Endocrine/Metabolic Flashcards
T score values for osteoporosis?
5 answers
-1 and over = normal
-1 to -2.5 = osteopenia
-2.5 or lower = osteoporosis
if aged >50 + Min.Trauma# (not vertebra or hip) + T score <-1.5 then = osteoporosis
If age >50 and min.trauma# at vertebra or hip = osteoporosis
Pros/Cons of bisphosphonates
Pros
Low Cost,
Oral Dose,
Longer half life (so can be stopped and still have effect)
Cons
GI upset
absorption affected by food
Can’t be used in severe CKD
Short lasting myalgia
Denusomab dose?
Denosumab 60mg SubCut 6 monthly
Pros/Cons of Denusomab?
3 pros and 5 cons
Pros
Avoids GI upset
No renal adjustment
6 Monthly
Cons
STRICTLY 6 monthly
Therapy is indefinite
Withdrawal > 4 weeks can lead to spontaneous vertebral fractures
MAY cause hypocalcemia with CKD
Osteonecrosis of the jaw
When do you stop bisphosphonate therapy
5 years after oral versions
-continue for 10 years however in those at high risk of MT#
3 years after IV bisphosphonate
- continue for 6 if high MT# risk
When do you start assessing for osteoporosis?
And when do you start scanning (rebatable)?
Assess women > 45 and men > 55
For MT# or other conditions that effect BMD
Scan when
If W>45 or M>50 has a Minimal trauma fracture then scan
If W> 45 or M> 50 with any of the following: RA, premature menopause, hypogonadism, hyperthyrodism, hyperparathyroidsim, CKD, coeliac/malabsorption, taking glucocorticoids (>3 months dosed over 7.5mg), anti androgen therapy, then also scan and qualify for rebate.
If M or W over 70 years old then scan (DXA)
What are the TSH targets in thyroxine replacement?
< 60 years old TSH target is between 0.5-2.5 milliunits/L
Between 60-80 years old TSH target is 1-5 milliunits/L
Over 80 years old TSG target is 4-6 milliunits/L
General advice to give patients taking thyroxine replacement?
4 answers
- To take thyroxine on an empty stomach, 30-60 minutes before breakfast OR 3 hours after evening meal
- To avoid taking it with supplements that reduce absorption: iron, calcium
- Patient will need long term bloods done to allow for dose titration
- Warn of symptoms of hyperthyroidism as this indicates a dose reduction may be needed
Simple Steps to investigate Hyperthyroidism?
- TSH
- Symptomatic treatment with betablocker
- Retest TSH in 6-8 weeks
- If still hyperthyroid test for TSH-R
- Refer
- Treat
Treatment for severe symptoms of PRIMARY hyperthyroidism
list 3 symptoms
Give 1 example of dosing instructions
Symptoms include weight loss, AF, myopathy, heart failure
Carbimazole 30-45mg, orally, daily but divided into two or three doses.
Review with bloods and adjust every 4-6 weeks
or
propylthiouracil 300-450mg daily in 2-3 divided doses. Also adjust 4-6 weekly
Treatment for milder symptoms in PRIMARY hyperthyroidism?
Carbimazole 10-20mg, orally, daily in 2-3 divided doses. Adjust 4-6 weekly
PTU 100-200mg PO daily in 2-3 divided doses. Adjust 4-6 weekly
After remission of thyrotoxicosis with hyperthyroidism, what is the recommended follow up?
testing should be done every 3-4 months for the first year then annually for 5 years.
(If lifelong antithyroid medication is needed, 3-4 monthly testing is needed initially then 6 monthly thereafter)
During a thyroid storm, what are the management priorities and what may you use to address these ?
5 answers
- stopping thyroid hormone synthesis (with carbimazole)
- decreasing t4–>t3 conversion (with IV dexamethasone)
- Restoring hydration (IV fluids)
- Controlling tachycardia (beta blocker)
- Sedation if needed
What to check for on examination of a Goitre?
4 answers
- Size/shape and consistency of the goitre
- Presence and amount of nodules
- Enlarged lymph nodes
- Pemberton’s sign
If there is a Goitre with a Low TSH, which Imaging should be considered?
Radionucleotide scan and U/S. irrespective of remaining serology.
What are signs and symptoms of Hereditary Haemochromatosis?
(7)
- Loss of libido
- Joint Aches
- Abdominal pain
- Weight loss
- Tiredness/lethargy
- Polyuria, polydipsia
- Chest pain, SOB, palpitations
Name three pieces of advise with regards to management of HH?
- Will require therapeutic venesections if iron overloaded
- Will require regular Iron studies. Depends on ferritin level how often this is.
- Will need a specialist referral if ferritin is over 1000ul/L
- If found to have haemochromatosis, should offer to test family members
What tests should you order for an INCIDENTAL adrenal lesion?
1mg overnight dexamethasone suppression test
Aldosterone: Renin ratio
Plasma metanephrines
(Non Contrast Adrenal CT, if for some reason lesion found on a CTPA)
Signs and Symptoms of pheochromacytoma?
Flushing
Sweating
Palpitations
Sense of doom
Tremor
Headache
Anxiety
Constipation
Weight loss
Common causes of HYPOphoshpataemia ?
4 broad groups
- Redistribution form extracellular fluid to intracellular.
(glucose IV infusions, diabetic ketoacidosis, acute respiratory alkalosis, refeeding syndrome) - Poor intestinal absorption
usually from phosphate binders. E.g. antacids. - Increased kidney excretion
(primary hyperparathyroid, PTH related protein dependent hypercalcaemia of malignancy, Intrinsic renal disease -Fanconi syndrome, Drugs: alcohol, heavy metals) - Extra-renal removal
Haemodialysis. - Also from IV iron transfusion with carboxymaltose
- Alcoholism via multiple mechanisms: poor intake, increased GIT losses, magnesium depletion.
Why does an iron infusion cause low phosphate?
Which formulation is worst?
Occurs mainly with iron carboxymaltose.
There is inhibition of a fibroblast growth factor- a hormone that regulates phosphate metabolism, and is produced by osteoblasts/casts.
Inhibition of it reduced PCT reabsorption.
Somehow iron infusions also inhibit 1-a-hydrolyase –> low vitamin D and then low intestinal absorption of phosphate
What investigations to order for hypophospatemia?
(5)
- fractional excretion of phosphate (Figure 1)
- parathyroid hormone
- serum corrected calcium
- 1,25-dihydroxyvitamin D3
- 25-hydroxyvitamin D.
What does phosphate do in the body?
What are the symptoms of LOW phosphate?
Plays a key role in energy storage, metabolism and signalling within the cell through phosphorylation.
So it ends up affected multiple organ systems:
mild irritability, paraesthesia and muscle weakness, to more severe manifestations such as haemolytic anaemia, severe infection, delirium, generalised seizures, cardiac arrythmias, cardiomyopathy, respiratory failure and coma.
Replacement of phosphate can occur simply by oral replacement if levels > 0.3.
If severe <0.3 then IV replacement should be used,
What are the things to watch for with IV phosphate replacement?
- Hypocalcemia and the resultant cardiac arrhythmia that could occur.
- Kidney injury - heterotopic calcification - bone growing where it shouldn’t! like in the kidney!
- Vitamin D deficiency- replace as needed as this can help with phosphate levels. Can have cholecalciferol or calcitriol.
What are the causes for HYPERcalcemia?
What is the main cause?
- the main cause is hyperparathyroidism
- Cancer (from PTHrP related cancers)
- Medications
- Taking too much calcium in supplements
- Too much vitamin D
- Hyperthyroidism
What is the process of investigation once you find a raised Calcium?
Usually start by checking serum albumin or serum ionised calcium
Next is PTH
If that is high well.. you have an answer
If PTH is Low, test PTH-related protein in the plasma (PTHrP)
–> if PTH related protein high then indicates cancers like Renal carcinomas, leukemias, lymphomas, and rhabdomyosarcoma.
–> if PTHrP is low then test for Vitamin D (see flow chart)
Primary hyperparathyroidism is usually caused by a single parathyroid adenoma.
When is non-surgical, expectant management appropriate?
In patients aged 50 and older a watch and wait approach can be appropriate IF all the following are met:
- serum calcium corrected for albumin remains lower than 2.9
- There is normal renal function
- there is no nephrolithiasis or nephrocalcinosis
- BMD higher than -2.5
- no symptoms
Monitor every 6-12 months with serum calcium and renal function
BMD every 2 years
What should people with primary hyperparathyroidism be doing / not doing?
(3)
- avoid high calcium intake (from diet or supps)
- limit vitamin D intake as this can cause increased calcium levels . no more than the normal 1000IU/day
- Drink plenty of water- high water intake of 2.5 L a day, unless contraindicated for other reasons
What does a high PTH do to calcium and phosphate?
Increases Calcium resorption from bone
This also increases phosphate resorption from bone
PTH will increase Calcium reabsorption from the kidneys BUT
promotes Phosphate excretion
hence this can all lead to hypercalcemia and hypophosphatemia
What are the three clinical types of hyponatramia worth classifying into?
Hypovolemic- usually due to GI losses
Euvolemic- SIADH, medications, hypothyroidism, primary polydipsia
Hypervolemic - usually cardiac or renal, maybe liver failure