A. Bennet

Insulin, C-peptide and proinsulin for the biochemical diagnosis of hypoglycaemia related to endogenous hyperinsulinism

OBJECTIVE We evaluated the respective value of insulin, C-peptide and proinsulin levels in 33 patients with endogenous hyperinsulinism and in 67 controls to determine the best parameters and thresholds to make or to rule out the diagnosis of endogenous hyperinsulinism. RESULTS When blood glucose levels were below 2.5 mmol/l, insulin was <21 pmol/l in 8-35% of the patients and in all controls; C-peptide was >0.2 nmol/l in all insulinomas but not in the nesidioblastosis or in the controls; proinsulin was >5 pmol/l in all patients but not in the controls. When fasting blood glucose levels reached 2.5-3.3 mmol/l, proinsulin was <22 pmol/l in all the controls and >22 pmol/l in 74% of the patients. Proinsulin after an overnight fast was below 22 pmol/l in all non-obese controls and above 22 pmol/l in 73% of non-obese patients. CONCLUSION Proinsulin levels above 5 pmol/l with blood glucose levels below 2.5 mmol/l during a 72 h fast test represent the best criterion for the diagnosis of endogenous hyperinsulinism, reaching 100% diagnostic specificity and sensitivity. Concomitant C-peptide levels above 0.2 nmol/l also make the diagnosis of all our insulinoma patients, not the diagnosis of nesidioblastosis, while insulin levels have much less diagnostic accuracy. Whether proinsulin levels above 22 pmol/l could also make the diagnosis of endogenous hyperinsulinism in part of the patients at the time of fasting blood glucose levels between 2.5 and 3.3 mmol/l or after an overnight fast in non-obese subjects needs further study.

Short‐ and long‐term somatostatin analogue treatment in patients with hypoglycaemia related to endogenous hyperinsulinism

Background  The long‐term efficacy of somatostatin analogues on insulinomas has not been studied.

Gluten-induced enteropathy (coeliac disease) revealed by resistance to treatment with levothyroxine and alfacalcidol in a sixty-eight-year-old patient: a case report.

We report the case of a female patient in whom gluten-induced enteropathy was revealed at the age of 68 years by resistance to treatment with levothyroxine and alfacalcidol. This case report shows that malabsorption without major digestive symptoms led to reduction of absorption of levothyroxine (LT(4)) and alfacalcidol, although the patient had normal free thyroxine (T(4)) levels (which increased by 45.8% after a loading dose of 250 microg of levothyroxine), high thyrotropin (TSH) and slightly elevated 1.25 dihydroxy-vitamin D(3) levels, low free triiodothyronine (T(3)) and calcium levels were found. Malabsorption had additional effects by reducing T(3) and calcium levels. Because minor forms of gluten-induced enteropathy are not rare in patients with thyroid autoimmune diseases, the cost-effectiveness of using antigliadin antibodies as a first-line test (instead of an LT(4) loading test) in patients requiring daily doses of levothyroxine above 2 microg per kg of body weight, whatever their age may be, is discussed.

Normal pregnancy in a woman with nesidioblastosis treated with somatostatin analog octreotide.

Objective: We report the case of a 36-yr-old woman with nesidioblastosis treated throughout pregnancy with high doses of octreotide. We studied the course of blood glucose, foetal growth and development. Methods: Blood samples were obtained every month throughout pregnancy and taken at birth from the umbilical cord. Sonography was performed repeatedly to monitor foetal growth. Results: The daily dose of octreotide was adapted to blood glucose levels: a dose of 1000 μg was infused during the first part of pregnancy, then it was decreased step by step during the last trimester of gestation. An elective cesarean section was performed at 32 weeks of gestation. High octreotide concentrations were obtained during the first part of gestation (range 2888–5021 pg/ml). During the third trimester of pregnancy blood glucose increased despite high insulin levels attesting physiological insulin-resistance. Plasma levels of placental GH and IGF-1 levels were similar to those observed in a normal pregnancy. Despite the presence of octreotide in the umbilical cord, TSH, free T4, PRL and pituitary GH concentrations were normal at birth. The female newborn (weight 3520 g, length 52 cm) had no malformation, and presented with normal postnatal development. Conclusion: Our study demonstrates that: 1) octreotide treatment can be effective in controlling endogenous hyperinsulinism during pregnancy; 2) octreotide does not affect physiological changes during pregnancy such as insulin-resistance or placental GH level; 3) exposure of the foetus to octreotide throughout pregnancy does not induce any malformation and does not affect foetal development.

Ectopic Cushing's syndrome due to a pheochromocytoma: a new case in the post-partum and review of literature.

Cushings syndrome due to AdrenoCorticoTropic Hormone (ACTH)-secreting pheochromocytoma has been rarely reported during pregnancy and post-partum. We report the case of a 30-year-old woman who presented 3 months after delivery acute psychiatric signs and rapid progressive features of Cushings syndrome. Hormonal tests confirmed ACTH-dependant Cushings syndrome. A computed tomography scan revealed a 25×30 mm tumoral mass in the left adrenal gland and octreoscan scintigraphy showed only an uptake of the radiolabelled octreotide by the adrenal tumor. Fractionated 24-h urinary catecholamines and metanephrines were in the normal range, except for slightly increased adrenalin levels. A left laparoscopic adrenalectomy was performed with acute pulmonary oedema following the anesthesia. Histological examination revealed a 3.5×2.5 cm adrenal tumor consistent with a pheochromocytoma without signs of malignancy. The tumor cells immunostained for ACTH and diffuse hyperplasia of adrenocortical cells was observed. After surgery and short stay in intensive care unit, clinical and biological signs rapidly improved and both anti-hypertensive treatment and insulin injections were withdrawn. Genetic testing did not reveal germline mutations in RET protooncogene, Von Hippel Lindau and succinate deshydrogenase genes.

Pituitary Apoplexy and Idiopathic Thrombocytopenic Purpura: A New Case and Review of the Literature

Pituitary apoplexy can occur as a complication of idiopathic thrombocytopenic purpura. We report here a new case of such association. A male patient aged 59 years, complaining of decreased libido for one year, was referred to the emergency department for purpura and severe thrombocytopenia (4000 platelets/mm3). 24 hours after the cutaneous rash the patient presented with clinical symptoms of bilateral cavernous sinus compression comprising ptosis, bilateral ophtalmoplegia and right supraorbital hypoesthesia. Cranial CT scan showed an enlarged sella and a pituitary mass with signs of intrapituitary haemorrhage. Hormonal evaluation showed hyperprolactinemia (50 ng/mL) and hypopituitarism, and the patient needed substitution with hydrocortisone and levothyroxine. Immunoglobulins and corticosteroids were given to the patient to treat thrombocytopenia, then worsening of neurological and ophtalmological symptoms led to pituitary surgery. Histopathological examination found necrotical pituitary tissue. Immunostaining with an anti-prolactin antibody was positive in several groups of cells. Neurological symptoms subsided and thrombocytopenia was corrected by treatment. In conclusion, we report a case of pituitary apoplexy due to severe thrombocytopenia occurring as a complication of a preexisting macroprolactinoma.

Plasma fibrinolytic activity in a group of hypogonadic men

Fibrinolytic activity in response to venous occlusion (fibrin plate assay and tissue plasmogen activator antigen) was measured in 19 hypogonadic men (group 1), 23 non-hypogonadic men with deep venous thrombosis (DVT) antecedents and 20 healthy men (control group). Four hypogonadic men had DVT antecedents. Two of 20 controls were low responders against 6/19 and 6/23 in groups 1 and 2, respectively, (non-significant difference). The four hypogonadic men with DVT antecedent had abnormal response to venous occlusion. Whether defective fibrinolysis is causally related to hypogonadism cannot be established from these results but this study indicates that the combination of defective fibrinolysis, hypogonadism and DVT in man is relatively common.

Increased plasma β-hydroxybutyrate levels during the fasting test in patients with endogenous hyperinsulinaemic hypoglycaemia

OBJECTIVE The objective of the present study was to determine whether a plasma β-hydroxybutyrate (BOHB) level >2700 μmol/l during the 72-h fasting test is sufficient to rule out the diagnosis of endogenous hyperinsulinaemic hypoglycaemia (EHH). RESEARCH DESIGN AND METHODS We retrospectively studied BOHB levels in 39 patients with EHH who had undergone a 72-H fasting test to make the diagnosis of EHH, and we compared EHH patients with BOHB levels 2700 MOL/L (group 1), EHH PATIENTS with BOHB levels 2700 MOL/L (group 2) and 59 controls (median glycaemia: 3.2  mmol/l and median BOHB: 6095 μmol/l). RESULTS During a 72-h fasting test, nine patients (group 1) had BOHB levels >2700  μmol/l (median 6140 and range 2957-7824) and 30 patients (group 2) had BOHB levels <2700 μmol/l (median 542 and range 0-2607). In group 1, four patients had undergone partial pancreatectomy previously and were evaluated for the recurrence of hypoglycaemia, whereas none of the group 2 patients had been operated. The duration of the fasting test was longer in group 1 than in group 2 (P<0.0001), and at the end of the fasting test, plasma glucose concentrations were not significantly different (P=0.0617), but insulin (P=0.004), C-peptide (P=0.0015) and proinsulin (P=0.0038) levels were significantly lower in group 1 patients than in group 2 patients, suggesting lower insulin secretion and/or impaired glycaemic counter-regulation. CONCLUSION During a fasting test, a BOHB level >2700 μmol/l is observed in some EHH patients, suggesting that BOHB levels cannot rule out the recurrence of EHH, in particular, after partial pancreatectomy.

Virilising ovarian tumour: a case associating a Sertoli-Leydig cell tumour and a Brenner tumour

Ovarian Sertoli-Leydig cell tumours (SLCT), also termed arrhenoblastomas, are the most frequent virilising tumours in women of reproductive age. Very rare secretory Brenner tumours (BT) have been described, generally after the menopause. A 31-year-old woman sought medical advice for secondary amenorrhoea, progressive hirsutism and a 5-year history of virilisation syndrome with clitoromegaly. Testosterone was markedly high (285 ng/dl, N<85) with moderate elevation of delta 4-androstenedione (D4AD) (311 ng/dl, N <270), dehydroepiandrosterone sulfate (DHEAS) (366 μg/dl, N <340) and 17-hydroxyprogesterone (17OHP) (275 ng/dl). LH was 9 IU/l, FSH 4.3 IU/l, estradiol 60 pg/ml and progesterone 314 ng/100 ml. Cortisol was decreased (1.3 μg/dl) after the dexamethasone suppression test. Pelvic MRI showed a 5-cm right ovarian tumour with a 2.5 cm nodular component and cystic areas, and two nodules measuring 11 mm and 15 mm above the right and left ovaries. After right ovariectomy by laparoscopy, pathological examination concluded on a 3-cm SLCT and a 2-cm BT; the nodules above the ovaries were dysembryoplastic cysts. Postoperatively, testosterone level was normal after 24 h (26 ng/dl), estradiol and progesterone rapidly decreased, cyclic secretion then resumed and the patient menstruated at day 27. To our knowledge, this is the first report of an ovarian tumour associating a Sertoli-Leydig cell tumour and a Brenner tumour in a patient with virilisation syndrome which resolved after ovariectomy.

Impact of growth hormone hypersecretion on the adult human kidney

Acromegaly is most often secondary to a GH-secreting pituitary adenoma with increased Insulin-like Growth Factor type 1 (IGF-1) level. The consequences of GH/IGF-1 hypersecretion reflect the diversity of action of these hormones. The genes of the GH receptor (GHR), IGF-1, IGF-1 receptor (IGF-1R) and IGF-binding proteins (IGF-BP) are physiologically expressed in the adult kidney, suggesting a potential role of the somatotropic axis on renal structure and functions. The expression of these proteins is highly organized and differs according to the anatomical and functional segments of the nephron suggesting different roles of GH and IGF-1 in these segments. In animals, chronic exposure to high doses of GH induces glomerulosclerosis and increases albuminuria. Studies in patients with GH hypersecretion have identified numerous targets of GH/IGF-1 axis on the kidney: 1) an impact on renal filtration with increased glomerular filtration rate (GFR), 2) a structural impact with an increase in kidney weight and glomerular hypertrophy, and 3) a tubular impact leading to hyperphosphatemia, hypercalciuria and antinatriuretic effects. Despite the increased glomerular filtration rate observed in patients with GH hypersecretion, GH is an inefficient treatment for chronic renal failure. GH and IGF-1 seem to be involved in the physiopathology of diabetic nephropathy; this finding offers the possibility of targeting the GH/IGF-1 axis for the prevention and the treatment of diabetic nephropathy.