Monday, April 25, 2011

Flail arm and flail leg variants of ALS

Neurology 2009; 72: 1087-1094

These are phenotypic variants of ALS that have been described a century or more ago that have unique characteristics including

1.  In flail arm, proximal wasting and weakness, in flail leg, distal weakness or wasting
2.  LMN variant with no clonus, hypertonia or UMN signs, or involvement of other extremity (leg +  arm) or bulbar involvement
3.  4:1 male predominance in FA, 1:1 gender equality in FL in London; 10:1 and 5:1 respectively in Melbourne series
4.  Relatively longer prognosis than other forms of ALS with lifespan of around 6 years

Synonyms FA:  Vulpian-Bernhardt syndrome, hanging arm syndrome, neurogenic man in a barrel syndrome, or amyotrophic brachial diplegia
Synonyms FL: Marie -Patrikios variant, pseudopolyneuritic variant of ALS, peroneal form of ALS

Delayed cerebral thrombosis after initial good recovery from pc meningitis

Schut ES, Brouwer MC, de Gan J, Florquin S, et al.  Neurology 2009; 73: 1988-1995.

Dutch authors have small case series of patients who recovered apparently from meningitis then developed stroke on a delayed basis 2-3 weeks after recovery.  6 patients, including 5 males 30-73 got dexamethasone for pneumococcal meningitis.  After 7-19 days  patients suddenly deteriorated with headache, fever, loss of consciousness, brainstem signs and had thalamic or brainstem strokes in penetrating artery territory.  LP's were sterile. 
In discussion, authors note they surveyed a similar population in the predexamethasone days and found no delayed strokes.  Authors speculate that withdrawing corticosteroids may be compromising and suggest reinstating high dose steroids in these patients, as well repeating LP promptly, treating with antibiotics again, and checking for endocarditis.

Saturday, April 23, 2011

treatment of photosensitive seizures

Take Home Points
• Light-induced seizures are not uncommon.
• Most patient with epilepsy can safely watch
television or play video games (using easy
preventive measures in those who are lightsensitive).
• Blue sunglasses can be very effective (and
documented with EEG & photic stimulation).
• Valproate & levetiracetam are the two most
effective treatments currently available, and the
drug selection for a given epilepsy syndrome
should consider if photosensitivity is present.
• Follow-up EEG with photic stimulation is helpful to
access the patient's response to treatment.

photosensitive seizures

• 4.1 to 8.9% prevalence of photosensitivity
(without other seizures) in population
- 49% television induced
- 43% video game induced
• 76% of children with photosensitive
seizures to Pokemon had never had a prior
seizure, and 90% of these did not go on to
develop seizures.
• Broadcasting guidelines have dramatically
decreased photosensitive seizures
Takahashi Y et al. Neurology, 2004; 62: 990-993.

Epilepsy Syndromes Associatedwith Photosensitivity

Epilepsy Syndromes Associated
with Photosensitivity

– Benign myoclonic epilepsy in infancy
– Severe myoclonic epilepsy of infancy (Dravet Syndrome)
– Myoclonic-astatic epilepsy (Doose Syndrome)
– Childhood absence & juvenile absence (13-18%)
– Juvenile myoclonic epilepsy (30-35%)
– Epilepsy with GTC seizures on awakening (13%)
– Primary reading epilepsy (<10%)
– Jeavons syndrome (eyelid myoclonia and absences)
– Progressive myoclonic epilepsies (NCLFs, Lafora's
disease, Unverricht-Lundborg disease, MERRF)
– Idiopathic photosensitive occipital lobe epilepsy.
Guerrini R, Genton P. Epilepsia, 2004; 45 (Suppl 1): 14-18.
Photosensitivity: Types of
Seizures Induced
• Prevalence based on the literature:
– GTC (55-84%)
– Absences (6-20%)
– Myoclonic jerks (2-8%)
– Focal seizures (2.5%)
• Reports may over-exaggerate GTCs in
relation to "minor" seizure events.
• Clinical experience: Myoclonic jerks >
absences > GTCs.
Panayiotopoulos C. Epileptic Syndromes and Their Treatment. Springer. London 2009.
Photosensitivity Historical Timeline
1885 Gowers described girl with seizures when going into
bright sunlight
1932 Radovici described eyelid myoclonias and absence
seizures in response to eyelid closure while looking
at bright light
1952 Livingston reported TV-induced seizures for 1st time
1962 Gastaut studied 35 patients with TV induced
1981 Rushton reports "Space-Invader epilepsy"
1993 TV commercial caused 3 seizures in UK. Guidelines
for photic stimulation in commercials introduced.
1997 Pokemon Episode (Pikachu) induced seizures in
560 Japanese children.

Aggravation of Severe Myoclonic Epilepsy (SMEI) by Lamotrigine

v Twenty-one SMEI patients (age 2-18 years, mean
9 years)

v Convulsive seizures increased by >50% in 8 of 20
pts, myoclonic seizures worsened in 6 of 18 pts.

v Of 5 pts with improvement in one seizure type, 4
had concomitant worsening of more disabling

v Lamotrigine was withdrawn in 19 pts, with
consequent improvement in 18
R. Guerrini et al, Epilepsia 1998;39, 508-12

myoclonus fromgabapentin

Myoclonus Associated with the Use of Gabapentin

v Of 104 consecutive patients treated with
gabapentin, 13 (12.5%) developed myoclonus
v All patients (age 14 to 41 years) had refractory
partial epilepsy, 6 had a static encephalopathy
v Myoclonus was multifocal in 10, contralateral to
the epilepticus focus in 3
v Myoclonus persisted for as long as gabapentin
was continued. Disappeared on drug withdrawal.
v An EEG recording in 3 patients showed no
J. Asconapé et al., Epilepsia 2000:41:479-82