Evaluation and Management of Selected Pituitary Issues Dana Erickson, MD Neena Natt, MD Mayo Clinic College of Medicine Rochester, MN

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Mass Effects or Potential Mass Effects Anatomy

Cavernous sinus

Optic chiasm

Oculomotor nerve (III)

Posterior communicating artery

Trochlear nerve (IV)

Internal carotid artery

Abducens nerve (VI) Ophthalmic nerve (V1) Maxillary nerve (V2)

Hypophysis (pituitary gland) Sphenoidal sinus Nasopharynx

Coronal section through cavernous sinus

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Normal Pituitary on MRI Scan

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Causes of Sellar Masses • Pituitary adenoma (10% intracranial

neoplasms; microadenomas 1 cm)

• Cysts (Rathke’s cleft, arachnoid cysts) • Craniopharyngioma • Meningioma • Lymphocytic hypophysitis

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Causes of Sellar Masses • Malignancies Primary (germ cell tumors, chordoma, lymphoma, pituitary carcinoma) Metastases (breast, lung, others)

• Infiltrative disorders • Pituitary hyperplasia • Infections, AV fistula

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Pituitary Tumors Discovered

• Incidentally • Clinical evidence of mass symptoms, or hormonal excess or deficiency symptoms

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Genetics of Pituitary Tumors Possible genes involved in certain tumorigenesis

• MEN1 • Gs-alpha • PTTG • FGF receptor 4

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Pituitary Tumors Hormonal deficiencies • Anterior failure: ACTH, LH, FSH, TSH, GH • Posterior failure: ADH Hormonal excess • Separately (prolactin, TSH, ACTH, GH) • Combination of hormonal overproduction

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Sellar Masses Mass effect

• Headaches • Chiasmal compromise • Cranial nerve palsies • CSF leak

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Macroadenoma

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Pituitary Microadenoma on MRI Scan

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Pituitary Tumors After careful hormonal evaluation treatment strategies depend on

• Presence of mass effect • Hormonal hypersecretion • Hormonal deficiencies

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Pituitary Tumors Primary therapy could include

• Neurosurgery • Observation • Medical therapy (prolactinoma, some cases of acromegaly)

• Radiation therapy (rarely)

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Surgical Goals for Pituitary Tumors 1. Reverse or prevent mass effect 2. Reverse hormone deficiency 3. Normalize hormone overproduction 4. Minimize morbidity 5. Prevention of tumor recurrence 6. Tissue for pathologic diagnosis

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Transsphenoidal Pituitary Surgery • Sublabial transseptal approach

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Transsphenoidal Pituitary Surgery • Transnasal endoscopic approach

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Pituitary tumor Sphenoid sinus Sphenoid sinus ostium

Middle turbinate

Septum

Choana

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Transseptal

Transnasal

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Transseptal Pit

Transnasal Sphenoid sinus

Pit

Maxillary sinus

10°

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Endoscopic vs Sublabial • No external incision

• Sublabial incision

• Nasal septum intact

• Septum removed/replaced

• No postop nasal packing

• Postop packing 3-5 days

• Operating microscope

• Operating microscope

• Smaller operating field

• Larger operating field

• 10 degrees off center

• Field at 90 degrees

• Endoscopic visualization

• N/A

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Procedure Duration and Postoperative Hospitalization: Endoscopic vs Standard Duration (hr or days)

6

Standard Endoscopic 4.4

4

3.4

* 2.7

4.5 * 3.6 ** 2.6

2

0 OR time (hr)

Anes time (hr)

Hosp stay (days)

* P50%, available for follow-up x 24 months

• Tumor not visible, or decreased by 50% by MRI

• More than 5 mm from optic chiasm Colao et al: NEJM, 2003

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Withdrawal of Dopamine Agonists Recurrence of prolactin elevation

• 24% idiopathic hyperprolactinemia • 31% microprolactinomas • 36% macroprolactinomas • No tumoral enlargement

Colao et al: NEJM, 2003

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Cabergoline Withdrawal • Extended study on 221 patients follow-up 24-96 months (29 exited after 36 months)

• Multiple regression analysis Nadir PRL levels Nadir maximal tumor diameter prior to withdrawal Maximal tumor diameter at Dx

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Cabergoline Withdrawal

Lack of recurrence after withdrawal (%)

100 Negative MRI

75 50

Positive MRI

25 P50% over 4-6 hours

• Plasma ADH measurement when serum hyperosmolar, if nephrogenic DI suspected

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Diabetes Insipidus in Hospital • Replace existing fluid deficit 50% over

24 hours with D5W if neurologically stable and serum Na 12 meq/L over 24 hours

• If serum Na >180 meq/L, patient obtunded and hypotensive give first NS

• Recalculate fluid deficit every 24 hours • Replace ongoing other H2O losses

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Diabetes Insipidus in Hospital • Distinguish polyuric phase of acute renal failure from Di

• For chronic DDAP therapy dose equivalencies • 1 µg iv or sq = 10 µg intranasal • 0.1 mg oral in evening Second dose of DDAV given when daytime DI recurrence verified biochemically 6 hours before scheduled evening dose

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Diabetes Insipidus as Outpatient • Polyuria >3 L (R/O DM, R/O primary

polydipsia), rate and severity of onset

• Water deprivation test to diagnose DI (partial, complete) and central vs nephrogenic form

• Evaluation of etiology

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Diabetes Insipidus as Outpatient Etiology • Recent neurosurgery, head trauma • Autoimmune (hypophysitis) • Infiltrative stalk processes: sarcoidosis, Wegener’s granulomatosis, histiocytosis-X • Malignancy (germinoma, lymphoma) • Hypothalamic tumors • Familiar forms • Idiopathic

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Diabetes Insipidus as Outpatient • Treatment with chronic DDAVP • Start at bedtime (intranasal 10 mcg • • •

DDAVP or oral 0.1 mg DDAVP) Repeat dose only for recurrence of polyuria 6 hours prior to scheduled evening dose Some patients with mild forms with intact thirst mechanism only drink to satisfy thirst Do not over treat (hyponatremia)

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