Hypocalcemia in Small Animals

Definition & Core Metrics:

General Definition: A condition where serum calcium concentrations fall below specific thresholds.
Thresholds (Animals <6 months old):
- Dogs: <9 mg/dL.
- Cats: <7 mg/dL.
Ionized Calcium (iCa): The biologically active form; hypocalcemia is diagnosed when iCa is <1 mmol/L.
Influencing Factors:
- Acid-Base Status: Alkalosis decreases iCa, while acidosis increases it.
- Plasma Protein: Hypoalbuminemia decreases total serum calcium, but iCa remains unaffected.
- Laboratory Error: Lipemia can affect results.

Etiology:

Endocrine & Organ Dysfunction:
- Hypoparathyroidism (including iatrogenic cases post-thyroidectomy).
- Acute or chronic renal failure.
- Acute pancreatitis.
- Hyperadrenocorticism.
Nutritional & Absorption Issues:
- Intestinal malabsorption.
- Nutritional secondary hyperparathyroidism.
Reproductive & Critical Care:
- Eclampsia (puerperal tetany).
- Critically ill patients and those with abdominal trauma.
- Induced endotoxemia (leads to hypovitaminosis D and metabolic acidosis).
Toxins & Drugs: Ethylene glycol, piperazine, and phosphate enemas.

Clinical Findings:

Range of Severity: Can vary from no signs to severe neuromuscular dysfunction.
Behavioral & Minor Signs: Anorexia, facial rubbing, growling, nervousness, and stiff gait.
Neuromuscular Signs: Focal muscle twitching (ear and face), tremors, spasms, tetany, and seizures.
Cardiovascular Signs: Potential cardiovascular collapse in critical cases.
Aggravating Factors: Clinical signs may be worsened by exercise or excitement.
Determinants of Severity: Magnitude of the deficiency, rapidity of onset, and duration.

Diagnosis:

Clinical Assessment: Based on history and physical examination.
Laboratory Testing:
- Serum biochemical testing (including serum lipase concentration).
- Urinalysis.
- Diagnostic Confirmation: Ionized calcium concentration <1 mmol/L.

Treatment & Prevention

Primary Goal: Correct the underlying disorder.
Intervention Thresholds: Treatment is indicated if total serum calcium is <7.5 mg/dL or iCa is <0.8 mmol/L.
Therapeutic Actions:
- Vitamin D supplementation.
- Calcium supplementation (especially if clinical signs are present).

Hypocalcemia in Small Animals

Definition & Core Metrics:

General Definition: A condition where serum calcium concentrations fall below specific thresholds.

Thresholds (Animals <6 months old):

Dogs: <9 mg/dL.

Cats: <7 mg/dL.

Ionized Calcium (iCa): The biologically active form; hypocalcemia is diagnosed when iCa is <1 mmol/L.

Influencing Factors:

Acid-Base Status: Alkalosis decreases iCa, while acidosis increases it.

Plasma Protein: Hypoalbuminemia decreases total serum calcium, but iCa remains unaffected.

Laboratory Error: Lipemia can affect results.

Etiology:

Endocrine & Organ Dysfunction:

Hypoparathyroidism (including iatrogenic cases post-thyroidectomy).

Acute or chronic renal failure.

Acute pancreatitis.

Hyperadrenocorticism.

Nutritional & Absorption Issues:

Intestinal malabsorption.

Nutritional secondary hyperparathyroidism.

Reproductive & Critical Care:

Eclampsia (puerperal tetany).

Critically ill patients and those with abdominal trauma.

Induced endotoxemia (leads to hypovitaminosis D and metabolic acidosis).

Toxins & Drugs: Ethylene glycol, piperazine, and phosphate enemas.

Clinical Findings:

Range of Severity: Can vary from no signs to severe neuromuscular dysfunction.

Behavioral & Minor Signs: Anorexia, facial rubbing, growling, nervousness, and stiff gait.

Neuromuscular Signs: Focal muscle twitching (ear and face), tremors, spasms, tetany, and seizures.

Cardiovascular Signs: Potential cardiovascular collapse in critical cases.

Aggravating Factors: Clinical signs may be worsened by exercise or excitement.

Determinants of Severity: Magnitude of the deficiency, rapidity of onset, and duration.

Diagnosis:

Clinical Assessment: Based on history and physical examination.

Laboratory Testing:

Serum biochemical testing (including serum lipase concentration).

Urinalysis.

Diagnostic Confirmation: Ionized calcium concentration <1 mmol/L.

Treatment & Prevention

Primary Goal: Correct the underlying disorder.

Intervention Thresholds: Treatment is indicated if total serum calcium is <7.5 mg/dL or iCa is <0.8 mmol/L.

Therapeutic Actions:

Vitamin D supplementation.

Calcium supplementation (especially if clinical signs are present).