Hypercalcaemia Flashcards
What is involved in the regulation of calcium?
- PTH (neg feedback by iCa)
- Calcitriol (promoted by PTH, inhibited by FGF23)
- Calcitonin
What are the possible causes of hypercalcaemia?
- Increased PTH activity: primary hyperparathyroidism
- Increased Vit D activity: dietary/ toxin
- Osteolysis: local destruction of bone
- Hypoadrenocorticism
What is PTHrP?
- PTH related protein
- Produced by cartilage, bone, muscle, epithelium, CNS
List some differential diagnoses for hypercalcaemia
- Parathyroid adenoma
- Parathyroid hyperplasia
- Vit D excess
- Osteolysis
- Raisin toxicity
What are the causes of total hypercalcaemia in dogs?
- Malignancy (most common)
- Hypoadrenocorticism
- Primary hyperparathyroidism
- Chronic renal failure
- Vit D toxicosis
- Granulomatous disease(least common)
What are the causes of hypercalcaemia in cats?
- Idiopathic hypercalcaemia (most common)
- Renal failure
- Malignancy
- Primary hyperparathyroidism (least common)
What are the causes of hypercalcaemia in horses?
-Chronical renal failure (most common)
-Vit D toxicosis
-Hypercalcaemia of malignancy
Primary hyperparathyroidism (least common)
What are the clinical signs of hypercalcaemia?
- PU/PD (antagonism of ADH)
- Weakness
- Depression (decreased excitability of nervous tissue)
- Anorexia
- Constipation (decrease in the excitability of GI smooth muscle)
- Muscle twitching, shivering, seizures
- Bradycardia
- SOFT TISSUE MINERALISATION
How do you diagnose hypercalcaemia?
- Review history= focus on diet and access to vit D
- Look at signalment
- Clinical exam- check lymph nodes, anal sac masses, angiostrongylus
Discuss how the total calcium, iCa and phosphorus concentrations in blood would be affected in PTH/ PTHrH excess cases
- Total calcium= increase
- ICa= increasd
- Phosphorus= decreased
Discuss how the total calcium, iCa and phosphorus concentrations in blood would be affected in Vit D excess cases
- Total calcium= elevated
- iCa= elevated
- Phosphrus= elevated
What are the clinical signs of soft tissue mineralisation?
-Vomiting, anorexia, lethargy PU/PD -Acute renal failure -Death -Seizures
FACTSHEET
Need to distinguish between PTH dependant and PTH independent hypercalcaemia (if calcium stays high when PTH is low= independent)
What affects does hypoadrenocorticism normally have on calcium levels?
Normally only raises total calcium= ionised calcium usually remains normal
Describe idiopathic hypercalcaemia
- Occurs in young to middle ages cats
- Phosphorus is normal
- Intact PTH normal or lowered
- PTHrP undetectable
- Vit D3 normal
- Both total and ionised calcium elevated
What PTH concentration would you expect to see in an animal with secondary renal hyperparathyroidism?
Either lowered ICa or normal
whereas in primary hyperparathyroidism you expect to see increased calcium
