Klüver–Bucy syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 15, 2016
StartDiseasesKlüver–Bucy syndrome

Klüver–Bucy syndrome is an extremely rare condition that is caused by damage to both sides of the temporal lobe of the brain. The temporal lobes are involved in memory, and the amygdala, which are two almond-shaped structures found in the temporal lobes that regulate emotional responses, memory, and decision-making can also be affected by Klüver–Bucy syndrome. This syndrome strikes men and women equally. 

Contents

Definition & Facts

Klüver–Bucy syndrome was named for Heinrich Klüver and Paul Bucy. Klüver first observed the disorder in rhesus monkeys after Bucy had destroyed their temporal lobes in an experiment in the 1930s. Klüver noticed that these symptoms correlated to those that had been described in 1881.

Other cases were seen in the mid-1970s in people who had suffered from meningoencephalitis, an infection of the meninges which are the membranes that cover and protect the brain.

Symptoms & Complaints

The symptoms of Klüver–Bucy syndrome include compulsive sexual behavior and the urge to put objects in one's mouth. Patients also suffer from amnesia. With Klüver–Bucy syndrome, the patient can no longer create new memories nor retrieve old ones.

Though their vision is unaffected, patients with Klüver–Bucy syndrome do not understand what they see and can no longer recognize faces or objects that were once familiar to them, a condition called agnosia. They also have an insatiable appetite and eat things that are indigestible or inappropriate, a condition known as pica. Other symptoms resemble those of dementia

Klüver–Bucy syndrome patients are placid, nonaggressive and unemotional. In the case of the rhesus monkeys, those with Klüver–Bucy syndrome lost their fear of snakes. Their fear did not return even when the snakes attacked them.

The symptoms of Klüver–Bucy syndrome resemble the symptoms of other conditions such as porphyria, Alzheimer's disease, and carbon monoxide poisoning. Many patients with Klüver–Bucy syndrome improve over time.

The symptoms of Klüver-Bucy also encompass the symptoms of underlying diseases. The symptoms of encephalitis, a cause of Klüver-Bucy syndrome, can be mild, though in severe cases the person suffers vomiting, headache, a stiff neck, personality changes, and seizures.

Those with encephalitis may also experience paralysis of an arm or a leg, double vision with pupils of different sizes (anisocoria), hearing loss, and speech impairment. In some cases, they become drowsy and eventually sink into a coma.

Causes

Klüver–Bucy syndrome can be caused by trauma to the brain or a degenerative disease of the brain. It can also be a complication of brain tumors or brain infections, especially encephalitis caused by the herpes simplex virus (herpesviral encephalitis). This virus belongs to the same family of viruses that causes cold sores. When it attacks the brain, the virus causes bleeding, necrosis, and inflammation that’s usually restricted to the temporal lobe.

Klüver–Bucy syndrome can also be a complication of Whipple's disease. This is a bacterial infection that normally affects the gastrointestinal tract, though the bacteria can also travel to the brain. It is treated with antibiotics but can be fatal if left untreated, even if it does not affect the brain.

Tuberculosis meningitis is also caused by a bacteria. In this case, the bacteria that causes tuberculosis, Mycobacterium tuberculosis, travels to the brain and damages the temporal lobe. The people most at risk are babies, the elderly, people with weakened immune systems, and people without access to adequate health care.

Medical researchers have seen symptoms of Klüver–Bucy syndrome appear in people who have suffered concussions, so in some cases the brain damage does not have to be severe to result in the syndrome.

Diagnosis & Tests

Though computed tomography (CT) scans and magnetic resonance imaging (MRI)s can detect damage to the temporal lobe, they are not enough to diagnose Klüver–Bucy syndrome. It is very unusual for a patient to display all of its symptoms; patients have to display at least three of the symptoms for a diagnosis to be made.

Doctors can perform blood tests and examine a patient’s cerebrospinal fluid if they suspect herpes simplex encephalitis or another pathogen has attacked the brain. The DNA of a suspect virus can be identified through the polymerase chain reaction test. Early detection is crucial because treating diseases before they attack the patient’s brain can prevent Klüver–Bucy syndrome.

Treatment & Therapy

There is no cure for Klüver–Bucy syndrome, though it is not life-threatening. It is important for the patient to be monitored so that they do not ingest inappropriate objects or eat to the point where they endanger their health. They also have to be prevented from acting out in sexually inappropriate ways.

Psychiatric medications may help. Some patients who were treated with carbamazepine showed some improvement. Carbamazepine is normally used to treat epilepsy, schizophrenia, and bipolar disorder. The drug usually comes in a chewable tablet that is taken with liquid or food to ease any irritation of the stomach. It is not known how long it takes for the drug to finally work, but it lowers the excitability of the neurons in the brain and inhibits the transmission of pain signals. 

SSRIs, or selective serotonin reuptake inhibitors may also help people with Klüver–Bucy syndrome. These drugs also treat depression by increasing the levels of a neurotransmitter called serotonin in the brain. However, some medical experts believe that giving a Klüver–Bucy syndrome patient such drugs may delay their recovery.

Doctors usually treat herpes simplex encephalitis with antiviral drugs and anticonvulsants if the patient is having seizures. Most people make a full recovery from this disease after two or three weeks.

Prevention & Prophylaxis

The way to prevent most cases of Klüver–Bucy syndrome is the prevention or early treatment of herpes simplex encephalitis and other brain infections. In some Klüver–Bucy syndrome patients, their herpes simplex encephalitis went undiagnosed and untreated for too long, and put them at risk for Klüver–Bucy syndrome.

Since herpes is contagious, it is important for people to avoid anyone with herpes simplex encephalitis and to see a doctor if they suspect that they have an infection anywhere in their body.