Bulbar Brain Syndrome: Causes, Symptoms & Treatment

Bulbar brain syndrome is a complication of midbrain syndrome. Such a syndrome results from compression of brain structures following increases in intracranial pressure within the middle cranial fossa. While midbrain syndrome is usually reversible, bulbar brain syndrome is at high risk for final brain death.

What is bulbar brain syndrome?

With the exception of the cerebellum, the brain stem includes all brain parts below the diencephalon. Thus, in addition to the midbrain (mesencephalon) and bridge (pons), the extended medulla (medulla oblongata) is also part of the brainstem. Bulbar brain syndrome is present when there is a total failure of brainstem functions. This failure may be reversible and usually results from bilateral acute damage to the pons and medulla oblongata. In most cases, the cause of the failure symptoms is due to entrapment of the brainstem structures by the cerebellar tonsils. This phenomenon usually occurs in the context of increases in intracranial pressure and is referred to as lower entrapment. To be distinguished from this is upper entrapment, which results in a so-called midbrain syndrome. Bulbar brain syndrome is usually a complication of midbrain syndrome. Thus, the two phenomena are usually due to the same primary causes.

Causes

Midbrain syndrome results from increases in intracranial pressure within the cranial fossa media. The increase in pressure within the skull results in the displacement of brain structures. Due to the limited volume of the skull, the brain components can only move out to a limited extent and become jammed. For example, in midbrain syndrome, the midbrain becomes jammed in the tentorial slit, resulting in failure of the compressed structures. Causes of the triggering intracranial pressure increase may be strokes or trauma-related hemorrhage. Space-occupying lesions also cause intracranial pressure to rise. The same applies to edema and cerebrospinal fluid outflow disorders. The latter phenomenon is referred to in all processes that block the draining cerebrospinal fluid pathways and thus obstruct the outflow of cerebrospinal fluid into the external cerebrospinal fluid space. Midbrain syndrome, or upper entrapment, develops into lower entrapment if intracranial pressure continues to rise, resulting in bulbar brain syndrome.

Symptoms, complaints, and signs

The symptomatology of bulbar brain syndrome consists of acute failure of brainstem reflexes. In most cases, patients with bulbar brain syndrome are comatose patients who show only hypotonic muscle tone within the skeletal muscles. Affected individuals also suffer from areflexia. Thus, the reflexes of the skeletal muscles fail. The eye muscles also no longer show reflex behavior. For this reason, there is persistent mydriasis. In addition, disturbances of the vital functions are usually present. For example, respiratory drive is often diminished and results in biotic or gasping breathing. The heartbeat is also characterized by bradycardia. While there is still time in midbrain syndrome, bulbar brain syndrome is considered an acute life-threatening condition that must be resolved as soon as possible. Because there is an undersupply of oxygen to the medulla oblongata due to compression, the central regulatory centers may be irreversibly damaged. Such damage would result in circulatory arrest (cardiovascular failure).

Diagnosis and course

The neurologist makes the diagnosis of bulbar brain syndrome after checking brainstem reflexes. If there is a failure, the diagnosis is considered confirmed. Examination of brainstem reflexes also allows differential diagnosis of bulbar brain syndrome from midbrain syndrome. In principle, the gradual transition from muscular hypertonia in the sense of extensor synergisms to muscular hypotonia is considered to point the way for the diagnosis of a midbrain syndrome. Already at the diagnosis of a midbrain syndrome, intracranial pressure should be determined. In addition, imaging helps to determine the cause of the progressive increase in intracranial pressure. In most cases, the neurologist uses an MRI when midbrain or bulbar brain syndrome is suspected. In the slice images, tumors under contrast medium administration, for example, show a relatively characteristic image. The same is true for hemorrhages. The prognosis is rather unfavorable for patients with bulbar brain syndrome. It is an acutely life-threatening condition.

When should you see a doctor?

In the case of bulbar brain syndrome, medical examination and treatment must take place in any case. In the worst case, the syndrome can cause the death of the affected person. However, since bulbar brain syndrome usually occurs in coma patients, no additional examination is necessary. A physician should be called in, however, if the affected person no longer displays ordinary reflexes. In this case, the eyes can also no longer be moved. Gasping for breath or loss of consciousness may also indicate the syndrome and must be investigated. In acute emergencies, immediate treatment by an emergency physician is necessary. If the brain is irreversibly damaged, heart failure usually results. The doctor should be consulted if the patient suddenly stops showing reflexes for no particular reason. The examination can be performed by a neurologist. Unfortunately, treatment is not possible in most cases, so the affected person is dependent on a stay in the hospital.

Treatment and therapy

Up to the bulbar brain syndrome stage, compression of midbrain structures is usually considered reversible. From the failure of brainstem reflexes onward, complete recovery of patients is usually impossible. The focus of therapy in patients with bulbar brain syndrome is to ensure vital functions. In addition, brain metabolism is preserved as much as possible. Ventilation is provided by means of controlled hyperventilation. In addition to catecholamines, physicians give volume substitution. The secondary therapeutic goal is causal treatment to halt the progressive increase in intracranial pressure. The primary cause of the pressure increase must be eliminated to effectively lower intracranial pressure and thus prevent brain death. Initially, mannitol is given to lower the pressure. Depending on the cause, ventricular drainage or craniotomy may be performed. During invasive procedures, continuous monitoring of pressures and vital signs is indicated. Intensive care monitoring is available for surveillance. Final removal of the primary cause is usually neurosurgical. If hemorrhage occurs, hematoma evacuation must take place. Causative space-occupying lesions require tumor extirpation. If patients survive bulbar brain syndrome, severe damage such as apallic syndrome often remains. Supportive measures for rehabilitation are always indicated after midbrain or bulbar brain syndrome. While these measures are relatively promising after midbrain syndrome, there is much less chance of success after bulbar brain syndrome.

Outlook and prognosis

The prognosis in bulbar brain syndrome is generally very poor, resulting in brain death in most cases. As a result of this, the patient then also dies. Death can only be delayed by symptomatic treatment, thus increasing the patient’s life expectancy. However, a complete cure can no longer be achieved in bulbar brain syndrome. Patients are dependent on artificial respiration as part of the treatment. The pressure in the brain must also be lowered to avoid brain death. The exact life expectancy depends to a large extent on the health circumstances and the severity of the bulbar brain syndrome. Only in very rare cases can the affected person survive. In these cases, however, the brain takes a high damage, so that the affected person suffers from motor and mental limitations. These can no longer be treated and are thus irreversible. If no treatment occurs in bulbar brain syndrome, the affected person usually dies after a short time due to brain death. Before death, the patient usually falls into a coma and becomes unresponsive.

Prevention

Bulbar brain syndrome can be prevented only to the extent that causative compressions of the medulla oblongata can be prevented. Prevention is usually the responsibility of neurologists treating the preceding midbrain syndrome. Close monitoring of intracranial pressure and effective reduction of pressure ratios are indicated during treatment of midbrain syndrome to prevent bulbar brain syndrome.

Follow-up

The options for follow-up care are usually very limited in bulbar brain syndrome. It is imperative that the syndrome itself be treated by a physician to prevent the death of the affected person.Early diagnosis and treatment of the syndrome have a very positive effect on the further course of the disease and can prevent further complications. The affected person usually receives medication to lower blood pressure. It is important to ensure that these are taken regularly, and the interaction with other medications should also be clarified. Similarly, surgical intervention is usually necessary to completely treat bulbar brain syndrome. After such an operation, the affected person must in any case rest and take care of his body. In this case, sports activities or other strenuous activities should be avoided in any case in order to accelerate the healing process. If the bulbar brain syndrome has been caused by a tumor, further and above all regular examinations of the entire body are advisable in order to detect and remove further tumors at an early stage. In most cases, however, the life expectancy of the patient is limited by the bulbar brain syndrome. Contact with others affected by the syndrome can also be useful, as this often leads to an exchange of information.

Here’s what you can do yourself

Bulbar brain syndrome is a medical emergency. When it occurs, emergency medical services must be alerted and first aid given to the affected person. After treatment, the patient must initially take it easy. Depending on the severity of the syndrome, a number of medicinal or therapeutic measures are then indicated. If neurological disorders occur as a result of the syndrome, this may indicate damage to the brain, which must be diagnosed in the course of further examinations. In the case of severe brain damage, the patient is often also in need of care and psychological help. If the bulbar brain syndrome is positive, rest and moderate exercise are usually sufficient for follow-up. The patient should watch for unusual symptoms and inform the physician. It is also important to discuss any side effects or interactions of the prescribed medications with the doctor in order to avoid major complications. If, despite all measures, the patient’s health deteriorates, bulbar brain syndrome must be taken to a neurologist. The medical professional in charge can provide further tips for self-help measures and thus help the bulbar brain syndrome to subside quickly.