Page 95 - The lraternational Journal of the Royal Society of Thailand.indd

The International Journal of the Royal Society of Thailand
Volume XV-2023

have symptoms of DSPN should also be considered because up to 50% of DSPN cases
may be asymptomatic. The screening protocol includes testing of large nerve fiber
function using 128 Hz tuning fork or 10 g-monofilament, tendon reflexes and testing
of small nerve fiber function using pin prick sensation or temperature perception. All
DM patients should have annual 10 g monofilament to identify feet at risk for ulceration
and amputation. Foot inspection and peripheral arterial disease assessment can also

be performed during the same time (ElSayed et al, 2023; Nkonge et al, 2023).

Painful diabetic neuropathy (PDN)

Around one fourth of patients have pain associated with neuropathy, so called
: painful diabetic neuropathy (PDN). This pain is quite debilitating and associated with
impaired quality of life and long-term disability. The study from a tertiary care center

in Thailand showed lower quality of life, especially in physical domains when
compared to healthy Thai population. Moreover, the degree of severity is similar to
diabetic foot ulcer and other neurological illnesses (Kulkantrakorn & Lorsuwansiri,
2013).

The pain in PDN is quite interesting. Positive symptoms (such as spontaneous
pain, allodynia, hyperalgesia, paresthesia) and negative sensory symptoms (such
as anesthesia, hypoalgesia) may paradoxically coexist. The intensity of pain is in

moderate range in visual analog scale. Regarding pain characteristics, sharp pain,
surface pain, burning pain are more severe than other types of pain. This pain pattern
profile is different among each patient and it may aid in medication selection and
monitoring (Ziegler et al, 2021). Regarding the diagnosis of neuropathic pain, Thai
neuropathic pain guideline recommended Thai DN4 questionnaire (Thai version of
Neuropathique 4 Questionnaire ) for screening and diagnosis of neuropathic pain.

Pathogenesis

Multifactorial factors were proposed in the pathogenesis. The well-known ones
are hyperglycemia and microvascular etiologies. Chronic hyperglycemia leads to

increased reactive oxygen species which leads to oxidative stress, mitochondrial
dysfunction. Activation of protein kinase C, polyol pathway, protein kinase C and
advanced glycation end-products pathways, along with hyperinsulinemia will further
worsen inflammatory process manifesting as cytokines/chemokines production from
inflammation and final apoptosis. Regarding microvascular hypothesis, dyslipidemia
and inflammatory cascade cause the impairment of microvascular circulation in

nearby nerve environment. It will cause nerve ischemia or infarction and further
enhance genetic abnormalities and inflammatory vicious cycle (Feldman et al, 2019;
Ziegler et al, 2022; Ziegler et al, 2021).

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