This document presents several clinical case studies in endocrinology: - A 48-year-old man with acromegaly, evidenced by a lack of suppression of growth hormone during an oral glucose tolerance test. - A 17-year-old woman with panhypopituitarism due to a craniopharyngioma, shown by low levels of various hormones including gonadotropins and cortisol. - A 31-year-old woman diagnosed with Cushing's syndrome based on an increased urine cortisol level and failure to suppress cortisol with dexamethasone. Further testing is needed to determine the underlying cause. - A 20-year-old woman

1. CLINICAL CASES IN
ENDOCRINOLOGY
Ahmed Jabbar Abbas

2. • The results were as follows:
Plasma
0 minutes: GH 24.5 mg/L
30 minutes: GH 24.6 mg/L
60 minutes: GH 23.7 mg/L
90 minutes: GH 20.5 mg/L
120 minutes: GH 25.8 mg/L
A 48-year-old man noticed that his hat size had increased, and his wife thought
that his appearance had changed since their marriage, his features becoming
coarser and his hands larger. Plasma insulin-like growth factor 1 (IGF-1)
concentration was raised and an oral glucose suppression test was performed.

3. • The plasma growth hormone (GH) concentration was not
suppressed during the test in any of the samples. These findings
are indicative of acromegaly; the clinical features are typical of
acromegaly. This case illustrates the principle of using a
suppression test when considering a condition involving a
hormone excess. In healthy individuals, plasma GH concentration
would be suppressed to less than 1 mg/L by the glucose intake.

4. A 17-year-old woman presented to the endocrine clinic because of
headaches, weakness and amenorrhea. The following baseline biochemical
endocrinetestresultswereobtained.
Luteinizinghormone 0.46mU/L (1–25)
Follicle-stimulatinghormone 0.87mU/L (1–15)
09.00hcortisol 56nmol/L (180–720)
Prolactin 460mU/L (<470)
TSH 0.21mU/L (0.20–5.0)
Freethyroxine(T4) 10.4pmol/L(12–25)
Oestradiol 60pmol/L (70–880)

5. The patient has panhypopituitarism. Note the low concentrations of plasma
gonadotrophins and secondary hypogonadism. A low plasma cortisol
concentration at 09.00 h implies also low adrenocorticotrophic hormone
(ACTH) concentration. The panhypopituitarism was subsequently found to
be due to a craniopharyngioma that had infiltrated the pituitary gland. Note
thatthiscaseillustratesanotherimportantprincipleofendocrinetesting:that
theplasma freeT4concentration islowbut theTSHconcentration iswithin
thereferencerange,whichisabnormalgiventhehypothyroxinaemia.

6. A31-year-oldwomanpresentedwitha3-monthhistoryofweightgain,
hirsutism,amenorrhoeaandhypertension.Herurinecortisol:creatinine
ratiowasincreased,andserumcortisoldiurnalrhythmwasabsent.
Treatmentwith0.5mgofdexamethasonedidnotsuppresshercortisol,and
insulin-inducedhypoglycaemiadidnotcauseherserumcortisoltorise.

7. • Cushing’ssyndromeisthemostlikelydiagnosisinthiscase.Onecanbe
confidentofthediagnosisinviewoftheincreasedurinary
cortisol:creatinineratio,andthefailuretosuppresswithlow-dose
dexamethasone.
EstablishingadiagnosisofCushing’ssyndromeisinsufficientasitis
essentialtodiscovertheunderlyingcausetoenablethecorrecttreatment
tobegiven.
Thispatientshouldhaveahigh-dosedexamethasonesuppressiontestwith
measurementofserumcortisolandACTH.Suppressionofthecortisol
wouldpointtothepituitary-dependentCushing’ssyndromeaswouldan
abnormallyincreasedACTHconcentration.
IfherACTHisabnormallyincreasedshemayundergoselectivevenous
catheterizationtolocatethesource,whichmaybeduetoacarcinoid
tumourofthelung.

8. •
Serum Result Reference range
Cortisol 450 160–565 nmol/L
FT4 30 9–21 pmol/L
FT3 9.5 2.6–6.2 pmol/L
TSH 6.0 0.2–4.5 mU/L
LH 1.1 1.5–9.0 U/L
FSH 1.4 1.5–9.0 U/L
Prolactin 850 <500 mU/L
GH <0.5
There was no change in serum TSH 20 and 60 min
after the injection of TRH (a TRH test).
A 20-year-old woman presented to her GP 9 months postpartum with
persistent galactorrhoea despite never having breastfed. She also
complained of agitation palpitations and weight loss. The following results
were found in a random sample and conf rmedin a second specimen
taken 7 days later:

9. • The results are consistent with hyperthyroidism caused by a
TSH secreting pituitary tumour (TSHoma) and hyper-
prolactinaemia due to hypothalamic disconnection causing loss
of inhibitory dopamine reaching the pituitary. In end-organ
resistance, the TSH response to TRH is normal or exaggerated
while a flat or blunted response is seen in TSHoma..
• TSHoma is rare with an incidence of 2 per 107, with most
patients presenting with thyrotoxicosis and hyper-
prolactinaemia.
•

10. A35-year-oldsecretaryattendedforfollow-upreviewofhertreatmentfor
Graves’disease.Carbimazoleadministration(15mgthreetimes/day)had
beenstarted1monthbefore.Theresultsforthyroidfunctiontestswereas
follows
•
TSH <0.01 0.2–4.5 mU/L
FT4 <5 9–21 pmol/L
FT3 2.5 2.6–6.2 pmol/L
Commentontheacceptabilityoftheseresults.Iftheyarenotacceptable,
whatwouldyoudo?

11. Plasma TSH measurements are not a reliable indicator of thyroid
status in the early months of treating hyperthyroid patients, as the
responsiveness of the thyrotrophs lags behind the fall in plasma
[FT4] and [FT3] for several weeks.
During these early months, plasma free thyroid hormone
measurements provide the most reliable indication of thyroid status.
In this patient, the results for plasma [FT4] and [FT3] clearly
indicated the need to reduce the dosage of carbimazole
immediately.

12. A 28-year-old woman attended the gynaecology out patient clinic because
of infertility. Her periods were noted to be irregular. She was on no
medication, and her renal function, liver function and blood glucose
concentrationwerenormal.Herplasmaresultswereasfollows
Thyroid-stimulatinghormone2.1mU/L(0.20–5.0)
Freethyroxine14.3pmol/L(12–25)
Prolactin414mU/L(<470)
Luteinizinghormone7.2U/L(1–25)
Follicle-stimulatinghormone5.4U/L(1–15)
Testosterone1.7nmol/L(1–3)
Sex-hormone-bindingglobulin33nmol/L(20–90)
Oestradiol564pmol/L(70–880)
21-dayplasmaprogesterone6.6nmol/L(>30)suggestsovulation

13. The low 21-day plasma progesterone concentration suggests a poor
luteal phase and possible anovulation. The patient was having
anovulatory menstrual cycles, which explained her infertility.

14. Thank you