[Quantitative evaluation of pseudohypertrophy in Duchenne muscular dystrophy]

Area of Science:

• Biomedical Engineering
• Clinical Medicine
• Pediatric Neurology

Background:

• Pseudohypertrophy of the calves is a hallmark sign in Duchenne muscular dystrophy (DMD).
• Quantitative assessment of this pseudohypertrophy is crucial for monitoring disease progression and treatment efficacy.
• Previous methods using simple calf circumference measurements have shown limitations due to variability related to nutritional status.

Purpose of the Study:

• To establish a reliable quantitative method for evaluating calf pseudohypertrophy in Duchenne muscular dystrophy.
• To identify the most informative anthropometric ratio for assessing calf enlargement in DMD.

Main Methods:

• Measurements of thigh, knee, calf, and ankle circumferences were taken.
• Data collected from 7 patients with DMD (ages 3-5 years) and 165 healthy boys (ages 3-6 years).
• Various circumference ratios were analyzed, with a focus on calf circumference relative to other limb segments.

Main Results:

• Simple calf circumference was not a reliable indicator of pseudohypertrophy in DMD due to nutritional influences.
• The calf/knee circumference ratio emerged as the most informative measurement.
• 13 out of 14 affected legs in DMD patients showed calf/knee circumference ratios above the mean + 2 standard deviations of the control group.

Conclusions:

• The calf/knee circumference ratio offers a quantitative and reliable method for assessing calf pseudohypertrophy in Duchenne muscular dystrophy.
• This ratio can aid in the objective evaluation of disease manifestation in young DMD patients.
• Further validation of this anthropometric marker in larger cohorts is warranted.