hypopituitarism Flashcards
approach to dx and management
-The goal is always to maintain homeostasis
-Using physiology and pathophysiology to explain the symptoms and signs.
-What if any, are the risk factors, that might result in the pathology?
-How would you approach treating the symptoms and signs?
-What does follow up entail?
-How would you explain it to the patient?
hypopituitarism
-Endocrine deficiency syndromes
-Partial or complete loss of Ant. Pit. Function
-With or without associated mass lesions
-Various clinical features – depends on hormones affected
-Diagnosis:
-Imaging tests
-Measurement of pituitary hormone levels -> Basally and after various provocative stimuli
-Treatment d/o cause:
-Removal of any tumor/suppression medications
-Administration of replacement hormones
pituitary tumors
-adenoma
-craniopharyngioma
infarction or ischemic necrosis
-hemorrhagic infarction (pituitary apoplexy)
-shock- sheehan’s syndrome
-vascular thrombosis or aneurysm
inflammatory processes
-Meningitis
-Pituitary abscess
-Sarcoidosis
infiltrative disorders
-Hemochromatosis
-Langerhans’ cell histiocytosis- (Hand-Schüller-Christian disease)
primary hypopituitarism
-Pituitary tumors
-Infarction or ischemic necrosis
-Inflammatory processes
-Infiltrative disorders
-Iatrogenic - removal
-Autoimmune dysfunction
secondary hypopituitarism
-Hypothalamic tumors
-Inflammatory diseases
-Neurohormone deficiencies of the hypothalamus
-Iatrogenic
-Trauma
mortality/morbidity of hypopituitarism
-Descending order of importance
-ACTH > TSH > GH > FSH/LH
-Deficiency of ACTH with adrenal crisis or TSH with myxedema may be life threatening -> Sudden loss of production may result in more profound morbidity than slowly progressive deficiency
-GH deficiency causes more morbidity in children than in adults
-Gonadotropin deficiency with hypogonadism may cause morbidity insidiously
-Morbidity is more profound in congenital hypopituitarism
symptoms and signs of hypopituitarism
-depends on underling disorder and specific pituitary hormones (deficient or absent)
-onset- usually insidious -> may not be recognised by the pt
-occasionally onset is sudden or dramatic
-MC GH is lost first -> then gonadotropins -> then TSH and ACTH
-ADH deficiency- rare in primary pituitary ds -> common with stalk and hypothalamic lesions
-panhypopituitarism
other presenting features of hypopituitarism
-attributable to the underlying cause
-a pt with space occupying lesion may present with headaches or visual field deficits
-a pt with large lesions involving the hypothalamus may present with polydipsia and syndrome of SIADH
investigation
-ideally MRI
-high resolution CT
-with or without contrast (R/O structural abnormalities)
-if deficiency +ve -> potentially life threatening:
-coritsol- in ACTH deficiency
-T4, TSH:
-both are low in generalized hypopituitarism
-as opposed to primary thyroid deficiency -> increase TSH and low T4
urgent treatment
-acute adrenal insufficiency
-requires immediate tx with glucocorticoids -> 100mg hydrocortisone IV, then 5-100mg every 6h and fluid replacement
-immediate referral for visual field loss is required -> classically a bitemporal hemianopsia
-refer immediately to an experienced neurosurgeon
-pituitary apoplexy:
-sudden enlargement of the pituitary, owing to hemorrhage or necrosis, with associated function loss
-Risk of catastrophic adrenal failure, visual field loss, and raised intracranial pressure
-Treat as above
tx of hypopituitarism
-Hormone replacement of the hypo-functioning target glands
-Tumor
-Transsphenoidal removal or irradiation
-Dopamine agonist - often the initial treatment of prolactinoma
-Pituitary apoplexy
-Immediate surgery warranted if
-Visual field disturbances
-Oculomotor palsies
-Somnolence progresses to coma because of hypothalamic compression
-Although management with high-dose corticosteroids and general support may suffice in a few cases, transsphenoidal decompression of the tumor should generally be undertaken promptly
DDx of generalized hypopituitarism
-anorexia nervosa- maintenance of secondary sexual characteristics! (this differentiates it) despite amenorrhea -> increased levels of basal growth hormone (low IGF) and high cortisol
-alcohol liver disease of hemochromatosis- evidence of liver disease -> lab testing
-myotonia dystrophica- progressive weakness, premature balding, cataracts, facial features of accelerated aging -> lab testing
-polyglandular autoimmune disease
hypopituitarism in children -sx,dx,tx
-Pituitary tumor - Craniopharyngioma
-Langerhans’ cell histiocytosis
-Midline defects -Cleft palate
-Therapeutic radiation of the CNS
-Hereditary – 5%
-Idiopathic
-Presentation:
-Height is below the 3rd percentile, and growth velocity
-Skeletal maturation > 2 yr behind chronologic age
-Fails to begin pubertal development
-Assess bone age
-X-ray of the left hand
-Skeletal maturation usually delayed to the same extent as height
-CT or MRI of brain
-R/o calcifications & tumors
-Mid to late childhood, insulin-like growth factor 1 (IGF-1) levels measured
-Treatment
-Surgery
-GH replacement
-Other hormones need to be replaced as well (Cortisol, Thyroid, gonadal sex steroids)
GH deficiency
-clinically undetectable in adults
-usually, asymptomatic
-decreased energy
-?? accelerates atherosclerosis
-hypopituitarism in children
-abnormally slow growth
-short stature with normal proportions
ACTH defieicny
-hypoadrenalism:
-fatigue
-weakness
-wt loss
-hypotension
-hypoglycemia
-intolerance to stress and infection
-decreased axillary and pubic hair
-no hyperpigmentation
-plasma and urinary steroid levels are low
-rise to normal after ACTH replacement
-tx is with cortisol replacement
ACTH investigations
-cortisol levels alone are not reliable indicators of ACTH-adrenal axis function
-One of several provocative tests
-Standard ACTH simulation test
-Safer & less labor intensive
-Synthetic ACTH (cosyntropin)
-Administered – IV/IM
-Plasma cortisol response measured 30 and 60 min later
-Cortisol should rise significantly; Normal response is cortisol >21 g/dL and aldosterone response of >4 ng/dL above baseline
-Insulin Tolerance Test
-Hazardous test in patients with severe documented:
-Panhypopituitarism
-Diabetes mellitus
-Elderly
-Contraindicated in those:
-Coronary artery disease
-Epilepsy
lack of LH and FSH
-in children- delayed puberty, short stature
-premenopausal women:
-amenorrhea
-reduced libido
-regression of 2ndary sexual characteristics
-infertility
-men:
-ED
-testicular atrophy
-reduced libido
-regression of 2ndary characteristics
-decreased spermatogenesis with consequent infertility
kallmann’s syndrome
-Specific lack of gonadotropin-releasing hormone (GnRH)
-Associated with midline facial defects
-Anosmia
-Cleft lip or palate
-Color blindness
-hypogonadism and anosmia or hyposmia
-1/2 of these pts have unilateral renal agenesis (missing a kidney)
-some pts also exhibit cryptochidism (testes dont descend), micropenis, color blindness, sensorineural deafness, cerebellar ataxia, cognitive problems, bimanual synkinesis (mirror movement), cleft lip or palate, or high arched palate
-some affected women have menarache followed by secondary amenorrhea
panhypopituitarism
-simmond’s syndrome
-involvement of all pituitary hormones -> only one or more pituitary hormones are often involved resulting in partial hypopituitarism
panhypopituitarism: sheehan’s syndrome**
-affects postpartum women
-loss of blood after delivery
-after delivery of placenta uterus can contract fully
-when placenta isnt fully delivered, laceration,
-amount of blood loss depends on if pt is anemic or not
-pituitary does get enough blood -> often panhypopituitarism
-pituitary necrosis from hypovolemia and shock- peripartum period
-lactation does not start after childbirth
-fatigue
-loss of 2ndary sexual characteristics- loss of pubic and axillary hair (DIFFERENTIATES FROM ANOREXIA)
pituitary apoplexy
-adrenal crisis
-sudden onset
-pituitary outgrows the blood supply
-sx complex caused by hemorrhagic infarction of either a normal pituitary gland or, more commonly a pituitary tumor
-symptoms:
-severe headache
-stiff neck
-fever
-visual field defects
-oculomotor palsies
-resulting edema due to compression of hypothalamus- somnolence or come
-varying degrees of hypopituitarism may develop suddenly- many present with vascular collapse bc of deficiency ACTH and cortisol
-CSF +/- blood
-MRI- hemorrhage
