Introduction
Calcium is the most abundant mineral in body and, together with phosphorus, forms the hard material of healthy bones and teeth. Calcium has many other vital roles, including control of the permeability of cell membranes, blood clotting, maintenance of normal heartbeat and initiation of muscular and metabolic activities. Eclampsia, which is also called “puerperal hypocacemia” or “puerperal tetany,” is an acute and extremely severe condition in lactating female dogs caused by abnormally low calcium levels. It most commonly occurs in small-breed bitches with large litters, during the period of peak lactation - within the first month after the puppies are born – although all sizes and breeds can be affected. If not treated in a timely manner, the condition can be fatal.
Causes of Eclampsia
The signs of eclampsia are a direct result of low blood calcium concentrations (hypocalcemia). The precise reasons for the hypocalcemia are not well understood, but they are somehow connected with the heavy loss of maternal calcium into the developing fetal skeletons during pregnancy and then into the milk during lactation. Poor nutrition during pregnancy, poor utilization by the bitch of dietary calcium and/or inappropriate calcium or other supplementation, may also contribute. The stresses of whelping, nursing and raising a litter – especially for a young first-time mother – can reduce her appetite, thereby causing inadequate dietary calcium.
Prevention of Eclampsia (Puerperal Hypocalcemia) in Female Dogs
Although not proven to be 100% effective, there are several steps that owners of pregnant dogs can take to reduce the risk of eclampsia. First and foremost is to feed a complete, high-quality, highly digestible and nutritionally balanced diet, both during pregnancy and while the puppies are nursing. The mother should have free access to fresh, clean water and to food while she is lactating. If necessary, the pups can be removed from her for 30 minutes or so several times a day to give her some privacy and encourage her to eat. The owner can also supplement the puppies with a milk replacement formula to reduce the demands on the bitch.
Pregnant bitches on a complete, balanced diet should not need or be given oral calcium supplementation. While it may seem counterintuitive, giving extra calcium during pregnancy has been shown to increase, not decrease, the risk of puerperal hypocalcemia in female dogs.
Diagnosis of Eclampsia (Pueperal Hypocalcemia) in Female Dogs
Most cases of eclampsia are diagnosed based on the finding of certain clinical signs and physical examination findings in a heavily lactating bitch. If the patient is a young, small-breed dog that whelped a large litter within the past few weeks, the index of suspicion for eclampsia is raised. Because this is such an acute-onset and life-threatening condition, most veterinarians will initiate treatment based on clinical signs and physical exam findings alone, although eclampsia can be confirmed by measuring the concentration of calcium in the blood (with eclampsia, it will be abnormally low). Perhaps the best diagnostic tool is assessing the bitch’s response to intravenous calcium replacement therapy.
Outlook for Dogs with Puerperal Hypocalcemia
The prognosis for puerperal hypocalcemia depends on how advanced the condition is. Cases that are treated early have an excellent prognosis, but the illness is fatal if it is not treated it in a timely manner.