An atypical presentation of necrotising fasciitis

Abstract

Necrotising fasciitis is a rare infection with a high mortality rate. Clinical manifestation may be influenced by an underlying disease state. We report a case of a 70-year-old man with an anaplastic large-cell lymphoma who presented with inconclusive signs of necrotising fasciitis following a neutropenic phase after chemotherapy. Surgical exploration did not reveal the typical macroscopic features of necrotising fasciitis. Microbiological investigations revealed Escherichia coli. The lack of massive tissue inflammation, probably due to the neutropenia in our patient, has not been described by other authors. Diagnostic uncertainties owing to masked or uncharacteristic signs in immune compromised patients may lead to a delayed surgical debridement, of which clinicians should be aware. KEYWORDS Necrotising Fasciitis Case reportA 70-year-old man was admitted to our hospital with impaired vision and a downbeat nystagmus. He had a history of anaplastic large-cell lymphoma that was in remission following chemotherapy. However, magnetic resonance imaging (MRI) and a spinal tap on admission confirmed the clinical suspicion of a lymphomatous meningitis. Intrathecal followed by systemic high-dose methotrexate (6640 mg) was administered on day 16 after admission. The patient developed neutropenia on day 20. A mild swelling of the left thigh, with marked pain, fever, tachycardia and tachypnoea were observed on day 23, and the patient was transferred to the intensive care unit (ICU). Laboratory workup revealed a serum C-reactive protein of 438 mg/l and procalcitonin of 33.7 ng/ml. Maximum blood lactate in the first 24 hours after ICU admission was 2.9 mmol/l.An MRI of the left leg showed a slight oedema of the gastrocnemius muscle with no pathological enhancement of the fascia (Fig 1). Antibiotic therapy with imipenem/cilastatine was started and a senior surgeon was immediately consulted, because of the high suspicion of necrotising fasciitis. Surgical exploration of the left leg revealed no typical macroscopic signs of necrotising fasciitis. Only slight bleeding in the soleus and flexor hallucis longus muscles was observed. Tissue biopsy and smears were sent for diagnostic workup and a primary wound closure was performed as the macroscopic features made necrotising fasciitis seem unlikely. Histology showed inflammation and necrosis of the superficial fascia with polymorphonuclear cell infiltration highly suspicious of necrotising fasciitis (Fig 2). Fibrinoid thrombi and necrosis of vessel walls were not observed.The microbiological workup revealed growth of Escherichia coli in the biopsy specimens and the blood cultures. These findings, together with the continuing systemic inflammation, warranted a surgical second look, which was carried out on day 25. Once again, no suspicious signs of necrotising fasciitis were found. Nevertheless, the medial parts of the fascia were excised and the surgical wound was closed. A radical removal of the infected tissue was not certain because of the missing tissue boundaries betwee...