Disseminated extrapulmonary MDRTB in a patient with systemic lupus erythematosus initially masquerading as drug-susceptible tuberculosis

Abstract

Background: Patients with systemic lupus erythematosus (SLE) are at increased risk for opportunistic infections due to impaired cellular immunity inherent to the disease and the immunosuppressive effects of drugs used to treat it. Tuberculosis (TB) is endemic in the Philippines, and multidrug-resistant tuberculosis (MDRTB) is on the rise. SLE patients have a seven-fold higher prevalence of tuberculosis and more commonly develop extrapulmonary tuberculosis (EPTB) more than the general population. Case description: We report a 29-year-old female diagnosed with SLE for seven years who was maintained on daily doses of prednisone 10 mg and hydroxychloroquine 200 mg. With a chronic non-healing ulcer on the right ankle, she had headache, fever, vomiting and photophobia for three weeks. While admitted, she had decreased sensorium and meningeal irritation. Cerebrospinal fluid studies showed lymphocytosis, hypoglycorrhachia, elevated protein level, and positive rifampicin-susceptible TB on Xpert. Patient was started on first-line TB regimen with no improvement of symptoms. Stool was also positive for acid fast bacilli (AFB). Repeat ankle wound aspirate continued to be AFB-positive and culture grew MDRTB. Switching to an MDR anti-TB regimen resulted in marked clinical improvement and recovery. Discussion: Diagnosis and management of TB in SLE is perplexing due to similarities in clinical presentations. This is accounted for by molecular mimicry evidenced by antigen resemblance between mycobacterial cell wall glycolipids and DNA. Moreover, management of MDRTB in SLE is more challenging due to drug toxicities and interactions, and lack of literature. The development of disseminated EPTB MDRTB in our patient may be from the interplay of tuberculosis endemicity, the lupus autoimmunity, and the consequence of immunosuppressive treatment. Fortunately, the TB culture from the repeat debridement of her chronic foot ulcer grew a more clinically-compatible MDRTB, leading to the initiation of a more appropriate treatment regimen. Although this case has a grave prognosis, the patient recovered. Conclusion: To our knowledge, this is the first report of disseminated EPTB (meningitis, musculoskeletal and gastrointestinal) MDRTB in SLE. It is also notable because it demonstrates that MDRTB may appear “drug-susceptible” on TB culture, but should be strongly suspected if AFB smears do not clear, necessitating a repeat TB culture.