Leprosy
mailing list – May 13th , 2005
Ccn: all.
Ref.: sensory testing.
From: R de Soldenhoff, Makassar,
South Sulawesi, Indonesia.
Re: ball
point pen method for sensory testing: a `low sensitivity` test
Dear Salvatore,
Dr. Narasimha Rao raised important points regarding examination for
sensory
loss (LML May 4th,
2005).
1.
I would first
like to refer readers to the two useful and recently available texts
which cover this. Both are freely available in book form, as well as
electronic form (if you have Adobe Reader). They are:
. WHO's Guide
to Eliminate Leprosy as a Public Health Problem (www.who.int/lep/ - click on Guide
to Eliminate Leprosy)
. ILEP's How
to Diagnose and Treat Leprosy (www.ilep.org.uk
- click on Technical Advice, then on Teaching Material, then on
language, then on LG1)
2.
There are two
issues here. The first is making a diagnosis of
leprosy in
a new patient. A cardinal sign is required and the most common, which
will establish the diagnosis, is “loss of sensation in a skin
patch”. As this examination is most often carried out in a simple
clinic setting by multipurpose health workers, the instructions need
to be clear and the tools need to be simple. The worker should be
looking for clear evidence; proof that there is some, definite, loss
of sensation in the skin patch. This may be slight, but needs to be
clearly demonstrable. A sensitive test is therefore necessary. In
India
, traditionally a feather has been used, as illustrated on page 17 of
the WHO booklet. Also in
India
, but more commonly elsewhere, a teased out piece of cotton wool is
normally used, as illustrated on page 6 of the ILEP booklet.
The statement
on page 16 of the WHO booklet, "Take a pointed object, such as a
pen" (even although it is qualified with "lightly touch . the . patch")
is clearly inappropriate in this circumstance. The ideal, universally
available instrument for this test is cotton wool.
3.
The second
issue is the assessment of nerve function loss: sensory, motor and
autonomic. This may be required to make the diagnosis as it is part of
the second cardinal sign: “an enlarged peripheral nerve with
evidence of nerve function loss”. It is needed to identify patients
at risk of developing further disability. It is also a necessary
examination to detect neuritis/reaction involving a peripheral nerve
and should be carried out and recorded at the time of diagnosis and
regularly thereafter (in most settings,
at the time of collection of the monthly dose of MDT and more
frequently when there is a reaction). Again, the worker is looking for
evidence. This time it is for damage to key nerves, such as the ulnar,
median and posterior tibial nerves. As this includes testing sensation
on the palms of the hands and soles of the feet of manual workers, a
feather or cotton wool is inadequate, and hence (since the 1970s) the
recommended instrument is a pencil or ball pen, to be used
"gently on the skin to make a small depression" (ILEP
booklet page 9 with illustrations). Graded
monofilaments are undoubtedly more sensitive, but are difficult to
introduce in most clinic settings. Therefore, the ideal instrument for
this test is a ball pen.
With kind regards,
Richard
Dr. Richard de Soldenhoff
NLR Medical Officer, Eastern Indonesia
Jalan Durian No. 5
Makassar,
South Sulawesi
Indonesia
Tel. and fax. 62.411.854352
Mobile.62.813.4241 4432
Email: rdesoldenhoff@hotmail.com.
