Physical Examination
Myotonia:
Grip Myotonia: Difficulty in releasing the hand after a firm grip.
Perioral Myotonia: Prolonged contraction and slow relaxation of muscles around the mouth.
Percussion Myotonia: Sustained muscle contraction induced by tapping on a muscle belly, such as the thenar eminence.
Muscle Weakness:
Preferentially affects distal more than proximal muscles.
Notable in hands, feet, neck flexors, and facial muscles.
Muscle Wasting:
Visible in the temporalis, sternocleidomastoid, and distal limb muscles, often presenting a thin, wasted appearance.
Facial Muscle Involvement:
Bilateral ptosis.
Facial muscle weakness leading to a "hatchet face" appearance and diminished facial expressions (mask-like facies).
Gait Abnormalities:
A waddling gait may be evident due to hip muscle weakness.
Foot Drop: Weakness of the dorsiflexors of the foot, leading to challenges in foot clearance during walking.
Absence of Deep Tendon Reflexes:
Reflexes such as the bicep, tricep, and ankle jerk may be reduced or absent.
No Sensory Deficits:
Sensation generally remains intact, as myotonic dystrophy primarily affects the muscular system.
Additional Examination
Investigations
Management