Diabetes mellitus (main)

Background

• Growing in worldwide prevalence
• Results from either inability of the body to release insulin from the pancreas or a resistance against the actions of insulin

Clinical Features

• Patients with diabetes may be asymptomatic
• Acute symptoms range from those of nonketotic hyperglycemia (e.g. polyuria, polydipsia) to DKA (ill appearance, acetone breath, Kussmaul's breathing, somnolence)

Differential Diagnosis

Hyperglycemia

Diabetic Emergencies

• Diabetic ketoacidosis (DKA)
• Diabetic ketoacidosis (peds)
• Hyperosmolar hyperglycemic state (HHS)
• Nonketotic hyperglycemia
• Euglycemic DKA (SGLT-2 inhibitors, pregnancy, fasting)

Diabetes Mellitus (New or Known)

• Type 1 diabetes mellitus (new-onset or uncontrolled)
• Type 2 diabetes mellitus (new-onset or uncontrolled)
• Medication noncompliance or insulin pump malfunction
• Gestational diabetes
• Latent autoimmune diabetes of adults (LADA)

Medication/Drug-Induced

• Corticosteroids (most common drug-induced cause)
• Thiazide diuretics
• Atypical antipsychotics (olanzapine, clozapine, quetiapine)
• Beta-blockers (especially non-selective)
• Phenytoin
• Tacrolimus, cyclosporine (transplant patients)
• Protease inhibitors (HIV antiretrovirals)
• Catecholamines (epinephrine, norepinephrine infusions)
• SGLT-2 inhibitors (paradoxical DKA with euglycemia)
• Total parenteral nutrition (TPN)
• Dextrose-containing IV fluids (iatrogenic)
• Niacin
• Pentamidine (initially hyperglycemia, then hypoglycemia from beta-cell destruction)

Physiologic Stress Response

• Sepsis / critical illness (stress hyperglycemia — very common in the ED)
• Trauma / major surgery / burns
• Acute coronary syndrome / myocardial infarction
• Stroke (especially hemorrhagic)
• Pancreatitis (both a cause and consequence)
• Shock (any etiology)
• Pain (catecholamine surge)
• Seizure (postictal)
• Physiologic stress alone rarely causes glucose >200 mg/dL in non-diabetics; glucose >200 in a "stress response" should prompt evaluation for undiagnosed diabetes or prediabetes

Endocrine

• Cushing syndrome / Cushing disease (cortisol excess)
• Pheochromocytoma (catecholamine excess)
• Hyperthyroidism / thyroid storm
• Acromegaly (growth hormone excess)
• Glucagonoma (rare)
• Somatostatinoma (rare)

Pancreatic

• Pancreatitis (acute or chronic — destruction of islet cells)
• Pancreatic malignancy (adenocarcinoma, neuroendocrine tumors)
• Post-pancreatectomy
• Cystic fibrosis-related diabetes
• Hemochromatosis (iron deposition in pancreas — "bronze diabetes")

Toxic/Overdose

• Iron toxicity (hepatic injury → impaired glucose regulation)
• Salicylate toxicity (can cause both hyper- and hypoglycemia)
• Sympathomimetic toxicity (cocaine, methamphetamine)
• Calcium channel blocker toxicity (impairs insulin secretion)
• Carbon monoxide toxicity (stress response)

Other

• Renal failure (chronic kidney disease, acute kidney injury — impaired insulin clearance AND insulin resistance)
• Cirrhosis / hepatic failure (impaired glycogenolysis regulation)
• Pregnancy (gestational diabetes, steroid administration for fetal lung maturity)
• Parenteral nutrition (TPN, dextrose-containing fluids)
• Post-transplant diabetes (immunosuppressants)

Complications of Diabetes (Not Causes of Hyperglycemia)

These are associated conditions that may be present alongside hyperglycemia but do not themselves cause elevated glucose:

• Diabetic foot infection
• Diabetic peripheral neuropathy
• Cerebral edema in DKA
• Diabetic retinopathy
• Diabetic nephropathy

Evaluation

• Diabetes mellitus itself is not normally a diagnosis sought in the emergency department (i.e. via A1C)
• Hyperglycemia can be found on laboratory testing
  • Asymptomatic patients do not necessarily require additional testing
  • Symptomatic or potentially symptomatic patients require additional testing
    • Check CBC, BMP, and ketones (if sick, additionally see DKA workup)
    • UA is only necessary if you are ruling out urinary infection or do not have serum ketones available and are using it as a screening mechanism

Management

• There is no need to treat the glucose "number" (i.e. nonketotic hyperglycemia in the emergency setting (i.e. with insulin)
  • Higher discharge glucose levels are not associated with a greater risk of repeated ED visits, hospitalization, or other adverse outcomes.
• For hyperosmolar hyperglycemic state, DKA, or another specific process see that particular page

Type II Diabetes Outpatient Management

• 1st line: Metformin 500mg BID → 1000mg BID, do not give in people with abnormal LFT's, CHF Stage 3/4 and ARI, CKD
• 2nd Agent: Glipizide start 2.5mg BID → 5mg BID, need to monitor for hypoglycemia
• 3rd Agent: Pioglitazone
• After 3 agents: need to start insulin if not controlled
  • NPH BID or Lantus Qday (0.1 to 0.2mg/kg) and titrate to Fasting Blood Sugar

Disposition

• Asymptomatic patients or those with nonketotic hyperglycemia can be discharged with follow up with primary care physician

See Also

• Hypoglycemia
• Evidence Review Sodium Bicarbonate in DKA
• EBQ:Relevance of Discharge Glucose Levels