A case of pituitary abscess presenting without a source of infection or prior pituitary pathology

Pituitary abscess is a relatively uncommon cause of pituitary hormone deficiencies and/or a suprasellar mass. Risk factors for pituitary abscess include prior surgery, irradiation and/or pathology of the suprasellar region as well as underlying infections. We present the case of a 22-year-old female presenting with a spontaneous pituitary abscess in the absence of risk factors described previously. Her initial presentation included headache, bitemporal hemianopia, polyuria, polydipsia and amenorrhoea. Magnetic resonance imaging (MRI) of her pituitary showed a suprasellar mass. As the patient did not have any risk factors for pituitary abscess or symptoms of infection, the diagnosis was not suspected preoperatively. She underwent transsphenoidal resection and purulent material was seen intraoperatively. Culture of the surgical specimen showed two species of alpha hemolytic Streptococcus, Staphylococcus capitis and Prevotella melaninogenica. Urine and blood cultures, dental radiographs and transthoracic echocardiogram failed to show any source of infection that could have caused the pituitary abscess. The patient was treated with 6weeks of oral metronidazole and intravenous vancomycin. After 6weeks of transsphenoidal resection and just after completion of antibiotic therapy, her headache and bitemporal hemianopsia resolved. However, nocturia and polydipsia from central diabetes insipidus and amenorrhoea from hypogonadotrophic hypogonadism persisted. LEARNING POINTS: Pituitary abscesses typically develop in patients who have other sources of infection or disruption of the normal suprasellar anatomy by either surgery, irradiation or pre-existing pathology; however, they can develop in the absence of known risk factors. Patients with pituitary abscesses typically complain of headache, visual changes and symptoms of pituitary hormone deficiencies. As other pituitary neoplasms present with similar clinical findings, the diagnosis of pituitary abscess is often not suspected until transsphenoidal resection is performed. Prompt surgical and medical treatment of pituitary abscess is necessary, which typically results in improvement in headache and visual changes; however, pituitary hormone deficiencies are typically often permanent.