Saturday, April 27, 2013
Tuesday, March 26, 2013
Thursday, January 17, 2013
Bilateral Internuclear Ophthalmoplegia in Multiple Sclerosis
A 45-year-old man with multiple sclerosis presented with worsening
weakness in his right leg and double vision. Neurologic examination
revealed horizontal diplopia during lateral gaze in both eyes. The
patient had an adduction deficit in the right eye and nystagmus in the
left eye on leftward gaze (Panel A). He also had an adduction deficit in
the left eye and nystagmus in the right eye on rightward gaze (Panel
B). Upward gaze (Panel C), downward gaze (Panel D), and normal primary
position (Panel E) were unremarkable.
Internuclear ophthalmoplegia is characterized by impaired horizontal
eye movement that is caused by a lesion in the medial longitudinal
fasciculus, a fiber tract that rises from the abducens nucleus in the
pons to the contralateral oculomotor nucleus in the midbrain. Lesions in
the medial longitudinal fasciculus result in the failure of adduction
on attempted lateral gaze. Any brain-stem syndrome can interrupt the
medial longitudinal fasciculus and result in impaired horizontal eye
movement, but the most frequent underlying cause is multiple sclerosis.
This patient had internuclear ophthalmoplegia in both eyes due to
demyelinating lesions. Glucocorticoids were administered intravenously,
but the deficits did not resolve. On follow-up at 2 months, the
patient's gait had improved, but the internuclear ophthalmoplegia
remained.
Friday, December 14, 2012
Thursday, December 6, 2012
Chvostek's and Trousseau's Signs
A 38-year-old man presented to the emergency department with facial paresthesias and upper-extremity muscle cramping. His symptoms were progressive, beginning as mild paresthesias on postoperative day 1 by the time he presented, they had been getting worse for about 24 hours. His medical history was noteworthy only for papillary thyroid carcinoma, for which he had undergone a total thyroidectomy 2 days earlier. Physical examination revealed apparent Chvostek's sign (Figure 1A and Video 1) and Trousseau's sign (Figure 1B and Video 2), a result of postsurgical acquired hypoparathyroidism. His total calcium level was 5.8 mg per deciliter (normal range, 8.4 to 10.3) (1.45 mmol per liter [2.1 to 2.6]), his free calcium level was 1.68 mEq per liter (normal range, 2.24 to 2.64) (0.84 mmol per liter [1.12 to 1.32]), and his serum phosphate level was 6.6 mg per deciliter (normal range, 2.7 to 4.5) (2.13 mmol per liter [0.87 to 1.45]). The parathyroid hormone level was 7 pg per milliliter (normal range, 15 to 65).
Monday, October 15, 2012
Gradenigo syndrome
A 28-year-old woman presented with fever, double vision, and facial pain. Neurologic examination showed neck stiffness, pain
in the distribution of the right trigeminal nerve, and right abducens palsy (figure 1). Tympanic membranes were normal. MRI revealed sphenoid sinusitis, basilar pachymeningitis, and clivus osteomyelitis (figure 2). CSF analysis showed pleocytosis, increased protein contents, decreased glucose levels, and positive cultures for Staphylococcus aureus.
The triad of suppurative otitis media, pain in the distribution of the
trigeminal nerve, and abducens palsy is called Gradenigo
syndrome.1 While it most often affects children, it may occur in adults and may rarely present without otitis media.2 While bone compromise is usually confined to the petrous apex, it may extend to sphenoid sinuses, clivus, and basal meninges.
Figure 2 Head MRI
Contrast-enhanced
T1-weighted MRI of the head shows mucosal thickening of sphenoid sinuses
(arrowheads), basilar and right
middle fossa pachymeningitis (small arrows), and
osteomyelitis of the clivus (large arrow). While the right abducens
nerve
is not well visualized, it could be inferred in
the axial sections (upper row) that it is entrapped throughout the
Dorello
channel and the cavernous sinus.
Sunday, September 16, 2012
Acute Adie syndrome
Parasympathetic denervation of the iris sphincter muscle in Adie
syndrome results in an enlarged tonic right pupil reacting
poorly to light (A, B). Near response was also
impaired (C). It is supersensitive to cholinergic agents (pilocarpine
0.1%)
(D). Paralysis of the iris results in
characteristic segmental vermiform movements. These are visible
superolaterally acutely
and inferomedially 6 months later
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