Normal pressure hydrocephalus disguising psychosis: a case report

Normal pressure hydrocephalus (NPH) is a chronic abnormal accumulation of cerebrospinal fluid in the cerebral ventricles without increased intracranial pressure. It can be idiopathic or secondary to haemorrhage, tumour or trauma. The resultant dilatation of the ventricles impairs perfusion in the ventricular walls and generates hypoperfusional states in the frontal lobes, basal ganglia, and thalamus.¹ NPH usually manifests with a classic triad of gait disturbances, cognitive impairment, and urinary incontinence. However, only 52% of patients have all three symptoms at the time of diagnosis.² Psychiatric symptoms can occur in the early course of NPH and may delay the diagnosis.³ Common psychiatric presentations include depression, personality changes, mania, apathy, and akinetic mutism.⁴ In older adults, psychotic symptoms secondary to NPH may be treated as dementia or late-onset schizophrenia. Here, we describe a 60-year-old woman with NPH who had psychotic symptoms as the primary clinical presentation. The various psychotic symptoms secondary to NPH reported in the literature are also reviewed.

In September 2023, a 60-year-old married woman residing in a rural area presented with a 3-year history of undue suspiciousness, muttering and gesticulating to herself, and declining self-care. The symptoms were insidious in onset, continuous, and gradually progressive, with no identifiable predisposing or precipitating factors. The patient strongly believed that people were trying to kill her son and his children. She would validate her claims by saying that she could hear them talking to her and would abuse her neighbours for no reason when they visited her. Whenever family members denied her allegations, she would become irritable and angry. She would remain alert and fearful and would not sleep at nights. In addition, she had occasional incontinence of urine and her fluid intake was significantly reduced. Subsequently, she started to exhibit a broad-based, small-stepped, stooping gait as if she would fall on the ground. This would resolve spontaneously and then recur a few days later, following a periodic, fluctuating pattern. She had no history of persistently low or elevated mood, repetitive thoughts or actions, anxiety, forgetfulness, seizure, substance abuse, or suicidal ideation.

She had visited multiple psychiatrists and was diagnosed with unspecified psychosis. At various points, she had been prescribed quetiapine 600 mg/day, haloperidol 10 mg/day, and valproate 1000 mg/day, but had no significant improvement. Consequently, she stopped taking the medications herself after 2 years. Six months after stopping psychotropic treatment, she presented to us with aggravation of the psychotic symptoms. Family members reported a gradual decline in her domestic activities, self- care, and usual areas of interest.

General physical examination did not reveal any abnormality. Respiratory, cardiovascular, and abdominal examination results were normal. The patient was conscious, alert, and oriented to time, place, and person. Bilateral sensory, cranial nerve, and fundus examination results were normal. On motor examination, muscular bulk, power, and tone and deep tendon reflexes were normal, as were the plantar and superficial reflexes. No signs of meningeal irritation were present. The patient walked slowly with a broad-based, small-stepped, stooping gait.

On mental status examination, the patient was cooperative and her appearance showed appropriate grooming and personal hygiene. Her speech was relevant, coherent, and goal-directed with a suspicious mood, blunted affect, paranoid delusions, and third-person auditory hallucinations. Higher cognitive function was not severely impaired. The patient had no insight into her illness. She was extensively evaluated to rule out all possible causes of organic psychosis. Results of routine blood tests were normal. Test results for syphilis and HIV were negative. Her Mini-Mental State Examination score was 22, indicating mild cognitive impairment. Considering the previous antipsychotic trials, the patient was started on risperidone 2 mg/day, which was increased gradually up to 6 mg/day, but there was no significant improvement in her psychotic symptoms after 2 months.

Magnetic resonance imaging of the brain showed disproportionate dilatation of the lateral ventricles with respect to sulcal spaces, a narrow callosal angle of [lesser than]70°, and a prominent sylvian fissure (Figure). The Evans index was 0.45, suggestive of NPH. Magnetic resonance imaging of the spine was unremarkable.

A high-volume lumbar tap test was performed after consultation with a neurosurgeon. Subsequently, the patient's gait disturbance improved; this confirmed the diagnosis of NPH. Following a standard ventriculoperitoneal shunt procedure, the patient's gait disturbances and psychotic symptoms continued to improve over the following month. Despite a reduction in the frequency of urinary incontinence, this symptom persisted at 1-month follow-up. Risperidone was gradually tapered and eventually discontinued. Although the patient had not experienced active delusions and hallucinations, her interactions with family members remained limited.

NPH may present with varying neuropsychiatric symptomatology that is possibly related to alterations in neurotransmitter activity.⁵ It can cause personality changes, anxiety, depression, psychotic syndromes such as delusion, Othello syndrome, hallucinations, aggressive behaviour, obsessive compulsive disorder, and mania.^6,7 Patients with NPH are three times more likely to have schizophrenia, compared with the general population.³ Most patients with NPH present with the classical triad of gait disturbance, urinary incontinence, and dementia. Psychiatric symptoms usually develop after the appearance of the classical symptoms.² However, cognitive impairment may not be obvious at the time of presentation or may be fluctuating. In such cases, dementia symptoms can occur later, and the psychiatric symptoms may be the presenting picture.

In our patient, the predominant clinical presentation was paranoid psychotic symptoms without any obvious neurological signs. Initially, the peculiar gait was considered a part of psychotic symptoms because it was not persistent. However, the presence of psychosis with incontinence and cognitive decline prompted neuroimaging, which was suggestive of NPH. This disease course is rare, and the paranoid psychosis may have been an organically determined consequence of NPH, as it did not resolve following conventional antipsychotic treatment. In such patients, diagnosis could be delayed, which may impact treatment response and the overall prognosis. Although the incidence of NPH is low, its significance must not be overlooked as a reversible cause of dementia. The range of neuropsychiatric presentations in NPH appears to be broader than that originally described; NPH must be considered whenever there is presentation of psychotic symptoms.⁸

We reviewed the literature on reports of psychosis in NPH (Table).^3,4,6,8-11 The potential atypical presentations of NPH necessitates detailed evaluation, particularly in patients with predominant psychotic symptoms in association with soft non-localising neurological signs and mild cognitive deficits. Early diagnosis and appropriate surgical intervention can lead to significant improvement in symptoms and quality of life. High clinical suspicion of NPH is needed in cases of late-onset psychosis or presenile dementia. Neuroimaging is a valuable, non-invasive modality for establishing the diagnosis of NPH and excluding other organic aetiologies.

Both authors designed the study, acquired the data, analysed the data, drafted the manuscript, and critically revised the manuscript for important intellectual content. Both authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

Both authors have disclosed no conflicts of interest.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

All data generated or analysed during the present study are available from the corresponding author on reasonable request.

The patient was treated in accordance with the tenets of the Declaration of Helsinki. The patient provided written informed consent for all treatments and procedures and for publication.

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