Diagnosis of Excess Magnesium in the Blood in Dogs
A blood test will measure the total serum concentration of magnesium as well as the concentration of magnesium ions (generally considered more accurate since this is the active form of magnesium). Other electrolytes levels will be measured at the same time since ions in the blood frequently interact and other conditions like hypocalcemia and hyperkalemia can cause similar symptoms.
The veterinarian will try to determine the underlying cause of the problem. Urinalysis will test kidney function and determine if magnesium is being excreted effectively. Hormone imbalances will often be visible on a blood test. Other tests may be ordered to check the function of certain glands. An echocardiogram will evaluate heart function and diagnose fluid in the pericardial cavity.
Overuse of laxatives or overdose on human medications can cause hypermagnesemia. The veterinarian will need to know if your dog has been exposed to these drugs, especially if other tests come back negative. If no other cause is found, a second blood test may be necessary since false positives can happen due to red blood cells bursting during the testing process.
Symptoms of Excess Magnesium in the Blood in Dogs
Mild hypermagnesemia can often be asymptomatic, but very high levels will present serious life-threatening symptoms that should be treated as an emergency.
Types
The veterinarian will categorize your dog’s hypermagnesemia based on its severity.
What is Excess Magnesium in the Blood?
Magnesium is very important positive ion that is vital for many cellular processes. The majority of the magnesium in the body is found inside the cells, especially the bones, but about 1 % circulates in the blood stream, either as an active ion (55%) or bound to proteins and other complex molecules. Excess magnesium in the blood, called hypermagnesemia, can be a very serious problem since magnesium limits the function of calcium ions. This leads to muscle weakness, abnormal heart rhythms, and eventually respiratory paralysis and cardiac arrest. Magnesium is normally excreted by the kidneys. In dogs, normal kidney function will maintain a typical magnesium serum concentration below 2.5 mg/dl, even if high levels of magnesium are ingested. Severe renal failure is the most common reason for blood magnesium levels to rise. This is frequently a problem if dogs with kidney failure receive IV fluids high in magnesium. Some endocrine imbalances or a pericardial effusion (fluid inside the heart cavity) can also cause hypermagnesemia. Magnesium levels may rise temporarily from an overdose of a magnesium containing medication, like laxatives or antacids, or due to blood or muscle cell destruction that liberates a large amount of intracellular magnesium into the blood. Hypermagnesemia is less common in dogs than magnesium deficiency, but when it does occur, it can be associated with life-threatening problems. Administration of IV fluids and other electrolytes can correct the immediate symptoms, however, dogs with kidney failure or heart failure still often end up being euthanized.
About 1% of the magnesium in the body circulates in the blood as a positive ion. Magnesium works in combination with other electrolytes to manage many cellular processes. Excess magnesium, called hypermagnesemia, upsets the normal balance between ions and causes serious life-threatening symptoms.
Excess Magnesium in the Blood Average Cost
From 49 quotes ranging from $500 – $5,000
High Magnesium (Hypermagnesemia): Dietary Sources, Causes, Symptoms, Treatment
A single dose toxicity study of magnesium sulfate by intravenous administration was conducted in rats and dogs. The results are summarized in the following. Magnesium sulfate was administered once at dose levels of 90, 130, 200, 300 and 450 mg/kg to Crj:CD(SD) rats at 6 weeks of age. Deaths occurred in the 200 mg/kg and above groups in both sexes. The LD50 values were 206 mg/kg for males and 174 mg/kg for females. In the surviving animals, in the 130 mg/kg and above groups, tonic convulsions, abnormal gait and tachypnea were seen. However, these signs disappeared gradually and all animals returned to a normal state by 15 min after dosing. There were no treatment-related changes in the body weight or gross pathology. Magnesium sulfate was infused for 6 hr at dose levels of 75, 300 and 1200 mg/kg (12.5, 50 and 200 mg/kg/hr) to female beagle dogs at 6 months of age. No deaths were observed in any of the dose groups and it was considered that the lethal dose level would be higher than 1200 mg/kg(200 mg/kg/hr). In the 1200 mg/kg group, vomiting, decreased spontaneous movement, staggering gait, prone position and flush of the conjunctiva and ear auricles were seen. However, these signs disappeared gradually and animals returned to a normal state by 1 hr after dosing. There were no treatment-related changes in the body weight, food consumption or gross pathology.