Klüver–Bucy syndrome

Overview

Klüver–Bucy syndrome is a rare neurobehavioral disorder that results from damage to the medial temporal lobes of the brain, particularly the amygdala and hippocampus. It is characterized by a distinct cluster of behavioral and cognitive abnormalities, including hyperorality, hypersexuality, visual agnosia, and placidity. The syndrome was first described in rhesus monkeys in the 1930s by Heinrich Klüver and Paul Bucy, and later observed in humans with bilateral temporal lobe damage. The condition typically arises after traumatic brain injury, infections, or degenerative neurological diseases.

Causes

Klüver–Bucy syndrome results from bilateral lesions of the medial temporal lobes, especially involving the amygdala and adjacent structures. Common causes include:

• Traumatic brain injury

• Herpes simplex encephalitis (a viral infection of the brain)

• Stroke affecting the temporal lobes

• Neurosurgical procedures involving the temporal regions

• Neurodegenerative diseases, such as Alzheimer’s disease or Pick’s disease

• Brain tumors or other space-occupying lesions in the temporal lobes

Symptoms

The hallmark symptoms of Klüver–Bucy syndrome reflect the loss of normal limbic system functions and may include:

• Hyperorality: Compulsive tendency to examine objects by mouth or put non-food items in the mouth

• Hypersexuality: Increased or inappropriate sexual behavior and urges

• Visual agnosia: Inability to recognize familiar objects or people despite normal vision (also called psychic blindness)

• Placidity: Marked reduction in fear and aggression, even in threatening situations

• Memory disturbances: Short-term memory loss or confusion

• Emotional blunting: Decreased emotional responsiveness or flattened affect

• Increased exploratory behavior: Compulsive touching or examining of objects

Not all patients will display the full spectrum of symptoms; the presentation can vary based on the extent and location of brain damage.

Diagnosis

Diagnosis of Klüver–Bucy syndrome is clinical, based on the recognition of its characteristic behavioral symptoms and confirmed with imaging studies. Diagnostic steps include:

• Neurological examination to assess cognitive and behavioral changes

• Neuroimaging (MRI or CT scan) to identify bilateral temporal lobe damage

• Electroencephalogram (EEG) if seizures are suspected

• Neuropsychological testing to evaluate memory, recognition, and emotional response

• Medical history review for any traumatic, infectious, or degenerative causes

Differential diagnosis includes other neurological and psychiatric disorders such as frontotemporal dementia, schizophrenia, and advanced Alzheimer's disease.

Treatment

There is no specific cure for Klüver–Bucy syndrome, and treatment focuses on managing symptoms and underlying causes. Therapeutic strategies include:

• Pharmacologic therapy:

  • Antipsychotics or mood stabilizers for behavioral control

  • Anticonvulsants if seizures are present

  • Selective serotonin reuptake inhibitors (SSRIs) for hypersexuality or emotional regulation

• Behavioral therapy: Structured behavioral interventions to reduce inappropriate actions

• Supportive care: Supervision and environmental modifications to ensure safety

• Treatment of the underlying condition: Antiviral therapy for encephalitis, surgical intervention for tumors, or rehabilitation post-trauma

Prognosis

The prognosis of Klüver–Bucy syndrome depends on the cause and extent of brain damage. In cases caused by reversible conditions like viral encephalitis, partial recovery is possible with early intervention. However, in cases of irreversible brain injury or progressive neurodegenerative diseases, the prognosis is generally poor. Long-term management may be necessary to support behavioral control and improve quality of life. With appropriate care, some individuals can achieve partial functional recovery and adapt to daily life.