Calcium regulation Flashcards
PTH is secreted from what type of cell?
Chief cells of the parathyroid hormone which have calcium and vit d receptors
What are the actions of PTH?
Activates osteoclasts, acts on kidneys to stimulate reabsorption of calcium, stimulates activation Vit D
Draw the vitamin d activation pathway.
What are the causes for hypercalcaemia?
C- Calcium supplementation
H- Hyperparathyroidism
I- Iatrogenic (thiazides)
M- Milk alkali syndrome
P- Paget disease of the bone
A- Acromegaly and Addisons disease
N- Neoplasia
Z- Zollinger Ellison syndrome
E- Excessive vit A
E- Excessive vit D
S- Sarcoidosis
What are the signs and symptoms of acute hypercalcaemia?
Renal - polyuria and polydipsia
Gastrointestinal- anorexia, vomiting, constipation, abdominal pain
CNS- confusion, lethargy, depression
What are the signs and symptoms of chronic hypercalcaemia?
Renal - polyuria, polydipsia, stones
Gastrointestinal- anorexia, vomiting, constipation, abdominal pain
CNS- confusion, lethargy, depression
Bone pain, fracture
What is the management of hypercalcaemia?
6L 0.9% Saline over 24 hours
IV bisphosphonate (Zolendronate 4mg).
If the pt is resistant to bisphosphonates then they should receive Im calcitonin or PO steroids
What are the causes of hypocalcaemia?
Acute pancreatitis
Hypoparathyroidism
What condition can chronic hypocalcaemia lead to?
Osteomalacia
What are the signs and symptoms of hypocalcaemia?
Bone and muscle pain
Proximal myopathy
Neuromuscular irritability- parasthesia, dystonia, anxiety, tetany, convulsions, Trousseau and Chvostek’s signs
Calcium>3 is almost always what?
Malignancy
High calcium with low phosphate is indicative of what?
Hyperparathyroidism
High calcium with high phosphate could be which 4 things?
Myeloma, Vitamin D excess, bony malignancy, sarcoidosis
High calcium with high ALP could be which 3 things?
Bone metastasis, sarcoidosis, lithium toxicity
High calcium with high PTH indicates what? What 3 conditions can cause this?
Parathyroid overactivity.
Hyperparathyroidism, familial hypocalcuric hypercalcemia, lithium toxicity
What ECG changes are present in hypercalcaemic patients?
Short QT intervals
What are Trosseau and Chvosteks signs?
- Chvostek’s sign is the twitching of the facial muscles in response to tapping over the area of the facial nerve.
- Trousseau’s sign is carpopedal spasm caused by inflating the blood-pressure cuff to a level above systolic pressure for 3 minutes.
What are the investigations of low calcium?
Corrected albumin as hypocalcaemia is usually an artefact of low albumin
PTH
Phosphate, vitamin D and magnesium
Low calcium with high phosphate indicates?
CKD, hypoparathyroidism, vit D deficiency, hypomagnasaemia
Low calcium with low phosphate indicates?
Pancreatitis, bone disease
What ECG changes are present low calcium?
Long QT
How is low calcium managed?
In the emergency department, magnesium and calcium (in their many different forms) are the only medications necessary to treat hypocalcemic emergencies. The consulting endocrinologist may choose to prescribe any of the various vitamin D supplements depending on laboratory workup findings, and oral calcium supplementation for outpatient therapy.
