Makindo Medical Notes

Ensure you have resuscitation facilities available before proceeding.

About

• The Edrophonium test is used in the diagnosis of Myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue.

Aetiology

• Edrophonium is a fast-acting anticholinesterase inhibitor that increases acetylcholine (ACh) levels in the synaptic cleft.
• This increase in ACh can temporarily improve muscle function in patients with Myasthenia gravis.
• Diagnosis may also involve testing for anti-acetylcholine receptor antibodies.

Clinical Presentation

• Patients typically exhibit fatigable weakness, particularly in the ocular, bulbar, and limb muscles.

Prior to Test

• Patient Consent: Obtain informed, verbal consent from the patient.
• Prepare IV Access: Ensure intravenous access is secured.
• Equipment Required: Have Atropine and resuscitation equipment readily available in case of adverse reactions.
• Monitoring: Cardiac monitoring is required due to potential effects on heart rate.

Test Procedure

• Muscle Assessment: Identify specific muscles to be tested, and involve a neutral observer to assist with objective assessment.
• Double-Blind Trial: Consider performing a double-blind test using both saline and Edrophonium to objectively assess the response.
• Initial Dose: Administer an initial dose of 2 mg of Edrophonium IV, and observe the response in the chosen muscle group.
• Further Dosing: Follow up with 8 mg of Edrophonium and compare the effect against saline to confirm response.
• Observation Period: The effect of Edrophonium typically lasts around 5 minutes; assess the muscle response within this period.

Side Effects and Management

• Bradycardia: Persistent or severe bradycardia may occur. Treat with Atropine if needed.
• Other Side Effects: Nausea, salivation, diarrhoea, and fasciculations (involuntary muscle twitching) may also occur.