Nursing care
Hyperglycemia 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
Hyperglycemia nursing care starts with recognising the three Ps — polyuria, polydipsia, polyphagia — then finding what caused the rise, since the number alone doesn't tell you whether it was a missed insulin dose, an infection, or a steroid course. Priority actions are airway and hydration status, blood glucose confirmation, and identifying the trigger before treating the trigger's effect.
Recognising it at the bedside
Polyuria, polydipsia and polyphagia are the classic triad, and they appear in that order for a reason: glucose spilling into urine drags water with it osmotically, the resulting fluid loss triggers thirst, and cells starved of usable glucose signal hunger even as blood glucose climbs. A patient who has been up all night urinating and drinking water by the litre is telling you their glucose has likely been elevated for hours, not minutes.
Beyond the triad, look for blurred vision from lens swelling, fatigue, and skin that is warm and dry rather than cool and clammy, which helps distinguish hyperglycemia from hypoglycemia at a glance when a glucometer isn't immediately at hand. In more advanced presentations, fruity-smelling breath and Kussmaul respirations point toward diabetic ketoacidosis, and altered mental status with very high glucose and minimal ketones points toward hyperosmolar hyperglycemic state instead.
Why the classic presentation misleads
The three Ps describe the symptoms, but they say nothing about why the glucose rose, and that omission is where nursing judgment earns its keep. Two patients can present with an identical glucose reading of 380 mg/dL and need entirely different nursing plans: one missed their evening insulin dose after a busy shift, the other has a urinary tract infection driving stress hormones up regardless of insulin adherence, and a third is on a new prednisone taper for a flare of their rheumatoid arthritis.
Treating the number without identifying the source means the glucose will climb again as soon as the correction dose wears off. A missed dose calls for teaching and dose-timing review. An infection calls for a fever workup, urinalysis, and possibly blood cultures alongside glucose correction. A steroid course calls for anticipatory dose adjustment for the duration of the taper, not a one-off correction. The nursing action is the source, not the number, and history-taking is how you find it.
Priority nursing actions
Confirm the reading with a point-of-care glucose check rather than acting on a reported number, and assess airway, breathing, and level of consciousness first, particularly if ketones or altered mentation are present. Establish IV access early; a patient who has been vomiting or breathing rapidly from ketoacidosis is often significantly volume-depleted before any lab result confirms it.
Isotonic IV fluids typically come before insulin in DKA management, because correcting volume first helps prevent a precipitous drop in serum osmolality and reduces the risk of cerebral edema, especially in paediatric patients. Insulin, when ordered, is usually given as a continuous IV infusion in acute hyperglycemic crisis rather than subcutaneous dosing, with hourly glucose monitoring to titrate the rate. Potassium must be checked before insulin starts, since insulin drives potassium intracellularly and can precipitate dangerous hypokalemia in a patient who was already borderline.
Labs and diagnostics to expect
Serum glucose confirms the crisis, but a basic metabolic panel tells you the rest of the story: sodium (often falsely low from osmotic dilution, correctable with a formula), potassium (the number to watch before and during insulin therapy), and bicarbonate, which falls as ketoacidosis develops. Arterial or venous blood gas shows the metabolic acidosis in DKA, with a pH typically below 7.3 and bicarbonate below 18 mEq/L.
Serum and urine ketones distinguish DKA from HHS; DKA shows significant ketosis while HHS characteristically does not, despite glucose readings that can exceed 600 mg/dL in HHS. Anion gap is calculated to track resolution of the acidosis over the admission, and HbA1c, drawn once the acute picture stabilises, tells you whether this was a new diagnosis or a chronic control problem that finally decompensated.
Complications and their early signs
Cerebral edema is the complication to fear most in paediatric DKA, and it can develop hours into treatment even as glucose numbers improve — headache, sudden bradycardia, rising blood pressure, or a change in behaviour after initial improvement are red flags that warrant immediate reassessment rather than reassurance that the treatment is working.
Hypokalemia from insulin therapy can precipitate cardiac dysrhythmias, so continuous cardiac monitoring alongside potassium checks is standard in acute management. Cerebral dehydration in HHS, given the extreme osmolality involved, carries its own risk of thrombosis, so some protocols include prophylactic anticoagulation. Watch, too, for hypoglycemia overshoot as glucose corrects faster than expected, particularly once dextrose is added to IV fluids as glucose approaches the 200s.
Teaching that changes outcomes
Sick-day rules are the single piece of teaching most likely to prevent a repeat admission: continue insulin even when not eating normally, check glucose and ketones more frequently during illness, and know when ketones mean an emergency department visit rather than a phone call. Patients on steroids need explicit teaching that their insulin needs will rise for the duration of the course and should be told in advance, not discovered at the next hyperglycemic episode.
Review injection sites and timing with any patient who reports a missed dose, since lipohypertrophy from repeated injections in the same spot can cause erratic absorption that looks like non-adherence but isn't. For a patient recovering from DKA or HHS, teaching should also cover the specific trigger identified during this admission, whether that was an infection, a medication, or a gap in insulin supply, because generic diabetes teaching without addressing the actual cause leaves the door open for a repeat.
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
What blood glucose level is considered a hyperglycemic emergency?
There's no single cutoff that defines an emergency on its own; a glucose over 250 mg/dL with significant ketosis and acidosis points to DKA, while a glucose often above 600 mg/dL with minimal ketosis and altered mental status points to HHS. Clinical presentation and blood gas or ketone results matter more than the glucose number alone.
Why do you give fluids before insulin in DKA?
Rehydration improves tissue perfusion and helps lower glucose somewhat on its own, and it reduces the risk of a rapid osmotic shift once insulin starts working. Giving insulin into a volume-depleted patient without fluids first raises the risk of cerebral edema, particularly in children.
Why does potassium need checking before starting an insulin drip?
Insulin shifts potassium from the serum into cells, which can drop an already-low or borderline potassium to a dangerous level and trigger dysrhythmias. If potassium is below the normal range, potassium replacement typically starts before or alongside the insulin infusion, not after.
How is DKA different from HHS on the NCLEX?
DKA presents with significant ketones, a low pH and bicarbonate, and often affects patients with type 1 diabetes, sometimes as their first presentation. HHS presents with extremely high glucose, minimal ketones, near-normal pH, and more often affects older patients with type 2 diabetes who have a precipitating illness.