Calls to scrap diagnosis of 'Parkinson's disease', with one in four misdiagnosed

November 20, 2016   By medical reporter Sophie Scott

As many as 25 per cent of patients who are told they have Parkinson's disease actually have other degenerative brain illnesses, prompting Australian doctors to investigate more accurate ways to diagnose the illness.

Key points:

•   Many diagnosed with Parkinson's may have dementia with Lewy bodies

•   Expert says it is dangerous to confuse the conditions

•   Australian doctors taking part in a worldwide trial that could more accurately diagnose patients

The widow of the late actor Robin Williams revealed that her husband was actually suffering from a condition called dementia with Lewy bodies (DLB), a complex and often misunderstood brain illness.

Journalist Liz Jackson turns the camera on herself to reveal her diagnosis of Parkinson's.

And former award-winning ABC journalist Liz Jackson has also been diagnosed with Parkinson's disease and told there was evidence she also may have DLB.

In patients with either Parkinson's or DLB, abnormal clumps of the same protein is present in the brain, though often it is found in different parts of the brain.

Simon Lewis says,Mistreatment of dementia with levy bodies can be deadly

That has led some doctors to want to scrap the terms Parkinson's disease and dementia with Lewy bodies and call it all Lewy Body disease.

However, a move is not supported by Professor Simon Lewis, from the Brain and Mind Research Institute at the University of Sydney.

"In the absence of a cure, people want to know what their future holds and you can't tell the future when you don't have a diagnosis," Professor Lewis said.

"Calling it Lewy Body disease doesn't help to explain to patients and their families what might happen to them."

Professor Lewis studies and treats patients with both conditions and said they displayed quite different symptoms.

"In Parkinson's, you see primarily physical symptoms such as tremor, which can usually be controlled for years with medication," he said.

He said in DLB, patients have had significant memory problems and often progress to dementia within two years.

Knowing which illness patients have is crucial, as some medications commonly prescribed for Parkinson's disease can be fatal for DLB patients.

The mainstay treatment for Parkinson's called levodopa can often aggravate patients who have DLB.

"It can make them more confused and increase hallucinations," Professor Lewis said.

"If patients who are told they have Alzheimer's disease but actually have Lewy body dementia are given the older anti-psychotic drugs such as Risperidone, it can be fatal."

Trial to diagnose patients earlier

Australian doctors are taking part in a worldwide trial that could more accurately diagnose patients with Parkinson's disease.

More than 600 patients are being recruited at 10 centres around the world, including the Brain and Mind Centre.

It will test patients on their sense of smell, and investigate whether they have sleep disorders which can both be risk factors for Parkinson's disease.

"We are hoping to find out can we develop diagnostic tests to determine who has which illness," Professor Lewis said.

"Until then, educating patients and doctors about the differences in the illnesses is the key to getting the proper diagnosis."

The ultimate hope is to more accurately diagnose DLB to be able to identify biomarkers in the blood and develop PET scans which can pick up the protein found in the brains of patients.

http://www.abc.net.au/news/2016-11-21/calls-to-scrap-diagnosis-of-parkinson's-disease/8038220?