BOF: 3.26
You are called to see a
patient in the surgical ward. He is recovering from surgery. He has had
emergency surgery for dissecting aneurysm of the descending aorta. The
postoperative period was complicated by pneumonia and pseudomembranous
colitis. He has been transferred from the ITU to the surgical wards two days
prior to you been called to see him. The patient is not moving his right lower
limb normally and the surgical registrar thinks he may have had a stroke.
On examination, the patient
is conscious and alert and has no abnormality in relation to speech. His
cranial nerves are intact and there is no neurological deficit in the upper
limbs. On examination of his lower limbs there is weakness of dorsiflexion and
eversion of his right foot and there is weakness of toe extension. Sensation
is impaired over the lateral aspect of the right lower leg and over the dorsum
of the right foot.
The lesion in this patient
is:
a)
Anterior spinal artery thrombosis
b)
Lacunar infarction of the left internal capsule
c)
Femoral nerve palsy
d)
Tibial nerve palsy
e)
Common peroneal nerve palsy
Answer: e)
A compression neuropathy of
the common peroneal nerve may occur after prolonged bed rest. Associated loss
of weight with reduction in the size of the protective fat pad may also
contribute.
Anterior spinal artery
thrombosis would result in paraparesis and a characteristic pattern of sensory
loss, bilateral loss of pain and temperature sensation with preserved joint
position sense and vibration sense
ACES for PACES page 452, 453
Lesions of the internal
capsule would result in hemiparesis or hemiplegia
ACES for PACES page 451
Revision Tip
Revise the features of
femoral nerve palsy and tibial nerve palsy
ACES for PACES page 518,519
