Pseudoneurologic syndromes: recognition and diagnosis

Author: Aziz Shaibani, Marwan N. Sabbagh
Date: May 15, 1998

When the mind-body relationship becomes unbalanced to the point -of a diseased state, the psyche can manifest several well-described disorders such as somatization disorder, conversion disorder, psychogenic pain disorder and factitious disorder. Perhaps the most common constellation of presenting symptoms and signs for these disorders are neurologic,[1] and they constitute the pseudoneurologic syndromes discussed in this review.

The nomenclature used to describe these conditions is confusing and overlapping. Terms such as "hysteria," "conversion," "functional," "nonorganic," "simulated" and "psychogenic" have been used interchangeably and are not dearly defined. For the purpose of discussion in this review, the terms "psychogenic" or "pseudoneurologic" will be used to refer to neurologic symptoms for which a psychologic etiology is suspected.

The significance of these conditions to the primary care physician cannot be overemphasized.[2]

From 25 to 72 percent of patient visits to primary care physicians are primarily the result of psychosocial distress presenting as somatic complaints.[3,4] Conservative estimates indicate that at least 10 percent of all medical services are provided for patients who have no evidence of organic disease.[5] Early diagnosis of pseudoneurologic syndrome spares the patient unnecessary, expensive and invasive procedures.

The economic impact of pseudoneurologic syndrome is tremendous. Patients with somatization have overall health care expenditures nine times that of unaffected persons, and over 82 percent of patients with somatization stop working because of their health problems.[3] This translates into a cost of $20 billion in health care expenditures annually, not counting time lost from work and disability payments.[6] Even a modest improvement in recognition and treatment of somatizing disorders could reduce health care costs significantly.

Pseudoneurologic Syndromes

The major pseudoneurologic syndromes are summarized in Table 1. The pseudoneurologic syndromes can mimic almost any organically based disease. A thorough history and neurologic examination are the most important aids to the clinician in distinguishing organically from psychologically based disease. Clues to the diagnosis of pseudoneurologic syndrome are outlined in Table 2. Although these dues do not rule out organically based disease, they should raise the clinician's suspicion for pseudoneurologic syndrome. In particular, objective findings such as normal reflexes, muscle tone and pupils are rarely altered by psychogenic causes, and pseudoneurologic syndrome often does not follow neuroanatomic (e.g., dermatomal) patterns.

TABLE 1

Pseudoneurologic Syndromes

Pseudoparalysis Pseudosensory syndromes (e.g., deafness, anesthesia) Psychogenic seizures Psychogenic movement disorders Pseudocoma Hysterical gait Pseudoneuro-ophthalmologic syndromes Hysterical aphonia

TABLE 2

Clues to Diagnosis of Pseudoneurologic Syndromes

Precipitated by stress Occurs or worsens in the presence of others Signs of other psychiatric illness (panic attacks, depression, schizophrenia) Histrionic personality History of multiple surgeries (e.g., appendix,

gallbladder, adhesion, nerve entrapment) No serious injuries sustained despite falls or "seizures" Denies psychologic etiology of symptoms Normal reflexes, muscle tone, pupillary reaction, etc. Symptoms persist despite specific medical treatment Alexithymia: inability to describe feelings in words Vague, bizarre, inconsistent description of symptoms by patient Striking inconsistencies on repeated examination Nonanatomic distribution of abnormalities

The psychiatric profile of patients with pseudoneurologic syndrome can be categorized using the classification of the somatoform disorders (somatization disorder, conversion disorder, psychogenic pain disorder, hypochondriasis and undifferentiated somatoform disorders) and factitious disorder given in the Diagnostic and Statistical Manual Of Mental Disorders (DSM-W).[7] Somatization disorder and conversion disorder are subconscious expressions of psychologic stress in the form of somatic complaints.[8] Like somatization disorder, conversion disorder is nonvolitional but presents with the sudden onset of single, usually nonpainful symptoms that are precipitated by stress. Symptoms occur mostly in adolescent or young adult women from socioeconomically deprived backgrounds.[8,9] Factitious disorder is a conscious fabrication of disease for personal gain.[10] Psychogenic pain syndromes (e.g., somatoform pain disorder)[11] will only be discussed in the context of other pseudoneurologic syndromes.

The spectrum of pseudoneurologic syndromes is broad. Table 3 lists the signs and symptoms of 405 patients with psychogenic dysfunction of the nervous system.[12] Pain and sensory symptoms were most common, and several patients had more than one psychogenic symptom.

TABLE 3Signs and Symptoms in 405 Patientswith Psychogenic Dysfunction of the NervousSystem NumberSign or symptom of patientsPain Trunk and extremities 89 Headache 61 Atypical facial pain 13Motor symptoms Astasia/abasia 52 Monoparesis 31 Hemiparesis 20 Tetraparesis 18 Paraparesis 10 Paresis of both arms 2 Recurrent head drop 1 Tremor 11 Localized jerking 1 Stereotyped motor behavior 1 Hypokinesia 1 Akinesia 1 Foot contracture 1 Isolated ataxia of the upper 1 extremitiesSensory symptoms Hypesthesia/anesthesia 81 Paresthesia/dysesthesia 83 Sensation of generalized vibration 1 Sensation of fever 1 Pressure in the ears 1 Deafness 1Seizures With motor phenomena 47 Other (amnestic episodes, 34 mental and emotional alterations) NumberSign or symptom of patientsVertigo/dizziness Attacks of phobic postural 47 vertigo Continuous dizziness 38Ocular symptoms Amblyopia 10 Amaurosis 6 Visual field defects 6 Color blindness 2 Double vision 2 Other visual phenomena 6 Ptosis 1 Convergence spasm 1 Unilateral gaze paresis 1Alimentary symptoms Dysphagia 4 Vomiting 4Speech disturbances Dysarthria 9 Slow speech 1 Aphonia 2 Mutism 1Neuropsychologic symptoms Cognitive impairment 2 Amnestic aphasia 1 Apathy 2 Coma 1Other symptoms Bladder dysfunction 1

Adapted with permission from Lempert T, Dietrich M, Huppert D, Brandt T. Psychogenic disorders in neurology: frequency and clinical spectrum. Acta Neurol Scand 1990;82:335-40.

Psychogenic disorders coexist with organic neurologic disease in up to 60 percent of patients and offer no immunity against any disease process.[13] Careful laboratory and radiologic investigation may be required to exclude an organic etiology. The following discussion illustrates the salient features of pseudoneurologic syndrome that may allow clinicians to differentiate organic from psychogenic: etiologies (Table 4).

Hysterical gaits can be dramatic, with patients lurching wildly in all directions, thus demonstrating a remarkable ability to do rapid postural adjustment. In contrast, patients with true paresis or paraplegia of the lower extremity tend to fall frequently. An unusual and illusive presentation of hysterical gait is known as astasia-abasia. In this condition, the patient is unable to turn or walk but retains normal use of the legs while lying in bed. However, atrophy of the vermis and frontal gait disorders (gait apraxia) can have similar presentations.[34]

Pseudoneuro-Ophthalmologic Syndromes

Pseudoneuro-ophthalmologic syndromes can mimic any pathology that affects the visual or oculomotor systems. The most common presentation of pseudoneuro-ophthalmologic syndrome is blindness.[35] Patients complain of sudden and complete loss of vision. Normal pupillary reaction and optic fundi exclude all organic causes, except cortical blindness, which is excluded by a normal optokinetic nystagmus response to horizontal or vertical movements of a striped drum. Alternatively, the clinician may place a mirror in front of a patient with pseudoblindness and gradually tilt the mirror from side to side. Humans reflexively tend to follow the reflection of their eyes or to look away from the mirror each time it is placed in front of them.

Another pseudoneuro-ophthalmologic presentation is tunnel vision,[35] where fields remain the same in inches at varying distances. In contrast, funnel vision (a physiologic condition) produces fields that expand in inches (but remain the same in degrees) proportionate to the distance viewed.

Diplopia is another pseudoneuro-ophthalmologic presentation.[35] True monocular diplopia (double vision with one eye covered) is very uncommon and indicative of pathology within the globe, such as retinal detachment or lens problems.[36] Nonorganic diplopia should be suspected in patients who present with monocular diplopia, especially if the ocular funduscopic examination is normal.[35]

The final pseudoneuro-ophthalmologic presentation is ptosis. Convincing voluntary ptosis can be achieved with practice. Ptosis is frequently a presenting symptom of conditions such as myasthenia gravis and chronic progressive external ophthalmoplegia. The diagnostic clue is the presence of ipsilateral eyebrow depression with pseudoptosis rather than the brow elevation that occurs with true ptosis.[35]

Hysterical Aphonia

Aphonia is defined as the absence of vocalization or phonation and differs from mutism, which is the absence of speech. Hysterical aphonia is characterized by a normal whisper and cough. Examination with a laryngoscope reveals normal vocal cord movement with respiration.

Final Comment

Pseudoneurologic syndromes occasionally occur, and primary care physicians should be familiar with them. A careful history and physical examination give the best clues to an accurate diagnosis, which can save time and money by avoiding exhaustive and expensive investigations and prevent suffering caused by invasive procedures.

Patients with pseudoneurologic syndromes deserve the same compassionate treatment as any other patient. They are behaving in what seems to be the only cultural and situational manner appropriate for them. They should never be ridiculed. Rather, they should be given the support, time and encouragement needed to return to normal function. Consultation with a psychiatrist or psychologist is often helpful, since these patients typically have emotional issues to deal with even after the pseudoneurologic syndrome resolves.

The authors thank Barbara Reader for technical assistance and Mark Kritchevsky, M.D., and Marjorie Seybold, M. D., for editorial advice in the preparation of the manuscript.

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AZIZ SHAIBANI, M.D., is director of neurology at Houston (Tex.) Neurocare. He received his medical degree from Mosul University, Mosul, Iraq. Dr. Shaibani completed a medical internship at Conemaugh Valley Memorial Hospital, Johnstown, Pa., as well as a residency in neurology and a fellowship in neuromuscular diseases at Baylor College of Medicine, Houston.

MARWAN N. SABBAGH, M.D., is assistant professor of neurosciences at the University of California, San Diego, School of Medicine. He received his medical degree from the University of Arizona College of Medicine, Tucson, He completed a medical internship at the Good Samaritan Regional Medical Center in Phoenix, a residency in neurology at Baylor College of Medicine and a fellowship in geroneuropsychiatry and dementia at the University of California, San Diego, School of Medicine.

Address correspondence to Marwan N. Sabbagh, M.D., Department of Neurology (9127), San Diego Veterans Affairs Medical Center, 3350 La Jolla Village Dr, San Diego, CA 92161. Reprints are not available from the authors.

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