posttraumatic amnesia

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posttraumatic amnesia

Abbreviation: PTA
A state of agitation, confusion, and memory loss that the patient with traumatic brain injury (TBI) enters soon after the injury or on awakening from coma. Edema, hemorrhage, contusions, shearing of axons, and metabolic disturbances impair the ability of the brain to process information accurately, resulting in unusual behaviors that are often difficult to manage. Trauma patients with normal brain scans may have mild TBI and display some of the symptoms of PTA. Posttraumatic amnesia can last for months but usually resolves within a few weeks. During PTA, the patient moves from a cognitive level of internal confusion to a level of confusion about the environment. See: Rancho Los Amigos Guide to Cognitive Levels


Symptoms include restlessness, moaning or crying out, uninhibited behavior (often sexual or angry), hallucinations (often paranoid), lack of continuous memory, confabulation, combative behavior, confused language, disorientation, perseveration, and sleep disturbances. Problem-solving ability, reasoning, and carrying out planned motor movements (as in activities of daily living) may also be impaired.

Patient care

The patient is continually reoriented by a large calendar and clock within sight; each interaction with the patient begins with a repetition of who is in attendance, why the attendant is present, and what activity is planned; and the patient is kept safe and comfortable and is allowed as much freedom of movement as possible.

As the patient becomes confused, he may show agitation. Health care professionals can limit agitation and confusion by speaking softly in simple phrases, using gestures as necessary, and allowing time for the patient to respond. Regular visits from family are important; the family should be prepared for the patient's appearance and behavior; they should be encouraged to help the patient with activities of daily living.

Equipment for agitated patients is used; wrist restraints are avoided if possible. Urinary catheters may increase agitation due to physical discomfort (incontinence briefs can be used during the training period of a toileting program). The patient's swallowing function is evaluated as soon as possible to avoid feeding tubes, but swallowing precautions are observed. A list of stimulations that increase or decrease the patient's agitation is posted for the use of everyone in contact with the patient. Distance is maintained during aggressive outbursts. The patient's personal space should not be invaded without warning (e.g., the patient should be told in advance that his body parts are going to be touched or washed). The patient should be approached from the front, and items should be placed where the patient can best see them.

Health care professionals should watch closely for impulsive movement that can jeopardize the patient. They should warn others that the patient cannot monitor his own behavior and that words and actions may occur without awareness or forethought. Independent behavior and self-care are encouraged. The patient is engaged in short activities with a motor component. One action at a time should be monitored if the patient performs several actions that interfere with treatment. To promote abstract reasoning, humor should be used if the patient understands it. A consistent daily schedule provides structure. The patient is taught to use compensatory cues (a watch or written activity schedule) to aid memory. The patient is also assessed for posttraumatic headache, which is treated with prescribed medications.

See also: amnesia
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
The criteria for mild TBI were that for each episode of TBI the duration of loss of consciousness was less than 30 minutes, the duration of any alteration in mental state (e.g., confusion, disorientation, slowed thinking) following the TBI was less than 24 hours, and the period of any posttraumatic amnesia was less than 24 hours.
The mean length of posttraumatic amnesia (PTA) was assessed prospectively using the Galveston Orientation and Amnesia Test (GOAT) [28] by neuropsychologists.
According to the Department of Veterans Affairs (2004), levels of severity are defined by using one of three indexes: the Glasgow Coma Scale (GCS), length of loss of consciousness (LOC), and length of posttraumatic amnesia (PTA).
TBI involves a postconcussional syndrome that includes: (1) a period of unconsciousness lasting for more than 5 minutes after the brain trauma, (2) a period of posttraumatic amnesia lasting for more than 12 hours, and (3) a new onset of seizures that occurs within the first 6 months after the injury (American Psychiatric Association, 1994).
Although there is insufficient evidence to establish a definite threshold for the severity of the closed head injury, specific criteria have been suggested, for example, two of the following: (1) a period of unconsciousness lasting more than 5 minutes, (2) a period of posttraumatic amnesia that lasts more than 12 hours after the closed-head injury, or (3) a new onset of seizures (or marked worsening of a pre-existing seizure disorder that occurs in the 6 months after closed head injury.(12)
Severe and moderate TBI were the only exclusion criteria and were defined as more than 30 min in coma, brain bleeding or blood clot (abnormal brain computed tomography scan), or none of first 24 or more hours after event remembered (posttraumatic amnesia [PTA] > 24 h).
The patients had recently sustained a head trauma and were diagnosed with an mTBI by a physician who used WHO Task Force Criteria [15], which includes at least one of the following symptoms: posttraumatic amnesia of less than 24 hours, loss of consciousness of up to 30 minutes, seizure, focal signs, disorientation, or scans demonstrating intracranial lesions that do not require surgery.
Currently, duration of unconsciousness and posttraumatic amnesia are also considered in determining TBI severity.
In the civilian sector, the best validated tool is the Westmead Posttraumatic Amnesia Scale (9) (Figure 1), but the military now uses the Military Acute Concussion Evaluation (10) (MACE) (Figure 2).
Length of coma and/or posttraumatic amnesia (PTA) is used to define the duration of the dysfunction.
Richard suffered weeks of posttraumatic amnesia, which saw him order cottage pie each day in hospital then greet it with surprise.
Also, patients with posttraumatic amnesia of any duration were 4 times more likely to have a poor outcome than a good outcome.

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