Skull Base and Pituitary Surgery Flashcards
A 45-year-old man presents with sudden onsent headache, nausea, vomiting and visual disturbance. On examination he is apyrexial, hypotensive, and tachycardic but does not have neck stiffness or photophobia. Visual fields appear to be constricted on confrontation. CT head is abnormal therefore MRI is done. Which one of the following is appropriate acute management?
a. Dexamethasone
b. Formal visual field tests
c. Pituitary profile and start empirical intravenous
hydrocortisone
d. Lumbar puncture
e. Transsphenoidal surgery
c. Pituitary profile and start empirical intravenous
hydrocortisone
Pituitary apoplexy is characterized by sudden onset headache, nausea, vomiting, with or without acute visual disturbance and cranial nerve palsy (2nd, 3rd, 4th, 6th) due to pituitary hemorrhage and/ or infarction. Precipitating factors in those with or without an underlying pituitary tumor include hypertension, major surgery, dynamic testing of pituitary function, anticoagulation/coagulopathy, estrogen therapy, dopamine receptor agonist initiation/withdrawal, radiotherapy, pregnancy and head trauma. Assessment should focus on history and examination findings consistent with pre- existing pituitary dysfunction. Anterior pituitary function tests (FT4, TSH, IGF-1, random cortisol, prolactin, growth hormone, FSH/LH, and testosterone in men or estradiol in women) should be checked urgently but those with hemodynamic instability (i.e. Addisonian crisis) should be started on empirical hydrocortisone. Indications for empirical steroid therapy in patients with pituitary apoplexy are hemodynamic instability, altered consciousness level, reduced visual acuity and severe visual field defects. Patients who do not fulfill the criteria for urgent empirical steroid therapy should be considered for treatment with steroids, if their 09 00 serum cortisol is less than 550 nmol/L; The majority of the patients (nearly 80%) will have deficiency of one or more anterior pituitary hormones at presentation. As most of the patients have underlying macroadenomas, partial hypopituitarism would be expected to have been present in the majority even before the apoplectic episode. Clinically, the most crucial deficit is that of adrenocorticotroph hormone (ACTH) in up to 70% of the patients. Thyrotrophin and gonadotrophin deficiencies are observed in 50% and 75% of the patients, respectively. Hyponatremia has been reported in up to 40% of the patients because of either the syndrome of inappropriate antidiuretic hormone secretion or hypocortisolism. Patients with pituitary apoplexy who have low serum prolactin (PRL) levels at presentation have the highest intrasellar pressure and are the least likely to recover from hypopituitarism after decompressive surgery. Formal visual fields assessment, using Humphrey visual field analyzer or Goldmann perimeter must be undertaken when the patient is clinically stable, preferably within 24 h of the suspected diagnosis. MRI of the pituitary is required to confirm the diagnosis. Hemorrhage appears hyperintense on non-enhanced T1W images and, in the acute stage, hyperdense on CT and may rarely contain a fluid level (as in this case) with evidence of optic chiasm being stretched across the top of the mass. Patients with pituitary apoplexy who are without any neuro-ophthalmic signs or mild and stable signs can be considered for conservative management with careful moni- toring. In patients with reduced visual acuity or defective visual fields, formal assessment of visual fields and acuity should be performed every day until a clear trend of improvement is observed. Indications for urgent neurosurgical decompression include deteriorating level of consciousness, severely reduced visual acuity, severe/persistent/worsening visual field defect. Ocular paresis because of involvement of III, IV or VI cranial nerves in cavernous sinus in the absence of visual field defects or reduced visual acuity is not in itself an indication for immediate surgery. Resolution will typically occur within days or weeks with conservative management. Surgery should be performed preferably within the first 7 days of onset of symptoms by an experienced pituitary surgeon.
FURTHER READING Rajasekaran S, Vanderpump M, Baldeweg S, Drake W, Reddy N, Lanyon M, Markey A, Plant G, Powell M, Sinha S, Wass J. UK guidelines for the management of pituitary apoplexy. Clin Endocrinol (Oxf) 2011;74(1):9-20.
A 64-year-old male presented with severe headache and visual disturbance. Plain CT imaging revealed a sellar mass but no other acute abnormality. Contrast imaging was performed (below). Which one of the following is the most important next management step?
a. Pituitary profile
b. Formal visual field assessment
c. Image guided biopsy
d. Lumbar puncture
e. ICP monitoring
d. Lumbar puncture
Imaging above is a CT angiogram demonstrating a giant ICA aneurysm expanding the sella. The most important next step is to clarify the likelihood that it has ruptured, and if so the patient will need to be started on subarachnoid hemorrhage treatment and the aneurysm secured. Options include lumbar puncture (though many would avoid this given the risk of aneurysm rupture) or assessing hemosiderin on MRI. Others may argue that given the history and the size of the aneurysm, treatment should be performed expediently as in aneurysmal subarachnoid hemorrhage patients.
A 57-year-old undergoes elective transsphenoidal surgery for a non-functioning macroadenoma compressing the optic chiasm. Recovery was uneventful and routine bloods on postoperative day 1 were normal, and endocrine profile showed FT4 12 pmol/L (11.5-22), TSH 0.9 mU/L (0.35-5.5) and 9 am cortisol 154 nmol/L. Which one of the following statements regarding further management is LEAST accurate?
a. If thyroid function tests are normal on day 3 or 4 a further assessment should take place at 4-8 weeks
b.Evening steroid dose should not be omitted
if checking 9 am cortisol
c. If day 2 postoperative 9 am cortisol >550 nmol/L does not require steroid replacement
d. If day 2 postoperative 9 am cortisol 400550 nmol/L requires hydrocortisone only during severe illness
e. If day 2 postoperative 9 am cortisol <400 nmol/L does requires regular oral hydrocortisone
b.Evening steroid dose should not be omitted
if checking 9 am cortisol
If preoperative steroid reserve adequate or unknown:
* Check 9 am serum cortisol on day 2 and on day 3 after surgery, in patients with no evidence of cortisol deficiency before operation. If already on hydrocortisone replacement, omit the evening dose for the previous day before checking.
In patients without Cushing’s disease (9 am cortisol: >550 nmol/L no requirement for hydrocortisone, 400-550 nmol/L hydrocortisone only during severe illness or stress, <400 nmol/L start regular oral hydrocortisone). If preoperative steroid reserve deficient:
* In patients with proven cortisol deficiency before surgery, continue hydrocortisone and consider changing over to maintenance dosage when stable. These patients will need further assessment at 4-8 weeks with anterior hormone profile and short synacthen test to determine whether they will need long-term steroids;
* FT4 and TSH should be assessed on day 3 or day 4 and thyroid hormone replacement should be considered if deficient.
* If FT4 and TSH normal further assessment should take place at 4-8 weeks.
FURTHER READING Rajasekaran S, Vanderpump M, Baldeweg S, Drake W, Reddy N, Lanyon M, Markey A, Plant G, Powell M, Sinha S, Wass J. UK guidelines for the management of pituitary apoplexy. Clin Endocrinol (Oxf) 2011;74(1):9-20.
A 65-year-old man undergoes transsphenoidal surgery for a non-functioning macroadenoma. Postoperatively on day 1 the nurses notice he is passing large volumes of dilute urine via his catheter. Which one of the following criteria is LEAST suggestive of diabetes insipidus?
a. Urine specific gravity <1.003 or osmolality <200 mOsmol/kg
b. Urine output >250 ml/h for 2 consecutive hours
c. Serum sodium normal or raised
d. Primary adrenal insufficiency
e. Inability to concentrate urine to >300 mOsmol/L in the presence of clinical dehydration
d. Primary adrenal insufficiency
Diabetes insipidus cannot occur in primary adrenal insufficiency (hypocortisolism/hypoaldosteronism) because mineralocorticoid activity is required for kidneys to produce free water.
A 17-year-old female presents with an 8 month history of secondary amenorrhea. More recently she has noticed that she is more thirsty and is passing large volumes of urine. Her examination is otherwise unremarkable. Routine blood tests are normal and endocrine profile shows: FSH 5.5 U/L (follicular 0.5-5, mid-cycle 8-33, luteal 2-8), LH 2.8 U/L (follicular 3-12, mid-cycle 20-80, luteal 3-16), estradiol 32 pmol/L (follicular 17-260, luteal 180-1100), prolactin 990 mU/L (60-620), 9 am cortisol 400 nmol/L, fasting blood glucose 5.5 mmol/L, serum calcium 2.35 mmol/ L (2.2-2.6). Water deprivation test: serum osmolality 300 mOsmol/kg, urine 200 mOsmol/kg at 6 h, post-DDAVP urine osmolality 800 mOsmol/kg. MRI head is shown. Which one of the following would you perform next?
a. Serum and CSF HCG and AFP
b. Ultrasound pelvis/ovaries
c. Insulin tolerance test
d. Short synacthen test
e. Visual field tests
a. Serum and CSF HCG and AFP
Water deprivation test involves serial 2 hourly measurement of serum and urine osmolality (and body weight) over a water deprivation period of 6-8 h—if serum osmolality>290 and urine<300by the end it is suggestive of DI and DDAVP is given. If kidneys are functioning normally, DDAVP should cause a rise in urine osmolality to>750 suggesting a cranial (failure of posterior pituitary vasopressin secretion, as in this case) cause for the DI. This case describes an adolescent presenting with a hypopituitarism including cranial diabetes insipidus, with an homogeneously enhancing suprasellar mass and smaller enhancing pineal cyst. The main concern is of a germinoma (synchronous suprasellar and pineal) given her age and imaging, rather than lymphocytic hypophysitis which presents later although the two may be difficult to distinguish. MRI of the whole spine with contrast should also be performed given these findings. In a small proportion of germinomas, there may be non-germinomatous elements secreting BHCG or AFP hence serum and CSF should be checked urgently. If these are both negative biopsy should be performed to confirm a diagnosis of germinoma and start radiotherapy with or without chemotherapy.
A 33-year-old female who presents with a several week history of headache, extreme fatigue and malaise. She gave birth to her first child 2 months ago via vaginal delivery. Examination was unremarkable. Routine bloods were normal, and endocrine profile showed: Prolactin 801 mU/L (100-550), FT4 10 pmol/L (11.5-22), TSH 0.1 mU/L (0.35-5.5). Short synacthen test: 0 h cortisol 55 nmol/L, 30 min cortisol 155 nmol/L. MRI is shown. Which one of the following is most likely?
a. Lymphocytic hypophysitis
b. Sheehan’s syndrome
c. Non-functioning adenoma
d. Langerhans cell histiocytosis
e. Sarcoidosis
a. Lymphocytic hypophysitis
The clinical picture is that of anterior pituitary pathology with early involvement/impairment of corticotrophs (short synacthen test suggesting adrenal insufficiency; normally increase should be >200 nmol/L and 30 min value >600 nmol/L) and thyrotrophs (low TSH). This is in contrast to non-functioning pituitary adenomas where there is usually early involvement of gonadotrophs. Lymphocytic hypophysitis is most commonly seen during pregnancy or postpartum period and represents an inflammatory/autoimmune process affecting the pituitary gland and the pituitary stalk (infundibulum). Presentation is with pituitary failure such as lethargy, amenorrhea, diabetes insipidus and visual disturbance (if there is optic chiasm compression). MRI may show a homogeneously enhancing sellar/infundibular mass and T1WI may even show loss of posterior pituitary bright spot (normally present due to vasopressin storage) in cranial diabetes insipidus. Where there is a high clinical suspicion (e.g. postpartum, other autoimmune conditions, ipilimumab use, absence of serum markers for sarcoidosis) treatment with steroids and supportive therapy can be initiated. However, if the picture is uncertain or no response to steroids biopsy should be performed as it is the only way to make the diagnosis.
A 48-year-old male presents with low mood, malaise and reduced exercise tolerance. He has a past history of IHD and a non-functioning pituitary adenoma resected 5 years ago resulting in partial anterior hypopituitarism. He is normally on thyroxine and hydrocortisone replacement therapy. On examination his BMI is 39 kg/m 2 and shows central adiposity. His endocrine tests show 9 am cortisol 410 nmol/L, IGF-1 8 nmol/L (16-118), FT4 16 pmol/L (11.5-22) and TSH 0.03 mU/L (0.35-5.5). Which one of the following is most appropriate to confirm the diagnosis?
a. Growth hormone levels
b. GHRH-arginine stimulation test
c. IGF-binding protein 3 measurement
d. Insulin tolerance test
e. Water deprivation test
b. GHRH-arginine stimulation test
The clinical features of growth hormone deficiency are nonspecific and include lethargy, low mood, poor quality of life, loss of muscle mass and central adiposity. GH is normally secreted in a pulsatile fashion (5 per 24 h) hence random measurement of levels is not helpful. A low IGF- 1 level may be present in 60-70% of patients with GH deficiency, and may suggest the need for dynamic tests of GH secretion. Equally, a low IGF-1 in the presence of 3 or more other anterior pituitary hormone deficiencies in an otherwise healthy individual is a strong predictor of GH deficiency and treatment should be considered without dynamic testing. Contraindications to GH therapy is active malignancy (other than pituitary). If dynamic testing is required, the gold standard is insulin tolerance test (ITT) where insulin administration should provoke a rise in GH (peak level <10 mU/L or <3 μg/L is suggestive of severe GH deficiency). However, ITT is contraindicated in those with IHD and epilepsy due to the risks associated with hypoglycemia and may give a false result in obese patients. In this situation, other dynamic tests include GNRH-arginine stimulation and glucagon stimulation test which have a higher sensitivity than IGFBP-3 levels.
A 56-year-old presents with a 2-month history of headache and visual disturbance. Confrontation testing revealed a bitemporal hemianopia. Routine bloods were normal and endocrine profile is: FT4 pmol/L 8.5 (11.5-22), TSH 0.5 mU/L (0.35-5.5), FSH 1.0 U/L (1.4-18.1), LH 2.5 U/L (3-8), prolactin 900 mU/L (45-375), testosterone 3.5 nmol/L (8.4-28.7), 9 am cortisol 405 nmol/L. MRI is shown. Which one of the following is most likely?
a. Non-functioning adenoma
b. Thyrotropinoma
c. GH-secreting pituitary adenoma
d. Prolactinoma
e. Cushing’s disease
a. Non-functioning adenoma
Pituitary adenomas are the most common neoplasms in the sellar region and comprise 10-15% of all primary brain tumors. They are classified as microadenomas (<10 mm) and macroadenomas (>10 mm). Furthermore, they may be non-functional pituitary adenomas (clinically not hormonally active) or functional (clinically showing signs of hormone excess). Non-functional adenomas account for 15-30% of pituitary adenomas and show gonadotroph (FSH, LH) deficiency in 80%, followed by somatotrophy (GH secretion) deficiency, and later thyrotrophs (TSH) and corticotrophs (ACTH) deficiency in 20-50%. Gonadotrophs are the commonest primary cell type involved in NFPA. As such, patients tend to present with hypogonadotrophic hypogonadism early, and features of GH deficiency, secondary hypothyroidism and secondary adrenal insufficiency later on. Hypogonadotrophic hypogonadism is characterized by Large NFSs compress the pituitary stalk, causing impairment of dopamine transport to the lactotrophs and a slight rise in prolactin secretions above normal (but prolactinoma is usually associated with levels >200 mU/L). Macroadenomas of either type (functional or non-functional) may present with mass effect on adjacent structures (e.g. chiasmal compression) or pituitary apoplexy. MRI with and without contrast is the imaging modality of choice. Management of nonfunctioning pituitary adenoma is with elective transsphenoidal surgery if there is evidence of optic chiasm compression (as in this case with suprasellar extension)—otherwise endocrine, ophthalmologic and imaging surveillance is appropriate.
A 50-year-old male presents with a 12 month history of reduced libido and lethargy. On examination there were mild left sided 3rd and 6th nerve palsies. Routine bloods were normal and endocrine profile showed: FT4 8 pmol/L (11.5-22), TSH 0.4 mU/L (0.355.5), FSH 2.2 U/L (1.4-18.1), LH 3.5 U/L (3-8), testosterone 6.8 nmol/L (8.4-28.7), IGF-1 35 nmol/L (16-118), prolactin 880 mU/L (45-375). MRI is shown. Which one of the following is most appropriate next?
a. Stereotactic radiosurgery
b. Transsphenoidal debulking followed by stereotactic radiosurgery
c. Cabergoline
d. Somatostatin
e. Petrous sinus sampling
b. Transsphenoidal debulking followed by stereotactic radiosurgery
There is extensive cavernous sinus involvement hence transsphenoidal surgery alone is unlikely to be sufficient (but will decompress/separate tumour mass from optic nerve), and given the features of a non-functional pituitary adenoma stereotactic radiosurgery is the appropriate next action as medical therapy is unlikely to be of benefit.
Which one of the following statements regarding diagnosis and management of prolactinomas is LEAST accurate?
a. Prolactinomas are managed medically with dopamine receptor agonists
b. Hook effect describes spuriously high prolactin levels due to macroprolactin complexes
c. Compression of the pituitary stalk can cause a mildly raised prolactin
d. Prolactin levels in a prolactinoma are usually >2000 mU/L
e. Hypothyroidism may result in hyperprolactinemia
b. Hook effect describes spuriously high prolactin levels due to macroprolactin complexes
Prolactinomas are the most common secreting pituitary adenomas and tend to arise laterally within the anterior lobe of the pituitary gland. They may depress the floor of the sella turcica or expand one side of the gland, causing a subtle upwardly convex bulge and contralateral displacement of the infundibulum. Hyperprolactinemia in men interferes with sperm production (infertility) and testosterone production (lethargy, reduced libido, reduced muscle mass), galactorrhea, loss of pubic/axillary hair, and erectile dysfunction (and small gonads in pre- pubertal boys). In females, hypeprolactinemia reduces estradiol production and this causes irregular menstrual cycles, amenorrhea, galactorrhea and premature menopausal symptoms (does not cause similar symptoms in postmeno- pausal women). Blood tests show prolactin levels >2000 mU/L (note that hypothyroidism may also cause hyperprolactinemia). Macroprolactin with its longer half-life and biological inert nature needs to be measured, and may cause a spuriously high prolactin level. Equally, depending on the assay used, if prolactin levels are truly very high they may saturate the assay giving a near-normal result (Hook effect). Estrogen containing oral contraceptives can stimulate lactotrophs and cause hyperprolactinemia. The primary treatment of prolactin-secreting microadenomas is medical and the role of imaging in cases of hyperprolactinemia is to assess size and any chiasmal compression. Bromocriptine and cabergoline are both safe options for females in the reproductive age group presenting with a microprolactinoma if they are planning a preg- nancy in the near future, and have not been associated with fetal malformation. The therapy can be stopped once pregnancy is confirmed. Dopamine agonists reduce prolactin levels and induce ovulation, hence females started on them are possibly at higher risk of pregnancy and should be given advice regarding contraception at initiation if they do not wish to become pregnant. Management of prolactinomas during pregnancy is challenging as prolactin measurements are unreliable. There is <5% chance of microprolactinoma regrowth and 15-40% chance of macroprolactinoma regrowth during pregnancy. As such, patients need to be kept under close surveillance with periodic formal visual field assessments. Imaging in other secreting pituitary adenomas (TSH, GH, ACTH) is also important to localize the exact position of the tumor for surgical treatment. In particular, given the high morbidity of Cushing’s disease if no lesion is found on MRI then inferior petrosal and/or cavernous sinus venous sampling may be necessary to grossly lateralize an adenoma for surgery.
Which one of the following statements regarding management of incidentally found pituitary adenomas (except prolactinomas) is most accurate?
a. Anterior pituitary hormone profile should only be performed if the patient is symptomatic
b. MRI surveillance for lesions <10 mm and >10 mm is the same
c. Indications for surgery include secreting tumours
d. Macroincidentalomas should be reimaged at 12 months
e. Formal visual field testing should be performed as a baseline
c. Indications for surgery include secreting tumours
Due to improvements in imaging there has been a rise in the number of incidental pituitary adenomas discovered on cranial imaging with rates of 530% for those <10 mm (microincidentaloma) and 0.1-0.25% for those >10 mm in size (macroincidentaloma). They should be investigated for subclinical disease even if asymptomatic including endocrinological history and examination, anterior pituitary profile, MRI pituitary (if lesion found on CT) and, if clinical visual field defect or evidence of chiasmal compression on imaging, formal visual field testing. If all results are normal, microincidentalomas should be rescanned at 1 year then every 1-2 years for the first 3 years then less frequently after that. Macroincidentalomas should be rescanned at 6 months then at least yearly for the first 3 years. Repeat anterior pituitary hormone profile should only be performed if symptomatic or MRI changes are seen. Indications for surgery include visual field deficit, optic nerve/chiasm compression, ophthalmoplegia, pituitary apoplexy with severely reduced visual acuity or field defect, and evidence of secreting tumor (e.g. Acromegaly, Cushing’s disease). FURTHER READING Freda PU, Beckers AM, Katznelson L. Pituitary incidentaloma: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 2011;96(4):894-904.
Which one of the following statements regarding medical management of secreting pituitary adenomas is LEAST accurate?
a. Octreotide used in patients with acromegaly
b. Cabergoline is a dopamine receptor antagonist
c. Bromocriptine is used in the treatment of prolactinoma
d. Pegvisomant is a GH receptor blocker and useful if somatostatin fails in acromegaly
e. Mitotane used for Cushing’s disease
b. Cabergoline is a dopamine receptor antagonist
Dopamine receptor agonists (e.g. bromocriptine, cabergoline) augment physiological inhibition of prolactin secretion. Octreotide is a somatostain analog used in the treatment of acromegaly is associated with the development of gallstones and reduced gall bladder contractility, but causes >2% tumor reduction in 75% of patients treated. GI side effects are common, and glycemic control also.
A 36-year-old patient with Cushing’s syndrome but normal ACTH levels is referred. There is no visual compromise. Pituitary MRI shows a 3 mm hypodense area in the lateral aspect of the pituitary gland. Which one of the following is the next appropriate management?
a. Laparoscopic adrenalectomy
b. Transsphenoidal surgery
c. Inferior petrosal sinus sampling
d. High-dose dexamethasone test
e. Start octreotide
c. Inferior petrosal sinus sampling
This finding is nonspecific and occurs in up to 10% of healthy people. It may or may not be related to Cushing syndrome. The odds are good that the patient has a pituitary tumor, but the MRI findings do not prove this. The MRI is diagnostic only if it shows a large tumor. One option is to proceed directly to pituitary surgery because a patient with abnormal MRI findings has a 90% chance of having an ACTH-secreting pituitary tumor. To achieve more diagnostic certainty, one has to perform bilateral simultaneous inferior petrosal sinus sampling (IPSS) for ACTH levels. Catheters are advanced through the femoral veins into the inferior petrosal sinuses, which drain the pituitary gland, and blood samples are obtained for ACTH levels. If ACTH levels in the petrosal sinuses are significantly higher than those in peripheral samples, the pituitary gland is the source of excessive ACTH. If there is no gradient between petrosal sinus and peripheral levels of ACTH, the patient probably has a carcinoid tumor somewhere. The accuracy of the test is further increased if ACTH responses to injection of exogenous CRH are measured. If sinus sampling is positive for a gradient transsphenoidal surgery (TSS) should be sched- uled with an experienced neurosurgeon who is comfortable examining the pituitary for small adenomas. ACTH levels from the right and left petrosal sinuses obtained during the sampling study may tell the neurosurgeon in which side of the pituitary gland the tumor is likely to be found, but this information is not 100% accurate. If IPSS shows no gradient in ACTH levels, start the search for a carcinoid tumor (e.g. lung, adrenal, GI) and treatment as appropriate. FURTHER READING Samuels MH. Cushing syndrome. In: McDermott MT (Ed.), Endocrine secrets. Saunders, Elsevier, 2013.
Which one of the following statements regarding Cushing’s disease is most accurate?
a. It is often due to ACTH-secreting pituitary adenoma
b. Primary management is surgical resection of the tumor
c. High-dose dexamethasone suppression test is able to lateralize the side of ACTH-secreting microadenoma within the pituitary gland
d. It may be caused by ectopic ACTH producing tumors
e. Can cause amenorrhea in females and infertility in males
e. Can cause amenorrhea in females and infertility in males
Cushing’s syndrome (hypercortisolism) can present in children and young adults with an increase in body weight, central obesity and growth retardation. In adults, it is associated with mood facies, proximal myopathy, bruising, abdominal striae, oligomenorrhea/amenorrhea in females, impotence in males, infertility, hirsutism, hypertension and diabetes. Adrenal tumors are commoner in children under 10 (neuroblastoma) causing ACTH-independent Cushing’s syndrome with signs of virilization. Cushing’s disease due to ACTH-secreting pituitary tumor is commoner in older children and adults. In adults, ectopic ACTH production due to lung cancer or carcinoid/neuroendocrine tumor can also occur. Initial screening tests such as 24 h urinary cortisol collection, 9 am and midnight cortisol (loss of diurnal variation; remains high), and overnight (low-dose) dexamethasone suppression test help confirm the diagnosis of hypercortisolism. Second line localization tests aim to differentiate hypercortisolism based on whether it is secondary to increased ACTH secretion (e.g. ACTH-secreting pituitary tumor or ectopic/carcinoid tumor) or not (e.g. adrenal tumor). Third line tests aim to differentiate location of ACTH-dependent hypercortisolism as pituitary (reduces ACTH/cortisol production in response to high-dose dexamethasone; gradient on petrosal sinus sampling) or ectopic tumor (no reduction in ACTH/cortisol secretion in response to high-dose dexamethasone; cortisol rise if CRH stimulation test; no cortisol rise on CRH stimulation; no gradient on petrosal sinus sampling).
Which one of the following would be most appropriate treatment following failure of transsphenoidal surgery to treat Cushing’s disease?
a. Surveillance imaging
b. Repeat transsphenoidal surgery
c. Cabergoline
d. Octreotide
e. Bilateral adrenalectomy
b. Repeat transsphenoidal surgery
Patients with inadequately treated Cushing’s syndrome have a markedly increased mortality rate (four- to fivefold above the normal rate), usually from cardiovascular disease or infections. Hypertension, impaired glucose tolerance, dyslipidemia, and visceral obesity all contribute to the excess risk for cardiovascular mortality. This excess mortality normalizes with adequate therapy. If TSS does not cure a patient with Cushing’s disease, alternative therapies must be tried because patients with inadequately treated hypercortisolism have increased morbidity and mortality rates. Of the various options after failed surgery, none is ideal. Patients may require repeat pituitary surgery, radiation therapy, medical therapy to block adrenal cortisol secretion (e.g. ketoconazole, metyrapone, mitotane, or etomidate), centrally acting agents that suppress ACTH secretion, and glucocorticoid receptor blocker (mifepristone). Bilateral adrenalectomy can be safely performed via a laparoscopic approach, with low morbidity in experienced hands. However, this procedure leads to lifelong adrenal insufficiency and dependence on exogenous glucocorticoids and mineralocorticoids. The other main drawback is the development of Nelson syndrome in up to 30% of patients after adrenalectomy. Nelson syndrome is the appearance, sometimes years after adrenalectomy, of an aggressive corticotroph pituitary tumor.
Endoscopic view from within sphenoid sinus.
Which one of the following labels appropriately
identifies the opticocarotid recess?
E—Opticocarotid recess.
A—planum sphenoidale, B—chiasmatic groove (CG), C—tuberculum sellae, D—optic nerve prominence, E—opticocarotid recess, F—clival recess, G—prominence of the internal carotid artery The panoramic view provided by the endoscope of the bony prominences and depressions inside the sphenoid sinus allows one to see a sort of “fetal face,” where the forehead corresponds to the planum sphenoidale, the eyes to the two opticocarotid recesses, the eyebrows to the two bony protuberances covering the optic nerves, the nose to the sellar floor, and the mouth to the clival indentation, laterally limited by the two paraclival carotid arteries, representing the cheeks.
Contains maxillary nerve (CNV2)
1—k, Foramen rotundum;
a—Lesser, greater wings of sphenoid bone, b—Carotid groove, c—Pituitary fossa, d—Foramen lacerum, e—Condylar fossa (mandibular), f—Facial hiatus, g—Temporal bone, h—Internal auditory meatus, i—Optic canal, j—Superior orbital Fissure, k—Foramen rotundum, l—Foramen ovale, m—Foramen spinosum, n—Foramen jugulare, o—Hypoglossal Canal.
Contains greater petrosal nerve (VII) which joins with deep petrosal nerve to form vidian nerve (of the pterygoid canal).
2—d, Foramen lacerum,
a—Lesser, greater wings of sphenoid bone, b—Carotid groove, c—Pituitary fossa, d—Foramen lacerum, e—Condylar fossa (mandibular), f—Facial hiatus, g—Temporal bone, h—Internal auditory meatus, i—Optic canal, j—Superior orbital Fissure, k—Foramen rotundum, l—Foramen ovale, m—Foramen spinosum, n—Foramen jugulare, o—Hypoglossal Canal.
Contains facial nerve (VII), vestibulocochlear (VIII)
2—h, Internal auditory meatus
a—Lesser, greater wings of sphenoid bone, b—Carotid groove, c—Pituitary fossa, d—Foramen lacerum, e—Condylar fossa (mandibular), f—Facial hiatus, g—Temporal bone, h—Internal auditory meatus, i—Optic canal, j—Superior orbital Fissure, k—Foramen rotundum, l—Foramen ovale, m—Foramen spinosum, n—Foramen jugulare, o—Hypoglossal Canal.
Presigmoid approach that uses a mastoidectomy and skeletonization of the sigmoid sinus
1—f, Retrolabyrinthine;
Serviceablehearingincludesapuretoneaverage threshold better than 50 dB and/or speech discrimination greater than 50% (50/50 rule), and may favor the use of hearing-sparing approaches depending on tumor size and location (e.g. middle fossa, retrosigmoid, retrolabyrinthine). Use of other approaches sacrifices hearing, hence other criteria such as surgical exposure gained and risk of facial nerve injury become prime considerations.
Includes drilling the posterior and superior external auditory canal and sacrificing middle ear structures and inner ear (cochlea), and rerouting the facial nerve to provide access to the anterior cerebellopontine angle, petrous apex, and ventral brainstem.
2—h, Transcochlear
Serviceablehearingincludesapuretoneaverage threshold better than 50 dB and/or speech discrimination greater than 50% (50/50 rule), and may favor the use of hearing-sparing approaches depending on tumor size and location (e.g. middle fossa, retrosigmoid, retrolabyrinthine). Use of other approaches sacrifices hearing, hence other criteria such as surgical exposure gained and risk of facial nerve injury become prime considerations.
