SAT597 Pituitary Abscess Growing Serratia Marcescens With Associated Clivus Osteomyelitis
Authors: Brown Sean , Milosavljevic Jovan , Chai Jiani , Wong Beatrice Y 
Published: October 2023

Disclosure: S. Brown: None. J. Milosavljevic: None. J. Chai: None. B.Y. Wong: None.

Background: Pituitary abscesses are a rare etiology for pituitary lesions (0.2%-1.1%). Up to 60% of abscesses do not have an obvious source of infection. Pituitary abscesses can develop from the spread of local infection (usually the sphenoid sinus or cavernous sinus). Commonly isolated organisms of pituitary abscesses are gram positive cocci (Staphylococcus and Streptococcus) or gram negative bacilli (E. coli, Neisseria, and Corynebacterium). We present a case of a pituitary abscess growing Serratia marcescens with associated clivus osteomyelitis. Clinical Case: A 26-year-old woman with a history of recurrent left ear infections presented with right eye pain, sixth cranial nerve palsy and headaches. Brain MRI revealed 1.2 x 0.9 x 1.2 cm septated, cystic-appearing, rim-enhancing lesion originating from the sella, exerting mild pressure on the optic chiasm and infiltrating the right cavernous sinus. Contrast-enhanced CT scan revealed sclerotic and erosive changes concerning for clivus osteomyelitis and petrous apicitis. Hormonal evaluation demonstrated panhypopituitarism with undetectable cortisol (&lt;1.0 µg/dL, n = 4-20 µg/dL), low ACTH (2.8 pg/mL, n = 7.2-63.3pg/mL), low-normal FT4 (0.6 ng/dL, n = 0.6-1.5ng/dL), low-normal TSH (0.32 µU/mL, n = 0.3-4.2µU/mL), undetectable estradiol (&lt;25 pg/mL, n = 10-400pg/mL), low FSH (4.1 mIU/mL, n = &lt;20 mIU/mL), low LH (0.5 mIU/mL, n = &lt;10 mIU/mL), elevated prolactin (79 ng/mL, n&lt;25ng/mL), and normal IGF-1 (192 ng/mL, n = 63-373ng/mL). Blood cultures, HIV testing, hepatitis serologies, Aspergillus galactomannan and cryptococcal antigen were negative. Replacement with hydrocortisone and levothyroxine was initiated, as well as empiric treatment with ceftriaxone, vancomycin, and metronidazole. Patient then underwent trans-sphenoidal evacuation of the sellar abscess. Specimen cultures grew Serratia marcescens. Post-operatively, she developed arginine vasopressin (AVP) deficiency and was started on desmopressin. Her symptoms and sixth nerve palsy resolved after surgery, and she was discharged with hormone replacements and a 6-week course of ceftriaxone. Conclusion: While other Enterobacteriaceae have previously been isolated from pituitary abscesses (including E. coli, Citrobacter, Salmonella, Proteus and Klebsiella), our case demonstrates, to the best of our knowledge, the first case of Serratia isolated from a pituitary abscess. Serratia is considered to be an opportunistic pathogen, although this patient had no identifiable risk factors for immunosuppression. Also, pituitary abscesses commonly spread from local infections. However, the source of infection in this case is likely the clivus osteomyelitis, which to the best of our knowledge, also has never been reported. In summary, this case differs from other reported cases due to the pituitary abscess growing Serratia with a potential source from the clivus osteomyelitis.

Presentation: Saturday, June 17, 2023