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
