Improving recognition of Duchenne muscular dystrophy: a retrospective case note review

Abstract

Background: Over the last 30 years, there has been little improvement in the age of diagnosis of Duchenne muscular dystrophy (DMD) (mean age of 4.5-4.11 years).

Aim: To review the diagnostic process for DMD in boys without a family history in order to identify where delays occur and suggest areas for improvement.

Design: A retrospective case note review.

Setting: A tertiary centre for neuromuscular diseases in England.

Patients: All boys without family history diagnosed with DMD in the last 10 years (n=20).

Outcome measures: Mean age at four key steps in the diagnostic pathway of DMD.

Results: (1) Age at first reported symptoms of DMD was 32.5 (8-72) months (2.7 years). (2) First engagement of a healthcare professional was at 42.9 (10-90) months. (3) Creatine kinase (CK) levels were checked at 50.1 (14-91) months. (4) Diagnosis of DMD was confirmed at 51.7 (16-91) months (4.3 years). The total delay from parental concern to diagnosis was 19.2 (4-50) months (1.6 years).

Conclusions: Our study shows an improvement in the age of diagnosis of DMD although there continues to be a delay in presentation to a health professional and a delay in obtaining a CK test. To reduce these delays, we propose screening for DMD as part of the Child Health Surveillance Programme, in addition to lowering the threshold for CK testing in primary care by promoting a new DMD mnemonic MUSCLE. An earlier diagnosis of DMD will allow timely access to genetic counselling, standards of care and clinical trials.

Keywords: Duchenne muscular dystrophy; Paediatrics; creatine kinase; developmental delay; diagnosis.

Figure 1

Display of individual delays in diagnostic pathway Duchenne muscular dystrophy (DMD). The X-axis displays each individual boy (n=20). The Y-axis represents the total delay (in months) for each boy from first reported symptoms (time 0 on Y-axis) to diagnosis. This total delay is divided into three parts. The blue part of the column is the delay from first reported symptoms to visiting a health professional (Symp-HP), the red part is the delay from visiting a health professional to the creatine kinase test (HP-CK) and the green part is the delay between CK test and the diagnosis of DMD (CK-Diagn).

Figure 2

Duchenne muscular dystrophy (DMD) screening mnemonic MUSCLE. The mnemonic illustrates the main features of DMD and stresses the importance of early creatine kinase (CK) testing.