High-Yield Diabetes – USMLE Step 2 CK exam

by / Friday, 02 July 2010 / Published in Internal Medicine

Type 1 DM

  • Autoimmune destruction of pancreatic b-cells, leads to insulin deficiency

Signs and Symptoms:

  • Polyuria, polyphagia, polydipsia
  • Weight loss
  • DKA – emergency

Diagnosis:

  • Random plasma glucose >200 with symptoms OR
  • Two measurement of fasting glucose >125
  • 2hr oral glucose tolerant test >200 with or without symptoms

Treatment:

  • Insulin replacement

Complications:

  • DKA

Signs and Symptoms of DKA:

  • Hyperglycemia >250
  • Hyperkalemia (due to transcellular shift out of the cell in exchange for H+)
  • Low pH
  • Elevated levels of acetone, acetoacetate, and b-hydroxybutyric acid
  • Increased anion gap

DKA treatment:

1st – IV fluids

2nd – potassium replacement(hyper becomes hypo as DKA is treated), insulin replacement

3rd – addition of glucose to insulin drip when pt becomes normoglycemic (keep giving insulin until ketones are gone)

** insulin is given originally to shut down ketogenesis, not decrease glucose, thus keep giving insulin until ketones are gone despite normal glucose.

Type 2 DM

  • A peripheral insulin resistance
  • Usually adult onset (changing with the obesity epidemic)
  • Family history often plays a strong role
  • Ketosis is NOT associated with DM2

Signs and Symptoms:

  • Acute – 3P’s (polydypsia, polyphagia, polyuria), fatigue, weight loss
  • Subacute – infections (yeast infections, Mucor, S. Aureus)

Chronic signs and symptoms:

  • Macrovascular – stroke, CAD
  • Microvascular – retinitis, nephritis
  • Neuropathy – parasthesia, stocking and glove burning sensation, autonomic insufficiency, decreased sensation

Diagnosis: same as type 1

Treatment:

  • FIRST treatment is always diet and lifestyle modifications
  • Oral hypoglycemics for mild/moderate disease
  • 1st line – metformin (biguanide), its MOA is blocking gluconeogenesis
  • 2nd line – sulfonylurea (glyburide), MOA is increasing b-cell insulin secretion
  • 3rd line – Thiazolidinediones (pioglitazone), MOA is increasing tissue sensitivity to insulin
  • If oral drugs don’t work, patient may require insulin
  • Lifelong cases most usually will require insulin treatment
  • ACEI’s important because they slow down the progression of diabetic nephropathy

Monitoring DM with HbA1c:

  • HbA1c allows us to get a measure of the average glucose level over the past 3 months
  • Tight glucose control is directly responsible for decreasing complications and mortality in both types of insulin
  • An HbA1c <7 or 8 is recommended (this # is always decreasing)

Complications of DM2:

Hyperosmolar Hyperglyicemic Nonketotic Coma(HHNK):

  • Often precipitated by stress, secondary to hypovolemia
  • Glucose can become >1000mg/dL
  • There is no acidosis (as in type 1 DM)

Treating HHNK:

  • IV fluids are most important, rehydration is often all that is needed.
  • May require upwards of 10L of fluids
  • Without treatment, mortality rate climbs over 50%

Complications of Diabetes

Hypertension – Control is essential in DM patients because it causes long-term complications of the heart, eye, kidney, and brain.  Goal is to keep it <130/90

Lipid Management – Goals are: LDL <100, if patient has CAD + DM, the goal is <70.

Retinopathy – Diabetics require a yearly eye exam to detect proliferative retinopathies.  If present, laser coagulation should be performed.

Nephropathy – If any form of protein is present in the urine give the DM pt ACEI’s.  These prevent nephropathies and ACEI’s are 1st line drugs in DM with HTN

Neuropathy – Yearly foot exams are important.  If neuropathy is present there is no need to delay treatment with gabapentin or pregabalin.

Erectile Dysfunction – Ask patient about this, sildenafil or tadalafil work well but do not give if they are also on nitrates

Gastroparesis – More common in long-term diabetics, there is impaired stretch-receptors and thus impaired motility.  Patient will have bloating, constipation, fullness, and diarrhea.  Give metoclopramide or erythromycin (increase gastric motility)

Diabetes Type 1 Type 2
Onset Juvenile/childhood Adult (increasingly common in youth today)
Body Type Thin Obese
DKA? Frequent Rare
Treatment Insulin 1st – lifestyle 2nd – oral hypoglyclemic agents

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