HEALTHWATCH
Gateway to the brain
DR. G. SUNDHAR KRISHNAN AND DR. P. KANTHAMANI
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The trans-nasal approach, particularly with the endoscope, has revolutionised the treatment of pituitary tumours.
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Problems with vision: the full field of vision;
THE pituitary gland is the master gland that regulates the thyroid gland, adrenal gland and the sexual organs in the body. Pituitary tumours occur as a result of overgrowth of cells in the pituitary gland. These tumours may often be present for years without symptoms.
The pituitary gland lies in the sella, a depression in the sphenoid bone, just behind the eye sockets. The gland is connected with the brain above by the pituitary stalk. On the sides are the two cavernous sinuses, which contain the two carotid arteries and the nerves responsible for movement of the eyelids, eyes and awareness of facial sensation. The two optic nerves meet above the sella at the optic chiasm.
Symptoms
In the event of pituitary tumours, there can either be an overproduction or underproduction of thyroxine, cortisone or the sex hormones.
The symptoms, which include lactation, alteration in menstrual cycle, impotence or lack of sexual drive, are most common. Less commonly, increased production may cause gigantism in young patients and acromegaly or enlargement of hands, feet and facial structures in older patients. Headaches can be occasional or sudden and severe in the event of a bleed.
If the tumour extends out of the sella, it can produce symptoms of compression of optic nerve, chiasm or cranial nerves in the cavernous sinus. This is when the patient experiences visual problems.
Examine the eye
Often the patient first goes to an ophthalmologist but a routine eye examination will return normal results. Additional visual field examination by auto perimeter alone will detect the field defects. The pattern of these field defects then gives a clue to the location of the intracranial abnormality.
Then one can proceed with further radio imaging, neurological and endocrinological evaluation. Visual acuity per se is not affected initially. Radio imaging is useful for early detection while visual field charting is indispensable
Case study
A 54-year-old gentleman was not able to see on the sides for two to three years and had difficulty in reading with glasses. Eye examination and visual field charting showed absent vision in the right half of visual field of the right eye and the left half of the field in the left eye. Radio imaging showed a pituitary tumour extending above the sella compressing the chiasm.
After a thorough check-up and discussions between an endocrinologist, neurosurgeon, neuro-ophthalmologist and radiologist, surgical intervention was decided upon. The current surgical approach is through the nose — either with a microscope or a nasal endoscope. The neurosurgeon-ENT surgical team took advantage of the proximity of the pituitary gland in the sella to the sphenoid sinus through the nose.
No vision in the left half.
There is no need to open the skull or suturing. The patient can be discharged in a day or two.
The angled endoscope offers better visualisation of the extent to which the tumour has been cleared, which is vital to prevent recurrence. This needs surgical expertise and is relatively safe even when the pituitary tumour extends above and/or to the cavernous sinuses.
After surgery
Radiotherapy is required after surgery if any remnant of the tumour is left because of proximity to vital structures, or if it recurs. Hormonal replacement is taken care of by the endocrinologist. Postoperative follow-up is recommended for an adequate period with all the concerned doctors.
No vision in the right half.
The advantages of this method of treatment are: Scarless surgery, minimal hospital stay; minimum discomfort; better disease clearance; less recurrence; and lastly economical.
The authors are with Krishna Eye and ENT Hospitals, Chennai. E-mail: cleopatra_sk@yahoo.com
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