Diagnosis and Treatment > Signs and Symptoms
Search for other papers by Natassia Rodrigo in
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Summary
This case illustrates the exceedingly rare phenomenon of transient diabetes insipidus, in association with pre-eclampsia, occurring in the post-partum period following an in vitro fertilisation pregnancy, in an otherwise well 48-year-old lady. Diabetes insipidus can manifest during pregnancy, induced by increased vasopressinase activity secreted by placental trophoblasts and usually manifests in the third trimester. This presentation elucidates not only the intricate balance between the physiology of pregnancy and hormonal homeostasis, but also the importance of post-partum care as the physiological changes of pregnancy still hold pathological potential in the weeks immediately following delivery.
Learning points:
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Diabetes insipidus (DI) is a rare complication of pregnancy occurring in 1 in 30 000 pregnancies.
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It is associated with excessive vasopressinase activity, secreted by placental trophoblasts, which increases the rate of degradation of anti-diuretic hormone.
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It is responsive to synthetic desmopressin 1-deanimo-8-d-arginine vasopressin as this form is not degraded by placental vasopressinase.
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Vasopressinase is proportional to placental weight, which is increased in pregnancies conceived with assisted reproductive techniques including in vitro fertilisation.
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Vasopressinase-induced DI is associated with pre-eclampsia.
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Search for other papers by Adam Roberts in
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Summary
Immune checkpoint inhibitors are the mainstay of treatment for advanced melanoma, and their use is being increasingly implicated in the development of autoimmune endocrinopathies. We present a case of a 52-year-old man with metastatic melanoma on combination nivolumab and ipilumimab therapy who developed concurrent hypophysitis, type 1 diabetes mellitus (T1DM) and diabetes insipidus. He presented prior to third cycle of combination treatment with a headache, myalgias and fatigue. Biochemistry and MRI pituitary confirmed anterior pituitary dysfunction with a TSH: 0.02 mU/L (0.5–5.5 mU/L), fT4: 5.2 pmol/L (11–22 pmol/L), fT3: 4.0 pmol/L (3.2–6.4 pmol/L), cortisol (12:00 h): <9 nmol/L (74–286 nmol/L), FSH: 0.7 IU/L (1.5–9.7 IU/L), LH: <0.1 IU/L (1.8–9.2 IU/L), PRL: 1 mIU/L (90–400 mIU/L), SHBG: 34 nmol/L (19–764 nmol/L) and total testosterone: <0.4 nmol/L (9.9–27.8 nmol/L). High-dose dexamethasone (8 mg) was administered followed by hydrocortisone, thyroxine and topical testosterone replacement. Two weeks post administration of the third cycle, he became unwell with lethargy, weight loss and nocturia. Central diabetes insipidus was diagnosed on the basis of symptoms and sodium of 149 mmol/L (135–145 mmol/L). Desmopressin nasal spray was instituted with symptom resolution and normalization of serum sodium. Three weeks later, he presented again polyuric and polydipsic. His capillary glucose was 20.8 mmol/L (ketones of 2.4 mmol), low C-peptide 0.05 nmol/L (0.4–1.5 nmol/L) and HbA1c of 7.7%. T1DM was suspected, and he was commenced on an insulin infusion with rapid symptom resolution. Insulin antibodies glutamic acid decarboxylase (GAD), insulin antibody-2 (IA-2) and zinc transporter-8 (ZnT8) were negative. A follow-up MRI pituitary revealed findings consistent with recovering autoimmune hypophysitis. Immunotherapy was discontinued based on the extent of these autoimmune endocrinopathies.
Learning points:
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The most effective regime for treatment of metastatic melanoma is combination immunotherapy with nivolumab and ipilumimab, and this therapy is associated with a high incidence of autoimmune endocrinopathies.
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Given the high prevalence of immune-related adverse events, the threshold for functional testing should be low.
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Traditional antibody testing may not be reliable to identify early-onset endocrinopathy.
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Routine screening pathways have yet to be adequately validated through clinical trials.
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Search for other papers by Philip A Kern in
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Summary
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
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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.
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Patients with pituitary abscesses typically complain of headache, visual changes and symptoms of pituitary hormone deficiencies.
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As other pituitary neoplasms present with similar clinical findings, the diagnosis of pituitary abscess is often not suspected until transsphenoidal resection is performed.
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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.
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Search for other papers by Mette Gaustadnes in
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Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark
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Search for other papers by Judit Denes in
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Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Search for other papers by Jens O L Jørgensen in
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Summary
A patient of Cushing's disease (CD) characterized by a large tumor and only subtle symptoms of hormonal hypersecretion was examined. The patient had a germline variant in the aryl hydrocarbon receptor-interacting protein (AIP) gene. A 50-year-old male presenting with headache was diagnosed with a large pituitary tumor by magnetic resonance imaging (MRI). His visual fields were intact and he exhibited no features of CD. Owing to an exuberant response to synacthen, an overnight dexamethasone suppression test was performed revealing inadequate suppression of plasma cortisol (419 nmol/l). Owing to tumor growth and visual field impairment, he underwent transsphenoidal surgery and developed hypocortisolemia. The pathology specimen revealed a sparsely granulated corticotrope adenoma. Postoperative MRI showed a large tumor remnant. The patient developed skin hyperpigmentation and a synacthen test demonstrated high basal and stimulated cortisol levels; an overnight dexamethasone suppression test showed no suppression (791 nmol/l) and elevated plasma ACTH levels (135 ng/l). A transcranial operation was performed followed by radiotherapy. Two months after radiotherapy, he developed secondary adrenocortical failure. Genetic testing revealed an AIP variant of unknown significance (p.R16H) without loss of the normal AIP allele in the tumor. A literature review showed ten CD patients with AIP gene variants, of whom five (including our case) were p.R16H. CD is occasionally dominated by pituitary tumor growth rather than symptoms of hypersecretion. The particular AIP gene variant identified in our patient is shared by four other reported cases of CD. Future studies are needed to assess whether the reported AIP gene variant is more than just coincidental.
Learning points
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CD is occasionally dominated by pituitary tumor growth rather than symptoms of hypersecretion.
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Resolution of both tumor remnant and hormonal hypersecretion may occur within 2 months after postoperative radiotherapy.
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The particular AIP gene variant identified in our patient is shared by four other reported cases of CD.
