Case report

Anton’s syndrome: a rare and unusual form
of blindness
Faisal Bashir Chaudhry,1 Samavia Raza,2 Usman Ahmad3
1

Stroke Medicine, John Radcliffe
Hospital, Oxford, UK
2
Radiology Department, John
Radcliffe Hospital, Oxford, UK
3
Gastroenterology, Hull and East
Yorkshire Hospitals NHS Trust,
Hull, UK
Correspondence to
Dr Faisal Bashir Chaudhry;
​faisalbchaudhry@​gmail.​com
Accepted 21 November 2019

SUMMARY
Anton syndrome is characterised by visual anosognosia.
It results from damage to both occipital lobes, while the
anterior visual pathways remain intact. We describe four
cases of Anton’s syndrome. First case is that of a 73-­year-­
old woman, who presented with two separate events
of intraparenchymal brain haemorrhage, 4 years apart.
Her first stroke affected the left and second affected
the right occipital lobe. Bilateral occipital lobe damage
resulted in cortical blindness. Second case is an 88-­year-­
old man, who suffered from two ischaemic strokes,
2 days apart. Each stroke involved one posterior cerebral
artery. This resulted in bilateral occipital and temporal
lobe infarcts. Third case is a 64-­year-­old woman with
chronic renal failure, who suffered bilateral occipital lobe
infarction after haemodialysis, due to posterior reversible
encephalopathy syndrome. Last case is that of an
80-­year-­old woman who suffered a basilar artery stroke,
resulting in bilateral thalamic, temporal and occipital
lobe infarction.

Background
Anton Babinski syndrome is characterised by blindness, without the self-­awareness of blindness. The
anterior visual tracts are intact and lesion is in
the posterior cerebral cortex, located in occipital
lobes. Patients is in complete denial of visual loss.
This lack of insight poses an increased risk of falls.
Confabulation is a major part of the syndrome.
In a bookish picture of Anton syndrome, area of
damage is confined to occipital lobes only. In real
life, parts of the brain either in close proximity to
occipital lobe or those sharing a common blood
supply are also affected. This results in a wide array
of symptomatology ranging from but not limited to,
cognitive impairment, somnolence and drowsiness.
This may complicate an already challenging clinical
picture. Loss of vision has a major impact on rehabilitation after a stroke.

Case presentation
© BMJ Publishing Group
Limited 2019. No commercial
re-­use. See rights and
permissions. Published by BMJ.
To cite: Chaudhry FB,
Raza S, Ahmad U. BMJ Case
Rep 2019;12:e228103.
doi:10.1136/bcr-2018228103

A 73-­
year-­
old woman was brought to the emergency department by with symptoms of a sudden
onset headache, vomiting and increased confusion.
Patient denied any visual symptoms. While taking
history, clinician noted her lack of eye contact.
On examination of visual field by confrontation
method, it became apparent that she could not
reliably see in any quadrant of visual field. She
had no facial droop and was moving all four limbs.

Cardiovascular examination was unremarkable.
Her vital signs were stable.
Her medical history was significant for hypertension, for which she was on a single agent
Amlodipine. She also described having a ‘bleed in
the brain’ 4 years ago, from which she made a good
recovery and was living at home with her daughter
providing support for some domestic activities. Her
premorbid modified Rankin score was 2.
Looking through the records a CT head from
4 years ago showed an intraparenchymal haemorrhage in the left temporal and occipital lobe
(figure 1). Subsequent MRI and MR Angiography
failed to establish any underlying aetiology of bleed.
In the emergency department, a CT head was
repeated, which demonstrated an acute intraparenchymal haemorrhage, this time in the right parieto-­
occipital lobes with extension into the lateral and
third ventricle. This also showed high density foci
within the left temporal and occipital lobe, likely
representing parenchymal calcification at the site of
previous haematoma (figure 2).
She was admitted to the stroke ward and over
course of next week, developed insight into her
visual deficit. Her vision improved to some extent
over next 2 weeks, but only to facial and colour
recognition on bedside examination. She was
needing assistance with mobility, personal care and
activities of daily living by the time of discharge.
She was discharged home with support. Her modified Rankin score was 4 on discharge.
Our second case is an 88-­
year-­
old previously
well man. He fell in his garden and subsequently
suffered a fracture of distal part of his right femur.
Prior to this he had been living independently, with
premorbid modified Rankin score of 1. Patient
subsequently underwent an open reduction and
internal fixation of his femur. A week after the
procedure, he was an inpatient undergoing rehabilitation, when he became increasingly confused.
Initial investigation and management of delirium
was focused on electrolyte correction, pain management and search for a possible source of infection.
Patient was also started on empiric antibiotics. A
CT head done at this stage was reported as normal
though neuro-­radiologist documented some suspicion of increased density within the right posterior
cerebral artery (PCA). No associated brain infarction was noted (figure 3). He was reviewed by the
ortho-­geriatric team, who did not find any clear
neurological deficit and hence advised that stroke
was less likely to be the underlying cause of his
delirium. Patient continued to receive prophylactic

Chaudhry FB, et al. BMJ Case Rep 2019;12:e228103. doi:10.1136/bcr-2018-228103

1

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Reminder of important clinical lesson

Figure 1 Old CT head showing left occipito-­temporal haemorrhage.
Figure 3 Hyperdense right posterior cerebral artery.
dalteparin as routine for prevention of venous thromboembolism as an inpatient.
Unfortunately, over the next 36 hours he became increasingly
confused and drowsy. His Glasgow coma scale (GCS) dropped
to 12. CT head was urgently repeated and this time it showed
bilateral occipital lobe infarction, a left temporal lobe parenchymal haemorrhage and infarction of right posterior temporal
lobe. A possible increased density within both PCAs was
reported, suspicious of bilateral PCA infarcts (figure 4). Patient
was transferred to stroke ward. Well established infarcts and an
uncertain time of onset meant acute measures like thrombolysis
and thrombectomy were not appropriate. Over the course of a
few days, patient’s agitation settled but he remained disoriented
in time, place and person. Due to occipital lobe involvement, a
formal visual field assessment by orthoptics team was organised,
which confirmed complete bilateral visual loss. Patient remained
adamant that he could see. Unfortunately, the accompanying
severe cognitive impairment also remained static over coming
weeks and patient, who previously was independent with a
premorbid modified Rankin score of 1 on admission, was now
discharged to a nursing home with postevent modified Rankin
score of 4.

year-­
old type one diabetic with
Our third case is of a 64-­
end stage renal failure. She routinely underwent haemodialysis
three times a week. She lived in a bungalow with her husband,
helped by carers visiting three times a day (premorbid modified
Rankin score 4). She became confused after a dialysis session,
so she was referred to medical admissions. On arrival, she was
hypertensive with a blood pressure of 250/130 on presentation.
Patient was not oriented in time place or person but there was
no other motor or sensory deficit. It came to light on thorough
neurological examination, including visual field assessment by
confrontation method, that she had loss of vision in all fields.
Patient denied any loss of vision and was confabulating. CT head
revealed a hypodensity in the parieto-­occipital lobes bilaterally,
suggesting a possibility of posterior reversible encephalopathy
syndrome (PRES) (figure 5). Other differential was stroke, so
an MRI head and MR cerebral angiogram was attempted but
abandoned mid procedure, as patient was not able to tolerate
it. Patient was managed by lowering blood pressure with

Figure 2 New CT head showing right occipital haemorrhage.

Figure 4 Bilateral posterior cerebral artery infarcts 24 hours later.

2

Chaudhry FB, et al. BMJ Case Rep 2019;12:e228103. doi:10.1136/bcr-2018-228103

BMJ Case Rep: first published as 10.1136/bcr-2018-228103 on 3 December 2019. Downloaded from http://casereports.bmj.com/ on January 9, 2020 at Tulane University Medical Center
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Reminder of important clinical lesson

Figure 7 (A) Prestent and (B) poststent thrombectomy and clot
retrieval from basilar artery.

Figure 5 Bilateral hypodense occipital lobes due to posterior
reversible encephalopathy syndrome.

recovery was made difficult by a large neurological deficit and
recurrent chest infections. Patient was eventually discharged to a
hospice for end of life care.

Outcome and follow-up
intravenous nitrate infusion. Her vision failed to recover. After a
period on the ward, she was discharged to a nursing home.
Our last case is that of an 80-­year-­old woman, brought to
emergency department after a collapse. Husband described
that she was well on waking up. An hour after waking up, she
had symptom of dizziness, and then collapsed. She had medical
history of hypertension and stroke in 2013, from which she made
a good recovery and was now independent with a premorbid
modified Rankin score of 1. On examination her GCS was 6.
She was breathing spontaneously and maintaining oxygen saturation. Her pupils were fixed and dilated, and dolls eye reflex
was absent. After securing airway, CT head and CT cerebral
angiogram were performed that confirmed a thrombotic occlusion of a distal basilar artery (figure 6). As she had presented
within thrombolysis window of 4.5 hours, intravenous alteplase
was administered. Imaging had confirmed a proximal vessel
occlusion, so case was referred to intervention neuro-­radiologist.
Mechanical thrombectomy of basilar artery was performed, with
good visualisation of flow (figure 7). In next 24 hours patient
made little if any recovery and next day CT head revealed bilateral PCA territory infarcts involving the thalami, medial temporal
and occipital lobes infarcts, more extensive on right. We started
post stroke care and nasogastric tube (NG) feeding. Over the
next week patient made a slow recovery and regained consciousness. Detailed assessment at this stage confirmed gross visual loss
in both eyes though patient kept denying this. Unfortunately,

Figure 6 (A) Hyperdense basilar artery (arrow), (B) Filling defect in
basilar artery on CT (arrow).
Chaudhry FB, et al. BMJ Case Rep 2019;12:e228103. doi:10.1136/bcr-2018-228103

All cases with Anton syndrome, had significant deterioration in
functional status. At presentation, all four patients were living at
home. Post event three out of four were institutionalised. Out of
these, one was transferred to hospice for palliation. Discharged
to home of one patient was made possible only with a big support
package. All patients showed a large deterioration in their functional status as measured by modified Rankin scale.

Discussion

Anton-­
Babinski syndrome is a rare neuropsychiatric disorder
characterised by bilateral cortical blindness.1 Its key features are
visual agnosia, anosognosia and confabulation. It stands as one
of the most striking examples of lack of insight.
The first ever description of a blind person, in denial of his
blindness, was not by a clinician but by the French renaissance
writer Michel de Montaigne (1533–1592). In the second book
of his three-­book series ‘Essais’, he mentioned a nobleman who
loses his eye sight without taking a note of it.2 The syndrome is
named after Gabriel Anton (1858–1933), an Austrian Neurologist and Psychiatrist, best known for his descriptions of asomatognosia and visual anosognosia.3
Anton’s syndrome should be considered in all cases of visual
impairment, with bilateral occipital lobe lesions. Underlying
pathology is injury to the visual association cortex in the occipital lobes. The anterior visual pathways remain intact. The most
common cause of cortical blindness is PCA occlusion.4 When the
terminal bifurcation of basilar artery is involved in a thrombo-­
embolic event, resulting stroke can be bilateral.5 This was the
cause in our fourth case.
In the first case described here, two separate events of spontaneous intracerebral haemorrhage, involving each occipital
lobe, first on left and then on right, led to complete blindness.
The most common cause of spontaneous intracerebral haemorrhage is hypertensive vasculopathy.6–8 But in cases of lobar
haemorrhages, cerebral amyloid angiopathy (CAA) should also
be considered as a potential cause,9 10 especially when dealing
with recurrent lobar haemorrhages in a patient above the age
of 55.11 CAA tends to favour areas of brain supplied by posterior circulation, meaning areas perfused by the vertebra-­Basilar
system. Hence, it more commonly affects cerebellum, occipital
and temporal lobes, than the frontal and parietal lobes.12 This
might be due to failure of posterior circulation vessels to eliminate beta amyloid peptide efficiently.13 There are also reported
3

BMJ Case Rep: first published as 10.1136/bcr-2018-228103 on 3 December 2019. Downloaded from http://casereports.bmj.com/ on January 9, 2020 at Tulane University Medical Center
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Reminder of important clinical lesson

cases of bilateral occipital lobe haemorrhages due to PRES
causing sudden onset blindness.14 Interesting feature of the first
case presented here, is that the two haemorrhagic strokes are
4 years apart, favouring CAA.
While Anton syndrome is characterised by visual loss with
visual agnosia and confabulation, cognitive impairment is typically not associated with it.15 PCA supplies the occipital lobe
through the lateral and medial occipital cortical branches. It
also supplies the uncus and anterior part of the fusiform gyrus
(through the Anterior temporal branch) and inferior temporal
gyrus (through the Posterior temporal branch). These parts
control recognition, visual processing, memory and perception.16 17 Damage to these can lead to impairment of executive
functioning and memory.18 As main motor and sensory pathways remain mostly intact, despite damage to an extensive area
of brain, these patients escape without having major motor or
sensory deficits. This can fool clinicians especially when dealing
with elderly patients where causes of confusion can be manifold.
As cerebral infarction may not be visible on CT scan in acute
phase, the initial work up of delirium may not yield a positive
diagnosis. This is true for the second case described here. A thorough clinical assessment, including visual fields by confrontation
can help in cooperative patients. In uncooperative patients or if
suspecting that patient is confabulating, visual threat can be used
to detect if patient can truly see.
Bilateral temporal lobe involvement is a unique pattern with
a limited differential diagnosis.19 Occlusion of the basilar tip
and bilateral posterior cerebral arteries can cause infarction of
both temporo-­occipital regions.19 These patients present with
abrupt onset of confusion, agitation and visual disturbance.
Agitation can settle within days, but visual and cognitive impairment can persist for years.20 Further symptoms can arise when
both thalami are affected. Although presentation of bilateral
thalamic infarct can be visual, sensory or motor,21 the last patient
described, suffered from increased somnolence and drowsiness.
These features have been described with thalamic lesions. The
proposed mechanism is disruption of the activating impulses
from brainstem reticular formation.22
As mentioned above, PRES is also known to involve bilateral
occipital and parietal lobes. Other than visual loss, it can present
with headache, confusion and seizures. It has been described
with sudden rise in blood pressure in cases of renal failure.23 By
definition, PRES should be reversible and neurological deficit
should improve on lowering the blood pressure.24 Although
delay in diagnosis can lead to permanent neurological deficit,
which may have been the case with our third patient described
here. This could be due to secondary processes than can occur
with PRES like focal cerebral vasospasm causing infarction or

Learning points
►► In the time of face, arm and speech test assessment, clinicians

can miss important aspects of a cerebrovascular disease,
especially in a confused elderly patient, often leading to
misdiagnosis.
►► Extensive brain damage, especially in posterior circulation
territory, giving deficits like visual defects and cognitive
impairment, can be missed on initial assessment if clinicians
are not vigilant.
►► Visual and cognitive impairment can have both short-­term
and long-­term implications on rehabilitation and prognosis.

4

haemorrhage. In appropriate cases, MRI can be helpful in differentiating stroke from PRES. PRES will present with hyperintense
signals on T2 and fluid attenuation iversion recovery (FLAIR)
sequences of MRI, while it will not restrict on diffusion weighted
sequence, which is a feature, typical of infarction.25
Contributors FBC was involved in care of these patients and contributed in writing
up the case report and discussion. SR helped in review of literature and with her
vast experience in radiology, helped in image selection. UA contributed to literature
review, writing abstract and discussion.
Funding The authors have not declared a specific grant for this research from any
funding agency in the public, commercial or not-­for-­profit sectors.
Competing interests None declared.
Patient consent for publication Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.

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Chaudhry FB, et al. BMJ Case Rep 2019;12:e228103. doi:10.1136/bcr-2018-228103

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Reminder of important clinical lesson

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Reminder of important clinical lesson