What Is Klüver-Bucy Syndrome?

We all know that the brain is an amazing organ of almost unimaginable complexity. Different areas of the brain have different functions which together allow us to function normally.

Like any organ, the brain is vulnerable to damage. The consequences of damage will vary depending on which part is affected. Here, we will explore what happens when both of our temporal lobes are damaged and how symptoms of Klüver-Bucy syndrome can result.

Overview

Klüver-Bucy syndrome (KBS) describes a rare collection of symptoms that typically arise as a result of damage to the brain.¹ The syndrome is named after neuropsychologist Heinrich Klüver and neurosurgeon Paul Bucy who described the syndrome in monkeys who had undergone a bilateral temporal lobectomy (surgical removal of both temporal lobes).²

KBS typically arises when both of the temporal lobes of the brain are damaged, for example by stroke or trauma.² Our temporal lobes form part of the cerebral cortex and have roles in speech, language, vision, memory, emotions and behaviour.³ 

Bilateral damage to the temporal lobes leads to a number of abnormal behaviours that are characteristic of KBS.¹ Read on to find out more about this unusual condition and how we can manage it. 

Figure.1: The right temporal lobe seen from the side

Credits: BodyParts3D, © The Database Center for Life Science licensed under CC Attribution-Share Alike 2.1 Japan. 

Link to image: https://commons.wikimedia.org/wiki/File:Temporal_lobe_-_lateral_view.png 

Risk factors for and causes of Klüver-Bucy syndrome

Damage to both temporal lobes can occur for a wide variety of reasons. In adults, the most common causes are head injury and stroke. In children, herpes simplex encephalitis is the leading cause.¹ 

Other causes of bilateral temporal lobe damage include:^{1, 2}

• Alzheimer’s disease
• Epilepsy
• Tuberculosis affecting the central nervous system
• Listeria meningoencephalitis
• Huntington’s disease
• Shigellosis
• Lupus (SLE)
• Subdural hygroma

The individual risk factors for the wide range of potential causes are outwith the scope of this article. But speak to your healthcare provider if you want to find out more about a particular cause.

Damage to two regions within the temporal lobes makes a person particularly vulnerable to developing KBS. These are the amygdala and the hippocampus. The amygdala regulates our emotions and behaviour while the hippocampus plays a vital role in the formation and recall of memories.³ 

Signs and symptoms of Klüver-Bucy syndrome

Complete KBS presents with the following symptoms:⁴

1. Visual agnosia: An inability to recognise familiar people, objects and shapes.
2. Hyperorality: A compulsive tendency to place inappropriate objections in the mouth. Hyperorality occurs partly due to the inability to recognise common objects. 
3. Hypersexuality: High levels of inappropriate sexual behaviour. 
4. Disordered eating: Bulimia may be observed and can be associated with marked weight gain.
5. Placidity: Appearing flat in mood and lacking in normal emotional responses such as anger or fear. 
6. Hypermetamorphosis: A tendency to touch and explore everything around you, even if the objects are insignificant. 

Partial Klüver-Bucy syndrome occurs when a person exhibits three or more of the above symptoms and is more common than complete KBS.⁴ The most common combination of symptoms is placidity, disordered eating and hyperorality.¹ People with KBS may also show aggressive behaviour.⁴

Diagnosis

KBS is a rare syndrome and its symptoms overlap with those of more common conditions like Alzheimer’s disease. For this reason, reaching a diagnosis of KBS requires careful evaluation of the clinical features by a healthcare team with expertise in neurological disorders. They will gather information from a variety of sources to help them make their diagnosis:

History and examination

Your healthcare team will take a careful history from you and/or your loved ones to understand your symptoms and how they began. They will seek to understand how your health is normally and whether you are taking any medication. 

For example, a person showing symptoms of KBS could have acquired damage to their temporal lobes as the result of a stroke. In this case, symptoms are likely to have arisen suddenly. The person may have pre-existing medical conditions that increase their risk of stroke, such as hypertension and high cholesterol.²

A thorough neurological examination involves assessing movement, sensation, reflexes and coordination.⁵ A neurological examination can help identify if there are parts of your brain that are not working properly. If KBS has been caused by a stroke, the person may show signs of weakness or confusion.²

Neuropsychological assessment can help to identify cognitive changes that are in keeping with KBS.⁶

Laboratory tests

Blood tests can help to identify the underlying cause of KBS by looking for signs of infection or impaired blood clotting.² 

A lumbar puncture allows doctors to sample the fluid that surrounds the brain and spinal cord which can be sent for analysis. For example, if you have symptoms of KBS that are caused by tuberculosis, then you will likely have high levels of protein and low levels of glucose in your CSF. There may also be a high number of white blood cells present.⁷  

Imaging

A CT or MRI scan may identify damage to the temporal lobes and support a diagnosis of KBS.¹ 

Management and treatment for Klüver-Bucy syndrome

It can be helpful to consider two aspects of treatment for KBS: treatment of the underlying cause and management of the symptoms of KBS. 

Treatment of the underlying cause

We have identified that there is a wide range of underlying conditions that can lead to the development of KBS. Some of these underlying conditions can be managed with specific treatments. For example: 

1. If damage to the temporal lobes has occurred as a result of tuberculosis infection, antitubercular drugs like rifampicin and isoniazid can be given the treat the infection.⁴
2. If damage has occurred due to a subdural hygroma or other space-occupying lesions within the skull, then it may be possible to offer surgery.⁸

Symptomatic management 

Not all conditions causing KBS can be treated directly. Even if specific treatment is available, a person is likely to have residual symptoms. Fortunately, there are several medications that can help manage the symptoms of KBS:

1. Antidepressant medications: Antidepressant medications like fluoxetine (an SSRI) can help manage some of the mood changes seen in KBS.⁹
2. Antipsychotic medications: Medications like haloperidol can manage the behavioural symptoms of KBS.¹
3. Mood stabilisers like carbamazepine can reduce the inappropriate sexual behaviour sometimes seen in people with KBS.¹
4. Leuprolide may also be helpful where sexual behaviours are problematic.¹⁰

Complications

KBS symptoms can cause a person to engage in a variety of dangerous or reckless behaviours. They may place dirty or dangerous inappropriate objects into their mouth which can impact their health and safety. They may cause harm to themselves and others as a result of hypersexuality, which can also lead to legal issues. Disordered eating can lead to a variety of health consequences including weight gain, poor dentition and electrolyte imbalances. Emotional blunting and memory loss can create problems in interpersonal relationships and make it difficult to live independently.¹

FAQs

How can I prevent Klüver-Bucy syndrome

The most common causes of KBS are stroke, head trauma and herpes simplex encephalitis. You can find out how to reduce your risk of stroke here. To reduce your risk of head trauma, take common-sense precautions such as wearing a helmet when cycling and wearing a seatbelt when driving. Take care when drinking alcohol and do so only in moderation.¹¹ Most cases of herpes simplex encephalitis are caused by the HSV-1 virus. According to the World Health Organisation (WHO), HSV-1 can be transmitted if a person comes into contact with the virus in lesions around the mouth or through the exchange of saliva. To reduce your risk of catching HSV-1, ensure you maintain good hygiene practices and avoid coming into contact with active lesions. 

How common is Klüver-Bucy syndrome

KBS is a rare condition. Little academic research has been conducted on the subject and mostly consists of reports about patients with the condition. For this reason, it is difficult to estimate how common KBS is.¹

What can I expect if I have Klüver-Bucy syndrome

If you are suffering from KBS, some of your symptoms may resolve over a number of years whilst others are likely to persist.¹ You will require support from a variety of professionals during the course of your recovery.

When should I see a doctor

If you suspect that you or someone you love has developed symptoms of KBS, speak to your healthcare provider to arrange an assessment.

Summary

Klüver-Bucy syndrome is a rare collection of symptoms that can arise when both temporal lobes are damaged. Characteristic symptoms include placidity, hyperorality, hypersexuality and disordered eating. There are many reasons why the temporal lobes may become damaged, but this most often happens as a result of stroke, head trauma, or herpes simplex encephalitis.

If your healthcare professional suspects you have symptoms of KBS, they will conduct a thorough assessment which may include blood tests, lumbar puncture and imaging studies.

Treatment options vary depending on the underlying cause of KBS. There are a number of medications available to help manage the symptoms. Some symptoms may continue indefinitely, whilst others can improve with time.