Local anaesthetic failure in joint hypermobility syndrome

When taking biopsies to assess skin strength in Ehlers–Danlos syndrome type III (EDS–III), a Danish group noticed that the patients experienced much pain despite conventional local anaesthesia.¹ When asked, all these patients reported previous experience of partial or complete failure of local anaesthesia in dental or obstetric procedures—for which reason some had been dismissed as hysterics. Pursuing this finding, Arendt-Nielsen et al.² compared the effects of local anaesthesia in 8 patients with EDS–III and 8 controls. Although the patients did gain analgesia from intradermal lidocaine the duration of effect was much shorter than in controls. EDS–III (now known as EDS–hypermobility type) is regarded by many authorities as identical to joint hypermobility syndrome (JHS).^3,4 We wish to draw attention to the possibility of resistance to local anaesthesia in individuals with this common and under-diagnosed condition.

Box 2 Five-part questionnaire for identifying hypermobility (Ref. ⁷) Answers in the affirmative to 2 or more questions suggest hypermobility with sensitivity 80–85% and specificity 80–90%

• Can you now (or could you ever) place your hands flat on the floor without bending your knees?

• Can you now (or could you ever) bend your thumb to touch your forearm?

• As a child did you amuse your friends by contorting your body into strange shapes OR could you do the splits?

• As a child or teenager did your shoulder or kneecap dislocate on more than one occasion?

• Do you consider yourself double-jointed?

Box 3 Brighton criteria for joint hypermobility syndrome (JHS) (Ref. ⁸) JHS is diagnosed in the presence of two major criteria, or one major and two minor criteria, or four minor criteria. Two minor criteria will suffice where there is an unequivocally affected first-degree relative.

Major

• Beighton score of 4 out of 9, or more (either currently or historically)

• Arthralgia for longer than 3 months in four or more joints

Minor

• A Beighton score of 1, 2 or 3 out of 9 (0, 1, 2 or 3 if aged 50+)

• Arthralgia in 1–3 joints, or back pain or spondylosis, spondylolysis/spondylolisthesis

• Dislocation in more than one joint, or in one joint on more than one occasion

• Three or more soft tissue lesions (e.g. epicondylitis, tenosynovitis or bursitis)

• Marfanoid habitus (tall, slim, arm span >height, arachnodactyly)

• Skin striae, hyperextensibility, thin skin or abnormal scarring

• Eye signs: drooping eyelids, or myopia, or anti-mongoloid slant

• Varicose veins, or hernia, or uterine/rectal prolapse

Many normal people have hypermobile joints and medical diagnosis of the medical syndrome requires symptoms—which can include chronic pain, impairment of proprioception, and temporomandibular joint dysfunction (a manifestation of which dentists may be unaware).⁵ JHS is overrepresented in general rheumatology clinic populations and in our experience (RG and AJH)⁶ many of these patients report failure of local anaesthetics. This matter was addressed briefly in a paper published in 2003.⁷ A questionnaire was completed by 172 female Caucasian JHS patients, 53 non-hypermobile age-matched controls, and 28 individuals who showed evidence of hypermobility with insufficient features to qualify for JHS (HM-sine-JHS) as defined by the Brighton criteria.⁸ We asked ‘If you have ever had a local anaesthetic injection (dentist/minor surgery/epidural), did you think that it was as effective as it should have been?’. 58% of JHS patients, 21% of controls and 14% of the HM-sine-JHS group answered in the negative. For JHS versus controls the odds ratio was a highly significant 2.85. Although the question was simplistic, non-exploratory, and reliant on recall and selfperception, the difference between JHS and controls was striking. Neither group had knowledge of any study hypothesis. At the time there was nothing of this nature documented in patient information sheets or published research.

We suspect that in many people JHS goes unrecognized. So, how can a busy clinician, mindful of possible resistance to local anaesthesia, make the diagnosis? There are two easy methods for identifying hypermobility—carry out a Beighton score⁹ (Box 1); or ask the patient to answer a five-part screening questionnaire⁷ (Box 2). The phenotype is shown in Box 3.

Box 1.

The nine-point Beighton hypermobility score (Ref. ⁹) One point may be gained for each side for manoeuvres 1–4 so that the hypermobility score will have a maximum of nine points if all are positive. A score of ≥4/9 indicates widespread hypermobility

Ability to:
	Left	Right
Passively dorsiflex the fifth metacarpophalangeal joint to ≥ 90°	1	1
Oppose the thumb to the volar aspect of the ipsilateral forearm	1	1
Hyperextend the elbow to ≥ 10°	1	1
Hyperextend the knee to ≥ 10°	1	1
Place hands flat on the floor without bending the knees	1
Total	9

Although the pathophysiology of this phenomenon remains unresolved, an important clue that a patient is at risk of local anaesthetic failure might be in front of our eyes.