Nursing care
Hyperosmolar Hyperglycemic State nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
Hyperosmolar hyperglycemic state features glucose often above 600 mg/dL with little or no ketosis, because residual insulin blocks ketogenesis but not the rising glucose. It develops gradually, usually in older adults with type 2 diabetes, and dehydration and neurological changes dominate the picture. Fluids, careful glucose correction, and neuro checks are the priorities.
Recognising it at the bedside
HHS typically develops over days rather than hours, in an older adult with type 2 diabetes, often triggered by infection, a missed medication, or an acute illness like a stroke or myocardial infarction that reduces fluid intake. Glucose is markedly elevated, frequently above 600 mg/dL and sometimes over 1000 mg/dL, far higher than the levels typically seen in DKA.
The dominant clinical picture is profound dehydration and neurological change rather than the respiratory and gastrointestinal symptoms of DKA. Expect altered mental status ranging from confusion to coma, correlating roughly with the degree of serum osmolality. Skin turgor is poor, mucous membranes are dry, and hypotension with tachycardia reflects severe volume depletion that has built up gradually as the patient's thirst response failed to keep pace with osmotic diuresis.
Why the classic presentation misleads
Nurses trained to look for Kussmaul respirations and fruity breath in hyperglycaemic emergencies can miss HHS, because neither is typically present. There is just enough circulating insulin to suppress lipolysis and ketogenesis, but not enough to move glucose into cells effectively, so the patient develops extreme hyperglycaemia without the acidosis that drives DKA's respiratory pattern.
The absence of vomiting and abdominal pain, both common in DKA, means patients and families often do not seek care until neurological symptoms are advanced. An older adult presenting with new confusion, lethargy, or even focal deficits resembling a stroke should prompt a glucose check, because HHS is frequently misread as a primary neurological event until the glucose result returns. This slower, quieter onset is why HHS carries a higher mortality rate than DKA despite less dramatic biochemistry.
Priority nursing actions
Fluid resuscitation is the first and most urgent action, addressing volume deficits that in HHS are often larger than in DKA, sometimes 8 to 10 litres. Isotonic saline is given aggressively in the first hours, with the rate adjusted for cardiac and renal status, since many HHS patients are older adults with comorbidities that limit how fast fluid can be given safely.
Insulin is started after fluid resuscitation is underway, at a lower rate than typically used in DKA, because glucose in HHS tends to fall quickly with fluids alone and a fast insulin-driven drop increases the risk of cerebral oedema and hypotension. Continuous neurological assessment matters throughout, since mental status is both the presenting sign and the marker nurses use to judge whether treatment is correcting the underlying osmolality.
Labs and diagnostics to expect
Expect a basic metabolic panel showing severe hyperglycaemia, elevated blood urea nitrogen and creatinine reflecting prerenal injury from dehydration, and a serum osmolality typically above 320 mOsm/kg. Ketones are absent or only mildly present, and the anion gap is normal or only mildly elevated, distinguishing HHS from DKA on the same panel.
Sodium is often falsely low due to the osmotic pull of glucose and should be corrected using a calculated formula before it is interpreted. Potassium may be normal or elevated at presentation despite total-body depletion, for the same intracellular shift seen in DKA, and needs the same proactive monitoring once insulin starts. A complete blood count and cultures are drawn to identify the infection or acute illness that commonly precipitates HHS.
Complications and their early signs
Cerebral oedema, arterial and venous thromboembolism, and cardiovascular collapse are the complications that make HHS higher-risk than DKA. The profound hyperosmolar state increases blood viscosity, raising the risk of deep vein thrombosis and stroke, so prophylactic anticoagulation is considered early in the admission unless contraindicated.
Watch for a mental status that worsens rather than improves as glucose corrects, which suggests cerebral oedema from too-rapid osmotic shift rather than ongoing hyperglycaemia. Hypokalaemia from insulin-driven cellular shift remains a risk throughout treatment and can precipitate arrhythmia if unmonitored. Acute kidney injury from prolonged dehydration should be tracked with hourly urine output and serial renal function tests until fluid status stabilises.
Teaching that changes outcomes
Most HHS admissions trace back to an illness, infection, or medication change that reduced fluid intake in a patient who did not recognise the early signs of rising glucose. Teach patients and caregivers, especially those managing an older relative's type 2 diabetes, to check glucose more frequently during any illness and to maintain fluid intake even when appetite is poor.
Emphasise the symptoms that warrant urgent evaluation: new confusion, unusual drowsiness, or reduced urine output in someone with known diabetes. Because HHS often occurs in patients with limited insulin reserve who may not realise their diabetes has progressed, discharge teaching should cover medication adherence, the sick-day management plan, and who in the household can recognise a change in mental status early.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our endocrine practice questions are the closest set to what this page covers.
Common questions
Why doesn't HHS cause ketosis like DKA does?
In HHS, enough endogenous insulin remains in circulation to suppress lipolysis and ketogenesis, even though it isn't enough to control glucose uptake into cells. This is why glucose climbs to extreme levels without the ketone production and acidosis seen in DKA.
What glucose level is typical in HHS compared with DKA?
HHS commonly presents with glucose above 600 mg/dL and sometimes over 1000 mg/dL, notably higher than the typical DKA threshold of around 250 to 300 mg/dL. The higher glucose reflects days of unchecked hyperglycaemia rather than the acute onset seen in DKA.
Why is fluid resuscitation given before insulin in HHS?
Volume deficits in HHS are often larger than in DKA, and fluids alone begin correcting glucose by improving renal perfusion and dilution. Starting insulin before adequate fluid replacement risks a sharp glucose drop and hypotension in a patient who is often older and haemodynamically fragile.
Why is HHS more dangerous than DKA despite milder biochemistry?
HHS typically affects older adults with more comorbidities, develops more slowly so it's often diagnosed later, and carries a higher risk of thromboembolism and cardiovascular collapse from severe hyperosmolality. Mortality rates for HHS exceed those of DKA even though the acid-base picture is less dramatic.
How is the sodium level interpreted in HHS?
Measured serum sodium is often falsely low because high glucose osmotically pulls water into the vascular space. Nurses and providers use a corrected sodium calculation, adjusting for the glucose level, before deciding whether the patient is truly hyponatraemic.