Retrograde amnesia is the loss of memory for events that preceded an injury or illness that caused a violation of mental function. Pathology occurs with TBI, strokes, metabolic encephalopathies and toxic brain lesions. Memory impairment is accompanied by disorientation of the patient, emotional arousal, illogical actions. To diagnose the causes of retrograde amnesia, CT and MRI of the brain, electroencephalography, echoencephalography are required. Treatment includes elimination of the root cause of amnesia, complex neuroprotective therapy, methods of psychotherapy and autogenic training.
ICD 10
R41.2 Retrograde amnesia
General information
Amnesic syndrome is one of the most frequent mental consequences of damage to the structures of the central nervous system. Memory loss associated with trauma or acute illness, according to the anamnesis period, is divided into retrograde, anterograde and congrade. Often there is a combined disorder – anteroretrograde amnesia. Memory loss is a serious medical and social problem, since it is associated with severe organic diseases in neurology and causes difficulties with the patient’s adaptation after intensive treatment.
Causes
Cerebral injuries of traumatic, infectious, toxic or other etiology are recognized as the main factor in the development of retrograde amnesia. The most common causes of impaired memory and reproduction mechanisms include:
- Traumatic brain injuries (TBI). The duration of the period about which the patient’s memories were lost varies from a few minutes to weeks and even months. The intensity of amnesia often correlates with the severity of the injury.
- Disorders of cerebral circulation. Retrograde amnesia is included in the list of typical signs of stroke. It is often supplemented by congruent memory disorders – the absence of memories of the period of switched-off consciousness. Much less often, this condition develops with transient ischemia.
- Infectious and inflammatory diseases. Memory disorders occur with meningitis and encephalitis, which are accompanied by periods of disturbed consciousness and other neurological symptoms. Amnesia is typical for herpetic encephalitis, characterized by a severe course.
- Epilepsy. The paroxysmal form of amnesia develops after an epileptic seizure with absences and large convulsive seizures. In this case, violations of higher mental functions are of a short-term nature.
- Neurointoxication. Memory disorders are observed when poisoning with chemical poisons, endogenous toxic metabolites (ammonia). Signs of pathology develop in disorders of water-electrolyte metabolism, endocrine diseases.
Pathogenesis
Memory is provided by all parts of the brain, although the memorization and reproduction of information has the most connections with the activity of the temporal lobes of the cortex. A significant role is played by the limbic system, prefrontal cortex, visual and auditory perceiving zones located in the occipital lobes. Retrograde amnesia can be caused by disorders in any of these zones, which explains the high prevalence of pathology in the practice of neurologists.
The physiological basis of memory is temporary neural connections that arise between cells under the influence of external stimuli. With long-term memorization, structural changes occur in nucleic acids, which explains the duration of information retention. Pathological processes in the brain disrupt all stages of memorization, but with retrograde amnesia, reproduction suffers the most.
Symptoms
In most of the victims, the disease affects recent life events. A person completely forgets everything that happened before the injury or neurological crisis. When such a patient comes to his senses, he is disoriented in time and space, often cannot tell his name and answer the simplest questions. The man asks how he ended up in the hospital and asks the medical staff to tell him what happened to him.
During an attack of retrograde amnesia, the mechanisms of recognition and fixation of new information are disrupted. A person can ask the same questions several times, is at a loss and is not able to take care of himself. If, after the onset of symptoms, the patient is not provided with medical care, he can randomly move around the city, ask incoherent questions to others in an attempt to orient himself.
After the elimination of the traumatic factor, memory begins to recover, although it does not return completely. Memories of the most vivid and emotional events of the amnesic period are the first to emerge, then additional details and new facts arise in the patient’s mind. With proper support from loved ones and constant communication, this process happens faster.
Complications
With retrograde amnesia, the consequences of the underlying disease that caused mental dysfunction come to the fore. With TBI, there is a risk of cerebral hemorrhage, swelling of the brain, and a comatose state. In the long-term period of any neurological diseases, paresis and paralysis, coordination disorders, speech and cognitive dysfunction are possible.
Retrograde amnesia presents difficulties from the point of view of the patient’s helplessness. While in the hospital, he can get up and walk without a doctor’s permission, get additional injuries from accidental falls, take out ivs and medical devices. Even more dangerous is the presence of a person with anamnestic disorders on the street, because he is prone to illogical actions and can harm himself.
Diagnostics
A primary role in determining retrograde anamnestic disorders is played by a clinical examination by a psychiatrist or neurologist. When interviewing a patient, they find out what period memory loss captures, assess the neurological status and the safety of other higher functions of the brain. To determine the root cause of the pathological syndrome, the following diagnostic methods are carried out:
- Neuroimaging. If a TBI or stroke is suspected, all patients are prescribed a CT scan of the brain, which reveals typical pathological foci. It is possible to clarify the damage to the nervous tissue with the help of MRI, which more accurately visualizes the ischemic zones.
- Electroencephalography. With the paroxysmal nature of the disease, it is necessary to exclude epilepsy, for which EEG recording is used. An EEG with stress tests and sleep deprivation allows us to assess the functional activity of the brain.
- Echoencephalography. The study reveals voluminous pathological processes in the brain, shows the position of the median brain structures. Echo-EG is informative for the diagnosis of edema and dropsy of the brain, cerebrospinal hypertension, hematomas and abscesses.
- Lumbar puncture. Invasive examination is required if meningitis is suspected. Analysis of the appearance, biochemical and microbiological parameters of the cerebrospinal fluid is necessary to confirm the diagnosis and isolation of the pathogenic pathogen.
Differential diagnosis
According to clinical and anamnestic data, retrograde disorders are differentiated with anterograde, congrade and total general amnesia. In typical cases, diagnosis is not difficult, but there are difficulties in determining the root cause of symptoms. Doctors of the emergency department and neurological hospitals carry out differential diagnostics of strokes and transient ischemic attacks, various forms of infectious and metabolic lesions of the central nervous system.
Treatment
Drug therapy
The basis of the treatment of amnesic disorders is the elimination of their root cause. Most patients in the first days of the disease are in the intensive care unit, where they receive etiopathogenetic drugs. For strokes, thrombolytic therapy, anticoagulants and antiplatelet agents are used. In infectious pathologies, antibacterial, antiviral, antifungal medications are indicated.
After stabilization of the condition, complex neurorehabilitation is carried out. It prevents the processes of secondary damage to nervous structures, promotes the restoration of mental functions, improves the prognosis for the patient. Several classes of neuroprotective drugs that affect different stages of biochemical disorders are recommended:
- Calcium channel blockers. Medications reduce the concentration of calcium ions in the intracellular space, prevent cellular apoptosis and fight excitotoxicity.
- Antioxidants. The drugs bind free radicals and reduce their synthesis, stimulate the activity of antioxidant defense enzymes, and increase the resistance of the brain to hypoxia.
- Anti-inflammatory drugs. To block immune and inflammatory reactions, COX-2 inhibitors, monoclonal antibodies that reduce the production of harmful cytokines are indicated.
- Nootropics. Medications improve higher mental activity, promote memory recovery, stimulate thinking and concentration of attention.
Psychocorrection
Correction of retrograde amnesia requires a multidisciplinary approach. In addition to drug therapy, individual psychotherapy is widely used. Classes with a psychologist are aimed at the gradual restoration of lost events, the elimination of concomitant problems caused by the underlying disease and mnestic disorders. Patients are taught techniques of autogenic training, relaxation techniques.
Prognosis and prevention
If retrograde amnesia captures a short period of time and is not accompanied by severe neuropsychiatric consequences, the prognosis is favorable. Gradually, the main events and skills of the anamnesis period are restored, the person returns to his usual life. In severe brain diseases, the prognosis is determined by the underlying pathology.
Prevention of amnesic syndrome consists in avoiding the causes that cause it. Medical and social work is being carried out to prevent domestic, road traffic and occupational injuries. Timely correction of dyslipidemia, cerebral atherosclerosis and arterial hypertension – the main factors of stroke development – is prescribed.