Treatment by agents with measurement ofthe blind spot as ... · JournalofNeurology, Neurosurgery, andPsychiatry, 1976,39, 627-639 Treatment ofbenign intracranial hypertensionby dehydrating

Journal ofNeurology, Neurosurgery, and Psychiatry, 1976, 39, 627-639

Treatment of benign intracranial hypertension bydehydrating agents with particular reference to themeasurement of the blind spot area as a means of

recording improvement

ANTONY JEFFERSON AND JANET CLARK

From the Department of Neurological Surgery, The Royal Infirmary, Sheffield

SYNOPSIS A series of 30 patients (28 females : 2 males) presenting with benign intracranialhypertension is reported. It is shown that the papilloedema may be resolved in as little as six weeksby the use of dehydration therapy. Evidence is presented that this method can restore to normal avisual acuity which is as low as 6/24 or even 6/36. It is concluded that surgery is never required in themanagement of this condition. It is strongly recommended that serial blind-spot measurementsshould be used routinely to assess the effectiveness of therapy. Fluorescein angiography has a placein diagnosis among a small proportion of these patients.

The existence of papilloedema in the absence ofan intracranial mass poses problems which areno less intriguing for the diagnostician than tothe person responsible for their treatment. Oneof the interesting features of so-called 'benignintracranial hypertension' is that, while it isharmless to life, it can be devastating to visionfor, at its worst, bilateral permanent blindnessmay ensue.The purpose of this paper is to show the value

of measuring the blind spots; also to record theresults of the various methods used in themanagement of this condition in a series of 30patients treated in this department over the past17 years.We propose a simple formula which may be

easily employed to convert the measurements ofa blind spot (as charted on a Bjerrum screen)into an area. The convenience of working with asingle figure corresponding to the area becomesimmediately obvious as soon as sequentialreadings are studied.

(Accepted 10 February 1976.)

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METHODS

All individuals have been studied using a Bjerrumscreen at 2.0 metres. A white test object 16 mm indiameter has been consistently used. This ratherlarge object was chosen so that the patient shouldhave no doubt about its presence when it came intosight. The patients were all instructed to respond assoon as they saw the rim of it and not to wait untilthe whole of the test object had become visible. Thesubject has worn spectacles when appropriate-thatis, when the wearing of glasses made the responsesmore consistent.

Patient fatigue would make it a self-defeatingexercise to attempt to plot the blind spots by meansof so many points alongtheirborderthat acontinuousline could be obtained from them. Because of this,we have plotted no more than eight points whichprovide four measurements-vertical, horizontal,and two diagonals (Fig. la). The lengths are thendivided by two to give us four dimensions-namely,a, b, c, d (Fig Ib). The following formula is then ap-plied to obtain the area of the octagon:

(a+b) (c+d)a/2

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Antony Jefferson and Janet Clark

Nasal 1 2

FIG. 1 (a) Order ofplottingthe eight points from whichthe blind spot area iscalculated. (b) Half thehorizontal, vertical, anddiagonal dimensions are usedin calculating the area of theblind spot.

4

(a) (b)

We have found that this octagon provides anapproximation to the true blind spot which hasproved itself to be perfectly practicable.'One of the essentials with a method employing

serial measurements is to know that the findings arelikely to be consistent. Accordingly, we made thesimple experiment of studying the relationshipbetween blind spot area and distance from thescreen. If the technique is consistent the inversesquare law should apply. Figure 2 shows that itdoes-within the limits of observer error. Becauseof the problems which could arise from slightlydiffering techniques, all the blind spots (with onlyfour exceptions) have been charted by one individual(A.J.).

In order to obtain information about the 'normal'we studied a series of 30 individuals without com-plaints and with no specific ocular symptoms (thisgave us a total of 53 normal eyes). The mean blindspot area was 67.5 sq. in. (1 sq. in. = 6.45 cm2). Therange of blind spot area which we have accepted asnormal was obtained by taking twice the standarddeviation (SD= 13.3 sq. in.) on either side of themean. Thus we concluded that areas between 41 and94 sq. in. could be considered normal.The patients included in this study have consisted

of all those referred to one of us (A.J.) during thepast 17 years in whom bilateral (and approximatelysymmetrical) papilloedema was observed in the

1 It may be that it would have been equally satisfactory to employ theformula or .rt r' for an elipse. We rejected this possibility because theblind spot may be irregular and it seemed to us pretentious to apply aformula which assumed the existence of more than the eight pointswhich were actually measured. In fact, it seems to make very littlepractical difference which formula is applied to any one patient.

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FIG. 2 Area of the blind spot which for one normalindividual was recorded at seven different distances.Note: Ordinate= square of distance (cm); abscissa =blind spot area.

absence of any intracranial pathology. Under thisheading we scrutinised the notes of 62 patients; 10of these had to be excluded from further considera-tion merely because of insufficient data. We haveclassified and tabulated the remaining 52 patients(Table 1) so that the reader can see the backgroundfrom which we have drawn the patients with whomthis report is concerned. We have excluded childrenfrom this study, firstly, because attempts to measuretheir blind spots have not shown consistent results.Secondly, we suspect that papilloedema whichaccompanies children's febrile illnesses has a dif-ferent pathogenesis, because it disappears very

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Treatment of benign intracranial hypertension by dehydrating agents

rapidly-for example, in two to four weeks-afterresolution of the primary illnesses. These childrenoften received no treatment other than antibiotics.

This paper is concerned with the group of 30 adultpatients suffering from papilloedema without adetectable cause.

TABLE 1ANALYSIS OF TOTAL CASE MATERIAL FROM WHICH

30 PATIENTS WITH BENIGN INTRACRANIALHYPERTENSION WERE DRAWN

Number ofpatients

MAfale Female

Insufficient data 2 8Children (under 16 years)

a. Classical otitic hydrocephalus 2 2b. Upper respiratory or other infection 3 2c. No obvious cause 1 3d. Steroid administration 1 0

Adultsa. Classical otitic hydrocephalus 1 0b. Mistaken diagnosis: i.e., fundi

abnormal but not papilloedematous 2 4c. Unclassified 1 0d. Papilloedema of unknown origin

(benign intracranial hypertension) 2 28

The age and sex distribution of these patients isset out in Fig 3. This shows that the patients werepredominantly female and that although almosthalf of them were aged less than 26 years the olderage groups were also involved.

The diagnosis of non-tumour papilloedema wassubstantiated in some patients after special neuro-radiological investigations-for example, angio-graphy or pneumoencephalography-but in theremaining patients the diagnosis was made onclinical grounds aided by the echogram, the EMIscan, the gamma-scan, and by plain radiographs ofthe skull.The patients with whom this report is chiefly

concerned received treatment according to themethods listed in Table 2. The majority of thefemale patients were overweight (mean weight=78 kg), and in such patients the therapy listed hasbeen combined with a reducing diet.

TABLE 2ANALYSIS OF THERAPY USED IN MANAGEMENT OF

BENIGN INTRACRANIAL HYPERTENSION

Sole or chief therapy Number ofpatients

Subtemporal decompression(only for patients treated before 1958) 5Dehydratiotn therapy 25Steroids 0

RESULTS

After the chosen therapy was established thepatients were reviewed at intervals in the out-patient clinic until it became clear that thepapilloedema had resolved completely. Two

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FIG. 3 Age anid sexdistribution of 30 patientswith papilloedema.

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females have suffered a second 'attack' of thisdisorder; two years and three years, respectively,separated the two episodes.The preferred treatment has altered with the

passage of time. Initially, before it was realisedhow effective dehydration therapy could be, werelied upon a subtemporal decompression to savethe eyesight. This was a time-honoured andeffective technique, but it has the disadvantagethat it has now been shown to be unnecessaryand the operated patients frequently continuedwith an unsightly (and sometimes tender) bulgein the decompression area for many years.The dehydrating agent has been changed over

the years and Table 3 lists the methods used.All patients treated by dehydration have beeninstructed to limit their daily fluid intake to900 ml. Most of the patients treated with hydro-flumethiazide and with chlorthalidone have beengiven potassium supplements.

TABLE 3ANALYSIS OF VARIOUS DEHYDRATING AGENTS USED

Sole or chief dehydrating agent Number ofepisodes*

Oral urea (1.0 g/kg/day) 1Oral glycerol (1.0-1.5 g/kg/day) 7Hydroflumethiazide (100 mg alternate days) 8Chlorthalidone (200 mg alternate days) 11

* There were 27 'episodes' among 25 patients not subjected to surgery.

The patients' blind spots were calculatedaccording to the formula already described andthe results of treatment have been plotted.Examples of the findings are shown in Figs. 4,5, 6, 7, 8, and 11. The shaded area bounded byhorizontal dotted lines near the bottom of eachgraph indicates the range of the normal blindspot area. In this, and in all subsequent graphs,filled circles refer to the right eye, open circlesto the left one. The rectangle marked 'preg-nancy' terminated with delivery. The durationand nature of the therapy used is indicated byrectangles marked in the upper part of the charts.The patient's weight in kg is shown at intervalsby the figures above the small black triangles.

Figure 4 shows the effectiveness of a sub-temporal decompression. The vision of the lefteye was never affected, but that of the right eye

was 6/12 initially and was restored to 6/6 at theend of the therapy. However, this patient wasleft with a persistent, unsightly bulge in thesubtemporal region which was still present whenshe was seen for another reason 14 years later.

Figure 5 shows that by using oral urea aneffect similar to that which results from surgicaldecompression is eventually achieved. In thispatient it will be noticed that a relapse followedthe cessation of treatment and an additionalcourse of urea was necessary.

Figure 6 shows the most dramatic responsewhich we observed after the use of oral glycerol.This patient was admitted to hospital with ahistory of visual failure which had developedduring the preceding eight weeks. For threeweeks a left external rectus weakness had beenpresent. The graph shows that the papilloedemahad virtually disappeared at the end of twomonths. Her visual acuities at the end of treat-ment were 6/9 auid Jaeger 1 bilaterally. Theresolution of papilloedema when using glycerolwas not always so prompt or so complete.

Figure 6b illustrates an example where verylittle progress was achieved by glycerol buteventual resolution accompanied treatment withhydroflumethiazide.

Figure 7a shows the best response seen whenusing hydroflumethiazide, while Fig. 7b shows aless impressive result, but one which is ofinterest because a relapse followed when thetreatment was stopped before the papilloedemahad fully resolved.

Figure 8 shows a striking resolution of theenlarged blind spots in a young pregnant girlwho presented with visual failure. At the start oftreatment this girl's visual acuities were 6/9right and 6/24 left. After only four days treat-ment her acuities had already improved to 6/6right and 6/18 left. Six days later-that is,only 10 days after the dehydration regimen hadbeen instituted-the visual acuities were 6/6bilaterally and N,5 right, N,8 left. The weightgain (79.0 kg-80.6 kg) in the Figure is pre-sumably related to pregnancy because thispatient lost 2 kg in her first week in hospitalwhich suggested that she had an excess of bodywater of which she rid herself promptly inresponse to treatment. Figure 8b shows her rightoptic disc four days after therapy began, andFig. 8C shows the appearance six weeks later.

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97-3 KgIV

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FIG. 4 Blind spot areas of a patient whose papilloedema was treated by subtemporal decompression. Notethat there was still a considerable enlargement of the blind spot two months after the operation.

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showing relapse. The blindspot areas of a patient whosepapilloedema was treated withoral urea.

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19Time (months)

It can be seen that the papilloedema hadresolved completely by the end of six weeks, butoptic atrophy had developed. In spite of the opticatrophy, the visual acuity was fully preserved at6/5.Through the courtesy of Mr Ian Strachan,

fluorescein angiograms have been performed ona number of our patients. These were carried outto help record the progress of the disease. Figure 9shows the appearances, early and late, after the

intravenous injection of 2.5 ml 25% fluorescein.The figure also includes our measurements ofthe blind spot area. The particular pairs of photo-graphs would seem to indicate some correlationbetween the severity of the abnormalities and thesize of the blind spot; however, we have in-sufficient data to say more than this.

Figure 10 shows how clearly fluoresceinangiography demonstrates the resolution of thepapilloedema at the conclusion of treatment.

SUB-TEMPORAL DECOMPRESSION

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Antony Jeffersont and Janet Clark

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FIG 6 (a) Response to glycerol. The blind spot areas of a patient wt'hose papilloedema was treated with oralglycerol (1.5 g/kg/day). Note that in this patient the blind spots never receded to within the normal range.(b) Response to glycerol showing relapse. Blind spot areas ofa patient who did not respond satisfactorily to oralglycerol and who was eventually cured by hydroflumethiazide.

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FIG. 7 The blind spot areas of patients whose papilloedema was treated with hydrofluinethiazide 100 mgevery second day (see text): (a) response, (b) response with relapse. Note in (a) how at the end of treatmentthe blind spot areas remain at the utpper limit of normal. Incidlentally, the consistency of the measurementonce the papilloedema had resolved confirms the validity of the method.

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Female aged 9 years

done

0-6Kq 75-5Kg_IV FIG. 8 (a) Response to chlorthalidone. The

blind spot areas ofa young pregnant girl withvisual impairment arising from papilloedema.Note that the blind spots are almost normal afteronly six weeks.

60 2 3 4Ti me ( months)

FIG. 8 (b) Same patient's right optic disc after folur days' therapy: the blind spot at this stage measured333 sq in. (c) The same, six weeks later. The blind spot was now 93 sq. in.

We have attempted to relate the area of patho-logy outlined by the late fluorescence of the discto the size of the blind spot. However, we haveto report that in the few cases where this waspossible there was no consistent relationship

between these areas.It was mentioned above that vision may

frequently become seriously impaired in thisdisorder. Indeed, in a series of nine untreatedpatients whose notes have been traced in the

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IFIG. 9 Fluorescein angiograms of three patients; arterial phase above; venous phase below. See text.

records of this hospital, two (22 Y.) progressed tonear blindness. However, it appears that prompttherapy is consistently followed by improvementin the visual acuities, although the eyes mayremain permanently slightly damaged by thedisease. For example, one patient had initialvisual acuities of 6/12, 6/36 and her acuities aftertreatment improved only to 6/9, 6/12.

Table 4 lists the data concerning the pre- andpost-therapy visual acuities in all those patientspresenting with impaired vision. (The remaining17 patients-those presenting with visual acuity6/6 or better-continued in the same category,although two of them showed a post-treatmentacuity of 6/6 as compared with a pre-treatment6/5). There were only two patients whose visiondid not recover to at least 6/9; one of them hadhad a diagnosis of 'lazy eye' established manyyears earlier. The fact that this type of papillo-edema may be associated with some residualtissue damage would explain our observationthat, at the end of treatment, when the papillo-edema had fully resolved, not all of our patients

had blind spot areas within the 'normal' range.This observation may well be related to theappearance of optic atrophy which is sometimesnoticeable at the conclusion of treatment eventhough visual acuities are preserved (cf. Fig. 8c).Our data are not sufficiently large to let us drawabsolutely firm conclusions, but it appears thatthe patients whose blind spots are initially muchenlarged-for example, over 300 sq. in.-arethose most likely to show some permanentincrease in blind spot size.

It is sometimes difficult satisfactorily to assessthe duration of treatment required to obtaincomplete resolution of the papilloedema-thatis 'time-to-cure'. This difficulty has arisenbecause the patients at this stage are being seenat three to four week intervals as outpatientsand no information is obtained between visits.Sometimes also, in the earlier part of this study,a patient would have the treatment changedbecause the first agent used had been seen to beineffective; in such a situation one obviouslycould not speak of a 'time-to-cure'. We have

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Bli

Treatment of benign intracranial hypertension by dehydrating agents 6

FIG. 1O Fluorescein angiograms& -*^- offemale, aged 16 years.

Arterial phase above; venousphase below. Left, before and.right, after treatment.

Before treatment After 6 wk treatment with chlorthalidoneind spot= 181 sq. in. Acuity 6/4 Blind spot=71 sq. in. Acuity 6/5

TABLE 4

TABULATION OF VISUAL ACUITIES BEFORE AND AFTER TREATMENT OF ALL THOSE PATIENTS WHOPRESENTED WITH SOME VISUAL IMPAIRMENT

Patient Initial acuities Final acuities

R eye L eye Wearing R eye L eye Wearingcorrecting correcting

lenses lenses

S.C. 6/9 6/7.5 6/6 6/6E.G. 6/9 6/6 6/4 6/4K.L. 6/36* 6/36 6/36* 6/6P.G. 6/12 6/36 6/9 6/12N.G. 6/9 6/12 + 6/6 6/9 +I.H. 6/6 6/24* 6/5 6/9*P.M. 6/9* 6/4 + 6/9* 6/5 +M.D. 6/6 6/9 + 6/5 6/6D.N. (1) 6/9 6/9 6/6 6/6D.B. 6/9 6/24 6/4 6/5J.F. 6/12 6/7.5 6/5 6/6D.N. (2) 6/6 6/9 6/5 6/6P.N. 6/12 6/4 + 6/6 6/5 +P.P. 6/6 6/9 6/4 6/4

* Known lazy eyes.(1) First occasion. (2) Second occasion.

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come to believe that chlorthalidone is superiorto hydroflumethiazide because the mean 'time-to-cure' with chlorthalidone has worked out in10 patients at 12 weeks. The rapidity and con-sistency with which the papilloedema hasresolved in the group treated with chlorthalidoneis shown in Fig. 11 in which the blind spot areasof 11 patients are superimposed on one chart.

DISCUSSION

Papilloedema occurring without tumour hasbeen widely accepted as capable of causingserious visual impairment. For example, Foley(1955) reported permanent visual impairment in23 % of his cases with a similar type of papillo-edema. Some untreated cases which we haveculled from the records of this hospital, althoughfew in number, provide a comparable figure

s5o-,

(22 %). If one accepts that there is every reasonto take this condition (which is 'benign' as tolife) very seriously then one should concentrateon devising the best method of treatment.Over the years surgical methods have proved

themselves to be effective. The neurosurgicaltechniques adopted have been unilateral or evenbilateral subtemporal decompressions, posteriorfossa decompression, or ventriculoatrial shunt-ing.

All these methods are reported to be effective,although many authors from Dandy (1937)onwards have noted that with these patients thearea of the subtemporal decompression some-times remains bulging in an unsightly mannerfor many months or even years. More recently,following the experimental work of Hayreh(1964), there have been reports from ophthal-mological surgeons who have effectively relievedthe papilloedema by incising the optic nerve

FIG. 1I1 The blind spot areas of 10 patientstreated with chlorthalidone. Note that the timescale differs from that used in earlier figures. Inthis figure the plot for each patient is compiledfrom the mean of the blind spot areas of thetwo eyes.

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sheath (see, for example, Davidson, 1969, orGalbraith and Sullivan, 1973).

In the literature (Paterson et al., 1961) the ideahas developed that high doses of steroids arevaluable in the management of this type ofpapilloedema. They have deliberately beenavoided in our patients because it was quicklyrealised that dehydration was effective and de-hydrating agents seemed less potentially danger-ous than steroids. We have received personalcommunications (Winn, 1974; Hulme, 1975) inthe form of tracings obtained during the con-tinuous monitoring of intracranial pressurewhich show that in two young female patientssuffering from this syndrome high doses ofsteroids did not lower the intracranial pressure,whereas dehydrating agents did so.With regard to the treatment, it may be that

satisfactory loss of weight by the obese femaleis an important factor associated with theresolution of the papilloedema. Certainly thefactor of obesity when combined with beingfemale has been a consistent presenting featureamong an otherwise assorted group. Variousauthors (e.g. Greer, 1965) have drawn attentionto this previously. Perhaps obesity has also beena factor, if not 'the' factor, underlying the rarefamilial occurrence of this disorder (Howe et al.,1973).We started with the notion that this syndrome

was seen chiefly in the overweight young femalewith a recent pregnancy or with some menstrualdisorder. Our own material certainly shows thatthe young female is more frequently affected thanis the older woman (cf Fig. 3). Perhaps thebelief that recent pregnancy or a menstrualdisorder is an important factor arises fromnothing more than the fact that both theseevents are fairly common in the younger female(see also Johnston and Paterson, 1974). Certainly,we no longer regard these features as a relevantpart of the syndrome. However, we do considerthat there is a metabolic element which underliesthis condition and in this respect our theorisingfollows along one or more of the trails embarkedupon by Thomas (1933) and by Oldstone (1966).Although this syndrome predominantly affects

the female, a small proportion of male patientsalso suffer from papilloedema without an intra-cranial mass (cf. Dandy, 1937; also Boddie et al.,1974). With only two male patients we can have

no views as to whether the syndrome in the malediffers in any important aetiological factors fromthe one seen in the female. Furthermore, even inthe female, we have no certain knowledge thatthis syndrome encompasses an homogeneousentity.We must emphasize that we have rejected

from consideration all patients with an infectiveelement in their presentation-that is, allclassical and not-so-classical examples of 'otitichydrocephalus'-also all patients with mono-cular or widely asymmetrical papilloedema.It will be recalled that Table 1 demonstrated thisin detail. With regard to the entry 'Mistakendiagnosis' in that table, we have found theadvent of fluorescein angiography (e.g. Milleret al., 1965, also Rosen, 1969) ofvery great value.Occasions on which we would in the past haveprescribed treatment and followed up patientsfor many months can be eliminated by thejudicious use of fluorescein coupled whennecessary with stereoscopic colour photo-graphs of the disc. Because fluorescein angio-graphy distresses some patients, we would holdback from recommending it routinely. However,if the clinical presentation is unusual, or theappearance of the fundi not really typical, or theblind spots are not initially greatly enlarged-forexample, no more than about 120 sq. in.-thesepatients should be referred for fluoresceinstudies. When used, fluorescein should beemployed early because, in our experience,resolving papilloedema may very easily bemistaken for drusen of the disc. Thus, fluoresceinused late may serve to confuse and not to clarifythe issue.With regard to the measurement of the blind

spots, a study of the literature suggests that therehas been very little systematic usage of blind spotsize as a means of recording the severity ofpapilloedema since Loyal Davis (1929) reportedhis findings. He was, of course, recording theresolution of papilloedema after the excision ofintracranial masses. So far as we are aware,there are no published reports of blind spot sizebeing used as a means of monitoring the reso-lution of non-tumour papilloedema. Indeed,among the very few other clinicians interested inrecording blind spot size as a matter of routinehave been Benshtein (1961) and Ustinova (1962);while Shumilova (1962) observed a diminution

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in the size of the blind spot after dehydration ofthe hypertensive patient. Because of the apparentlack of general interest in blind spot measure-ment, we have concluded that it is not generallyrealized how easily these measurements may beobtained in any cooperative subject, nor is itappreciated how consistent they are. The graphsreproduced in the present paper speak forthemselves as regards consistency. (It must berecalled that all the plots were obtained by oneobserver, but two or more equally experiencedobservers might well find that they obtainedclosely comparable if not identical results). Weheartily commend the use of serial measure-ments of the blind spot to all those who have thecare of this group of patients, and we are surethat such measurements are essential in theeffective management of non-tumour papill-oedema.

In recommending the measurement of theblind spots as a means of following the resolu-tion of papilloedema, we must point out thatthere is not a 1 :1 correlation at the beginning andat the end of treatment between the area of theblind spot and the area containing visibleabnormalities on the fluorescein angiogram. Itmay very well be that the pathological featureswhich enlarge the blind spot include damage tothe sensory layer of the retina which is notnecessarily visible to the ophthalmoscope. Thefact that the blind spots have not alwaysreturned to normal in our treated patients couldbe the result of permanent peri-papillarydamage, or alternatively could be a manifesta-tion of the optic atrophy which we have some-times noted-for example, Fig. 8c.We have already referred to difficulties in

diagnosis with specific regard to the optic fundi,but it is necessary to allude briefly to the clinicaldiagnosis. The criteria we have followed havebeen as follows. The clinical picture must be oneof raised intracranial pressure only-that is,with the exception of a mildly unsteady gait,there must be no abnormal neurological signsexcept either VIth nerve palsy (unilateral orbilateral) or those relating to the papilloedemaitself. The radiographs of the skull in childrenmay show suture separation, but in adults wewould advise against accepting the diagnosis ofnon-tumour papilloedema if there are anyindications of chronic raised intracranial pres-

sure. For example, erosion of the pituitary fossais a feature of long-standing raised intra-cranial pressure and simply will not be found inconjunction with a relatively short history (inthis series its mean duration was 14 weeks),which suggests that this type of papilloedemadevelops over a short period of time. In a fewpatients (for example, Fig. 8 above) the historywas as short as three weeks and we believe thatthis very short history has a diagnostic valuewhen one is confronted by a patient with flagrantpapilloedema and no other abnormal neuro-logical signs except for those which could resultfrom raised intracranial pressure. Apart fromplain radiographs (and always provided that theabove-mentioned clinical criteria are strictlyfollowed) the diagnostic investigations which willbe necessary from now on are as follows. In adepartment with an ultrasonic A-scan which isdeployed with reliable accuracy this investi-gation alone is of great value. When a patientwith florid papilloedema can be shown by theA-scan to have a central undilated 3rd ventricleone knows that if the result is correct then anintracranial mass has virtually been excluded.However, since so much is at stake for thepatient, a gamma-scan has often also beenperformed. In the future a CAT scan (EMIscan) will probably become the final arbiter inthe diagnosis of these patients and its use shouldobviate the need for both angiography and fordelineation of the ventricles.

In the literature, a restricted fluid intake, asalt free diet, diuretics, and acetazolamide havebeen shown to have a place in the treatment ofbenign intracranial hypertension. The contri-bution of the present writers is to have statedcategorically that surgery is not required in thetreatment of this condition and to stress that thisholds true even when the vision has begun to fail.Although our results show that a certain amountof optic atrophy frequently follows an advanceddegree of papilloedema in this condition, thereappears to be so much 'spare capacity' amongthe optic nerve fibres that in practice and withvery few exceptions the visual acuities at the endof therapy have either been maintained intact, orhave substantially recovered.The message of our work is to stress that

dehydration therapy alone is sufficient treat-ment for this condition. Chlorthalidone seems to

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be the best agent that we have employed to date,but we hold no special brief for it as a permanentor inevitable first choice. One of the difficulties infinding the most effective therapy is that thesepatients are generally so fit and well that we haveoften seen no need to admit them to hospital.Even when they have been inpatients the pro-priety of inserting an intracranial pressuremeasuring device in order to study the compara-tive efficacy of various dehydrating agents mustbe in doubt, so that, with a relatively rare condi-tion (only 30 patients in 18 years), also a condi-tion in which 'invasive' measuring techniquesmay be unacceptable on ethical grounds, pro-gress towards the selection of the perfect de-hydrating agent may have to be slow. However,we would suggest that slow progress in thisrespect is not vitally important because all theforms of therapy used in this series have beeneffective in saving vision. Once reasonablyefficient dehydration has been set in motion, itappears that vision will be preserved providedthat treatment is not stopped before the condi-tion has resolved. This correlates with the fact,well known to surgeons who practised themethod, that, although subtemporal decom-pression was effective in preserving vision, it didnot always resolve the papilloedema rapidly.

We would like to record our thanks to the Ryder BriggsMemorial Foundation for financial assistance to one ofus (J. C.) during the preparation of this paper. We arealso grateful to Mr A. L. Foster for his skill and care inpreparing the graphs, and to Mrs M. Saynor, who tookthe fundus photographs.

REFERENCES

Benshtein, I. Yu. (1961). On the method of measuring theblind spot area. (Russian). Vestnik Oftalmoloqii, 74,45-46.

Boddie, H. G., Banna, M. M., and Bradley, W. G.(1974). 'Benign' intracranial hypertension. A survey of

the clinical and radiological features, and long termprognosis. Brain, 97, 313-326.

Dandy, W. E. (1937). Intracranial pressure withoutbrain tumour. Annals of Surgery, 106, 492-513.

Davidson, S. I. (1969). A surgical approach to plero-cephalic disc oedema. Transactions of the Opthalmo-logical Society of the U.K., 89, 669-690.

Davis, L. (1929). The blind spots in patients with intra-cranial tumours. Journal of the American MedicalAssociation, 92, 794-798.

Foley, J. (1955). Benign forms of intracranial hyperten-sion: 'toxic' and 'otitic' hydrocephalus. Brain, 78, 1-41.

Galbraith, J. E. K., and Sullivan, J. H. (1973). Decom-pression of the perioptic meninges for relief of papille-dema American Journal of Opthalmology, 76, 687-692.

Greer, M. (1965). Benign intracranial hypertension. 6.Obesity. Neurology (Minneap.), 15, 382-388.

Hayreh, S. S. (1964). Pathogenesis of oedema of the opticdisc. British Journal of Opthalmology, 48, 522-543.

Howe, J. G., Saunders, M., and Clarke, P. R. R. (1973).Familial benign intracranial hypertension. ActaNeurochirurgica (Wien), 29, 173-175.

Johnston, I., and Paterson, A. (1974). Benign intracranialhypertension. I. Diagnosis and prognosis. Brain, 97,289-300.

Miller, S. J. H., Sanders, M. D., and Ffytche, T. J.(1965). Fluorescein fundus photography in the detec-tion of early papilloedema and its differentiation frompseudo-papilloedema. Lancet, 2, 651-654.

Oldstone, M. B. (1966). The endocrinological aspects ofbenign intracranial hypertension Archives ofNeurology(Chic.), 15, 362-366.

Paterson, R., de Pasquale, N., and Mann, S. (1961).Pseudotumor cerebri. Medicine (Balt.), 40, 85-99.

Rosen, E. S. (1969). Fluorescence Photography of theEye, pp. 345. Butterworths: London.

Shumilova, V. G. (1962). Changes in the blind spot andocular fundus in arterial hypertension. (Russian).Soviet Medicine, 25, 147-150.

Thomas, W. A. (1933). Generalized edema occurringonly at the menstrual period. Journal of the AmericanMedical Association, 101, 1126-1127.

Ustinova, E. I. (1962). On the method of registrationand measurement of the blind spot. (Russian). VestnikOftalmoloqii, 75, 49-51.

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Treatment by agents with measurement ofthe blind spot as ... · JournalofNeurology, Neurosurgery, andPsychiatry, 1976,39, 627-639 Treatment ofbenign intracranial hypertensionby dehydrating