Central Pontine myelinolysis syndrome in a patient with chronic alcohol abuse

F. Labrianou1, G. Ntetskas 1, V. Papastergiou 2, M. Stampori 2, E. Anastasiou 2, K. Roufas 1, E. Asonitis 2, F.

Alourda 3, I. Karagiorgi 1, A. Kotis 4, S. Karatapanis 2

1 Nephrology Department, 2 1st Pathology Clinic, 3Neurology Department, 4CT and MRI Department

General Hospital of Rhodes

Introduction

Central pontine myelinolysis syndrome is an acutre non-inflammatory 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 ReportA 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.

MRI findings

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

Discussion

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 T1-weighted 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.

Conclusion

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

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