Brain WM Disease

Question 1

Main DD for WM disease (group)

Answer 1

-V- vascular:
Small vessels disease
CADASIL

-Infectious
HIV
Lymes
JV virus

-Toxic
Carbon monoxide
Methotrexate, heroin
RT

-Autoimmune
MS
NMO
ADEM

Metabolic
Osmotic

Neoplastic
Congenital

Question 2

Osmotic demyelination,
Definition, path, risk factors

Answer 2

Acute osmotic demyelinating syndrome secondary to rapid elctrolyte disturbance/osmolarity imbalance.
Most commonly seen in rapid correction of hyponatremia.

Lesion to oligodendrocytes.
No inflammation.
Neuron-axons preserved.
All lesion are of same stage (synchronimus, monophasic)
Intracellular edema.

Risk factors:
Malnutrition (OH, malnutrition)
Chronic disease (liver, lung, renal)
Other: burn, transplant

Question 3

Osmotic Demyelination,
Morph, Dx

Answer 3

2 types:

-Central pontine myelinolisis:
Ponds: central fibers, spare periphery.
Tectum
Sometimes corticospinal tract.

-Extrapontine M:
-Thalami, GB, hemisphere subcortica, caudate

MR:
Acute:
-T2/FLAIR hyper
DWI restricted diffusion (since this is cytotoxic oedema). Changes improve after a week.
Gad: only 20% of cases will enhance. Resolves too.
Subacute: may resolve. Very uncommon to stay hyper (if yes, coagulative necrosis)
MRS: Acute: ↓ NAA, ↑ choline , ↑ Cho:Cr ratio