| Download the amazing global Makindo app: Android | Apple | |
|---|---|
| MEDICAL DISCLAIMER: Educational use only. Not for diagnosis or management. See below for full disclaimer. |
Tensilon test
⚠️ About
- The Edrophonium (Tensilon) test is used in diagnosing Myasthenia Gravis (MG), a neuromuscular junction disorder marked by muscle weakness and fatigability.
- Edrophonium is a short-acting anticholinesterase inhibitor → increases acetylcholine (ACh) in the synaptic cleft → temporary improvement in muscle strength in MG.
- Diagnosis today often relies more on anti-ACh receptor antibody testing and electrophysiology, but this test remains an important teaching point.
🧪 Aetiology / Mechanism
- Edrophonium blocks acetylcholinesterase → prevents ACh breakdown → boosts neuromuscular transmission.
- In Myasthenia Gravis (autoimmune anti-AChR antibodies), this temporarily overcomes receptor blockade.
- Also useful in differentiating myasthenic vs cholinergic crisis (historically).
👀 Clinical Presentation of MG
- Fatigable weakness (improves with rest, worsens with exertion).
- Commonly affects:
- Ocular muscles → ptosis, diplopia
- Bulbar muscles → dysarthria, dysphagia
- Limb muscles → proximal weakness
📋 Preparation Before Test
- Consent: Explain risks, short effect, and monitoring.
- IV access: Secure before starting.
- Resuscitation facilities: Have atropine drawn up (0.6 mg IV) and cardiac monitoring in place.
- Baseline muscle test: Agree on one muscle group (e.g., eyelid, neck flexion) with an observer.
✅ Test Procedure
- Step 1: Administer 2 mg IV Edrophonium (test dose) → observe 30 sec for adverse events.
- Step 2: If safe, give 8 mg IV → total 10 mg maximum.
- Step 3: Watch for immediate, short-lived (≈5 min) improvement in strength (e.g., ptosis resolves).
- Optional: Perform double-blind with saline to reduce bias.
⚠️ Side Effects & Management
- Bradycardia / Asystole: Treat with Atropine IV.
- Other: Nausea 🤢, salivation 💧, abdominal cramps, diarrhoea, fasciculations.
- Monitor for at least 10 mins post-test for delayed reactions.
💡 Key Teaching Pearls
- MG shows rapid, reproducible response → confirms neuromuscular junction pathology.
- AChE inhibitors are diagnostic (Edrophonium) and therapeutic (Pyridostigmine).
- Modern diagnosis often uses antibody assays & EMG, but the Edrophonium test illustrates the pathophysiology beautifully.
| The content on this website is provided for educational and informational purposes only to support exam preparation (e.g., MLA, MRCP, USMLE) and learning. This is NOT medical advice, diagnosis, treatment, or professional guidance. It does not replace consultation with a qualified healthcare professional, official guidelines (e.g., NICE, GMC, BNF), or supervised clinical practice. Always verify information with current, authoritative sources. Makindo and its contributors accept no liability for any reliance on this content, including errors, omissions, or any resulting harm, loss, or consequences. By using this site, you agree to these terms. |
|
|
Categories
- A Level
- About
- Acute Medicine
- Anaesthetics and Critical Care
- Anatomy
- Anatomy and Physiology
- Biochemistry
- Book
- Cardiology
- Collections
- CompSci
- Crib Sheets
- Crib sheets
- Dental
- Dermatology
- Differentials
- Drugs
- ENT
- Education
- Electrocardiogram
- Embryology
- Emergency Medicine
- Endocrinology
- Ethics
- Foundation Doctors
- GCSE
- Gastroenterology
- General Practice
- Genetics
- Geriatric Medicine
- Guidelines
- Gynaecology
- Haematology
- Hepatology
- Immunology
- Infectious Diseases
- Infographic
- Investigations
- Lists
- Mandatory Training
- Medical Students
- Microbiology
- Nephrology
- Neurology
- Neurosurgery
- Nutrition
- OSCE
- OSCEs
- Obstetrics
- Obstetrics Gynaecology
- Oncology
- Ophthalmology
- Oral Medicine and Dentistry
- Orthopaedics
- Paediatrics
- Palliative
- Pathology
- Pharmacology
- Physiology
- Procedures
- Psychiatry
- Public Health
- Radiology
- Renal
- Respiratory
- Resuscitation
- Revision
- Rheumatology
- Statistics and Research
- Stroke
- Surgery
- Toxicology
- Trauma and Orthopaedics
- USMLE
- Urology
- Vascular Surgery