Download utility of optic coherence tomography (oct) in the

ORIGINAL ARTICLE
ARCH SOC ESP OFTALMOL 2006; 81: 383-390
UTILITY OF OPTIC COHERENCE TOMOGRAPHY (OCT)
IN THE FOLLOW-UP OF IDIOPATHIC INTRACRANIAL
HYPERTENSION IN CHILDHOOD
UTILIDAD DEL TOMÓGRAFO DE COHERENCIA ÓPTICA (OCT)
EN EL SEGUIMIENTO DE LA HIPERTENSIÓN INTRACRANEAL
IDIOPÁTICA EN LA INFANCIA
SÁNCHEZ-TOCINO H1, BRINGAS R2, IGLESIAS D1, GONZÁLEZ-PÉREZ A3,
DEL VILLAR-GALÁN R3
ABSTRACT
RESUMEN
Purpose: To show the utility of optic coherence
tomography (OCT) in the follow up of the idiopathic intracranial hypertension (IIH) in childhood.
Methods: Three girls, aged between 4 and 11
years, were diagnosed and subsequently followed
with the help of OCT for an episode of idiopathic
intracranial hypertension. All of them had presented with non-specific symptoms such as visual disturbance, headache, stomach ache, and in one case
diplopia and torticolis. Brain imaging studies were
normal, however lumbar puncture found an elevated intracranial pressure. Visual fields were tested
using Octopus automated perimetry and the optic
nerve fiber layer (ONF) was measured by OCT at
each of the attendances.
Results: The visual acuity was normal in all cases,
but two girls had evidence of an abducens nerve
palsy. Fundus biomicroscopy revealed marked
papilledema. The thickness of the ONF was increased 2-3 times over normally expected levels. The
Objetivo: Mostrar la utilidad de la tomografía de
coherencia óptica (OCT) en el seguimiento de la
hipertensión intracraneal idiopática (HII) en la edad
pediátrica.
Métodos: Se ha realizado el diagnóstico y posterior
seguimiento, del episodio agudo de HII en tres
niñas con edades entre 4 y 11 años. Todas acudieron con síntomas inespecíficos: Alteraciones visuales, cefalea, abdominalgia, visión doble y tortícolis.
Los estudios de neuroimagen fueron normales. Tras
la punción lumbar, la presión intracraneal estaba
elevada. Se realizó campo visual (CV) mediante
perímetro Octopus y medida de la capa de fibras
nerviosas (CFN) con OCT en todas las revisiones.
Resultados: La agudeza visual fue normal en todas
ellas, con paresia de VI par en dos casos. El estudio
de fondo de ojo reveló siempre un gran edema de
papila. La medida inicial de la CFN con OCT se
halló elevada, duplicando o triplicando los valores
normales. El seguimiento y tratamiento con predni-
Received: 16/12/05. Accepted: 17/7/06.
Departamentos de Oftalmología y Pediatría del Hospital Río Hortega. Valladolid. Spain.
1 Ph.D. in Medicine. Ophthalmology specialist.
2 Graduate in Medicine. Ophthalmology specialist.
3 Graduate in Medicine. Pediatrics specialist.
Paper presented at the LXXXI Congress of S.E.O. (Zaragoza 2005).
Correspondence:
Hortensia Sánchez Tocino
Servicio de Oftalmología. Hospital Río Hortega
Avda. Cardenal Torquemada, s/n
47010 Valladolid
Spain
E-mail: [email protected]
SÁNCHEZ-TOCINO H, et al.
follow up and the treatment with prednisone and azetazolamide was monitored by OCT, with a good outcome and return of the ONF levels to normal. In one
case, however, a recurrence was detected after three
months without treatment.
Conclusion: IIH in childhood is an uncommon
condition, often with a different presentation from
what is seen in teenagers and adults. OCT is a useful technique helping in both the diagnosis and the
follow-up of this disorder in children (Arch Soc Esp
Oftalmol 2006; 81: 383-390).
Key words: Optic coherence tomography in children, idiopathic intracranial hypertension, neuropathy in a child, papilledema, benign childhood
intracranial hypertension, pseudotumor cerebri.
INTRODUCTION
Idiopathic intracranial hypertension or pseudotumor cerebri (HII) is defined as an abnormal elevation of intracranial pressure which is not associated
to an expansive process or hydrocephalia and with
normal cerebro-spinal liquid (1,2). It expresses as a
papilledema frequently associated to small peripapillar hemorrhages, without afferent pupil defect and
little involvement of visual acuity, at least initially.
By means of three cases, this paper demonstrates
the usefulness of Optical Coherence Tomography
(OCT) as a diagnostic supplement and, above all, in
the follow-up of this paediatric pathology. OCT
allows observing an important increase in the thickness of the Nervous Fibre Layer (NFL), considerably greater than that found in previous neuritis
conditions.
SUBJECTS, MATERIAL AND
METHODS
This paper describes three cases of women aged
4-11 who attended the urgency ward due to nonspecific visual and systemic symptoms. In all cases,
a full ophthalmological study was made with measurement of visual acuity (VA) with the Snellen
test, study of eye movement, cover test, far dyplopia test with Worth lights, anterior biomicroscopy,
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sona y acetazolamida vía oral se realizó de acuerdo
a las medidas del OCT. La evolución fue buena con
progresiva normalización de los valores de grosor
en el OCT. Si bien en un caso, tras 3 meses sin tratamiento, se detectó mediante OCT una recurrencia
asintomática.
Conclusiones: La HII en edad pediátrica es una
entidad poco frecuente y diferente de la afectación
típica del adolescente y el adulto. El OCT es una
técnica objetiva y reproducible que puede ayudar a
completar el diagnóstico y, sobre todo, el posterior
seguimiento clínico y terapéutico de estos cuadros
en niños.
Palabras clave: Tomografía de coherencia óptica
en niños, hipertensión intracraneal idiopática, neuropatía en niños, papiledema, hipertensión intracranial benigna en la infancia, pseudotumor cerebri.
eye fundus with 90 Dp lens, visual field (VF) with
Octopus automatic perimeter (OCTOPUS, HaagStreit AG, Koeniz-Berne, Switzerland) and study of
NFL with OCT.
The thickness of the retina nervous fiber layer was
measured with Optic Coherence Tomograph (OCT3, Carl Zeiss, Meditec, Dublin, CA, USA). OCT is a
non-invasive image diagnostic method which carries
out objective and direct quantitative measurements
of the papilla and the NFL. It is based on an optical
principle known as low coherence interferometry
and utilizes an 820-nm wavelength light beam. A
part of the light beam goes to the retina and the other
to a reference mirror placed at a determined distance. The echoes obtained after reflecting off the retina are compared with those coming from the reference mirror, thus producing an interference which
is captured and measured by a detector. In this way,
two-dimension images are obtained which are compatible with histological images with an axial cross
section of approximately 10 µm and a depth of 2 mm
by means of scans which oscillate between 128 and
768 nm (3). Although the perfect condition for carrying out the scan is in midriasis, good images can be
obtained without dilating the pupil. For studying the
NFL structure, the OCT detects the anterior surface
of the NFL and the pigmentary epithelium of the
retina (RPE).
As the said structures are highly reflective, they
appear in red. In the NFL study, the parapapillar
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Usefulness of OCT in idiopathic intracranial hypertension in childhood
thickness parameters are automatically calculated
and assessed in the vertical and horizontal axis
along a circular scan. For making the measurements
we utilized the Fast RNFL Thickness (3.4) mode
under midriasis obtained with 1% cyclopentholate
eye drops (Colircusi cyclopegic 1% Alcon Cusí, El
Masnou, Barcelona, Spain). The measurements
were analyzed with the RFNL Thickness Average
Analysis protocol which is able to quantify the
mean thickness in total microns (µ), in 4 peripapillar sectors: inferior, superior, nasal and temporal
and in nine clock times; while the RNFL Thickness
Serial Analysis Report was utilized for studying the
differences in the thickness of the scans.
In all cases, the pediatrics service of our hospital
carried out a general analysis which included: hemogram, reactive protein C, rheumatoid factor, protein
gram, ANA, antiDNA, thyroid hor-mones, cortisole,
ASLO, serology against herpes virus, zoster, citomegalovirus, toxoplasmosis, legionella, coxiella,
chlamydia, mycoplasma, borre-lia, syphilis, brucella, salmonella, rickerttsia and hidati-dosis; imaging
studies: Computerized Axial Tomography (CAT),
Magnetic Nuclear resonance (MNR) and angioresonance; electrical-physiological tests; electroencephalography and a lumbar punction, assessing the
presence of proteins, glucose, cells and measuring
intracranial pressure. In all three cases, the studies
gave normal results excepting the intracranial pressure which was high. This pressure was taken in the
subarachnoid space by means of a hydraulic system
(liquid-filled column) in cm of water.
FINDINGS
Case 1
A ten-year old girl who attended our services due
to abdominalgia. The ophthalmological exploration
showed a VA of 1 in both eyes (BO), slight paresia
of the VI cranial pair which caused dyplopia in
extreme positions. The eye fundus evidenced a bilateral papillar edema (fig. 1).
The CV showed an increase of the blind spot.
OCT evidenced a diffuse thickening of the NFL
Fig. 1: Case #1: A. Bilateral papilledema and OCT image with initial NFL thickening in RE. B. Papilla and OCT image one month later in RE. Normalization of NFL after treatment.
ARCH SOC ESP OFTALMOL 2006; 81: 383-390
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SÁNCHEZ-TOCINO H, et al.
which maintains the typical double hunch pattern,
mean NFL thickness 206 µm and 108 µm right eye
(RE) and left eye (LE) respectively (fig. 1). The
neuroimaging techniques, the analyses and the biochemical study of the cerebro-spinal liquid (CSL)
gave normal results. Intracranial pressure was of 31
cm of H20. The Body Mass Index (BMI) was of
17,6 (percentage 50-75).
Case 2
A four-year old girl who attended due to dyplopia,
torticollis and Myodesopsia. Ophthalmological
exploration revealed a VA of 1 in both eyes. Paresia
in the VI pair of the left eye, torticollis with face on
right side. Pathological Worth lights test. The eye
fundus study revealed bilateral papilledema with
small wedge-shaped hemorrhage in the inferior pole
of the left eye. Considering the short age of the girl,
the visual fields could not be taken as reliable. OCT
showed a large increase of the NFL, with an average
thickness of 200 µm and 245 µm in RE and LE respectively (fig. 2). CSL; analytical study and neuroimaging gave normal results. The intracranial pressure was 45 cm H20. IMC: 18.6 (percentage 90-95).
Case 3
Eleven year-old patient previously diagnosed
with pigmentous retinitis who attended the checkup
practice referring blurred vision, dizziness and episodes of amaurosis fugax in the past few days. The
exploration revealed a VA of 0.7 in both eyes, without changes from previous controls. No alterations
in eye movements or dyplopia. The eye fundus
revealed bilateral papilledema, retro-equatorial
espicular pigment dispersion in the four quadrants
and normal-looking maculae (fig. 3). They showed
a peripheral restriction typical of pigmentous retinitis. OCT evidenced a large increase in NFL mean
thickness from 546 µm in the RE and 442 µm in the
LE (fig. 3). The analytical and neuroimage gave
normal results. A lumbar punction revealed normal
biochemistry and a pressure of 30 cm H20. BMI:
29,19, overweight (percentage 97).
In all cases treatment was established with oral
prednisone at a dosage of 1.5 mg/kg/day, Acethazolamide at 250 mg/8 hours, a potasium supplement and
gastric protector supplied by the Pediatric Service at
our Hospital. Both Papilledema and paresia of the VI
pair improved in both cases during the first week.
Other OCT tests were performed a week later, after
15 days, one month, and subsequently on a monthly
basis. Figure 2 shows OCT evolution in case 2, consisting of a progressive decrease in NFL thickness. In
case 3, the papilledema remained constant for eight
weeks. Maximum follow-up time was 9 months (fig.
3). Corticoids were gradually withdrawn as soon as
lab tests improved and there was significant reduction
in NFL thickness on the OCT and Acethazolamide
when NFL measurements were checked with OTC at
around 110 µm. In the first two cases, this was achieved approximately in the third month; in case 3 treatment was prolonged for 6 months.
In case 1, after 3 months untreated, a small transitional increase of NFL was detected by means of an
OCT, although in the absence of symptoms, no treatment was prescribed. Nevertheless, in case 3, two
months after treatment was completed there was a
decrease in NFL thickness, down to 75 µm on the
right eye and 67 µm on the left (fig. 4) which reflect
an evolution towards a certain degree of atrophy.
During the long-term 1-year follow-up, OCTs
did not reveal in neither case 1 nor 2 any significant
recurrence requiring new treatment.
DISCUSSION
Fig. 2: Case #2: Evolution of NFL: Initial, at 2 weeks, 3
months and 6 months.
386
HII is defined as an entity leading to an elevation
of the intracranial pressure without apparent cause
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Usefulness of OCT in idiopathic intracranial hypertension in childhood
Fig. 3: Case number 3: A. Bilateral Papilledema. B. OCT image with initial NFL thickening in A.O. C. OCT with NFL
during the 6th month in A.O.
and with a normal image study of the central nervous system. The illness is well described in adults
who characteristically show a female predominance
and a link with obesity. In children, these characteristics may differ. The same gender distribution is
present; the series published by Orssaud describe
how 47 percent of the 30 patients surveyed were
girls under 13, whereas 75% of those aged over 13
were women (4.5). Among adolescents, as in
adults, this illness is linked to obesity and is primarily present among females.
In prepuberal children, HII appears generally
associated with cephalea, diplopia, strabismus and
in certain cases also nape rigidity. Other general
symptoms have been described as well, such as irri-
tation, agressivity, behaviour alterations or drowsiness (6).
Baker reported a loss of visual acuity (between
13 and 38 percent) in children with HII (7).
Cinciripini found visual field defects in 85% of
eyes, the most frequent being an increase of blind
spots (6). No loss of VA was found in any of the
cases presented herein. There was an initial CV
defect in case 1 which subsided fully. In case 3,
damage the visual field was linked to the pigmentary retinitis already present. No drusas were detected in the optical nerve either through tomography
or OCT.
Although most published series describe a full
recovery of visual acuity, strabismus and CV
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SÁNCHEZ-TOCINO H, et al.
Fig. 4: Case number 3. Evolution of NFL over a 9 month
period.
defects, there are cases of permanent loss of VA(4)
or visual field (6); diagnosis and early treatment are
very important for fully tackling this diagnosis. In
our series, only case number 3 showed a permanent
loss of NFL which can be interpreted as a consequence of an acute HII without VA alteration.
Nevertheless, based on the patient’s previous pathology and without prior OCT, we could not reject the
possibility that the result obtained from measuring
NFL existed from the very beginning. Other authors
already described the impossibility of knowing via
OCT whether the reduction in fiber thickness of the
optical nerve is due to decrease of the edema or to
fiber atrophy (8). Nonetheless, when linking OCT
and other findings such as visual field, it proves to
be very useful for the follow-up of patients with
papilledema (8).
The papilla normalizes usually at around 4
months if treatment was undertaken promptly
enough. But in some cases evolution can lead to
optical nerve atrophy (6). Nevertheless, there is no
correlation between the papilla edema and the
increase in pressure, or between the latter and the
risk of an alteration in visual functions. On the other
hand, CV alterations are not characteristic of this
diagnosis (4).
Although OCT does not help to clearly identify a
papilledema, especially if it is a light, pseudopapilledema, a congenital elevation of the optical nerve,
as proven by other authors (9), since it only detects
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an increased thickness in the fiber layer around the
optical nerve. Even in those cases where we detect
in the optic fundus a papilledema together with a
more or less evident migraine or without decrease
in vision, OCT will not prevent the performance of
neuroimaging tests; nonetheless, it will allow us to
do the follow-up until achieving stabilization of the
diagnosis (8). Kar-ma et al. (9) also point out the
likelihood that the thickness of nerve fibers in
patients suffering from a more severe case of papille-dema could be greater with significant statistical
differences in eyes affected by pseudopapilledema.
The present review shows that OCTs are very
useful tests for HII, since they are objective, noninvasive and reproducible, they can be performed
on children and allow supporting diagnoses in face
of unspecified symptoms and, above all, they have
proved to be very useful during follow-up and
assessment of therapeutic efficacy on papilledema
as illustrated by the normalization of NFL. Similarly, they have allowed for the detec-tion of recurrences and the discovery of chronic sequels after
an acute episode of HII.
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