Lecture 6 – Medication Toxicity and Electrolyte Imbalance Management

Drug Toxicity (5 drugs)

	Indication	Therapeutic level	Toxic level	others
Lithium (antimania)	Used for: Bipolar disorder, specifically to manage manic episodes. Note: Lithium is not used for treating depressive episodes in bipolar disorder, as it primarily controls mania.	0.6 – 1.2	> 2.0	Gray area 1.3 – 2.0
Lanoxin/ Digoxin	A-fib, CHF	1 – 2	> 2.0
Aminophylline (compound of bronchodilator theophylline)	Used for: Relaxing muscle spasms in the airways, helping to alleviate bronchospasm and improve breathing in respiratory conditions such as asthma or COPD. Purpose: Acts as a bronchodilator by relaxing smooth muscles around the airways, facilitating easier airflow.	10 – 20	> 20	Non-therapeutic Level: Less than 10 mcg/mL. Action: If the level is below 10, consider increasing the dose and assess patient compliance with the medication regimen to ensure proper therapeutic effect.
Dilantin (Phenytoin)	Used for: Managing and preventing seizures, particularly in conditions such as epilepsy.	10 – 20	> 20
Bilirubin	Definition: A byproduct of the breakdown of red blood cells (RBCs), processed by the liver and excreted in bile. Significance: Elevated bilirubin levels may indicate liver dysfunction or excessive RBC breakdown (e.g., jaundice, liver disease, hemolytic anemia).	Adults: Normal range is 0.2 – 1.2 mg/dL. Newborns: Levels are typically higher due to increased red blood cell breakdown in the first days of life.	Newborns: Elevated bilirubin levels between 10 – 20 mg/dL are concerning. Toxicity: Levels above 20 mg/dL can lead to dangerous conditions such as kernicterus (bilirubin-induced brain damage).	Newborn Hospitalization: Hospitalization is typically recommended if bilirubin levels are greater than 14 mg/dL to prevent complications such as jaundice or kernicterus.

• Memory Tip: 1-2 or 10-20
  • Low Toxic Levels (1-2):
    • Lithium and Lanoxin (Digoxin) – therapeutic range is in the 1s and 2s.
  • Higher Toxic Levels (10-20): Several other medications fall within the 10-20 range for toxicity.

3 Key Problems from Elevated Bilirubin Levels

1. Jaundice: Yellowing of the skin and eyes due to excess bilirubin in the blood.
   • Pathological Jaundice: Appears within the first 24 hours after birth and is concerning.
   • Physiological Jaundice: Occurs 2-3 days postpartum and is considered normal.
2. Kernicterus: Excess bilirubin (>20 mg/dL) in the brain, potentially leading to aseptic/sterile meningitis or encephalopathy.
3. Opisthotonos: Severe hyperextension of the newborn’s body due to meningeal irritation from kernicterus (this is a medical emergency).
   • NCLEX Question Tip: If a newborn is in opisthotonos, place them on their side to relieve pressure and irritation.

Hiatal Hernia vs. Dumping Syndrome (Opposite Conditions)

	Hiatal  Hernia	Dumping syndrome (“Drunk Shock Abdo distress”)
What is it?	Definition: A condition where part of the stomach pushes up through the diaphragm, causing regurgitation of gastric acid back into the esophagus. The issue is with the wrong direction of stomach contents moving upward into the esophagus, while the rate of digestion remains correct.	Definition: A condition where gastric contents are emptied too quickly into the duodenum. The contents move in the right direction but at the wrong rate (too fast), leading to a range of symptoms.
Signs and Symptoms	Symptoms are similar to GERD (gastroesophageal reflux disease), especially when lying down after a meal. Key Symptoms: – Heartburn – Indigestion Symptoms are often triggered by lying down after eating, as the stomach contents move upward into the esophagus.	Key Symptoms: Often described as “Drunk Shock + Abdominal Distress.” Drunk-like Symptoms: Due to blood being diverted to the gut. – Staggering gait – Impaired judgment – Emotional instability (labile) Shock-like Symptoms: Resulting from rapid fluid shifts. – Cold, clammy skin – Tachycardia (rapid heart rate) – Pale complexion Abdominal Distress: – Nausea and vomiting (N/V) – Diarrhea – Abdominal cramping and guarding – Borborygmi (loud bowel sounds) – Bloating and distention
Treatment – HOB – H20 – Carbs/ protein	Key Strategy: “Everything high” to promote faster stomach emptying and prevent reflux. 1. Elevate Head of Bed (HOB): Keep the head of the bed elevated for 1 hour after meals. 2. Increase Fluid Intake: Drink more fluids with meals to help move food through the stomach faster. 3. Increase Carbs, Decrease Protein: A high-carb, low-protein diet promotes quicker gastric emptying, reducing the chance of stomach contents moving back into the esophagus.	Key Strategy: “Everything low” to slow gastric emptying and prevent rapid shifts of stomach contents. 1. Lower Head of Bed (HOB): Keep the head of the bed low during meals and position the patient on their side to slow down gastric emptying. 2. Decrease Fluid Intake: Reduce fluid consumption during meals; instead, drink fluids 1 to 2 hours before or after meals to avoid speeding up stomach emptying. 3. Lower Carbs, Increase Protein: A low-carb, high-protein diet helps slow the digestive process and prevents rapid dumping of stomach contents into the small intestine.

• Key Concept: Protein and carbohydrates have opposite effects on digestion.
  • Protein: Bulks gastric content and takes longer to digest, moving more slowly through the gut.
• Hiatal Hernia:
  • Give low protein and high carbohydrates to speed up gastric emptying and prevent reflux.
• Dumping Syndrome:
  • Give high protein and low carbohydrates to slow gastric emptying and prevent rapid dumping of stomach contents into the small intestine.

Electrolytes – Key Points to Memorize:

1. Kalemias (K+): Potassium imbalances follow the same direction as the prefix, except for heart rate (HR) and urine output (UO), which move in the opposite direction.
2. Calcemias (Ca2+): Calcium imbalances move in the opposite direction of the prefix.
3. Magnesemias (Mg2+): Magnesium imbalances also move in the opposite direction of the prefix.
4. Sodium (Na+):
   • Hyponatremia: Associated with fluid overload (FVO).
   • Hypernatremia: Associated with dehydration (FVD).

1. Potassium (K+) – Kalemia

• Rule: Symptoms follow the same direction as the prefix, except for HR and UO, which move in the opposite direction.
• Hypokalemia (Low Potassium):
  • Symptoms: Decreased body functions.
    • Lethargy, bradypnea, paralytic ileus, constipation, muscle flaccidity, hyporeflexia (0-1+), tachycardia, polyuria.
• Hyperkalemia (High Potassium):
  • Symptoms: Increased body functions.
    • Seizures, agitation, irritability, tented T wave, ST elevation, tachypnea, diarrhea, borborygmi, spasticity, hyperreflexia (3+ or 4+), bradycardia, oliguria.

2. Calcium (Ca2+) – Calcemia

• Rule: Symptoms move in the opposite direction of the prefix.
• Hypocalcemia (Low Calcium):
  • Symptoms: Increased neuromuscular activity.
    • Agitation, irritability, 3+ or 4+ reflexes, spasms, seizures, tachycardia, Chvostek’s sign (facial twitch when tapping the cheek), Trousseau’s sign (carpal spasm with BP cuff inflation).
• Hypercalcemia (High Calcium):
  • Symptoms: Decreased neuromuscular activity.
    • Bradycardia, bradypnea, muscle flaccidity, hypoactive reflexes, lethargy, constipation.

3. Magnesium (Mg2+) – Magnesemia

• Rule: Symptoms move in the opposite direction of the prefix.
  • Note: If in doubt, choose calcium over magnesium when deciding between the two on an exam.
• Hypomagnesemia (Low Magnesium):
  • Symptoms: Increased neuromuscular activity.
    • Similar to hypocalcemia: Agitation, irritability, 3+ or 4+ reflexes, spasms, seizures, tachycardia, Chvostek’s sign, Trousseau’s sign.
• Hypermagnesemia (High Magnesium):
  • Symptoms: Decreased neuromuscular activity.
    • Similar to hypercalcemia: Bradycardia, bradypnea, muscle flaccidity, hypoactive reflexes, lethargy, constipation.

4. Sodium (Na+) – Hyponatremia vs. Hypernatremia

• Hyponatremia (Low Sodium) = Fluid Overload.
  • Treatment: Administer diuretics (Lasix) and restrict fluids.
• Hypernatremia (High Sodium) = Dehydration.
  • Treatment: Increase fluid intake.

General Signs of Electrolyte Imbalance

• Earliest Sign: Numbness and tingling (paresthesia), especially around the mouth (circumoral paresthesia).
• All Electrolyte Imbalances: Can cause muscle weakness (paresis).

Treatment of Potassium (K+) Imbalances

1. Hypokalemia (Low Potassium):
   • Treatment: Administer potassium supplements.
     • Caution:
       • Never push IV potassium.
       • Do not give more than 40 mEq/L of potassium in IV fluids.
2. Hyperkalemia (High Potassium):
   • This is more dangerous because it can cause heart arrest.
   • Fastest Solution: Administer D5W with regular insulin.
     • This temporarily shifts potassium from the blood into the cells.
     • Potassium in the blood is dangerous; potassium in the cells is not.
   • Permanent Solution: Administer Kayexalate (PO or enema).
     • It exchanges sodium for potassium in the gut, causing potassium to be excreted in the stool.
     • Note: This can result in hypernatremia (dehydration), so give fluids afterward.
   • Best Approach: Use both D5W with insulin for a quick fix and Kayexalate for a long-term solution.