NCLEX Review Guide: Acute Complications of Diabetes Mellitus

Pathophysiology

• DKA occurs due to absolute insulin deficiency leading to hyperglycemia, ketone production, and metabolic acidosis. The body's inability to utilize glucose for energy forces it to break down fat, producing ketones that lower blood pH.
• This condition is most commonly seen in Type 1 diabetes but can occur in Type 2 diabetes during severe stress or illness when insulin requirements increase dramatically.

Clinical Manifestations

• The classic triad of DKA includes polydipsia, polyuria, and polyphagia, accompanied by profound dehydration. As acidosis progresses, patients develop Kussmaul respirations (deep, rapid breathing) to compensate for metabolic acidosis.
• Additional signs include fruity breath odor from acetone, abdominal pain, nausea/vomiting, altered mental status, and signs of dehydration (dry mucous membranes, poor skin turgor, tachycardia).

Nursing Management

1. Administer IV fluids (typically 0.9% NaCl) to correct dehydration and improve circulation
2. Initiate IV insulin therapy per protocol (usually regular insulin continuous infusion)
3. Monitor blood glucose hourly until stable
4. Assess electrolytes, particularly potassium, as levels may drop rapidly with insulin administration
5. Monitor acid-base status through arterial blood gases
6. Provide continuous cardiac monitoring for dysrhythmias related to electrolyte imbalances

Pathophysiology

• HHS is characterized by extreme hyperglycemia (>600 mg/dL), hyperosmolarity, and severe dehydration but without significant ketosis. There is enough insulin to prevent ketone formation but not enough to control blood glucose.
• This condition is most commonly seen in elderly patients with Type 2 diabetes and is often precipitated by acute illness, infection, or medications that affect carbohydrate metabolism.

Clinical Manifestations

• HHS develops more gradually than DKA, often over days to weeks, with progressive polyuria, polydipsia, and profound dehydration. The extreme dehydration (often 8-12 liters) leads to hyperosmolarity and thickened blood.
• Neurological symptoms are prominent and may include altered mental status ranging from confusion to coma, seizures, and focal neurological deficits that can mimic stroke. These symptoms are directly related to hyperosmolarity and dehydration of brain cells.

Nursing Management

1. Initiate aggressive IV fluid replacement (typically 0.9% NaCl, then 0.45% NaCl)
2. Administer IV insulin at lower doses than used for DKA
3. Monitor electrolytes closely, especially sodium and potassium
4. Assess for signs of cerebral edema during treatment
5. Implement thromboembolism prophylaxis due to hyperviscosity of blood
6. Monitor neurological status continuously

Pathophysiology

• Hypoglycemia occurs when blood glucose falls below 70 mg/dL, triggering the body's counterregulatory hormone response. The brain is particularly vulnerable to glucose deprivation as it cannot synthesize or store significant amounts of glucose.
• In diabetic patients, hypoglycemia typically results from insulin excess relative to carbohydrate intake, increased insulin sensitivity (after exercise), or impaired counterregulatory responses due to autonomic neuropathy.

Clinical Manifestations

• Hypoglycemia presents with two categories of symptoms: adrenergic (early) and neuroglycopenic (late). Adrenergic symptoms result from the sympathetic nervous system response and include trembling, palpitations, anxiety, diaphoresis, and hunger.
• Neuroglycopenic symptoms occur as the brain becomes glucose-deprived and include confusion, difficulty speaking, headache, seizures, and if untreated, loss of consciousness or coma. These symptoms typically appear when blood glucose falls below 50 mg/dL.

Nursing Management

1. For conscious patients: Administer 15-20g of fast-acting carbohydrate (4oz juice, glucose tablets)
2. Recheck blood glucose after 15 minutes
3. If still <70 mg/dL, repeat treatment
4. Once glucose >70 mg/dL, provide a complex carbohydrate and protein snack
5. For unconscious patients: Administer glucagon IM/SC or IV dextrose per protocol
6. Document episode and identify precipitating factors

Treatment Differences

• While both DKA and HHS require insulin therapy, fluid replacement is even more critical in HHS due to the profound dehydration. DKA treatment focuses on correcting both acidosis and hyperglycemia, while HHS treatment emphasizes gradual correction of hyperglycemia and hyperosmolarity.
• Bicarbonate administration may be considered in severe DKA (pH <7.0) but is not indicated in HHS. Additionally, potassium replacement is typically more aggressive in DKA due to the greater shifts associated with insulin therapy and acidosis correction.

Common Pitfalls in Recognition

Key Lab Values to Remember

Prioritizing Assessment Findings

1. Check ABCs (Airway, Breathing, Circulation) first in any acute complication
2. Assess mental status as an indicator of severity
3. Check vital signs for compensatory mechanisms (Kussmaul breathing in DKA)
4. Obtain blood glucose reading
5. Assess hydration status (skin turgor, mucous membranes, vital signs)
6. Check for precipitating factors (infection, medication changes, dietary changes)

NCLEX Question Strategies

• For questions about acute complications of diabetes, focus on distinguishing characteristics between DKA and HHS, especially regarding ketosis, acidosis, and glucose levels. Remember that mental status changes are more prominent in HHS while acidosis symptoms dominate in DKA.
• When answering treatment questions, remember the priority sequence: stabilize ABCs, then address the specific complication. For hypoglycemia, treatment is always the first priority before investigating the cause.