Intended for healthcare professionals

Endgames Case Review

A case of unusual hand pain in general practice

BMJ 2015; 351 doi: https://doi.org/10.1136/bmj.h5005 (Published 25 September 2015) Cite this as: BMJ 2015;351:h5005
  1. Faraz Mughal, general practitioner speciality trainee year 31,
  2. Ahmed Rashid, National Institute for Health Research academic clinical fellow2,
  3. Rajnish C Mishra, general practitioner1
  1. 1Dove Medical Practice, Birmingham B23 5DD, UK
  2. 2Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
  1. Correspondence to: F Mughal farazm{at}doctors.org.uk

A 34 year old white man presented to his general practitioner with a one year history of progressive bilateral hand pain. There was no trauma history or previous arthropathy. He consumed 84 units of alcohol a week, lived alone, and had lost his job as a plasterer owing to reduced hand function. He had three children. On initial examination of the hands and wrists, he had no swelling or bony tenderness and he had normal power, reflexes, and sensation of the upper limbs. Pain was elicited when he unclenched his fists.

Vitamin supplements were prescribed, he was referred to the alcohol team, and a fit note was issued with review planned after a full set of blood tests. Full blood count, renal profile, bone profile, thyroid function, erythrocyte sedimentation rate, and C reactive protein were within normal ranges. Serum alanine aminotransferase was raised (59 U/L; reference range 0-40) and rheumatoid factor was negative.

At follow-up review, bilateral ptosis, frontal balding, and myopathic facies were noted. Bilateral percussion myotonia and distal wasting of the hand muscles were also found on examination. Finger extension was restricted and slowed bilaterally. Cranial nerve examination was otherwise normal, as was cardiorespiratory examination.

Questions

  • 1. What do these clinical findings suggest?

  • 2. On the basis of these clinical findings, what further investigations are indicated in general practice?

  • 3. Should this patient be referred for specialist input?

  • 4. How should the patient be counselled after confirmation of the diagnosis?

Answers

1. What do these clinical findings suggest?

Short answer

These clinical findings suggest a diagnosis of muscular dystrophy, probably myotonic dystrophy.

Discussion

Myotonic dystrophy is characterised by progressive myopathy, myotonia, and systemic involvement. Myotonic dystrophy type 1 (DM1), known as Steinert’s disease, is the most common type of muscular dystrophy in adults, with a European prevalence of 3-15 per 100 000. Myotonic dystrophy type 2 (DM2), known as proximal myotonic myopathy, is more rare and associated with later onset of symptoms and a milder phenotype.1 2

Ptosis, frontal balding, and myopathic facies (wasting and weakness of the facial muscles, seen in people with myopathies and myasthenia gravis) are present in both DM1 and DM2, but more so in DM1. Presence of percussion myotonia (failure of muscle relaxation resulting in sustained contraction of the thenar eminence on percussion with a tendon hammer) and wasting of the hand muscles support a diagnosis of DM1 over DM2.2

The inability to extend the fingers quickly is known as handgrip myotonia and is less common than percussion myotonia. Muscle pain, although uncommon, can occur in both DM1 and DM2 and may be seen when unclenching a fist.2

The patient’s myopathic facial appearance was not noticed at first presentation, but was identified at follow-up. Pattern recognition of clinical features is a key component of decision making and diagnosis in general practice. The lack of previous exposure to myopathic features may explain why the myopathic facies were missed at initial presentation.

Signs specific to myotonic dystrophy include handgrip and percussion myotonia. The features of myotonic dystrophy are subtle and can be easily overlooked in general practice. This case highlights the challenge of dealing with uncertainty in diagnosis and management under the “10 minute” time pressure while maintaining patient safety and quality of care. Using time as a diagnostic aid and arranging appropriate follow-up can be helpful management tools, as this case shows. A fresh perspective, the opportunity for reflection and further research, and advice from colleagues may also be useful, particularly when dealing with uncommon presentations in general practice.

Learning points for general practice:

  • An unusual symptom (such as pain on extension of the fingers) should always trigger reflection, further reading, and discussion with colleagues

  • If localised weakness is found on examination, look for generalised weakness

  • A myopathic facial appearance warrants consideration of several differential diagnoses

  • Handgrip myotonia, most commonly seen and felt after attempting to release your hand after shaking hands with the patient, is a salient feature of myotonic dystrophy.

2. On the basis of the clinical findings, what further investigations are indicated in general practice?

Short answer

Urine dipstick, electrocardiography (ECG), and serum creatine kinase should be performed in suspected myotonic dystrophy.

Discussion

A urine dipstick may show glycosuria. The risk of diabetes is not increased in DM1, but the skeletal muscle defect gives rise to an unusual form of insulin resistance.3 ECG may detect a prolonged PR interval, a wide QRS complex, and arrhythmias—cardiac abnormalities that contribute to the morbidity and mortality in DM1.4 Serum creatine kinase can be raised in patients with DM1, but it is usually normal in asymptomatic patients.2

3. Should this patient be referred for specialist input?

Short answer

Refer to neurology to confirm the clinical impression and to a clinical geneticist as needed. Further multidisciplinary input may be required.

Discussion

A neurology assessment will confirm the likelihood of myotonic dystrophy, and genetic analysis can confirm the diagnosis. Myotonic dystrophy is caused by autosomal dominant nucleotide repeat expansions. In DM1, a (CTG) expansion is present in the dystrophia myotonica protein kinase (DMPK) gene, which encodes myosin in skeletal muscle.1 Drugs aimed at reducing myotonic symptoms, such as mexiletine and phenytoin, can be started in secondary care.

People with DM1 can experience excessive tiredness and daytime sleepiness. Overnight sleep studies conducted by the respiratory team can help to exclude obstructive sleep apnoea. Spirometry can predict which patients will develop neuromuscular respiratory failure, so a respiratory referral is important.2

A 10 year mortality study found that conduction block defects and tachyarrhythmias cause 12-33% of deaths in DM1.5 Resting ECG can identify conduction abnormalities. Electrophysiological studies can help assess the risk of developing arrhythmias and the potential need for pacing or the insertion of an implantable cardioverter defibrillator. A severe abnormality on ECG (prolonged PR interval, wide QRS complex, second or third degree heart block, or non-sinus rhythm) combined with a diagnosis of atrial tachyarrhythmia predict sudden death in patients with DM1. This therefore warrants a cardiology referral.2 6

Referral to physiotherapy services can provide exercise therapy, support in the treatment of respiratory failure, and advice on the need for joint orthoses. Occupational therapy can help to improve hand function and enhance safety in the home. A clinical nurse specialist in muscle disease can be a vital part of the multidisciplinary team, acting as the link between primary and secondary care and enabling consistency in monitoring of the patient. Speech and language therapy may be needed if there are concerns about swallowing difficulties, and social workers can provide crucial support in late stage disease.2

4. How should the patient be counselled after confirmation of the diagnosis?

Short answer

Initial counselling should explain the mode of inheritance, possible complications, and implications for offspring. This may have occurred in secondary care but should be re-enforced in general practice with an opportunity to ask questions. Also discuss disease monitoring, the role of the multidisciplinary team, social support, and mental health screening.

Discussion

The autosomal dominant mode of inheritance in DM1 should be explained to the patient alongside a recommendation for further genetic input. This is made particularly important by the phenomenon of anticipation, whereby disease severity increases and age of onset decreases in successive generations. This may lead to earlier onset of a more severe form, such as congenital DM1. The patient should be informed about the potential complications that can arise. Testicular atrophy can result in infertility so fertility testing and relationship counselling should be offered.2 Yearly serum glucose and ECG monitoring in general practice should be undertaken. Cataracts, gastrointestinal symptoms, and skin problems are further complications that can occur and require active monitoring. The use of a patient “care card” can be discussed because ownership of one has been shown to improve disease monitoring.2

A holistic approach in the management of the patient enables the physical, psychological, and social health determinants to be explored and dealt with, enhancing the patient’s wellbeing. The purpose and importance of a multidisciplinary team approach in the management of DM1 should be explained to the patient. Education about symptoms that affect the quality of life—fatigue, limitations in mobility, impaired sleep, and daytime sleepiness—need to be communicated, with avenues for continued support for the patient and family outlined.7 Screening for anxiety and depression is important because quality of life can be severely impaired. In one study, 40% of patients with myotonic dystrophy reported screening scores suggestive of depression.8 Patients may also require guidance on social and employment support as well as information on support groups (such as the Myotonic Dystrophy Support Group (www.myotonicdystrophysupportgroup.org). Finally, the importance of regular follow-up with secondary care specialists should be emphasised because serious complications may develop at a later stage.

Patient outcome

The patient was started on gabapentin in the community and is under annual neurology review. He has been discharged from respiratory care after normal lung function and sleep study tests. He is drinking much less but is still out of work and finding it difficult to cope with his symptoms and how they restrict his ability to work. He and his family are due to receive specialist genetic counselling and further social input.

Notes

Cite this as: BMJ 2015;351:h5005

Footnotes

  • Competing interests: We have read and understood BMJ policy on declaration of interests and declare the following interests: none.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References

View Abstract

Log in

Log in through your institution

Subscribe

* For online subscription