Articles
Vaccination Referrals from ED Paediatric Antimicrobial Guidance Children’s Services Resolution and Escalation Protocol Blunt Chest Wall Trauma/Rib Fractures Information for Parents Carers of Children Having Investigations in Relation to Unexplained Injuries + Consent form Bruising and Injuries in Babies and Children – Parents Leaflet Multi-Agency Protocol for Injuries to Non-Mobile Children Flowchart for children attending Galloway Community Hospital (GCH) for NAI Follow Up Skeletal Survey Flowchart for children attending DGRI for NAI Follow-Up Skeletal Survey Cognitive Function Conscious Level Kidney Biopsy Complications Parenteral Iron for Non-HD CKD Patients Fracture Management Guidelines (Paediatric) Fracture Management Guidelines (Adult) Management of Hypertension in Acute Stroke Prescribing for CAU Patients Still in ED Hypothermia Deactivation of Implantable Cardioverter Defibrillator Myeloma Croup Care Of Burns In Scotland (COBIS) Paediatric Guidance Management of Epistaxis Sore Throat Differential Diagnosis Dizziness Differential Diagnosis Peritonsillar Abscess/Quinsy Acute Tonsillitis Acute Mastoiditis Otitis Media Otitis Externa Extravasation of IV Amiodarone WoS Paediatric Drooling and Aspiration Guideline Palliative Care – How to Refer Eating Disorders Stroke Care Warfarin Anticoagulation for AF, DVT and PE Molnupiravir MyPsych Foundation Doctors Toolkit Paediatric Febrile Neutropenia Guidance PAEDIATRIC HYPOGLYCAEMIA MANAGEMENT in NON DIABETIC CHILDREN   Paediatric Diabetic Ketoacidosis (DKA) Guideline Child Protection Policies and Procedures (D&G) Management of Acute Behavioural Challenges in Adolescents and Young People presenting to Secondary Care Cancer of Unknown Primary Patients Returning from Interventional Cardiac Procedure Treatment of Malaria Discharging Patients on High Dose Steroids Sotrovimab Paediatric Ketone Correction Guideline Insulin Correction Factor Table (Paediatrics) Management of uncomplicated Henoch-Schonlein Purpura (HSP) in under 16s Management of Hypoglycaemia in Children with Type 1 Diabetes Newly diagnosed diabetic – not in DKA (Walking wounded) Proton Pump Inhibitor Guideline for Neonatal and Paediatrics Stroke – Post Thrombolysis Neonatal Guidelines Gentamicin Prescribing (Paediatrics) Management of Anaphylaxis (Paediatrics) Management of Prolonged Seizures (Convulsive Status Epilepticus) in Children Bronchiolitis Acute Wheeze or Asthma in Paediatrics Conscious Proning Covid-19 Basics Remdesivir Thromboprophylaxis Identifying Patients in the Highest Risk Groups Steroids for Patients with Covid-19 Infection IL-6 Inhibitors – Tocilizumab or Sarilumab Baricitinib Paxlovid (Nirmatrelvir/Ritonavir) Influenza A Inhalers for Adults with Asthma Standard Operating Procedure for AMU Trigger Finger/Thumb Osteoarthritis of the Hand/Thumb Mallet Finger Ganglion Dupuytren’s Contracture De Quervain’s Tenosynovitis Carpal Tunnel Syndrome Prescribing Advice on Admission – Clozapine Prescribing Advice on Admission – Methadone/Buprenorphine Prescribing Advice on Admission – Corticosteroids Prescribing Advice on Admission – Items Not Prescribed by GP Prescribing Advice on Admission – Patients on Chemotherapy Regimes Prescribing Advice on Admission – Medication for Parkinson’s Disease Prescribing Advice on Admission – Insulin Prescribing Advice on Admission Medical Emergencies in Eating Disorders (MEED) Gentamicin & Vancomycin HIV Testing Guidelines Metabolic Syndrome Associated Fatty Liver Disease (MAFLD) Greener Inhaler Prescribing C4 Predischarge Beds Handover Safe and Secure Handling of Medicines Blood Glucose & Steroids IV Fentanyl & Morphine for Acute Pain in Adults Assessment & Management of Acute Pain Hospitalised and Has Coronavirus19 Infection (No suspected Viral Pneumonia Syndrome) Hospitalised Due to Coronavirus19 with Likely Viral Pneumonia Bi-Level NIV S/T Guidelines for CCU Phase Bi-Level NIV S/T Guidelines for ED Phase Adults With Incapacity Premenstrual Syndrome Pelvic USS Boarding Coeliac diagnosis pathway (Adults) Voice clinic Ear Wax Dermatology Squamous Cell Carcinoma (SCC) Malignant Melanoma Basal Cell Carcinoma (BCC) Nipple Discharge Early Cancer Diagnostic Clinic (ECDC) Genetics Referrals Breast Infections Breast Pain Primary Care Prescribing Guidelines Emergency Department Anaesthetics and Chronic Pain Team Respiratory Referrals Chronic Cough Pathway GP Clinical Handbook Test Paediatric Bronchiolitis Early Cancer Diagnosis Clinic (ECDC) Obstetrics & Gynaecology/Medicine Admission Agreement Idiopathic Intrancranial Hypertension Urology Out of Hours Urology Out of Hours Sengstaken/Minnesota Tube for Bleeding Varices Eradication of Helicobacter pylori Transfer from Galloway Community Hospital Repatriation of Patients from Tertiary Hospitals THROMBOPROPHYLAXIS IN PREGNANCY – Appendix 1, Risk factors THROMBOPROPHYLAXIS IN PREGNANCY – Appendix 3, Postnatal assessment & management THROMBOPROPHYLAXIS IN PREGNANCY – Appendix 4 THROMBOPROPHYLAXIS IN PREGNANCY – Appendix 2, Management of women with previous VTE THROMBOPROPHYLAXIS IN PREGNANCY, LABOUR AND THE PUERPERIUM Orthopaedic VTE Risk Assessment Sodium Glucose Transporter 2 Inhibitors (SGLT2i) Cardiology Referrals Vascular Referrals ‘Watershed’ Conditions Myasthenia Gravis Gentamicin in Renal Replacement Therapy Vancomycin in Renal Replacement Therapy REDMAP Poster Realistic Conversations Summary Plan for Deteriorating Health Treatment Escalation Plans Ambulatory Care for Blood and/or Iron Infusion Principles for Light Touch Patients – B2 Clostridiodes difficile Infection Post Astra Zeneca Vaccine Headache Blood Culture Rhabdomyolysis Analgesia Acute Appendicitis Small Bowel Obstruction Elective Admission – Colorectal Surgery Trauma Admissions Post-operative Care Gallstone Disease Vasopressors and Inotropes/Chronotropes Shock Elective Admission – ERCP Elective Admission – Orthopaedics Laxatives Fat Embolism Compartment Syndrome Surgical Post-operative Complications Stoma Diverticular Disease High Dose Steroid Pre-Treatment Checklist Acute Surgical Admissions Level 1 CCU Medical Area Acute Oncology STEMI Thrombolysis Protocol Haemolytic Anaemia Conversion Charts Anticipatory ‘As Required’ Medications Syringe Driver Chart Scottish Palliative Care Guidelines Covid-19 Sick Day Rules for Patients with Primary Adrenal Insufficiency Diabetic Retinopathy Coming Off Benzodiazepines and “Z” Drugs Dental Abscess Facial Trauma – Mandibular Fractures Facial Trauma – Orbital Fractures Facial Trauma – Zygoma Platelet Transfusion Death Certification Parenteral Iron in Adults >18 Years OPAT SBAR (Complex Infections) Mental Health Liaison Team Referrals STEMI Admitting Patients with Tracheostomy/Laryngectomy to DGRI Emergency Laryngectomy Management Emergency Tracheostomy Management Safe Transfer of Patients with Tracheostomy/Laryngectomy within DGRI Other Tracheostomy Documents Systemic Anticancer Therapy Toxicity Haemodialysis Medication Prescribing Breaking Bad News by Telephone End of Life Diabetes Care Adrenal Insufficiency Serotonin Syndrome DGRI Referrals Confirmation of Death Neuroleptic Malignant Syndrome Pulmonary Embolism Deep Vein Thrombosis of Lower Extremities Exacerbation of COPD Contrast Associated AKI Acute Kidney Injury – Introduction Paracetamol Hypertensive Emergencies Staphylococcus aureus Bacteraemia (SAB) Rate Control in AF Common Scenarios Acute Severe Ulcerative Colitis IV Fluid Prescription in Adults Chronic Obstructive Pulmonary Disease Legionnaires Disease Septic Arthritis Guillain-Barré Syndrome Back Pain Anaesthetics – Unscheduled Procedures Requests Hyperglycaemia & Steroids Variable Rate Insulin Infusion Decompensated Liver Disease Fast Atrial Fibrillation – ACP Hyperkalaemia Contraindications to MRI Magnetic Resonance Imaging Bleeding with Other Antithrombotics In-patient Hyperglycaemia Management Anaemia (Management) – ACP Suspected NSTEMI – ACP Guidance on Chaperones Compulsory Admission and Treatment Radiology Immediate Discharge Letter Alcohol Withdrawal Fentanyl Patches in the Last Days of Life Care in the Last Days of Life Low Molecular Weight Heparin Interstitial Lung Disease Haematinic Testing Thromboprophylaxis for Non-Covid Patients Lung Cancer Osteoporosis Heart Failure Fluid Replacement in AKI Death & The Procurator Fiscal Thrombophilia Screening Neutropenic Sepsis Acute Vertigo Aortic Dissection Antithrombotics in Hip Fracture Transient Global Amnesia Hypomagnesaemia Hypophosphataemia Oxygen Therapy Falls – ACP Falls Acute Asthma Oncology Contact Details & General Advice Reversal of Warfarin Lumbar Puncture, Antiplatelet & Anticoagulant Drugs Antithrombotics & Surgery Non ST Elevation MI (NSTEMI) Suspected Acute Coronary Syndrome Antibiotics and the Kidney Acute Upper GI Bleeding (AUGIB) Pericardiocentesis Pleural Effusion Spontaneous Pneumothorax Acute Diarrhoea Iron Deficiency Anaemia Hyperthyroidism Gout Giant Cell Arteritis Pacemakers Clinical Suspicion PE – ACP Community Acquired Pneumonia (CAP) Management of Urinary Symptoms Management of Acute Kidney Injury SSRI Poisoning Immobility Autopsies Indications for Echocardiography Bradycardia Suspected Meningitis Hypernatraemia Diarrhoea – ACP Suspected Meningitis – ACP Blood Transfusion Brain Tumours Newer Antidiabetic Drugs Parkinson’s Disease Major Haemorrhage Protocols (DGRI & GCH) Major Haemorrhage Stroke Thrombolysis Heart Failure – ACP Suspected Anaphylaxis Anaphylaxis – ACP The AMB Score – ACP Transient Loss of Consciousness (TLOC) – ACP Bell’s Palsy – ACP Suspected Sepsis Lumbar Puncture Hypokalaemia Gentamicin Dosing Transient Loss of Consciousness Urinary Tract Infection Urethral Catheterisation Vancomycin Dosing Hyponatraemia Narrow Complex Tachycardia Hypocalcaemia New Onset Type 1 Diabetes – ACP Paracentesis for Tense Ascites – ACP Idiopathic Intracranial Hypertension – ACP Other Funny Turns Hypoglycaemia Hypoglycaemia – ACP Management of Transfusion Reactions Hypercalcaemia Haematemesis – ACP Anti-Platelet Therapy in Coronary Heart Disease Unfractionated Heparin Infusion Anaemia (Investigation) – ACP Delirium Suspected Seizure – ACP Headache – ACP Community Acquired Pneumonia – ACP Cellulitis Dyspepsia Management of Acute AF Rhythm Control in AF Atrial Fibrillation Renal Transplants Massive Pulmonary Embolism Head and Neck Injury Diabetic Ketoacidosis Switching from VRII Insulin Pumps Diabetes Mellitus Aspirin Digoxin Poisoning Tricyclic Antidepressants Opiates Benzodiazepines Gut Decontamination Deliberate Self Harm Acute Liver Failure Asymptomatic Raised Transaminases (ALT & AST) Nutritional Support in Adults Refeeding Syndrome Parenteral Nutrition Crohn’s Disease Acute Pancreatitis Abdominal Aortic Aneurysms Malignant Spinal Cord Compression Post Splenectomy Sepsis Ascites in Cirrhosis Alcohol Related Liver Disease Hepatitis C Symptom Control Suspected Variceal Bleeding Severe Headache Status Epilepsy in Adults Lower Gastrointestinal Bleeding Functional & Social Assessment Breathlessness with Abnormal CXR Polymyalgia Rheumatica Rheumatoid Arthritis Ureteric Colic & Renal Stones Intravascular Catheter Related Blood Stream Infection Care of Vascular Access Urinary Incontinence Peritoneal Dialysis Related Peritonitis The First Seizure Hypertension Ventricular Tachycardia Cardiogenic Shock Complicating Acute Coronary Syndrome Telemetry The Diabetic Foot Subcutaneous Insulin Diabetes and Acute Coronary Syndrome Hyperosmolar Hyperglycaemic State Multiple Sclerosis Coma
 
 
In this section Close
Home | Articles | Electrolyte Disturbances | Hypernatraemia

Hypernatraemia

Last updated 26th April 2024

Mechanisms

  1. Hypernatraemia is a state of hyperosmolality. It primarily occurs as a result of water deficit or, more rarely, sodium gain.
  2. Hypernatremia is uncommon because the ensuing rise in plasma osmolality stimulates the release of both ADH and thirst, thereby minimizing further water loss and increasing water intake.
  3. In adults, it is most often due to water losses in older patients that are not replaced because of impaired mental status

Causes

  1. Reduced water intake:
    • Commonest cause is insufficient water intake in elderly with cognitive impairment
    • Hypothalamic lesions impairing thirst or osmoreceptor function
  2. Free water losses:
    • Central or nephrogenic diabetes insipidus (now called ADH deficiency or resistance)
    • Osmotic diuresis eg glucose in uncontrolled diabetes mellitus
    • Insensible & sweat losses e.g. in fever, exercise, severe burns
    • Gastrointestinal losses
  3. Excess sodium intake or administration of hypertonic sodium solutions

Clinical Features

  1. Symptoms occur because water moves out of the brain (mirror image of hyponatraemia)
  2. Symptoms are uncommon in chronic hypernatraemia (the common form of hypernatraemia) and only likely if hypernatraemia is acute
  3. Symptoms of hypernatraemic dehydration include lethargy, weakness and irritability. If severe, manifestations can include seizures, and coma.

Investigations

  1. Check the drug list to make sure desmopressin hasn’t be inadvertently stopped- Untreated ADH deficiency ( formerly known as Diabetes Insipidus) has resulted in preventable deaths
  2. Full electrolyte panel with glucose, calcium, urea and creatinine to assess for presence of uncontrolled diabetes mellitus, other electrolyte abnormalities, renal impairment.
  3. Measurement of serum and urine osmolality may give further clue to cause.
  4. If urine osm < plasma osm, consider diabetes insipidus (ADH deficiency/resistance)
  5. If urine osm > plasma osm, pure volume depletion not due to diabetes insipidus eg inadequate water intake, GI or insensible losses.


General Management

  1. Treatment should address the underlying cause (e.g. stop offending medication or fluids, treat fever) as well as replacing any free water deficit.
  2. Fluid replacement strategy is based on severity, volume status (hypo, hyper or euvolaemic), and duration of hypernatraemia (chronic if >48 hrs or unknown, acute if <48 hrs)
  3. Nearly all patients with hypernatremia will have chronic hypernatraemia, even those who present with acute changes in mentation who are discovered to have hypernatremia.
  4. Acute hypernatraemia is uncommon, occurring in patients with salt poisoning; in patients with ADH deficiency (diabetes insipidus) who acutely lose the ability to replace their water losses (eg, a patient with ADH deficiency (diabetes insipidus) who undergoes surgery and does not receive adequate intravenous water).
  5. The key is regular monitoring of serum sodium and adjusting the fluids accordingly.

Fluid Replacement

  1. Mild cases of hypernatraemia – replace missing body water with oral water (not electrolyte drinks) or glucose 5% IV.
  2. Severe cases of hypernatraemia eg Na >170mmol/L, give glucose 5% IV unless the patient is volume depleted and hypotensive, in which case give sodium chloride 0.9% IV before water replacement.
  3. It is important that the rate of reduction of serum Na does not occur more rapidly than about 10mmol/L per day.
  4. Reassess and record patient’s blood results and clinical conditions every 8 hours. Recheck serum Na after 2 L of fluid replacement, or after 8 hours at the latest.
  5. Patients should be handed over to the next shift to clarify monitoring and fluid requirements.
  6. If diabetes is simultaneously present, then BM monitoring is required and if the blood glucose is >30mmol/L then follow the Hyperglycaemic Hyperosmolar Guideline
  7. In complex cases, the free water deficit can be calculated and advice can be sought from Biochemistry to guide the rate of water replacement.

What Rate of Infusion?

  1. In acute (<48 hrs) – 3-6ml/kg/hour, aiming to correct sodium to near normal values within 24 hours. If severe symptoms – correct sodium by 2mmol/l/hour in first few hours followed by correction rate of 0.5mmol/l/hour
  2. In chronic (>48 hrs or unknown duration) – 1.35ml/kg/hour, aiming to correct sodium no faster than 0.5mmol/l/hour or 10-12 mmol/l/day

Hypernatremia Due to Correction of Severe Hyperglycaemia

  1. Serum sodium rises because of osmotic shift of water from extracellular fluid into cells and because of loss of electrolyte-free water in the urine as excess glucose is excreted.
  2. Because most of these patients are hypovolemic and hyperglycaemic, free water is usually administered as saline 0.45% at 6-12ml/kg/hr rather than dextrose 5%.

Content by Tina Grant. Updated by Chris Isles.