Diagnostic Endocrine Disorders Flashcards
To investigate thyroid marker of choice is?
TSH
FT3 is used to diagnose?
Hyperthyroidism, monitor therapy for carbimazole PTU and radioactive iodine
Signs of hyperthyroidism?
Agitation, fine tremor, warm moist skin, palmar erythema, muscle wasting, pruritis, gynaecomastia, sinus tachycardia, atrial fibrillation
Extrathyroid manifestations of graves that are rare?
Thyroid acropachy (digital clubbing and swelling of fingers and toes)
Thyroid dermopathy
Difference between toxic multinodular goitre and subacute thyroiditis?
Non tender thyroid nodules in toxic multinodular goitre and tender firm enlargement in subacute thyroiditis
Assessments in hyperthyroidism?
TRAbs (TSH receptor antibodies) if graves accepted or pregnant
Inflammatory markers such as CRP if thyroidits
TPOAbs (thyroid peroxidase antibodies), if postpartum thyroiditis suspected
FBC and LFT, if about to start anti thyroid drugs
Ultrasound
What can affect thyroid axis?
Age: mild TSH elevation
Pregnancy: TSH suppression late first trimester
Drugs: TSH suppression with dopamine, high dose glucocorticoids, amphetamines bromocriptine amiadorone
Excessive exogenous levothyroxine can cause?
Thyrotoxicosis not hyperthyroidism
A change in ft4 can result in tsh results changing by?
> 100 fold
What happens in sick euthyroid?
Body switches off hpa axis
During starvation what happens to thyroid levels?
Less conversion of t4 to t3
Cortisol mimics action of?
Aldosterone
Hence greater reabsorption na and water
Hypertension
Loss of k and h (increased HCO3-)
Causes of cushings?
Pituitary adenoma, ectoping acth secreting tumour
Adenoma, adrenocorticol rest tumour (islands of adrenal tissue that remian within gonads during development), nodular adrenal hyperplasia
Diagnotic tests for cushings?
- Identify spontaneous hypercortisolism, mild vs pseudo
- Determine whether acth dependent or independent
- Where is acth coming from
Discriminatory signs of cushings?
Easy bruising, facial plethora (swelling), proximal myopathy (weakness), striae, weight gain in children and reduced growth velocity
Tests for cortisol?
24 urine free cortisol, because 2%is free.
If 4x upper limit of normal
Dexamethasone suppression 1mg, cortisol suppressed less than 40 rule out cushings
Late night salivary cortisol:
What happens in lactic alkalosis?
Alkalosis switches on phosphofructokinase which will double lactate production
Metyrapone test?
Decreases serum cortisol, causing increase in 11-deoxycortisol
Low cortisol can cause tanning because?
Pro-opio melanocortin causes MSH melanocyte stimulating hormone and acTH, beta endrophin and lipotropin
Because low cortisol causes high ACTH which causes pro-opio melanocortin
In sick thyroid what happens to hormones?
Low TSH low T4 and T3
In late first semester what happens to TSH?
Low
Difference between primary and secondary adrenal insufficiency?
In primary lack of aldosterone but high ACTH, secondary normal aldosterone but low ACTH
Test for adrenal insufficiency?
Short synacthen test
250 micro gram or IV synthetic ACTH
Take bloods at 0 mins and 60 mins
Normal results is a rise of cortisol over 550 nmol/l
High IGF1 may be seen in?
Pregnancy and puberty, acromegaly
What to look for acromegaly?
High Igf1
High glucose suppresses?
Growth hormone
To check for diabetes what test?
Water deprivation test then desmopressin- cranial diabetes
Superior vena cava obstruction symptoms SVCO?
Chest pain Cough Dysphagia Pleural effusion Strider Oedema Cyanosis
What can cause SVCO?
Lung cancer
Metastatic disease
Lymphoma
How to test for acromegaly?
Oral glucose tolerance test 75g oral glucose then fasting
Take GH and glucose
GH less than 0.4 micro gram/l is a pass
In acromegaly over 5 micro gram
