Primary Cutaneous Nocardiosis in a Heart Transplant Patient: A Case Report

Abstract

A 38-year-old female with history of longstanding non-ischemic cardiomyopathy underwent orthotopic heart transplantation (OHT). Her past medical history was significant for factor V leiden and methylenetetrahydrofolate reductase (MTHFR) heterozygous deficiencies with chronic pulmonary embolism, sickle cell trait, atrial flutter, type 2 diabetes mellitus, and hypertension. The patient had a long and complicated course post-transplantation. Immediately after OHT, she was noted to have donor-specific human leukocyte antigen (HLA) antibodies treated with 5 cycles of plasmapheresis. On further biopsies it was noted that she had acute cellular rejection requiring pulse-dose parenteral steroids on multiple occasions. Her immunosuppression therapy consisted of tacrolimus, mycophenolate and prednisone. Six months post-transplant she was noted to have a spontaneous 4cm right calf muscle hematoma based on lower extremity ultrasound that was felt to be due to her underlying hematologic disease. At 7 months post-transplant the patient was hospitalized twice. The first admission was for multifocal necrotizing pneumonia. Although sputum cultures were non-diagnostic, the patient improved with 2 weeks of antibiotic treatment. The second admission occurred after a routine right heart catheterization that showed hemodynamic parameters concerning for rejection. At that time, the patient received empiric parenteral pulse steroids while waiting for final pathology results; these were negative for rejection and the patient's immunosupressants were continued at previous doses.The newest hospitalization was 8 months post-transplant, when she was admitted with a chief complaint of worsened right-sided calf pain for a month. On physical exam the patient was noticed to have an area of warmth, induration and palpable tenderness. Patient denied any other symptoms, and specifically denied fevers, chills, respiratory symptoms or trauma. Imaging studies on admission included a lower extremity ultrasound that showed the hematoma had increased in size to 9 cm from previous study 2 months prior. Lab studies to assess any acute hematologic cause of recurrent spontaneous hematoma were negative. The differential diagnosis on admission included a leg abscess; however the absence of fever, leukocytosis and loculations made it seem unlikely. A calf MRI performed 4 days later showed the collection had increased to 13 cm. It was complex but still compatible with hematoma, although superimposed infection could not be ruled out. At this point it was decided for the patient to undergo an ultrasound guided fluid aspiration for diagnostic and therapeutic purpose, given the patient's continuing pain and rate of growth. Fluid aspiration yielded 50 cc of pus. Broad spectrum antibiotics were started, and that evening the patient went to the operating room for an incision and drainage. The following day the wound culture grew a modified acid fast gram positive bacilli (by modified Kinyoun method) that immediately raised the concern for infection with nocardia speci...