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Basics ⬇

Basics

Overview

  • Post-parturient hypocalcemia.
  • Usually develops 1–4 weeks postpartum; may occur at term, prepartum, or during late lactation.
  • Alters cell membrane potentials, causing spontaneous discharge of nerve fibers and tonic-clonic contraction of skeletal muscles.
  • Life-threatening tetany and convulsions, leading to hyperthermia.
  • Cerebral edema possible.

Signalment

  • Dog-postpartum bitch; most common in toy breeds; higher incidence with first litter.
  • Most common prior to day 40 postpartum; occasionally occurs prepartum.
  • Breeds at increased risk: Chihuahua, miniature pinscher, Shih Tzu, miniature poodle, Mexican hairless, Pomeranian.
  • Cat-rare.

Signs

Historical Findings

  • Poor mothering
  • Restlessness, nervousness
  • Panting, whining
  • Vomiting, diarrhea
  • Ataxia, stiff gait, limb pain
  • Facial pruritis
  • Muscle tremors, tetany, convulsions
  • Recumbency, extensor rigidity-usually seen 8–12 hours after onset of signs.

Physical Examination Findings

  • Hyperthermia
  • Rapid respiratory rate
  • Dilated pupils, sluggish pupillary light responses
  • Muscle tremors, muscular rigidity, convulsions

Causes & Risk Factors

  • Calcium supplementation during gestation, including dairy products
  • Inappropriate Ca:P ratio in gestational diet
  • Low body weight:litter size ratio
  • Poor prenatal nutrition
  • First litter
  • Large litter size

Diagnosis ⬆ ⬇

Diagnosis

Differential Diagnosis

  • Hypoglycemia-may be concurrent; hypoglycemia alone does not cause muscular rigidity.
  • Toxicosis-distinguished by signalment and history.
  • Epilepsy or other neurologic disorder-differentiated by signalment; calcium concentration diagnostic.

CBC/BIOCHEMISTRY/URINALYSIS

  • Total serum calcium <9 mg/dL in bitches; <8 mg/dL in queens.
  • Although ionized calcium (<2.4–3.2 mg/dL) is the form important for normal neuromuscular function, measurement of total serum calcium is usually sufficient for diagnosis.
  • Hypoglycemia-may be concurrent.
  • Hypomagnesemia has been reported in 44% of affected bitches; may promote tetany.
  • Serum potassium elevated in 56% of cases, due to metabolic acidosis or respiratory alkalosis.

Imaging

N/A

Other Laboratory Tests

N/A

Diagnostic Procedures

ECG shows prolonged QT interval, bradycardia, tachycardia, or ventricular premature complexes.

Treatment ⬆ ⬇

Treatment

Medications ⬆ ⬇

Medications

Drug(s)

  • Calcium gluconate-10% solution 0.22–0.44 mL/kg IV given slowly to effect over 5 minutes; monitor heart rate or ECG during administration.
  • Correct hypoglycemia.
  • Diazepam 5 mg IV; for unresponsive seizures.
  • Cerebral edema-treat, if indicated.
  • Send home on calcium carbonate, or gluconate 10–30 mg/kg PO q8h until lactation ends (calcium carbonate (TUMS) 500 mg tablets supply 200 mg calcium).
  • Magnesium supplementation may be helpful in hypomagnesemic bitches.
  • Start puppies/kittens on solid food at 3–4 weeks of age.

Contraindications/Possible Interactions

Corticosteroids-avoid; cause decreased intestinal absorption and increased renal excretion of calcium.

Follow-Up ⬆ ⬇

Follow-Up

Patient Monitoring

  • Serum calcium concentration-monitor until it is stabilized in the normal range.
  • Avoid calcium supplementation during gestation.
  • Diet-maternal: ensure a calcium:phosphorus ratio of 1:1 or 1.2:1; avoid high-phytate foods (e.g., soybeans); puppies: supplement feeding for large litters.

Possible Complications

  • Cerebral edema
  • Death
  • Hand-raising of puppies

Expected Course and Prognosis

  • Probably will recur with subsequent litters; calcium supplementation can be started after parturition for bitches with history of eclampsia in prior litters.
  • Prognosis-good with immediate treatment; poor with delayed treatment.

Miscellaneous ⬆

Miscellaneous

Abbreviation

ECG = electrocardiogram

Author Joni L. Freshman

Consulting Editor Sara K. Lyle

Suggested Reading

Davidson AP. Reproductive causes of hypocalcemia. Topics Compan Anim Med 2012, 27:165–166.

Drobatz KJ, Casey KK. Eclampsia in dogs: 31 cases (1995–1998). J Am Vet Med Assoc 2000, 217(2):216–219.

Johnston SD, Kustritz MVR, Olson PN. Periparturient disorders in the bitch. In: Johnston SD, Kustritz MVR, Olson PN, eds., Canine and Feline Theriogenology. Philadelphia: Saunders, 2001, pp. 129–145.