Kluver-Bucy Syndrome (KBS)

Kluver-Bucy Syndrome (KBS) is a neuropsychiatric syndrome caused by lesions of the bilateral temporal lobes, in particular with lesion of the hippocampus and amygdala. KBS is characterized by hyperorality, sexual hyperactivity, changes in dietary behavior, hypermetamorphosis, visual agnosia, and placidity.

KBS was first identified in 1888, but did not come into clinical attention until the 1950s, when neurosurgeons began performing bilateral temporal lobectomies to treat epilepsy and seizures, and began noticing patients presenting with this syndrome.^[1]

The prevalence of KBS limited to case series and reports, making the exact prevalence unknown.^[2]

Certain symptoms of KBS such as placidity, hyperorality, hypermetamorphosis may not resolve. Other symptoms of may resolve gradually over time. The course of the syndrome is not well understood. For KBS resulting from reversing etiologies such as epileptic seizures and infections, the prognosis may be better if these reversible causes are recognized early and treated.

The most common risk factors for developing KBS are traumatic brain injury, stroke, and herpes simplex encephalitis in children. However, KBS can be caused by any disease process that causes acute bitemporal injury or by any progressive neurodegenerative disorder that affect the bilateral anterior temporal lobes. Thus, the causes of KBS are very broad, including dementias, encephalitis, traumatic brain injury, cerebrovascular disease, metabolic disturbances, and neoplasms.

Kluver proposed both manifestations of KBS as either permanent or temporary:^[3]

1. Hyperorality (placing non-edible objects in mouth, making licking, sucking, and/or chewing movements)
2. Placidity, blunted affect, and/or apathy
3. Hypermetamorphosis (excessive attentiveness to visual stimuli, and tendency to touch every these visual stimulus, regardless of the history or reward value of that object)

1. Hypersexuality
2. Dietary changes (hyperphagia, pica, coprophagia) (rapid weight gain can occur in some patients, and some may ingest inedible non-food items)
3. Visual agnosia (“psychic blindness”)

KBS does not occur in isolation, but is usually accompanied with a complex neuropsychiatric syndrome that can include aphasia, cognitive impairment, dementia, and/or seizures.

The destruction of the bilateral temporal lobes (with amygdala involvement) bilaterally, results in a disturbance to the limbic networks that link to other cortical and subcortical circuits responsible for emotions and affect.

• Neurodegenerative Disorders
  • Alzheimer disease
    • Can present with memory loss, personality changes that may resemble KBS
  • Frontotemporal Dementia (FTD)
    • Progressive deterioration of intellect associated with behavioral and personality changes.
• Prader-Willi Syndrome (PWS)
  • PWS can similarly present with hyperphagia
• Kleine-Levin Syndrome (KLS)
  • KLS can similarly present with hyperphagia
• Wernicke Encephalopathy and Korsakoff Syndrome
  • Individuals with WKS can also present with poor memory, irritability, and behavioural and personality changes
• Personality Change Due to Another Medical Condition

• Neuroimaging with MRI brain may be helpful to assess the degree of temporal lobe injury
• Electroencephalogram (EEG) can be ordered to identify seizures originating from the temporal lobe

Treatment of KBS is symptomatic and similar to how neuropsychiatric symptoms from traumatic brain injury or behavioural and psychological symptoms of dementia (BPSD) might be managed. The main classes of medications that can be used include antidepressants, antipsychotics, mood stabilizers (carbamazepine in particular),^[4] and hormonal agents such as gonadotropin-releasing hormone (GnRH) analogues (e.g. - leuprorelin).