pain management,,,,,

1. Diabetic Neuropathy

2. Definition
‘‘The presence of symptoms and /
or signs of peripheral nerve
dysfunction in people with diabetes
after the exclusion of other causes.’’

3.  Diabetic peripheral neuropathy (DPN) is the
most common form of peripheral neuropathy
and one of the most common diseases
affecting the nervous system.
 DPN affects greater than half of diabetic
patients with a history of more than 25 years
of diabetes.
 DPN can lead to limb loss and death
 Up to 50% of DPN patients can be
asymptomatic

4. Pathophysiology
 Direct toxic effects of the glucose on nerve cells.
Accumulation of sorbitol, formation of advanced
glycosylation end products, free radical-mediated
oxidative stress, abnormalities in essential fatty acids,
and deprivation of nerve-growth factors
 Microvascular dysfunction- damage to vasa
nervosum due to thickening of the capillary basement
membrane.

5. Role of sympathetic nervous
system
 Elevated levels of norepinephrine in
symptomatic DPN.
 Relatively higher number of functioning
sympathetic fibers contributing to the pain.
 Impaired sympathetically mediated
vasoconstriction contributing to the
inappropriate local blood flow.

6. Types of DPN
a. Distal and symmetric peripheral
neuropathy ( most common) 80%-
1. Small and unmyelinated (C fibers)
2. Thicker fibers that are more or less
myelinated (Ad, Ab)
b.Motor fibre neuropathy- alpha fibres, motor
weakness
c. Autonomic neuropathy
d. Inflammatory neuropathy

8. Clinical presentation
 Most common is distal and symmetrical type
also called length dependant diabetic
neuropathy.
 Symptoms initially begin in the feet and then
gradually progress upwards.
 This is because the longest nerve fibers are
affected first. That’s why the name length
dependant polyneuropathy. Sensory defects can
usually be observed in the hands when the
sensation around the knee is affected.

9.  Although there is an interval of a few years
between the appearance of DM and the
manifestation of LDDP, these symptoms
can be the first symptoms of type 2 DM.
 diminished sensation; burning feet, which
may occur particularly during the night and
worsen when touched; and the sensation
of tingling in the feet.
 Attacks of shooting pain also occur.

10. Autonomic neuropathy
 The autonomic manifestations in DM may
include orthostasis, rhythm disorders,
gastroparesis, gastric function disorders,
renal function disorders, and pupillary
defects

11. Examination
 General inspection of feet-
skin,thickening,cracking,ulceration
 Musculoskeletal assesment-charcot
arthropathy
 Neurological assessment
 Assesment of H.R & B.p.(lying/sitting)

12. Examination
 The neurological examination should include at least the
following:
(1) examination of all qualities of somatosensory function
(2) reflexes
(3) muscle strength.
One of the signs is diminished sensitivity to a pinprick
along with reduced temperature sensitivity (ie, sensory
examination of the spinothalamic tract). A decrease in
proprioception may be manifested as, for example,
abnormal sensation of position of the joints (toes,
increased risk of falling), reduced pressure sensation,
blunted two-point discrimination, or a reduced sense of
vibration. Allodynia and hyperpathia can also occur.

14. Investigations
 Nerve conduction studies- delay in the
conduction velocity.
 But can be normal if there is only small
fiber involvement.
 Motor: early – preserved
advanced – decreased

15. Diabetic neuropathy symptom
score (DNS)
 Items Rate
Unsteadiness in walking 0=absent,1=present
Numbness 0=absent,1=present
Burning ,aching pain or 0=absent,1=present
Tenderness in leg/feet
Pricking sensation 0=absent,1=present
Maxm- 4 points
1 or more points- neurological abnormalities

16. Treatment
 Improving the glycemic control.
 Neuropathic pain medications
 TCAs
 SNRI
 Anti-convulvasants
 Opioids

17. Antidepressants
1. Tricyclic antidepressants (TCAs)- studies
show that they are the most effective
drugs. Limited by side effects.
2. SNRI- duloxetine at the dose of 60-120
mg gave >50% pain relief compared to
placebo in >505 pts.

18. Anticonvulsants
1. Gabapentin- efficacy similar to
amitryptiline.
2. Pregabalin- Data from six larger studies
with pregabalin showed a pain reduction
of more than 50% in 39% and 46% of the
patients, with 300 mg and 600 mg per
day, respectively.
3. Carbamazepine- less effective than
preabalin.

19. Lignocaine
 5% lignocaine medicated plasters- it was
compared with pregabalin for DPN in an
RCT where both were effective but
lignocaine treated patients had less
adverse effects.
 IV lignocaine- a small double blind study
showed that the 5-7.5 mg/kg of lignocaine
given as infusion over 4 hrs at 4 weekly
interval reduced pain for next 15-28 days.

20. Opioids
 Studies have shown that opioids are
effective in DPN.
 Morphine, tramadol, oxycodon.
 Combination of tramadol and paracetamol
is as effective as gabapentin.

21. Other treatment options
 Capsaicin cream 0.075% for local
application.
 Antioxidants- alpha lipoic acid- 600mg iv
for 4-5 wks.

23. Interventional management
 Sympathetic block may be effective
 Spinal cord stimulation