Reversible central pontine and extrapontine myelinolysis in a 16-year-old girl

A rare case of an osmotic demyelination syndrome in a 16-year-old girl is presented. MRI in the acute stage revealed a focal abnormal signal within the basis pontis and both caudate nuclei and putamina. Two years later brain lesions had disappeared on T1- and T2-weighted imaging, indicating that central pontine and extrapontine myelinolysis may be completely reversible. Received: 4 July 2000     

Central pontine and extrapontine myelinolysis owing to disequilibrium syndrome

Neurologic disorders can be seen in patients with end-stage renal failure owing to complications of hemodialysis or peritoneal dialysis. The disequilibrium syndrome can be seen, usually soon after or toward the end of dialysis. We report a patient with central pontine and extrapontine myelinolysis owing to disequilibrium syndrome. The patient had depressed consciousness, agitation, tremor, stupor and hyperactive deep tendon reflexes toward the end of the second peritoneal dialysis. A brain computed tomographic (CT) scan showed hypodense lesions in pontine and extrapontine locations without radiocontrast medium enhancement After 2 days, the patient had only minimal memory deficits. A control brain CT scan 1 week later showed a decrease of the lesions in central pontine and extrapontine locations. Central pontine and extrapontine myelinolysis should be suspected and investigated in the acute neurologic disorders of dialysis patients.     

Extrapontine myelinolysis with involvement of the hippocampus in three children with severe hypernatremia

Central pontine myelinolysis is a disorder of unknown etiology linked to overly aggressive correction of hyponatremia. In addition to the typical location of demyelination with preservation of neurons and axon cylinders in the basis pontis, similar lesions have been described in extrapontine locations. Central pontine myelinolysis and extrapontine myelinolysis usually occur together, and are identified at autopsy rather than in life because symptoms of extrapontine myelinolysis are often masked in the critically ill patient. Central pontine myelinolysis is described in children, usually in the clinical setting of hyponatremic dehydration. Extrapontine myelinolysis has not been described in children previously. We report three children with severe hypernatremia and extrapontine myelinolysis involving various combinations of thalamus, basal ganglia, external and extreme capsules, and cerebellar vermis. All three had additional involvement of the hippocampus seen on T2-weighted magnetic resonance imaging. None of the three had detectable pontine lesions. Clinical features of the three cases were dehydration in a 28-month-old girl, respiratory syncytial virus bronchiolitis in a 14-month-old girl, and acute respiratory failure due to anaphylaxis after consumption of walnuts in a 3-year-old boy. Peak sodium values in each child were 195, 168, and 177 mmol/L, respectively; each received aggressive treatment for hypernatremia. We believe this to be the first report of extrapontine myelinolysis in children, the first report of extrapontine myelinolysis without central pontine myelinolysis in children, and the first report in children of hippocampal formation involvement. The pathogenesis of the central and extrapontine myelinolysis complex in children is more complicated than previously believed, and might differ significantly from that of adults.     

Parkinsonism after correction of hyponatremia with radiological central pontine myelinolysis and changes in the basal ganglia.

Parkinsonism has been rarely described following central pontine and extrapontine myelinolysis. We report a case of parkinsonism developing following rapid correction of hyponatremia with radiological evidence of central pontine myelinolysis and changes in the basal ganglia. A 56-year-old man developed drooling and bilateral hand tremors 3 weeks after correction of hyponatremia from 103 to 125 mmol/L over 14 h. He had a prominent 6 Hz resting tremor which worsened with action and mild cogwheel rigidity. Magnetic resonance imaging (MRI) showed changes consistent with central pontine myelinolysis and increased signal on T1-weighted images in the putamen bilaterally. His tremor responded well to L-dopa therapy. There have been several other cases of parkinsonism developing after central pontine/extrapontine myelinolysis. Increased signal in the basal ganglia on T1-weighted images has been described in another case of central pontine myelinolysis imaged about the same time after sodium correction as our case.     

A case report of central pontine and extrapontine myelinolysis which occurred during pregnancy and was accompanied by choreic movement

A 25-year-old female in the 17th week of pregnancy was diagnosed by MRI as having central pontine and extrapontine myelinolysis. Serial observations with MR showed gradual disappearance of the lesions in the pons and striatum. Improvement of the symptoms took place shortly before disappearance of the lesions on MRI pictures. The initial symptoms were consciousness disturbance, cranial nerve palsy and tetraparesis. Before the latter disappeared seven months after occurrence of the disease, all other symptoms gradually improved. They were followed by delayed appearance of choreic movements, which was still remaining one year after discharge. It is rare for a pregnant woman to be attacked by central pontine myelinolysis. Moreover, very few symptoms caused by such extrapontine lesions have so far been reported. Also, a review of the relevant literature by the authors found no other case showing choreic movements. This report is of an extremely rare case of central pontine and extrapontine myelinolysis which occurred during pregnancy and is accompanied by choreic movements.     

Pontine myelinolysis and delayed encephalopathy following the rapid correction of acute hyponatremia

We describe a case of pontine myelinolysis associated with hyponatremia and hyperammonemia resulting from bladder irrigation during a transurethral prostatic resection. Following the procedure the patient exhibited seizurelike activity. He underwent rapid correction of the hyponatremia, he initially recovered but developed encephalopathy 19 days later. Magnetic resonance images showed symmetrical lesions in the white matter of the cerebellar peduncles. A relatively small pontine lesion was also noted. The patient later recovered. This case demonstrates that myelinolysis associated with rapid correction of hyponatremia may be greater in the cerebellar peduncles than in the central pons.     

Osmotic myelinolysis in a normonatremic patient

Osmotic demyelination syndrome is usually associated with hyponatremia or rapid correction of this condition. The prognosis is usually fatal. We treated a 34-year-old chronic renal failure patient who did not have hyponatremia but developed severe pontine myelinolysis demonstrated with MRI. Serial MRI revealed gradual reduction of the lesions over 2 months. This case demonstrates that osmotic demyelination syndrome is not always associated with hyponatremia, and that, although the prognosis is usually poor, some patients recover.     

Intrafamilial variability in fragile X-associated tremor/ataxia syndrome.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a progressive adult-onset tremor/ataxia syndrome caused by premutations in the FMR1 gene. In cranial MRI, the most characteristic findings are bilateral T2 hyperintense lesions within the middle cerebellar peduncles. Here we present a sibpair of two affected brothers presenting with very different symptoms (typical FXTAS versus essential tremor-like), disease progression, and MRI findings, illustrating broad intrafamilial variability of FXTAS. Also, their family history suggests further evidence of possible manifestation of FXTAS in women.     

Central pontine and extrapontine myelinolysis: a report of 58 cases

In 58 cases with central pontine myelinolysis (CPM) and/or extrapontine myelinolysis, systematic examination of the central nervous system was performed. The demyelinating disease occurred in three subtypes: (1) CPM, in which the lesion was confined to the pons, (2) CPM combined with extrapontine myelinolysis and (3) exclusively extrapontine myelinolysis. Type (1) was found in 27 cases, (2) in 18 cases and (3) in 13 cases. Cerebellum and lateral geniculate body were the most frequently affected extrapontine regions. One case with an extreme extension of the lesions is described in detail. Extrapontine lesions seem to be more frequent and widespread than has been hitherto reported in the literature.     

A case of chronic methyl bromide intoxication showing symmetrical lesions in the basal ganglia and brain stem on magnetic resonance imaging]

A 30-year-old man developed paresthesia in the feet, unstable gait and blepharoptosis subsequent to pharyngeal pain while working in a warehouse of imported fruit and vegetable fumigated with methyl bromide and cyanate. Neurological examination showed bilateral blepharoptosis, diplopia, ataxic gait and paresthesia below the inguinal region. The serum concentration of thiociane, a metabolite of cyanide, was within normal limits, but that of bromide was elevated (43.7 mg/l, normal: 3.7-8.6). Thus we diagnosed the patient as intoxication of methyl bromide. Magnetic resonance imaging of the brain (MRI) revealed bilateral symmetrical lesions of high signal intensity in the posterior region of the putamen, the subthalamic nuclei, the dorsal medulla oblongata corresponding to inferior cerebellar peduncles and vestibular nuclei, the inferior colliculi and the periaqueductal gray matter surrounding the oculomotor nucleus of the midbrain. As far as we know, this is the first report of MRI detected cerebral lesions in a case with intoxication of methyl bromide.     

脑桥中央和脑桥外髓鞘溶解症的临床分析和影像特点

目的:探讨脑桥中央和脑桥外髓鞘溶解症的临床及神经影像特点。方法:分析3例脑桥中央髓鞘溶解症和1例脑桥外髓鞘溶解症患者的临床特点,包括起病前诱因、临床表现、头颅MRI特点、治疗及预后情况。结果:4例患者均有慢性形成低钠血症后被快速纠正的病史,以意识改变、构音和吞咽困难、四肢瘫痪等为临床表现。3例脑桥中央髓鞘溶解症的MRI表现为脑桥部位对称性的T1加权低信号灶、T2加权高信号灶,呈环状分布;1例脑桥外髓鞘溶解症者在基底节区域有对称性的T1加权低信号、T2加权高信号病灶。4例患者总体预后良好。结论:提高髓鞘溶解症的认识对于本病的防治非常重要,缓慢纠正慢性形成的低钠血症是预防的关键。     

A case showing Wallerian degeneration of the bilateral middle cerebellar peduncles on MRI followed by the right pontine infarction]

We report a 63-year-old man who presented with the left facial palsy, the left hemiparesis, the left limb ataxia, and the bilateral truncal ataxia. On admission, magnetic resonance imaging (MRI) showed an abnormal high intensity lesion at the right paramedian region of the upper to middle pons on T2-weighted images (T2WI). He was diagnosed as having a pontine lacunar infarction. The contralateral cerebellar lesions were caused by involvement of the pontocerebellar fibers. On the 29th day from the onset, MRI showed the new abnormal high intensity lesions at the bilateral middle cerebellar peduncles on T2WI. These lesions were supposed to be Wallerian degeneration caused by involvement of the pontocerebellar fibers. This case suggests that Wallerian degeneration occurs followed by a unilateral infarction involving pontocerebellar fibers.     

"Man-in-the-barrel" syndrome as delayed manifestation of extrapontine and central pontine myelinolysis: beneficial effect of intravenous immunoglobulin

"Man-in-the-barrel" syndrome has been rarely described following osmotic myelinolysis. We report a case of a 45-year-old woman admitted with septicemia and severe hyponatremia. She presented with a "man-in-the-barrel" syndrome which developed more than 10 days after rapid correction of the hyponatremia. There was radiological evidence of central pontine and extrapontine myelinolysis. Three days after completing a course of intravenous immunoglobulin therapy (0.4 g/kg body weight/day for 5 days) there was considerable improvement (Expanded Disability Status Scale score improved 30%). This case, reported for its peculiar mode of development, unusual presentation and challenging therapeutic response to intravenous immunoglobulin, highlights the enigmatic and unpredictable aspects of osmotic myelinolysis.     

Osmotic demyelination syndromes: central and extrapontine myelinolysis.

Osmotic demyelination syndromes are often progressive disorders, with clinical features ranging from a mild tremor or dysarthria to a progressive quadraparesis. Although rapid correction of serum sodium is known to be a potent causative factor, additional pathogenic factors exist, which appear critical in predisposing pontine and extrapontine glia to osmotic stress. Interestingly, several cases of osmotic demyelination have emerged where serum sodium was found to be within normal limits and minimal or no correction of a hypo or hypernatraemic state was implemented. We describe two cases--one of extra pontine and another of central-pontine myelinolysis, both of which have occurred in the context of relatively normal serum sodium. The first case illustrates the association of extrapontine myelinolysis with the traditional risk factor of alcoholic cirrhosis and intravenous fluid resuscitation, while the second, more unusual case, describes a patient who developed central pontine myelinolysis possibly in association with alpha interferon therapy.     

Dystonia in central pontine myelinolysis without evidence of extrapontine myelinolysis.

A 44-year-old female is described who developed persistent upper extremity and orolingual dystonia several weeks after suspected onset of central pontine myelinolysis (CPM), later confirmed by characteristic pontine lesions on MRI. No foci of the extrapontine myelinolysis were evident. This case confirms that dystonia may be a late and persistent sequela of CPM and may occur in the absence of visible lesions outside the brainstem.     

Central pontine and extrapontine myelinolysis associated with acute hepatic dysfunction

Central pontine myelinolysis and extrapontine myelinolysis are rare demyelinating diseases of the central nervous system. These diseases are related frequently to rapid correction of hyponatremia. They have also been described in association with other underlying conditions such as alcoholism and malnutrition. In the present study, we report a case of central pontine and extrapontine myelinolysis with acute hepatic dysfunction. The patient had no apparent evidence of hyponatremia and no history of alcohol abuse. On admission, the patient was lethargic; dysphagia, dysarthria, and quadriplegia were noted. Laboratory examination showed significantly increased transaminase without hyponatremia. Magnetic resonance imaging revealed abnormal signal intensities in the pons and thalamus. Consciousness level and clinical symptoms improved gradually within a week. We suggest that acute hepatic dysfunction may play an important role in the development of central pontine myelinolysis and extrapontine myelinolysis.     

Central pontine and extrapontine myelinolysis: report of an autopsied case and review of the literature

An autopsied case of central pontine and extrapontine myelinolysis in a 16-year-old diabetic girl is described. Due to dehydration she was treated vigorously with daily intravenous isotonic saline, from the first day of hospitalization. In the first three days the serum sodium level increased by more than 30 mEq/l when compared with the initial level. By the next days the serum sodium level, after a mild drop, rose again and was maintained above normal range for a further 12 days. On the sixth day of this new and sustained serum sodium increase, the patient presented progressive neurological manifestations that remained until her death, characterized by mutism, inability to eat, to move her head, trunk, and members and, in addition, retention of respiratory secretions. The neuropathological examination showed massive central pontine myelinolysis and similar myelinolytic lesions in the subcortical white matter of the temporal lobe, the right optic tract, the external and extreme capsules to the right, the main mammillary tract and the subcortical white matter of the left cerebellar hemisphere. The review of the literature on central pontine and extrapontine myelinolysis shows that the present case is the 30th of such condition. The clinical picture and the etiopathogenesis of central pontine and extrapontine myelinolysis are commented upon. It is suggested, as possible causative factors, the persistent and rapid correction of serum sodium concentration as well as its fluctuation in patients with hyponatremia and/or dehydration.     

Central pontine myelinolysis, an update

Central pontine myelinolysis (CPM) can be regarded as one of the demyelinating syndromes. First described by Adams et al. in 1959 in their chronic alcoholic patients, it has now been described in the malnourished, the chronically debilitated, the renal, the hepatic and the transplant patient among others. Pathologically, it is defined as a symmetric area of myelin disruption in the center of the basis pontis, although similar symmetric lesions have also been described occurring with CPM as well as independently in other brain areas (extrapontine myelinolysis or EPM) including the cerebellar and neocortical white/gray junctional areas, thalamus and striatum. Possible mechanisms include a hyperosmotically induced demyelination process resulting from rapid intracellular/ extracellular to intravascular water shifts producing relative glial dehydration and myelin degradation and/or oligodendroglial apoptosis. The process most often occurs during rapid rebalancing of the electrolyte parameters in the hyponatremic patient. Avoidance of CPM/EPM is dependent upon recognizing those patients with conditions pre-disposing them to osmotic myelinolysis and then moderating the rate of normalization of the electrolyte imbalance. The morbidity and mortality of CPM/EPM has been greatly reduced by recognition of pre-disposing conditions, increased understanding of the pathophysiology, intensive treatment, and rapid diagnosis and monitoring with advanced neuroimaging.     

Fatal brain stem event complicating acute pancreatitis.

Acute pancreatitis, developing in a patient with chronic renal failure, was complicated by a fatal neurological illness during which MRI showed pontine and extrapontine changes consistent with pontine and extrapontine myelinolysis. At post mortem, acute pancreatitis was confirmed but the neuropathological findings were more in keeping with an unusual presentation of acute haemorrhagic leucoencephalitis, perhaps even representing a form of 'pancreatic encephalopathy'. Although the development of CT and MRI scanning has greatly increased the resolution of neuroimaging and facilitated diagnosis during life, the value of autopsy examination is confirmed in cases such as this. Sometimes the findings may raise more questions than may have been answered - this too is an important function!     

Bilateral ballism in a patient with diabetes mellitus and chronic renal failure

Acute movement disorder associated with bilateral basal ganglia lesions is an increasingly recognized syndrome in patients with end-stage renal disease, especially in the setting of diabetes mellitus. The exact mechanism of the basal ganglia lesions is unclear. We report a patient with end-stage diabetic nephropathy admitted to our clinic with acute onset bilateral ballistic movements.