 |  a man with fatigue,dec libido,polyuria..
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| Author | 8 Posts |
zaki
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A 35-year-old woman is referred to you for evaluation of a 3-month history of fatigue, diminished libido, polyuria, and polydipsia. For the last month, she has experienced persistent nausea and vomiting. She has had no previous medical illnesses. Physical examination reveals dry skin and sparse pubic and axillary hair. Visual fields are intact. Chest radiograph is normal. Laboratory studies reveal an elevated serum sodium level of 148 meq/L and normal serum glucose and calcium levels, along with the passage of 4000 mL of urine per day with a specific gravity of 1.003. Evaluation of pituitary function reveals marked reduction in basal hormone levels and inadequate responses to stimulation for growth hormone, prolactin, thyrotropin, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone (ACTH), and cortisol. Magnetic resonance imaging of the brain shows an isointense sellar mass involving the pituitary stalk, with loss of the hyperintense posterior pituitary signal. After replacement therapy with glucocorticoids, thyroxine, and DDAVP (desmopressin), to which the patient had a salutary response, transsphenoidal pituitary surgery was performed.
The most likely diagnosis is:
A) Pituitary adenoma
B) Metastatic carcinoma to the pituitary gland
C) Neurosarcoidosis
D) Lymphocytic hypophysitis
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Maverick
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| gballarino
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In the subject, it says the case´s about a "man" :!: , but I´ll go as it says in the history (woman).
All of the options are potential causes of panhypopituitarysm. So I guess the question is about discarding the "less-likely" options. :?
d) lymphocytic hypofysitis: described mainly in pregant or post-partum woman, with MRI evidence of an adenoma-like mass, and mildly elevated prolactin levels. History doesn´t say anything about pregnancy, so... this is my first pass.
c) neurosarcoidosis: though sarcoidosis is a systemic disease, it mainly affects the lungs, thus neurosarcoidosis with a normal chest film is highly unlikely. Lymph node, skin, liver and eye follow the lung in frequency of involvement. CNS is way behing. So, i wouldn´t choose this option.
b) Metastatic carcinoma is more frequent in the posterior pituitary; rarely, stalk involvement results in anterior pituitary insuficiency. Mtt. Ca. can be confused with an agresive adenoamtous lession, and diferential diagnosis would require histologic studies; however, this is a previously healthy young woman, and an adenoma is more likely. Loss of the normal bright can be caused by either destruction of posterior pituitary (which would support the diagnosis of metastatic carcinoma) or by stalk compresion. Tought not very likely, she could have an occul breast carcinoma.
a) I choose option A. Nonfunctioning adenomas are the most common type of pituitary adenomas and are usually macroadenomas at the time of diagnosis. Some things don´t quite fit, however. Pituitary adenomasin the anterior pituitary, though they can involve the stalk. Another loose end is the IRM findings. Pituitary adenomas usually give an hypointense T1 weighed imaged, though they may look isointense in T2w IRM.
Please tell me what the correct answer is. I´m actually between a and b. :roll:
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Guillermo Ballarino
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| ayeshah_l
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I think its pit. adenoma
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| zaki
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sorry for the mistake in subject, man instead of woman
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Maverick
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| zaki
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Answer: D
Educational Objective: Recognize the causes of diabetes insipidus, and know how to treat them.
This case illustrates the importance of considering alternative causes in the patient presenting with polyuria and polydipsia. In the absence of an elevated serum calcium or glucose level or the administration of an osmotically active agent such as mannitol, the presence of hypernatremic polyuria and polydipsia is consistent with diabetes insipidus. The concomitant presence of other features relating to loss of hypothala-mic/pituitary function suggests that the disease is related to loss of antidiuretic hormone (ADH) (central diabetes insipidus) rather than resistance to its action (nephrogenic diabetes insipidus). The response to administration of DDAVP (desmopressin) further supports this.
Lymphocytic hypophysitis presents most often in women during the peripartum period. However, there have been several reports of this disease in men as well as postmenopausal women. The autoimmune destruction associated with this disease is extremely variable, with some patients experiencing loss of both anterior and posterior function (such as this patient) and others exhibiting loss of only a selected anterior pituitary hormone (such as adrenocorticotropic hormone [ACTH] alone); many have hyperprolactinemia. Similarly, the course of recovery is variable. In some patients, the destruction is associated with an expanding mass that results in compression of adjacent structures and may therefore require surgical decompression. In others, if the disease is highly suspected and other causes unlikely, conservative management with hormone replacement (if necessary) is sufficient. Serial imaging has documented regression of the “tumor mass” with time. Glucocorticoids have not been shown to be of clear value unless a deficiency is noted. Because there is no specific test that confirms the diagnosis other than histologic examination, the diagnosis must be suspected to avoid unnecessary exploratory surgery. In addition to women in the peripartum period, lymphocytic hypophysitis should also be suspected in patients who present with a pituitary mass that is associated with loss of both anterior and posterior pituitary hormones, those in whom medical therapy is ineffective in lowering elevated prolactin levels, and those who present with a rapidly expanding pituitary mass.
Expanding pituitary adenomas almost never grow to affect ADH synthesis and therefore do not present with diabetes insipidus. Although metastatic disease to the pituitary gland can present with central diabetes insipidus, it is a rare occurrence, especially in a patient of this age. Moreover, the patient has no clinical or biochemical features to suggest systemic sarcoidosis or a neurologic component to this typically infiltrative disease
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Maverick
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hey.... this woman is neither pregnant, post partum, man nor post menopausal. She does not have elevated prolactin, either.
You have a point why not to choose the otherones, though.
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| wkyaw2003
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i agree with you zaki. i'm from UK and have already finished my mrcp part -1. i'm currently studying for usmle step-2 and i really appreciate your effort in this forum. i would be gratefu.l if you can give me some advice regarding usmle step-2. my e-mail address is kgyi2003@yahoo.co.uk
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| ayeshah_l
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This is a good case and i admit a bit tricky. One really needs to know the finer points of both pit.adenoma (PA) and Lymphocytic hypophysitis (LH) to be able to answer this Q. I found a few pointers which in this case will help us understand better y this isn't PA
'Pituitary adenomas typically have a contrast enhancing or hypointense area confined to or compressing adjacent normal gland. The picture of LH is quite different; The gland is diffusely and dramatically enhancing Also, the presence of a thickened and contrast enhancing infundibular stalk is nearly pathognomonic"
It must be stressed that a high index of suspicion is necessary to diagnose lymphocytic hypophysitis when only the protean signs of mild headache and malaise are present
There are other features of LH like hyperprolectinemia etc, but these , i thought, are most relevant as far as diagnosing this case is concerned.
Hope it helps 
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