Diabetes - Medical Student Cheat Sheet

This student "cheat sheet" is designed to provide medical students with basic information regarding the diagnosis and treatment of type 2 DM. It includes Questions to Ask, what to look for on a Physical Exam, Labs to Order, and basic Treatment Plans.

These guides are particularly designed for first and second-year medical students as an introduction to ambulatory care medicine and attempts to tie in the basic pathophysiology that is high-yield for USMLE Step 1.

Any and all feedback is very welcomed.

1. Revised 3/6/14. Email [email protected] with any feedback.

DIABETES MELLITUS CHEAT SHEET

Diabetes Mellitus is a chronic disease where the body cannot regulate blood glucose leading to
hyperglycemia. Insulin is a peptide hormone, secreted from beta cells of the pancreas, which regulates
blood glucose. It allows glucose to enter the cells by causing them to express GLUT2 glucose receptors.

There are two types of diabetes mellitus:
DM 1 - cannot make insulin. Auto-immune. Younger patients. Weaker genetic predisposition.
DM 2 –insulin insensitivity. Older, obese, and minorities. Strong genetic predisposition.

Current criteria for diagnosis of diabetes:
Hemoglobin A1c > 6.5% OR Fasting Plasma Glucose >126 OR 2-hour Oral Glucose Tolerance Test >200
OR hyperglycemic symptoms and a random glucose >200 || Pre-diabetes criteria = A1c 5.7- 6.4

Hemoglobin A1c (glycated hemoglobin or HbA1c) is a form of hemoglobin measured to identify
average plasma glucose over a longer period of time (i.e. approximately the lifespan of a RBC: 120 days).
When glucose levels are high, glucose attaches to the hemoglobin of red blood cells, forming HbA1c.

DM2 is then monitored regular A1C readings with at home glucometers (esp. if on insulin).
Patients on insulin should check blood sugar prior to meals and snacks, occasionally 2 hours after meals,
at bedtime, prior to exercise, and when they suspect low blood glucose.
*Always ask if patient is regularly checking his / her blood sugar and about the range of values.

Review of Systems / HPI Questions to Ask:
 Polyuria / Nocturia
 Erectile dysfunction
 Peripheral neuropathy
o Decreased sensation
o “tingling” sensations in hands/feet

 Vision changes
 Nausea/Vomiting/Diarrhea
 Constipation/Bloating
 Depression/Anxiety
 Hx of UTI, infxns in vagina, nails, mouth
* Also ask about episodes of hypoglycemia (with or without symptoms of syncope, light-headedness), as this
is a serious risk of treatment.

Chronic Cx of DM: Small vessel disease: retinopathy, nephropathy, (glycosylation of endothelium)
Large vessel disease: coronary artery disease, vascular occlusive disease
Osmotic damage: neuropathy
Acute Cx of DM: Diabetic Ketoacidosis (DKA) is classically associated with Type 1 DM but can also be
found in DM2, particularly in the late stages where the pancreas has been damaged and insulin secretion
affected. Hyperosmolar Hyperglycemic State (HHS) is found in Type 2 DM.

Physical exam findings to look for:
 Acanthosis nigricans
o Dark, thick, velvety skin on neck or
axilla. Shows insulin resistance.
 Dehydration
 Decreased tactile sensitivity
 Autonomic neuropathy
o orthostatic hypotension
 Ulcers (particularly on feet)

2. Revised 3/6/14. Email [email protected] with any feedback.

Labs to Order
- Microalbumin annually
- Creatinine (iStat BMP) annually
- A1C every 3 months / every 6 months if at goal
- Lipid panel annually
Can also consider: TSH, CMP. Annual eye exam by ophthalmologist is recommended.

Treatment:
Goal A1c: <7% using a combination of lifestyle modification, oral therapy (DM2), and insulin.

LIFESTYLE MODIFICATION
Nutrition: Decrease carbohydrate intake, sugar-sweetened beverage cessation
Exercise: 150 minutes / week of moderate aerobic exercise
Education: Smoking cessation, regular foot care
Rec’d Vaccinations: Pneumococcus (one time), Influenza (annually), Hep B (if unvaccinated)

PHARMACOTHERAPY
DM1: Insulin
DM2: 1
st
line: Metformin | 2
nd
line: Add second oral agent | 3
rd
line: third oral or insulin
If urine microalbumin lab is positive, begin ACE-Inhibitor to protect from further diabetic nephropathy

DRUG EXAMPLE MECHANISM NOTE
Biguanides Metformin hepatic gluconeogenesis
C/I: kidney
dysfunction
SE: N/V/D, lactic
Acidosis (rare)
Sulfonylurea
Glipizide,
Glyburide,
Glimepiride
Insulin secretion (blocks K+ efflux -
> increased Ca+ influx -> insulin
granule release)
SE: hypoglycemia
Thiazolidinediones
(TZDs)
Pioglitazone
Activate PPAR nuclear receptors ->
 insulin sensitivity
SE: weight gain,
hepatotoxicity
*Drugs in red = available in Free Clinic. **C/I = contra-indications. SE = common side effects.

Other DM drugs to know about and their side effects:
GLP-1 analogs (Exenatide)- bloating/pancreatitis
α-glucosidase inhibitors (Acarbose)– abd. gas
DDP-4 inhibitors (Sitagliptin) – pancreatitis
SLGT2 inhibitors (canaglifozin)

Injectable Insulin (indicated for DM1 or uncontrolled DM2) – look out for hypoglycemia
TYPE EXAMPLE ONSET OF ACTION DURATION OF ACTION
Rapid Lispro, aspart, glulisine 5-15 minutes 3-6 hours
Short Regular (R)* 1-2 hours 6-10 hours
Intermediate isophane (NPH or N) 1-2 hours 10-20 hours
Long Glargine (Lantus), levemir 1-2 hours 24 hours
Mixed 70% NPH / 30% regular
* 2 brands of insulin available: Humulin and Novolin

Insulin treatments can be managed in several modalities including sliding scale, pre-prandial, and mixed.
Sliding-scale is the least effective, but most accessible for initiating treatment. “Carb counting” is a
technique that can be taught to help patients with pre-prandial insulin dosing.