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Cerebellar peduncular myelinolysis in a patient receiving hemodialysis
Journal of the Neurological Sciences 253 (2007) 66 – 68 www.elsevier.com/locate/jns
Short communication
Cerebellar peduncular myelinolysis in a patient receiving hemodialysis J. Kim, T. Song, S. Park ⁎, I.S. Choi Department of Neurology, Yonsei University, College of Medicine, Seoul, Korea Received 11 May 2006; received in revised form 18 October 2006; accepted 19 October 2006 Available online 4 January 2007
Abstract Here, we report the observation of extrapontine lesions, in addition to the pontine lesions previously documented in a diagnosed case of hemodialysis-associated osmotic demyelination syndrome due to end-stage renal disease. The patient exhibited lesions on bilateral middle cerebellar peduncles, and had been receiving regular hemodialysis as treatment for end-stage renal disease. He presented with progressive gait disturbance and postural instability. Accompanying symptoms included peduncular hallucinations and mild cognitive dysfunction. Brain MRI revealed high signal intensity in the area of bilateral cerebellar peduncles on the diffusion and T2-weighted images, with a decreased signal intensity noted on the ADC map. The ataxic form of osmotic myelinolysis syndrome is quite rare. The involvement of the cerebellar peduncles in extrapontine myelinolysis in a patient with end stage renal disease has not, to our knowledge, been previously reported. Here, we describe the MRI findings and clinical features associated with this unique case, and include a review of the relevant literature. © 2006 Published by Elsevier B.V. Keywords: Extrapontine myelinolysis; Cerebellar peduncle; Hemodialysis; MRI
1. Introduction Osmotic demyelination syndrome is a well-known clinicopathological entity, which is characterized by edema and demyelination in the pons and extrapontine regions. Central pontine myelinolysis and extrapontine myelinolysis share radiological findings, clinical features, predisposing factors, and treatment options, although the etiology and pathogenesis of this disorder remain unclear [1]. In patients experiencing end-stage renal disease, osmotic demyelination syndrome may develop as a result of the renal disease itself, or due to osmotic changes induced during dialysis [2,3]. The characteristic lesions, even those in the extrapontine area, are most commonly located in the subcortical area, including the basal ganglia and the deep periventricular white matter [4].
⁎ Corresponding author. Department of Neurology, Yonsei University College of Medicine, 134 Sinchon-dong, Seodaemun-gu, Seoul, 120-752 Republic of Korea. Tel.: +82 2 2228 1606; fax: +82 2 393 0705. E-mail address: [email protected] (S. Park). 0022-510X/$ - see front matter © 2006 Published by Elsevier B.V. doi:10.1016/j.jns.2006.10.012
As far as the authors of this study are aware, extrapontine myelinolysis of the cerebellar peduncle has been reported in only one case [5], in which the patient was an alcoholic. We encountered a case of extrapontine myelinolysis in a patient who had received regular hemodialysis as treatment for endstage renal disease. In this case, a brain MRI revealed lesions on the patient's bilateral middle cerebellar peduncles. 2. Case report A 66-year-old male presented with progressive gait disturbance, postural instability, and cognitive dysfunction, all of which had begun 1 month before admission. Three days before his hospital admission, the patient lost his ability to ambulate, and intermittently experienced complex visual hallucinations, accompanied by gestures suggesting conversations with his relatives. The patient had previously suffered from chronic hypertension and insulin-dependent diabetes mellitus. In addition, he had been receiving regular hemodialysis due to end-stage renal disease. These hemodialysis treatments were administered three times a week,
J. Kim et al. / Journal of the Neurological Sciences 253 (2007) 66–68
67
Fig. 1. Brain MRI findings of 66-year-old male on regular hemodialysis treatment showed increased signal intensity on bilateral cerebellar peduncles (A), left basal ganglia (B), and bilateral periventricular white matter (C) on diffusion-weighted image. T2-weighted image at axial plane (E). The follow-up MRI on the 11th hospital day, ADC map (D) showed decreased signal intensity on bilateral cerebellar peduncles which suggested cytotoxic edema.
and had begun 3 years prior to his admission. The patient's visual hallucinations were transient and he had recovered in a few days, but retained a decreased attention span with impaired ability to calculate. Dysarthria was also observed, with no concomitant motor weakness. The patient exhibited no tremors or dysdiadochokinesis. Pinprick and deep tendon reflexes were decreased below the knees, but the patient's reflexes were relatively well-preserved in the upper extremities. Position and vibration senses were also decreased in the lower extremities. Tandem gait was impossible due to severe positional imbalance, and the patient was not able to maintain a standing position with his eyes open. BUN and creatinine levels were 46.4 and 8.0 mg/dl, respectively, evidencing no definite interval change compared to the values measured 1 month before. The patient's serum sodium and osmolarity were 138 mq/dl and 309.7 mOsmol/kg respectively, and had been 128 mq/dl and 289.7/mOsmol/kg at the onset of symptoms. ESR was 52 mm/hr. The brain MRI revealed significantly high signal intensity in bilateral middle cerebellar peduncles, the left basal ganglia, and bilateral periventricular deep white matter on the diffusion (Fig. 1A–C) and T2-weighted images (Fig. 1D), and T1weighted image showed decreased signal intensity without enhancement. The follow-up MRI, which was performed on the 11th hospital day, evidenced no clear interval change, and the ADC map showed decreased signal intensity in the aforementioned lesions (Fig. 1E). One month after discharge, no prominent clinical improvements were noted.
Self-ambulation was not possible during the 14 months of follow-up, until death due to sepsis. 3. Discussion Osmotic demyelination syndrome has become more easily diagnosed, since the discovery that the syndrome also affects the extrapontine sites. 10 to 50% of patients with pontine myelinolysis also exhibit extrapontine lesions [4,6,7]. Extrapontine lesions are generally found in the midbrain, thalamus, basal nuclei, deep periventricular white matter and cerebellum. Chronic alcoholism remains the most common underlying condition in central pontine myelinolysis, but this syndrome is most often observed after a rapid correction of chronic hyponatremia. In addition, other diseases which cause fluid and electrolyte disturbances may also lead to myelinolysis. The hypertonic fluid responsible for the characteristic edema remains in the extracellular space until endothelial integrity is restored. Moreover, this fluid may exert significant toxic effects on the myelin and oligodendrocytes. Therefore, vasogenic edema and leakage of the myelinotoxic substances leads to demyelination and axonal destruction [8]. Most patients with end-stage renal disease are also prone to rapid osmotic fluctuations, resulting from rapid changes in plasma solute levels after hemodialysis. The patient's metabolic status, in this case, indicated mild hyponatremia, elevated serum osmolarity, and an elevated BUN/Cr level due to renal failure, which was complicated by
68
J. Kim et al. / Journal of the Neurological Sciences 253 (2007) 66–68
the hemodialysis. All of these factors culminated in osmotic demyelination syndrome, although no abrupt changes or prominent fluctuations were evident during the progression of the disease. Bilateral middle cerebellar peduncular lesions were clinically relevant to the progressive gait disturbances and the prominent instability. The central pontine area was, however, clearly spared, although small lesions were observed in the basal ganglia and periventricular deep white matter. Seven cases of the ataxic form of central pontine myelinolysis have recently been reported [9], all of which (except for one) involved alcoholic patients, and the symptomatology of these cases also involved hyponatremia. In these reported cases, MRI revealed the extension of lesions toward the cerebellar peduncles, in addition to the characteristic pontine lesions. Only one case of cerebellar peduncular myelinolysis without the involvement of central pontine area has been reported [6], and here, also, the patient was an alcoholic. Our case differs in that the underlying cause of the myelinolysis was a complication of hemodialysis as a treatment for end-stage renal failure. The cognitive dysfunction in our patient indicated a mild dementic process due to his chronic consumptive status. Interestingly, the complex hallucinations exhibited by this patient, displayed transiently at admission, suggested the possibility of peduncular hallucination [10] secondary to brain stem compression as a result of edema of the bilateral cerebellar peduncles. The lack of anatomically relevant lesions to explain the patient's vivid and complex hallucinations increased this suspicion, although the radiological findings associated with osmotic demyelination syndrome do not always match the neurological signs. The high signal intensity in T2-weighted image, and the decreased signal intensity on T1-weighted image, without enhancement of the relevant lesions on the brain MRI, are consistent with the established features of pontine myelinolysis. These lesions, in patients with end-stage renal disease after hemodialysis, were reported to be different from other causes of osmotic demyelination syndrome, in that most of these lesions were rapidly reversible; this indicated that the lesions represented edema rather than actual myelinolysis [3,11]. The cerebellar peduncular regions, in this case, were clearly demarcated on the short term follow-up MRI, and the decreased signal intensity observed in the ADC map suggested cytotoxic edema; this has been reported in other cases [12]. The clinical outcome is known to be independent
of the severity of the clinical findings or the persistence of the lesion [13]. In contrast to the cases mentioned above, clinical improvement was not achieved during the 14 months of follow-up, until death due to sepsis. Patient refused follow-up image study due to economic problem in addition to frustration. This study describes a case of extrapontine myelinolysis involving mainly bilateral middle cerebellar peduncles, together with other extrapontine sites in a patient with endstage renal disease who was on regular hemodialysis treatment. This case was quite rare, owing to the unusual location of the myelinolysis in this patient group. References [1] Lampl C, Yazdi K. Central pontine myelinolysis. Eur Neurol 2002;47:3–10. [2] Endo Y, Oda M, Hara M. Central pontine myelinolysis: a study of 37 cases in 1000 consecutive autopsies. Acta Neuropathol 1981;53:145–53. [3] Agildere AM, Benli S, Erten Y, Coskun M, Boy-vat F, Ozdemir N. Osmotic demyelination syndrome with dysequilibrum syndrome: reversible MRI findings. Neuroradiology 1998;40:228–32. [4] Wright DG, Laureno R, Victor M. Pontine and extrapontine myelinolysis. Brain 1979;102:361–85. [5] Mangat KS, Sherlala K. Cerebellar peduncle myelinolysis: case report. Neuroradiology 2002;44:768–9. [6] Gocht A, Colmant HJ. Central pontine and extrapontine myelinolysis: a case of 58 cases. Clin Neuropathol 1987;6:262–70. [7] Kleinschmidt-Deasters BK, Rojiani A, Filley C. Central and extrapontine myelinolyis; then… and now. J Neuropathol Exp Eurol 2006;65:1–11. [8] Norenberg MD. A hypothesis of osmotic endothelial injury: a pathogenetic mechanism in central pontine myelinolysis. Arch Neurol 1983;40:66–9. [9] Garzon T, Mellibovsky L, Roquer J, Perich X, Diez-Perez A. Ataxic form of central pontine myelinolysis. Lancet Neurol 2002;1:517–8. [10] Nadvi SS, Ramdial PK. Transient peduncular hallucinations secondary to brain stem compression by a cerebellar pilocytic astrocytoma. Br J Neurosurg Dec 12 1998(6):579–81. [11] Tarhan NC, Agildere AM, Benli US, Ozdemir FN, Aytekin C, Can U. Osmotic demyelination syndrome in end-stage renal disease after recent hemodialysis: MRI of the brain. AJR 2004;182:809–16. [12] Chu K, Kang D-W, Ko S-B, Kim M. Diffusion-weighted MR findings of central pontine and extrapontine myelinolysis. Acta Neurol Scand 2001;104:385–8. [13] Menger H, Jorg J. Outcome of central pontine and extrapontine myelinolysis (n = 44). J Neurol 1999;246:700–5.
Short communication
Cerebellar peduncular myelinolysis in a patient receiving hemodialysis J. Kim, T. Song, S. Park ⁎, I.S. Choi Department of Neurology, Yonsei University, College of Medicine, Seoul, Korea Received 11 May 2006; received in revised form 18 October 2006; accepted 19 October 2006 Available online 4 January 2007
Abstract Here, we report the observation of extrapontine lesions, in addition to the pontine lesions previously documented in a diagnosed case of hemodialysis-associated osmotic demyelination syndrome due to end-stage renal disease. The patient exhibited lesions on bilateral middle cerebellar peduncles, and had been receiving regular hemodialysis as treatment for end-stage renal disease. He presented with progressive gait disturbance and postural instability. Accompanying symptoms included peduncular hallucinations and mild cognitive dysfunction. Brain MRI revealed high signal intensity in the area of bilateral cerebellar peduncles on the diffusion and T2-weighted images, with a decreased signal intensity noted on the ADC map. The ataxic form of osmotic myelinolysis syndrome is quite rare. The involvement of the cerebellar peduncles in extrapontine myelinolysis in a patient with end stage renal disease has not, to our knowledge, been previously reported. Here, we describe the MRI findings and clinical features associated with this unique case, and include a review of the relevant literature. © 2006 Published by Elsevier B.V. Keywords: Extrapontine myelinolysis; Cerebellar peduncle; Hemodialysis; MRI
1. Introduction Osmotic demyelination syndrome is a well-known clinicopathological entity, which is characterized by edema and demyelination in the pons and extrapontine regions. Central pontine myelinolysis and extrapontine myelinolysis share radiological findings, clinical features, predisposing factors, and treatment options, although the etiology and pathogenesis of this disorder remain unclear [1]. In patients experiencing end-stage renal disease, osmotic demyelination syndrome may develop as a result of the renal disease itself, or due to osmotic changes induced during dialysis [2,3]. The characteristic lesions, even those in the extrapontine area, are most commonly located in the subcortical area, including the basal ganglia and the deep periventricular white matter [4].
⁎ Corresponding author. Department of Neurology, Yonsei University College of Medicine, 134 Sinchon-dong, Seodaemun-gu, Seoul, 120-752 Republic of Korea. Tel.: +82 2 2228 1606; fax: +82 2 393 0705. E-mail address: [email protected] (S. Park). 0022-510X/$ - see front matter © 2006 Published by Elsevier B.V. doi:10.1016/j.jns.2006.10.012
As far as the authors of this study are aware, extrapontine myelinolysis of the cerebellar peduncle has been reported in only one case [5], in which the patient was an alcoholic. We encountered a case of extrapontine myelinolysis in a patient who had received regular hemodialysis as treatment for endstage renal disease. In this case, a brain MRI revealed lesions on the patient's bilateral middle cerebellar peduncles. 2. Case report A 66-year-old male presented with progressive gait disturbance, postural instability, and cognitive dysfunction, all of which had begun 1 month before admission. Three days before his hospital admission, the patient lost his ability to ambulate, and intermittently experienced complex visual hallucinations, accompanied by gestures suggesting conversations with his relatives. The patient had previously suffered from chronic hypertension and insulin-dependent diabetes mellitus. In addition, he had been receiving regular hemodialysis due to end-stage renal disease. These hemodialysis treatments were administered three times a week,
J. Kim et al. / Journal of the Neurological Sciences 253 (2007) 66–68
67
Fig. 1. Brain MRI findings of 66-year-old male on regular hemodialysis treatment showed increased signal intensity on bilateral cerebellar peduncles (A), left basal ganglia (B), and bilateral periventricular white matter (C) on diffusion-weighted image. T2-weighted image at axial plane (E). The follow-up MRI on the 11th hospital day, ADC map (D) showed decreased signal intensity on bilateral cerebellar peduncles which suggested cytotoxic edema.
and had begun 3 years prior to his admission. The patient's visual hallucinations were transient and he had recovered in a few days, but retained a decreased attention span with impaired ability to calculate. Dysarthria was also observed, with no concomitant motor weakness. The patient exhibited no tremors or dysdiadochokinesis. Pinprick and deep tendon reflexes were decreased below the knees, but the patient's reflexes were relatively well-preserved in the upper extremities. Position and vibration senses were also decreased in the lower extremities. Tandem gait was impossible due to severe positional imbalance, and the patient was not able to maintain a standing position with his eyes open. BUN and creatinine levels were 46.4 and 8.0 mg/dl, respectively, evidencing no definite interval change compared to the values measured 1 month before. The patient's serum sodium and osmolarity were 138 mq/dl and 309.7 mOsmol/kg respectively, and had been 128 mq/dl and 289.7/mOsmol/kg at the onset of symptoms. ESR was 52 mm/hr. The brain MRI revealed significantly high signal intensity in bilateral middle cerebellar peduncles, the left basal ganglia, and bilateral periventricular deep white matter on the diffusion (Fig. 1A–C) and T2-weighted images (Fig. 1D), and T1weighted image showed decreased signal intensity without enhancement. The follow-up MRI, which was performed on the 11th hospital day, evidenced no clear interval change, and the ADC map showed decreased signal intensity in the aforementioned lesions (Fig. 1E). One month after discharge, no prominent clinical improvements were noted.
Self-ambulation was not possible during the 14 months of follow-up, until death due to sepsis. 3. Discussion Osmotic demyelination syndrome has become more easily diagnosed, since the discovery that the syndrome also affects the extrapontine sites. 10 to 50% of patients with pontine myelinolysis also exhibit extrapontine lesions [4,6,7]. Extrapontine lesions are generally found in the midbrain, thalamus, basal nuclei, deep periventricular white matter and cerebellum. Chronic alcoholism remains the most common underlying condition in central pontine myelinolysis, but this syndrome is most often observed after a rapid correction of chronic hyponatremia. In addition, other diseases which cause fluid and electrolyte disturbances may also lead to myelinolysis. The hypertonic fluid responsible for the characteristic edema remains in the extracellular space until endothelial integrity is restored. Moreover, this fluid may exert significant toxic effects on the myelin and oligodendrocytes. Therefore, vasogenic edema and leakage of the myelinotoxic substances leads to demyelination and axonal destruction [8]. Most patients with end-stage renal disease are also prone to rapid osmotic fluctuations, resulting from rapid changes in plasma solute levels after hemodialysis. The patient's metabolic status, in this case, indicated mild hyponatremia, elevated serum osmolarity, and an elevated BUN/Cr level due to renal failure, which was complicated by
68
J. Kim et al. / Journal of the Neurological Sciences 253 (2007) 66–68
the hemodialysis. All of these factors culminated in osmotic demyelination syndrome, although no abrupt changes or prominent fluctuations were evident during the progression of the disease. Bilateral middle cerebellar peduncular lesions were clinically relevant to the progressive gait disturbances and the prominent instability. The central pontine area was, however, clearly spared, although small lesions were observed in the basal ganglia and periventricular deep white matter. Seven cases of the ataxic form of central pontine myelinolysis have recently been reported [9], all of which (except for one) involved alcoholic patients, and the symptomatology of these cases also involved hyponatremia. In these reported cases, MRI revealed the extension of lesions toward the cerebellar peduncles, in addition to the characteristic pontine lesions. Only one case of cerebellar peduncular myelinolysis without the involvement of central pontine area has been reported [6], and here, also, the patient was an alcoholic. Our case differs in that the underlying cause of the myelinolysis was a complication of hemodialysis as a treatment for end-stage renal failure. The cognitive dysfunction in our patient indicated a mild dementic process due to his chronic consumptive status. Interestingly, the complex hallucinations exhibited by this patient, displayed transiently at admission, suggested the possibility of peduncular hallucination [10] secondary to brain stem compression as a result of edema of the bilateral cerebellar peduncles. The lack of anatomically relevant lesions to explain the patient's vivid and complex hallucinations increased this suspicion, although the radiological findings associated with osmotic demyelination syndrome do not always match the neurological signs. The high signal intensity in T2-weighted image, and the decreased signal intensity on T1-weighted image, without enhancement of the relevant lesions on the brain MRI, are consistent with the established features of pontine myelinolysis. These lesions, in patients with end-stage renal disease after hemodialysis, were reported to be different from other causes of osmotic demyelination syndrome, in that most of these lesions were rapidly reversible; this indicated that the lesions represented edema rather than actual myelinolysis [3,11]. The cerebellar peduncular regions, in this case, were clearly demarcated on the short term follow-up MRI, and the decreased signal intensity observed in the ADC map suggested cytotoxic edema; this has been reported in other cases [12]. The clinical outcome is known to be independent
of the severity of the clinical findings or the persistence of the lesion [13]. In contrast to the cases mentioned above, clinical improvement was not achieved during the 14 months of follow-up, until death due to sepsis. Patient refused follow-up image study due to economic problem in addition to frustration. This study describes a case of extrapontine myelinolysis involving mainly bilateral middle cerebellar peduncles, together with other extrapontine sites in a patient with endstage renal disease who was on regular hemodialysis treatment. This case was quite rare, owing to the unusual location of the myelinolysis in this patient group. References [1] Lampl C, Yazdi K. Central pontine myelinolysis. Eur Neurol 2002;47:3–10. [2] Endo Y, Oda M, Hara M. Central pontine myelinolysis: a study of 37 cases in 1000 consecutive autopsies. Acta Neuropathol 1981;53:145–53. [3] Agildere AM, Benli S, Erten Y, Coskun M, Boy-vat F, Ozdemir N. Osmotic demyelination syndrome with dysequilibrum syndrome: reversible MRI findings. Neuroradiology 1998;40:228–32. [4] Wright DG, Laureno R, Victor M. Pontine and extrapontine myelinolysis. Brain 1979;102:361–85. [5] Mangat KS, Sherlala K. Cerebellar peduncle myelinolysis: case report. Neuroradiology 2002;44:768–9. [6] Gocht A, Colmant HJ. Central pontine and extrapontine myelinolysis: a case of 58 cases. Clin Neuropathol 1987;6:262–70. [7] Kleinschmidt-Deasters BK, Rojiani A, Filley C. Central and extrapontine myelinolyis; then… and now. J Neuropathol Exp Eurol 2006;65:1–11. [8] Norenberg MD. A hypothesis of osmotic endothelial injury: a pathogenetic mechanism in central pontine myelinolysis. Arch Neurol 1983;40:66–9. [9] Garzon T, Mellibovsky L, Roquer J, Perich X, Diez-Perez A. Ataxic form of central pontine myelinolysis. Lancet Neurol 2002;1:517–8. [10] Nadvi SS, Ramdial PK. Transient peduncular hallucinations secondary to brain stem compression by a cerebellar pilocytic astrocytoma. Br J Neurosurg Dec 12 1998(6):579–81. [11] Tarhan NC, Agildere AM, Benli US, Ozdemir FN, Aytekin C, Can U. Osmotic demyelination syndrome in end-stage renal disease after recent hemodialysis: MRI of the brain. AJR 2004;182:809–16. [12] Chu K, Kang D-W, Ko S-B, Kim M. Diffusion-weighted MR findings of central pontine and extrapontine myelinolysis. Acta Neurol Scand 2001;104:385–8. [13] Menger H, Jorg J. Outcome of central pontine and extrapontine myelinolysis (n = 44). J Neurol 1999;246:700–5.