Cushings and Hypopituitarism Flashcards by Gillian Miller

Screening Tests for Cushings

Definitive Tests for Cushings

Screening:
-1mg dexamethasone suppression test
-Urine free cortisol test (<250 is normal)
-Diurnal cortisol variation
Definitive:
2 day 2mg/day dexamethasone

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Aetiology of Cushings

Pituitary (80% plus)
Adenoma of adrenal
Benign
cancer
Ectopic
Thymus
Lung
Pancreas
Pseudo
Alcohol and Depression
Steroid medication

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When treatng cushings, what would you do if hypophysectomy did not work?

External radiotherapy

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How would you treat ectopic cushings?

Bilateral adrenalectomy if you cannot find source etc

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Drug treatment for cushings if other treatment does not work

Metyrapone- if other treatments fail - while waiting for radiotherapy to work- S/E common
Ketoconazole
Pasireotide- new somatostatin analogue

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Autoimmune causes of hypopituitarism

Sheehans

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Secondary metastatic lesions that could cause hypopituitarism

Breast, lung

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Local brain tumours

Astrocytoma
Meningioma
Glioma

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Granulomatous diseases that could cause hypopituitarism

TB
Sarcoidosis
Histiocytosis X

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Vascular disease that could cause hypopituitarism

Polyarteritis

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Hypothalamic diseases that could cause hypopituitarism

Syphilis

Meningites

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Causes of hypopituitarism

Pituitary Tumours
Secondary metastatic lesions
lung, breast
Local brain tumours
Astrocytoma, meningioma, glioma
Granulomatous diseases
TB, Histiocytosis X, sarcoidosis
Vascular diseases
Polyarteritis
Trauma
road accidents, skull fractures
Hypothalamic diseases
Syphilis, meningitis
Iatrogenic; surgery
Autoimmune;Sheehan – post pregnancy
Infection; meningitis

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Signs and symptoms of anterior hypopituitarism

Menstrual irregularities (F)
Infertility, impotence
Gynaecomastia (M) (testosterone deficiency)
Abdominal obesity
Loss of facial hair (M)
Loss of axillary and pubic hair (M&F)
Dry skin and hair
Hypothyroid faces
growth retardation (children)

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Testing for Hypopituitarism

Baseline pituitary function tests

fT4, TSH
Oestradiol/Testosterone, LH FSH
GH, IGF-1
Prolactin

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Replacement therapy for hypopituitarism

Thyroxine		 100-150mcg/day
Hydrocortisone 10-25 mg/day (am/pm)
ADH			 Desmospray (nasal) or tablets
GH			 GH nightly sc
Sex Steroids	 Oest/prog pill for F, Testosterone for males

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Growth hormone and bone density?

GH increases bone density

Growth hormone and muscle mass?

GH increases muscle mass, strength, exercise capacity and stamina

GH and abdominal obesity

GH decreases abdominal obesity

GH and cardiac function

GH improves cardiac function

GH and cholesterol and LDL

Decreases cholesterol and LDL

How is GH administered?

Daily by subcutaneous injection

Testosterone replacement

IM injection every 3-4 weeks (sustanon)
Skin gel (testogel, tostram)
Prolonged IM injection 10-14 wks (nebido)
(Oral tablets (restandol))

Intramuscular injection that can be given as testosterone replacement?

Sustanon

-Given every 3-4 weeks

Restandol is an oral testosterone replacement. What are the risks of tablet oral testosterone?

Hepatitis

Risks of Testosterone Replacement

Prostate Enlargement. Does NOT cause prostate cancer but may make it grow - monitor PR exam and PSA Polycythaemia - monitor FBC Hepatitis (only for oral tablets) - monitor LFTs

Causes of Cranial Diabetes Insipidus

``` Familial isolated in most cases DIDMOAD (DI, DM, optic atrophy, deaf) Acquired Idiopathic in 50% Trauma; road accidents, surgery, skull fracture RARE Tumour, sarcoid, ext irradiation, meningitis ```

Most common type of pituitary gland tumour

Prolactinoma

Symptoms of a prolactinoma

Headaches or reduced vision if prolactinoma is pressing on brain or nerves nearby Irregular periods or no periods. Reduced fertility. Reduced sex drive. Milk leaking from the breasts (known as galactorrhoea). The milk may leak out by itself, or may only show when the breast is squeezed. (Note: leakage of milk from the breasts is normal towards the end of pregnancy, with recent childbirth, if breast-feeding, and for some time after finishing breast-feeding.) Increased growth of hair on the face or body. MEN may have: Reduced fertility. Erectile dysfunction (difficulty having an erection). Reduced sex drive (libido). Breast enlargement (called gynaecomastia). Very rarely, leakage of milk from the breasts.

Normal levels of prolactin

5000mU/L

Drugs that can increase prolactin levels

Risperidone, clopramide, domperidone

Somatostatin and GH

Somatostatin analogues are currently used as treatment for GH acromegaly, they may also be used to shrink large tumours before surgery. They are synthetic analogues of somatostatin which inhibits GH production -Injected every 2-4 weeks for effective treatment

What type of receptor does TSH bind to?

Surface receptors This then activates G proteins and conversion of GTP to GDP and production of cAMP cAMP increases production and release of T3 and T4 T3 and T4 circulate in bound and free forms On release T3 and T4 bind to receptor in target cells. Complex translocates to the nucleus Binds to Thyroid Response Elements on target genes Stimulates transcription of these genes Increase BMR

Struma ovarri

"goitre of the ovary" | Contains thyroid tissue

Can you get a TSH secreting adenoma?

Yes, but rare

Causes of hyperthyroidism

Symptoms and signs occur as a result of excess T3 and T4 85% are due to Grave’s disease Other causes include hyperfunctioning nodules/tumours and thyroiditis TSH secreting pituitary adenoma (rare) Ectopic production (struma ovarii) Factitious (exogenous intake)

DeQuervains Thyroiditis

De Quervains Thyroiditis: hyperthyroid then hypothyroid, euthyroid. Patients may suffer dysphagia. There are multi-nucleated giant cells on histology

Difference between thyroiditis and Graves disease in radionucleotide isotope uptake?

Thyroiditis = decreased uptake | Graves disease = increased uptake