Pituitary Flashcards
How can the causes of Cushing’s syndrome be divided?
ACTH and non-ACTH dependent Cushings
What is the the pathological cause of the symptoms in Cushings?
Excess cortisol production by adrenal cortex, also excess mineralocorticoid and excess androgen
What are some symptoms of Cushings syndrome?
- Weight increase
- Mood change
- Proximal weakness
- Gonadal dysfunction
- Acne
What are some signs of Cushings syndrome?
- Central obesity
- Plethora
- Moon face
- Buffalo neck hump
- Thin skin
- Bruising
- Pigmentation
- Hypertension
- Abdominal striae
- Osteoporosis
What are the key clinical features of Cushing’s syndrome?
Pigmentation (only ACTH-dependent)
Cushingoid appearance (excess alcohol consumption-pseudo-Cushings)
Impaired glucose tolerance (especially ectopic ACTH syndrome)
Hypokalaemia (common with ectopic ACTH secretion), HT
Thin skin
Proximal myopathy
Frontal balding in women
Conjunctival oedema
Osteoporosis
How is Cushings diagnosed?
Diagnosis
Tests-Many to choose from
Dexamethasone overnight suppression test is 1st line, followed by 48hr test.
Failure to suppress=Cushing’s syndrome,
What are the causes of cushings?
Pituitary, adenoma of adrenal, ectopic-thymus, lung, pancreas, pseudo-alcohol and depression, steroid medication
How can you differentiate between a pituitary, adrenal or ectopic cause of Cushings?
ACTH test- pituitary less than 300, ectopic more than 300, adrenal less than 1. In high dose dexam suppression pituitary will be suppressed by 50%, not seen in adrenal/ectopic
What is the treatment for Cushings?
Pituitary-hypophysectomy and radiotherapy, adrenal-adrenalectomy, ectopic-remove source or bilateral adrenalectomy. Also Metyrapone, ketoconazole and fluconazole to decrease cortisol pre-op
What toxicity can occur from keotconazole?
Hepatoxicity
What are the hormonal effects of pan hypopituitarism?
Anterior pituitary-GH:growth failure, TSH-hypothyroidism, LH/FSH-hypogonadism, ACTH-hypoadrenal, Prolactin-none known
What are some causes of hypopituitarism?
Pituitary tumours, secondary metastatic lesions (lung, breast), local brain tumours-(astrocytoma, meningioma, glioma), granulomatous disease, vascular disease, trauma, hypothalamic diseases (syphiilis, meningitis), iatrogenic-surgery, AI-Sheenan:post pregnancy, infection
What are some features of hypopituitarism?
Menstrual irregularities Infertility Impotence Gynaecomastia Abdominal obesity Loss facial hair, loss axillary &pubic hair (M&F) Dry skin and hair Hypothyroid faces Growth retardation
How are the adrenal glands stress response tested?
Synacthen test-ACTH stimulation
What is the treatment for hypopituitarism?
Hormone replacement therapy- thyroxine, hydrocortisone, ADH, GH, sex steroids
What are the effects of giving GH to adults?
Improves well being and QOL, decreased abdo fat, increases muscle mass, strength, exercise capacity and stamina, improves cardiac function, decreased cholesterol and increases LDL, increases bone density, given by daily SC injection
What are the risks of testosterone replacement?
Prostate enlargement, polycythaemia, hepatitis (Only oral tabs)
What are some causes of cranial Diabetes Insipidus?
Familial -isolated in most cases, can be part of DIDMOAD(DI, DM, optic atrophy, deaf). Acquired-idiopathic 50%, trauma-road accidents etc. Rare -tumour, sarcoid, irradiation, meningitis
How do you diagnosis DI?
Water deprivation test
How do you treat DI?
Desmopressin-spray, oral, sublingual, injection
What is the peripheral hormone of ACTH?
Cortisol
What is the peripheral hormone of TSH?
Thyroxine
What is the peripheral hormone of LH/FSH?
Testosterone or Estradiol
What is the peripheral hormone of GH?
IGF-1
What is the peripheral hormone of Prolactin?
No peripheral hormone
How are pituitary tumours sized?
More than or equal to 1cm: Macroadenoma. Less than 1cm: Microadenoma
What can a Non-functioning pituitary adenoma cause compression on?
Optic chiasma, as well as other structures e.g. CN 3,4,6
What can a Non-functioning pituitary adenoma cause?
Hypoadrenalism, hypothyroidism, hypogonadism, DI, GH deficiency
What are some of the physiological causes of raised prolactin?
Breast feeding, pregnancy, stress, sleep
What are some drug causes of raised prolactin?
Dopamine antagonists e.g. metoclopramide, antipsychotics e.g. phenothiazines, antidepressants e.g. TCA, SSRIs, others-estrogens, cocaine