(Photo contributor: Binita R. Shah, MD)
*The authors acknowledge the special contributions of Irene Mamkin, MD, and Sonal Bhandari, MD, to prior edition.
Diabetic ketoacidosis/ketoacidemia (DKA) is a life-threatening metabolic disturbance caused by an absolute or relative insulin deficiency resulting in ketone body production and decreased serum total CO2 concentration. DKA occurs most commonly in type 1 diabetic patients, but may also occur in type 2 diabetic patients.
Insulin deficiency results in hyperglycemia, glycosuria, and intracellular starvation, leading to release of counterregulatory hormones (catecholamines, glucagon, cortisol, and growth hormone). This triggers lipolysis, proteolysis, glycogenolysis, gluconeogenesis, and insulin resistance. Glycogenolysis and gluconeogenesis exacerbate the already-present hyperglycemia. A negative cycle of progressive ketoacidemia, hyperglycemia, dehydration, electrolyte losses, and possible brain swelling may result in death.
Diffuse Brain Swelling; Diabetic Ketoacidosis. A noncontrast head CT scan shows obliteration of all CSF spaces including ventricles and basal cisterns with blurring of the margins of gray and white matter, typical for diffuse cerebral edema and herniation around the brainstem. These findings were seen in a patient with new-onset diabetes who initially presented with a normal mental status, severe ketoacidemia without shock, and received isotonic saline 60 mL/kg over 2 hours. Progressively diminished arousability and hypertension were unrecognized signs of raised intracranial pressure until irregular respirations and a decrease in heart rate ensued. (Photo contributor: Geetha Chari, MD.)
Brain Swelling Seen at Autopsy; Diabetic Ketoacidosis (DKA). A dorsal view of the brain shows severe brain swelling with flattened gyri and effaced sulci. Evidence of brain swelling with herniation was seen on the brain’s ventral surface. Pretreatment brain herniation is rare, but brain swelling prior to treatment (incompletely understood cause[s]) appears common among pediatric patients with DKA. This 17-year-old known diabetes patient collapsed at home and developed hypertension, bradycardia, and agonal respirations on arrival of first responders. Such patients underscore the need for careful volume resuscitation, fluid and electrolyte management, and timely administration of insulin in those with DKA, because they likely present with some degree of brain swelling even before treatment begins. (Photo contributor: M.G.F. Gilliland, MD.)
Key findings include all or some of the following: polyuria/incontinence, polydipsia, polyphagia (inconsistent), nocturia/enuresis, varying degrees of dehydration, weight loss, abdominal pain, nausea, vomiting, hyperventilation, Kussmaul breathing (which is clinically visible and may be confused with respiratory distress from primary respiratory diseases such as pneumonia), subnormal body temperature (in severe DKA; may also occur in sepsis), altered mental status (which may be caused by shock, profound ketoacidemia, or raised intracranial pressure [ICP]), the fruity odor of ketones ...