Abstract

A cavum Septum Pellucidum is a cerebrospinal fluid-filled (CSF) cavity between the lateral ventricles and is considered a normal anatomic variant sporadically seen on neuroimaging. While a cavum septum pellucidum is a relatively uncommon incidental neuro- imaging finding, symptomatic cysts of the cavum septum pellucidum are very rare, with only a few cases reported in the literature so far. This study comprises of 6 patients 1 female and 5 males, age ranging from 1-70 years old treated at 2 clinics between 2021-2024 who were being managed by an ongoing process of monitoring through follow-ups and medical measures. These cases would guide future diagnosticians who come across this pathology in patients with limited resources and reluctance for non-pharmacological interventions since it can be difficult to treat something with very little evidenced literature.

Keywords: Cavum septum pellucidum cyst, imaging, Hydrocephalus, intervention, symptomatic.

INTRODUCTION

The cavum septum pellucidum is defined as a normal cavity present during the growth of a fetus, its embryological origin takes place when two leaflets of the septum pellucidum are formed which contains a cerebrospinal fluid (CSF) filled cavity in between them, in 85% of cases the leaflets fuse by three to six months postnatally in a caudal to rostral direction ending the existence of this structure but in a rare occurrence it might persist even after that. It is present in as much as 12% of children between 6 months and 16 years [1-3]. Other than the congenital persistence of CSP it has also been reported as an acquired cause after repetitive trauma as seen in professional contact sport athletes such as retired boxers and American football players [4, 5].

Previously the CSP was also known as the fifth ventricle but that term was labelled inappropriate as it is deprived of its choroid plexus and is non-continuous with the rest of the ventricular system [6]. It is most commonly observed as an innocuous incidental finding on an MRI and in some uncommon cases, the persistence of this cavity may lead to the formation of an expanded Cyst which could be labeled as asymptomatic or symptomatic depending on the presentation [3]. The proper criteria for these cysts are still ill-defined but multiple authors state that it can be characterized by lateral bowing of the walls with membrane distance at least 10mm or more with the main symptomatic presentation being headaches, nausea or vomiting, loss of consciousness, and psychiatric disturbances. A cyst large enough can also produce neurological impairment by compression

of the neighboring neural structures with the patient presenting with specific symptoms such as seizures, visual disturbances, gait changes, vertigo, and cognitive impairment [4, 7, 8].

This study aims to highlight the array of Cavum Septum Pellucidum Cyst cases we have encountered, managed and followed up with and compare it with the previously available literature to add a new insight to its treatment.

CASE DESCRIPTION

CASE 1

We present the case of a 20-year-old male who had his first episode of generalized tonic-clonic fits five years prior in 2018 and was treated at the emergency department of a secondary care hospital. The fits were treated with intravenous diazepam. During the presentation to our clinic, the patient had no active complaints. His physical examination was unremarkable, and there were no focal neurologic deficits. The results of additional laboratory tests were negative, which aided in ruling out differentials. The patient was born through normal vaginal delivery and had no history of obstructive or traumatic birth. He denied the use of any recreational drugs or a history of traumatic injuries to the head. In 2020, he presented to the emergency department with generalized tonic-clonic seizures. After symptomatic management an MRI with and without contrast Gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA) was performed, which showed a cavum septum pellucidum cyst measuring 17mm by 22mm as well as cavum vergae were also visualized (Fig. 1). Later on, the patient reported his third episode of tonic clonus seizures in 2022, he was then prescribed oral sodium valproate (500mg) twice daily, with which he has been compliant to date. The patient has been asymptomatic ever since, and he

has not reported any new episodes of seizures, on telemedical inquiry he is now able to perform his daily activities including his job without any problem, he does experience episodes of slight headache once a week but according to him, it is manageable. Now it has been more than a year, and he is still on Sodium Valproate 500mg once daily just before bed.

CASE 2

A 13-month-old female presented with 2 episodes of seizures. Physical Examination did not reveal any findings. An MRI of the head with and without contrast (Gd-DTPA) was performed and we came across a CSP cyst (Fig. 2) the patient was treated symptomatically and was given anti-epileptic levetiracetam dosed according to her body weight, and her symptoms subsided and she did not report any future complications or recurrence on follow-up after 3 months.

CASE 3

A 16-year-old male patient presented with only symptoms of gradual continuous headache, Examination was

unremarkable for any focal neurological deficits we performed an MRI, and an incidental Cavum septum pellucidum cyst was observed with posterior extension, cavum vergae along with concomitant communicating hydrocephalus (Fig. 3) which we believed to be the cause of his headaches. Ventricular diversion procedure was advised at that time with proper risk-benefit counseling, along with symptomatic treatment for headaches. However, the patient was lost on follow-up.

CASE 4

A 4-year-old male patient presented with headache, difficulty in walking, and signs of raised intracranial pressure (papilledema was evident through fundoscopy). There was a birth history of cesarean section along with vascular insult and hypoxia. The patient had an MRI scan done beforehand and after having a look at his imaging