PITUITARY TUMORS
Pituitary tumors represent various cell types, representing an overgrowth of
1. Eosinophilic cells-
2. Basophilic cells or
3: Chromophobic cells (i.e. Cells with no affinity for either eosinophilic or basophilic stains).
Eosinophilic tumors: If they develop early in life, result in gigantism the person may be over 7 feet tall and large in all proportions, yet so weak and lethargic that he can hardly stand.
If the disorder begins during adult life, the excessive skeletal growth occurs only in the feet, the hands, the superciliary ridges, molar eminences, the nose and the chin called acromegaly
Enlargement, moreover, is not confined to the skeleton but involves every tissue and organ of the body.
Basophilic tumors give rise to the so-called Cushing's syndrome with features largely attributable to hyperadrenalism including masculinization an amenorrhea in females, truncal obesity, hypertension, osteoporosis and polycythaemia.
Chromophobic tumors: comprise 90% of pituitary tumors, produce no hormones but destroy the rest of the pituitary gland, causing hypopituitarism. Patients are obese and somnolent, exhibit fine, scanty hair, dry, soft skin; pasty complexion; and small bones. They also experience headaches, loss of libido and visual defects progressing to blindness. Other symptoms include polyuria, polyphagia, a lowering of the basal metabolic rate and a subnormal body temperature.
Causes
Unknown. Malignancy in pituitary tumors is rare,
Clinical Manifestations
1. "Mass effects" - effects of tumor or surrounding structures.
a. Headache
b. Nausea and vomiting (in some cases)
Impairment of cranial nerves II, III, IV & VI on testing because of bilateral hernianopsia that results from pressure on the optic chiasm and visual disturbances such as visual field defects and diplopia.
2. Endocrine effects-effects of hormone imbalances caused by tumor.
Hyperpituitarism gigantism (child), acromegaly (adult), infertility and galactorrhoea (female), Cushing's disease, hyperthyroidism, gonadal dysfunction.
Hypopituitarism shortness of stature (Child), silent (adult), postpartum lactation failure, adrenocortical insufficiency, hypothyroidism and hypogonadism.
Diagnostic Evaluation
1. Skull films
2 CT Scan, MRI
3. Serum hormone levels
4 [Provocative testing to detect hormone secretion abnormalities of the pituitary such as glucose tolerance test and DST)
Medical Management
1 Hypophysectomy-removal of pituitary gland.
a Frontal craniotomy [uncommon approach except where tumor occupies broad area]..
b Transsphenoidal hypophysectomy [direct approach through the sinus and nasal cavity to sella turcica].
2. Other methods of pituitary ablation.
a. Cryogenic destruction or stereotaxic radiofrequency coagulation.
b. Radiation therapy
c. Drug therapy Bromocriptine (Parlodel) for prolactinoroas and in some instances, GH (Growth hormone) replacement therapy for hypopituitarism. secreting tumors, hormone.
Complications
1. Hypothyroidism and adrenocortical insufficiency after ablation [requiring hormone replacement].
2. Menstruation ceases and infertility [occurs almost always after total or nearby total ablation].
3. Transient or permanent DI after surgery.
4. Without treatment death or severe disability caused by stroke, blindness or imbalances of ACTH, TSH or ADH
Nursing Interventions
1. Provide emotional support and answer questions about treatment options.
2. Prepare patient for surgery and other treatment.
3. Teach patient the nature of hormonal deficiencies after treatment and the purpose of replacement therapy.
4. Instruct the patient of the early s/s of cortisol or thyroid hormone deficiency or excess and the need to report them.
5. Advise patient on temporary limitation in activities.
6. Teach patient the need for frequent initial follow-up visits and lifelong medical management when on hormonal therapy
7. Post Op [Transsphenoidal hypophysectomy carried out through nasal cavity, sphenoid sinus and into sella turcica] monitor vital signs, visual acnity and neurologic status.
Urine output and specific gravity and serum e and osmolality are monitored for DI or SIADH.
Drainage from nose is monitored for signs of infection or CSF leak Pre-op. assess for sinus infection and treat
Hydrocortisone (Corter) may be given preoperatively because the source of ACTH is being removed.
