Sickle Cell Ulcer in Hand Attributable to Arterio‐Venous Fistula
Bibliographic record
Abstract
Introduction: Sickle cell ulcers are a frequent dermatologic manifestation of sickle cell disease. They are almost exclusively described in the legs near the malleoli and are often bilateral. Such ulcers in the upper extremities are not described. We report a case of sickle cell ulcer in hand presumably related to arterio‐venous fistula in the forearm placed for hemodialysis in a patient with chronic kidney disease. Case: A 45‐year‐old African‐American man with a history of sickle cell disease, hypertension, and kidney failure treated with hemodialysis presented with a painful wound in his left hand near the base of his thumb, which had been present for 6 weeks prior to presentation. There was no history of trauma. 6 months prior to the development of the ulcer, the patient had an arterio‐venous fistula placed in the affected hand. The ulcer did not improve with use of antibiotics. Venous ultrasound of the left upper extremity showed occlusion of the cephalic vein and enlargement of the basilic vein. Subsequently, biopsy of the ulcer showed vascular proliferation with thickening of the vessel and obliteration of the vascular lumen. The blood vessels were plugged with sickled red blood cells, characteristic of sickle cell disease. Histological features of the lesion were indicative of vaso‐occlusive disease, suggesting sickle cell ulcer. Patient was treated with surgical débridement and skin grafting after hyperbaric oxygen therapy that only resulted in partial recovery of the lesion. Discussion: The pathogenesis of sickle cell ulcer is presumed to be related to a vaso‐occlusive process, leading to tissue necrosis resulting in skin ulcers. Ulcers can occur spontaneously or with local trauma. Low oxygen‐carrying capacity of the blood, impaired venous hemodynamics, and low hemoglobin are recognized contributing factors. The arterio‐venous fistula causing diversion of arterial blood probably contributed to the development of sickle cell ulcer. Conclusion: Sickle cell ulcers in the hand, although extremely rare, can occur in sickle cell patients with chronic kidney disease on hemodialysis with arterio‐venous fistula. This results from the altered local vascular hemodynamics that predispose to vaso‐occlusive conditions, eventually leading to ulceration.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".