Puerperal Tetany (Eclampsia)

Puerperal Tetany (Eclampsia) is also known as Periparturient hypocalcemia. It is generally occurs within the first 2 weeks postpartum, but can also occur in the prepartum period in female dogs.

Etiology

• Improper perinatal nutrition of the bitch.
• Calcium supplementation of the bitch during gestation.
• Heavy lactational demands from large neonates or a large litter.
• Increased incidence in toy breeds of dogs.

Pathophysiology

• Altered membrane potentials from hypocalcemia allow spontaneous discharge of nerve fibers and tonic contractions of skeletal muscle.
• Hypoglycemia can occur concurrently.
• Exacerbated by metabolic conditions favoring protein binding of serum calcium, e.g., alkalosis.
• Prolonged seizure activity may cause cerebral edema.

Clinical Signs

• Initial signs include behavioral changes (irritability and restlessness), salivation and facial pruritus.
• Signs progress to ataxia and muscle spasms.
• Tonoclonic muscle contractions of seizures occur and may be associated with hyperthermia and tachycardia.
• The bitch (female dog) may remain obtunded or non responsive after correction of hypocalcemia if cerebral edema has developed.

Diagnosis

• Clinical signs and history allow a presumptive diagnosis.
• A pretreatment serum sample is collected for confirmation of hypocalcemia, but treatment is often required prior to laboratory confirmation.
• Serum calcium in affected dogs generally ranges from 4.0-7.5 mg/dl.
• Evaluate serum glucose concentration for evidence of concurrent hypoglycemia.

Differential Diagnosis

• Rule out other causes of seizures such as hypoglycemia, toxicoses and primary neurologic disorders, e.g., epilepsy.
• Consider other causes of irritability and hyperthermia such as metritis or mastitis.

Treatment

Administer 10% calcium gluconate IV slowly to effect over 3-5 minutes:

• A total dose of 1-20 ml is generally required.
• Monitor heart rate with auscultation or electrocardiogram (ECG)
• If an arrhythmia develops discontinue administration until rhythm and rate are normal and resume administration at half the original infusion rate.
• Muscle relaxation should be immediate.

If calcium infusion is ineffective, consider administering diazepam 1-15 mg.

• Treat cerebral edema if indicated.
• Correct hyperthermia and hypoglyccmia if present.
• Once stable, repeat the dose of calcium gluconate SQ diluted in an equal volume of normal saline, and repeat as needed TID to control clinical signs.
• Oral supplementation with calcium lactate, carbonate, or gluconate 30-100 mg/kg/day is begun and continued until lactation ceases.
• Consider weaning or providing pups with supplemental nutrition to decrease lactational demands.
• Provide a balanced diet for the bitch with a commercial food designed for use during lactation or growth.

Patient Monitoring

• Warn owners that this condition is likely to recur with future pregnancies.
• Calcium supplementation during gestation will not prevent and may contribute to the development of eclampsia.