BOF: 22
A 27-year-old female has been referred by her GP as he
suspects she has chronic fatigue syndrome.
On examination you note that she has a bilateral ptosis.
There is frontal balding and wasting of the facial muscles. There is wasting of
the masseter and temporalis muscles.
The sternocleidomastoid muscles are weak bilaterally.
On examination of her limbs there is grip myotonia and
percussion myotonia demonstrable in the thenar eminence.
There is weakness of the distal limb muscles.
The patient wishes to know what the chances are of this
condition being transmitted to her children.
Your reply would be:
a)
0%
b)
25%
c)
50%
d)
75%
e)
100%
Answer:
c)
The patient has bilateral ptosis which has multiple causes
(Page 480 ACES for
PACES)
Wasting of the facial muscles is seen in dystrophia
myotonica (Page 490 ACES for
PACES)
Wasting of the temporalis and masseters may occur in a few
conditions, one of them being myotonic dystrophy
(Page 493 ACES for PACES)
Bilateral weakness of the sternocleidomastoids may occur in
a few conditions one of them being dystrophia myotonica
(Page 499 ACES for PACES)
Grip myotonia and percussion myotonia occur in dystrophia
myotonica (Page 505 ACES for PACES)
Myotonic dystrophy usually affects the distal muscles of
the limbs (Page 434 ACES for PACES)
There are a few causes of myotonia
(Page 450 ACES for PACES). In association with wasting the diagnosis
is myotonic dystrophy. The fact that the patient has frontal balding is further
evidence in favour of this.
Myotonic dystrophy is inherited as an autosomal dominant
condition hence there is a 50% chance of a child being affected if a parent has
the condition.
Myotonic dystrophy is a multisystem disorder. The
other systems that may be affected are:
CVS conduction abnormalities, arrhythmias
GIT dysphagia, delayed gastric emptying, bile acid
malabsorption, small bowel bacterial overgrowth, raised liver enzymes,
gallstones
RS nocturnal hypoventilation
E&M diabetes mellitus
IS frontal balding
EYES cataracts
Last Updated: 09/04/06
