Calcium Metabolism 2 Flashcards
What are the symptoms of hypercalcaemia?
Polyuria / Polydipsia (Osmotic Diuresis) Band Keratopathy – Calcification in front of eye Constipation Neurological (Normally kick in later i.e. Ca+>3.0mmol/L) -> Confusion -> Seizures -> Coma -> Depression
What are the causes of hypercalcaemia?
PTH NORMAL/HIGH.
-> Primary Hyperparathyroidism (Most Common in Community)
Others;
i) Familial Hypocalciuric Hypercalcaemia (Rare)
PTH 0/LOW.
-> Malignancy (Most Common in Hospital)
Others;
i) Thyrotoxicosis - Bone Resorption
ii) Hypoadrenalism i.e. Addison’s - Renal Calcium reabsorption
iii) Thiazide Diurectics - Renal Calcium Reabsorption
iv) Sarcoidosis - Non Renal 1 alpha hydroxylation
v) Excess Vitamin D - Sunbeds etc.
What is the management of hypercalcaemia?
Acutely
If Ca > 2.8mmol/L
-> Drink lots of water to manage the Hypercalcaemia
If Ca > 3.0mmol/L -> Emergency!
- > IV Access
- > Catheter
- > Rehydrate, 0.9% Saline 1L/1hour (usually 4-6litres are given in 24hours)
*Saline causes Calciuresis, if overloaded - give Furosemide and Saline
What should you not give to a patient with hypercalcaemia?
Do NOT use Thiazide Diuretics – reduces Calciuresis
Do NOT use IV Zolendronate Acutely – Ruins future PTH readings
What are some complications of hypercalcaemia?
- > Renal Stones
- > Pancreatitis
- > Peptic Ulcer Disease
- > Skeletal Changes i.e. Pepper Pot Skull (High PTH)
- > Osteitis Fibrosa Cystica (Increased bone turnover)
What is Primary Hyper-parathyroidism?
An increased activity of the parathyroid gland leading to increased PTH release
Typically a Parathyroid Adenoma (85%) however may also be
- > Hyperplasia (MEN 1)
- > Carcinoma
Typically affects F>M
What are the symptoms of Primary Hyper-parathyroidism?
- > Bones - PTH Bone Disease
- > Stones - Renal Caliculi
- > Moans - HyperCa. Abdominal Pain
- > Groans - HyperCa. Confusion
What are some signs of Primary Hyper-parathyroidism?
- > Raised PTH
- > Raised Ca
- > Urine Ca
- > Low Serum Phosphate (Phosphate Trashing Hormone)
- > Radial Aspect Cystic Changes -> progress -> changes in Random Carpal Bones
- > Multinucleate Giant Cells – overactive Osteoclasts
What are some investigations for Primary Hyper-parathyroidism?
- > 99Tc SestaMIBI Scan -> Radioactive Isotope
- > USS
What is the management for Primary Hyper-parathyroidism?
-> Parathyroidectomy (if due to Pituitary Adenoma)
What is Familial Hypocalciuric Hypercalcaemia?
-> Mutation in the CaSr - Calcium Sensing Receptor
Parathyroid Hormone only stops releasing PTH at higher levels of Calcium
- > Constant Mild Hypercalcaemia
- > No raised Urine Calcium
- > Asymptomatic*
*All the cells in the body have the mutated CaSr, therefore the whole body continues as normal
What are three main ways in which malignancies can lead to Hypercalcaemia?
i) Humoral Hypercalcaemia of Malignancy (Small Cell lung Ca)
- > Release of Ectopic PTH like peptides i.e. PTH rP
ii) Bone Metastases (i.e. from a Breast Cancer)
- > Local bone osteolysis
iii) Haematological Malignancy (i.e. Myeloma)
- > The cytokine release from a blood cancer can cause the bone to break up
How does sarcoidosis cause hypercalcaemia?
The presence of 1-alpha hydroxylase in the lung macrophages, constantly activating Vitamin D.
-> Bilateral Hilar Lymphadenopathy
What are the symptoms of sarcoidosis?
These patients typically present with seasonal hypercalcaemia, as Sarcoid is prevalent in Afro-Carribeans, who are Vitamin D deficient during the Winter.
Treatment for sarcoidosis?
-> High Dose Steroids – 40mg Prednisolone
