Endo Flashcards
What is Acromegaly?
A disorder of excessive growth hormone
what is the most common cause of acromegaly?
Pituitary adenoma - 95%
what is gigantism?
excessive GH secretion before epiphyseal closure, during childhood or adolescence leading to increased linear growth
what are 5 rarer causes of acromegaly?
Bronchial carcinoid tumour
Lung carcinoids
Pancreatic islet cell tumour
Phaeochromocytoma
Paraneoplastic syndrome due to ectopic growth hormone releasing hormone (GHRH) or growth hormone (GH) secretion
what 2 hormones inhibit the secretion of GH?
Dopamine
Somatostatin
what is the pathophysiology of acromegaly?
Increased GH => increased glucose release, muscles retain nitrogen causing them to grow => epiphyseal plates fused so can only grow in places where there is still growth => jaw, nose, hands, feet
5 symptoms of acromegaly?
Bigger hands, feet and face
excessive sweating
tiredness
weight gain
headache
deep voice/amenorrhoea
6 signs of acromegaly?
Bi-temporal hemianopia
spade like hands and feet
large tongue - macroglossia
Jaw protrusion - prognathism
interdental seperation
predominant forehead
what are 6 conditions related to acromegaly?
Hypertrophic heart
Hypertension
T2DM
Carpal tunnel syndrome
Colorectal cancer
what is the 1st line investigations for acromegaly?
Raised insulin like growth factor 1
What is the gold standard test for acromegaly to comfirm diagnosis after 1st line testing?
oral glucose tolerance test
- in normal patients GH suppressed to <2 with hyperglycaemia
- no suppression of GH in acromegaly
what scan can be used in acromegaly?
MRI pituitary - ?pituitary tumour
What is the 1st, 2nd and 3rd line management for acromegaly?
1st line - trans-sphenoidal surgery if pituitary adenoma
2nd line -
- Cabergoline (dopamine agonist)
- Somatostatin analogue (octreotide)
- Pegvisomant - GH receptor antagonist give SC OD
3rd line - Radiotherapy,
What are 5 complications of acromegaly?
T2DM
Arthritis and carpal tunnel
Cardiac - cardiomyopathy, heart failure, HTN
Colorectal cancer
Obstructive sleep apneoa
what visual field defect is associated with acromegaly?
Bitemporal hemianopia
what is the inheritance pattern for inherited multiple endocrine neoplasia?
autosomal dominant
what are the 3 different types of multiple endocrine neoplasia?
MEN1
MEN2A
MEN2B
what is the most common presentation of MEN1?
hypercalcaemia
what is the most common cancer associated with multiple endocrine neoplasia 1?
Pituitary adenoma - 60% of MEN1 patients
what is the cause of MEN1?
mutations in MEN1 tumour supressor gene
what is the presentation of multiple endocrine neoplasia (MEN) 1?
3Ps
Primary Hyperparathyroidism
Pancreatic neuroendocrine tumour (50%)
Pituitary Adenoma (70%)
Also adrenal and thyroid cancers
what is Addison’s disease?
Autoimmune destruction of the adrenal glands leading to reduced cortisol and aldosterone production
Most common cause of primary hypoadrenalism in UK
what are 5 causes of secondary adrenal insufficiency?
Underacting pituitary not releasing ACTH
congenital underdevelopment (hypoplasia) of pituitary
Pituitary surgery
infection
loss of blood flow to pituitary - apoplexy
Pituitary radiotherapy
what is the cause of tertiary adrenal insuficiency?
Inadequate CRH release from hypothalamus
Usually due to long term steroid use (>3 weeks) which suppresses hypothalamus