Disorders of calcium metabolism (TV4101, Lecture 9 Notes)

Define HARD IONS (hypercalcaemia)

H - Hyperparathyroidism/humoral

A - Addison's

R - Renal

D - Vitamin D

I - Idiopathic

O - Osteolytic bone destruction

N - Neoplasia

S - Spurious

List the three fractions of serum calcium

1. Protein-bound (i.e. albumin)

2. Complexed with organic anions (i.e. citrate/sulphate)

3. Ionised calcium (biologically fraction subject to regulation)

i.e. total calcium screening test only, not indicative of true hypercalcaemia.

List causes of hypercalcemia

- Spurious/young growing animals

- Humoral hypercalcemia of malignancy (HHM)

- Hypoadrenocorticism

- Primary hyperparathyroidism (PHPTH)

- Chronic kidney disease (CKD)

- Idiopathic hypercalcemia of cats

- Apocrine gland anal sac adenocarcinoma (AGASAC) or multiple myeloma (MM)

- Vitamin D toxicity

- Granulomatous diseases

Describe how cancers cause hypercalcemia

- Production of parathyroid-related peptide (PTHrP)

- Bone destruction

List the clinical signs of primary hyperparathyroidism in dogs

- LUTD (stranguria, pollakiuria, hematuria)

- Pu/Pd

- Weakness

- Exercise intolerance

- Listlessness

- Overflow incontinence 2nd to polyuria

- Inappetence

- Weight loss

- Muscle wasting

- Vomiting

- Shivering

- Constipation

- Stiff gait

List the biochemistry findings of primary hyperparathyroidism

- Increased total and ionised calcium

- Increased PTH

- No azotaemia or phosphateamia

Discuss the treatment of hypercalcemia

Discuss the surgical treatment of hypercalcemia

- Ensure removal of all four glands

- Screen for hypocalcemia

List the clinical signs of acute onset hypocalcemia

- Panting

- Nervousness/anxiety

- Muscle trembling/twitching

- Leg cramping/pain

- Ataxia

- Atypical aggressive behaviour

- Stiff gait

- Facial rubbing

- Biting at feet

- Voacialising

- Hypersensitivity

- Focal or generalised seizures

Discuss the signalment of hypoparathyroidism

- Most common in toy poodles

- Expect in GSD, labradors, mini schnauzer and terriers

List the clinical signs of hypoparathyroidism

- Seizures

- Pawing, rubbing and licking

- Hyperthermia

- Stiff gait

- Generalised muscle fasciculations

- Growling

- Tachypnoea

- Muffled heart sounds/weak pulses

- Cataracts

List biochemical abnormalities of hypoparathyroidism

- Decreased total Ca

- Decreased ionised Ca

- Increased phosphate

- Decreased PTH

Discuss treatment for acute tetany

Discuss chronic management of hypocalcemia