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Central pontine myelinolysis in a 6-month-old infant with rapidly corrected hyponatremia.

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LETTERS
Central Pontine
. . .
Myelinolysis in a
6-Month-Old Infant
with Rapidly Corrected
Hyponatremia
David J. Chercover, MD, and Margaret G. Norman, MD
A 4-month-old boy was treated by a Roux-en-Y hepatojejunostomy with exteriorization of a loop of bowel (Kasai I1
procedure) for extrahepatic biliary atresia. Over the fourth
and fifth postoperative days the infant lost large amounts of
fluid from the loop of bowel. On the fifth postoperative day
the serum sodium level dropped to 115 mEq/L, and the infant received 60 ml of 3% saline solution in one hour. By six
hours after the initial serum sodium measurement, the value
had risen to 124 mEq/L. O n the sixth day the serum sodium
level fluctuated from 122 mEq/L to 128 mEq/L over four
hours, with a further rise to 130 mEq/L over the next three
hours. No neurological examination was recorded on the
chart during this period. On the forty-third postoperative day
the chart indicated that the patient was drowsy and falling
Section of pons stained with luxol fast blue. Note central area of
myelin loss, with sharp lateral borders in rni&le cerebellar peduncles and persistence of myelin in corticospinal tracts. ( x 7 )
asleep during examination. Cranial nerves two to twelve were
noted to be normal. Reflexes were 2 + . Plantar reflexes were
downgoing. The next day the child’s eyes opened spontaneously but they did not follow an object, and the child moved
all extremities when touched. The child died the next day.
Postmortem examination showed biliary cirrhosis with
splenomegaly and ascites. Gross examination of the brain
showed an indistinct, ill-defined gray area in the central pons.
A focal symmetrical area of demyelination was found in the
basis pontis (Figure). The chief loss of myelin was from the
pontocerebellar fibers, although the medial portions of
the corticospinal and corticopontine tracts were also demyelinated. In the center of the lesion there were neuronal loss
and focal collections of neuroaxonal swellings. Around this
central area the tissue was spongy, with neurons persisting,
although myelin was lost. Microglia and hypertrophied astrocytes were present in moderate numbers; only a few foamy
macrophages were present. N o stainable myelin remained in
the lesion or in the macrophages. The lesion was considered
on morphological grounds to be several weeks old.
Originally described in 1959 in elderly male alcoholics,
central pontine myelinolysis has since been described in a
variety of other diseases. In children it has been seen with
craniopharyngioma and as a sequela of mumps, volvulus, Wilson’s disease, pineal germinoma, acute leukemia, Hodgkin’s
disease, chronic liver and kidney disease, sickle-cell disease,
idiopathic obesity, generalized muscular disease, and pyramidal tract disease. Dehydration and electrolyte imbalance
were present in many of these cases [I, 4-61. Until now, the
youngest reported patient was 1 year old [ 11. Because there
is a low level of suspicion for central pontine myelinolysis in
261
childhood despite reported cases, we are, to our knowledge,
reporting the youngest affected patient.
Central pontine myelinolysis is attributed to overly rapid
correction of hyponatremia, as occurred in this patient, although the precise mechanism is not known 12, 31. In two
experimental models, central pontine myelinolysis has been
produced in rats and dogs by rapid correction of hyponatremia f2, 3).
The authors thank Dr G. Baumgard for permission to publish this
case report.
Activity of Pyruvute Carboxylase in Fibroblasts
Group
Controls (n = 11)
Mean ? S D
Range
Patients
1
2
3
Department of Pathology
B. C , Childvent Hospital and University
of British Columbia
4480 Oak St
Vancouver, BC, Canada V6H 3V4
References
1. Cadman TE, Rorke LB: Central pontine myelinolysis in childhood and adolescence. Arch Dis Child 44:342-350, 1969
2. Lauren0 R Central pontine myelinolysis following rapid correction of hyponatremia. Ann Neurol 13:232-242, 1983
3. Norenberg MD, Leslie KO, Robertson AS: Association between
rise in serum sodium and central pontine myelinolysis. Ann
Neurol 11:128-135, 1982
4. Rosman NP, Kakulas BA, Richardson EP Jr: Central pontine
myelinolysis in a child with leukemia. Arch Neurol 14:273-280,
1966
5. Ule G, Jacob H: Chronische infantile zentrale pontine Myelinolyse vom multifokalen Typ mit sekundiren Capillarcalcinosen
and Hypoxieschaden. Acta Neuropathol 452:43-48, 1978
6. Valsalmis MP, Peress NS, Wright LD: Central pontine myelinolysis in childhood. Arch Neurol 25:307-312, 1971
Pyruvate Carboxylase
Activity Is Not Abnormal
in Fibroblasts of Patients
with Friedreich’s Ataxia
U. J. Dijkstra, MD, J. M. F. Trijbels, PhD,
W. Ruitenbeek, PhD, J. A. J. M. Bakkeren, PhD,
A. J. M. Janssen, F. J. M. Gabreels, MD, PhD,
and E. M. G. Joosten, MD, PhD
Recently [I], we described a group of patients with Friedreich‘s ataxia in whom pyruvate carboxylase (PC) activity was
decreased not only in liver tissue, but also in fibroblasts. The
latter conclusion now appears to be an error. The activities in
patients’ fibroblasts were compared with those in 6 control
cell lines having a mean activity of 252 ? 68 nmol/hr/mg
protein. After the study was finished, PC activity was measured in some other fibroblast lines from controls using the
same method. These cells showed activities three to four
times lower than our reported values {I) (Table). This change
262 Annals of Neurology Vol 16 No 2 August 1984
Pyruvate Carboxylase Activity
(nmol/hr/mg protein)
79
? 25
43-122
68
67
49
39
66
61
83
in control range could not be ascribed to variation in the
number of passages a n d o r in the time of harvesting during
the culture cycle. Although the PC activity slightly decreased
with the number of passages, this could not have interfered
with our results, as the cells from both of our control groups
had gone through approximately the same number of passages. W e found no influence of the number of days of subculturing on the PC activity. Raghunathan and associates [ 31,
after accurately monitoring the PC activity in fibroblasts during the culture cycle, reported one cell line having an activity
four times higher than that of other lines. Those authors
suggested the existence of three groups of fibroblast lines
classified according to PC specific activity, perhaps because of
genetic polymorphism.
It may be that this phenomenon has played a role in the
fixation of the ranges of our controls. The PC activity in 11
control fibroblast lines was recently found to be 79 t 25
nmouhdmg protein (mean % SD), range 43 to 122. This
figure agrees well with control values reported by various
other groups 12). It was remarkable that during this period of
measurements one cell line with an extreme activity (300
nmol/hr/mg protein) was again found.
We also studied the PC activity in fibroblasts of the three
patients not examined in our earlier report El]. The values
found were in the same range as the activity found in the
patients already mentioned.
Institute of Neurology and
Institute of Pediatrics
Radboud University Hospital
P.O. Box 9101
6500 HB Nijnzegen, The Netherlands
References
1. Dijkstra UJ, WillemsJL, Joosten EMG, Gabreels FJM: Friedreich
ataxia and low pyruvate carboxylase activity in liver and
fibroblasts. Ann Neurol 13:325-327, 1983
2. Marsac C, Augereau C, Feldman G , et al: Prenatal diagnosis of
pyruvate carboxylase deficiency. Clin Chim Acta 119:121-127,
1982
3. Raghunathan R, Russell JD, Arinze IJ: Pyruvate carboxylase and
phosphoenolpyruvate carboxykinase in cultured human fibroblasts. J Cell Physiol 92:285-292, 1977
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infant, central, months, hyponatremia, corrected, pontine, myelinolysis, old, rapidly
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