1.  Determination of whether a patient has type 1 or type 2 diabetes is based mainly on clinical assessment rather than clear cut lab tests that will be back in time.


2.  If unsure, it is always safest to treat with insulin.


3.  Decisions regarding admission should depend on the type of suspected diabetes, the patient’s other comorbidities and the nature of follow-up that can be arranged.



Case example:

You are asked to see a 42 yr old female who presented to the ER with polyuria, polydipsia and fatigue. Her glucose on arrival was 32.1 mmol/L.  She has no prior history of diabetes and no other significant comorbidities.  What would you look for on assessment?  Would you admit this patient?


Diagnostic Criteria

• see section on diagnosis



• see sections on new diagnosis on the ward, OAHAs, insulin initiation and DKA/HHS


It is important to determine whether the patient has type 1 or type 2 diabetes.  If type 1 diabetes, the patient should generally be admitted to learn how to use insulin (unless you are 100% sure you can arrange outpatient follow-up with an endocrinologist or internist to learn within the next 12-24 hours). 


If type 2 diabetes, once the acute hyperglycemia is treated, it is possible to discharge from the emergency room if the patient is stable and follow-up can be arranged.  If so, remember that metformin will take a few weeks to work and consider using metformin together with an insulin secretagogue.  See section on hyperglycemia on oral agents for details.


If not sure (and many times it is not clear), it is always safest to error on the side of caution and admit.






Favors type 1 diabetes:

• tends to be more rapid onset

• family history of type 1 diabetes

• personal, family history or exam features of autoimmunity (thyroid disease, Addison’s, lupus, RA, IBD, celiac, etc.)

• while type 1 diabetes typically appears in the young, an older age DOES NOT rule out type 1 diabetes

• obesity does NOT rule out type 1 diabetes


Favors type 2 diabetes:

• tends to be insidious

• family history of type 2 diabetes

• personal history of gestational diabetes, PCOS

• ethnicity

• exam features of insulin resistance: acanthosis nigricans, central obesity, signs of PCOS

• while typically appears in adults, onset of diabetes in children/young DOES NOT RULE OUT type 2 diabetes

• slim patients can still have type 2 diabetes



• glucose and A1C, while useful tests to monitor diabetes, are generally not helpful to determine if a patient has type 1 or 2 diabetes

• presence of DKA (see section on hyperglycemic emergencies is typical of type 1 diabetes, but can also occur in type 2 diabetes

• insulin, C-peptide levels:  in the setting of hyperglycemia, these levels (if you can get them back on time) may not be predictive:

   - you would expect insulin and C-peptide to be LOW in type 1 diabetes.  However, in cases of prolonged hyperglycemia, regardless of cause, hyperglycemia by itself can stunt insulin secretion.  This is called GLUCOTOXICITY.  Thus, insulin and C-peptide levels could be low in type 1 or type 2 diabetes in this acute phase.

   - while insulin and C-peptide levels should not be low in type 2 diabetes, they may also not be low in the early stages of type 1 diabetes (i.e. a time when insulin secretion may be decreased, but not low).

• antibody tests like anti-GAD or anti-islet cell antibodies can be helpful, but realistically take weeks to get back.  While it can provide useful information weeks later, you won’t get the information in time.




• if unsure, it is always safest to admit

• CONSIDER discharge if:

     - the patient is hemodynamically stable and glucose has stabilized with treatment in the ER/ward

     - the diagnosis is type 2 diabetes

     - the patient can tolerate oral medications

     - follow-up can be arranged (e.g. with a primary care physician or specialist) within days

     - the patient is reliable and close to an acute care centre if needed



• consult nutritionist for diabetes diet education

• arrange for Diabetes Nurse Educator to see patient, particularly if patient is started on insulin (remember to give >24 hrs notice)

• arrange diabetes f/u for patient (either with family physician or endocrinologist, keeping in mind that average wait time to see endocrinologist is ~ 6 months)

• don’t forget to prescribe MedicAlert bracelet


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