In retrospect, these infections probably accounted for some of the patient’s previous symptoms. This case clearly illustrates the challenges of timely diagnosis of unusual infections. The differential diagnosis was broad and included opportunistic infections, malignancy and interstitial lung disease. The possibility of an opportunistic infection, including mucormycosis, tuberculosis, actinomycosis and nocardiosis, all having similar appearance on CT, ranked high in the list of possible diagnosis . The presence of mildly enlarged hilar and mediastinal lymph nodes, as found in our patient, is unusual in nocardiosis. This finding, together with radiologic signs suggestive of previous tuberculosis exposure and the clinical presentation of night sweats and weight loss further complicated the differential diagnosis. Pulmonary malignancies and interstitial lung disease, including lupus interstitial pneumonia, non-specific interstitial pneumonia or co-existing sarcoidosis, were also part of the diagnostic spectrum.
Multiple factors contributed to the difficulty of the diagnostic process. First, our patient presented with recurrent acute pulmonary infections with temporary improvement after treatment with antibiotics, mostly fluoroquinolones. Fluoroquinolones have activity against Nocardia farcinica. Second, it took six months to acquire a positive (blood) culture for Nocardia. The microbiological challenge is well described in the literature for nocardiosis and mucormycosis [4, 5]. Third, Pseudomonas aeruginosa was isolated from the BAL and initially deemed responsible for the infection. Other interfering elements were the signs of heart failure and that the infection mimicked a flare-up of SLE . Importantly, disease activity and infection can occur simultaneously .
Isolation of Nocardia in any patient, from any body source, should always be regarded as significant . An aggressive diagnostic strategy that includes BAL and tissue biopsies may significantly improve the outcome .
Rapid identification of infection with Nocardia is crucial, because delayed diagnosis and treatment has an important impact on the prognosis . Because of the evolution to septic shock, ceftriaxone and amikacin were added to our patient’s antibiotic regimen. An optimal antibiotic treatment for nocardiosis is not yet established [2, 10]. Trimethoprim-sulfamethoxazole has been the drug of choice for treatment of nocardiosis for many years [5, 10, 11] but there are several other antibiotics with activity against Nocardia, including ceftriaxone, cefotaxime, amikacin, imipenem, meropenem, linezolid, minocycline, moxifloxacin, levofloxacin, tigecycline and amoxicillin-clavulanic acid . Because there is a difference in antibiotic susceptibility pattern between Nocardia species, identification to the species level and antibiotic susceptibility testing should, like in our case, be undertaken in each patient and treatment should be individualized accordingly . Combination therapy with a second or even a third antibiotic agent in severe cases can be warranted until the susceptibility pattern is known and the clinical condition of the patient improves . The duration of antibiotic therapy is often prolonged to minimize disease relapse (6 to 12 months, and in some cases even longer) [2, 5, 10]. The mortality rate in immunosuppressed patients with pulmonary and/or disseminated Nocardia infection is as high as 65% .
Mucormycosis is a very aggressive invasive fungal disease. When suspected, a biopsy should be obtained whenever possible. Diagnosis requires direct microscopy, histopathology and culturing of clinical specimens . Unfortunately, the pre-mortem diagnostic rate of mucormycosis is extremely low . The mainstay of treatment is surgical debridement and treatment with (liposomal) amphotericin B (at least 5mg/kg/day), or posaconazole (200mg, four times daily) in case of treatment failure with amphotericin B .
A handful of cases of mucormycosis in SLE were reported in the English literature and most of them were disseminated infections with fatal outcome even if adequate therapy with amphotericin B was initiated . Only a few cases of combined disseminated mucormycosis and nocardiosis in immunosuppressed patients have been reported .