By Wendy C. Brooks, DVM, DipABVP
Educational Director, VeterinaryPartner.com
Ketoacidosis is one of the most extreme complications of diabetes mellitus that can be experienced. Unfortunately, most cases of ketoacidosis are in patients that were not previously known to be diabetic so the owner (and pet) must deal with two serious diagnoses: one acutely life-threatening and expensive and the other requiring on-going commitment and daily treatment.
Ketoacidosis represents an extreme metabolic derangement. Stress of some sort, usually some kind of inflammatory condition such as infection or pancreatitis, creates a severe loss of glucose regulation in a patient that is already diabetic. The patient with diabetic ketoacidosis goes into an extreme fat-burning state that produces a biochemical called a ketone body. Ketone bodies can be used as an energy source for the brain when glucose is not available. (Remember that without insulin, all the glucose in the bloodstream is unavailable to the body and the tissues are starving for glucose.) The problem is that ketone bodies do not "burn clean" so that when they are in use, pH and electrolyte imbalances ensue. These imbalances created dehydration, which in turn creates more pH and electrolyte imbalances. A metabolic disaster results.
Most patients in diabetic ketoacidosis are lethargic, depressed, and will not eat. They are dehydrated and frequently nauseated. Blood glucoses are extremely high and ketones can be detected in the urine. The goal is to gradually correct all the imbalances, get the patient out of the extreme fat-burning state, and establish some sort of initial regulation of the diabetes.
Prognosis is generally fair as long as the complicating disease (the disease that is happening on top of the diabetes mellitus) can be resolved. The problem is usually the expense of round-the-clock monitoring and checking electrolytes and blood sugars so that alterations are not dangerously rapid. Ketoacidosis involves potential disasters in potassium, phosphorus, pH, blood sugar, and sodium. All of these parameters must be controlled. The goal is to convert the complicated diabetic patient into an uncomplicated diabetic patient, but the patient will still be diabetic at the end of treatment.
What to Expect in the Hospital
The sooner the crisis is recognized, the faster treatment can be started. Because electrolytes can change moment by moment, blood testing is necessary throughout the day to keep track and keep the imbalances corrected. A facility that offers 24-hour care is ideal. Aside from the monitoring required to manage the ketoacidosis, testing to determine the precipitating stress is necessary as well.
In dogs, the most common precipitating/concurrent conditions are: pancreatitis, urinary tract infection, and Cushing's disease. In cats, precipitating/concurrent conditions include: hepatic lipidosis, kidney infection, pancreatitis, and cholangiohepatitis.
Fluid therapy is the key to treatment. The patient is invariably dehydrated from the high circulating blood sugar levels, which cause excess fluid loss in urine, as well as from vomiting and/or diarrhea, which are common in ketoacidosis. Aside from simply providing fluids, the IV fluid provides a vehicle by which other metabolic derangements can be repaired.
Blood sugar must be controlled if treatment is to be successful but to prevent brain damage, blood sugar levels must be dropped slowly. To achieve this, “regular insulin” (typically Humulin R®) is used, given either as multiple intramuscular injections or as a continuous drip. This type of insulin is short acting and wears off quickly, which allows it to provide small adjustments. It is not until the patient is eating and nausea has been controlled that maintenance insulins can be started.
Patients in ketoacidosis are greatly depleted in potassium. While insulin is needed to control blood sugar, insulin makes the problem worse by driving potassium into the body’s cells and out of the bloodstream. Typically, high amounts of potassium must be supplemented in the intravenous fluid solution.
Low levels of phosphorus also accompany diabetic ketoacidosis and if levels drop too low, the patient’s red blood cells will begin to burst and be unable to maintain integrity. Phosphorus is also supplemented through the intravenous fluid solution.
The term ketoacidosis implies that the blood pH is overly acidic. If the situation is severe enough, sodium bicarbonate must be added to the intravenous therapy.
All these aspects require regular monitoring, which means lab work perhaps four times daily or more. Patients in diabetic ketoacidosis require close monitoring and intensive care.
When urine dipsticks no longer test positive for ketones and the patient is eating well and in good spirits, he or she is able to go home and be managed as a regular diabetic. Diet, monitoring, insulin etc. will be on-going concerns. Ideally, Ketostix, obtainable from any drug store, will be used at home to monitor for ketones to head off problems before they become extreme in the future.