A 64-year-old man with no remarkable past history presented with a raised red lesion over the neck at the site of a prior injury from a tree branch, which had occurred 6 months ago. There was no history of fever or preceding treatment with corticosteroids. He gave history of frequent headaches and pus discharge from the lesion occasionally. He received a course of antibiotics for two months without improvement. The lesion continued to progress and the patient develop scalp fistulas. On physical examination, a solitary 6 x 4 cm subcutaneous well circumscribed lesion in the posterior neck with multiple scalp fistula was seen. There was a pus discharge from the tumefaction and the fistulas and an associated right purulent otorrhoea (Figure 1). Systemic examination was normal. Routine laboratory tests yielded a white blood cells count of 16,600 /mm3 and a C-reactive protein of 88.2 mg/l. A computed tomography (CT) scan of the brain showed a hyper-attenuating lesion of the posterior neck which was uniloculated with a liquid component in its centre.
There was no evidence of osteolysis of the skull. Magnetic resonance imaging (MRI) examination of the brain and the neck showed a nuchal process that enhanced heterogeneously after IV gadolinium associated with a necrotic component. A clinical diagnosis of actinomycosis, deep mycoses or cutaneous tuberculosis was suggested. But the pyogenic associated infection was suspected because of leukocytosis and the high level of C-reactive protein. He was prescribed a 6 g daily of cefazolin and he underwent skin biopsy which showed a mixed inflammatory infiltrate without necrotizing inflammation or evidence of neoplasia or granuloma. Purified protein derivative (PPD) skin test was negative. Fungal, mycobacterial and bacterial cultures showed no growth. Periodic acid-shiff and acid-fast bacilli stains were negative. Serology for candida, aspergillus and retrovirus were all negative. On follow up, the patient reported headaches, poor concentration and blurring of vision. The lesion continue to progress with pus drainage. Fundoscopy revealed papilloedema. A CT scan of the brain done 15 days later showed an enhancing lesion in the occipital lobe with brain oedema, signs of located meningitis and osteolysis of the skull in the occipital region near to the primary lesion (Figure 2). MRI of brain showed superior sagittal sinus thrombosis (Figure 3). The patient underwent one more skin biopsy and excision of the lesion for bacterial, fungal and mycobacterial culture.
On histopathological examination, multiple basophilic filamentous pathogens inside macrophages with dense infiltration by chronic inflammatory cells were seen. These pathogens were periodic acid-shiff positive. A diagnosis of cutaneous nocardiosis was made based on the morphology and the staining properties on biopsy. The patient was started on treatment with sulfamethoxazol SMX (55 mg/kg daily) trimethoprim TMP (10 mg/kg daily) and gentamicin (3 mg/kg daily) for two weeks followed by SMX-TMP for 1 month. The patient was started on anticoagulant therapy followed by oral vitamin K antagonists. He has reported significant improvement and is due for a follow up visit. After nearly four months, the patient presented to the emergency room with high grade fever and an erythematous rash of his trunk and four limbs. A complete blood count revealed a leukocytosis of 19,600/mm3 and an elevated absolute eosinophil count of 700/mm3. His liver function was deranged with levels of aspartate transaminase 60 UI/ml, alanine transaminase 112 UI/ml and total bilirubin 45 mumol/l. Urine microscopy, renal function tests, blood sugar level, chest X-ray and electrocardiogram were all within normal limits. A peripheral blood smear revealed atypical lymphocytes. Skin biopsy confirmed the diagnosis of drug reaction with eosinphilia systemic symptom syndrome caused by SMX-TMP. The treatment was discontinued and the patient was started with doxycycline 200 mg per day for 18 months. He had shown clinical, biochemical and radiological improvement there were no signs of reactivation of Nocardia infection (Figure 4).