Calcium Disorders Flashcards
What are the common causes of hypercalcaemia?
90% are either:
- Primary Hyperparathyroidism
- Malignant Hypercalcaemia
OTher:
Miscellaneous:
- Thyroidectomy
- Acromegaly
- Adrenal insufficiency
- Parental nutrition
Parathyroid:
- Familial Hypocalciuric Hypercalcaemia (FHH)
- MEN
- Familial hypocalciuric hypercalcemia
- Tertiary hyperparathyroidism
Non-parathyroid:
- Vitamid D intoxication
- Chronic granulomatous infiltration e.g. Sarcoid, TB, histoplasmosis
Meds:
- Drugs e.g. Thiazide diuretic or Lithium
- XS Vitamin A
What causes Primary Hyperparathyroidism?
85% are adenomas
~15% are 4 gland hyperplasia
Very rarely:
- MEN 1 or 2A
- Parathyroid Carcinoma
How does Hypercalcaemia present?
GI - Anorexia, Constipation & N&V
CV - Short QT, Hypertension & Bradycardia
Neuro - Loss of Conc. & confusion
Renal - Polyuria & Polydipsia + Nephrolithiasis
MSK - Muscle Weakness & bone pain
How does Primary Hyperparathyroidism present?
Its generally asymptomatic but can cause symptoms of hypercalcaemia
What is Familial Hypocalciuric Hypercalcaemia?
An autosomal dominant disorder causing Calcium-Sensing Receptor (CaSR) defects
- Low levels of urinary calcium
- PTH is elevated or normal
- No indication of abnormal parathyroid tissue on US.
What tests are appropriate for Hypercalcaemia?
hint theres loads
- Serum Ca, PO4/mg, PTH & Albumin
- Serum ACE (Sarcoid)
- 24 hour urine collection for calcium (low = FHH)
- U&Es
- ALKP
- Lymph node exam (malignancy)
- Myeloma screen (osteolytic metastases)
- ECG (short QT)
- FH
- Med History
Abdo US for kidney stones
Parathyroid US for adedomas etc.
What are the initial tests for hypercalcaemia?
Serum Ca / PO4 / PTH / Albumin
FH & Med history
What are the “levels” of hypercalcaemia?
<3mmol/l - Generally aymptomatic
3-3.5mmol/l -~symptomatic & prompt treatment needed
> 3.5mmol/l - Emergency. Risks Dysrhythmia & coma
How do you treat hypercalcaemia first?
Rehydration & IV bisphosphonates (inhibit osteoclasts)
What can you give hypercalcaemics when bisphosphonates fail/arn’t tolerated?
Calcitonin
What treatments are there for to decrease GI absorption disease causing hypercalcaemia?
Glucocorticoids e.g. Hydrocortisone
How would we treat Primary Hyperparathyroidism Hypercalcaemia?
Parathyroidectomy
OR
Calcimetics e.g. Cinacalcet
Summary of Hypercalcaemia treatments?
1st) Rehydrate and IV bisphosphonates
- Calcitonin
- Cinacalcet
- Parathyroidectomy
- Glucocorticoids
How does PTH differentiate the cause of Hypercalcaemia?
In hypercalcaemia PTH should be low.
If it is then the cause is outside the Parathyroid e.g. malignancy or drugs
If its high then theres some reason PTH is overproduced e.g. FHH, renal failure or Primary hyperparathyroidism
What are the main causes of Hypocalcaemia?
Low PTH aka hypoparathyroidism:
- Neck surgery e.g. thyroidectomy
- Autoimmune
- Infiltration of parathyroid e.g. hemochromatosis
- Radiation
- HIV
High PTH (2nd* Hyperparathyroidism due to hypocalcaemia):
- Renal Disease
- Pseudohypoparathyroidism
- Pancreatitis: FFA binding to calcium causing it to be excreted
- Vit D deficiency
Drugs
- Inhibition of Bone resorption e.g. Bisphosphonates
- Calcium chelators (increase excretion)
- Phenytoin (inactivates Vitamin D)