Surgery Medical School Crash Course (Unabridged) - 11 A_T_F

This chapter focuses on surgery for endocrine organs, specifically the thyroid gland and adrenal glands. A total thyroidectomy is a safe procedure, and there are various reasons for its removal such as thyroid nodules, hyperthyroidism, obstructive goiter, and thyroid cancers. Preoperative evaluation includes imaging, lab tests, and laryngeal examination. Antithyroid medications and Lugol's solution may be given before surgery. Complications like infection and nausea can be managed with antibiotics and dexamethasone. Thromboembolism prevention and anesthesia options are discussed. The surgical procedure involves making an incision, removing the thyroid gland, and protecting nerves and blood vessels. The extent of resection depends on the disease being treated. Lymph node removal may be necessary in certain cases. Chapter 8, Endocrine Surgery. This chapter is devoted to surgery on endocrine organs. There are many endocrine organs in the body, but many do not require any type of removal. The two main endocrine organs that need to be removed for various reasons in the body include the thyroid gland and the adrenal glands. These will be the two endocrine glands that will be discussed from a surgical perspective. Surgical Thyroidectomy. In the past, thyroid surgery used to be dangerous, but there have been many new surgical improvements over the years, so actually a total thyroidectomy is a safe procedure, especially when done by a surgeon who specializes in endocrine surgery. Removal of the thyroid gland can be done for nonmalignant or malignant reasons. Regardless of the reason for the surgery, there are many things that need to be done to prepare for surgery, a number of surgical options, and important things that must be done postoperatively to avoid complications. There are several reasons why a total thyroidectomy needs to be performed. Thyroid nodules may be removed separately or may be multifocal, requiring a total thyroidectomy. Hyperthyroidism can be managed medically or can be managed using medical treatments or surgical therapy. An obstructive goiter that is interfering with swallowing is treated with a thyroidectomy. Differentiated papillary or follicular thyroid cancers are usually managed by removing the thyroid gland. Medullary cancer and anaplastic thyroid cancers are removed surgically, as is thyroid lymphoma, which is only treated by having a thyroid biopsy and doing both radiotherapy and chemotherapy on the organ. Any metastases to the thyroid gland, usually coming from renal cell cancer or melanoma, is generally treated by removing the thyroid gland. Post-thyroid surgery isn't emergent and is instead elective. This gives the surgeon and the patient time to get surgical and medical issues in order before removing the thyroid gland. This means that preoperative imaging can be done, lab testing can be done, and an evaluation of the larynx can be done. Thyroid imaging includes a diagnostic thyroid ultrasound, which is done on all patients with nodules or suspicious lesions on the thyroid gland. An ultrasound is done on both lobes, as well as on cervical lymph nodes, to check for metastases in malignant conditions. Sometimes CT or MRI scanning is done in patients who have advanced disease, but the ultrasound is the gold standard of imaging of the thyroid gland. The lab tests important in preoperative evaluation of the thyroid gland include a serum thyroid-stimulating hormone, or TSH level, to see if the patient has normal thyroid functioning, hyperfunctioning of the thyroid gland, or hypofunctioning of the thyroid gland. A serum calcium level can be done on patients who have suspected parathyroid problems. Patients with medullary thyroid cancer need a serum calcitonin level, a carcinoembryonic antigen or CEA level, genetic testing for germline Rett mutations, and an evaluation for other endocrine problems that might be present, such as hyperparathyroidism and a pheochromocytoma. Unfortunately, medullary thyroid cancer can be genetic as part of multiple endocrine neoplasia type 2 or MEN2A disease. A laryngeal exam is always done if thyroid surgery is necessary to see if there is normal functioning of the vocal cords. A direct or indirect laryngoscopy is performed to see what the vocal cords look like. A unique test called a video stroboscopy can be done, revealing a slow-motion, magnified image of the vocal cords, along with an ultrasound of the vocal cords. Sometimes the recurrent laryngeal nerve is damaged in thyroid surgery, so it pays to see if the vocal cords are working before doing surgery. Patients with paralysis of the vocal cords will have hoarseness, previous neck surgery, extension of a malignancy into the nerve or large lymph nodes pressing on the recurrent laryngeal nerve. Invasive thyroid cancer may result in paralysis of the vocal cords by extension into the recurrent laryngeal nerve. This can be diagnosed by doing a laryngoscopy or other procedure to demonstrate that the cancer has invaded into the nerve and has already paralyzed one or both vocal cords. Unfortunately, this can be a hidden problem, so even patients who appear normal should have this evaluation. If the patient is found to be hyperthyroid and needs thyroid surgery, they should receive antithyroid medications or a beta blockade with a beta blocker like propranolol so they won't have a preoperative thyroid storm. Lugol's solution, which contains potassium iodide, will block iodine uptake and will block the secretion of thyroid hormones. It also had the effect of reducing the thyroid vascularity so there is less bleeding during surgery. It is also wise to give calcium and vitamin D because patients can be hypocalcemia after surgery and this can prevent the problem. Patients who have had previous thyroid surgery might need reoperative surgery to the thyroid gland or even who have had neck surgery for other reasons. This can be challenging because there are often adhesions and scar tissue formation that will make the laryngeal surgery more complicated and may lead to hypoparathyroidism or recurrent laryngeal nerve injury that will happen more often with reoperative surgery to the neck, particularly to the thyroid gland. Sometimes, the patient will have part of the thyroid gland removed because of thyroid cancer and will need to go on to having a complete thyroidectomy later. Ideally, it should be done within a week of the first surgery to make sure that the surgery is done before inflammation has set in the thyroid gland. If there is too much inflammation, the surgery should be delayed by six weeks. There is a low rate of infection in thyroid surgery because the blood supply is so good. Even so, antibiotics like cephalosporins need to be given to patients at risk for wound infections or who are immunocompromised and might have an infection after surgery. The ideal is to give the antibiotic as a single dose within an hour of surgery. Dexamethasone is given as a single dose before surgery because many patients with thyroid surgery have nausea that can be effectively managed by giving them this drug. There are other drugs that can be given if nausea occurs, but dexamethasone is the treatment of choice in patients who might get nauseous after surgery. Typical prophylaxis after any surgery involves using mechanical interventions for prevention of thromboembolism. This includes the use of sequential compression devices and the encouragement of early ambulation after surgery to get the blood flowing in the deep veins of the legs. Thyroid surgery can be done under either local, regional, or general anesthesia. Most are done under general anesthesia with endotracheal intubation. When local anesthesia is performed, the patient can talk to the surgical staff so that they can make sure the vocal cords are continually working. A cocker or collar incision is made during surgery in the front of the mid-neck of the patient. Ideally, it should be placed in an area of an existing crease in the skin. The length of the incision should be based on the size of the thyroid gland that is to be removed. If the gland is big or the patient is very large, a longer incision is necessary. The area is dissected down to the platysma muscle, and this is divided into two flaps. The strap muscles need to be opened in the midline of the neck. Any enlarged lymph nodes should be removed, as they often contain metastatic disease. If the thyroid tumor is adherent or otherwise stuck to the strap muscles, those parts of the strap muscles should be removed along with the entire tumor and remainder of the thyroid gland. Starting in the midline, one lobe of the gland is dissected away from the neck, from the middle to the outside. The middle thyroid vein should be ligated, and the backside of the thyroid gland should be visible. The arteries to the thyroid gland are ligated, and then the external branch of the superior laryngeal nerve should be identified and protected. The recurrent laryngeal nerve should be isolated in the tracheoesophageal groove and protected from harm. All blood vessels should be ligated so the thyroid lobes can be lifted off the neck, including the capsule, including the capsule. The isthmus is separated so that the other lobe can be removed in the same way as the first lobe. All specimens are sent for pathology. If there is adequate hemostasis, the platysma muscle is closed, and the skin is sutured or stapled. The extent of resection depends on what disease is being treated. A total thyroidectomy is recommended for patients with thyroid cancer, including differentiated thyroid cancer and medullary thyroid cancer. Graves' disease should be managed with a total thyroidectomy. If the cancer is low-risk and well-differentiated, only a lobe needs to be removed. Any differentiated thyroid cancer less than a centimeter and localized to one lobe can be treated with a thyroid lobectomy. Removal of just thyroid nodules are not recommended as patients are predisposed to have a recurrence of disease. Sometimes the lymph nodes need to be removed at the time of thyroid surgery, depending on the type of malignancy and the risk of lymph node metastases. Patients with follicular, papillary, or medullary thyroid cancer and radiological evidence of enlarged lymph nodes should have a therapeutic lymphadenectomy at the time of surgery. A prophylactic lymphadenectomy should be performed under the following circumstances. Patients with medullary thyroid cancer should have the central compartment nodes removed, even if they show no evidence of cancer. Patients with papillary cancer should have preventative removal of the central lymph nodes if the cancer is bigger than 4 centimeters in diameter or if the tumor has moved past the thyroid tissue. Follicular thyroid cancer spreads through the blood, so there is little need to remove any lymph nodes that don't appear to be involved with cancer. The parathyroid glands are located in the base of the thyroid gland and should be found and preserved as much as possible, regardless of the underlying disease the patient presents with. It's important to know where these glands are located so they aren't inadvertently removed. This means keeping the inferior thyroid artery intact, as it supplies blood to 80% of the thyroid glands. Branches of this artery go off to supply the parathyroid glands so that if the artery needs to be ligated, it should be done after the branches have already been preserved. The only reason to remove the parathyroid glands is if they are grossly invaded by cancerous tissue or become ischemic at the time of surgery because their blood supply was compromised. In some cases, the parathyroid gland can be re-transplanted into a well-vascularized muscle, like the sternocleidomastoid muscle or a strap muscle. If a parathyroid gland is found to be enlarged, it should be removed. A parathyroid hormone level should be drawn in the operating room to see if the patient happens to have hyperparathyroidism before the enlarged gland or glands are to be removed. If all four parathyroid glands happen to be enlarged and the patient has a normal calcium level and normal kidney function, vitamin D deficiency should be suspected. In such cases, none of the parathyroid glands should be resected. If the blood supply is compromised to any parathyroid gland, attempts at auto-transplanting the gland to a well-vascularized muscle. This can save the gland and can prevent hypoparathyroidism. Transplanting the parathyroid gland shouldn't be done if it is involved in cancer. A frozen section of the gland can be done in the operating room to see if there is cancer in the gland. An alternative is to do a fine needle aspiration and to identify cancerous cells by frozen techniques so that the patient can have any parathyroid gland removed that is involved with cancer. Throughout the surgery, the functioning of the recurrent laryngeal nerve should be monitored by assessing the function of the vocal cords. The nerve should be isolated and protected throughout surgery. The nerve can be stimulated during surgery or the vocal cords can be assessed during surgery. Continuous nerve stimulation of important nerves can be done in surgery but might precipitate parasympathetic tone increases that may lead to cardiac arrest. Alternatively, an electrode can be built into the endotracheal tube that evaluates the function of the cords in the operating room in a way that is safer than stimulating the nerves themselves. Because vocal cord responsiveness is measured by electromyogram, only a short-acting muscle relaxant like succinylcholine should be used by the anesthetist and it should only be used during induction of anesthesia. Frozen section and fine needle aspiration should be used during surgery to identify the type of cancer involved and exactly where it is located. Papillary thyroid cancer is easily diagnosed by fine needle aspiration and frozen section analysis in surgery can help identify other cancers. Fine needle aspiration can also tell the difference between follicular cancer and a follicular adenoma. If this is indeterminate, a frozen section is obtained. Frozen section is accurate about 87% of the time. In follicular cancer, frozen section was only successful in identifying the cancer by frozen section 62% of the time. Frozen section may be necessary, too, to identify parathyroid gland tissue before autotransplantation of the gland. Minimally invasive thyroid tissue. There are several minimally invasive thyroid surgeries that are available to do total thyroidectomies. The first is endoscopic thyroidectomy in which an endoscope is used to do video-assisted thyroidectomy. One approach uses a couple of retractors and dissecting instruments placed through a small incision just two centimeters above the sternal notch. A harmonic scalpel is used to achieve hemostasis. The outcome of this type of surgery when used to treat low to intermediate risk papillary thyroid cancer is the same as if an open surgery was done. The incision is smaller and lymph nodes can be accessed. Robotic surgery is also done on thyroidectomy procedures. This surgery allows for better maneuverability of the endoscope and other microequipment with decreased fatigue from the surgeon if the surgery is extended. The downside of robotic surgery is that it takes much longer to do than open or even endoscopic surgery, and many surgeons are not knowledgeable enough to perform this kind of surgery. This is still considered an experimental surgery and the outcome of this type of surgery is still unknown. Patients will need lifetime thyroid replacement after undergoing a total thyroidectomy for thyroid cancer. Some patients are considered cured of their cancer by surgery alone, while others have a radioiodine ablation procedure after their thyroid surgery. If this procedure is done, it is usually done two to three weeks after surgery and the patient doesn't have any thyroid replacement during that time. This increases the TSH level so that the radioiodine ablation procedure works better. If the patient isn't to have a radioiodine ablation procedure, they are placed on short-acting lyosirenine or T3, which is manipulated by the surgeon or endocrinologist to keep the TSH level within normal limits and to make sure the patient's hypothyroidism symptoms are kept to a minimum. Most patients get 10 to 25 micrograms of T3 twice per day. If radioiodine surgery is planned at a later date, the T3 is withdrawn to make the procedure more effective. Some patients with low-risk differentiated thyroid carcinoma can get levothyroxine right after surgery and will receive human thyrotropin before the radioactive iodine procedure to make the procedure work better. Most patients receive calcium as a supplement after having thyroid surgery. Calcium carbonate is usually given several times per day to keep the calcium levels in the normal range. Patients who take a proton pump inhibitor or who had a gastric bypass procedure need calcium citrate because they don't have much stomach acid to process calcium carbonate. Intravenous calcium may be necessary for patients who still have low calcium levels even after getting oral calcium supplementation. If the calcium level remains low after this, the magnesium level should be drawn as it might be low, contributing to the loss of calcium. These patients will need constant surveillance of their calcium levels. If the parathyroid hormone levels are very low, it means that the parathyroid glands were lost as part of the thyroidectomy procedure. They will need calcitriol, which is 1,25-dihydroxyvitamin D, to allow for adequate absorption of intestinal calcium. Calcitriol is started right after surgery and is tapered down if the parathyroid glands have just been shocked and are gradually returning to normal function. Follow-up of a total thyroidectomy involves evaluating the patient for any changes in their voice, symptoms of low calcium levels, and their overall energy level. Thyroid hormones, calcium, and vitamin D levels need to be followed and adjusted. The pathology results are reviewed and plans are made for cancer surveillance in high-risk patients in conjunction with an endocrinologist and an oncologist. The major complications of thyroid surgery include a hematoma or seroma, hypocalcemia, voice changes, Horner syndrome, Kyle fistula, tracheal injury, esophageal injury, or dysphagia. The most common postoperative complication is hypoparathyroidism, followed by injury to the superior laryngeal nerve. The complication rate is lower in places that do this type of surgery all the time. Hematomas are extremely rare at about 1%, but carries a risk of death due to excessive bleeding and compromise of the airway. Patients with hypoparathyroidism will typically show up as having low calcium levels. Hoarseness is also common due to vocal cord swelling after an endotracheal intubation, but it is rarely caused by injury to the recurrent laryngeal nerve. Fat or collagen injections can be used if one of the vocal cords becomes paralyzed. Bilateral vocal cord paralysis is extremely rare at 0.4%, but can be extremely devastating. The patient becomes short of breath and will have stridor after being extubated and will need to be intubated again or may need a tracheostomy if the vocal cords have collapsed together. It takes a team of specialists to handle this type of injury, and attempts are usually made to repair the recurrent laryngeal nerve on at least one side of the body so the patient can talk and manage their airway. Swallowing problems can happen after a total thyroidectomy and is usually related to scar tissue in the throat and inflammation of the cartilage and pharyngeal tissues. Most patients recover their swallowing ability fully by 6 months after surgery. Up to 75% of patients will have swallowing problems a week after surgery, but this drops to less than 10% 6 months later. Some patients have disruption of the sympathetic nerves to the face, resulting in Horner syndrome. In this syndrome, the patient has meiosis, anhidrosis, and ptosis. Fortunately, it is rare at less than 0.2% after a thyroidectomy and usually happens when the lateral neck nodes need dissecting. The nerves can be stretched, resulting in damage to the nerves, or they can be temporarily ischemic, leading to a temporary manifestation of Horner syndrome. Other complications include tracheal necrosis, which stems from using too much cautery in surgery. This can cause an air leak with emphysema in the subcutaneous tissues that can be life-threatening. Similarly, esophageal injury can be a complication. Patients with air in the subcutaneous tissues might have either tracheal or esophageal perforation. Surgical Adrenalectomy The treatment of choice for patients with Cushing's syndrome, which involves a corticotropin or ACTH-secreting pituitary tumor, is resection of the pituitary tumor using a transphenoidal approach. For patients who still have problems, mitotain can be given to medically eradicate the function of the adrenal glands, or surgery is done to definitively resolve the patient's Cushing's syndrome symptoms. Most of the time, Cushing's syndrome stems from an ACTH-secreting tumor in the pituitary gland. These are fortunately benign tumors that are extremely small and located in the pituitary gland. The actual treatment of choice is a transphenoidal microadenomectomy, which is usually done by a neurosurgeon. The cure rate for this approach is about 80-90% if the tumor is small, but only 60% if the tumor is large. The cure rate is only about 50% because patients develop recurrence of their symptoms. If symptoms are present after transphenoidal surgery, there are a couple of good options for these patients. They can have another transphenoidal surgery to further destroy any remaining tumor, but this results in other pituitary gland deficiencies. The pituitary gland can also be eradicated, or may receive adrenal enzyme inhibitors to block adrenal function. A typical adrenolytic agent used is mitotain, which can be used before or after surgery to the pituitary gland. Finally, surgical removal of the adrenal gland can help cure the patient. Women who want to remain fertile might opt for a surgical adrenalectomy because it avoids the potential loss of female hormones if too much of the pituitary gland is lost in surgery or radiation to the pituitary gland. Even giving mitotain is not ideal for women desiring fertility because it is teratogenic and can't be used in pregnancy. The definitive treatment is a bilateral adrenalectomy when rapid management of excessive cortisol levels are necessary, or when other therapies haven't worked. It has been used on pregnant women with preservation of the pregnancy, which wouldn't happen if other treatments were used. During this time, having a surgical adrenalectomy is a safe procedure because most surgeries are done using a laparoscopic approach. This is much less invasive than an open adrenalectomy. Patients can be monitored for Nelson syndrome, which is corticotropin tumor progression after transphenoidal pituitary surgery. The downside of removing the adrenal glands is that the patient will need cortisol and mineralocorticoid replacement for the rest of their life. On the other hand, trying to remove just one adrenal gland never works for Cushing's syndrome unless the patient also has irradiation to the pituitary gland. This approach is rarely recommended. A laparoscopic bilateral adrenalectomy can be done by means of an anterior or posterior approach with shorter stays in the hospital of less than five days and fewer complications. The glands must be removed in toto with the capsule of the adrenal glands left intact at the time of surgery. If the capsule is disrupted, cells can leak out and implant in the abdomen, causing recurrent Cushing's syndrome. When this happens, surgery just can't be done to treat this multifocal disease process. After a total bilateral adrenalectomy, most surgeons give glucocorticoids in the form of hydrocortisone in the operating room every eight hours. It is tapered over the next two days until the patient can receive oral fludrocortisone and oral hydrocortisone. Other cortisone replacement medications that can be used include dexamethasone, prednisone, or cortisone acetate. When the adrenal glands are removed, the patient's pituitary tumor can get larger, resulting in Nelson syndrome. But the responsiveness of the adrenal glands is no longer a problem. Cerebral levels should be done before giving hydrocortisone to make sure that no residual adrenal tissue remains, and MRI and serum ACTH levels can be done yearly to make sure Nelson syndrome is not present. This should be done for seven years after surgery. The main outcome is that the patient's quality of life is improved, although half of patients are still tired. Nelson syndrome can occur as an enlargement of the pituitary tumor that can be seen on an MRI evaluation. This occurs within three years of having pituitary gland surgery and an adrenalectomy. Patients with high ACTH levels will have a greater risk of developing Nelson syndrome than patients with low ACTH levels. High ACTH levels from Nelson syndrome will lead to increased skin pigmentation, headaches, cranial nerve abnormalities, and visual field deficits. Nelson syndrome is the most common complication of an adrenalectomy without prior irradiation of the pituitary gland occurring in half the patients. Younger patients get this more than older patients. The best way to predict Nelson syndrome is to do regular plasma ACTH levels, which will be elevated in Nelson syndrome. An MRI can further identify this problem. The basic cause of the problem is negative feedback of the glucocorticoids given to the patient after the adrenalectomy. If not enough hydrocortisone is given, the pituitary adenoma will enlarge, leading to Nelson syndrome. The best way to prevent it is to irradiate the pituitary gland before doing the adrenal surgery, especially if the pituitary adenoma is large enough to be seen on an MRI evaluation. Nelson syndrome is quite hard to cure because it invades the pituitary gland and can turn into a cancerous tumor. When the tumor is big enough to cause symptoms, the best outcome is given by doing a transphenoidal surgery to remove the enlarged tumor. The surgery is risky, with 70% of patients developing a loss of all pituitary function. Therefore, it is recommended to irradiate the pituitary gland if there is any evidence of ongoing tumor in the pituitary gland after the adrenalectomy. There is really no good medical treatment for Nelson syndrome. Rarely, ciproheptadine or valproic acid can be used, which might lower ACTH levels. Chromocryptine works in 50% of cases, and cabergoline is used experimentally but effectively in some patients. Naloxone and indomethacin don't work, but rosiglitazone and octreotide have been found to be temporarily effective. Tamazolamide is sometimes used to treat pituitary tumors that have become cancerous after an adrenalectomy. Key Takeaways A total thyroidectomy is the treatment of choice for many benign and cancerous lesions of the thyroid gland. The surgery is much safer and more cosmetically appealing when done robotically or with an endoscope. There are several complications to thyroid surgery involving a loss of parathyroid hormone function, dysphagia, esophageal perforation, tracheal perforation, and hoarseness. Most Cushing disease is caused by an ACTH-secreting microadenoma of the pituitary gland. A total adrenalectomy is done if transphenoidal removal of the microadenoma fails to control the Cushing syndrome symptoms. The major complication of removing the adrenal glands is Nelson syndrome involving enlargement of the pituitary adenoma. Quiz Number 1 Which thyroid problem would not be treated with a total thyroidectomy? a. Papillary carcinoma of the thyroid b. A single 10 mm thyroid nodule c. Medullary carcinoma of the thyroid d. Graves disease Answer b. A single nodule of that size in the thyroid gland will not require a total thyroidectomy but can be removed as a nodulectomy. Number 2 What is the most common complication of having a total thyroidectomy? a. Esophageal perforation b. Bilateral vocal cord paralysis c. Tracheal ischemia d. Hypoparathyroidism Answer d. The most common complication of a total thyroidectomy is hypoparathyroidism, which can stem from inadvertent removal of these glands or temporary shock to the glands after surgery. Number 3 The patient has developed hypoparathyroidism after having a total thyroidectomy. What is the simplest lab abnormality that will be found when this occurs? a. Hypocalcemia b. Hypercalcemia c. Low vitamin D levels d. Hypophostedemia Answer a. The main finding in postoperative hypoparathyroidism is hypocalcemia, which is an easy lab to draw and follow over time. Number 4 In what form is calcium replaced in patients who have developed hypoparathyroidism after a total thyroidectomy? a. Calcium citrate b. Calcium carbonate c. Calcium chloride d. Calcium gluconate Answer b. The main treatment for most patients with hypoparathyroidism and low calcium levels is to give calcium carbonate, unless the patient takes a proton pump inhibitor or had a gastric bypass surgery. Number 5 Which nerve injury results in paralysis of the vocal cords in a total thyroidectomy? a. Recurrent laryngeal nerve b. Superior laryngeal nerve c. Lateral laryngeal nerve d. Twelfth cranial nerve Answer a. Injury to the recurrent laryngeal nerve is most likely to result in paralysis of one of the vocal cords as a complication of a total thyroidectomy. Number 6 A patient has developed subcutaneous air in the anterior chest after a total thyroidectomy. What surgical injury is suspected? a. Collapsed lung b. Tension pneumothorax c. Tracheal perforation d. Esophageal ischemia Answer c. A tracheal perforation can happen after a total thyroidectomy. The main finding with this complication is subcutaneous emphysema in the anterior chest wall. Number 7 Which complication of a total thyroidectomy is likely to be the most life-threatening? a. Bilateral vocal cord paralysis b. Horner syndrome c. Esophageal perforation d. Neck hematoma Answer d. A neck hematoma is fortunately a rare complication of a total thyroidectomy, but is a potentially life-threatening complication when it occurs as it can encroach on the airway. Number 8 What is the main etiology behind Cushing syndrome? a. Macroadenoma of the adrenal gland b. Macroadenoma of the pituitary gland c. Carcinoma of the pituitary gland d. Microadenoma of the pituitary gland Answer d. The most common finding in patients with Cushing syndrome is a microadenoma of the pituitary gland that can't be seen on imaging studies. Number 9 Which patient is most likely to have Nelson syndrome after a total bilateral adrenalectomy? a. A patient with low ACTH levels after the adrenalectomy b. A patient who had irritation to the pituitary gland prior to adrenalectomy c. A patient who had bilateral adrenalectomy but didn't have pituitary irradiation d. A patient who had transphenoidal pituitary surgery before having a bilateral adrenalectomy Answer c. A patient who had a bilateral adrenalectomy but didn't have pituitary irradiation can easily get Nelson syndrome after surgical intervention. Number 10 Patients are monitored for Nelson syndrome after having a bilateral adrenalectomy with an MRI evaluation of the pituitary gland. For how long should this monitoring take place? a. One year after surgery b. Three years after surgery c. Five years after surgery d. Seven years after surgery Answer d. While patients need lifelong follow-up, they only need annual MRI evaluations of the pituitary gland for Nelson syndrome for seven years.