Short answer: Diabetic ketoacidosis has high glucose, raised ketones and acidosis. The hyperosmolar hyperglycaemic state has very high glucose and dehydration without significant ketones. Hypoglycaemia is a low glucose that needs fast sugar if the patient can swallow. Each is an emergency, and exams reward the first safe action and early escalation.
Scope and sources
The thresholds below come from the Joint British Diabetes Societies for Inpatient Care (JBDS) guidelines. Other bodies use slightly different cut-offs, and exam questions normally give the numbers you need. Always follow the current pathway at work.
This is exam-preparation revision, not clinical guidance. In practice, follow your own organisation’s policies and the current guideline, and check doses and thresholds against them.
Diabetic ketoacidosis (DKA)
The JBDS adult pathway (March 2023) names three features together: capillary glucose above 11 mmol/L or known diabetes, ketones above 3 mmol/L (or urine ketones at two plus or more), and venous pH below 7.3 or bicarbonate below 15 mmol/L. An international consensus report has been reported to use a bicarbonate cut-off of 18, so read the numbers in the question.
Typical picture: thirst, passing a lot of urine, abdominal pain, vomiting, fast deep breathing, a fruity smell on the breath and drowsiness. Core treatment in the pathway is intravenous fluids and a fixed-rate intravenous insulin infusion, with potassium monitored and replaced as the pathway says. Doses vary, so use the pathway, not memory.
Hyperosmolar hyperglycaemic state (HHS)
HHS develops over days, mostly in older people with type 2 diabetes. Features often used to separate it from DKA are glucose of about 30 mmol/L or more, ketones low or absent, pH of 7.3 or more and serum osmolality of about 320 mOsm/kg or more. The JBDS 2022 guideline notes that definitions are not rigid, so treat these as differentiating features.
The patient is often very dehydrated and drowsy. Fluid replacement is central, with careful monitoring of sodium, osmolality and the rate of change. These patients are at risk of thrombosis and foot problems, so exam questions may add preventive care.
Hypoglycaemia
JBDS inpatient guidance treats a glucose below 4.0 mmol/L in a person with diabetes as hypoglycaemia needing action. For a patient who is conscious and can swallow, the guidance uses 15 to 20 g of quick-acting carbohydrate, such as glucose tablets or juice, then rechecks the glucose. For a patient who cannot swallow or is unconscious, the route is intravenous glucose or intramuscular glucagon under your protocol, with airway protection.
Signs: sweating, shakiness, hunger, confusion, odd behaviour, reduced consciousness. Always check the glucose before treating when it is safe to do so. After recovery, give a longer-acting carbohydrate if the protocol says to, find the cause and document it.
Quick comparison
Learn this as a table in your head.
- Onset: DKA over hours, HHS over days, hypoglycaemia over minutes.
- Glucose: DKA high, HHS very high, hypoglycaemia low.
- Ketones: DKA raised, HHS low or absent, hypoglycaemia not the issue.
- Breathing: DKA fast and deep, HHS usually not, hypoglycaemia normal.
- First step: DKA and HHS, ABCDE, access, fluids and escalation. Hypoglycaemia, fast sugar or the route your protocol gives.
How exams test it
Common patterns: a drowsy patient with a low glucose, where the safe order is check, treat and recheck. A patient with vomiting and fast breathing, where you think DKA and escalate. A patient who stops eating but wants to take usual insulin, where you ask for medical advice rather than just stopping insulin. Practise the gas side in blood gas interpretation and the safety side in the medication safety guide. Insulin is a high-alert drug, see high-alert medications.
Monitoring and what to document
In all three emergencies, exams reward monitoring and documentation as much as the first action. Record glucose, ketones if used, observations, fluid balance and conscious level at the intervals in the pathway. Watch potassium, because it can fall during treatment of DKA. Document the time of the first glucose, the treatment given and the repeat result. Review the cause with the team, such as a missed dose, infection, a new drug or reduced eating, and plan teaching so the patient knows sick-day rules and when to seek help.
Frequently asked questions
This article is general educational guidance, not official advice. Exam rules, fees and timelines are set by the Dubai Health Authority and the test provider and can change, so always confirm the latest details on their official channels.
Last updated .