Winning Abstracts from the 2011 Medical Student Abstract Competition: The Fruits of Labor: A Baby Boy and IRIS in an HIV-Negative patient
Authors: Akshay Manohar, Kasturba Medical
Jose A. Cortes, MD, FACP
Introduction: The presenting features of any infectious disease are usually the result of host defense mechanisms against the invading pathogens rather than being caused solely by the microorganisms themselves. In an immunocompromised state, clinical features can be subdued while the infecting organisms proliferate unchecked. With sudden re-induction of immunocompetence, there is a seemingly over-active host immune response to a greatly proliferated pathogen population, resulting in a condition called immune reconstitution inflammatory syndrome (IRIS).
Case Presentation: A 34-year old Guyanese woman presented with a tender swelling in the left mandible that appeared 6-weeks after delivering a healthy male neonate. After dental causes were ruled out, the patient was referred to ENT and Infectious Diseases. Her physical examination revealed normal vital signs; a discernable mass/swelling in the left mandible and periorbital area with no lymphadenopathy. CT scans showed a lytic lesion and a mass in both areas. A biopsy revealed necrotizing granulomatous inflammation involving the bone and not confined within the boundaries of a fibrous capsule. Gram, PAS, GMS and AFB stains did not show any organisms. Serologies for Brucella, Bartonella henslae, Bartonella quintana, Coccidioides, Cryptococcus and ELISA for HIV were all negative. A CXR was also negative.
Her PPD test before pregnancy was positive; negative during pregnancy; returning to positive postpartum. AFB cultures were positive for pan-sensitive Mycobacterium tuberculosis. The patient was started on antituberculous therapy with eventual regression of the masses.
Discussion: Pregnancy is an Immunosuppressive state. Tuberculosis is primarily regulated by T-helper-1 (Th1) leukocytes. During pregnancy, Th1 cells' function and quantity are diminished by normal physiologic processes, thereby putting the host in an immunocompromised state allowing the proliferation of M. tuberculosis. The 2008 NYC Department of Health and Mental Hygiene report cites the highest incidence of TB in women ages 25-34 (reproductive age) and men ages 45-54. Immigrants accounted for 76% of the city's TB cases, while they only make up 36% of the population.
Our case illustrates the need to remain cognizant of tuberculosis prevalence in foreign-born reproductive females and the impact pregnancy has on TB. While IRIS is commonly associated with HIV-positive patients who have recently begun HAART regimens, it has also been previously documented in the postpartum population where pregnancy acts as the immunocompromising state. The positive skin test in this case was masked by normal gravid state physiology. From our experience with HIV, PPD testing has lower sensitivity in immunosuppression. We recommend further studies of the incidence/prevalence of tuberculosis in postpartum women and reassessment of current latent tuberculosis diagnosing methods in pregnant women at risk that may evade recognition by standard tuberculin testing.