Metabolism Week 6 Andra

Metabolism Week 9 Med23

Endocrine Control of Calcium Homeostasis

Multiple Select

What are the forms of serum Calcium?

Choose the correct answers.

• Bound to

  anionic site of proteins

• Bound to

  albumin

• Free ionised

• Bound to

  low molecular anions

.Calcium bound to anionic sites on serum proteins (eg albumin)

= 40% of the serum calcium

​Bound to proteins

Is the biologically active form

= 50% of the total Calcium

Free ionised

Forms of serum Calcium

Bound to low molecular anions

Complexed with low molecular weight organic anions (phosphate, citrate, oxalate)

= 10% of total serum calcium

Factors which Influence the Concentration of Ionised Calcium

Albumin	increased albumin = decreased ionised calcium
pH	increased pH = decreased ionised calcium
Lactate	increased lactate = decreased ionised calcium
Phosphate	increased phosphate = decreased ionised calcium
Bicarbonate	increased bicarbonate = decreased ionised calcium
Citrate	increased citrate = decreased ionised calcium
Heparin	Presence of heparin in the sample = decreased ionised calcium
Free fatty acids	Increase in free fatty acids = decreased ionised calcium

derangedphysiology.com

By Alex Yartsev - Jun 09, 2015

Last updated Wed, 12/08/2021 - 17:42
Topic: Body fluids and electrolytes

Multiple Select

HORMONAL regulation of Serum Calcium is done by:

• PTH (Parathormone)

• CALCITRIOL

• VITAMIN D

• CALCITONINE

PTH = parathormone

Calcitriol = is the active form of vitamin D, normally made in the kidney. It is also known as 1,25-dihydroxycholecalciferol. It is a hormone which binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the expression of many genes. Calcitriol increases blood calcium (Ca²⁺) mainly by increasing the uptake of calcium from the intestines.

Calcitonin (aka thyrocalcitonin) = is a hormone that is produced by the parafollicular cells (commonly known as C-cells) of the thyroid gland. Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone.

Multiple Choice

A patient was diagnosed with papillary thyroid carcinoma. Bilateral thyroidectomy (surgery) was performed. Immediate post-op HYPOcalcemia is most likely to be caused by: (one answer)

• Lack of thyroid hormones

• Accidental removal of the parathyroid glands

• Inappropriate i.v. drip

• Methastasis

Follow protocols for Acute hypocalcemia

Postoperative care for total thyroidectomy patiens include monitoring of ADJUSTED (corrected) calcium: check within 12 hours post-op

Normal: 2.20 -2.60 mmol/L

Mild: 2.00 - 2.19

Moderate: 1.91 - 1.99

Severe <= 1.90 (needs iv replacement)

Remember the SE of hypocalcemia: tetany, ECG changes with arrhythmia, Seizure. It starts most commonly with paraesthesia (fingers, around mouths).

Multiple Select

Same patient. Severe HYPOcalcemia was treated with an iv infusion of CALCIUM GLUCONATE. They can present side effects:

• Hypotension

• Sweating

• Chalky taste

• Arrhythmias

Side effects of calcium gluconate include: www.rxlist.com

• nausea,

• vomiting,

• decreased appetite,

• constipation, OR Diarrhoea

• dry mouth,

• increased thirst,

• increased urination,

• tingling sensations,

• hot flashes, and

• a chalky taste following intravenous administration.

https://bnfc.nice.org.uk/drugs/calcium-gluconate

For all calcium salts

Uncommon

Constipation; diarrhoea; hypercalcaemia; nausea

Side-effectsFor calcium gluconate

General side-effects:

Frequency not known

Arrhythmias

Specific side-effects:

Frequency not known

With intravenous use

Circulatory collapse; feeling hot; hyperhidrosis; hypotension; vasodilation; vomiting

With oral use

Gastrointestinal disorder

Thank You!