🏠 Study Hub 🖼️ Infographics
Nursing Field Notes / Renal + Fluid · Pathophysiology Course

Electrolyte Imbalances ⚖️

NG-034 RENAL + FLUID ADHD-friendly visual edition

An imbalance is just an electrolyte's job going wrong. Potassium pumps, sodium swells, magnesium mellows, calcium contracts — so every sign you assess is that job turned up or turned down.

📄 Simple Nursing original — opens in Drive →

🔀 K & Na follow the numberHigh K = high signs. Low K = low & slow.
🔁 Mg & Ca run BACKWARDSLow Mg / low Ca = excited. High = sedated.
🚨 Peak · Twist · Shallow · SeizeThe four findings that kill.
🪞 Phosphate = calcium flippedRead the calcium picture backwards.
🧭

PATTERN

STEP 1 · THE MASTER RULE

Twelve imbalances, one question: is the body EXCITED or SEDATED?

⚡😴 The excitability checkerboard — low value vs HIGH value

Ask the value. Then ask the body. ⬇️ LOW value (hypo-) ⬆️ HIGH value (hyper-) 🫀 Potassium K+ · PRIORITY FOLLOWS ✔ 😴 SEDATED — low & slow shallow respirations · ↓ DTR · flat T + U constipation · paralytic ileus ⚡ EXCITED — HIGH pumps peaked T waves · ↑ DTR · paresthesia diarrhea · hyperactive bowel sounds 💧 Sodium Na+ · Cl− copies FOLLOWS ✔ 😴 Brain low & slow headache = cerebral edema · seizures fatigue & cramps · respiratory arrest ⚡ Body big & bloated edema · flushed skin · ↑ muscle tone swollen dry tongue · nausea & vomiting 😌 Magnesium Mg+ · mellows BACKWARDS ⇄ ⚡ EXCITED — mellow lost Torsades de Pointes · V Fib HYPERreflexia · diarrhea 😴 SEDATED — too mellow heart block · depressed respirations hyporeflexia · hypoactive bowel sounds 🦴 Calcium Ca · Phos mirrors BACKWARDS ⇄ ⚡ EXCITED — calm lost Trousseau's · Chvostek's · tetany weak bones, blood, beats · diarrhea 😴 SEDATED — too calm stones, moans & groans · constipation bone pain · weakness & lethargy See the checkerboard? K & Na go the way the number goes — Mg & Ca do the opposite.

↔ swipe the chart sideways to read it all

🧠 “K and Na are honest — Mag and Calcium are liars.” High potassium really does make everything high; high magnesium makes everything low.

🗣️ The naming rule + the jobs TEST TIP

HYPER = “HIGH” (over the range) · Hypo = “low” (below the range).

  • P — Potassium K+ Pumps the heart · Priority ⭐
  • S — Sodium Na+ Swells the body with FLUID (BP · blood volume · pH)
  • M — Magnesium Mg+ Mellows the muscles
  • C — Calcium Ca Contracts the muscles — keeps the 3 Bs strong: 🦴 Bone · 🩸 Blood (clotting) · 🫀 Beats (heart)

🧂 Chloride Cl− is related to sodium — same three jobs. ⚖️ Phosphate has an inverse relationship with Calcium: Ca HIGH = Phosphate Low · Ca Low = Phosphate HIGH.

🧠 The job predicts the symptom. Ask “what does this one do?” before you memorize a single sign.

💦 Engine 1 — the LOWs: fluid out, electrolytes out

Fluid loss = electrolyte loss. “Where fluids flow, Electrolytes Goooo!”

  • 🍑 The 4 Ds + A (low K+): Diarrhea · Diuretics · Diet · DKA · Aldosterone
  • 😅 Low Na+: sweating · excess water intake (running in the extreme heat) TEST TIP · SIADH (excess ADH) · vomiting & diarrhea · diuretics & diuresis · diet low in salt · low aldosterone
  • 🤮 Low Cl−: vomiting → alkalosis
  • 🌾 Low Mg+: Crohn's disease · celiac disease
🧠 Memory Trick for AL(dosterone): A – Adds Sodium · L – Loses Potassium. So LOW aldosterone does the reverse — potassium piles up.

🧱 Engine 2 — the HIGHs: can't clear them, or making too many

  • 🫘 Renal failure TEST TIP (chronic kidney disease) → HYPERkalemia · HYPERmagnesemia · HYPERphosphatemia — and HYPOcalcemia (phosphate's mirror)
  • 🧪 Low aldosterone → HYPERkalemia
  • 🦴 Hyperparathyroidism — High PTH = High Calcium → HYPERcalcemia + HYPOphosphatemia. Also cancer, immobility, genetics
  • 🏜️ Low ADH — DI: Diabetes Insipidus (Think Dry Inside), rapid respirations, watery diarrhea, loss of thirst → HYPERnatremia
  • 🍷 Alcoholism · malnourishment → magnesium trouble
🧠 “Kidneys quit, the highs sit.” K+, Mg+ and Phosphate pile up — and calcium falls, because calcium is phosphate's mirror.
👀

PICTURE

STEP 2 · READ THE BODY

Four systems tell the whole story — heart, nerves & muscles, gut, lungs & brain. Find the system, then ask: excited or sedated?

🫀 The heart — the strip names the electrolyte

⬆️ HYPERkalemia — peaked T + ST elevation ⛰️ tall, pointed T — the mountain ⬇️ HYPOkalemia — flat T, ST depression, U wave flat T U wave 🌊 ⬇️ HYPOmagnesemia — Torsades de Pointes TOP TESTED

↔ swipe the chart sideways to read it all

🫀 What the heart showsWhich imbalance
Peaked T waves & ST elevation
severe: V Fib & Cardiac Arrest · hypotension & bradycardia		⬆️ HYPERkalemia (over 5.0)
Flat T waves, ST depression & U wave
low & slow pump		⬇️ HYPOkalemia
Torsades de Pointes & V Fib TOP TESTED⬇️ HYPOmagnesemia (below 1.3)
Heart block · hypotension · bradycardia⬆️ HYPERmagnesemia (over 2.1)
Weak Beats — cardiac dysrhythmias⬇️ HYPOcalcemia (below 9.0)
🧠 Peak = potassium HIGH. Twist = magnesium LOW. One rides a mountain, one rides a corkscrew.

💪 Nerves & muscles — the reflex tells you the direction

🔨 Deep tendon reflexes (DTR) 0 1+ 2+ 3+ 4+ ◀ hyporeflexia normal HYPERreflexia ▶ 😴 DECREASED DTR ⬇️ HYPOkalemia ⬆️ HYPERmagnesemia flaccid paralysis, cramps ⚡ INCREASED DTR ⬆️ HYPERkalemia ⬇️ HYPOmagnesemia ⬇️ HYPOcalcemia · tetany One hammer, opposite answers.
  • ⬆️ HYPERkalemia: increased DTR · paralysis & paresthesia (tingling) · muscle weakness (general feeling of heaviness)
  • ⬇️ HYPOkalemia: decreased DTR · muscle cramping & flaccid paralysis (paralyzed limbs)
  • ⬇️ HYPOcalcemia: T – Trousseau's Sign (“twerking arm” when BP cuff on) + Tetany · C – Chvostek's Sign (cheek smile when stroking face)
  • ⬆️ HYPERcalcemia: severe muscle weakness & lethargy · bone pain
  • 💧 Sodium: low = fatigue & muscle cramps · HIGH = increased muscle tone
🧠 Trousseau = Twerking arm · Chvostek = Cheek smile. Both mean calcium is LOW.

🚽 The gut — fast or frozen

💨 Fast: diarrhea + hyperactive bowel sounds🧊 Frozen: constipation + hypoactive bowel sounds
⬆️ HYPERkalemia (HIGH pumps)
⬇️ HYPOmagnesemia
⬇️ HYPOcalcemia		 ⬇️ HYPOkalemia — paralytic ileus (paralyzed intestine) PRIORITY risk for SBO
⬆️ HYPERmagnesemia
⬆️ HYPERcalcemia

🎈 HIGH sodium — body big & bloated: edema · flushed “red & rosey” skin · increased muscle tone · swollen dry tongue 👅 · nausea & vomiting. HIGH chloride copies it.

🧠 Excited gut runs 💩 · sedated gut stops 🧊. A frozen gut in a low-K+ client is the one that becomes a bowel obstruction.

🫁🧠 Lungs & brain — where it turns deadly

  • 🚨 Shallow Respirations! MOST DEADLY → ⬇️ HYPOkalemia (the breathing muscles are muscles too)
  • 😴 Depressed respirations → ⬆️ HYPERmagnesemia (too mellow)
  • 🚨 Respiratory arrest → ⬇️ HYPOnatremia
  • 🧠 Headache = cerebral edema · mental status changes · seizures & coma → ⬇️ HYPOnatremia
  • 🌡️ Fever → ⬇️ HYPOchloremia (the only difference from low sodium)
🧠 Low salt drowns the brain 🌊 · low potassium drops the breath 🫁. Two different “low & slow,” two different killers.

👯 The look-alikes — twins that share a picture

The twinsSame pictureThe tell 🔍
⬇️ HYPOkalemia
⬆️ HYPERmagnesemia		 Low & slow everywhere — depressed & shallow respirations, hypoactive bowel sounds, decreased DTR The strip: flat T + U wave = low K+ · heart block = high Mg+
⬆️ HYPERkalemia
⬇️ HYPOmagnesemia		 Excited everywhere — increased DTR, diarrhea, hyperactive bowel sounds The strip: peaked T = high K+ · Torsades = low Mg+
⬇️ HYPOcalcemia
⬆️ HYPERphosphatemia		 Trousseau's & Tetany · Chvostek's · weak B's (bones, blood, beats) None — “Think Low Calcium signs.” Phosphate is the mirror 🪞
⬆️ HYPERcalcemia
⬇️ HYPOphosphatemia		 Kidney stones, moans & groans (Renal Calculi) · constipation · bone pain · severe muscle weakness & lethargy None — “Think High Calcium signs.” Same mirror, other end 🪞
⬇️ HYPOnatremia
⬇️ HYPOchloremia		 NEARLY SAME AS low SODIUM — fatigue & muscle cramps 🌡️ Fever (only difference) = chloride
⬆️ HYPERnatremia
⬆️ HYPERchloremia		 NEARLY SAME AS HIGH SODIUM — swollen dry tongue · nausea & vomiting Chloride just copies sodium — learn salt once
🧠 Two twins per shelf, one tell each. When two imbalances look identical, the answer is the ECG strip or the fever — nothing else separates them.
🚨

PRIORITY

STEP 3 · WHAT KILLS FIRST

Sort every finding by how fast it kills — that is exactly how the exam sorts them too.

📏 The whole board — where the number sits, what waits at each end

⬇️ LOW — “hypo” NORMAL ⬆️ HIGH — “HYPER” 🫀 Potassium K+ · PRIORITY below 3.5 🫁 shallow respirations 3.5 – 5.0 over 5.0 ⛰️ peaked T → V Fib & cardiac arrest 💧 Sodium Na+ below 135 🧠 seizures & coma 135 – 145 over 145 🎈 edema · flushed skin · dry tongue 🧂 Chloride Cl− · salt's shadow below 97 🌡️ low-Na picture + FEVER 97 – 107 over 107 👅 high-Na picture · dry tongue · N/V 😌 Magnesium Mg+ · BACKWARDS below 1.3 🌀 Torsades de Pointes 1.3 – 2.1 over 2.1 🧱 heart block · depressed respirations 🦴 Calcium Ca · BACKWARDS below 9.0 💪 Trousseau's · Chvostek's 9.0 – 10.5 over 10.5 🪨 stones, moans & groans · constipation 🪞 Phosphate calcium, flipped below 3.0 = HIGH-calcium picture 3.0 – 4.5 over 4.5 = LOW-calcium picture (tetany) Below the green band = “hypo” (low). Above it = “HYPER” (HIGH). Phosphate reads as calcium, flipped.

↔ swipe the chart sideways to read it all

Note: the source card prints HYPOkalemia as “below 3.0”; the normal range it gives is 3.5 – 5.0, so anything under 3.5 is already low.

🚨 The killers — in order of how fast they end the shift

1
🫁 Shallow Respirations — ⬇️ HYPOkalemia MOST DEADLY
potassium runs muscles, and breathing is muscle work
2
🌀 Torsades de Pointes & V Fib — ⬇️ HYPOmagnesemia TOP TESTED
3
⛰️ Peaked T waves → V Fib & Cardiac Arrest — ⬆️ HYPERkalemia
K+ = Priority because K+ Pumps the heart
4
🧠 Seizures & Coma · Respiratory Arrest — ⬇️ HYPOnatremia (cerebral edema)
5
🧱 Heart block · hypotension · bradycardia — ⬆️ HYPERmagnesemia
6
🚽 Paralytic ileus (paralyzed intestine) — ⬇️ HYPOkalemia · PRIORITY risk for SBO
🧠 “Peak · Twist · Shallow · Seize.” Peaked T (high K+) · Twisting torsades (low Mg+) · Shallow breaths (low K+) · Seizures (low Na+). Four words, four codes.

⭐ Why potassium always goes first

P = Potassium · Pumps the heart · PRIORITY.

Its window is tiny — 3.5 – 5.0 — and both ends land on the rhythm strip. That is why it leads every electrolyte list you will ever see.

⚖️ Second in line: magnesium, because low Mg+ is the one that produces Torsades de Pointes.

🧠 Heart first, breath second, brain third. If two electrolytes are abnormal, answer the one on the monitor.

🎯 The most-tested short list TEST TIP

“The MOST deadly conditions are typically the MOST tested conditions, since the main goal of nursing school is to create safe nurses.”

  • 🌀 Torsades de Pointes = LOW magnesium TOP TESTED
  • 🫘 Renal failure / CKD TEST TIP → HYPOcalcemia and HYPERphosphatemia
  • 💦 Excess water intake (running in the extreme heat) TEST TIP → HYPOnatremia
  • 🗣️ HYPER = “HIGH” · Hypo = “low” — read the word before you read the number
🧠 “Kidneys quit, the highs sit.” K+ ⬆ · Mg+ ⬆ · Phosphate ⬆ — and calcium ⬇, every time.
⚡

QUICK RECALL

SAY IT OUT LOUD
🔀 K & Na are honestThe value and the body go the same way.
🔁 Mg & Ca are liarsLow = excited · HIGH = sedated.
🚨 Peak · Twist · Shallow · SeizeHigh K · low Mg · low K · low Na.
🧱 Kidneys quit, the highs sitK⬆ Mg⬆ Phos⬆ — and calcium ⬇.
🎯 Cover & check — 4 rapid-fire questions
Q1: The monitor shows a flat T wave with a U wave, and the client's breathing is shallow. Name the imbalance — and why it's the priority.
HYPOkalemia. Shallow respirations are its MOST DEADLY sign — low potassium takes the breathing muscles with it.
Q2: Two clients. One is hyperreflexic with diarrhea; the other is hyporeflexic with depressed respirations. Same electrolyte — which, and which direction each?
Magnesium. Low Mg+ = mellow lost → excited (hyperreflexia, diarrhea, Torsades). High Mg+ = too mellow → hyporeflexia, depressed respirations, heart block.
Q3: A client in renal failure — which three electrolytes climb, and which one falls?
Up: potassium, magnesium, phosphate. Down: calcium — because calcium has an inverse relationship with phosphate. “Kidneys quit, the highs sit.”
Q4: Which two electrolytes run BACKWARDS — where a HIGH value makes a slow, sedated body?
Magnesium and calcium. High Mg+ = heart block and depressed respirations; high Ca = stones, constipation, weakness & lethargy.