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CONVERSION REACTION |
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In
the late 1880s, Sigmund Freud, described conversion reaction as the
manifestation of a repressed internal emotional conflict into an externalized
physiological form.
According to the DSM IV, conversion disorders
are characterized by the following:
1) unexplained symptoms affecting voluntary motor or
sensory function in ways that suggest, yet are not fully explained by a
neurological or other general medical condition, and
2) the presence
of psychologic conflicts that play a significant role in initiating, exacerbating, and
maintaining the disturbance.
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Above: Famous French neurologist, Charcot
examining a woman suffering from "hysteria." The term hysteria is considered
pejorative and no longer used. Instead the terms conversion reaction, functional
disorder and somatoform disorder are generally used. Charcot saw patients who
where blind, paralyzed, or who had some other physical symptom that under
hypnosis, the abnormality would disappear. He inferred that the underlying
problem was psychologic and not organic.
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Conversion disorders and malingering are not the same! They lie on opposite ends
of a spectrum of intentionality. Psychiatrically speaking, malingering is
conscious and produces identifiable external gain, known as “secondary gain.”
The secondary gain may be to obtain disability or litigation awards, or skip out
on work. The malingering patient is actively and knowingly trying to fool the
examiner.
A conversion disorder is strictly subconscious and
is considered to be a manifestation of subconscious psychological distress.
The gain is mainly primary gain, in that the main reason for the observed
neurological dysfunction is an externalization of an inner subconscious
psychological conflict. However, even in conversion disorder, some secondary
gain may be present in that avoidance of an unpleasant situation, as well as
attention by family, friends or care providers brought by the illness may be
desired by the patient. The subconscious nature of conversion disorder, along
with lack of clear motives, makes the identification of conversion disorder more
challenging to neurologists than that of malingering patients.
A few general points are useful to keep in mind during the history of
patients with potentially psychogenic neurological dysfunction. First,
ill-defined or inconsistently described symptoms may raise a red flag, as should
a pattern of chronic, changing complaints. Also, a pattern of family psychiatric
disorders, substance abuse or illness may be correlated with non-organic
symptoms, and certainly substance abuse or a history of mental illness in the
patient may be suggestive. Finally, correlating the symptoms with social
stressors or anxiety-inducing events may be illustrative.
Clearly, organic causes of symptoms need to be ruled
out before a psychiatric diagnosis is made, however there are a
number of history and physical exam techniques that may provide guidance. This
can help reduce expensive and potentially risky diagnostic tests.
A first step to help confirm the diagnosis of conversion disorder may be to
categorize the neurological dysfunction into motor,
sensory or movement
disorders. Movement disorders may include: psychogenic tremors,
choreic movements, dystonia or pseudoseizures. By this distinction, one can
systematically examine techniques that may guide selection of appropriate
diagnostic testing and therapy.
Motor disturbances often take the form of
hemiparetic and/or gait disturbances which may be represented as ataxia,
trembling, or buckling of the knees. Several signs may indicate a psychogenic
etiology. The most suggestive of both of psychogenic gait disturbances and of
other manifestations of conversion disorders, is inconsistency of presentation
among different examinations and with distraction of the patient. Other features
include bizarre gait patterns, especially tandem walking with excessive arm
waving and body swaying. The patient may demonstrate an inability to stand or
walk, despite perfectly normal neurological exam while in bed, including
sensory, propioceptive and cerebellar function. This gait is termed
"astasia-abasia." It is important to consider
midline cerebellar disease as an organic cause of gait disturbance, as this may
not be readily detectible during the bedside exam.
As far as identifying psychogenic weakness or paralysis, the most objective
aspect of the examination are the reflexes and muscle tone, over which the
patient has little control. In testing strength to confrontation, the examiner
will frequently find that the psychogenic patient exhibits initial strength
followed by a "give-way quality".
Furthermore, it may be possible to determine a psychogenic etiology by
proceeding quickly from proximally to distally in the extremities. In this
manner, the patient may not be able to think about which extremity is supposed
to be weak, and it is possible to find that the limbs will give away bilaterally
or not at all. This test is probably more useful in the malingering patient than
the patient with true conversion disorder.
Another
useful test, Hoover’s sign, described in
1908 by Charles Franklin Hoover, an American physician born in Cleveland, Ohio,
may help differentiate between organic versus psychogenic weakness. The patient
is asked to raise their paretic leg off of the bed against examiner’s
resistance, while the examiner holds a hand under the opposite heel. A normal
individual with or without hemiparesis will involuntarily contract the
contralateral hip extensor, thus forcing down the contralateral heel in
proportion to the upward force of the ipsilateral leg. However, a patient with a
psychogenic weakness will not push down and may even lessen pressure on the
“good” heel when asked to raise the “paretic” leg. This lack of reflexic,
involuntary response, is due to poor effort, rather than true weakness, as in
true weakness there should still be some degree of contralateral hip extension.
This phenomenon is based on the principal of synergistic contraction described
by Charles Sherrington in the 1890s in which contraction of one set of muscles
(flexor or extensor) results in reflexic contraction of the opposite set of
corresponding muscles (for those interested, in the history of Hoover's sign,
click here).
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The maneuver can be reversed (reverse Hoover’s
sign) in the case of complete hemiplegia. The examiner places a hand
under the heel of the hemiplegic leg and asks the patient to lift the
contralateral normal leg. During straight leg elevation, the contralateral hip
extensor will contract in a psychogenic patient, which can be perceived by the
examiner. A truly hemiplegic limb should not contract by movement of the
contralateral limb. It needs to be emphasized that this maneuver is only helpful
if the leg is hemiplegic, not hemiparetic.
In addition, if a truly paralyzed arm is placed above a patient's face and
dropped, it fall directly on the patient's face. In psychogenic weakness, the
arm will pull away from the face as it is dropped, to avoid striking the face.
Again, this is only valid if the arm is completely plegic.
Often, in psychogenic weakness, the patient will display profound weakness
with formal confrontational testing; but will be able to perform informal or
functional tasks without obvious difficulty (e.g., a patient may have profound
hip weakness on exam; but can get up to the examining table without difficulty)
Another test that can be helpful in differentiating psychogenic from organic
weakness due to corticospinal tract involvement is pronator drift. This is
performed by having the patient hold both arms out in front of them, fully
extended in a supinated position. In a patient with organic disease the affected
limb will pronate gradually, while the normal limb will remain supinated. This
is due to selective weakness of the forearm supinator as compared to the
pronator in corticospinal tract damage. In a psychogenic patient asked to do
this test, the “paretic” limb will usually fall straight down without pronating.
The following chart helps to summarize useful tools in differentiating
psychogenic from organic weakness. Some of the tests are specifically designed
for a corticospinal tract related weakness, whereas others are for all types of
organic weakness. Note, that there is not one test that can help decide
definitely if the weakness is organic or psychogenic, but rather it is the
overall picture which is important. |
HEMIPARESIS |
Psychogenic |
Organic |
Tone |
symmetric |
usually asymmetric |
Reflexes
(DTRs and babinski sign) |
symmetric |
usually asymmetric |
Hoover’s sign |
present |
absent |
Give-away weakness |
present |
absent |
Extensors vs flexors (corticospinal
tract) |
usually no difference |
flexors may be stronger than extensors
in corticospinal tract lesions |
Proximal vs distal (corticospinal
tract) |
usually no difference |
a distal to proximal gradient |
Inconsistencies of strength
(during formal exam versus informal observations) |
frequent |
rare |
Sternocleidomastoid muscle |
weak turning toward paretic side |
weak turning away from paretic side or
normal. |
Pronator drift test (corticospinal
tract) |
negative (lowering of weak limb, without
pronation) |
positive (pronation of weak limb) |
Gait |
drags paretic leg |
circumducts leg |
Arm drop above head
(in plegic arm) |
moves limb away from face |
limb hits face |
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Sensory disturbances are difficult to
differentiate between psychogenic versus organic due to the inherently
subjective nature of sensation. Nevertheless, there still exist helpful
differentiating features. With non-organic sensory disturbance, the exam is
inconsistent from examination to examination and also with distraction. An
additional frequently referenced clue is that there is a non-physiological
pattern of sensory abnormality. This means that the sensory disturbance is not
in a cortical, dermatomal or peripheral nerve distribution. These may include:
sharp demarcation of sensory change at the body midline, or a pattern of
sensation disturbance that conforms with body parts. For instance, a patient may
complain of anesthesia from the shoulder on down with a circumferential line of
sensory loss that does not fit an organic sensory loss pattern. Or, the patient
may have an apparent sensory level on the anterior chest that differs greatly
from the sensory level on the back.
Methods to be used during the exam may include noting the timing of a
patient’s “no” response when testing sensation with the eyes closed. It is
suspect if the patient consistently says “no” to feeling sensation if spoken
right at the instant of stimulation. |
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The zigzag test may be helpful. The
patient’s eyes are closed and the border of sensory loss is marked. Then the
examiner tests sensation for the normal sensory region, approaching that line in
a zigzag fashion. In psychogenic sensory disturbances, the border will move
toward the region of normal sensation and will continue to move into that region
with repeated testing. |
Psychogenic movement disturbances, may
take the form of tremor, chorea, dystonia or other abnormal postures or
movements. Pseudoseizures are among the most
common of the psychogenic movement disorders. Unlike true seizures,
pseudoseizures are often “less stereotyped.” This means that an inconsistent
appearance from one episode to another occurs. Pseudoseizure may be triggered by
an emotional event, whereas an epileptic seizure has variable or no specific
trigger. Pseudoseizures are usually more gradual in evolution and longer in
duration than epileptic seizures. Evolution of seizure refers to changes in the
seizure manifestation from onset to the end of the seizure. Pseudoseizures may
consist of side-to-side head movements, pelvic thrusting and random asynchronous
movements, whereas real seizures are usually less limited in there array of
movements. It is important to know that frontal lobe epilepsy may manifest with
bizarre and varied movements that resemble a pseudoseizure. Patients with
pseudoseizure are unlikely to injure themselves during the seizure, have tongue
biting or urinary incontinence, whereas these are common after a generalized
tonic-clonic seizure. The difficulty in diagnosing pseudoseizures stems from the
knowledge that a high proportion of pseudoseizures occur among patients with
true epilepsy. Patients that have history of psychiatric illness and especially
sexual abuse have a higher incidence of developing pseudoseizures. . Additional
physical findings that may suggest pseudoseizure rather than epileptic seizures
is a retained ability to follow commands or talk during an event. However, a
very focal partial seizure may not completely impair an ability to follow
commands or talk.
Video EEG is the most useful diagnostic tool in differentiating true seizures
from pseudoseizures by showing no electrographic seizures or epileptiform
activity during a period of apparent seizure.
The table below summarizes the main differences between a pseudoseizure and
true seizure. |
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Pseudoseizure |
True seizure |
Precipitant |
emotional trigger common |
variable or none |
Stereotyped |
no |
usually |
Evolution |
gradual |
quick |
Length |
may last hours |
usually seconds to minutes (except status epilepticus) |
Consciousness |
usually maintained |
usually impaired |
Witnessed |
almost always |
variable |
Psychiatric history |
frequent |
uncommon |
Tongue biting, urination and injury |
rare |
common |
EEG findings |
no electrographic seizure activity. |
usually electrographic seizure activity. |
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Ultimately, conversion disorder is a difficult diagnosis to make. Objective
laboratory and imaging techniques are needed to exclude organic disease.
A diagnosis of conversion reaction should always be made with caution.
It is an error for physicians to dismiss unexplained symptoms as a conversion
reaction. Often, they are wrong. Nearly all patients with conversion reaction
have a past history of hypochondriasis or psychophysiologic reactions (often the
hyperventilation syndrome). All symptoms need to be evaluated to exclude organic
etiologies.
The other danger is that is easy to
dismiss a patient's complaints after an inconsistent feature is seen,
especially if some secondary gain is obvious. However, it is not uncommon that a
patient has a true organic underlying condition, but also has a functional overlay,
where they may exaggerate an otherwise subtle clinical
finding. |
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