The patient is a 37-year-old right-handed Caucasian man who was in his usual state of health until December 2006 when he started to notice that his feet were cold, numb, and had a tingling sensation (described as pins and needles) from the ankles down. In a few weeks, the tingling sensation progressed up to the knees which remained stable for the next three months. In April 2007, he also noted the tingling sensation in the arms.
At time of his presentation to our pain clinic and neurology clinic in October 2007, he reported diffuse constant tingling sensation, mostly involving his arms, legs, and face, which was accompanied by sharp pains, mostly in the feet and distal legs. The pain was rated on average as an 8 on a numerical rating scale (NRS) (0 is no pain and 10 is most severe pain imaginable). He also reported episodic lower extremity allodynia to light touch and burning dysesthesia in his trunk and hands. These symptoms kept him up at night and disturbed his sleep. He began to experience symptoms of depression secondary to the relentless pain condition. He denies weakness. Physical examination at the time of presentation was significant for decreased light touch sensation and hyperalgesia to pinprick in a stocking-glove distribution. Motor strength, proprioception, and tendon reflexes were well preserved.
A nerve conduction study and electromyography was normal showing no evidence of a large fiber peripheral neuropathy or radiculopathy. We further conducted skin biopsies at the distal leg (DL), distal thigh (DT), and proximal thigh (PT) in the Cleveland Clinic Cutaneous Nerve Laboratory and carried out intraepidermal nerve fiber density (IENFD) analysis as previously described. Intraepidermal nerve fiber density was significantly reduced at the distal leg as compared to normal control (Figure 1), which indicates a distal small fiber sensory neuropathy. The neuropathy etiology evaluation was significant for diabetes mellitus as revealed by oral glucose tolerance test with a 2-hour glucose level being 220 mg/dL. ESR, ANA, ENA, rheumatoid factor, ACE level, ANCAs, TSH, free T4, serum and urine immunofixation, folic acid, vitamin B12, RPR, Lyme serology, and heavy metal screen were all unremarkable.
 He was diagnosed with painful diabetic small fiber sensory neuropathy and started on Glucophage. In terms of his neuropathic pain control, however, he had failed to respond to multiple pain medications, including Topiramate, Oxcarbazepine, Duloxetine, Amitriptyline, Darvocet, Tramadol, and Lidocaine transdermal patches. Gabapentin only offered minimal pain relief. Given the unsatisfactory outcomes of conservative treatment, we decided to try a lumbar sympathetic block for his pain and allodynia in the low extremities. We used the classic approach for bilateral lumbar sympathetic block at the level of L3 under fluoroscopic guidance and injected a mixture of 12 mL of 1% Lidocaine and 20 mg Triamcinolone on each side. The temperatures, monitored in the plantar surface of the big toes (LS 14000 Temperature Monitor and Skin Temperature Probe, NovaMed, NY, USA), increased significantly, and NRS pain scores decreased substantially after the procedure as shown in Table 1 (initial block) and Figure 2.
At his 2-month followup, the patient reported "excellent" relief of his foot pain bilaterally for over 6 weeks, but became more cognizant of his thoracic and hand pain. A decision was made to proceed with a repeat lumbar sympathetic block to further enhance the pain relief. Subsequent temperature and pain score changes were again noted as shown in Table 1 (2 months) and Figure 2. Management of his thoracic pain was further considered at the following office visit. At a follow-up visit 4 weeks later, the patient again reported "significant, sustained" relief of his bilateral foot pain. He felt "dramatic" improvement of the "coldness and tingling pain" with the first injection with sustained relief that was further enhanced with the second procedure.
At this point, his chief complaint became the "hypersensitive, pins and needles, burning" thoracic and abdominal pain that was described as occupying a discrete antero-/posteroarea of his thorax, roughly covering the T6 to the L1 dermatomes. Physical examination, as previously described, was significant only for bilateral lower extremity stocking-distribution decrease in sensation to light touch and pinprick. He returned 2 weeks later for a T8 bilateral paravertebral sympathetic nerve block, which was performed in the classic fashion, under fluoroscopic guidance. A solution of 1% Lidocaine 10 mL and 20 mg Triamcinolone was injected on each side. The patient was maintained on the same doses of Gabapentin and Tramadol. Upon his return to the clinic 4 weeks later, he reported "70%" relief of his thoracic pain following his T8 paravertebral block. By this point, his bilateral foot pain was 5 on the NRS three months following his second lumbar sympathetic block; therefore, a third bilateral lumbar sympathetic block was performed (Table 1, 4 months). Pain medications remained the same, and the patient was followed up in three months.
Over the next two years, the patient continued to have lower extremity neuropathic pain as described above with good, sustained pain relief after each of subsequent lumbar sympathetic blocks. The intervals of each block are shown in Table 1 (Figure 2) with the corresponding temperature changes and the NRS pre- and postblock pain scores. He additionally underwent two thoracic paravertebral blocks at the T6 level in April and May of 2010 with good relief following each procedure. The remainder of his clinical course was uneventful.