Clinical , hormonal and radiological features of partial Sheehan ’ s syndrome : an Indian experience

Objective: The objective of this study was to describe clinical presentation, hormonal profile and imaging characteristics of 21 patients with partial Sheehan’s syndrome. Subjects and methods: This prospective study was carried out over a period of six years (2008-2013). The evaluation of patients included clinical assessment, hormone estimations and contrast enhanced magnetic resonance imaging of pituitary. Results: We documented preservation of gonadotroph, corticotroph and lactotroph function in 71.4, 61.9, and 9.5% of patients respectively. Conclusion: To conclude some of the pituitary functions can be preserved in Sheehan’s syndrome and this has important implications from the treatment and long term morbidity point of view. Arch Endocrinol Metab. 2016;60(2):125-9


INTRODUCTION
P ostpartum pituitary necrosis results from severe hypotension or shock secondary to blood loss at the time of childbirth (1).Sheehan's syndrome (SS) is the most common cause of hypopituitarism in women from developing countries (2).Improvement in the ob stetric care has considerably decreased the prevalence of SS in western world (3).An epidemiological study from India (Kashmir) has documented a prevalence of around 3.1% in adult women (4).Though SS is rare in the west, recently the disease has been reported from some developed countries.Sheehan's syndrome was the sixth common cause of adult growth hormone (GH) deficiency comprising of 3.1% of total patients of adult hypopituitarism, who were administered GH (5).The largest series of patients with SS seen over a period of more than two decades was published recently (6).The clinical presentation of hypopituitarism in SS va ries from subtle symptoms to severe hypocortisol crisis.The extent of hypopituitarism (the number of trophic hormones deficient) and the severity of deficiency of a given hormone are variable.The detailed description of preservation of anterior pituitary functions in these patients is limited to case reports (7).With limited data available on clinical profile of partial SS, we present a large series of such patients from North Indian region.

SUBJECTS AND METHODS
This prospective study was carried at an endocrine center in North India over a period of six years (2008 2013).The study was approved by institutional ethical committee and an informed consent was obtained from each subject.Twenty one patients fulfilled the criteria for partial SS and were included in the study.The diag nosis of SS was based on: (a) history of postpartum he morrhage (PPH) or failure of lactation and/or amenor rhea following last child birth; (b) deficiency of more than one anterior pituitary hormone and (c) empty sella on pituitary MRI (2).Partial SS was defined as hypopi tuitarism following an obstetric insult with preservation of one or more of five trophic hormone producing cell lines i.e. lactotroph, somatotroph, corticotroph, thyro troph and gonadotroph with empty sella on MR ima ging.General physical and systemic examination was performed on all subjects.
The clinical assessment was specifically focused on seeking the findings suggestive of deficiency of various pituitary hormones.The patients were admitted in the Partial Sheehan's syndrome Arch Endocrinol Metab.2016;60/2 hospital and evaluated according to a predefined pro tocol.Fasting blood samples were obtained for com plete blood count, liver and kidney function tests, elec trolytes and glucose.Hormone estimations included serum thyroid stimulating hormone (TSH), total thy roxine (T4), folliclestimulating hormone (FSH), lu teinizing hormone (LH), cortisol, prolactin (PRL) and GH.A baseline sample was drawn for estimation of all anterior pituitary hormones, serum cortisol and total serum T4.Patients were put on injectable hydrocorti sone and oral thyroxine.After stabilizing and correcting the acute metabolic derangements like hypoglycemia, hyponatremia, hypokalemia and dehydration, patients were discharged on oral thyroxine (50-100 µg/day), prednisolone (5-7.5 mg/day) and were followed monthly.Corticosteroids were withdrawn on follow up in women with basal cortisol of 18 µg/dL or more.Women younger than 40 years were also administered cyclic estrogen/progesterone pills in case of loss of gonadotroph function.After documenting euthyroid state, women with corticotroph involvement were put on oral hydrocortisone in place of prednisolone.Hy drocortisone was stopped for two days and insulin toler ance test (ITT) was performed to assess for lactotroph, somatotroph and corticotroph function; magnetic reso nance imaging (MRI) sella was also done in the same admission.The preservation of pituitary function was defined as: resumption of menstrual cycles after deliv ery with normal basal gonadotropins for gonadotrophs, a serum cortisol of 18 µg/dL or more, either basally or at any time during the ITT for corticotrophs, nor mal lactation in puerperium and an increase in serum prolactin of at least 100% over the basal value on ITT for lactotrophs, normal baseline T4 and TSH for thy rotrophs, and a peak serum GH of least 3 µg/l on ITT for somatotrophs Serum concentrations of T4, TSH, LH, FSH, PRL, and GH were measured by immuno radiometric assay (IRMA) using commercially available kits (Siemens Medical solutions, Los Angles USA, CA 900456900).Serum cortisol was measured by radio immunoassay (RIA) using commercially available kits (Diasorin Stillwater, Minnesota 550820285 USA).

RESULTS
A total of 21 patients qualified for the definition of par tial SS.Mean age of the patients was 39.3 ± 8.4 years with a parity ranging from 14 deliveries.The mean time since last delivery was 11.81 ± 8.48 years (range 130 years).All but three patients had PPH at the time of last delivery and 14 had received blood transfusion.Two patients lactated normally.Twelve patients resumed reg ular menstrual cycles, another 3 patients having oligo menorrhea after last delivery, one of whom had a suc cessful pregnancy subsequently.Table 1 gives the details of clinical features, trophic hormone deficiencies and MRI findings of all the 21 patients.All had low serum T4 with inappropriately normal TSH in 16 and mildly increased TSH in five patients.Insulin tolerance test re vealed subnormal GH response in all the patients and subnormal prolactin response in all except two patients; 10 of 21 patients had a normal cortisol response to ITT.One patient had a normal basal cortisol and in one, ITT could not be done, instead short synacthene test was done which confirmed a normal cortisol response.Table 2 gives the details of hormonal analysis in all the wom en with partial Sheehan's syndrome.Overall, 85% of women had history of PPH and 66% had received blood transfusion.Lactation failure was seen in 90% of women, corticotroph failure in 38% of the women, and gonado troph failure in 28% of women.All these women had somatotroph and thyrotroph failure.Contrast enhanced MRI revealed evidence of empty sella in all the patients.All the patients are on replacement treatment appropri ate for the deficiency of their pituitary hormones.

DISCUSSION
The diagnosis of SS in these patients was based on PPH, lactation failure, trophic hormone deficiency and presen ce of empty sella on MRI.In recent times many series of cases with SS have been published and the presentation of the cases has been variable (6,810).Here we present the clinical, hormonal and radiological details of a se ries of 21 patients with partial SS.In the present series, all patients had growth hormone and thyroid hormone deficiency.Inapprapriately normal or increased TSH se cretion has been demonstrated in women with SS.Af ter the development of pituitary necrosis, initially TSH levels decrease which results in decreased T4 which in turn stimulates TSH production and secretion by the remaining thyrotrophs.Low levels of cortisol and gro wth hormone also contribute to increase in TSH release in these patients.The increased TSH produced has low intrinsic bioactivity and decreased metabolic clearance (11,12).Prolactin deficiency was seen in 19    tuitary gland and are damaged predominantly during the ischemic necrosis (13).There is a consensus among different series that GH deficiency is a universal finding in SS (2,79,14).Normal lactation and preservation of lactotroph function has been reported in different se ries.One study reported normal lactation in 30% yet all had GH and prolactin deficiency on dynamic testing (9).In yet another series, 2 out of 28 patients had nor mal lactation and both had a normal prolactin response to ITT (8).Previously prolactin deficiency was reported in 85.2% of women with SS on ITT (5).In a recent large series of 114 patients, 37% of women had normal lactation which included 6% of women having a blunted response to TRH test (6).In the present series 9.5% of women had normal lactation and a normal prolactin response to ITT.There is some discordance between prolactin deficiency documented biochemically and failure of lactation.It has been reported that lactation can be normal even in women with lactotroph failure documented on dynamic tests (10).Rarely, lactotroph function may recover after its initial loss (15).The most consistent finding in SS is the loss of somatotroph and thyrotroph function; though the loss of somatotroph function is universal, there are varying reports about involvement of thyrotroph function.Several previous series reported thyrotroph failure in 90% of patients (6,8,9,13) and one reported it in all the patients (8).All of our patients had thyrotrophs failure.Our data are consistent with recent Indian studies, wherein most of the patients with SS have thyrotroph failure (7,14,16).Preservation of gonadotroph function in women with SS has been widely reported in the literature.Loss of go nadotroph function has been reported in all the patient series from Turkey (6,8,9).On the other hand Indian data reveal that preservation of gonadotroph function and subsequent pregnancy is not an uncommon pheno menon (8,1720).We previously reported preservation of gonadotroph function in 30% of women with partial SS (7), and 71% of our patients in the present series had pre served gonadotrophs.There seems to be no explanation for this disparity between Indian and Turkish patients.
Preservation of corticotroph function has important implication on the long term management of women with SS.Corticotroph involvement has been reported in 50100% of women in different series (6,7,9).In the present series, 62% of women had preservation of corti cotroph function.Corticotroph failure is the main cau se of hypoglycemia and is easily correctable with glu cocorticoid administration; glucocorticoid replacement in presence of severe hypothyroidism predisposes them to severe psychosis (21).Preservation of corticotro ph function spares these women from the undesirable effects of exogenous glucocorticoids.Several mecha nisms have been invoked to explain the sparing of cor ticotrophs.In human pituitary corticotrophs comprise around 1020% of cells and are most numerous around mid sagittal region, with some of the cells concentrated in lateral wings and zona intermedia.Zona Interme dia is situated between anterior and posterior pituita ry, and some of these cells extend into the posterior pituitary which is known as basophilic invasion.Mid sagital region is least damaged during pituitary infarc tion.Because of dual blood supply to posterior pitui tary, it is likely that these cells escape damage and will be responsible for preservation of some of corticotroph function (22).None of the patients in the present se ries had involvement of posterior pituitary function in the form of polyuria.Diabetes insipidus is quite rare in these patients, though subtle features of posterior pituitary involvement have been reported (23).Table 3 summarizes the anterior pituitary involvement in re ported series of patients with SS.We conclude that in areas where SS is still common, atypical and partial presentation are also quite common.Though GH and TSH deficiencies are universal in SS, gonadotropin and corticotropin secretion may be pre served in these patients.The preservation of ACTH se cretion, in particular, has important therapeutic impli cations given the difficulties and the risks of long term glucocorticoid replacement; hence every effort should be made to assess the corticotroph function.
Contributions: the authors alone are responsible for the content and writing of the paper.
Disclosure: no potential conflict of interest relevant to this article was reported.

Table 1 .
out of 21 patients.Anatomically lactotroph and somatotroph cells are situated in the lower and lateral regions of the pi Clinical features, trophic hormone deficiencies and MR imaging features of patients PPH: post partum hemorrhage; BT: blood transfusion; LTF: lactotroph failure; TTF: thyrotroph failure; STF: somatotroph failure; CTF: corticotroph failure; GTF: gonadotroph failure; MRI: magnetic resonance imaging; ES: empty sella.

Table 3 .
Summary of loss of anterior pituitary functions (%) in women with Sheehan's syndrome