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Intracranial arachnoid cysts presenting with first-episode mania and subsequent hyperammonemic encephalopathy: A case report

 Department of Psychiatry, SRIHER, Chennai, Tamil Nadu, India

Date of Submission05-Aug-2021
Date of Decision30-Aug-2021
Date of Acceptance22-Sep-2021
Date of Web Publication15-Mar-2022

Correspondence Address:
Suvarna Jyothi Kantipudi,
SRIHER, Chennai, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aip.aip_101_21


Intracranial arachnoid cysts are often an incidental discovery in the course of neuroimaging for other conditions. While often asymptomatic, cysts which enlarge can cause mass or pressure effects on adjacent structures. We report a 33-year-old male patient who presented with first episode of manic symptoms. Following treatment with sodium valproate patient developed altered sensorium and was subsequently diagnosed with middle cranial fossa arachnoid cysts and valproic acid-induced hyperammonemic encephalopathy that was successfully treated with enteric lactulose. There are several case reports of arachnoid cysts presenting in patients with psychiatric disorders and debating whether these cysts are a cause or co-occurrence. In 16 reported patients, who had arachnoid cysts with psychiatric symptoms, 9 had cysts exerting mass/pressure effects. Three patients had surgical intervention and showed significant improvement following surgery. So did 1 patient who was treated with mannitol infusion. Intracranial arachnoid cysts may also present with atypical psychiatric symptoms or complicate the treatment process by way of poor response or treatment emergent adverse effects. There is an important role for thorough neurological examination, neuroimaging, and vigilant use of psychotropics in such patients.

Keywords: Arachnoid cysts, mania, psychiatric symptoms, valproic acid-induced hyperammonemic encephalopathy

How to cite this URL:
Kantipudi SJ, Suresh N. Intracranial arachnoid cysts presenting with first-episode mania and subsequent hyperammonemic encephalopathy: A case report. Ann Indian Psychiatry [Epub ahead of print] [cited 2023 Mar 22]. Available from: https://www.anip.co.in/preprintarticle.asp?id=339658

  Introduction Top

Arachnoid cysts are benign, extra-axial, cystic lesions formed due to congenital splitting of the arachnoid layer.[1] They are often discovered incidentally, either by fetal cranial ultrasound or as an asymptomatic finding on neuroimaging studies in adulthood.[1] We report a case of a patient with middle cranial fossa arachnoid cysts presenting with mania with psychotic symptoms who had a complicated course of recovery and also present a review of literature on the psychiatric manifestations of arachnoid cysts to better characterize their clinical presentation, diagnosis, and treatment.

  Case Presentation Top

A 33-year-old single male, with no significant past medical or psychiatric history, was brought by his family members with a history of increased religiosity, decreased need for sleep, increased cheerfulness, and racing thoughts since 7 days, increased talk since 3–4 days and grandiose claims, abusive language and disinhibited behavior since the previous day. He had no h/o substance use or any prior psychiatric disorder. Premorbidly, the patient was reported to be well-adjusted. There was family history of prescription medication abuse and psychiatric disorder in maternal uncle, further details were however not available. Physical examination was normal and there were no focal neurological deficits. During mental status examination, the patient was observed to be restless and had verbose speech, irritable, and elevated mood and delusions of grandiosity. No perceptual abnormalities were elicited. He was admitted as an in-patient for evaluation and management. The timeline of events post admission were detailed in [Table 1].
Table 1: Timeline of events after the patient was admitted to the psychiatry ward

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Diagnostic assessment and therapeutic intervention

Young Mania Rating Scale done at the time of admission yielded a score of 21 suggestive of mania. Baseline blood investigations were done. Complete blood count, random blood sugar, liver, and renal parameters, thyroid function test were all within normal limits. Electrocardiogram was also normal. Patient was given injection haloperidol 10 mg intramuscular (IM) stat, injection promethazine 50 mg IM stat and started on tablet sodium valproate 500 mg hsod along with tablet clonazepam 0.5 mg hsod. Patient's agitation and restlessness subsided the day after admission and over the next 2 days he was seen to be less irritable and talkative, and sleeping better. On 4th day after admission, the patient developed drowsiness and decreased responsiveness with one episode of urinary incontinence. On examination Glasgow Coma Scale was E-2, V-3, M-4 - total 9/15, bilateral pupils 5 mm equally reacting to light. In view of altered mental status, repeat electrolytes, serum calcium, magnesium, and serum ammonia were done. All were within normal limits except serum ammonia which was 262.8 mcg/dL. As liver function test (LFT) was normal, he was diagnosed with valproic acid induced hyperammonemic encephalopathy. Urgent computed tomography brain plain was also done which revealed extra-axial arachnoid cystic lesions measuring 4.5 cm × 3.8 cm × 3.1 cm and 3.6 cm × 2.8 cm × 3.0 cm noted in middle cranial fossa in the bilateral anterior temporal region and bilateral anterior temporal lobes appeared mildly hypoplastic and displaced posteriorly [Figure 1]. All psychiatric medications were withheld; the patient was supportively managed with intravenous fluids and syrup lactulose 30 ml 6th hourly, lactulose enema BD and planned for electroencephalography (EEG). However, the patient was discharged at request by attenders due to logistic reasons and taken to a government hospital where EEG done was found to be normal. Electrophysiology study was normal. Repeat LFT was also found to be normal.
Figure 1: Well-defined cystic lesion of cerebrospinal fluid density in bilateral anterion temporal region with atrophy of adjacent temporal lobes

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Follow-up and outcome

Subsequent to treatment with enteric lactulose and normalization of serum ammonia levels, the patient was reported to have regained normal mental status and responsiveness and also developed spontaneous remission of psychiatric symptoms despite not restarting psychotropics. At 1-month telephone call follow-up, the patient was reported to be remaining asymptomatic and doing well.

  Discussion Top

There have been several case reports in the past elucidating the discovery of arachnoid cysts in patients with psychiatric disorders and discussing the role of these cysts in psychiatric manifestations, however, there is no hard and fast evidence to prove that arachnoid cysts by themselves cause psychiatric disorders. During a Google Scholar and PubMed search in May 2018, 12 full-text articles were identified which fulfilled eligibility criteria reporting on a total of 16 patients [Table 2].[2],[3],[4],[5],[6],[7],[8],[9],[10],[11],[12],[13] All were case reports on individual patients except one article, which reported on two cases and one which was a case series of 4 patients. In the case reports, we reviewed only 3 out of 16 patients were female. Age at presentation ranged from 18 to 57 years with more patients in the third and fourth decades. Only 4 out of 16 patients had onset of symptoms recently with current visit being their first visit to psychiatrist. In 2 out of 16 patients, headache was the reason for imaging, in 1 patient, imaging was done due to abnormal EEG, in all others, imaging seemed to have been done during routine course of investigations and reason was not specified. All of the patients had psychotic illness predominantly auditory hallucinations and delusions. The arachnoid cysts most commonly were noted in the middle canial fossa, (10 out of 16 patients) followed by posterior cranial fossa. In 9 out of 16 patients, the cysts exerted mass/pressure effects. Surgical procedures were resorted to in 3 out of 16 patients, all of whom showed significant improvement in psychiatric symptoms following surgery. One patient was treated with mannitol infusion as anti-edema measure who also showed significant improvement. All other patients were managed with anti-psychotics with varying degrees of improvement. Risperidone was the most commonly used anti-psychotic that was used in 6 out of 16 patients. In the case reports we reviewed, all the patients in whom surgical interventions or anti-edema measures were necessitated showed significant improvement of psychiatric symptoms indicating the organic etiology of these symptoms. In contrast, the patients treated with antipsychotics only showed varying degrees of improvement. Thus, while the origin of such psychiatric disorders is likely multifactorial, in those with larger arachnoid cysts causing mass or pressure effects on the cranial lobes, the psychiatric symptoms are mostly due to the organicity of the cysts. The patient discussed in our case report also had middle cranial fossa arachnoid cysts displacing bilateral anterior temporal regions posteriorly which may have contributed to his manic symptoms. Our patient subsequently developed valproate-induced hyperammonemic encephalopathy secondary to treatment and recovered following treatment with enteric lactulose, also developing spontaneous remission of psychiatric symptoms. It is notable that adverse side effects are more common with patients who have preexisting intracranial lesions, and such patients needed to be treated with extra caution and judicious use of psychotropics. Hence, we suggest careful neurological examination and imaging wherever feasible in psychiatric patients who have previously not been screened, particularly those with atypical features, complicated course or poor response to treatment.
Table 2: Characteristics, presentation, treatment and outcome of psychiatric symptoms in patients with intracranial arachnoid cysts

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Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published, and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Logan C, Asadi H, Kok HK, Looby S, O'Hare A, Thornton J, et al. Arachnoid cysts-common and uncommon clinical presentations and radiological features. J Neuroimaging Psychiatry Neurol 2016;1:79-84.  Back to cited text no. 1
Bahk WM, Pae CU, Chae JH, Jun TY, Kim KS. A case of brief psychosis associated with an arachnoid cyst. Psychiatry Clin Neurosci 2002;56:203-5.  Back to cited text no. 2
Da Silva JA, Alves A, Talina M, Carreiro S, Guimarães J, Xavier M. Arachnoid cyst in a patient with psychosis: Case report. Ann Gen Psychiatry 2007;6:16.  Back to cited text no. 3
Vakis AF, Koutentakis DI, Karabetsos DA, Kalostos GN. Psychosis-like syndrome associated with intermittent intracranial hypertension caused by a large arachnoid cyst of the left temporal lobe. Br J Neurosurg 2006;20:156-9.  Back to cited text no. 4
Ahmed SE, Khan AH. Acetazolamide: Treatment of psychogenic polydipsia. Cureus 2017;9:e1553.  Back to cited text no. 5
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[PUBMED]  [Full text]  
Mironov A, John S, Auerbach J, Jamaleddine G. Acute onset of psychosis in a patient with a left temporal lobe arachnoid cyst. Case Rep Med 2014;2014:204025.  Back to cited text no. 7
Baquero GA, Molero P, Pla J, Ortuño F. A schizophrenia-like psychotic disorder secondary to an arachnoid cyst remitted with neurosurgical treatment of the cyst. Open Neuroimag J 2014;8:1-4.  Back to cited text no. 8
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Maner F, Babalioglu M, Cetinkaya O, Ipekcioglu D, Ergen N, Yesil R, et al. The coexistence of arachnoid cyst with first episode psychosis: Four cases. J Neurol Disord 2014;2:186.  Back to cited text no. 12
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  [Figure 1]

  [Table 1], [Table 2]


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