Study Notes on Hyperglycemic Crises and Diabetic Complications

Overview of Hyperglycemic Crises

Hyperglycemic Hyperosmolar State (HHS)

  • HHS is characterized by:
    • Gradual onset of problems, especially in type 2 diabetics.
    • Sufficient insulin production to prevent ketone production and acidosis.
    • Symptoms typically triggered by illness or non-compliance with medication.
  • Key features include:
    • Extremely elevated blood glucose levels (600 to 800 mg/dL) versus DKA.
    • Significantly elevated serum osmolality (normal: 270-280 mOsm/kg, HHS: ≥320 mOsm/kg).
    • Severe dehydration, as indicated by dry mucous membranes and poor skin turgor.
    • Elevated Blood Urea Nitrogen (BUN) and creatinine levels.

Clinical Manifestations of HHS

  • Symptoms include:
    • Polydipsia (excessive thirst) and polyuria (excessive urination), leading to dehydration.
    • Mucous membranes become very dry.
    • Fatigue, neurological changes, and potential altered mental status.
    • Vital signs may show hypotension (low blood pressure) and tachycardia (increased heart rate).
  • Neurological concerns:
    • Monitor for signs of cerebral dehydration, as severe hyperosmolality can lead to neurological impairments, including paralysis.

Priority Nursing Interventions for HHS

  • Focus on airway, breathing, circulation (ABCs), emphasizing circulation due to dehydration.
  • Primary intervention: Replace fluids.
    • Start with normal saline or half-normal saline (isotonic or hypotonic solutions).
    • Avoid hypertonic solutions to prevent exacerbating dehydration.
  • Insulin administration is secondary; ensure adequate urine output before potassium replacement, as insulin shifts potassium into cells.
  • Importance of central venous pressure (CVP) monitoring:
    • Helps assess hemodynamic status and prevent fluid overload during treatment.
    • Normal CVP: 2-4 mmHg; HHS patients may present with CVP below 1 mmHg due to severe dehydration.

Diabetic Ketoacidosis (DKA)

Characteristics of DKA

  • Occurs primarily in type 1 diabetics due to autoimmune deficiency resulting in insufficient insulin production.
  • Signs and symptoms:
    • Polyuria, polydipsia due to elevated blood glucose.
    • Nausea and abdominal pain may develop.
    • Neurological changes, deep rapid Kussmaul respirations as compensation for metabolic acidosis.
    • Characteristic fruity (acetone) breath from ketosis.
    • Dehydration leading to tachycardia and hypotension.

Diagnostic Criteria for DKA

  • Blood glucose typically exceeds 300 mg/dL.
  • Laboratory tests confirm elevated hemoglobin, hematocrit, and presence of ketones in urine (glucosuria).
  • A metabolic panel may reveal elevated BUN and creatinine due to dehydration.
  • Arterial blood gas analysis will show metabolic acidosis (pH < 7.35, bicarbonate < 15 mEq/L).

Nursing Interventions for DKA

  • Priority: Address airway, breathing, circulation, emphasizing circulation due to potential for tachycardia and hypotension.
  • Fluid resuscitation begins with normal saline.
  • Administer regular insulin via IV (0.1 units/kg/hour), titrating steadily to avoid rapid drops in blood glucose (>50-75 mg/dL/hour).
  • Monitor blood glucose hourly; add dextrose to IV fluids when glucose falls below 250 mg/dL to prevent rapid hypoglycemia.
  • Telemetry monitoring needed due to potassium management.

Monitoring and Resolution of DKA

  • Indicators of effective treatment include:
    • Normalization of pH and bicarbonate levels.
    • Blood glucose returns to the normal range and absence of ketones in urine.

Complications of Diabetes

Microvascular Complications

  • Retinopathy:
    • Leading cause of blindness; involves damage to retinal microvasculature.
    • Symptoms include floaters, hazy vision, and potential loss of vision.
  • Nephropathy:
    • Kidney filtration impairment leading to protein leakage (microalbuminuria).
    • Risks associated with contrast media in imaging (e.g., CT scans) can result in acute renal failure.
  • Neuropathy:
    • Can be peripheral or autonomic, affecting sensation and leading to gait changes and injury risk.
    • Management includes medications like tricyclics, gabapentin, or duloxetine.

Macrovascular Complications

  • Increased risk for coronary artery disease (CAD) and cerebrovascular accidents (CVA).
  • Notable risk for silent myocardial infarctions.
  • Atherogenesis accelerated by chronic hyperglycemia leads to cardiovascular disease.

Management of Diabetic Care

  • For nephropathy, ACE inhibitors may provide renal protection, with precautions about side effects such as a persistent cough.
  • Ongoing monitoring of electrolyte levels, particularly potassium; anticipate and manage hypokalemia during insulin therapy.
  • Patient education is crucial, including adherence to treatment, recognition of signs of complications, and regular monitoring of blood sugars.
  • Stress the importance of hydration, especially for patients prone to HHS or DKA.