# ⚡ Electrolytes & Acid-Base

![Urine Nephrology Skeleton Key graphic](https://urinenephrology.org/2025_UDPA_Lectures_Live/assets/Urine_Nephrology_Skeleton_key.jpeg)

## The BMP Skeleton Key Layout

How clinicians quickly sketch and interpret the basic metabolic panel

### Additional Key Electrolytes

Ca++ Mg++ PO4 ![Urine Nephrology Skeleton Key graphic](https://urinenephrology.org/2025_UDPA_Lectures_Live/assets/Urine_Nephrology_Skeleton_key.jpeg)

## Electrolyte Disorders

### 🔑 BMP + Ca + Mg + PO4 Overview & Approach

Systematic approach to complete electrolyte interpretation

#### Complete Electrolyte Panel

Na K Cl CO2 BUN/Cr + Ca++ + Mg++ + PO4

- **Master Skeleton Key:** BMP + Ca + Mg + PO4 approach
- **Systematic Review:** Don't miss critical interactions
- **Clinical Context:** History trending and patterns
- **Emergency Priorities:** Life-threatening findings first
- **Urinalysis Integration:** The ultimate diagnostic key

✅ Essential Foundation

### 🔬 Creatinine & Glomerular Hemodynamics

Determinants of GFR, creatinine handling, and eGFR limitations

#### GFR = K_(f) × (P_(GC) − P_(BS) − π_(GC))

Interactive hemodynamics visualization included

- **Starling Forces:** Arteriolar tone, PGC, and filtration pressure
- **3 Fates of Creatinine:** Filtered, secreted, reabsorbed
- **Drug Effects:** TMP, Tagamet, triamterene raise Cr without ΔeGFR
- **eGFR Limitations:** When to trust (and not trust) the number
- **AKI Disconnect:** Why Cr rise lags behind GFR changes

✅ Comprehensive Guide + Interactive

### 🌊 Hyponatremia

Na+ \< 135 mEq/L - Most common electrolyte disorder

- **Emergency Protocol:** RIB therapy (2024)
- **Diagnostic:** Urine osmolality key
- **Correction:** 4-8 mEq/L per 24h
- **Risk Factors:** Chronic, severe cases

Available

### 🔥 Hypernatremia

Na+ \> 145 mEq/L - Water deficit state

- **Water Deficit:** TBW × \[(Na/140) - 1\]
- **Correction:** ≤0.5 mEq/L/hr
- **Volume Status:** Hypo/Eu/Hypervolemic
- **Monitoring:** Neurologic status

Available

### ⬇️ Hypokalemia

K+ \< 3.5 mEq/L - Check magnesium first!

- **Critical Step:** Mg++ must be \>1.7 mg/dL
- **Replacement:** PO preferred over IV
- **ECG Changes:** U waves, flattened T
- **Complications:** Arrhythmias, weakness

Available

### ⚡ Hyperkalemia

K+ \> 5.0 mEq/L - Cardiac emergency

- **Stabilize:** Calcium gluconate 30mL IV
- **Shift:** Insulin + D50 + Albuterol
- **Remove:** K+ binders or dialysis
- **ECG:** Peaked T, wide QRS

Available

### 🦴 Calcium Disorders Reference

Comprehensive Ca++ Homeostasis Guide

- **Complete physiology:** PTH, Vitamin D, FGF23
- **Hypocalcemia guide:** Emergency protocols
- **Hypercalcemia guide:** VITAMINS TRAP mnemonic
- **Drug interactions:** Critical safety information

✅ Reference Available

### 📉 Hypocalcemia

Ca++ \< 8.5 mg/dL - Neuromuscular irritability

- **Emergency:** Ca-gluconate 1-2 amps IV
- **Critical:** Check Mg++ first!
- **Signs:** Chvostek, Trousseau

Available

### 📈 Hypercalcemia

Ca++ \> 10.5 mg/dL - "Stones, bones, groans"

- **2 Ps:** Primary hyperPTH vs PTHrP
- **Emergency:** IV fluids + bisphosphonates
- **VITAMINS TRAP:** PTH-independent causes

Available

### 📉 Hypomagnesemia

Mg++ \< 1.8 mg/dL - The forgotten electrolyte

- **Recognition:** PPI use, alcoholism, diuretics
- **Replacement:** Must correct FIRST
- **Priority:** K+ refractory until Mg++ corrected
- **Formulations:** Citrate/gluconate preferred

Available

### 📈 Hypermagnesemia

Mg++ \> 2.6 mg/dL - Rare but dangerous

- **Risk Factor:** CKD + Mg-containing meds
- **Emergency Antidote:** IV Calcium
- **Definitive:** Saline diuresis, dialysis
- **Monitor:** DTRs, respiratory depression

Available

### 🔍 Metabolic Acidosis & Acid-Base Analysis

Comprehensive acid-base disorders with systematic approach

- **ABC Method:** Systematic acid-base interpretation
- **Anion Gap Analysis:** MUDPILES vs USED CARP
- **Delta-Delta Ratio:** Mixed disorder detection
- **UAG Differentiation:** Renal vs GI causes
- **Interactive Calculator:** Complete analysis tool

✅ Comprehensive Guide

### 🔍 Metabolic Alkalosis

Chloride-responsive vs resistant: The urine chloride key

- **Urine Cl⁻ \< 20:** Volume/chloride depletion
- **Urine Cl⁻ \> 20:** Ongoing mineralocorticoid activity
- **Contraction Alkalosis:** Pathophysiology explained
- **Treatment Protocols:** Saline vs cause-specific
- **Interactive Calculator:** Complete assessment tool

✅ Complete Guide

### 🧪 Phosphorus Disorders Reference

Comprehensive PO₄ Management Guide

- **FGF23-Klotho axis:** Modern understanding
- **CKD-MBD:** Complete pathophysiology
- **Refeeding syndrome:** Prevention protocols
- **Binder comparison:** Evidence-based selection

✅ Reference Available

### 📉 Hypophosphatemia

PO₄ \< 2.5 mg/dL - Energy crisis

- **⚠️ Refeeding:** Life-threatening
- **Severe \<1.0:** Respiratory failure risk
- **Replace:** IV if \<2.0 mg/dL

Available

### 📈 Hyperphosphatemia

PO₄ \> 4.5 mg/dL - CKD complication

- **Ca×PO₄ \<55:** Prevent calcification
- **Binders:** Take WITH meals
- **Emergency:** Tumor lysis syndrome

Available

### 🍽️ Eating Disorders & the Kidney

Renal complications of anorexia, bulimia, and purging behaviors

- **Electrolyte Emergencies:** Hypokalemia, metabolic alkalosis, hypomagnesemia
- **Refeeding Syndrome:** Hypophosphatemia risk and prevention
- **Pseudo-Bartter:** Purging-induced electrolyte patterns
- **Renal Complications:** AKI, nephrolithiasis, CKD risk

✅ Comprehensive Guide

### 🌊 Comprehensive Hyponatremia Guide Available!

2024 evidence-based protocols including RIB therapy, correction science, and emerging treatments

📚 For Educational Purposes Only

© 2025 Andrew Bland MD - All Rights Reserved


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