Nerve thickening standards

Leprosy Mailing List - September 21st, 2008

Note: The tables in this post are not easy to understand on this blog. You can also look at this post on the LML archives for easier understanding.

Ref.: Nerve thickening standards
From: Srinivasan H., Chennai, India

Dear Dr Noto,

This is with reference to the query raised by Dr KV Krishnamurthy about standards and gradation of nerve thickening in leprosy (July 31, 2008). My views on this are as follows.Involvement of peripheral nerves is such an essential feature of leprosy that one will not diagnose leprosy without any evidence for the same. Typical impairments (deformities and disabilities) due to damage to peripheral nerves is are complications of leprosy dreaded by affected persons. We therefore look, during clinical examination, for nerve involvement for two totally different reasons: (a) for help in diagnosing the disease and (b) also for help in assessing the risk of impairments resulting from damage to peripheral nerves.

Peripheral nerve involvement manifests clinically as:
(a) thickening elicited by palpation of the affected nerves;
(b) tenderness (pain elicited by normal palpation);
(c) spontaneous pain in the affected nerves (nerve pain); and
(d) nerve function deficit (NFD – sensori-motor-autonomic deficit).

It will be noticed that we do not have objective measurements for assessing the first three parameters (thickening, tenderness, pain) and that we depend on the subjective judgements, of ourselves or of the affected person. Certain amount of experience in clinical examination is necessary for making these judgements. The fact that these parameters are based on subjective appraisal does not mean that we cannot come to reasonably accurate conclusions like those based on objective measurements. I have used the following scales and found them useful and fairly accurately repeatable.
(a) Nerve thickening: a four-grade scale (0 to 3) is used.
Grade
Degree
Description
0.
No thickening
Nerve undoubtedly feels normal
1
Mild thickening
Probably thickened or doubtful thickening
2
Moderate
Nerve undoubtedly feels thickened
3
Severe
Nerve is grossly thickened
Greater accuracy than what is obtained with this grading does not appear necessary or useful.
(b) Nerve tenderness: a four-grade scale (0 to 3) is used.
You palpate the nerve and watch the subject’s behaviour. If the subject does not indicate that palpation was painful, ask whether feeling the nerve was painful.
Grade
Degree
Description
0
None
Says palpation is not painful even when asked about it.
1
Mild
Says palpation is painful only when asked about it
2
Moderate
Indicates palpation is painful even without asking about it
3
Severe
Is scared of palpation. Jumps, or, tries to withdraw the part. Tries to avoid palpation
I have found the above described four grade system quite adequate for our purposes. It has also been found it repeatable with fairly low inter observer variation.
(c) Nerve pain: A four-degree scale (0 to 3) is used.
Grade
Degree
Description
0
None
Does not complain of nerve pain; says ‘no nerve pain’ even when asked about it
1
Mild
Complains of nerve pain even when not asked about it. But, says ‘it is not severe ‘ when asked about it.
2
Moderate
Says ‘it is severe’ when asked about it. But says it does not interfere with sleep and demonstrates that the movement of the adjoining joint is not restricted by pain.
3
Severe
Says ‘pain is severe, and/or that it interferes with sleep; and/or movement of the adjacent joint is restricted because of pain.

Other recognized methods of grading pain are to ask the subject (a) to locate the level of his/her pain on a pain line (like a number line marked zero at one end and 10 at the other end), or, (b) describe the severity of the pain in terms of monetary units, with one rupee or one dollar as the most severe or intolerable pain.

Though the above are qualitative scales, they are reasonably reliable and accurate and can be used like quantitative scales, provided we do not give the numerical values more than their due (e.g., Gr. 2 is not twice as much as Gr. 4).

Thank you.

H. Srinivasan

Note: The tables in this post are not easy to understand on this blog. You can also look at this post on the LML archives for easier understanding.