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Open access

Karen Decaestecker, Veerle Wijtvliet, Peter Coremans and Nike Van Doninck

Summary

ACTH-dependent hypercortisolism is caused by an ectopic ACTH syndrome (EAS) in 20% of cases. We report a rare cause of EAS in a 41-year-old woman, presenting with clinical features of Cushing’s syndrome which developed over several months. Biochemical tests revealed hypokalemic metabolic alkalosis and high morning cortisol and ACTH levels. Further testing, including 24-hour urine analysis, late-night saliva and low-dose dexamethasone suppression test, confirmed hypercortisolism. An MRI of the pituitary gland was normal. Inferior petrosal sinus sampling (IPSS) revealed inconsistent results, with a raised basal gradient but no rise after CRH stimulation. Additional PET-CT showed intense metabolic activity in the left nasal vault. Biopsy of this lesion revealed an unsuspected cause of Cushing’s syndrome: an olfactory neuroblastoma (ONB) with positive immunostaining for ACTH. Our patient underwent transnasal resection of the tumour mass, followed by adjuvant radiotherapy. Normalisation of cortisol and ACTH levels was seen immediately after surgery. Hydrocortisone substitution was started to prevent withdrawal symptoms. As the hypothalamic–pituitary–axis slowly recovered, daily hydrocortisone doses were tapered and stopped 4 months after surgery. Clinical Cushing’s stigmata improved gradually.

Learning points:

  • Ectopic ACTH syndrome can originate from tumours outside the thoracoabdominal region, like the sinonasal cavity.

  • The diagnostic accuracy of IPSS is not 100%: both false positives and false negatives may occur and might be due to a sinonasal tumour with ectopic ACTH secretion.

  • Olfactory neuroblastoma (syn. esthesioneuroblastoma), named because of its sensory (olfactory) and neuroectodermal origin in the upper nasal cavity, is a rare malignant neoplasm. It should not be confused with neuroblastoma, a tumour of the sympathetic nervous system typically occurring in children.

  • If one criticises MRI of the pituitary gland because of ACTH-dependent hypercortisolism, one should take a close look at the sinonasal field as well.

Open access

Carlos Tavares Bello, Francisco Sousa Santos, João Sequeira Duarte and Carlos Vasconcelos

Summary

Central diabetes insipidus (DI) is a rare clinical entity characterized by low circulating levels of antidiuretic hormone (ADH) presenting with polyuria and volume depletion. Pituitary surgery is the most common cause of central DI in adults. Pituitary and hypothalamic disease, particularly invasive neoplasms, rarely cause DI, being idiopathic cases responsible for the majority of non-surgical cases. HIV patients, especially those with poor virulogical control, are prone to the development of CNS neoplasms, particularly lymphomas. These neoplasms usually become manifest with mass effects and seizures. Central DI and hypopituitarism are uncommon initial manifestations of primary CNS lymphomas. The authors describe the case of 29-year-old female, HIV-positive patient whose CNS lymphoma presented with DI.

Learning points:

  • Central diabetes insipidus has multiple causes and central nervous system lymphomas are not often considered in the differential diagnosis due to their low prevalence.

  • Accurate biochemical diagnosis should always be followed by etiological investigation.

  • The HIV population is at risk for many neoplasms, especially CNS lymphomas.

  • New-onset polyuria in an HIV-positive patient in the absence of focal neurological signs should raise the suspicion for a central nervous system process of neoplastic nature.

  • This clinical entity usually constitutes a therapeutical challenge, often requiring a multidisciplinary approach for optimal outcome.

Open access

Verena Schwetz, Felix Aberer, Claudia Stiegler, Thomas R Pieber, Barbara Obermayer-Pietsch and Stefan Pilz

Summary

Cushing's syndrome (CS) due to ectopic ACTH production accounts for about 10% of all types of CS and is frequently associated with metabolic alkalosis. Treatment of CS involves surgical resection and/or medical therapy to control hypercortisolism. We present the case of an 80-year-old woman affected by CS due to an unknown cause. The patient had severe metabolic alkalosis with refractory hypokalemia. To treat the underlying CS, fluconazole was initiated due to unavailability of ketoconazole. In spite of markedly decreasing cortisol levels, metabolic alkalosis persisted. Treatment of metabolic alkalosis with acetazolamide was thus initiated and pH levels successfully lowered. This case report shows that hypercortisolism can be effectively treated with fluconazole in cases where ketoconazole is unavailable or not tolerated and that persistent severe metabolic alkalosis caused by glucocorticoid excess can be safely and successfully treated with acetazolamide.

Learning points

  • Hypercortisolism can be effectively treated with fluconazole where ketoconazole is unavailable or not tolerated.

  • Glucocorticoid excess can cause severe metabolic alkalosis.

  • Persistent severe metabolic alkalosis can be safely and successfully treated with acetazolamide.

Open access

Siew Hui Foo and Shahada A H Sobah

Summary

Hypopituitarism is a rare presentation of Burkitt's lymphoma (BL). The purpose of this report is to present a case of BL presenting with panhypopituitarism and to review other case reports of lymphoma presenting with pituitary dysfunction to highlight the distinguishing features of these cases from other benign aetiologies of pituitary dysfunction such as non-functioning pituitary adenomas. We reviewed a total of 11 cases of lymphoma presenting with pituitary dysfunction published from 1998 to 2013 including the present case. The demographics, clinical presentations, laboratory features, radiological findings, histological diagnosis, treatment administered and outcomes were described. Of the total number of patients, 45.5% of the cases had diffuse large B-cell lymphoma while 27.3% had BL. Anterior pituitary dysfunction was more common than posterior pituitary dysfunction at presentation. The other common associated presenting symptoms were painful ophthalmoplegia, cranial nerve palsies and constitutional symptoms. Hypothalamic–pituitary abnormalities were often demonstrated radiologically to be associated with cavernous sinus and/or stalk involvement. All patients who completed immunochemotherapy responded haematologically. Pituitary dysfunction also improved in most cases although the recovery tended to be partial. In conclusion, a high index of suspicion of underlying malignancy, such as lymphoma, should be present in patients presenting with acute pituitary dysfunction associated with painful ophthalmoplegia, rapidly evolving neurological features, radiological features atypical of a pituitary adenoma and constitutional symptoms. An early diagnosis is essential as prompt initiation of definitive therapy will induce disease remission and recovery of pituitary dysfunction.

Learning points

  • Hypopituitarism may be the presenting symptom of lymphoma in the absence of associated overt symptoms or signs of a haematological malignancy resulting in delay in diagnosis and institution of treatment.

  • Pituitary dysfunction due to tumour infiltration has a greater tendency to involve the posterior pituitary and infundibulum resulting in diabetes insipidus and hyperprolactinaemia compared with a non-functioning pituitary adenoma.

  • The common associated symptoms of hypopituitarism due to lymphoma infiltration of the hypothalamic–pituitary system include painful ophthalmoplegia, cranial nerve palsies and constitutional symptoms.

  • Radiological abnormalities of the hypothalamic–pituitary region are usually present and often associated with cavernous sinus or stalk involvement.

  • With early institution of definitive treatment, both haematological response and improvement of pituitary dysfunction are expected although the reversal of hypopituitarism tends to be partial and delayed.

  • A high index of suspicion of underlying malignancy such as lymphoma should be present in patients presenting with acute pituitary dysfunction associated with painful ophthalmoplegia, radiological features atypical of pituitary adenomas and constitutional symptoms to enable early diagnosis and prompt initiation of definitive therapy.