Pathophysiology Review: Infection Control, Cultures, and Fluid & Electrolyte Balance

Vocabulary flashcards covering core concepts from the lecture: infection control and culture logic, antibiotic strategy, altered mental status signs, and key fluid/electrolyte topics (sodium, potassium, calcium, magnesium) plus basic ECG relationships.

Culture

The process of collecting specimens (urine, sputum, blood, nasal/throat) to identify the source of infection and guide antibiotic therapy; lab growth takes about 2–3 days and sensitivity results guide drug choice.

Culture and Sensitivity (S/I/R)

Lab report showing how bacteria respond to antibiotics: Susceptible (S) means the antibiotic should kill the bacteria; Resistant (R) means it will not; Indeterminate (I) means effectiveness is uncertain.

Broad-spectrum antibiotic

An antibiotic that covers a wide range of bacteria and is used initially when the specific organism is unknown.

Narrow-spectrum antibiotic

An antibiotic targeted to a specific type of bacteria, used after culture results to minimize side effects.

Clari (Altered Mental Status) acronym

C: Confusion, L: Lethargy, A: Agitation, R: Restlessness, I: Irritability — signs of AMS related to electrolyte imbalance.

Hyponatremia

Low sodium level (Na+ < 135 mEq/L) with potential CNS symptoms such as dizziness, headaches, seizures, and confusion.

Hypernatremia

High sodium level (Na+ > 145 mEq/L) with potential CNS symptoms; disruption of CNS function due to sodium imbalance.

Sodium (Na+) role

Primary extracellular cation; affects brain and CNS function; normal range ≈135–145 mEq/L.

Potassium (K+) role

Primary intracellular cation; essential for muscle and especially cardiac function; normal range ≈3.5–5.0 mEq/L.

Hyperkalemia

Potassium > 5.0 mEq/L; can cause changes on ECG such as peaked T waves and risk of arrhythmias; requires prompt assessment and management.

Hypokalemia

Potassium < 3.5 mEq/L; can cause muscle weakness and potential cardiac rhythm issues.

Calcium (Ca2+) signs of hypocalcemia

Low calcium can cause muscle twitching and signs such as Chvostek’s sign (facial twitch) and Trousseau’s sign (carpopedal spasm).

Chvostek's sign

Facial muscle twitching when tapping the facial nerve, indicating hypocalcemia.

Trousseau's sign

Carpopedal spasm when a blood pressure cuff is inflated, indicating hypocalcemia.

Magnesium (Mg2+)

Normal range ≈1.5–2.5 mEq/L; important for cardiac and muscular function; magnesium deficiency can affect muscle function and interacts with calcium.

ECG waves basics

P wave: atrial depolarization; QRS complex: ventricular depolarization; T wave: ventricular repolarization; potassium levels can alter T wave morphology (e.g., peaked T waves in hyperkalemia).