Background: Prolactin is a well-known hormone that mainly functions as a milk producer. Its secretion by lactotroph cells in the pituitary gland (anterior pituitary) is under regulation by different effectors, mainly by Dopamine. However, under non-physiologic circumstances, Prolactin can be over secreted (hyper-prolactinemia) either due to primary (such as pituitary adenoma) or secondary (such as hypothyroidism, infections and systemic diseases) causes. Since prolactin has actions on glucose and lipid metabolisms, hyper-prolactinemia can result in insulin resistance and worsening of lipid profile. In case of prolactinoma, Prolactin can be co-secreted with Growth Hormone in 25% of cases (since lactotroph cells as well as somatotroph cells share common genetic origin), which can have a detrimental additive effect on insulin sensitivity and lipid profile.
Case description: We describe a case of a young male patient with background of type 2 diabetes mellitus (T2DM) (which was not well controlled on oral hypoglycemic agents) and dyslipidemia (which was controlled with Atorvastatin) presented with progressive nausea, vomiting, dizziness and abdominal pain and was admitted initially as a case of DKA. After induction of therapy, the patient was stabilized but then his mental status deteriorated significantly. Computerized Tomography (CT) of the head revealed a giant pituitary mass. Hormonal workups were immediately sent which showed markedly elevated prolactin (PRL) level and slightly elevated growth hormone level as well as IGF-1. The elevation of PRL along with the findings of Magnetic Resonance Imaging (MRI) of pituitary gland, confirmed the diagnosis of giant invasive prolactinoma, which explained his insulin resistance and therefore his presentation.
Conclusion: DKA is a rare presentation of pituitary prolactinoma and should be considered if occurred in a patient with co-existing CNS manifestations.