What is CIDP
I found a video specifically about CIDP, from an expert in this field, talking to other neuro-consultants about what CIDP is and is not:
Richard J. Barohn, M.D. - Chair, Dept. of Neurology, University of Kansas Medical Centre
Below is a synopsis of the hour long video, presented in November 2012, to an audience of medical experts. It has taken me around 10 hours to de-crypt some of the terms and slides used. Apologies if I have made this too technical, but I have tried my best to make it understandable.
If you want to watch the full version it is available @ http://www.gbs-cidp.org
What is CIDP
Q: What pattern of Neuropathy specifically defines a sufferer from CIDP?
A: Symmetric proximal and distal weakness with sensory loss
Explanation: Muscle weakness away from the core of the body (i.e. in the arms &/or legs) with loss of feeling within those same limbs. The weakness & loss of feeling being the same down both sides of the body (left and right)
If you just have loss of feeling - this can be caused by other issues (e.g. Diabetes)
If it is not the same on both sides, these are other conditions linked to CIDP/GBS.
How to prove it is CIDP
Q: What is the best test for CIDP?
A: Nerve conduction studies (NCS)
Explanation: There are two types of nerves Motor (control movement) and sensory (control feeling). Both can be tested to see how fast they react to an electrical stimulation. This measures the speed it takes for the signals to get from the one place to another (latency measured in milliseconds) and is performed in a hospital or clinic.
Though a Lumbar Puncture can also be used (CerebroSpinal Fluid - CSF, or Spinal Tap), this measures the levels of proteins found in the spine and is another good indicator of CIDP if they are high, the presentation states that this backs up the NCS findings
What NCS Values point to CIDP? Below is a table taken from one of the slides which just proves how complex and difficult medical people seem to want to make it for the ordinary person in the world to understand what they are saying!
Richard J. Barohn, M.D. - Chair, Dept. of Neurology, University of Kansas Medical Centre
Below is a synopsis of the hour long video, presented in November 2012, to an audience of medical experts. It has taken me around 10 hours to de-crypt some of the terms and slides used. Apologies if I have made this too technical, but I have tried my best to make it understandable.
If you want to watch the full version it is available @ http://www.gbs-cidp.org
What is CIDP
Q: What pattern of Neuropathy specifically defines a sufferer from CIDP?
A: Symmetric proximal and distal weakness with sensory loss
Explanation: Muscle weakness away from the core of the body (i.e. in the arms &/or legs) with loss of feeling within those same limbs. The weakness & loss of feeling being the same down both sides of the body (left and right)
If you just have loss of feeling - this can be caused by other issues (e.g. Diabetes)
If it is not the same on both sides, these are other conditions linked to CIDP/GBS.
How to prove it is CIDP
Q: What is the best test for CIDP?
A: Nerve conduction studies (NCS)
Explanation: There are two types of nerves Motor (control movement) and sensory (control feeling). Both can be tested to see how fast they react to an electrical stimulation. This measures the speed it takes for the signals to get from the one place to another (latency measured in milliseconds) and is performed in a hospital or clinic.
Though a Lumbar Puncture can also be used (CerebroSpinal Fluid - CSF, or Spinal Tap), this measures the levels of proteins found in the spine and is another good indicator of CIDP if they are high, the presentation states that this backs up the NCS findings
What NCS Values point to CIDP? Below is a table taken from one of the slides which just proves how complex and difficult medical people seem to want to make it for the ordinary person in the world to understand what they are saying!
Explanation (I hope!):
NCV - Nerve Conduction Value (metres per second)
DL - Distal Latency (signal travel time between 2 points)
F Waves - time for signal to travel back to central nervous system
LLN - Lower Limit of Normal (you've got to love them!)
ULN - Upper Limit of Normal
Location of Nerves (leg below, arm at top of page):
NCV - Nerve Conduction Value (metres per second)
DL - Distal Latency (signal travel time between 2 points)
F Waves - time for signal to travel back to central nervous system
LLN - Lower Limit of Normal (you've got to love them!)
ULN - Upper Limit of Normal
Location of Nerves (leg below, arm at top of page):
So for each of the different nerves in the arm, the NCV needs to be less that 33.6 metres/second (<70%) for them to be fairly certain it is CIDP, with the norm being 48. In the legs this is 29.4 against 42.
For the Median nerve in the arm the time needs to be over 6.7 milliseconds (>150%) against the norm of 4.5 and the Ulnar is 5.4 to 3.6 (why these are different I don't know - I presume they have to be different lengths). In the legs they are the same at 9.9 against 6.6 milliseconds. The Time for the signal to travel back to the central nervous system is different for all @ Median: 46.5 to 31, Ulnar: 48 to 32, Peroneal: 84 to 56 and Tibial 87 to 58. |
Useful Tests or Not?
Nerve biopsies are not useful for detecting CIDP - a lot of places can't process them properly (in the US? - bar Huston and a couple of others) and the information can be conflicting as there is no definite outcome. Also the I stands for inflammation and there is not always inflammation shown in the nerve biopsy (maybe the disease needs renaming?)
CSF examinations (lumbar punctures) show high levels of proteins in 80-90% of cases, however if the other symptoms were there then even with levels at 40 - 50 this would still be CIDP.
Diabetics having CIDP appears more common and the reasons are that Diabetes is a Neuropathy (but without the weakness) and it is possible for the nerve conduction values to creep into the range for CIDP.
The doctor states that: "In his opinion a reasonable number of diabetics get incorrectly diagnosed with CIDP!"
As the weakness can be there for any other reason and the first 2 or 3 seconds of the tests prove how much weakness they have, so after the first couple of seconds if it becomes easier to push against their movement this doesn't count.
Diabetic patients are the toughest cases to sort out - there must be definite symptoms in all other areas. As they will usually have numbness in their feet. The doctor said he would expect significant weakness in the arms as one of the key differentiators.
One of the doctors attending stated he uses 5 points and if the patient has 3 out of 5 then it is CIDP:
With diabetics this must be much higher (in fact you need all 5)! As they can have a number of the above.
Below is the chart shown in diagnosing CIDP:
Nerve biopsies are not useful for detecting CIDP - a lot of places can't process them properly (in the US? - bar Huston and a couple of others) and the information can be conflicting as there is no definite outcome. Also the I stands for inflammation and there is not always inflammation shown in the nerve biopsy (maybe the disease needs renaming?)
CSF examinations (lumbar punctures) show high levels of proteins in 80-90% of cases, however if the other symptoms were there then even with levels at 40 - 50 this would still be CIDP.
Diabetics having CIDP appears more common and the reasons are that Diabetes is a Neuropathy (but without the weakness) and it is possible for the nerve conduction values to creep into the range for CIDP.
The doctor states that: "In his opinion a reasonable number of diabetics get incorrectly diagnosed with CIDP!"
As the weakness can be there for any other reason and the first 2 or 3 seconds of the tests prove how much weakness they have, so after the first couple of seconds if it becomes easier to push against their movement this doesn't count.
Diabetic patients are the toughest cases to sort out - there must be definite symptoms in all other areas. As they will usually have numbness in their feet. The doctor said he would expect significant weakness in the arms as one of the key differentiators.
One of the doctors attending stated he uses 5 points and if the patient has 3 out of 5 then it is CIDP:
- Progressive course - it is getting worse slowly
- Symmetrical proximal weakness
- Loss of reflex - also EMG's
- High CSF Proteins
- Demylinating Features
With diabetics this must be much higher (in fact you need all 5)! As they can have a number of the above.
Below is the chart shown in diagnosing CIDP:
And this is my translation:
The actual terminology used is terrible for the normal person, so I apologise for this. However the doctor did state that getting hung up specifically on these criteria is not helpful to the potential patient.
I do have diabetes. So by this scale I don't have CIDP? As there was no issues with my arms ever - they were and are 100% OK! However I did tick all the other boxes. Unfortunately for me, I did and do have CIDP, so the CSF, EMG and complete lack of reflexes in my legs proved this.
I do have diabetes. So by this scale I don't have CIDP? As there was no issues with my arms ever - they were and are 100% OK! However I did tick all the other boxes. Unfortunately for me, I did and do have CIDP, so the CSF, EMG and complete lack of reflexes in my legs proved this.
So the Qualifying Criteria Are.....?In 2009 a supposedly definitive list for qualifying for CIDP was produced (by statisticians and leading Neurologists in the US). The simplified version is:
Patients with symptoms for over 8 weeks would be classed as CIDP if:
AND EITHER
OR
However these are not seen as relevant by the majority of NEUROLOGISTS!
Treatments
The only treatments that are proven (clinically in a randomised control trial - RCT) to work on CIDP are:
Dr Barohn states his recommended 1st line treatments are Prednisone or IVIG and if they do not respond then switch to the other (say after a couple of months). Roughly 50% respond to the first and 50% respond to the second, so 75% overall. If they are already in the hospital then Plasma is a much easier option as this makes it much easier to administer.
Other potential treatments mentioned (copyright names in brackets):
SubCutaneous IVIG (SCIG) - new development of IVIG trials being run now.
Improvements are seen first in the muscles nearer to the core (hips, shoulders) before the ones further away (feet, fingers).
CIDP Prognosis
In 1975 (P J Dyck) created a set of stats and this was reviewed in 2007:
1975 2007
Mortality: 11% 3.1%
Working with Disability: 60% 63%
Not Working: 8%
Wheelchair bound: 28% 7%
Recovered: 4% 31.1% (however with treatment)
Aids to Walk: 28%
CIDP Caveats
The likelyhood of patients ever fully recovering is very low, less than 10%. Most people will never recover fully and to tell them so is completely misleading. Strength will be much better - hopefully, but there will be weakness remaining. With CIDP there is a significant chance of relapse, but no one knows how or why and if you survive 5 years this chance gets significantly less.
Patients with symptoms for over 8 weeks would be classed as CIDP if:
- No genetic abnormality
- No other substances introduced for other issues
AND EITHER
- 75% of nerve tests had a response with over 50% of these showing an issue
OR
- Symmetric weakness in all four limbs and weakness in at least one of the hips and shoulders
However these are not seen as relevant by the majority of NEUROLOGISTS!
Treatments
The only treatments that are proven (clinically in a randomised control trial - RCT) to work on CIDP are:
- Prednisone (Steroids) - 40 to 95% of patients respond positively, after 2 months of usage is the peak benefit. There is a 30% chance of remission - My observations are this is 30 to 50% respond and usage tends to be much longer with nasty side effects.
- Plasma Exchange - similar responses to Steroids - the main issue is access as it has to be administered in hospital and is time consuming and very expensive (thus not the first line therapy) - again my conclusions are the treatment is much less positive than Dr Burt states and less than steroids.
- IVIG - much later process, though the initial trials were much shorter - 6 weeks. Around 40-50% respond. Later trials showed similar numbers made an improvement (on arms and legs) at 47.5%, though in the same trials 22.5% who had placebo improved which means you get better anyway. But they still don't know how it works! This seems the latest method, though it depends on where you are in the world which actually is preferred. Still requires visits to hospital and is very expensive.
Dr Barohn states his recommended 1st line treatments are Prednisone or IVIG and if they do not respond then switch to the other (say after a couple of months). Roughly 50% respond to the first and 50% respond to the second, so 75% overall. If they are already in the hospital then Plasma is a much easier option as this makes it much easier to administer.
Other potential treatments mentioned (copyright names in brackets):
- Mycophenolate (Cellcept) - Not proven
- Interferon (Avonex) - trials negative
- Etanercept (Enbrel) - not proven
- Rituximab (Rituxan) - not impressed in neuropahy, not seen much response
- Alemtuzumab (Campath) - too toxic!
SubCutaneous IVIG (SCIG) - new development of IVIG trials being run now.
Improvements are seen first in the muscles nearer to the core (hips, shoulders) before the ones further away (feet, fingers).
CIDP Prognosis
In 1975 (P J Dyck) created a set of stats and this was reviewed in 2007:
1975 2007
Mortality: 11% 3.1%
Working with Disability: 60% 63%
Not Working: 8%
Wheelchair bound: 28% 7%
Recovered: 4% 31.1% (however with treatment)
Aids to Walk: 28%
CIDP Caveats
- Don't undertreat (IVIG especially - min 2 to 3 months)
- Don't overtreat (Steroids really nasty side effects)
- Don't expect too much from the treatments
- Change treatments if it doesn't work
The likelyhood of patients ever fully recovering is very low, less than 10%. Most people will never recover fully and to tell them so is completely misleading. Strength will be much better - hopefully, but there will be weakness remaining. With CIDP there is a significant chance of relapse, but no one knows how or why and if you survive 5 years this chance gets significantly less.