Complex regional pain syndrome presenting as a lump in the abdomen following post-pneumonectomy: An unusual case presentation

Dear Editor, The inherent challenges of thoracotomy include neuropathic pain due to the cutting of T3-T10 intercostal nerves, visceral pain of lung parenchymal, somatic pain, and persistent postsurgical pain syndromes (PSPSs).[1] We present a case of a 45-year-old male presented with left-sided upper back pain following left lung pneumonectomy. The perioperative course of the surgery was uneventful. After 1 ½ months of surgery, the patient reported dullness, continuous to intermittently sharp pain, a visual analogue scale (VAS) score of 9–10/10, and pain on wearing clothes, touch, and pressure. The skin on the left upper back was reddish and had local swelling, hyperalgesia, and allodynia to touch, pinprick and on application of brush and pressure [Figure 1a and b]. The left shoulder had limitations in abduction, adduction, and extension. The discomfort in the epigastrium and the left hypogastrium occurred with the intermittent appearance of a lump while eating food and drinking water. The epigastric pain was continuous, with intermittent episodes of vomiting and constipation, and the patient complained of pain while lying down straight. The laboratory parameters and imaging study revealed no active infection. The patient received oral gabapentin/nortriptyline 100/10 mg twice daily, and later, the night dose was gradually increased to 300/10 mg. In addition, oral aceclofenac-paracetamol 100/325 mg twice daily, oral baclofen of 10 mg once daily, and laxatives were prescribed. After one week, the patient reported reduced pain, spasms, discolouration of the affected area, and improvement in shoulder movements [Figure 1c and d]. However, the patient had trouble tolerating sedation and dizziness. At three months of follow-up, the patient received T2-3 sympathetic block under fluoroscopic guidance with 5 ml of ropivacaine 0.2% and dexamethasone 4 mg. The VAS was reduced to 2–3/10. After one month, VAS was 4/10, and a T2-3 sympathetic block was performed with 5 ml solution of 1% lignocaine and dexamethasone 4 mg. During follow-up, the patient is on oral gabapentin/nortriptyline 100/10 mg once daily with a reported VAS of 1–3/10 at one year and has resumed his work with a good quality of life.Figure 1: (a) Complex Regional Pain Syndrome (CRPS) II changes on the upper back in the post-pneumonectomy patient. (b) Swelling/lump formation in the epigastrium (c) Resolution of symptoms of skin colour changes and other features of CRPS II (d) Resolution of swelling/lump formation in the epigastriumIn the present case, the history of surgery and diagnostic features of the International Association for the Study of Pain (IASP) for Complex Regional Pain Syndrome (CRPS) indicated the diagnosis of CRPS II.[2] The first criterion was continuing pain, which was disproportionate to any inciting event. The second criterion was the presence of at least one symptom in three or more symptoms out of sensory, vasomotor, sudomotor (oedema), and motor (trophic) categories as per IASP criteria for CRPS. The third criterion was at least one sign in two or more sensory, vasomotor, sudomotor (oedema), and motor (trophic) categories as per IASP criteria for CRPS. The fourth criterion was that no other diagnosis could explain the signs and symptoms better.[2] The probability for persistent post-surgical pain or myofascial pain was ruled out in view of associated skin changes, oedema, and reduced range of shoulder movement, and CRPS II was the most appropriate diagnosis. The patient had allodynia to touch, temperature change (sub-acute CRPS), pain to deep pressure, limitation of shoulder joint movement, and hyperalgesia to pinprick, and all these resolved after treatment. The visceral changes reported in the upper abdomen can be argued with spasms in myofascial pain and post-surgical persistent pain in isolated symptoms. Still, the IASP criteria of CRPS aptly satisfy the diagnosis in the present case. Moreover, the effect of sympathetic block in the patient confirmed the diagnosis of CRPS.[2,3] The features that make this case unique were the presence of contraction of thoracic inter-costal, anterior abdominal wall muscles, oesophagal smooth muscles, and stomach muscles leading to the abdominal wall muscle spasm, intermittent lump formation, and constipation. T2-T3 sympathetic block may improve visceral muscle pain, but pain relief effects beyond the duration of local anaesthetics are only possible in sympathetic-mediated pain like CRPS and not otherwise.[4] Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient consented to the images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.