Dear Editor,
Shunt overdrainage is seen in 10%–12% of patients with ventriculoperitoneal (VP) shunts, and it may manifest as intracranial hypotension syndrome characterized by orthostatic headache, vomiting, and/or cranial nerve deficits. However, in the rare scenario, it can present with rapid cognitive decline with behavioral issues of the frontotemporal dementia phenotype. This is important to identify in the appropriate clinical circumstance as this is a reversible cause of cognitive impairment. Here we describe a middle-aged female who presented with a rapidly progressive cognitive decline with a background history of craniopharyngioma treated with partial resection and bilateral VP shunting. A 42-year-old woman with no comorbid illnesses presented with a 12-month history of behavioral and personality disturbances in the form of intermittent aggressiveness, lack of interest in her surroundings, and reduced interaction with people. She also had reduced attention and concentration, along with memory decline. She had social disinhibition in the form of changing her clothes in front of family members and urinating in inappropriate places. She also had difficulty in naming objects, identifying faces, and had navigational difficulties inside her house and outside. She had no insight, ignored personal hygiene, and was dependent on her son for all her activities of daily living. She did not have any headache, gait imbalance, cranial nerve deficits, or vomiting associated with these symptoms. Four years back, when she presented with new-onset holocranial headaches and vomiting for about a month duration, she was detected to have a suprasellar lesion with obstructive hydrocephalus on a computed tomography (CT) scan. [Figures 1a-c]. We did a right ventriculoperitoneal shunting (Surgiwear ™, Medium Pressure) [Figure 2a]. Since the left lateral ventricle started enlarging symptomatically four months later, we also had to place another similar shunt on that side [Figure 2b]. We then performed a deliberate subtotal excision (to avoid unacceptable deficits) of the suprasellar craniopharyngioma, ascending into the third ventricle, using a minifrontal sub-frontal approach after another year. Then, she was treated with external beam radiotherapy to control the residual tumor. At that time, she had no gross behavioural or memory disturbances. However, she had bitemporal hemianopia due to the craniopharyngioma compressing on the optic apparatus before the decompression, which persisted after surgery. She continued replacement doses of prednisolone and thyroxine after the surgery for hypopituitarism.
Figure 1.
(a) NCCT head showing hydrocephalus; (b) Hyperdense suprasellar mass causing obstructive hydrocephalus (c) Lesion shows peripheral coarse calcification. NCCT: Non-contrast computed tomography
Figure 2.
(a) NCCT head showing obstructive hydrocephalus with right ventriculoperitoneal shunt; (b) Resolution of hydrocephalus after placing bilateral VP shunts. NCCT: Non-contrast computed tomography, VP: ventriculoperitoneal
During the current presentation, she was conscious, but not oriented to time, place, or person. General physical examination was unremarkable. She had poor attention with lack of insight; the Mini Mental Status Examination (MMSE) and detailed lobar functions could not be completely assessed. Cranial nerve examination revealed bitemporal visual field deficit by confrontation test. Fundus examination did not show papilledema, and other cranial nerves were normal. Motor, sensory, gait, and cerebellar system examination was unremarkable. There was activated rigidity involving both upper limbs with frontal release reflexes.
Routine blood investigations were within normal limits, including thyroid, liver, and kidney functions, vitamin B12, and serum Venereal Disease Research Laboratory. Viral markers comprising human immunodeficiency virus, hepatitis B surface antigen, and anti-hepatitis C virus antibodies were negative. Brain MRI with contrast showed residual craniopharyngioma with bilateral VP shunts in situ, along with pachymeningeal enhancement along bilateral frontal convexity and slit-like collapsed ventricles, suggestive of intracranial hypotension [Figures 3 and 4].
Figure 3.
(a) Post right frontal mini-craniotomy status-axial MRI brain FLAIR sequence showing a multiloculated solid cystic suprasellar mass with septations with compression of surrounding structures; (b and c) Axial FLAIR MRI brain showing collapsed slit like ventricles - bilateral VP shunts in situ. MRI: Magnetic resonance imaging, FLAIR: Fluid-attenuated inversion recovery, VP: ventriculoperitoneal
Figure 4.
(a) Axial FLAIR MRI brain showing collapsed slit-like ventricles and bilateral caudate hyperintensities; (b) Coronal T2 weighted image showing bilateral caudate infarcts; (c) Axial T1 contrast MRI showing intense pachymeningeal enhancement; (d) Coronal T1 MRI showing pachymeningeal enhancement. MRI: Magnetic resonance imaging, FLAIR: Fluid-attenuated inversion recovery
A lumbar puncture showed an opening pressure of only 2cm H2O, with no cells and normal glucose and protein, consistent with intracranial hypotension. Cerebrospinal fluid (CSF) malignant cytology was negative. She underwent bilateral VP shunt ligation surgery for shunt overdrainage, after which she started showing a remarkable and steady improvement in cognitive decline from the third day. She became more oriented and attentive, was able to identify her relative’s faces, and had improvement in her apathy. She also was able to communicate well with the relatives. Neuropsychology assessment showed an MMSE score of 18/30 and Montreal Cognitive Assessment Scale (MoCA) of 12/30, but she had executive dysfunction, constructional apraxia, reduced word fluency, and impaired new learning ability. Serial head CTs after the shunt ligation revealed no hydrocephalus, and she had no symptoms of raised intracranial tension. At 1 month follow-up, she had no significant personality or behavioral abnormalities, and her memory complaints also had subsided to a significant extent. The MMSE and MoCA at 1 month follow-up were 20/30 and 14/30, respectively.
Intracranial hypotension syndrome is a rare phenomenon of multiple causes and variable manifestations. It can occur spontaneously due to shunt over drainage, after rupture of an arachnoid cyst, or after cerebrospinal fluid leaks after lumbar puncture, trauma, or cranial/spinal surgery. Usually, patients present with orthostatic headaches, neck pain, cranial nerve abnormalities, or movement disorders.[1,2]
Shunt overdrainage usually occurs in 10%–12% of patients, and may present as intracranial hypotension syndrome, slit ventricle syndrome, subdural fluid collection, or tonsillar herniation.[3,4] Usually, the triad comprises postural headache, low CSF opening pressure, and uniform enhancement of meninges.[5] This complication is usually reported 5–15 years after shunt placement, but in our patient, it occurred within 3 years of VP shunting. Even though orthostatic headache is the most common feature, our patient lacked this complaint. Cognitive impairment, predominantly of the behavioral variant frontotemporal dementia (FTD) type, a rare complication, referred to as the brain sagging dementia, was noted in our patient. Wicklund et al.[6] reported eight patients with frontotemporal brain sagging syndrome, whose median age of symptom onset was 53 years, and all of them had slowly progressive behavioral and cognitive impairment associated with headache. Brain MRI showed evidence of brain sagging in all of them with brainstem distortion, with three cases having diffuse enhancement of the pachymeninges. A definitive CSF leak site was not identified by myelography in any of them.
The mechanism behind the cognitive impairment is the intracranial pressure reduction causing the brain to sag toward the base of the skull, resulting in mechanical disruption of ventromedial and brainstem structures with associated frontotemporal network dysfunction.[6] The MRI features of uniform pachymeningeal enhancement and slit-like ventricles were present in our patient, similar to the previously reported cases.[6,7,8,9] Our patient, in addition, had progressive bilateral caudate infarcts that started appearing four months after completing radiotherapy, initially on the left side and later as a lacunar infarct on the right side as well; these infarcts were likely the result of radiotherapy-induced perforating artery damage [Figure 4].[10]
Usually, most cases of intracranial hypotension resolve with conservative management. The common surgical approach is shunt revision, which aims to establish the shunt patency and minimizes CSF overdrainage by changing the valve system with a higher resistance valve or a programmable valve, with success rates reported from 30% to 100%.[11] The behavioral abnormalities and cognitive impairment in our patient responded significantly to shunt ligation. We ligated the shunt since imaging showed that the subtotal decompression had removed the obstruction at the two foramina of Monroe, and there was a good chance that the natural CSF flow pathways had been re-established.
Intracranial hypotension syndrome can present without orthostatic headaches and can manifest like the behavioral variant frontotemporal dementia phenotype. It is important to identify intracranial hypotension syndrome in the appropriate context as it is a rapidly reversible cause of dementia.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initials will not be published and due efforts will be made to conceal her identity, but anonymity cannot be guaranteed.
Conflicts of interest
There are no conflicts of interest.
Acknowledgements
The authors thank the patient and her family for their cooperation.
Funding Statement
Nil.
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