Page 426 - Medicine and Surgery

P1: FAW
BLUK007-11 BLUK007-Kendall May 25, 2005 8:5 Char Count= 0

422 Chapter 11: Endocrine system

Table 11.1 Common hormone secreting pituitary adenomas For other pituitary adenomas, transsphenoidal resec-
tion is the treatment of choice, with postoperative
Hormone producing
pituitary adenoma Clinical syndrome radiotherapy for patients where complete resection
has not been possible. Major postoperative compli-
Prolactin (60%) Hyperprolactinaemia cations include CSF leakage, meningitis or visual im-
(e.g. amenorrhoea and
subfertility in women) pairment, which are most frequent in patients un-
Growth hormone (20%) Acromegaly dergoing large resections. Transient diabetes insipidus
Gigantism or syndrome of inappropriate anti-diuretic hormone
Adrenocorticotrophic Cushing’s disease (SIADH) may also occur. Increasingly asymptomatic
hormone (10%)
pituitary adenomas are found at incidental imag-
ing. In elderly or infirm patients surgery may not be
Clinical features appropriate.
Pituitary adenomas produce symptoms through local All patients require regular assessment for hormone
pressuresuchasheadache,andvisuallossduetopressure deficiencies with replacement therapy used as neces-
on the optic chiasm (bilateral temporal heminanopia). sary.
Continuing growth disrupts other hormone secretion
and can result in hypopituitarism. Symptoms may also Hypopituitarism
resultfromtheeffectsofhormoneexcess(seeTable11.1).
Definition
Macroscopy Hypopituitarism is a clinical term referring to under-
Tumours less than 1 cm in diameter without enlarge- function of the pituitary gland. This may imply a defi-

ment of, or extension outside the pituitary fossa are ciency of single or multiple hormones.
defined as microadenomas.
Tumours larger than 1 cm in diameter are called

macroadenomas and may cause pituitary fossa en- Aetiology
The commonest causes are pituitary or hypothalamic
largement.
tumours, or secondary to pituitary surgery or cranial
Tumours ≥1–2 cm may extend outside the fossa to-

radiotherapy (see Table 11.2).
wards the hypothalamus and optic chiasm, laterally
into the cavernous sinus or downwards into the sphe-
noid sinus. Pathophysiology
Hypopituitarism may be primary due to destruction of
Investigations the anterior pituitary gland or secondary to a deficiency
A mass within the sella turcica (pituitary fossa) may of hypothalamic stimulation (or excess of inhibition).

be identified on plain skull X-ray.
MRI scanning using gadolinium contrast is the imag-

Clinical features
ing modality of choice. Microadenomas take up less
Symptoms and signs are related to the deficiency of hor-
contrast and macroadenomas take up more contrast.
mones (see Table 11.3). General symptoms of panhy-
Ifapituitarymassisidentified,hormoneassaysshould

popituitarism include dry, pale skin with sparse body
beundertakentoidentifyfunctioningadenomas.Test-
hair. On examination postural hypotension and brady-
ing also helps identify any associated hypopituitarism,
cardia may be found with decreased muscle power and
with stimulation or suppression testing where appro-
delayed deep tendonreflexes.
priate.
Management Investigations
Forprolactinomas medical treatment with a All functions of the pituitary should be assessed using

dopaminergic drug is the treatment of choice (see sec- basal levels, stimulation tests and suppression testing
tion on Hyperprolactinaemia, page 424). where appropriate.