eMedicine Specialties > Psychiatry > Psychosomatic

Munchausen Syndrome: Differential Diagnoses & Workup

Author: James C Hamilton, PhD, Associate Professor, Coordinator of Clinical Health Psychology, Department of Psychology, Clinical Affiliate Associate Professor of Internal Medicine, University of Alabama
Coauthor(s): Marc D Feldman, MD, Clinical Professor of Psychiatry, Department of Psychiatry and Behavioral Medicine, and Adjunct Professor, Department of Psychology, University of Alabama, Tuscaloosa, AL
Contributor Information and Disclosures

Updated: Sep 16, 2009

Differential Diagnoses

Conversion Disorders
Hypochondriasis
Malingering
Somatoform Disorders

Other Problems to Be Considered

Differential medical diagnoses

The initial presentation of patients with factitious disorder or Munchausen syndrome always suggests a medical or psychiatric problem, with features compatible with the ailment being feigned or produced. The ruses are limited only by the patient's creativity, knowledge, and motivation and can include esoteric diagnoses about which most doctors would be largely unaware.

Factitious disorder should be excluded when routine examination and testing fail to confirm any of the most obvious diagnostic possibilities. At this juncture, clinicians should consider among their differential diagnoses idiopathic medical illnesses that have a fluctuating course or that manifest across several different organ systems (eg, multiple sclerosis, systemic lupus erythematosus). The case literature suggests that the most frequent medical diagnoses among patients who are falsely believed to have factitious disorder or conversion disorder are central nervous system diseases (eg, encephalopathy), metabolic diseases, and structural diseases of the muscles and connective tissue.

When creating a working list of hypotheses for the diagnosis of a puzzling medical case, it is important to follow base-rate information about the frequency of each diagnostic possibility. If this procedure were followed, factitious disorder or Munchausen syndrome would probably emerge as the third-to-fifth most likely diagnosis in such cases. Even if factitious disorder occurs only once per 10,000 patients (probably an underestimate), it would still be more prevalent than some of the exceptionally rare disorders that a physician might consider before entertaining the possibility that the patient is feigning illness. Cases abound in which doctors have bypassed consideration of factitious disorder as they repeatedly performed yet more tests, medication trials, and/or surgeries or applied literally novel diagnoses.

Differential psychiatric diagnoses

Factitious disorder and Munchausen syndrome must be distinguished from two related types of clinical problems.

The first of these is simple malingering. When a discernible primary external motive for the deceptive illness behavior exists, the label of malingering is applied. Examples of external goals are acquiring narcotics, evading criminal prosecution, gaining disability payments, and avoiding military service. Unlike the others, malingering is not an official mental disorder, though it can sometimes be a focus of clinical attention.

In practice, this determination almost always requires a weighing of internal and external incentives because the sick role itself almost always includes rewards and dispensations of various kinds (eg, financial assistance that a church insists the patient accept). The external goal in malingering is usually obtained by first securing a physician's official confirmation of an authentic illness or injury. The malingering patient will abide only as much testing and treatment as necessary to achieve this aim. In contrast, persons with Munchausen syndrome actively attempt to maintain the sick role and willingly undergo as much testing and treatment as possible.

The second vital differential is hypochondriasis. In a typical case of hypochondriasis, the patient presents with anxiety, and either no physical signs are present and objective test findings are within normal limits, or a medically insignificant sign is noted (eg, discoloration of the skin). The patient may insist with true conviction that he or she is gravely ill and demand various tests. When the results of the tests are negative, the patient is typically relieved, at least for a short time.

This presentation is not easily confused with factitious disorder or Munchausen syndrome; however, in rare instances, the patient's conviction that he or she is gravely ill may be so strong that the patient resorts to simulation or self-injury as a means of soliciting further diagnostic testing. The differential diagnosis may thus depend on subtle signs such as the presence or absence of relief when the patient is informed of negative test results and the patient's willingness to permit caregivers to communicate with each other and with family members.

According to the DSM-IV-TR, factitious disorder and Munchausen syndrome must also be distinguished from the other somatoform disorders, particularly somatization disorder, conversion disorder, and pain disorder. The DSM-IV-TR assumes these disorders represent a completely distinct category of psychiatric disorders and are distinguished from factitious disorder by the belief that patients with somatoform disorders do not intentionally exaggerate or feign illness: Complaints in somatoform disorder are presumed to be generated through unconscious processes. In practice, it may be impossible to distinguish between somatoform disorders and factitious disorder in patients who do not carry out physical simulations or self-injury that might provide concrete evidence of intentional deception.

Workup

Laboratory Studies

• The medical assessment of patients with chronic factitious disorder is analogous to the task of piloting an airplane through dense clouds. Under those flying conditions, it is important for pilots to follow the basic rules of flying and to trust their navigational instruments. Pilots who depart from these procedures and rely instead on their own inner sense of direction and orientation are at risk for a bad—if not disastrous—outcome. Similarly, physicians who encounter patients they cannot diagnose and who do not respond to the usual treatments can experience a similar feeling of panic and disorientation.
  • When this occurs, the physician should (1) follow the basic procedures for responding to the patient's signs and symptoms, (2) trust the reliability and validity of the medical tests that he or she performs, and (3) respect base-rate information about the prevalence of various diseases that must be excluded. Cases abound in which tests have been needlessly repeated, invasive procedures performed without adequate justification, or medications prescribed with such apparent zeal that iatrogenic problems actually come to dominate the clinical picture.
  • Patients with Munchausen syndrome use several techniques to disrupt the physician's usual practices. Typically, they exploit the clinician's fear of overlooking a rare, life-threatening disease. Simultaneously, they play to the clinician's fascination with rare and inscrutable medical problems. The patient with Munchausen syndrome understands the appeal of a medical mystery and the personal satisfaction, notoriety, and esteem that the physician experiences when he or she solves one. These factors combine to cause the physician to depart from standard procedures and to overlook more benign explanations for the patient's signs and symptoms.
  • Paradoxically, patients with Munchausen syndrome can also disrupt the physician's usual practices by persuading the physician to forego basic diagnostic procedures. Striking evidence of this phenomenon is noted in reports of patients who have successfully feigned diseases such as AIDS with Kaposi sarcoma and malignancies such as breast cancer. In both of these real-life examples, definitive tests were available to establish the presence of these diseases, but they were not performed because the patients' persuasive but false medical history, perhaps combined with their physical appearance, led to the mistaken assumption that the tests were unnecessary. Doctors may also erroneously believe that the ailment under consideration could not possibly be feigned or self-induced.
• Laboratory tests may be particularly helpful in identifying patients with Munchausen syndrome. Because many of these patients have a medical background, they often know the routine tests performed for a particular symptom presentation.
  • For example, a patient with anemia would anticipate that routine blood work would not include screens for the anticoagulants he or she has ingested, thus prolonging the medical or surgical investigation as the professionals search for the elusive etiology, such as unexplained hematuria or hematochezia.
  • The number of other ways in which patients have used tests and test results to mislead doctors is staggering. Several examples illustrate the range. Patients commonly self-inject insulin to create a baffling, tenacious, and dangerous hypoglycemic state. Before a diagnosis of insulinoma is made, doctors can expose the ruse by assessing whether or not the C-peptide level is compatible with the insulin level. High insulin levels combined with low C-peptide levels indicate factitious hypoglycemia.
  • Patients can create alarming laboratory evidence of proteinuria simply by adding a drop of egg white (a pure protein) to their urine specimens. A small amount of blood, perhaps added to a stool specimen or swallowed prior to endoscopy, appears as conclusive evidence for gastrointestinal pathology. The presence of unexplained puncture sites, especially in odd areas (eg, base of the tongue) can provide very compelling evidence of such dissimulation.
  • Conversely, laboratory test results may be inconsistent with the claimed illness, such as a lack of an elevated WBC count or left shift in an apparent case of sepsis or necrotizing fasciitis. Bacterial cultures may grow an overly wide variety of enteric flora when taken from infected sites distant from the pelvic or groin area because the patient has contaminated the wound with feces. Intractable diarrhea or vomiting may be missed unless the physician specifically asks laboratory personnel to assess for agents such as phenolphthalein or ipecac.
  • Some patients enter the nurses' station or access the vital-sign clipboards outside their doors and directly change laboratory values from normal to abnormal. They may present the doctor with letters from colleagues purporting to verify laboratory pathology, but a follow-up call reveals that the letterhead paper was stolen and a worrisome report was typed by the patient. Of course, self-induced but real illnesses (eg, extreme lead poisoning created by drinking water in which lead-based items were boiled) show corresponding authentic laboratory analyses that compel emergency treatment.

Imaging Studies

Imaging studies may be useful in diagnosing Munchausen syndrome. They may be particularly useful in cases in which the patient presents with a well-established medical problem of the type that can be easily imaged (eg, inoperable malignancies, cardiovascular accidents). In these cases, errors are made by eschewing these tests to spare the patient the expense or inconvenience of repeating tests that have already returned positive indications of disease. For many patients with Munchausen syndrome, the use of imaging studies becomes part of the search for an explanation for their puzzling signs and symptoms.

Procedures

• Medical personnel should base testing on a well-considered and prioritized differential diagnosis. The performance of any procedures should be approached very conservatively if suspicions arise (eg, the patient has the "road-map" abdomen caused by scars from prior exploratory operations). Tests should not be needlessly repeated in the misguided hope that diagnostic pathology will suddenly emerge.
• Strongly subjective tests, such as electromyelography and nerve conduction velocity tests, should be understood as almost never definitive in isolation. An occasional positive finding, likely whenever anyone is subjected to extremely extensive and repeated testing, should not be misinterpreted. Clinicians should remember that each intervention poses a risk of iatrogenic complications that only complicate the picture. Indeed, such complications have frequently led to malpractice actions against physicians.

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