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E20 Endocrinology
Pituitary Gland Toronto Notes 2019
• respiratorydisease(TB,pneumonia,empyema)
• drugs(SSRIs,vincristine,chlorpropamide,cyclophosphamide,carbamazepine,nicotine,morphine,
DDAVP, oxytocin)
Clinical Features
• symptomsofhyponatremia:headaches,nausea,vomiting,musclecramps,tremors,cerebraledemaif severe (confusion, mood swings, hallucinations, seizures, coma)
Treatment
• treatunderlyingcause,fluidrestriction(800-1000mL/day),vasopressinreceptorantagonists(e.g. tolvaptan, conivaptan), demeclocycline (antibiotic with anti-ADH properties, rarely-used), and furosemide
Pituitary Pathology
PITUITARY ADENOMA (see Neurosurgery, NS14)
Clinical Features
• localmasseffects
■ visual field defects (bitemporal hemianopsia due to compression of the optic chiasm), diploplia (due
to oculomotor nerve palsies), headaches; increased ICP is rare • hypofunction
■ hypopituitarism • hyperfunction
■ PRL (galactorrhea), GH (acromegaly in adults, gigantism in children), ACTH (Cushing’s disease = Cushing’s syndrome caused by a pituitary tumour)
■ tumours secreting LH, FSH, and TSH are rare
Investigations
• radiologicalevaluation(MRIisimagingprocedureofchoice) • formalvisualfieldtesting
• hypothalamic-pituitaryhormonalfunction
HYPOPITUITARISM
Etiology (The Eight Is)
• Invasive
■ pituitary tumours, craniopharyngioma, cysts (Rathke’s cleft, arachnoid, or dermoid), metastases
• Infarction/hemorrhage
■ Sheehan’s syndrome (pituitary infarction due to excessive post-partum blood loss and hypovolemic
shock)
■ pituitary apoplexy (acute hemorrhage/infarction of a pituitary tumour; presents with sudden
loss of pituitary hormones, severe headache, and altered level of consciousness; can be fatal if not
recognized and treated early) • Infiltrative/inflammatory
■ sarcoidosis, hemochromatosis, histiocytosis • Infectious
■ syphilis, TB, fungal (histoplasmosis), parasitic (toxoplasmosis) • Injury
■ severe head trauma • Immunologic
■ autoimmune destruction • Iatrogenic
■ following surgery or radiation • Idiopathic
■ familial forms, congenital midline defects
Clinical Features
• symptomsdependonwhichhormoneisdeficient:
■ ACTH: fatigue, weight loss, hypoglycemia, anemia, hyponatremia, failure to thrive and delayed
puberty in children
■ GH: short stature in children, adults exhibit increased fat and decreased lean body mass, decreased
BMD, fatigue
■ TSH: tiredness, cold intolerance, constipation, weight gain
■ LH and FSH: oligo- or amenorrhea, infertility, decreased facial/body hair and muscle mass in men,
erectile dysfunction, delayed puberty
■ Prolactin: inability to breastfeed
■ ADH: symptoms of diabetes insipidus (extreme thirst, polydipsia, hypernatremia)
■ Oxytocin: usually asymptomatic – only needed during labour and breastfeeding
SIADH vs. Cerebral Salt Wasting (CSW)
CSW can occur in cases of subarachnoid hemorrhage. Na+ is excreted by malfunctioning renal tubules, mimicking findings of SIADH; hallmark is hypovolemia
Important Deficiencies to Recognize are:
• Adrenal insufficiency
• Hypothyroidism
Concurrent adrenal insufficiency and hypothyroidism should be treated with glucocorticoids first and then with thyroid hormone to avoid adrenal crisis
The Pituitary Hormones
Order they are usually lost with compression by a mass:
“Go Look For The Adenoma Please”
GH, LH, FSH, TSH, ACTH, PRL + posterior pituitary hormones: ADH and oxytocin