Pituitary Dysfunction Flashcards
(43 cards)
Anterior pituitary secretes which H?
6 hormones
Posterior pituitary secretes which H?
ADH (vasopressin)
Oxytocin
Higher CNS centers in pituitary gland regulation
Thalamus
Limbic system
RAS
Retina
Growth Hormone stimulatory factors
Sleep
Stress
Ghrelin
Protein/Arginine
HYPOglycemia
Growth H Inhibitory factors
Obesity/FFA
Glucocorticoids
Leptin
HYPERglycemia (OGTT to test for GH excess prod)
Excess H results in what?
- GH
- PRL
- ACTH
- TSH
- ADH
- GH - Acromegaly
- PRL - hypogonadism
- ACTH - Cushing’s disease
- TSH - Hyperthyroidism
- ADH - SIADH
Deficiency in H results in what?
- PRL
- FSH/LH
- ACTH
- ADH
- PRL - Failed lactation
- FSH/LH - Hypogonadism
- ACTH - Adrenal insufficiency
- ADH- Diabetes Insipidus
Hypothalamic-Pituitary - Target organ defect
Peripheral:
Primary disorder
- Target organ
Central:
Secondary Disorder
- Pituitary gland
Tertiary Disorder
- Hypothalamus
Hormone excess is assessed by _______ test.
Hormone deficiency is assessed by ______ test
Suppression test
- OGTT for GH suppression to confirm acromegaly
(give them glucose, hyperglycemia should inhibit GH)
Stimulation test
- Insulin tolerance test to eval ACTH and GH reserves
GH regulation
GHRH +
Somatostatin -
GH is pulsatile and acts at level of liver (Insulin-like growth factor: IGF-1)
Actions of GH
Acts on IGF-1 hormone
- Increase blood glucose
- Increase bone and cartilage mass/growth
- Increase protein synth/muscle mass
- Increase fat breakdown, TGA levels
- Increase Salt/H2O
Problems of GH excess
Gigantism:
- GH excess b4 puberty
(b4 closure of growth plates)
Acromegaly:
- GH excess after puberty
(after completion of linear growth)
*Elevated IGF-1 found, then do pituitary MRI (detected in >80% acromegaly)
Clinical presentation of Acromegaly (6)
- Acral/gacial changes
- HA
- Hyperhidrosis
- Oligo/Amenorrhea
- Obstructive sleep apnea
- HTN
Tx for acromegaly
- surgery
- medical
- somatostatin analog
- GH receptor antagonist - radiation therapies
Manifestations of adult growth hormone deficiency (GHD)
- Body composition
- Increased Fat deposition
- Decreased muscle mass, strength, exercise capacity - Bone strength
- increased bone loss and fracture risk - MEtabolic and cardiovascular effects
- Increased cholesterol levels
- increased inflamm and prothrombotic markers (CRP) - Psycological well being
- Impaired E and mood
- Quality of life
Dx of adult onset GHD (AoGHD)
Gold standard:
Insulin induced hypoglycemia
*Central adrenal insufficiency dx too
contraindications: elderly, h/o seizure disorder, CAD, or cerebrovascular disease
IGF-1 lvls are low
Stimulants of Lactotropes (and ultimately producing prolactin)
E2, TRH, Suckling,
DA is inhibitory
Causes of hyperprolactinemia
- Physiological
- Pregnancy, suckling, sleep, stress - Pharmacological
- Estrogens
- Antipsychotics, antidepressants, anti-emetics, opiates - Pathological
- Pituitary stalk interruption
- Hypothyroidism, chronic renal failure/liver failure, seizure
- prolactinoma
Prolactinoma common findins
at least 5 each
females 10: males 1
women:
- galactorrhoea
- menstrual irregularity
- infertility
- Impairs GnRH pulse generator
- MICROadenomas
men:
- galactorrhoea
- visal field abnormalities
- HA
- Impotence
- EOM paralysis
- anterior pit. malfxn
- MACROadenomas
Primary fxn of cortisol
- gluconeogenesis
- breakdown of fat and protein for glucose prod.
- control inflammatory rxns
*BIGFIB (319)
Complications in chronic cortisol excess
- changes in carb, prot, and fat metab
- peripheral wasting of fat/muscle
- central obesity, moon facies, fat pads
- osteoporosis
- diabetes
- hypertriglyceridemia - Changes in sex hormones
- amenorrhea/infertility
- excess hair growth
- impotence - salt and water retention
- HTN + edema - Impaired immunity
- Neuro cognitive changes
*BIGFIB (319)
Two types of cortisol excess
- ACTH dependent (70-75%)
2. ACTH Independent (25-30%)
Specific Signs and sx of CUshings syndrome
5
- Plethoric/moon facies
- Wide violaceous striae
(Abdominal, axillary) - Spontaneous ecchymoses
- Proximal muscle weakness
- early/atypical osteoporosis
(atraumatic rib fracture)
Is most cortisol bound or unbound?
bound - to transcortin
cortisol binding globulin - CBG