Kluver Bucy syndrome

Kluver Bucy syndrome is a rare neuro-psychiatric disorder characterized by inappropriate sexual behaviors and putting objects in mouths ¹. Other signs and symptoms, include a diminished ability to visually recognize objects (visual agnosia), loss of normal fear and anger responses, memory loss, distractibility, seizures, and dementia. Kluver Bucy syndrome is associated with damage to both of the anterior temporal lobes of the brain, especially hippocampus and amygdala ². Cases have been reported in association with herpes encephalitis and head trauma ³.

Kluver Bucy syndrome is a very rare disease that affects males and females equally. Human Kluver Bucy syndrome is more or less restricted to case series and reports. Hence the exact prevalence is difficult to estimate.

Treatment is symptomatic and supportive and may include the use of psychotropic medications ³.

Kluver Bucy syndrome cause

Kluver Bucy syndrome is the result of damage to the temporal lobes of the brain. This may be the result of trauma to the brain itself, or the result of other degenerative brain diseases, tumors, or it can be caused by some brain infections, most commonly herpes simplex encephalitis (a viral brain infection).

Kluver Bucy syndrome is known to be associated with several pathologies. The most common pathologies leading to the development of Kluver Bucy syndrome are head injury and stroke in adults and herpes simplex encephalitis in children. There are many case reports of several conditions (listed below) ranging from infections like shigellosis to methamphetamine withdrawal. But how Kluver Bucy syndrome occurred in these conditions remains unclear.

• Herpes simplex encephalitis ⁴
• Stroke (temporal lobe infarction – usually bilateral) ⁵
• Listeria meningoencephalitis ⁶
• Traumatic brain injury ⁷
• Central nervous system tuberculosis ⁸
• Primary cerebral Whipple disease ⁹
• Alzheimer disease ¹⁰
• Pick disease ¹¹
• Hypoglycemia ¹²
• Acute sporadic porphyria ¹³
• Huntington disease ¹⁴
• Juvenile neuronal lipofuscinosis ¹⁵
• Toxoplasmosis
• Epilepsy ¹⁶
• Parkinson disease
• Heat stroke ¹⁷
• Shigellosis ¹⁸
• Methamphetamine withdrawal ¹⁹
• Systemic lupus erythematosus ²⁰
• Anoxic-ischemic encephalopathy ²¹
• Neurocysticercosis ²¹
• Non-Hodgkin lymphoma ²²
• Mycoplasmal bronchitis ²³
• Methotrexate leukoencephalopathy ²⁴
• Subdural hygroma ²⁵

Kluver Bucy syndrome pathophysiology

The significant clinical symptoms of Kluver Bucy syndrome are produced by the destruction of either the temporal neocortex or the amygdala bilaterally. The full syndrome is rarely seen in humans because the anterior temporal lobe dysfunction is usually less severe in humans when compared to that following total temporal lobe resection in monkeys ²⁶.

The exact anatomical basis of Kluver Bucy syndrome is still controversial. Kluver Bucy syndrome is thought to occur due to the disturbances in the temporal portions of limbic networks that connect with multiple cortical and subcortical circuits to modulate emotional behavior and affect ²⁶. A sine qua non for Kluver Bucy syndrome is the involvement of medial temporal lobe regions along with bilateral lesions of the Ammon horn ²⁷. Even though Kluver Bucy syndrome is always thought to follow bilateral malfunctions of the temporal lobes, it is important to note that the amygdala, uncus, hippocampus, orbitofrontal and cingulate gyri, and insular cortex have an important role in its pathogenesis.

Theories regarding the cause of Kluver Bucy syndrome:

• Norman Geschwind theory: Interruption of visual input to limbic circuit leading to disconnection syndrome produces Kluver Bucy syndrome ²⁸.
• Muller theory: Disconnection of the pathways connecting the dorsomedial thalamus with the prefrontal cortex and other limbic areas lead to Kluver Bucy syndrome. These pathways are essential for memory and emotional regulation ²⁹.

The origin of various symptoms of Kluver Bucy syndrome are explainable as follows:

• Rage is produced by the involvement of the ventromedian nucleus of thalamus and amygdala ³⁰.
• A permanent “hypersexed state,” produced by discrete bilateral lesions of the lateral amygdaloid nucleus. Temporal lobe seizures may produce a transient state.
• Visual agnosia results from bilateral ventral temporal ablations and temporal lobectomies.

Kluver Bucy syndrome symptoms

Kluver Bucy syndrome major symptoms may include excessive oral tendencies with an urge to put all kinds of objects into the mouth, hypermetamorophosis (a need to explore everything), memory loss, emotional changes, extreme sexual behavior, indifference, placidity, visual distractibility and visual agnosia (difficulty identifying and processing visual information). An almost uncontrollable appetite for food may also be noted. There may also be other symptoms associated with dementia (loss of reason) as well.

The following clinical features characterize Kluver Bucy syndrome ²:

• Hyperorality – Socially inappropriate lickings and a strong compulsion to place objects inside the mouth
• Hypermetamorphosis (excessive attentiveness to visual stimuli with a tendency to touch every such stimulus)
• Hypersexuality – Lack of social restraint in terms of sexuality, with inappropriate sexual activity and attempted copulation with inanimate objects
• Eating disorder – Objects are placed in the mouth and explored with the tongue to counteract visual agnosia.
• Bulimia, which is an eating disorder characterized by binge eating, followed by purging, is also markedly seen and may cause weight gain.
• Placidity – Flat affect and reduced response to emotional stimuli
• Visual agnosia (psychic blindness) – Inability to recognize familiar objects or faces presented visually
• Amnesia.

Patients having a combination of three or more different elements listed above are described as having partial Kluver Bucy syndrome ⁸.

Kluver Bucy syndrome symptoms in adults

Kluver Bucy syndrome clinical features in adults:

• Hyperorality
• Hypersexuality
• Eating disorder – Objects are placed in the mouth and explored with the tongue to counteract visual agnosia. Bulimia, which is an eating disorder characterized by binge eating, followed by
• purging, is also markedly seen and may cause weight gain.
• Placidity
• Visual agnosia
• Amnesia.

Placidity, hyperorality, and dietary changes are the most commonly occurring symptoms in Kluver Bucy syndrome.

Kluver Bucy syndrome symptoms in children

Kluver Bucy syndrome in children usually occurs secondary to herpes simplex encephalitis with classic features occurring only in a few.

• Marked indifference
• Bulimia and hyperorality
• Lack of emotional attachment towards the family
• Hypersexuality:
  • The frequent holding of genitals
  • Intermittent pelvic thrusts
  • Rubbing of genitals to the bed after lying prone

Kluver Bucy syndrome complications

Due to hyperorality and hypermetamorphosis, the patient may try to put whatever objects he comes across into his mouth, which can be dangerous.

Due to hypersexuality, he may try to engage in sex with others whom he does not even know, leading to criminal procedures against the patient there is no awareness of the diagnosis.

Bulimia can cause weight gain, electrolyte disturbance, and poor oral hygiene.

Kluver Bucy syndrome diagnosis

The diagnosis of Kluver Bucy syndrome is mainly clinical. Once diagnosed, proper evaluation to find out the underlying pathology will be helpful in the overall management.

Magnetic resonance imaging of the brain is useful in identifying the extent of temporal lobe damage.

Electroencephalogram is also useful to identify seizures originating especially from the temporal lobe.

In head injury and other conditions producing a long duration of loss of consciousness, the appropriate staging of the consciousness is possible with the Modified Innsbruck Remission Scale, which includes the Kluver Bucy phase as well ³¹.

Kluver Bucy syndrome treatment

The treatment of Kluver Bucy syndrome can be challenging due to the facts that there is no specific treatment for the condition, and the clinical course will vary from patient to patient. Most of the treatment focuses on managing the symptoms. The main drugs used in the management are:

• Mood stabilizers
• Antidepressants (selective serotonin reuptake inhibitors)
• Antipsychotic drugs
• Carbamazepine
• Leuprolide

Carbamazepine and leuprolide are used to reduce the sexual behavioral abnormality, whereas haloperidol and anticholinergics are useful in treating behavioral abnormalities associated with Kluver Bucy syndrome ³².

Kluver Bucy syndrome prognosis

There is no cure for Kluver Bucy syndrome ³³. The disorder is not life-threatening, but the patient can be difficult to manage. With treatment, symptoms may slowly decline.

Some Kluver Bucy syndrome features (i.e., hyperorality, placidity, hypermetamorphosis) persist indefinitely, whereas others gradually resolve over several years.

The clinical course of Kluver Bucy syndrome varies among the case reports.

Kluver Bucy syndrome occurring secondary to epileptic seizures, infections or post-infectious, and traumatic brain injuries may have a better prognosis as many of the damages would be reversible if recognized early and managed appropriately.

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