ribs. Then noninvasive fancy spiral CT enhanced with intravenous dye (CT angio), and ultimately surgery.
I. A 23-year-old woman has had severe hypertension for 2 years, and she does not respond well to the usual medical treatment for that condition. A bruit can be faintly heard over her upper abdomen.
II. A 72-year-old man with multiple manifestations of arteriosclerotic occlusive disease has hypertension of relatively recent onset and refractory to the usual medical therapy. He has a faint bruit over the upper abdomen.
What are they? Two examples of renovascular hypertension; the first one caused by fibromuscular
dysplasia, the second one secondary to arteriosclerosis.
Diagnosis. Start with Duplex scanning of the renal vessels. CT angio may also be helpful.
Management. Once the diagnosis has been made, the decision for therapy is easy in the young lady: she has many years of potential life, and her hypertension must be cured. Angiographic balloon dilation with stenting is the first choice, surgery the other alternative. In the elderly man the decision is far more complex. Treatment of the renovascular hypertension makes sense only if other manifestations of the arteriosclerosis are not going to kill him first.
