Arthritis

Trigger finger and tenosynovial disease

Multiple trigger finger - pathophysiology, diagnosis and treatment

15 questions 1 source pages

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Q1What is a tourniquet and what are its contraindications?▸

A temporary constrictive device to occlude blood flow to the extremities and create a bloodless field
Systemic contraindications: sickle cell anaemia, hypercoagulation
Local contraindications: skin problems, PVD (peripheral vascular disease), vascular graft

Q2How is a tourniquet applied?▸

Choose a site with no bony prominence; adequate padding
Width: widest possible but with sufficient distance from the joint (usually the diameter of the limb)
Length with 3-inch overlap (x1.5 circumference of the limb)
Tension: 2 fingers fit underneath

Q3What inflation pressure and duration are used for a tourniquet?▸

Upper limb: sBP + 50 mmHg
Lower limb: sBP + 100 mmHg
Latest concept: limb occlusion pressure (LOP) - the minimal pressure to completely occlude the artery
Duration <90 min, maximum 2 hours

Q4What are the complications of tourniquet use?▸

Q5What is Bier's block and what are its indications and contraindications?▸

LA injected into the local circulation/perivenously plus a tourniquet to prevent entry into the systemic circulation
Contraindicated if unable to perform Esmarch, LA allergy, severe HT, compartment syndrome, uncooperative or obese patient
Good in tenolysis

Q6How is a Bier's block performed?▸

Preparation: emergency trolley, IV access at the contralateral limb, BP/cardiac/SpO2 monitoring
Double-cuff tourniquet of appropriate size with padding; IV access to the operative limb
Elevation + Esmarch for exsanguination
Inflate the proximal cuff to 100 mmHg above sBP, then inject LA slowly
Change cuff at 30 minutes or when tourniquet pain occurs - inflate distal and deflate proximal
Deflate after >=20mins, max <90mins

Q7What is the maximum dose of local anaesthetic in a Bier's block?▸

LA maximum 3 mg/kg (with adrenaline 7 mg/kg)
1% lignocaine, slow injection, onset <=5 minutes
Dilution example: 1% lignocaine diluted to 10 ml = 0.5% lignocaine, x4 =40ml; 40 ml 0.5% lignocaine = 200 mg

Q8What is the mechanism of action of local anaesthetics?▸

Most are sodium-gated voltage channel blockers
Prevent depolarisation of the nerve cell and propagation of the action potential

Q9Compare amide and ester local anaesthetics.▸

Amide: metabolised by the liver, excreted in urine; longer acting (e.g. lignocaine, bupivacaine)
Ester: metabolised by plasma and tissue fluid cholinesterase, excreted in urine (e.g. cocaine)

Q10What is the order of nerve fibre blockade by local anaesthetics?▸

Q11What are the properties of lignocaine?▸

Q12Which steroid preparation and dose are used for trigger finger/1st CMCJ OA and what are the side effects?▸

Usual preparation: methylprednisolone 20 mg/40 mg per ml
Trigger finger / 1st CMCJ OA: 20 mg methylprednisolone + 5 mg lignocaine
Side effects: fat atrophy, pigmentation change, tendon/ligament damage

Q13What is the paediatric dose of midazolam (benzodiazepam)?▸

Q14What is the dose of chloral hydrate sedation?▸

Q15What aspects of multiple trigger finger does the source ask about?▸

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