Hyperparathyroidism Flashcards
What is hyperparathyroidism?
overproduction of PTH
What happens if there are high levels of Ca2+ in blood to PTH?
decrease PTH level
What happens in primary hyperparathyroidism?
makes PTH independent of calcium level –hypercalcaemia and hypophosphatemia (Parathyroid adenoma)
What happens in secondary hypoparathyroidism?
makes excess PTH in response to chronic hypocalcaemia and hyperphospahtaemia and low Vit D
What happens in tertiary hyperparathyroidism?
- secondary for a long time and hypercalcaemia – check if kidney transplant
- same symptoms as primary and high phosphate levels
What are the causes for primary hyperparathyroidism?
- Solitary adenoma
- Hyperplasia of all glands
- Parathyroid cancer (rare)
- sometimes Hx of osteoporosis and osteomalacia
What are the RF for primary hyperparathyroidism?
- Female sex
- Age >50-60years
- Family history of PHPT
- MEN 1, 2A or 4
- Current or historical lithium treatment
- Hyperparathyroidism-jaw tumour syndrome
- Hypertension
What are the causes of secondary hyperparathyroidism?
- Low Vit D intake
- Chronic renal failure
- Increased Age is RF
- Liver disease
Why might you have low vit D in secondary hyperparathyroidism?
- malabsoprtion e.g. IBD
- sunlight exposure
- genetic conditions
- medications
What happens anatomically in tertiary hyperparathyroidism?
- longed secondary hyperparathyroidism
- causing glands to act autonomously having undergone hyperplastic or adenomatous change
- this causes high calcium from very high secretion of PTH unlimited by feedback control
When is tertiary hyperparathyroidism usually seen?
chronic renal failure
What is malignant hyperparathyroidism?
parathyroid related protein (PTHrP) is produced by some squamous cell lung cancer breast and renal cell carcinoma
What are PTH levels like in malignant hyperparathyroidism?
- mimics PTH
- high calcium
- PTH is low
What are the symptoms and signs of primary hyperparathyroidism?
- Asymptomatic
- Weak
- Tired
- Depressed
- Thirsty
- Pain, fractures
- High BP
- Bones, groans, abdominal moans
What are the symptoms and signs of secondary hyperparathyroidism?
- Muscle cramps and bone pain
- Renal osteodystrophy
- Calcification in blood vessel and soft tissues
- Fractures/bone pain
- Proximal myopathy
- Fatigue
- Hypocalcaemia:
”CATs go numb”
What are some DDx of primary hyperparathyroidism?
- Familial hypocalciuric hypercalaemia (FHH)
- Humoral hypercalcaemia of malignancy
- Multiple myeloma
- Milk-alkali syndrome
- Sarcoidosis
- Hypervitaminosis D
- Thyrotoxicosis
- Chronic or acute leukaemia
- Immobilisation
- Thiazide use
What are some DDx of secondary hyperparathyroidism?
primary hyperparathyroidism
What are complications of primary hyperparathyroidism?
- Neck haematoma following surgery
- Recurrent and superior laryngeal nerve injury following surgery
- Hypocalcaemia following surgery
- Pneumothorax following surgery
- Osteoporosis
- Bone fractures
- Nephrolithaisis
- Hypoparathyroidism
What are the complications of secondary hyperparathyroidism?
- Renal osteodystrophy
- Osteoporosis
- Calciphylaxis
What investigations are done for primary hyperparathyroidism and the levels?
- Serum calcium: high
- Serum PTH: high (or inapparopirately normal e.g. lithium, thiazide)
- Low PO43- (unless renal failure)
- High ALP
- 24 hour urinary calcium: high
What investigations are done for secondary hyperparathyroidism and what are the levels?
- Serum calcium: low
- PTH: high
- Serum creatinine
- Serum urea
- Low phosphate if Vit D def or high phopahte if CKD
- ALP High
What investigations are done for tertiary hyperparathyroidism and the levels?
- Serum calcium: high
2. PTH: very high
How do you manage mild primary hyperparathyroidism?
- High fluid intake to prevent stones
- Avoid thiazides
- Vit D supplement
- Monitor
How do you manage severe primary hyperparathyroidism?
parathyroidectomy
How do you manage secondary hyperparathyroidism?
- Treat cause
- Phosphate binder / dietary phosphate restriction
- Vit D
- Cinacalcet if PTH >85pmol/L
- UV radiation exposure
What is the prognosis of primary hyperprarthyroidism?
- 8% recurrence in 10yrs
- parathyroidectomy: 95-97% cured
- observation over 10 years 25% end up needing parathyroidectomy
What are the hormones that increase calcium?
- PTH
2. Calcitriol (activated Vit D) (1,25-(OH)2D3)
What hormones are involved in synthesis?
- PTH (parathyroid glands)
- Calcitonin (parafollicular cells)
- Calcitrol (skin and UV light)
What are extracellular Ca2+ levels sensed by?
parathyroid cell
If clacium is low what should PTH do?
PTH should be released
What hormones decrease calcium?
calcitonin
What can calcitonin be used as?
a tumour marker in medullary thyroid cancer
What is calcium metabolism?
- Vitamin D from diet and IV
- Gets formed into (25-OH)D3 by 25-hydroxylase in liver
- This with PTH and 1 alpha hydroxylase is used to form calcitriol in the kidneys
What does increased PTH do to the kidneys?
- 1 alpha hydroxylase stimulation
- Increased calcium reabsorption
- Increase phosphate excretion
What does increased PTH do to the bones?
Increased bone absorption
What does increased PTH do to the small intestine?
- Increased calcium absorption
2. Increased phosphate absorption
What is the overall effect of increased PTH?
- Increase calcium
2. V decreased phosphate
What does calcitriol do to the kidneys?
- increased calcium reabsorption
2. Decrease phosphate reabsorption
What does increased calcitrol do to the bones?
- Increased bone formation
What does increased calcitrol do to the small intestine?
- Increased calcium absorption
2. Increase phosphate absorption
What is the overall result of increased calcitriol?
- V increase in calcium
2. Increase in phosphate
What are blood levels in primary hyperPTH?
- High calcium
2. Low phosphate
What is secondary hyperPTH also known as?
osteomalacia
What are blood levels of secondary hyperPTH?
- Low calcium
- Low phosphate (if vit D def)
- High Phosphate (if CKD)
What are blood levels in tertiary hyperPTH?
- High calcium
2. High phosphate
What are the causes of high calcium when PTH is high?
- Primary hyperPTH
2. Tertiary hyperPTH
What are causes of high calcium when PTH is low?
- Malignancy (bone mtases, multiple myeloma, paraneoplastic (lung)
- Sarcoidosis
- Thiazide diuretics
Hypercalcaemia can also cause pancreatitis
What are causes of low calcium when PTH is high?
Secondary HyperPTH (Osteomalacia)
What are causes of low calcium when PTH is low?
- Surgical complications (iatrogenic)
2. Auto-immune hypoparathyroidism
Whhat is Trousseau’s sign?
inflation of cuff to high BP causes contraction of wrist and fingers
What is Chvostek’s sign?
tapping facial nerve causes twitch of muscle fibres
What are signs of secondary hyperPTH is children?
- Bowed legs
* Knock knees
What are endocrine causes of proximal myopathy?
- Cushing’s
- Osteomalacia
- Thyrotoxicosis
What would XR findings be in primary hyperPTH?
- Subperiosteal bone resorption (radial aspects)
- Acro-osteolysis
- Pepper-pot skull
What would XR findings be in secondary HyperPTH?
- Rachitic rosary of CXR (nodularity at costochondral junctions)
- Looser’s pseudofractures
What is the Mx of acute hypercalcaemia in primary HyperPTH?
- IV fluids
* Bisphosphonates (if calcium remains high)
What is the 1st line management for primary hyperPTH?
total parathyroidectomy – risk of recurrent laryngeal nerve damage
What is the medical treatment of primary hyperPTH?
- Medical (if unsuitable for surgery)
- Cinacalcet
- (drug class: calcimemetic)
How do you treat acute hypocalcaemia in osteomalacia?
IV calcium infusion
(calcium gluconate) – also used in hyperK+
How do you treat osteomalacia medically?
- Calcium
- Vitamin D (inactive –
- ergocalciferol)
How do you treat osteomalacia medically due to CKD?
- Calcium
- Vitamin D (active - alfacalcidol)
- Treat CKD
