Calcium-related clinical conditions Flashcards by Naseem Basit

What is the function of calcium in the blood?

It is clotting factor 4

involved in the clotting cascade

How well did you know this?

Not at all

Perfectly

What does a calcium chelator do?

Binds calcium

How well did you know this?

Not at all

Perfectly

What are some examples of calcium chelators?

EDTA

Citrate

How well did you know this?

Not at all

Perfectly

How is EDTA used clinically? Why?

Put into blood tubes

to prevent blood from clotting

How well did you know this?

Not at all

Perfectly

How is citrate used clinically? Why?

Put into blood bags

to prevent blood from clotting

How well did you know this?

Not at all

Perfectly

Patients who are given large blood transfusions must also be given what? Why?

IV calcium

to compensate for the calcium chelated by citrate
so patients blood can clot

How well did you know this?

Not at all

Perfectly

In blood test results, which serum calcium value is looked at?

The adjusted/corrected one

How well did you know this?

Not at all

Perfectly

What is the most common cause of hypercalcaemia?

Malignancies that have metastasised to bone

and are osteolytic

How well did you know this?

Not at all

Perfectly

What are some cancers that commonly metastasise to bone? Which ones are osteolytic?

Breast cancer - osteolytic

Lung cancer - osteolytic

Renal cancer - osteolytic

Thyroid cancer - osteolytic

Prostate cancer

How well did you know this?

Not at all

Perfectly

How does prostate cancer affect bone?

It is osteoblastic

How well did you know this?

Not at all

Perfectly

Which bones are most commonly invaded by metastases?

Skull

Ribs

Vertebrae

Pelvis

Proximal femur

Proximal humerus

How well did you know this?

Not at all

Perfectly

What are the types of hyperparathyroidism?

Primary

Secondary

How well did you know this?

Not at all

Perfectly

What causes primary hyperparathyroidism?

One of four parathyroid glands develops adenoma

secretes excessive PTH

How well did you know this?

Not at all

Perfectly

What are the consequences of excessive PTH secretion in primary hyperparathyroidism?

Serum calcium rises

Serum phosphate falls

How well did you know this?

Not at all

Perfectly

What is the cause of secondary hyperparathyroidism?

All four parathyroid glands undergo hyperplasia

How well did you know this?

Not at all

Perfectly

Secondary hyperparathyroidism is seen in patients with?

Vitamin D deficiency

How well did you know this?

Not at all

Perfectly

What are the causes of vitamin D deficiency?

Dietary - reduced intake

Environmental - reduced exposure to sun, darker skin

Chronic kidney failure

How well did you know this?

Not at all

Perfectly

Why does chronic kidney failure cause vitamin D deficiency?

Failure of second hydroxylation reaction

25-hydroxyvitamin D —–> calcitriol

How well did you know this?

Not at all

Perfectly

How does vitamin D deficiency affect serum calcium levels?

Reduced calcium absorption

low serum calcium levels

How does vitamin D deficiency affect PTH levels?

Low serum calcium levels

causes PTH levels to rise

What are the consequences of raised PTH levels?

Calcium mobilised from bone

to increase serum calcium levels

What are the symtpoms of vitamin D deficiency?

Bone pain due to osteomalacia with vitamin D deficiency

Bone pain due to renal osteodystrophy with chronic kidney failure

What are the symptoms of primary hyperparathyroidism?

Moans - tired, depressed

Groans - constipation, peptic ulcers, pancreatitis

Stones - kidney stones, polyuria

Bones - bone pain

What causes polyuria in primary hyperparathyoidism?

Impaired sodium and warer reabsorption

due to kidney stones

How does hypercalcaemia affect neurone membrane depolarisation?

High calcium makes outside of neurone relatively more positive raises threshold for depolarisation suppresses depolarisation

How does hypocalcaemia affect neurone membrane depolarisation?

Low calcium makes outside of neurone relatively less positive reduced threshold for depolarisation neurone membrane more excitable

What is classed as severe hypercalcaemia?

Serum calcium levels more than >3mM

What are the symptoms of severe hypercalcaemia?

Lethargy, weakness Confusion Coma Renal failure Polyuria

How does polyuria affect hypercalcaemia?

Leads to dehydration | which exacerbates the hypercalcaemia

How is severe hypercalcaemia treated?

Rehydration

Hypocalcaemia is seen most commonly in what group of patients? Why?

Post total thyroidectomy patients because of accidental removal of parathyroid glands

When do symptoms of hypocalcaemia develop?

When serum calcium falls below 2.10 mmol/L Within 6 hours of thyroidectomy even

What are the symptoms of hypocalcaemia?

Tingling around mouth, in fingers Carpopedal spasms - spasms of hands and feet

What is a sign of hypocalcaemia?

Chvostek's sign - tapping over facial nerve gives facial twitching

How can hypocalcaemia be fatal?

Laryngeal muscle tetany

How is bone density affected in osteoporosis?

Reduced bone density

How is the mineral:matrix ratio affected in osteoporisis?

Normal mineral:matrix ratio

How does osteoporosis occur?

Destruction of bone that has already been fully constructed

What are the consequences of osteoporisis?

Brittle bones that are more prone to fracture

How is the mineral:matrix ratio affected in osteomalacia?

Reduced mineral:matrix ratio | due to reduction in mineral content

What is osteomalacia called in children?

Rickets

What are the consequences of rickets?

Deformed bones

What are the consequences of osteomalacia in adults?

Soft bones, prone to bending

What are the causes of osteomalacia/rickets?

Vitamin D deficiency

What are the symptoms of osteomalacia in adults?

Bone pain Muscle weakness

What are the risk factors of osteoporosis?

Post-menopausal women Low BMI Long-term oral steroid use Smoking, heavy drinking Prolonged inactivity

Which bones are more commonly fractured in osteoporosis?

Hip fractures Wrist fractures Vertebral fractures