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History of severe headache and an empty sella
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 Jeena Sandeep |
 Stephanie L. Lee |
A 37-year-old man was referred for the evaluation of an abnormal pituitary MRI scan with a question of the appropriate interval of time to repeat his pituitary imaging. When he was 20 years old, he developed rapid onset of nausea, vomiting and headache 2 to 3 days after a complicated wisdom tooth extraction. He had a CT scan at that time that, by his report, was unremarkable. His symptoms, however, persisted for about 6 weeks when he developed additional symptoms of fatigue, excessive thirst and weight loss. A head MRI at that time reportedly showed a pituitary tumor that was less than 10 mm in height. He was not given any medications at that time, but surgery was recommended. The patient opted for close monitoring rather than surgery. Gradually, his symptoms resolved over the next 8 to 12 months.
The patient had serial pituitary MRI scans every year, which reportedly showed a gradual decrease in the size of the pituitary gland. The first scans that were obtained for our review in 2004 and 2008 did not reveal a pituitary tumor, but demonstrated a partially empty sella (Figure 1). The anterior pituitary was small with normal homogeneous contrast enhancement with the infundibulum shifted to the left. The infundibulum enhanced normally after contrast administration. No mass was seen in the sella.
Endocrine testing between 2003 and 2008 documented normal levels of thyroid-stimulating hormone 1.65 mU/L; free thyroxine 1.2 ng/dL; adrenocorticotropic hormone (ACTH) 29 pg/mL; cortisol 10.24 mcg/dL; growth hormone 1.3 ng/mL; insulin-like growth factor I 260 ng/mL; follicle-stimulating hormone 2.6 mU/mL; luteinizing hormone 4 mU/mL; prolactin 4.1 ng/mL; and testosterone 457 ng/dL. Interestingly, his past medical history revealed that the patient had experienced a growth spurt with growth of 3.5 inches at age 19 years, with a current height of 6’7� (200.7 cm). His parents and siblings were of “normal height.�
Empty sella syndrome
Empty sella turcica is defined as a sella that is not entirely filled with pituitary tissue and is completely or partly filled with cerebrospinal fluid that has herniated from the suprasellar subarachnoid space into the sella turcica through a defect in the diaphragma sellae (Figure 1). The pituitary stalk is stretched to the compressed pituitary gland.
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Cerebrospinal fluid (CSF) has herniated from the suprasellar subarachnoid space into the sella turcica though a defect in the diaphragma sellae. The pituitary stalk (infundibulum) is stretched to the flattened pituitary gland in the left side of the sella in panel A. The infundibular enhances normally after gadolinium contrast in both the coronal (A) and sagittal (B) views. The sella appears to be “empty,� but the pituitary is flattened along the sphenoid bone and the sella is filled with CSF. Photos courtesy of: Stephanie L.
Lee, MD, PhD |
There are two types of empty sella — primary empty sella (PES) and secondary empty sella. PES results from congenitally incompetent diaphragma sellae (opening in the dura that the infundibulum passes through into the sella; Figure 2A). Defects in the diaphragmatic sellae allow herniation of the arachnoid membrane and cerebrospinal fluid into the sella turcica (Figure 2B) associated with flattening of the pituitary gland, which gives the appearance of a partially empty sella. Secondary empty sella may occur as a result of benign intracranial hypertension or pituitary disease, such as a tumor or lymphocytic hypophysitis, and its subsequent resolution either spontaneously or by surgery, radiation or apoplexy. In long-standing cases, sellar enlargement occurs probably because of persistent transmission of intracranial pressure or prior enlargement of the sella turcica from a pituitary adenoma.
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Green: Anterior pituitary gland. White: Posterior pituitary and pituitary stalk (infundibulum). Blue: Dura. Red: CSF in the supersellar cistern and herniating into the sella (B). Grey: Sphenoid bone. Yellow arrows: Normal dura opening (diaphragma sellae). Green arrows: Enlarged diaphragma sellae in primary empty sella syndrome. |
MRI findings of empty sella syndrome include an enlarged or normal-sized sella with either absent or displaced pituitary tissue, marked by the displacement of infundibulum (Figure 1). Usually, the pituitary gland is flattened along the floor of the sella and may not be seen on MRI or CT scans but typically retains normal function.
Related symptoms
Empty sella is usually free of clinical symptoms, but at times is associated with headache (50%), visual field defects (1.6% to 15%), nontraumatic cerebrospinal fluid rhinorrhea and pituitary hormone abnormalities (25% to 55%). Evaluation of empty sella involves imaging of the brain and assessing for hormonal abnormalities and visual field defects. Among hormonal abnormalities, GH deficiency and mild hyperprolactinemia have also been reported in 10.3% to 32% and 4% of patients, respectively. Global hypopituitarism is rare and occurs in about 2% to 16% of patients with empty sella. Progression of empty sella causing global hypopituitarism, which requires complete hormonal replacement, is very rare and was seen in one of 58 patients who were followed for an average of 48 months. Isolated deficiencies of ACTH, TSH and antidiuretic hormone (ADH or vasopressin) can occasionally occur. Diabetes insipidus is thought to be related to pituitary stalk compression or torsion by herniation of the arachnoid and cerebrospinal fluid into the sella. Visual field defects or other visual abnormalities seen in the case of PES are a result of posterior dislocation of optic nerve and chiasm, optic nerve compression between optic foramen and the anterior part of pituitary fossa, or partial prolapse of optic tracts into the sella with optic nerve and optic chiasm strain.
It is not clear if this patient had primary or secondary empty sella syndrome. One speculation is that he had a GH-secreting tumor that was responsible for his excessive growth spurt and height with apoplexy, headache and vomiting after his surgical procedure. His complaint of several months of polydipsia with polyuria is not documented, but may have been a result of pituitary stalk compression and a relative lack of vasopressin secretion and partial central diabetes insipidus. His symptom of excessive thirst would have resolved with resolution of the apoplexy-related pituitary enlargement and relief of the pituitary stalk compression as documented on his serial pituitary imaging scans.
We recommended an evaluation of his pituitary-adrenal axis with cosyntropin, overnight metyrapone tests and formal visual field testing. It is unlikely that pituitary dysfunction would occur with time, but periodic endocrine and visual field exams were recommended. He was advised that he did not require an annual pituitary MRI scan; however, he should repeat the pituitary MRI with gadolinium contrast only if new symptoms or hormonal abnormalities are noted.
Jeena Sandeep, MD, is a resident in internal medicine at Mount Auburn Hospital in Cambridge, Mass. Stephanie L. Lee, MD, PhD, is associate chief in the section of endocrinology, diabetes and nutrition and associate professor of medicine at Boston Medical Center.
For more information:
- Buchfelder M. Horm Metab Res. 1989;21:573-576.
- De Marinis L. J Clin Endocrinol Metab. 2005;90:5471-5477.
- Komada H. Endocr J. 2009;56:585-589.
- Robinson DB. Arch Intern Med. 1992;152:1920-1923.