empty sella syndrome part II screening and diagnostic testing

Aquino, Felix SP
Sarmiento, Noel



II Screening and Diagnostic Testing

Empty sella syndrome is most often discovered during radiological imaging of the brain where spinal fluid is found within the space created for the pituitary.

However, many of these cases the empty sella is detected as a coincidental finding on an imaging study ordered for some other reason. Only occasional diagnosis is made because empty sella syndrome was suspected from some type of endocrinological abnormality suggesting hypopituitarism. (National Institute of neurological disorders and stroke, 2008).

Empty sella syndrome is always diagnosed by some type of imaging study of the brain (x ray, CT scan, or MRI). The confirmation of empty sella with x-rays used to be done by performing the pneumoencephalography or metrizamide cisternography, which are no longer required with the advent of better imaging modalities.

Several computed tomographic scan studies have described empty sella in children with hypothalamic-pituitary disorders. Eight cases of primary empty sella diagnosed on pneumoencephalography (PEG) were examined using computed tomography (CT). The diagnosis was made correctly in every case and it was possible to differentiate an empty sella from a pituitary adenoma. Slices 5 mm thick and an overlapping technique were necessary because of the small volume of the tissues analysed. PEG does not seem to be necessary in most cases of suspected intrasellar cisternal herniation, and it is needed only in the difficult case in which the clinical picture and the CT finding are not in harmony. ( Ketonen & Kuuliala, 2004)

CT scanning was found very useful in the assessment of the size of the tumor, its suprasellar or parasellar extension and response to therapy, and in differential diagnosis of tumor and empty sella. Use of computerized tomography scans will show the pituitary fossa to be occupied largely by substance of CSF or water density rather than a normal gland in patients with empty sella syndrome. According to Valenta et al, (2003), CT scanning is the most advanced technique in the diagnosis of anatomic pituitary abnormalities and it should replace the traditional invasive diagnostic procedures.

Magnetic resonance imaging, however, is a more precise technique for visualizing the intrasellar content, such as the stalk and pituitary lobes (Cacciari, et al 2004). It is useful in evaluating ESS and differentiating it from other disorders that produce an enlarged sella. (Radgay, 2009).It can also readily confirm the diagnosis of an empty sella. On T1 sagittal MR images, extension of CSF into the sella is easily identified and remaining gland is compressed along the floor. Typical central position of the infundibulum is a useful sign in an empty sella which helps to rule out a cystic lesion in the suprasellar region. (Agarwal et al, 2001)

According to Zhang, et al.(2005), MRI could reveal the correct diagnosis with its multi-oriented characteristics, and it is recommendable as the first choice of imaging procedure in PES.Compared to CT-scan, MR imaging findings were homogenous and showed the anterior pituitary gland to be extremely hypoplastic,. MR imaging has become the method of choice for visualization of the pituitary gland and hypothalamic area, diagnosis of growth hormone deficiency, and differential diagnosis of a variety of disorders associated with short stature in children. A possible mechanism might include severe hypoplasia of the anterior pituitary gland, with empty sella, that is often associated with ectopia of the posterior lobe and either the absence of or hypoplasia of the pituitary stalk. Furthermore, the underlying mechanisms of such pituitary anomalies should also be delineated. Empty sella is considered to be an epiphenomenon of pituitary hypoplasia, a sort of focal dysraphic state, with no evidence of sellar enlargement and primary compression by cerebrospinal fluid.(Fofanova, 2000)

In empty sella syndrome, most patients have no pituitary dysfunction, but partial or complete pituitary insufficiency has been reported. The discovery of an empty sella needs to be followed by an endocrine evaluation to determine whether there is any associated pituitary dysfunction. (Hamrahian, 2004).

To establish the diagnosis of hypopituitarism (partial or complete) and to determine thehypophyseal cause of dysfunction, measurement of following hormones are required – serum thyrotropin and T4, corticotropin and cortisol, LH and testosterone, basal and stimulated growth hormone and prolactin level. (Agarwal et al, 2001).Usually, the hormonal profile is normal in patients with empty sella. However, mild hyper-prolactinaemia (usually <100 μg/l) with or without galactorrhoea occurs in approximately 15% of patients. An elevated level of prolactin to patient may interfere with the normal function of the testicles or ovaries. (Healthscout, 2009).

In addition, sometimes tests for high pressure in the brain will be done, such as: examination of the retina by an ophthalmologist and lumbar puncture.

Reference:

Agarwal J. et al.. (2001). Empty Sella Syndrome. Journal, Indian Academy of Clinical Medicine Vol. 2, No. 3

Cacciari, E., Zucchini, S., Ambrosetto, P., Tani, G., Carla, G., Cicognani, A., Pirazzoli, P., Sganga, T., Balsamo, A., & Cassio A.(2004). Empty sella in children and adolescents with possible hypothalamic- pituitary disorders. Retrieved on February 16, 2010 at http://jcem.endojournals.org/cgi/content/abstract/78/3/767

Fofanova, O. Takamura, N. Kinoshita, E. Vorontsov, E. Vladimirova, V. Dedov, I. Peterkovam, V.and Yamashita, S. 2000, MR Imaging of the Pituitary Gland in Children and Young Adults with Congenital Combined Pituitary Hormone Deficiency Associated with PROP1 Mutations, Retrieved on Frebruary 16, 2010 at http://www.ajronline.org/ cgi/content/full/174/2/555

Hamrahian, A.(2004). Pituitary Disorders. Retrieved on February 16, 2010 at http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/endocrinology/pituitary-disorders/

Healthscout.(2009).Empty sella syndrome.Retrieved on February 16, 2010 at http://www.healthscout.com/ency/1/000349.html

Ketonen L, & Kuuliala I. (2004). Diagnosis of primary empty sella syndrome by computed tomography. Retrieved on February 16, 2010 at http://www.medscape.com /medline/abstract/517991

Radgay. (2009). Empty Sella Syndrome. Retrieved on February 16, 2010 at http://www.radgray.com/mri/mri-articles/empty-sella-syndrome.html

Valenta, L.,Sostrin, R., Eisenberg, H., Tamkin, J. & Elias, A.(2003). Diagnosis of pituitary tumors by hormone assays and computerized tomography. Retrieved on February 16, 2010 at http://www.medscape.com/medline/abstract/7091157

Zhang, J., Zhang, L.,Song H., et al.(2005). MR Imaging of Primary Empty Sella Syndrome.Retrieved on February 16, 2010 at http://en.cnki.com.cn /Article_en /CJFDTOTAL-SYYJ200501011.htm

National Institute of neurological disorders and stroke. (2008). Empty Sella Syndrome Retrieved on February 16, 2010 at http://www.ninds.nih.gov /disorders/emptysella /emptysella.htm


[center][center]