F.
1
Labrianou , G.
K.
1
Ntetskas , V.
1
Roufas ,
2
Papastergiou ,
2
E. Asonitis ,
3
F. Alourda ,
2
M. Stampori ,
I.
2
S. Karatapanis
2
E. Anastasiou ,
1
Karagiorgi , A.
4
Kotis ,
1 Nephrology Department, 2 1st Pathology Clinic, 3Neurology Department,
4CT
and MRI Department
General Hospital of Rhodes
Central pontine myelinolysis syndrome is an acutre noninflammatory demyelinating disease of the central nervous system
affecting the pons, thalamus, subthalamic nucleus, geniculate body,
putamen, globus pallidum, white matter and cerebellum. [1]
The exact cause still remains uncertain. In the past rapid
correction of hyponatriemia has been considered a major factor as it
predisposes the brain to osmotic injury. [1-3] However, normonatriemic,
hypernatiemic and hypokaliemic patients with CPM have also been
reported. [4-6]
Other CPM associated risk factors include alcoholism,
malnutrition, liver disease, renal failure and use of diuretics. [7-10]
We present a case of CPM syndrome in a chronic alcohol abuser
with no electrolytic abnormalities.
Case Report
A 61-year old male patient with history of smoking, alcoholism,
hypertension and dyslipidemia was admitted to the General Hospital of
Rhodes due to dizziness, formication of left extremities and ingestion
difficulties. Physical examination was impeccable. Neurologic
examination revealed decreased sensitivity of the left extremities,
dysarthria, unsteadiness of gait and left nystagmus.
Laboratory investigations showed normal total blood count, slight
increase of SGOT (49 U/L) and γ-GT (94U/L). Serum sodium and
potassium levels were within normal range. Brain CT scan showed
brain atrophy, hypodense areas of the pons, medulla oblongata and
lateral ventricles. Cerebral MRI scan showed hyperdense areas on the
pons, the right posterior medulla oblongata and the lateral ventricles. On
the T2 sequence, hyperdense deformations in the white matter were
observed. These findings were compatible with diagnosis of central
pontine myelinolysis.
Therapy was conservative, with infusion of 0.9% normal saline
solution and observation.
The clinical condition of the patient ameliorated within 15 days
from the onset and by day 30 all symptoms disappeared.
Figures 1, 2. Hyperdense areas on the pontis
Figures 3, 4. Hyperdense deformations in the
white matter
Figures 5, 6. Hyperdense areas the lateral
ventricles
CPM was first described by Adams et al in 1959 in a
clinopathological study on alcoholic and malnourished patients. [7]
This syndrome is characterized by disturbance of
consciousness and can present a variety of clinical manifestations
ranging from mild tremor and dysarthria to locked-in syndrome, from
hemiparesis to quadriparesis and from slightly decreased level of
consciousness to coma. [11, 12]
Although rapid correction of electrolytic disorders, especially
hyponatriemia has for long been considered the main case of this
syndrome, recently an apoptotic hypothesis has been proposed. [8]
According to this hypothesis, a depletion of the energy supply to glial
cells can limit the function of Na+/K+ ATPase pumps, reducing their
adaptability to even minimal changes in serum sodium
concentrations, leading to apoptosis.
In our case, serum sodium levels were within normal range
but during his hospitalization varied from 136 to 140mmol/L and
infusion of 0.9% normal saline solution was limited to 1lt per day,
avoiding rapid correction of serum sodium levels. This hypothesis
may be able to explain the presence of CPM in our patient.
In the past diagnosis of CPM was confirmed only in autopsies.
With the introduction of modern imaging techniques, especially brain
MRI that has a greater sensitivity to demyalination and provides
clearer data on pontine lesions, diagnosis became much easier to
obtain. MRI findings in CPM include symmetric hypointensity on T1weighted images, hyperintensity on T2-weighted and FLAIR images,
commonly situated on the basis pontis and may extend from the
pontomedullary junction into the midbrain. [13, 14]
These findings are not specific of CPM and may be observed
in ischemia, multiple sclerosis or neoplasms. The characteristic that
allows differential diagnosis is the symmetry of the lesions in CPM,
that is absent in all the other conditions.
Our patient presented hyperdense areas on the pons, the right
posterior medulla oblongata, the lateral ventricles and the white
matter. (Table 1)
Treatment is conservative, with slow correction of electrolytic
abnormalities and continuous monitoring. Prognosis may range from
complete to partial recovery, from no improvement to death. In the
survivors, neurological symptoms may persist for months. In our
case, symptoms started regressing within 15 days from the onset
and disappeared by day 30.
CPM should be included in the differential diagnosis of neurocognitive impairment in patients with history of chronic alcoholism even in
absence of electrolytic abnormalities.
References
1. Brown WD. Osmotic demyelination disorders: central pontine and
extrapontine myelinolysis. Curr Opin Neurol 2000; 13: 691–7. [PubMed:
11148672]
2. Laureno R. Central pontine myelinolysis following rapid correction of
hyponatremia. Ann Neurol. 1983 Mar;13(3):232-42.
3. Sterns RH, Riggs JE, Schochet SS Jr. Osmotic demyelination syndrome
following correction of hyponatremia. N Engl J Med. 1986 Jun
12;314(24):1535-42.
4. Mast H, Gordon PH, Mohr JP, Tatemichi TK. Central pontine myelinolysis:
clinical syndrome with normal serum sodium. Eur J Med Res. 1995 Dec
18;1(3):168-70.
5. Bähr M, Sommer N, Petersen D, Wiethölter H, Dichgans J. Central
pontine myelinolysis associated with low potassium levels in alcoholism. J
Neurol. 1990 Jul;237(4):275-6.
6. Lohr JW. Osmotic demyelination syndrome following correction of
hyponatremia: association with hypokalemia. Am J Med. 1994 May;96(5):40813.
7. Adams RD, victor M, Mancall EL. Central pontine myelinolysis: a hitherto
undescribed disease occurring in alcoholic and malnourished patients. AMA
Arch Neurol Psychiatry. 1959 Feb;81(2):154-72.
8. Ashrafian H, Davey P. A review of the causes of central pontine
myelinosis: yet another apoptotic illness? Eur J Neurol. 2001 Mar;8(2):103-9.
9. Lampl C, Yazdi K. Central pontine myelinolysis. Eur Neurol. 2002;47(1):310.
10. Rippe DJ, Edwards MK, D'Amour PG, Holden RW, Roos KL. MR imaging
of central pontine myelinolysis. J Comput Assist Tomogr. 1987 JulAug;11(4):724-6.
11. Kleinschmidt-Demasters BK, Rojiani AM, Filley CM. Central and
extrapontine myelinolysis: then...and now. J Neuropathol Exp Neurol. 2006
Jan;65(1):1-11.
12. Martin RJ. Central pontine and extrapontine myelinolysis: the osmotic
demyelination syndromes. J Neurol Neurosurg Psychiatry. 2004 Sep;75 Suppl
3:iii22-8.
13. DeWitt LD, Buonanno FS, Kistler JP, Zeffiro T, DeLaPaz RL, Brady TJ, et
al. Central pontine myelinolysis: demonstration by nuclear magnetic
resonance. Neurology. 1984 May;34(5):570-6.
14. Ağildere AM, Benli S, Erten Y, Coşkun M, Boyvat F, Ozdemir N. Osmotic
demyelination syndrome with a dysequilibrium syndrome: reversible MRI
findings. Neuroradiology. 1998 Apr;40(4):228-32.