It is an irrefutable fact that diagnosis is vital to medical care. It creates pathways for creation and implementation of treatment plans. Conversely, we have all heard stories of people suffering due to misdiagnosis of their condition. Being not prescribed a treatment to being given wrong treatment to being confused and even worsening of their condition are all too common in all medical setups, small and big - could all stem from being misdiagnosed.
This has been observed many times with patients having PD. In a survey of 2000 people in UK, with PD, it was found that more than quarter (26%) reported they were misdiagnosed with a different condition before receiving the correct PD diagnosis.
There can be either of the below types of misdiagnosis of PD:
Initially a PD diagnosis is given, but later it turns out that it was not PD but some other condition.
Person is diagnosed with another condition, but later found that it was actually a case of PD.
There are few reasons sighted for the misdiagnosis of PD:
PD is a complex condition, with more than 40 known symptoms. Everyone’s symptoms are different, the order in which they appear and the way and pace at which these symptoms progress would also be different.
2. As it stands today, there is no definite test for PD. In the sense that no lab test or imaging can definitely diagnose PD. Diagnosis is done primarily based on symptoms and its history and that is a clinical diagnosis. Sometimes, brain scans like Trodat and F-DOPA are prescribed, but they are also not perfect. Though, if these scans are normal - one can safely say that PD is not present, but these are abnormal - one cannot safely say it is PD, and a PD mimic.
3. There are other conditions that mimic PD. We shall describe those in more detail below.
Conditions that have symptoms similar to PD and can contribute to misdiagnosis, are collectively called ‘Parkinson’s mimics’.
These can be classified into:
Drug induced Parkinsonism - Some psychiatric, anti-vertigo or blood pressure medication can give symptoms like that of PD
PD Plus syndromes - where the condition has more symptoms than just PD-like which could be a tell-tale sign to make the correct diagnosis
Mimics caused by brain destruction - Excessive copper, iron or calcium in the brain, brain damage due to cardiac arrest, infections like HIV
Completely unrelated mimics
Below are certain named conditions that are mistook as PD:
Essential Tremor - This is usually tremor in hands or arms and on both sides, while the limbs are active. This is similar to PD but different too as PD tremor usually starts on one side and is present when the limb is rest, not active.
NPH - In this condition, the cerebral spinal fluid does not drain properly. This can result in symptoms similar to PD like slow movements, impaired thinking etc.
Dementia with Lewy bodies - This is a type of dementia where memory and thinking issues come up first, due to buid-up of certain protein in the brain. This happens to some PD patients too, but in later stages.
Multiple system atrophy - Here symptoms resemble PD, but can have more signs like urinary symptoms, decrease in sweating etc.
PSP - Here too, there can be more symptoms like falls in early stage, difficulty with speech, limited eye movements etc.
Picture credit : https://parkinsonsdisease.net/living/common-misdiagnoses