Electrolyte Imbalances, Urinary Diagnostics, and Cardiovascular Labs

Comprehensive vocabulary flashcards covering electrolyte imbalances, dietary sources, urinary elimination lab values and diagnostic tests, and circulation/perfusion laboratory markers.

Normal Sodium ($\text{Na}^+$)

The standard adult serum reference range of $136 - 145\,\text{mEq/L}$ (commonly accepted as $135 - 145\,\text{mEq/L}$) as listed in Pagana.

Normal Potassium ($\text{K}^+$)

The standard adult serum reference range of $3.5 - 5.0\,\text{mEq/L}$ as listed in Pagana.

Normal Total Calcium ($\text{Ca}^{2+}$)

The standard adult serum reference range of $9.0 - 10.5\,\text{mg/dL}$. Note that ionized calcium levels are approximately half of total calcium.

Normal Magnesium ($\text{Mg}^{2+}$)

The standard adult serum reference range of $1.3 - 2.1\,\text{mEq/L}$ as listed in Pagana.

Normal Phosphate (Phosphorus)

The standard adult serum reference range of $3.0 - 4.5\,\text{mg/dL}$ as listed in Pagana.

POTSY

A mnemonic for dietary potassium sources: Potatoes with the skin, Oranges/orange juice, bananas, and beans, Tomatoes/tomato products, Salmon, clams, tuna, snapper, and Yogurt/other dairy.

Hypernatremia

Serum sodium level above normal, caused by excessive sodium intake (diet, IV fluids, meds) or water deficit (sweating, diabetic osmotic diuresis, fluid restrictions, GI loss). Signs include agitation, confusion, lethargy, decreased LOC, thirst, dry mucous membranes, poor skin turgor, tachycardia, hypotension, serum osmolality $> 300\,\text{mOsm/kg}$, and urine specific gravity $> 1.030$.

Hyponatremia

Serum sodium level below normal, caused by relative water excess (heart failure via ADH, renal failure, hypotonic IV fluids, polydipsia) or sodium loss (vomiting, diarrhea, diuretics). Signs include confusion, lethargy, decreased LOC, seizures, nausea/vomiting, and muscle weakness.

Hyperkalemia

Serum potassium level $> 5.0\,\text{mEq/L}$, commonly caused by renal failure, cellular 'crush' injuries, or potassium-sparing diuretics. Signs include irregular pulse, cardiac monitor changes, and GI cramping/diarrhea. Treated with loop diuretics, Kayexalate, IV regular insulin with dextrose, calcium, albuterol, or dialysis.

Hypokalemia

Serum potassium level $< 3.5\,\text{mEq/L}$, caused by loop diuretics or GI losses (vomiting or diarrhea). Manifests with irregular pulse, cardiac monitor changes, muscular weakness, and ileus. Treated with oral or IV potassium replacement, with IV potassium strictly NEVER administered via IV push.

Hypercalcemia

Serum total calcium level $> 10.5\,\text{mg/dL}$, caused by hyperparathyroidism, bone demineralization (prolonged immobility, cancer/tumors), or excess intake. Manifests with nausea, vomiting, constipation, muscle weakness, hypoactive reflexes, confusion, decreased LOC, and cardiac dysrhythmias.

Hypocalcemia

Serum total calcium level $< 9.0\,\text{mg/dL}$, caused by inadequate intake, malabsorption, lack of vitamin D, or elevated phosphorus. Characterized by numbness, tingling, muscle cramping, tetany, hyperactive reflexes, cardiac dysrhythmias, seizures, and positive Chvostek and Trousseau signs.

Hypermagnesemia

Serum magnesium level $> 2.1\,\text{mEq/L}$, caused by antacid/laxative overuse or renal disease. Manifests with drowsiness, lethargy, respiratory muscle weakness, decreased heart rate and blood pressure, reduced respiratory rate and depth, hypoactive reflexes, EKG changes, and risk of cardiac arrest.

Hypomagnesemia

Serum magnesium level $< 1.3\,\text{mEq/L}$, caused by alcohol abuse, liver disease, malnutrition, or GI losses. Presents similarly to hypocalcemia with muscle cramping, tetany, hyperactive reflexes, cardiac dysrhythmias, seizures, and positive Chvostek and Trousseau signs; treated with magnesium sulfate PO or IV (never IM).

Hyperphosphatemia

Serum phosphorus level $> 4.5\,\text{mg/dL}$, often caused by laxative overuse; presents with clinical manifestations similar to hypocalcemia and is treated by managing hypocalcemia and administering aluminum hydroxide as a phosphate binder.

Hypophosphatemia

Serum phosphorus level $< 3.0\,\text{mg/dL}$, displaying an inverse relationship with calcium and presenting with easy bruising and clinical manifestations similar to hypercalcemia; treated with PO or IV phosphate replacement.

Urine Specific Gravity

Urinalysis measurement of urine concentration with a normal range of $1.005 - 1.030$. Values $< 1.005$ indicate renal disease or overhydration; values $> 1.030$ indicate dehydration.

Proteinuria

The abnormal presence of protein in the urinalysis (normally negative), serving as a primary clinical indicator of renal disease and kidney dysfunction.

Blood Urea Nitrogen (BUN)

A blood test measuring kidney function with a normal range of $10 - 20\,\text{mg/dL}$. Values $> 20\,\text{mg/dL}$ indicate renal disease, liver disease, GI tract bleeding, or dehydration; values $< 10\,\text{mg/dL}$ indicate overhydration.

Serum Creatinine

A renal function blood test with a general reference range of $0.5 - 1.2\,\text{mg/dL}$. Values exceeding $1.2\,\text{mg/dL}$ point to renal dysfunction or dehydration.

Computed Axial Tomography (CT/CAT Scan) Abdomen/Pelvis

An indirect visualization diagnostic test used to view kidney stones, masses (renal tumors and cysts), and urine flow. Requires verifying contrast dye allergies and checking baseline renal function (creatinine/eGFR) due to the nephrotoxic potential of IV contrast dye.

Intravenous Pyelography (IVP)

An indirect visualization exam lasting approximately $30\,\text{minutes}$ where intravenous contrast dye is administered to evaluate the shape and size of the kidneys, ureters, and bladder, and confirm normal renal excretion.

Retrograde Pyelography

An invasive indirect visualization procedure in which a provider directly inserts a catheter into the ureters and injects contrast dye to visualize the urinary tract.

KUB ('Flat Plate')

A simple, noninvasive X-ray of the kidneys, ureters, and bladder performed in radiology or at the bedside requiring no special post-procedure care.

Cystoscopy

A direct visualization procedure wherein a provider inserts an endoscope through the urethra into the bladder to visualize urethral and bladder lining, collect tissue biopsies, or excise small tumors. Post-procedure care includes reporting bright red blood or clots, while pink-tinged urine is normal.

Hemoglobin (Hgb)

Laboratory measurement of the oxygen-carrying protein in the blood, with normal adult reference values of $13.5 - 17.5\,\text{g/dL}$ for males and $12.0 - 15.5\,\text{g/dL}$ for females.

Hematocrit (Hct)

Laboratory measurement of the percentage volume of erythrocytes in whole blood, with normal adult reference ranges of $40 - 54\%$ for males and $36 - 48\%$ for females.

Brain Natriuretic Peptide (BNP)

A cardiac diagnostic blood marker with normal levels $< 100\,\text{pg/mL}$. Levels of $100 - 400\,\text{pg/mL}$ indicate mild heart failure, $400 - 800\,\text{pg/mL}$ indicate moderate to severe heart failure, and $> 1800\,\text{pg/mL}$ indicate severe heart failure.

Troponin

A specific cardiac biomarker used to evaluate myocardial injury, with a normal reference level of $< 14\,\text{ng/L}$.

Lipid Panel Target Values

Cardiovascular risk markers with targets: Total Cholesterol $< 200$, Low-Density Lipoprotein (LDL) $< 100$, High-Density Lipoprotein (HDL) $> 60$, and Triglycerides $< 150$.

C-reactive Protein (CRP)

A blood biomarker measuring systemic inflammation, with a normal reference level of $< 10\,\text{mg/L}$.

Electrocardiogram (ECG)

A diagnostic assessment that provides a graphic rendering of the electrical activity of the heart.

Cardiac Catheterization

An invasive diagnostic procedure where a catheter is passed into the cardiac chambers to evaluate intracardiac pressures, blood flow dynamics, and the patency and size of chambers.

Remote Cardiac Monitoring

Continuous telemetry monitoring utilized to identify a patient's baseline rhythm and heart rate, recognize acute or significant rhythm variations, and detect lethal cardiac dysrhythmias.