3 Electrolytes, Renal Function, and Fluid Balance Free Online FlashCards

How should laboratory results be interpreted safely?

Reference intervals vary by laboratory, method, age, and clinical context. Use the range on the report and consider the patient’s baseline, trends, symptoms, and overall condition.

What does the blood sodium concentration primarily reflect?

It reflects water relative to sodium, not total-body sodium.

What neurologic symptoms can hyponatremia cause?

Hyponatremia is sodium below $135\ \text{mEq/L}$. It may cause nausea, headache, confusion, lethargy, seizures, or coma, especially when it develops quickly.

What are key risks of hypokalemia?

Hypokalemia is potassium below $3.5\ \text{mEq/L}$. It may cause weakness, cramps, constipation, or ileus; severe deficiency can cause ECG changes and dangerous arrhythmias.

What is a critical safety rule for IV potassium?

Never give potassium by IV push. Potassium replacement, especially IV replacement, requires an order and a prescribed rate.

How can low magnesium affect potassium or calcium replacement?

Magnesium deficiency can make low potassium or low calcium difficult to correct.

Why should creatinine be compared with a patient’s baseline?

Creatinine may rise when filtration falls, but muscle mass and other factors affect its value. Interpret it in context of the patient’s baseline and trend.

What changes can meet a common acute kidney injury criterion?

AKI is suggested by a creatinine rise of at least $0.3\ \text{mg/dL}$ within $48$ hours, a rise to at least $1.5$ times baseline within $7$ days, or urine output below $0.5\ \text{mL/kg/hour}$ for at least $6$ hours.

What fluid change does a body-weight change of about $1\ \text{kg}$ represent?

A rapid weight change can help reveal fluid gain or loss; approximately $1\ \text{kg}$ of body-weight change corresponds to $1\ \text{L}$ of fluid, though other factors can affect weight.

What does hypernatremia usually indicate?

Hypernatremia is sodium above $145\ \text{mEq/L}$ and usually reflects water deficit or impaired access to water.

What serious effects can high magnesium cause?

High magnesium, particularly with kidney failure or magnesium-containing medicines, can cause diminished reflexes, hypotension, bradycardia, and respiratory depression.

What persistent findings can indicate chronic kidney disease?

Persistent eGFR below $60\ \text{mL/min/1.73 m}^2$ or persistent evidence of kidney damage can indicate chronic kidney disease. UACR above $30\ \text{mg/g}$ is abnormal; findings require clinical interpretation and persistence over time.