By Ed Susman
AUSTIN, TX—Errors in judgement and diagnostic biases may lead to delays in diagnosis and misdiagnoses of amyotrophic lateral sclerosis (ALS), according to a report presented here at the annual meeting of the American Association of Neuromuscular & Electrodiagnostic Medicine.
The report sought to analyze how different strategies clinicians use to make medical judgements and decisions—referred to as "heuristics"— may lead to missed or inaccurate diagnoses of ALS. They found certain heuristics were more common for veterans with ALS than for non-veterans with the disorder.
"What we did with this study was to determine why there were misdiagnoses and what we can do to correct those errors from occurring," the senior study author Raghav Govindarajan, MD, told Neurology Today At the Meetings.
"One thing we can do in training physicians is to teach them about how these heuristic errors can occur," said Dr. Govindarajan, associate professor of neurology at the University of Missouri. "It is not enough to teach students how to diagnose, but to teach them how it is possible to misdiagnose, and why that happens. It should be at the forefront of the curriculum for students as well as long-time practitioners like me."
For the study, Catherine Rodriguez, a medical student at the University of Missouri, and colleagues reviewed electronic medical records and the treatment course of 88 ALS patients seen at the University of Missouri Hospital in Columbia from 2011 to 2017. They collected demographic information and clinical characteristics of their ALS. If the patient received an incorrect diagnosis, the researchers recorded the number of physicians seen, the type of diagnostic error, clinical factors contributing to the misdiagnosis, and the type of physician who gave the incorrect diagnosis.
The study found that veterans were more often misdiagnosed due to the "availability" heuristic, while non-veterans were misdiagnosed due to the "anchoring" heuristic (p< 0.05).
"When you see a patient such as a veteran and you have experiences with other veterans who tend to have certain characteristics and complaints, you may think that the patient in front of you fits into that same mold—this is known as the availability heuristic," Dr. Govindarajan explained.
The anchoring heuristic refers to the human tendency to accept and rely on the first piece of information received before making a decision, he said. That first piece of information is the anchor and sets the tone for everything that follows.
In the anchoring heuristic, Dr. Govindarajan said, a patient may come to the emergency department with a cough and a cold and because the physician has seen a lot of patients with influenza, he or she determines that this is another case of influenza.
"We expected that anchoring and availability heuristic errors would be equal between veterans and non-veterans, but we didn't see that," Dr. Govindarajan said.
Dr. Govindarajan cited another example. "I had a patient who had complained that he was getting weak and that he was falling, and he had a history in the past of alcohol use. The person who had been treating him [and referred him to me] diagnosed his problem as neuropathy due to alcohol use," Dr. Govindarajan said. "But when things got worse we found out that he had ALS."
"This kind of availability heuristic leads to a delay in diagnosis and treatment," he said, "and in a lot of patients, they may undergo unnecessary treatment, even surgery. It delays the patients from reaching specialized ALS multidisciplinary clinics, which studies have shown can lead to better outcomes—a better quality of life."
"Lower limb onset was most commonly misdiagnosed due to the anchoring heuristic (p< 0.05)," Rodriguez reported in the study abstract. "Bulbar onset was most commonly misdiagnosed due to the availability heuristic (p< 0.05), and surgical intervention was the most common treatment for an incorrect diagnosis (p< 0.05).
"Absence of upper motor neuron signs on examination, presence of sensory symptoms, and absence of tongue fasciculations are common causes of ALS misdiagnosis," Rodriguez reported.
Commenting on the study, Scott M. Friedenberg, MD, director of the ALS Clinic at Geisinger Medical Center in Danville, PA, said ALS can be very challenging to diagnose as it is "incredibly rare, and there are many things that mimic it."
He noted that in the current study, there were 88 patients in seven years, which amounted to approximately one patient a month.
He pointed out that diabetes is common as is trauma among veterans—so a doctor might leap to thinking that these patients have a complication of diabetes or back injury, and may not immediately recognize the neuromuscular nature of the disease.
"With the veterans, you consider that you have seen a lot of diabetics that have nerve problems, and you are looking at a veteran who is diabetic, so you go down that road," he said.
"For the non-veterans, the physician may be grabbing for a specific feature that has been logged in their memory and associated with that individual patient," he said.
"What is happening in both cases is that the physician is not able to take a step back and see the whole picture," Dr. Friedenberg said. "In order to reach a diagnosis of ALS you have to have a broad picture of the patients."
Dr. Friedenberg said that neurologists who eventually have patients with ALS referred to them should go back to the referring physician to discuss the case, in hopes of educating them as to what they saw in the patients and to ask what the referring physician saw. "We hope to perk their interest in these cases so that the next time they see something out of the ordinary, they will think about referring to a specialist. By communicating with the primary care physician or the referring neurologist we can alert them to other cases that may arise in the future."
Dr. Govindarajan disclosed relevant relationships with MT Pharma. Rodriguez and Dr. Friedenberg disclosed no relevant relationships with industry.
Link Up for Related Information:
Palese F, Sartori A, Logroscino G, Pisa FE. Predictors of diagnostic delay in amyotrophic lateral sclerosis: A cohort study based on administrative and electronic medical records data. Amyotroph Lateral Scler Frontotemporal Degener 2019;20(3–4):176–185.