Endocrinology Flashcards
Define acromegaly.
Constellation of signs and symptoms caused by hypersecretion of GH in adults.
What does excess GH causes in children pre-puberty?
o Gigantism
What are the presenting symptoms of acromegaly?
o Very gradual progression of symptoms over many years
o Rings and shoes becoming tight
o Increased sweating
o Headaches
o Carpal tunnel syndrome
o Hypopituitary symptoms = Hypogonadism, Hypothyroidism, Hypoadrenalism
o Visual disturbances (due to compression of optic chiasm by tumour)
o Hyperprolactinaemia = Irregular periods, Decreased libido, Impotence
What are the signs of acromegaly on examination?
o Hands - large spade-like hands with thick greasy skin, carpel tunnel syndrome signs and premature osteoarthritis
o Face - prominent eyebrow ridge, prominent cheeks, broad nose bridge, prominent nasolabial folds, thick lips, increased gap between teeth, large tongue, prognathism, husky resonant voice (due to thickening of vocal cords)
o Visual Field Loss - bitemporal superior quadrantopia progressing to bitemporal hemianopia
o Neck - multinodular goitre
o Feet - enlarged

What are the appropriate investigations for acromegaly?
o Serum IGF-1 - useful screening test (GH stimulates IGF-1 secretion)
o Oral Glucose Tolerance Test (OGTT) - positive result = failure of suppression of GH after 75 g oral glucose load
o Pituitary Function Tests - 9am cortisol, free T4 and TSH, LH and FSH, testosterone, prolactin
o MRI of Brain - visualise the pituitary adenoma
What is the treatment of acromegaly?
o Surgical = trans-sphenoidal hypophysectomy
o Radiotherapy = adjunctive to surgery
o Medical = if surgery is contraindicated or refused
- Subcutaneous Somatostatin Analogues - octreotide, lanreotide -> side-effects = abdominal pain, steatorrhoea, glucose intolerance, gallstones
- Oral Dopamine Agonists - bromocriptine, cabergoline -> side-effects = nausea, vomiting, constipation, postural hypotension, psychosis (RARE)
- GH Antagonist (pegvisomant)
- Monitoring GH and IGF1 levels
What are the possible complications of acromegaly?
o CVS = cardiomegaly, hypertension
o Respiratory = obstructive sleep apnoea
o GI = colonic polyps
o Reproductive = hyperprolactinaemia (in 30% of cases)
o Metabolic = hypercalcaemia, hyperphosphataemia, renal stones, DM, hypertriglyceridaemia
o Psychological = depression, psychosis (from dopamine agonists)
What are the possible complications of acromegaly surgery treatment?
Nasoseptal perforation
Hypopituitarism
Adenoma recurrence
CSF leak
Infection
Define carcinoid syndrome.
Constellation of symptoms caused by systemic release of humoral factors from carcinoid tumours.
What are the presenting symptoms of carcinoid syndrome?
o Main symptom = Paroxysmal Flushing
o Diarrhoea
o Crampy abdominal pain
o Wheeze
o Sweating
o Palpitations
What are the signs of carcinoid syndrome on examination?
Facial flushing
Telangiectasia
Wheeze
Right-sided murmurs (tricuspid stenosis/regurgitation or pulmonary stenosis)
Nodular hepatomegaly in cases of metastatic disease
What are the signs of carcinoid crisis on examination?
Profound flushing
Bronchospasm
Tachycardia
Fluctuating blood pressure
What are the appropriate investigations for carcinoid syndrome?
o 24 hours urine collection - check 5-HIAA levels (metabolite of serotonin)
o Blood - plasma chromogranin A and B, fasting gut hormones
o CT or MRI Scan - localise the tumour
o Radioisotope Scan - radiolabelled somatostatin analogue helps localise the tumour
o Investigations for MEN-1
What is MEN-1?
o Multiple Endocrine Neoplasia Type 1 (MEN1)
- a hereditary condition associated with tumors of the endocrine (hormone producing) glands
Define Cushing’s syndrome.
Syndrome associated with chronic inappropriate elevation of free circulating cortisol.
What are the types of Cushing’s syndrome?
o ACTH Dependent (80%)
- excess ACTH from a pituitary adenoma (Cushing’s disease)
- ectopic ACTH (e.g. lung cancer, pulmonary carcinoid tumours)
o ACTH Independent (20%)
- benign adrenal adenoma
- adrenal carcinoma
What are the presenting symptoms of Cushing’s syndrome?
Increasing weight
Fatigue
Muscle weakness
Myalgia
Thin skin
Easy bruising
Poor wound healing
Fractures
Hirsuitism
Acne
Frontal balding
Oligomenorrhoea/amenorrhoea
Depression or psychosis
What are the signs of Cushing’s syndrome on examination?
Moon face
Facial plethora
Interscapular fat pad
Proximal muscle weakness
Thin skin
Bruises
Central obesity
Pink/purple striae on abdomen/breast/thighs
Kyphosis (due to vertebral fracture)
Poorly healing wounds
Hirsuitism, acne, frontal balding
Hypertension
Ankle oedema (due to salt and water retention from the mineralocorticoid effect of cortisol)
Pigmentation in ACTH dependent cases
What are the appropriate investigations for diagnosing Cushing’s disease?
o Must be performed on patients with a high pre-test probability
o Bloods - U&Es (hypokalaemia due to mineralocorticoid effect), glucose
o Initial High-Sensitivity Tests - urinary free cortisol, late-night salivary cortisol, overnight dexamethasone suppression test, low dose dexamethasone suppression test (LDDST) = Give 0.5 mg dexamethasone orally ever 6 hrs for 48 hrs
What are the appropriate investigations for identifying underlying causes of Cushing’s disease?
o ACTH-independent (adrenal adenoma/carcinoma) = low plasma ACTH, CT or MRI of adrenals
o ACTH-dependent (pituitary adenoma) = high plasma ACTH, pituitary MRI, high-dose dexamethasone suppression test, inferior petrosal sinus sampling (SUPERIOR to high-dose dexamethasone suppression test)
o ACTH-dependent (ectopic) = if lung cancer suspected: CXR, sputum cytology, bronchoscopy, CT san
What is the treatment for Cushing’s syndrome?
o If iatrogenic = discontinue steroids, use lower dose or use a steroid-sparing agent
o Medical = inhibit cortisol synthesis with metyrapone or ketoconazole, treat osteoporosis, physiotherapy for muscle weakness
o Surgical = pituitary adenomas - trans-sphenoidal adenoma resection or for adrenal adenoma/carcinoma - surgical removal of tumour
o Radiotherapy = performed in those who are not cured and have persistent high cortisol after trans-sphenoidal resection of the tumour
What are the possible complications of Cushing’s syndrome?
o Of the disease = Diabetes, Osteoporosis, Hypertension, Pre-disposition to infections, Long-term depression even years following treatment starting
o Surgery treatment = CSF leakage, Meningitis, Sphenoid sinusitis, Hypopituitarism
Medicinal treatment = Hypopituitarism, Radionecrosis, Increased risk of second intracranial tumours and stroke
Define diabetes insipidus.
A disorder of inadequate secretion or of insensitivity to vasopressin (ADH) leading to hypotonic polyuria.
o Central DI = failure of ADH secretion by the posterior pituitary
o Nephrogenic DI = insensitivity of the collecting duct to ADH
What are the causes of central diabetes insipidus?
Idiopathic
Tumours (e.g. pituitary tumour)
Infiltrative (e.g. sarcoidosis)
Infection (e.g. meningitis)
Vascular (e.g. aneurysms, Sheehan syndrome)
Trauma (e.g. head injury, neurosurgery)



