Midbrain syndrome is the result of an increase in intracranial pressure in the cranial fossa media and is related to compression of the midbrain structure. The most common causes of the syndrome are hemorrhage and edema. Treatment is usually intensive care and includes preservation of vital functions and usually neurosurgical pressure reduction.
What is midbrain syndrome?
The mesencephalon forms a portion of the brain stem. Neurologists also refer to the part of the brain between the pons and diencephalon as the midbrain. The midbrain localizes pathway systems and nerve nuclei that are vital to humans. Pressure damage of the midbrain is summarized as midbrain syndrome, which can be accompanied by different symptoms. Primarily, an increase in intracranial pressure sets the stage for acute midbrain symptoms. As intracranial pressure increases, brain structures may leave their physiological position and become jammed. Usually, the midbrain becomes jammed in the tentorium cerebelli, the so-called cerebellar vermis. This is a transverse meningeal structure between the occipital lobe in the supratentorial space and the cerebellum in the infratentorial space. Jamming of the cerebral portion can only occur after an increase in pressure in the area of the cranial fossa media. The causes of pressure increase in this area may be of various natures.
Causes
Acute midbrain syndrome is preceded by brain pressure-increasing processes such as edema. Such edema formations can occur in the context of various diseases, such as brain tumors, cerebral infarcts, or toxic ischemia. Strokes can also cause cerebral edema. In principle, however, strokes and tumors can result in a midbrain syndrome even without concomitant edema formation. All of the above processes cause intracranial pressure to increase. There is limited space within the skull. Leaking blood in the course of a stroke takes up more or less space. The same is true for space-occupying lesions in the brain as well as water accumulation in the sense of edema. Since the brain structures within the cranial cavity can hardly move out of the way, they are pressed against each other and become jammed. The result can be midbrain syndrome. In individual cases, CSF outflow disorders are also the primary cause of jamming. CSF is the term used to describe the cerebrospinal fluid that washes around the central nervous system. In individual cases, midbrain syndrome can also be caused by traumatic brain injury, poisoning, or cardiac arrest.
Symptoms, complaints, and signs
From a clinical perspective, midbrain syndrome can be divided into three distinct stages, each characterized by different symptoms. Basically, there is a progressive loss of consciousness. In addition, the pupillary reflexes fail during the course of the disease. The initial stage is characterized by tachycardia and pathological Cheyne-Stokes respiration. Affected individuals sweat and no longer have pain stimulus responses. Pathologic reflexes occur. Babinski’s signs, for example, are positive. In the third stage of acute midbrain syndrome, patients suffer from light-rigid pupils. In addition, extensor synergisms occur in the form of so-called decerebration rigidity. This symptom is explained by the failure of all inhibitory pathways. The reflexes are overactive in this phase. This is also referred to as hyperreflexia. Since midbrain syndrome leads to coma during the third stage, the patients’ vital functions are threatened in the late course of the syndrome. As damage progresses due to increasing intracranial pressure, midbrain syndrome usually transitions smoothly into life-threatening bulbar brain syndrome.
Diagnosis and course of the disease
The neurologist obtains initial clues to midbrain syndrome from the history. Standard reflex testing reinforces the initial tentative diagnosis. To confirm the diagnosis of midbrain syndrome, the neurologist uses diagnostic imaging. In most cases, he orders an MRI. The constriction of the midbrain is clearly visible on the slice image. Measurement of intracranial pressure is mandatory if indicated. The measurement is repeated continuously during the course in order to detect a continuous increase in pressure as early as possible and to be able to intervene. The prognosis for patients with midbrain syndrome depends on the time of diagnosis.Diagnosis at the first stage has a positive prognostic impact.
Complications
Due to the midbrain syndrome, patients experience various limitations and discomforts. These can lead to paralysis or to further disturbances of sensibility and thus have a very negative effect on the patient’s daily life and quality of life. It is not uncommon for those affected to be dependent on the help of other people in their daily lives, and they are usually no longer able to perform simple activities. It is not uncommon for this to result in rigidity and unusual breathing. Those affected can also fall into a coma and no longer actively participate in life. Especially for the relatives, children or partners, the midbrain syndrome can lead to very severe psychological discomfort and stress, so that they are also dependent on psychological treatment. As a rule, treatment of the midbrain syndrome can take place with the help of medication, whereby this is usually aimed at the underlying disease. However, it cannot be generally predicted whether this will result in a positive course of the disease. In general, the life expectancy of patients is not reduced or limited by midbrain syndrome.
When should you see a doctor?
A disturbance of consciousness is a first sign, of a present disease of the brain. A visit to the doctor is necessary as soon as there are irregularities of consciousness, headaches or attention deficits. A drop in performance, problems with concentration or dysfunctions should be examined by a doctor. If a loss of consciousness occurs, emergency medical services must be alerted immediately. Emergency care as well as intensive medical care for the affected person is necessary. Medical tests are performed so that the cause of the symptoms can be clarified and treated. Bystanders are required to take first aid measures until the emergency physician arrives. This is the only way to ensure the survival of the victim. In case of irregularity of respiratory activity, disturbances of reflexes as well as heavy sweating, a doctor is needed. In particular, loss of pupillary reflexes must be discussed with a physician. If loss of pain sensation occurs or existing symptoms increase in intensity, a physician must be consulted. A pale complexion, apathy as well as apathy are signs of a present disease. Since midbrain syndrome can lead to a life-threatening condition, a doctor should be consulted as soon as there is an increasing tendency to feel unwell or ill. Impaired memory, disorientation, and loss of cognitive performance should be examined by a physician.
Treatment and therapy
Treatment of midbrain syndrome depends on the stage and cause of the manifestation. The main focus of treatment is to ensure vital functions. In addition, cerebral metabolism must be kept going and intracranial pressure monitored. To maintain vital functions, patients receive ventilation with controlled hyperventilation. Conservative drug therapy corresponds to the administration of catecholamines. In addition, volume substitution is usually required. Once vital signs are stabilized, lowering intracranial pressure is considered the ultimate goal of therapy. The most effective method of lowering intracranial pressure depends on the primary cause of the pressure increase. In addition to neurosurgical lowering, mannitol or ventricular drainage may be important starting points. During pressure reduction, it is important to continuously monitor not only the pressure conditions but also the patient’s vital functions. This monitoring is carried out by means of intensive care monitoring. The acute reduction of intracranial pressure is followed by the elimination of the primary cause. This cause is eliminated by means of neurosurgical intervention. If the primary cause is leaked blood, for example, hematoma clearance is performed as causal therapy. In contrast, tumor extirpation is performed for causative space-occupying lesions. Whether patients fully recover from midbrain syndrome depends on the severity of the contusions and the areas affected; rehabilitative measures can promote recovery from any long-term sequelae.
Outlook and prognosis
Midbrain syndrome offers a relatively poor prognosis and means a significant reduction in quality of life for those affected.At the onset of the syndrome, there is usually already significant brain damage, which leads to serious complications or death of the patient. Severe symptoms such as increased intracranial pressure or coma often take a severe course. Patients must be artificially ventilated and are usually unresponsive. If the course is positive, there is a prospect of recovery, insofar as no severe physical damage has occurred. In general, the prognosis depends on the timing of treatment and the severity of the causative traumatic brain injury. If the trauma is treated promptly by a physician, the prognosis is better. In the absence of treatment, midbrain syndrome is always fatal. The prognosis is made by the neurologist in charge in consultation with surgeons and other specialists. To make the prognosis, the severity of the trauma is taken into account, as well as the previous course and any physical and mental damage. The prognosis is relatively reliable because organ damage that has already occurred usually cannot be treated, and once a traumatic brain injury has been overcome, it does not necessarily cause complications.
Prevention
Midbrain syndrome can be prevented only to the extent that an increase in pressure in the area of the cranial fossa can be prevented. The preventive measures in the context of cerebral infarction, for example, can be counted in the broadest sense as preventive measures.
Aftercare
In most cases of midbrain syndrome, the patient has very few and usually very limited options for aftercare, so the affected person is primarily dependent on early diagnosis and rapid treatment of this disease to prevent further complications and symptoms. There can be no self-healing, so treatment by a physician is always necessary. Most sufferers rely on surgical intervention for midbrain syndrome. The affected person should in any case take it easy after such an operation, and bed rest should also be observed. It is also not uncommon for various medications to be taken to alleviate the symptoms. The doctor’s instructions must be followed, and care must be taken to ensure that the medication is taken regularly and in the correct dosage. Most patients also need psychological support during the treatment and are also dependent on the help of their own family in everyday life. No general prediction can be made about the further course of midbrain syndrome in this context, as it is highly dependent on the time of diagnosis.
What you can do yourself
In the case of midbrain syndrome, there are no self-help options available to the affected person in most cases. In any case, medical assistance is necessary to reduce and limit the discomfort and symptoms of this syndrome. In many cases, the relatives or parents of the affected person also suffer from severe psychological complaints or depression. In this case, psychological treatment is useful in order not to burden the patient with this. The loving help and care of the relatives can also have a positive effect on the course of the disease of midbrain syndrome. Should the affected person lapse into a coma, no direct help can usually be provided. Daily care and prevention of mental discomfort is useful in this case. In the case of a midbrain syndrome, the affected person is dependent on regular checks and examinations, which should be carried out especially at an older age or in the case of permanent complaints. Since breathing is also negatively affected by the syndrome, the affected person should take it easy and not engage in any strenuous or athletic activities. Unfortunately, it is not possible to generally predict whether midbrain syndrome will result in a reduced life expectancy.
