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Open access

Ilan Rahmani Tzvi-Ran, Judith Olchowski, Merav Fraenkel, Asher Bashiri and Leonid Barski

Summary

A previously healthy 24-year-old female underwent an emergent caesarean section without a major bleeding described. During the first post-operative days (POD) she complained of fatigue, headache and a failure to lactate with no specific and conclusive findings on head CT. On the following days, fever rose with a suspicion of an obstetric surgery-related infection, again with no evidence to support the diagnosis. On POD5 a new-onset hyponatremia was documented. The urine analysis suggested SIADH, and following a treatment failure, further investigation was performed and demonstrated both central hypothyroidism and adrenal insufficiency. The patient was immediately treated with hydrocortisone followed by levothyroxine with a rapid resolution of symptoms and hyponatremia. Further laboratory investigation demonstrated anterior hypopituitarism. The main differential diagnosis was Sheehan’s syndrome vs lymphocytic hypophysitis. Brain MRI was performed as soon as it was available and findings consistent with Sheehan’s syndrome confirmed the diagnosis. Lifelong hormonal replacement therapy was initiated. Further complaints on polyuria and polydipsia have led to a water deprivation testing and the diagnosis of partial central insipidus and appropriate treatment with DDAVP.

Learning points:

  • Sheehan’s syndrome can occur, though rarely, without an obvious major post-partum hemorrhage.

  • The syndrome may resemble lymphocytic hypophysitis clinically and imaging studies may be crucial in order to differentiate both conditions.

  • Hypopituitarism presentation may be variable and depends on the specific hormone deficit.

  • Euvolemic hyponatremia workup must include thyroid function test and 08:00 AM cortisol levels.

Open access

Shunsuke Funazaki, Hodaka Yamada, Kazuo Hara and San-e Ishikawa

Summary

Lymphocytic hypophysitis (LyH) has been known to be associated with pregnancy. We herein report the case of a 33-year-old woman who underwent vaginal delivery without massive bleeding at 40 weeks of gestation. Because of the presence of headache and terrible fatigue after childbirth, she visited our hospital. Severe hyponatremia (Na, 118 mEq/L) and visual field abnormality was noted upon examination. MRI revealed pituitary enlargement with a swollen pituitary stalk, albeit at low signal intensity. Basal pituitary hormone levels were all reduced and remained low after exogenous administration of hypothalamic-releasing hormones. She was diagnosed with LyH and was started on prednisolone 60 mg/day. A month later, her pituitary function had gradually improved together with a decrease in pituitary enlargement and recovery of her visual field. The dose of prednisolone was gradually reduced and finally withdrawn 27 months later. After prednisolone withdrawal, her pituitary function remained normal despite the absence of any hormonal replacement. A year later, she became pregnant without medication and delivered a second baby without LyH recurrence. Thereafter, her pituitary function has been normal for more than 5 years. Two valuable observations can be highlighted from the case. First, the patient completely recovered from LyH through prompt prednisolone therapy during its initial phase and had almost normal pituitary function. Second, after recovery from LyH, she was able to undergo spontaneous pregnancy and deliver a baby. We believe that reporting incidences of spontaneous pregnancy after complete normalization of pituitary function in patients with LyH is of great significance.

Learning points:

  • Females are more affected by LyH than males given its strong association with pregnancy.

  • LyH possesses characteristic findings on pituitary MRI.

  • Glucocorticoid therapy for LyH has been recommended as an effective treatment.

  • A history of previous pregnancies does not increase the risk of developing AH in subsequent pregnancies.

  • Early induction of high-dose prednisolone was therapeutically effective in treating LyH.

Open access

W K M G Amarawardena, K D Liyanarachchi, J D C Newell-Price, R J M Ross, D Iacovazzo and M Debono

Summary

The granulation pattern of somatotroph adenomas is well known to be associated with differing clinical and biochemical characteristics, and it has been shown that sparsely granulated tumours respond poorly to commonly used somatostatin receptor ligands (SRLs). We report a challenging case of acromegaly with a sparsely granulated tumour resistant to multiple modalities of treatment, ultimately achieving biochemical control with pasireotide. A 26-year-old lady presented with classical features of acromegaly, which was confirmed by an oral glucose tolerance test. Insulin-like growth factor 1 (IGF1) was 1710 µg/L (103–310 µg/L) and mean growth hormone (GH) was >600 U/L. MRI scan showed a 4 cm pituitary macroadenoma with suprasellar extension and right-sided cavernous sinus invasion. She underwent trans-sphenoidal pituitary surgery. Histology displayed moderate amounts of sparsely granular eosinophilic cytoplasm, staining only for GH. Postoperative investigations showed uncontrolled disease (IGF1:1474 µg/L, mean GH:228 U/L) and residual tumour in the cavernous sinus. She received external beam fractionated radiation. Over the years, she received octreotide LAR (up to 30 mg), lanreotide (up to 120 mg) two weekly, cabergoline, pegvisomant and stereotactic radiosurgery to no avail. Only pegvisomant resulted in an element of disease control; however, this had to be stopped due to abnormal liver function tests. Fifteen years after the diagnosis, she was started on pasireotide 40 mg monthly. Within a month, her IGF1 dropped and has remained within the normal range (103–310 µg/L). Pasireotide has been well tolerated, and there has been significant clinical improvement. Somatostatin receptor subtyping revealed a positivity score of two for both sst5 and sst2a subtypes.

Learning points:

  • Age, size of the tumour, GH levels on presentation, histopathological type and the somatostatin receptor status of the tumour in acromegaly should be reviewed in patients who poorly respond to first-generation somatostatin receptor ligands.

  • Tumours that respond poorly to first-generation somatostatin receptor ligands, especially sparsely granulated somatotroph adenomas, can respond to pasireotide and treatment should be considered early in the management of resistant tumours.

  • Patients with membranous expression of sst5 are likely to be more responsive to pasireotide.

Open access

Dominic Cavlan, Shanti Vijayaraghavan, Susan Gelding and William Drake

Summary

A state of insulin resistance is common to the clinical conditions of both chronic growth hormone (GH) deficiency and GH excess (acromegaly). GH has a physiological role in glucose metabolism in the acute settings of fast and exercise and is the only anabolic hormone secreted in the fasting state. We report the case of a patient in whom knowledge of this aspect of GH physiology was vital to her care. A woman with well-controlled type 1 diabetes mellitus who developed hypopituitarism following the birth of her first child required GH replacement therapy. Hours after the first dose, she developed a rapid metabolic deterioration and awoke with hyperglycaemia and ketonuria. She adjusted her insulin dose accordingly, but the pattern was repeated with each subsequent increase in her dose. Acute GH-induced lipolysis results in an abundance of free fatty acids (FFA); these directly inhibit glucose uptake into muscle, and this can lead to hyperglycaemia. This glucose–fatty acid cycle was first described by Randle et al. in 1963; it is a nutrient-mediated fine control that allows oxidative muscle to switch between glucose and fatty acids as fuel, depending on their availability. We describe the mechanism in detail.

Learning points

  • There is a complex interplay between GH and insulin resistance: chronically, both GH excess and deficiency lead to insulin resistance, but there is also an acute mechanism that is less well appreciated by clinicians.

  • GH activates hormone-sensitive lipase to release FFA into the circulation; these may inhibit the uptake of glucose leading to hyperglycaemia and ketosis in the type 1 diabetic patient.

  • The Randle cycle, or glucose–fatty acid cycle, outlines the mechanism for this acute relationship.

  • Monitoring the adequacy of GH replacement in patients with type 1 diabetes is difficult, with IGF1 an unreliable marker.