A research study shows how common a medical misdiagnosis can be and how severely it can exacerbate a disease.

Focusing on a rare, genetic and disabling disease known as fibrodysplasia ossificans progressiva, or FOP, researchers designed the study as an examination of the frequency of misdiagnosis and the complications associated with it.

Their findings are reported in the journal Pediatrics.

Fibrodysplasia ossificans progressiva is a disorder of connective tissue that ultimately results in massive bone formation across the body's major joints, eventually rendering movement impossible. The disorder affects one in two million people worldwide, and there are 200 known cases in the U.S.

The study found that fibrodysplasia ossificans progressiva is misdiagnosed 87 percent of the time, takes an average of four years to be accurately diagnosed, and often is inaccurately identified as cancer. The inaccurate diagnoses have led to painful biopsies and incorrect treatments that in themselves often worsened the condition of the patient, speeding permanent loss of mobility.

" It is unfortunate that individuals afflicted with this rare disabling disease have suffered further serious problems due to incorrect diagnoses by their physicians," said Joseph Kitterman, lead investigator and at the University of California, San Francisco.

Based on study findings, the researchers estimate that only 10 percent of doctors have ever heard of fibrodysplasia ossificans progressiva. Only eight percent of the 184 medical textbooks that they reviewed contained adequate descriptions of fibrodysplasia ossificans progressiva.

An accurate diagnosis of the disease can be made based on the clinical findings of tumor-like swellings on the head, neck, back or shoulders in association with malformations of the great toes, according to Kitterman. However, the study showed that physicians often misdiagnosed the condition because the patient was not fully examined or the physician was not aware of fibrodysplasia ossificans progressiva.

The disease is distinguished by the unique characteristics of toe malformations and missing joints which are present at birth, but their significance is almost never appreciated, Kitterman noted.

" The irony here is that diagnosis of fibrodysplasia ossificans progressiva has distinguishing features and is obvious just by asking a few simple questions," he said. " Instead, with misdiagnosis of this rare disease, the result was anxiety and pain for the patient."

The study found that patients often endured painful deep muscle biopsies and permanent complications due to misdiagnosis, with almost half reporting permanent loss of mobility that resulted from invasive procedures.

No condition other than fibrodysplasia ossificans progressiva is associated with malformed toes and rapid tissue swellings during childhood, Kitterman said.

" Fibrodysplasia ossificans progressiva can look like cancer. Inspection of the toes, however, would instantly reveal a different disease," said co-investigator Frederick Kaplan, at the University of Pennsylvania.

" The disease is easy to diagnose once the physician knows what to look for," he added.

The study findings showed that it took an average of six physicians to accurately diagnose fibrodysplasia ossificans progressiva. Those consulted most frequently were orthopedic surgeons, pediatricians, general practitioners, oncologists, rheumatologists and internists.

The research team reviewed the experiences of 138 patients with fibrodysplasia ossificans progressiva from around the world. The extremely high rate of misdiagnoses was worldwide, with cancer cited most often. Sixty-seven percent of the study patients had unnecessary invasive procedures, and 68 percent received inappropriate therapies.

The next steps in finding a cure for fibrodysplasia ossificans progressiva are to define the metabolic pathways that influence the disease and identify the gene that causes it, according to the researchers.

Source: University of California - San Francisco, 2005


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