Endocrine Flashcards
How is Grave’s diagnosed? What would you expect to be the TSH and T3 / T4 levels?
TSH antibodies (activate the TSH receptor)
TSH very low (inhibited by high T3 and T4 levels)
T3 / T4 high
What test is used to diagnose Cushing’s disease?
Dexamethasone suppression test
tests for adrenal hyperactivity
Why is phosphate low in primary hyperparathyroidism but high in tertiary hyperparathyroidism? What is the difference between 1/2/3 forms?
Primary: Parathyroid overactive e.g. due to tumour
Secondary: Parathyroid overactive due to low Vit D or calcium levels.
Tertiary: Long term secondary results in hyperplasia of parathyroid glands.
PTH causes increased calcium/Phos absorption in intestines, increased resporption from bone and increased reabsorption of calcium but excretion of phosphate in the kidneys.
In primary, the PTH is moderately raised, so more Phosphate is excreted than absorbed/resorbed.
In tertiary, PTH is so high, that too much phosphate is absorbed/resorbed to be excreted.
Where is calcidiol converted into the active form of Vit D?
7-dehydrocholesterol –> cholecalciferol (D3) [Skin]
- -> Calcidiol (25(OH) [Liver]
- -> Calcitriol (1,25(OH2) [Kidney] “Active form”
What are the abnormal levels for blood sugar for fasting and random blood glucose?
Normal Fasting: 5.6 - 7.0
Normal Random: 7.8 - 11.0
True or false, type 2 diabetes has a stronger genetic component than Type 1?
True
Give two symptoms of diabetes
Polyuria Polydipsia Weight loss Fatigue Blurred vision
What is the pathophysiology of diabetes insipidus?
What is the difference between cranial and nephrogenic DI?
Cranial DI: Reduced ADH production resulting in excessive urination (>3L/day)
Nephrogenic DI: Reduced renal sensitivity to ADH resulting in excessive urination (>3L/day)
Give two complications of diabetes?
Nephropathy
Neuropathy
Retinopathy
CVD
How is diabetes insipidus treated?
Desmopressin (ADH analogue)
Treat cause e.g. pituitary tumour
How is diabetes insipidus diagnosed?
Water deprivation test + measure urine output
+ Desmopressin to see if cranial/nephrogenic.
[Monitor U&E + serum/urine osmolality]
Which is more common cranial or nephrogenic diabetes insipidus?
Cranial (ADH production is reduced)
[vs. nephrogenic where there is renal insensitivity to ADH]
What is cushing’s disease?
Raised glucocorticoids (cortisol) driven by increased adrenocorticotropic hormone production (ACTH)
Give two signs of cushing’s disease
Buffalo hump Moon face Weight gain Mood changes Hypertension Raised plasma cortisol
What is addison’s disease?
Adrenal insufficiency (hypoadrenalism)
- Low cortisol
- Low aldosterone
Primary = adrenal gland failure Secondary = low ACTH or CRH
Does Addison’s disease cause hypo or hyperkalaemia?
Addison’s produces hyperkalaemia and hyponatraemia.
This is due to low aldosterone levels.
True or false, ACEi are known to produce hyperkalaemia?
True. By inhibiting aldosterone production, more sodium is wasted in urine and more potassium is absorbed.
What is thyrotoxicosis and myxoedema?
Thyrotoxicosis = Hypothyroidism Myxoedema = Hyperthyroidism
Give three signs/symptoms of hyperthyroidism?
Weight loss Heat intolerance Palpitations irritability Hair thinning Goitre Tachycardia
True or false, hyperthyroidism is more common in women?
True. 5x more common.
What is the most common form of hyperthyroidism?
Grave’s disease (60-80% of cases)
Give three signs/symptoms of hypothyroidism
Fatigue Cold intolerance Weight gain Constipation Bradycardia Dry hair Cold hands Puffy face
What medical treatment is given to patients with hyperthyroidism?
Carbimzole
Proplythiouracil
Beta blocker
What causes SIADH? What lab inverstigations would confirm SIADH?
Excessive ADH production causes blood volume increase and raised BP, which in turn switches off the RAS system, decreases Aldosterone so sodium gets wasted into the urine.
Low plasma osmolality
High urine osmolality
What causes acromegaly?
Hypersecretion of growth hormone by pituitary gland
Give two signs of acromegaly
Acral enlargement (large periperhies) Hyperhidrosis Arthralgia Headaches Macroglossia
What is the diagnostic test for acromegaly?
Glucose tolerance test
Glucose inhibits growth hormone
What is the treatment for acromegaly?
Transsphenoidal pituitary surgery Somatostatin analogues (inhibit Growth hormone)
Give two common complications associated with acromegaly
Diabetes
CVD
Osteoporosis
Heart failure
What is Conn’s syndrome?
Hyperaldosteronism (Mostly due to adenoma)
Results in increased plasma Na + Hypokalaemia + water retention (increased BP)
Give two signs of hypercalcaemia
Bones - Bone pain
Stones - Kidney stones
Groans - Abdominal pain, N&V, constipation.
Moans - Depression, Psychosis.
In hyperkalaemia, what medication is given as the 1st line to reduce the risk to the heart?
Calcium gluconate
Cardio protective
