What is the difference between Hyperosmolar Hyperglycemic Nonketotic (HHNK) syndrome and Diabetic Ketoacidosis (DKA)?

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Last updated: February 25, 2025View editorial policy

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From the Research

Hyperosmolar hyperglycemic nonketotic syndrome (HHNS) and diabetic ketoacidosis (DKA) are distinct complications of diabetes, with HHNS characterized by extreme hyperglycemia, severe dehydration, and hyperosmolarity without significant ketosis, whereas DKA presents with hyperglycemia, ketosis, and metabolic acidosis. The primary difference between the two conditions lies in the presence of ketosis and the level of insulin deficiency. HHNS typically occurs in type 2 diabetes, where there is enough insulin to prevent ketone formation but not enough to control blood glucose, whereas DKA, more common in type 1 diabetes, results from severe insulin deficiency leading to ketone production and acidosis 1.

Key differences between HHNS and DKA

  • HHNS: extreme hyperglycemia (often >600 mg/dL), severe dehydration, and hyperosmolarity without significant ketosis
  • DKA: hyperglycemia (typically 300-500 mg/dL), ketosis, and metabolic acidosis
  • HHNS develops more slowly (days to weeks) compared to DKA (hours to days)
  • HHNS has a higher mortality rate due to advanced age and comorbidities of affected patients

Treatment approaches

Treatment for both conditions involves fluid resuscitation, insulin therapy, and electrolyte management, but DKA requires more aggressive insulin administration to address ketosis 2. It is essential to identify and treat the underlying precipitating cause, as well as to provide close monitoring to adjust therapy and identify complications 1.

Recent guidelines and recommendations

Recent studies emphasize the importance of timely identification and treatment of DKA and HHNS, as well as the need for careful monitoring and management of electrolytes, fluids, and insulin therapy 3, 4. The use of sodium-glucose cotransporter-2 inhibitors has been associated with an increased risk of DKA and euglycemic DKA, highlighting the need for careful consideration of medication side effects in patients with diabetes 1.

Clinical implications

In clinical practice, it is crucial to recognize the distinct characteristics of HHNS and DKA, as well as the importance of prompt and aggressive treatment to prevent morbidity and mortality. By understanding the differences between these two conditions and providing evidence-based care, clinicians can improve outcomes for patients with diabetes and reduce the risk of complications 5, 1.

References

Research

Diabetic Ketoacidosis: Evaluation and Treatment.

American family physician, 2024

Research

Management of diabetic ketoacidosis.

European journal of internal medicine, 2023

Research

Management of Diabetic Ketoacidosis in Adults: A Narrative Review.

Saudi journal of medicine & medical sciences, 2020

Research

Management of diabetic ketoacidosis in special populations.

Diabetes research and clinical practice, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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