A 22-year-old woman, resident of Acapulco, Mexico, presented to our unit with a two-month clinical picture of headache, incoherent language, aggressive behavior, inappropriate conducts of disinhibition, and visual-auditory hallucinations. The previous day, the patient had gradually developed a diminished state of awareness. Her medical history was unremarkable. She had two uncomplicated previous pregnancies. Her mother denied any animal contact, recent traveling, ingestion of drugs, or exposure to toxics. She referred a lack of water and food intake in the previous days.
On physical examination, her blood pressure was normal, and she was tachycardic with a weak pulse, dry mucous membranes, and prolonged capillary refill time. In the neurological sphere, she was disoriented and presented retrograde amnesia, impairment in judgment, and loss of abstract thinking. Her chest X-ray and head computed tomography (CT) were normal. Laboratory results revealed severe hypernatremia (Na 180 mEq/L) and acute kidney injury (AKI) (measured creatinine 2 mg/dl-baseline creatinine 0.6 mg/dl). Serum electrolytes, liver tests, blood count, urinalysis, and toxicologic screen were normal. Her spot urinary electrolytes showed a urinary sodium of 20 mEq/L, with a fractional excretion of sodium (FeNa) of 0.5% suggesting hypovolemia. Her calculated water deficit was of 7.5 liters. However, her calculated electrolyte-free water excretion was of 805 ml within a 24-hour urinary volume of 1,000 ml, a value that was inappropriately elevated.
We initiated treatment with enteral administration of free water and hypotonic intravenous solutions for restitution of intravascular volume. During her hospital stay, the patient presented a partial clinical response, with optimization of volemia and resolution of (AKI). A new electrolyte profile showed persistence of hypernatremia (Na 157 mEq/L) and mild hypokalemia (K 3.2 mEq/L). She had a urinary sodium level of 8 mEq/L, with a calculated urine osmolarity of 85 mEq/L, in the context of a 24-hour urinary volume of 4 liters and electrolyte-free water excretion of 3.3 liters. The documented aqueous polyuria and hypernatremia suggested diabetes insipidus. The water deprivation test, that is normally the next step in the diagnosis, was contraindicated, so we ordered a brain magnetic resonance imaging (MRI), which showed a pituitary stalk lesion with chiasmatic and hypothalamic extension (Figure 1(a)).
Treatment with desmopressin was initiated, with progressive normalization of her sodium level, urinary volume, and volemia status (Table 1) (Figure 2). The hormonal profile was compatible with panhypopituitarism, so we initiated treatment with thyroid and glucocorticoid hormones. The cerebrospinal fluid (CSF) analysis showed an elevated protein level of 75 mg/dl, normal glucose, a cell count of zero, and negative Gram and India ink stains. An electroencephalogram documented diffuse cerebral dysfunction without the epileptiform activity. Her blood, urine, CSF, and bone marrow cultures were all negative. A CSF polymerase chain reaction (PCR) for the detection of viral agents and Mycobacterium tuberculosis was negative. The determination of anti-N-methyl-D-aspartate (NMDA) receptor antibodies in CSF was positive. Diverse imaging studies such as thoraco-abdominopelvic CT, endovaginal ultrasound, and whole-body scintigraphy showed no significant abnormalities.
Considering the characteristic clinical behavior of the patient, we decided to order a stereotactic biopsy of the pituitary mass. The pathology report revealed noncaseating granulomatous inflammation and gliosis (Figures 1(b)-1(d)). The periodic acid Schiff stain (PAS), Ziehl-Neelsen stain, and Grocott stain of the tissue were all negative. Immunohistochemical markers CD1a and langerin to rule out Langerhans cell histiocytosis were negative. Serological tests for Epstein-Barr, hepatitis B, hepatitis C, cytomegalovirus, toxoplasma, and Brucella spp were all negative. A PCR for the detection of Rickettsia spp, Ehrlichia spp, Anaplasma spp, and Borrelia burgdorferi were also negative. A nested PCR in biopsy tissue for the detection of Mycobacterium tuberculosis was also negative. The angiotensin converting enzyme serum level was in the normal range.
Based on the pathology findings and the 2018 consensus diagnostic criteria, we concluded the final diagnosis of isolated neurosarcoidosis. She received treatment with prednisone and showed significant improvement of the neuropsychiatric symptoms. The patient was discharged from our unit to continue ambulatory treatment; however, she was lost at the follow-up.