Endocrine Flashcards
What disease can lithium cause?
Diabetes insipidus (no ADH)
What are the features of DI?
Hypernatraemia, polyuria, polydipsia
In DKA, is total body K+ high or low?
Low
What is the mode of action of metformin?
Biguanide that activates AMPK which inhibits hepatic glucose production
What are some adverse effects of metformin?
Weight loss, GI intolerance (nausea, diarrhoea)
Why is metformin contraindicated in renal failure?
Lactic acidosis
What are some common causes of DKA?
Medication non-compliance, surgery, infection, inflammatory states, alcohol abuse, poor dosage of insulin, first presentation
What are the 4 principles of Mx of DKA?
- Fluid replacement
2. K+ replacement if
What do you need to take into account when measuring testosterone levels?
- Diurnal variation
- Must repeat if low
- Conditions that affect SHBG may alter TT
What testosterone replacement options are available?
- IM testosterone ester: every 2-3 weeks
- IM testosterone undecanoate: every 3 months
- Testosterone gels: less site irritation
- Testosterone patches: daily, not C/I in bleeding disorders
- S/C testosterone implants: every 6 months
- Oral testosterone: 2-3 times/day
What are the potential A/E of testosterone replacement?
- Prostate cancer, BPH
- Sleep apnoea
- Acne
- Breast cancer
- Reduced fertility
- Gynaecomastia
- Polycythemia
- Mood fluctuations
- Dependent on route
What is the mechanism of action of glibenclamide?
Stimulates beta cell insulin release
Note = sulphonylurea (gliclazide, glipizide, glimepride)
What is the mechanism of action of acarbose? Why is it not well tolerated
Inhibits enzyme that breaks down starches and disaccharides
Flatulence
What is the mechanism of action of glitazones?
Stimulate PPAR-gamma and reverse insulin resistance
Many A/Es: weight gain, fluid retention and CCF, bone fractures, bladder cancer
What is the mechanism of action of GLP-1 analogues?
- Improve pancreatic islet glucose sensing and release
- Slow gastric emptying and improve satiety
What is the mechanism of action of DPP4 inhibitors?
Prolong GLP-1 activity
What is the mechanism of action of SGLT2 inhibitors?
Inhibit main glucose transporter in renal tube
What is the treatment for HHS?
- Fluids
- Monitor urine output and CVP if required
- Insulin
- K+
- Prophylactic heparin
- Look for cause
What is the treatment of a prolactinoma?
- Dopamine agonists
- Transphenoidal hypophysectomy
What tests are be used for diagnosis of acromegaly?
- Increased GH or IGF-1
- Failure to suppress OGTT
- DM or IGT
- MRI/CT pituitary
What is the treatment of acromegaly?
- Transphenoidal hypophysectomy (first line)
- Radiotherapy
- Ocreotide, bromocriptine
What tests are required to diagnose Cushing’s syndrome?
- Urinary 24 hour free cortisol
- Overnight dexamethasone suppression test
- Establish ACTH levels ± imaging for cause
- If ACTH excess, inferior petrosal sinus sampling required
What tests are required to diagnose Addison’s disease?
- Serum cortisol (low)
- Serum ACTH (high)
- Synacthen test
How do you manage an Addisonian crisis?
- Hydrocortisone 100mg IV 6hrly
- Fluid replacement (IV normal saline)
- Glucose if hypoglycaemic
How do you manage Addison’s disease (not crisis)?
Glucocorticoid and mineralocorticoid replacement
What are the symptoms of Addison’s disease?
- Fatigue, lethargy
- Hypotension
- Anorexia, weight loss
- N+V
What is clinical triad in Conn’s syndrome?
Hypertension, hypokalaemia, metabolic alkalosis
What tumours occur in MEN1?
Pituitary, pancreas and parathyroid
When do you check thyroid function in thyroid disease?
6 weeks post-therapy commencement
What TFT results are expected in subclinical hypothyroidism?
TSH elevated by FT4 and FT3 normal
What are some symptoms of androgen deficiency?
- Decreased sense of well being, poor concentration
- Tiredness, poor stamina
- Depression, irritability
- Reduced libido
- Erectile failure (rare)
- Reduced muscle mass and strength
- OP and fracture
- Increased fat mass
- Gynaecomastia
What are contraindications to testosterone replacement therapy?
- Prostate cancer
- Breast cancer
- Erythrocytosis or hyperviscosity
- Untreated OSA
- Severe LUTS
- Class III or IV HF
- Desire to have a child
What needs to be monitored in patients on testosterone replacement therapy?
- History and examination
- TT
- LFTs
- PSA and DRE
- Lipids
- Haematocrit
- BMD
