Electrolyte Abnormalities Summary
GENERAL APPROACH
- intake:
- redistribution:
output:
urinary
non-urinary
-> upper GI
-> mid GI
-> lower GI
-> other – skin, bleeding, sweat, RRT
POTASSIUM
- intake: oral intake, blood transfusion
- redistribution: acidosis, rhabdomyolysis, tumour lysis
- output:
urinary – RTA type 4, renal failure, adrenal insufficiency, DM, K+ sparring diuretics
- intake: inadequate intake
- redistribution: alkalosis, hypoMg2+, glucose infusion, periodic paralysis, beta-agonists
- output:
urinary – steroids (ex or en), DKA, hyperaldosteronism, Cushings, RTA, diuretics
non-urinary
-> upper GI – vomiting
-> mid GI – fistula
-> lower GI – diarrhoea
-> other – sweat, burns, bleeding, RRT
MAGNESIUM
- intake: usually iatrogenic (Mg infusion)
- redistribution:
- output:
urinary – renal failure increases risk of accumulation
- intake: TPN, malabsorption, alcoholism
- redistribution: insulin, hungry bone syndrome
- output:
urinary – RTA, diuretics, polyuria from any cause
non-urinary
-> upper GI – NG loss
-> lower GI – diarrhoea
CALCIUM
- intake: Ca2+, vitamin A or D, hypoMg2+, hypovolaemia, TPN
- redistribution: immobilization, malignancy, hyperparathyroidism, sarcoid, lithium, adrenal insufficiency, endocrine causes (thyrotoxicosis, acromegaly, phaeo)
- output:
urinary – thiazides
- intake: Ca2+, vitamin D, phenytoin (increased metabolism of vitamin D)
- redistribution: alkalosis, citrate toxicity, hyperphosphataemia, pancreatitis, tumour lysis syndrome, rhabdomyloysis, decreased bone turnover, hypoparathyroidism, drugs (bisphosphonates, PPI’s, SSRI’s, gentamicin)
- output:
urinary – ethylene glycol, cis-platin, protamine, loop diuretics
non-urinary – bleeding, plasmapheresis, citrate RRT
PHOSPHATE
- intake:
- redistribution:
- output: urinary
non-urinary
-> upper GI
-> mid GI
-> lower GI
-> other – skin, bleeding, sweat, RRT
- intake: malnutrition, phosphate binders, vitamin D, malabsorption, TPN
- redistribution: refeeding syndrome, insulin in DKA
- output:
urinary – diuretics, osmotic diuresis, hyperparathyroidism, proximal tubular dysfunction (Fanconi syndrome)
non-urinary
-> upper GI
-> mid GI
-> lower GI – diarrhoea
-> other – sweat, burns, sepsis, bleeding
SODIUM
- different to the rest!
- must think of mainly redistribution of H2O
To sort out:
(1) Osmolality
(2) Volume assessment
(3) Where is the H2O being lost from?
HYPOTONIC
Hypovolaemic
- urinary (urinary Na+ high) – diuretics, osmotic diuretics, RTA, salt wasting, mineralocorticoid deficiencies
- non-urinary (urinary Na low)
-> upper GI – vomiting
-> mid GI – pancreatitis, bowel obstruction
-> lower GI – diarrhoea, bowel preparation
-> other – skin, bleeding, sweat
Euvolaemic
-> SIADH (most common)
-> psychogenic polydipsia
-> hypotonic IVF therapy
-> adrenal insufficiency
-> hypothyroidism
Hypervolaemic
-> CHF
-> cirrhosis
-> nephrotic syndrome
-> hypothyroidism
-> pregnancy
-> TURP syndrome
ISOTONIC (pseudohyponatraemia)
- high proteins
- high lipids
HYPERTONIC
- glucose
- mannitol
- sorbitol
- radiocontrast
- advanced renal disease (need to correct osmolality = measured osmolalilty – urea)
References and Links
Introduction to ICU Series
Introduction to ICU Series Landing Page
DAY TO DAY ICU: FASTHUG, ICU Ward Round, Clinical Examination, Communication in a Crisis, Documenting the ward round in ICU, Human Factors
AIRWAY: Bag Valve Mask Ventilation, Oropharyngeal Airway, Nasopharyngeal Airway, Endotracheal Tube (ETT), Tracheostomy Tubes
BREATHING: Positive End Expiratory Pressure (PEEP), High Flow Nasal Prongs (HFNP), Intubation and Mechanical Ventilation, Mechanical Ventilation Overview, Non-invasive Ventilation (NIV)
CIRCULATION: Arrhythmias, Atrial Fibrillation, ICU after Cardiac Surgery, Pacing Modes, ECMO, Shock
CNS: Brain Death, Delirium in the ICU, Examination of the Unconscious Patient, External-ventricular Drain (EVD), Sedation in the ICU
GASTROINTESTINAL: Enteral Nutrition vs Parenteral Nutrition, Intolerance to EN, Prokinetics, Stress Ulcer Prophylaxis (SUP), Ileus
GENITOURINARY: Acute Kidney Injury (AKI), CRRT Indications
HAEMATOLOGICAL: Anaemia, Blood Products, Massive Transfusion Protocol (MTP)
INFECTIOUS DISEASE: Antimicrobial Stewardship, Antimicrobial Quick Reference, Central Line Associated Bacterial Infection (CLABSI), Handwashing in ICU, Neutropenic Sepsis, Nosocomial Infections, Sepsis Overview
SPECIAL GROUPS IN ICU: Early Management of the Critically Ill Child, Paediatric Formulas, Paediatric Vital Signs, Pregnancy and ICU, Obesity, Elderly
FLUIDS AND ELECTROLYTES: Albumin vs 0.9% Saline, Assessing Fluid Status, Electrolyte Abnormalities, Hypertonic Saline
PHARMACOLOGY: Drug Infusion Doses, Summary of Vasopressors, Prokinetics, Steroid Conversion, GI Drug Absorption in Critical Illness
PROCEDURES: Arterial line, CVC, Intercostal Catheter (ICC), Intraosseous Needle, Underwater seal drain, Naso- and Orogastric Tubes (NGT/OGT), Rapid Infusion Catheter (RIC)
INVESTIGATIONS: ABG Interpretation, Echo in ICU, CXR in ICU, Routine daily CXR, FBC, TEG/ROTEM, US in Critical Care
ICU MONITORING: NIBP vs Arterial line, Arterial Line Pressure Transduction, Cardiac Output, Central Venous Pressure (CVP), CO2 / Capnography, Pulmonary Artery Catheter (PAC / Swan-Ganz), Pulse Oximeter
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC
