Cavum septum pellucidum in a case of schizophrenia presenting with self-mutilating behavior.

Cavum septum pellucidum (CSP) is a neurodevelopmental anomaly, which is commonly reported in schizophrenia patients. Various symptoms of schizophrenia, including thought disturbances have been associated with CSP. We present a rare case of undifferentiated schizophrenia with CSP who presented with self-mutilating behaviors.

Cavum septum pellucidum (CSP) is a neurodevelopmental anomaly characterized by the presence of a thin plate of two laminae, which forms the medial wall of the lateral ventricles that fails to fuse forming a fluid filled cavity.[1] The enlarged CSP, which persists postnatally is considered to be a putative marker of disturbances in early brain development.[2] Previous studies have also shown an association of CSP with severe thought disturbances, more negative symptoms, higher suicide rates and greater cognitive deficits in schizophrenia.[3] We present a case of undifferentiated schizophrenia, who presented with self-mutilating behavior, was found to be having CSP.

CASE REPORT

A 28-year-old unmarried male from low socioeconomic status came to the hospital for consultation of psychiatric problems along with his caregivers. There was no past psychiatric or medical history or family history of mental illness. The presenting complaints were unprovoked aggressive outbursts, poor self-care, disorganized behavior and self-mutilating behaviors for last 4 years. Physical examination revealed old burnt scar over the forehead, fused ear lobules bilaterally and polydactyly in right upper limb and crush injury of left thumb and index finger. On mental status examination, patient was unkempt, disheveled with poor eye contact. He was irritable and guarded. No thought and the perceptual abnormality were elicited at the time of admission. He was diagnosed as “undifferentiated schizophrenia” according to International Classification of Disease-10th version.[4]

Patient was advised to take in-patient psychiatric care on the same day of consultation. He remained aggressive, disorganized and on two occasions, he tried to crush his left index finger and thumb by hammering it with a stone. He was started on electro convulsive therapy (ECT) sessions considering aggressive outburst and self-mutilating behavior. During pre-ECT evaluation “computed tomography” scan of the head revealed “Grade II CSP” [Refer Figure 1]. Along with ECT, patient also received oral chlorpromazine 600 mg/day, which was hiked gradually over 2 weeks.

Figure 1

Plain computed tomography image of the patient and arrow head pointing towards cavum septum pellucidum

Patient started showing improvement in aggressive and self-mutilating behavior. On mental status examination, he reported that he became angry for no apparent reason, following which he would start hammering his fingers with stones. He also reported delusion of persecution against parents. He received nine sessions of ECT with minimal cognitive impairment and was continued on oral chlorpromazine 600 mg/day without any side effects. There was improvement in self-mutilating behavior, disorganized behavior and poor self-care, but occasional aggressive outbursts persisted. He was discharged on chlorpromazine 600 mg/day.

DISCUSSION

Anatomically, the septum pellucidum consists of two laminae of tissue composed of white matter surrounded by gray matter. The septum is known to be a part of the limbic system and is connected via the medial forebrain bundle to the hypothalamus and via the fornix to the hippocampus and amygdala.[5] CSP is present in 100% of fetuses and premature infants, but the posterior half of the leaves normally fuse by 3–6 months of age.[6] The presence of a CSP later in life reflects neurodevelopmental abnormalities of structures bordering the septum pellucidum, such as the corpus callosum and hippocampus and may be considered as a marker of limbic system dysgenesis.[7]

Despite being a normal variant, CSP has been seen in various psychiatric disorders, most commonly in schizophrenia.[3] In a recent meta-analysis, Trzesniak et al.[3] have mentioned that incidence of CSP ranges between 1.1% and 89.7% in healthy volunteers, and from 10.0% to 89.5% in patients with schizophrenia spectrum disorder. They have also suggested that the clinical significance of CSP may depend more on its size rather than presence or absence in schizophrenia.[3] Nevertheless, one recent longitudinal study has also found that CSP may not be linked to the neurobiology of emerging psychotic disorders and may be related to the progression of the disorder per se.[8]

The exact function of the septum is not yet completely understood; however it may appear to moderate behaviors such as rage and arousal.[9] Interestingly, CSP is associated with aggressive features of antisocial personality disorder compared to nonaggressive ones, indicating particular relevance of septal disruption to aggression in human.[10] Researchers have also found that CSP influences neighboring dense synaptic networks[11] and cause irregularities in the distribution of serotonin (5-HT2A) receptors that may affect the septal regulatory role in the limbic system.[12] In addition, improvement of severe self-mutilation has been reported after limbic leucotomy.[13]

Based on these studies, we hypothesize that limbic dysgenesis may be the reason for aggressive and self-mutilating behavior in our patient. Psychodynamically, self-mutilating behaviors have been termed as “auto aggression.”[14] Self-mutilation has an aggressive element, wherein the person, through self-mutilation directs anger inward which enables him or her to feel in control.[15]

Though several line of management have been proposed including clozapine, lithium, and naltrexone and so on,[16] we preferred ECT and chlorpromazine as there have been previous successful treatment of self-mutilating behaviors with ECT[16] and we chose chlorpromazine considering its sedating property which also reduce psychotic aggression.[17]

In our patient, self-mutilating behavior was not secondary to any psychotic process or any affective disturbance; neither it was explainable from mental status examination. It may be argued that CSP, which has been found to be associated with aggression in a different patient population, also might play a role in self-mutilating behavior in our patient with schizophrenia.

CONCLUSION

We conclude that the self-mutilating behavior in our patient may be an aggressive behavior directed towards self and might be neurobiologically linked to CSP and its relationship with limbic system dysgenesis.