Endocrine causes of hypertension Flashcards
What is the function of mineralocorticoids?
Act in the distal tubules and cortical collecting ducts by increasing expression of basolateral Na/K exchange pumpsand apical ENaC channels, this leads to net K loss and Na reabsorption
What are the 3 causes of primary hyperaldosteronism?
Conn’s syndrome, bilateral adrenal hyperplasia, aldosterone producing carcinoma (Rare)
What are the 5 causes of secondary hyperaldosteronism?
- Renal artery stenosis
- Renal hypoperfusion
- Cirrhosis
- Nephrotic syndrome
- Renin secreting tumours
What is AME? What is its treatment?
Apparent mineralocorticoid excess
Congenital absence of 11B-HSD allows cortisol to stimulate the aldosterone receptor and cause severe hypertension in childhood. Liquorice can also inhibit this enzyme.
Dexamethsone suppression of endoegnous ACTH alongside anti-hypertensives
What is Liddle’s syndrome?
Pseudoaldosteronism due to hereditary increased ENaC activity
What is dexamthasone suppressible hyperaldosteronism?
A rare familial condition in which a hybrid gene forms, combining the regulatory region of another gene onto the gene encoding aldosterone synthase.
Which 2 types of tumours can produce catecholamines?
Phaeochromocytomas and paragangliomas
What 4 familial syndromes are associated with catecholamine producing tumours?
- MENIIa/IIb due to RET protoonocgene mutation
- Von-Hippel Lindau syndrome
- Neurofibromatosis
- SDH B, C, D
What investigations should be conducted in a patient suspected of having catecholamine producing tumours?
24 hour urine collection for catecholamines and metadrenalines (if results are borderline suppression tests can be used)
Localisation of the tumour with CT or MRI
Screening for genetic conditions
What is the management of catecholamine producing tumours?
- alpha blockade- phenoxybenzamine starting at 10mg BD titrating up to 20mg QDS
- beta blockade- propranolol 20mg QDS
- Surgery
