NUR5203 Module 3 comparative pathophysiology analysis example

Both Sugars Were Over 500: Separating Diabetic Ketoacidosis From the Hyperglycemic Hyperosmolar State by Mechanism, in Two Patients Admitted the Same Night

Student Name

American College of Education

NUR5203: Advanced Pathophysiology and Health Assessment

Module 3 Assignment

Instructor Name

January 25, 2028

Two Patients

The first patient, a composite 24-year-old man with type 1 diabetes, stopped taking insulin two days earlier after losing his job and his insurance. He arrived vomiting, with abdominal pain, deep rapid breathing and a fruity odor on his breath. He was alert but exhausted. His glucose was 512 mg/dL, arterial pH 7.14, bicarbonate 9 mmol/L, anion gap 26 and serum beta-hydroxybutyrate 6.8 mmol/L.

The second patient, a composite 79-year-old woman with type 2 diabetes treated with oral medication, came from an assisted living facility where staff noticed she had become drowsy and confused over five days. She had a urinary tract infection and had been drinking little. Her mucous membranes were dry, her blood pressure was 96/58 mm Hg and she responded only to her name. Her glucose was 1,040 mg/dL, pH 7.36, bicarbonate 22 mmol/L, beta-hydroxybutyrate 0.9 mmol/L and calculated effective serum osmolality 352 mOsm/kg.

Both had severe hyperglycemia, both were dehydrated and both were admitted as hyperglycemic crises. The nursing students on the unit were told one had DKA and the other HHS, and several asked why two people with high sugar needed such different monitoring. That question is the purpose of this analysis.

The Shared Starting Point

Both crises begin with too little insulin action relative to the body's needs, combined with a rise in the counterregulatory hormones glucagon, cortisol, catecholamines and growth hormone, usually triggered by an illness, infection or missed treatment (Umpierrez et al., 2024). Without enough insulin, muscle and fat take up less glucose, and the liver produces more through gluconeogenesis and glycogen breakdown. Blood glucose rises. Once it exceeds the kidney's ability to reabsorb glucose, glucose spills into the urine and pulls water with it, an osmotic diuresis that causes large losses of water, sodium and potassium. Both patients' dehydration, and the older patient's low blood pressure, come from this shared pathway.

The One Difference: How Much Insulin Remains

The conditions part ways over fat. Insulin normally restrains lipolysis, the breakdown of stored fat into free fatty acids, and it takes much less insulin to hold back lipolysis than to move glucose into cells. In DKA, insulin is almost completely absent. Lipolysis runs unchecked, the liver converts the flood of free fatty acids into ketone bodies under the influence of glucagon, and the ketoacids beta-hydroxybutyrate and acetoacetate accumulate faster than they can be used or excreted. Their hydrogen ions consume bicarbonate, producing a metabolic acidosis with a raised anion gap.

In HHS, some insulin remains, usually enough to restrain lipolysis and ketone production but not enough to control glucose. Without the acidosis that brings a patient with DKA to care within a day or two, hyperglycemia and osmotic diuresis can continue for days. Glucose climbs higher, fluid losses grow larger and the blood becomes more concentrated. Kitabchi et al. (2009) estimated typical total water deficits of about 6 L in DKA and about 9 L in HHS. One patient was poisoned by acid; the other was drying out slowly, and the difference was a small amount of insulin still working in her liver.

Each Finding Traced to Its Cause

The young man's deep, rapid breathing is Kussmaul respiration, the respiratory system's compensation for metabolic acidosis: exhaling more carbon dioxide raises pH. His fruity breath is acetone, a ketone exhaled through the lungs. His abdominal pain and vomiting are common in DKA and are associated with the severity of acidosis, and the vomiting worsens his fluid losses. His alertness despite a pH of 7.14 reflects a serum osmolality that, though raised, is lower than in HHS.

The older woman's drowsiness and confusion reflect hyperosmolality. As the blood becomes concentrated, water moves out of brain cells, and mental status tracks effective osmolality closely; a patient with a markedly altered level of consciousness but only modest hyperosmolality should prompt a search for another cause. Her low blood pressure reflects a larger fluid deficit accumulated over days. Her normal breathing pattern, normal pH and low beta-hydroxybutyrate reflect the absence of significant ketosis.

The laboratory values confirm the separation. Current consensus criteria define DKA by hyperglycemia or known diabetes together with ketonemia and metabolic acidosis, and HHS by marked hyperglycemia and hyperosmolality without significant ketonemia or acidosis, while recognizing that some patients have features of both (Umpierrez et al., 2024). The young man meets the first description and the older woman the second.

Why the Monitoring Differs

The mechanisms explain the students' question about monitoring. In DKA, the danger lies in acidosis and in potassium: insulin treatment drives potassium into cells, and a patient whose total body potassium is depleted can become dangerously hypokalemic as treatment begins. Nurses therefore watch the anion gap or ketone levels to judge resolution and check potassium frequently. In HHS, the danger lies in dehydration and in the brain. Fluid replacement is the core of treatment, and because a rapid fall in osmolality can shift water back into brain cells, nurses monitor osmolality, sodium and neurological status closely, along with signs of fluid overload in an older patient whose heart may not tolerate large volumes. Thrombosis risk is also higher in HHS because of the concentrated blood and immobility.

When the Glucose Misleads

The mechanism also explains a trap that students will meet. Because ketoacidosis depends on the lack of insulin's effect on fat, not on the glucose level itself, it can occur with a glucose that looks only modestly raised. Peters et al. (2015) described 13 episodes of ketoacidosis or ketosis in nine patients taking sodium-glucose cotransporter 2 inhibitors, drugs that lower glucose by making the kidneys excrete it. Because these patients' glucose values were not strikingly high, both they and their clinicians were slow to recognize that they were acidotic, and the authors urged that patients taking these drugs who develop nausea, vomiting or malaise be checked for acidosis whatever their glucose. For teaching, the lesson is that a student who has learned DKA as very high sugar will miss it, while a student who has learned it as fat breakdown without enough insulin to stop it will ask the right question: what is the bicarbonate, and are there ketones? The consensus criteria reflect this, since they no longer require a high glucose when a patient is known to have diabetes. The same reasoning helps with patients who fall between the two conditions, with high osmolality and some ketosis, which the students on the unit also saw that month.

Teaching the Comparison

For prelicensure students, the author uses a single organizing question in post-conference: how much insulin is left? Students then predict, from that answer alone, the speed of onset, the presence of ketones and acidosis, the size of the fluid deficit, the mental status and the monitoring priorities, and check their predictions against the two cases. The exercise works because every difference between the conditions follows from that one question, which is the point of teaching by mechanism. Students who can answer it can also reason about the overlap cases and about ketoacidosis with near-normal glucose, which they will meet later in practice.

References

Kitabchi, A. E., Umpierrez, G. E., Miles, J. M., & Fisher, J. N. (2009). Hyperglycemic crises in adult patients with diabetes. Diabetes Care, 32(7), 1335-1343. https://doi.org/10.2337/dc09-9032

Peters, A. L., Buschur, E. O., Buse, J. B., Cohan, P., Diner, J. C., & Hirsch, I. B. (2015). Euglycemic diabetic ketoacidosis: A potential complication of treatment with sodium-glucose cotransporter 2 inhibition. Diabetes Care, 38(9), 1687-1693. https://doi.org/10.2337/dc15-0843

Umpierrez, G. E., Davis, G. M., ElSayed, N. A., Fadini, G. P., Galindo, R. J., Hirsch, I. B., Klonoff, D. C., McCoy, R. G., Misra, S., Gabbay, R. A., Bannuru, R. R., & Dhatariya, K. K. (2024). Hyperglycemic crises in adults with diabetes: A consensus report. Diabetes Care, 47(8), 1257-1275. https://doi.org/10.2337/dci24-0032