Clinical Investigation Unit Testing Endocrinology Rounds July 28, 2010 Selina Liu PGY5 Endocrinology

Outline  Background - Dynamic Endocrine Testing  Clinical Investigation Unit - Available Tests  Examples  Growth Hormone Deficiency  Adrenal Insufficiency  Other

Background  What can we measure?  basal hormone levels  stimulated or suppressed hormone levels  Why do we do dynamic endocrine testing?  test of secretory reserve

Background  INSUFFICIENCY/DEFICIENCY  OVERPRODUCTION Stimulate! Suppress!

Available Tests  Which glands/axes can we stimulate or suppress?  Pituitary  Other

Pituitary Hormones

Pituitary Hormone Disorders Hormone Underproduction Overproduction GH LH/FSH TSH ACTH Prolactin GH DeficiencyAcromegaly Hypogonadotropic Hypogonadism Central Hypothyroidism Central Adrenal InsufficiencyCushing’s Hyperprolactinemia Central Hyperthyroidism ADH Diabetes Insipidus

Central Hyperthyroidism Pituitary Hormone Disorders Hormone Underproduction Overproduction GH LH/FSH TSH ACTH Prolactin GH DeficiencyAcromegaly Hypogonadotropic Hypogonadism Central Hypothyroidism Central Adrenal InsufficiencyCushing’s Hyperprolactinemia ADH Diabetes Insipidus  /normal TSH,  fT3, fT4  /normal ACTH,  cortisol  GH  IGF-1  /normal LH, FSH,  estradiol, testosterone

Available CIU Tests GH Deficiency Hypogonadotropic Hypogonadism Central Hypothyroidism Adrenal Insufficiency Insulin Tolerance Test GnRH Stimulation Test TRH Stimulation Test ACTH Stimulation Test CRH Stimulation Test Insulin Tolerance Test Diabetes Insipidus Water Deprivation Test Acromegaly Glucose Tolerance Test Triple Bolus Test

Examples  Growth Hormone Deficiency

Growth Hormone Secretion GHRH = GH releasing hormone SRIF = somatotropin release inhibiting factor (aka somatostatin) IGFBP = IGF binding protein Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

Growth Hormone Secretion  pulsatile secretion  healthy adult ~10 pulses/day  longest ~1h after sleep onset  if suspect GH deficiency, random GH level not useful Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

GH Deficiency - Causes

GH Deficiency – Clinical Presentation  CV Risk factors  abnormal lipid profile, atherosclerosis, insulin resistance  Body composition  increased body fat mass with altered distribution, increased waist:hip, decreased lean body mass  Exercise capacity  reduced muscle mass, impaired max oxygen uptake  QOL  decreased energy, poor concentration, low self-esteem

GH Deficiency - Diagnosis  screening test - IGF-1 level ?  IGF-1 – affected by age, obesity, nutrition, comorbidities etc.  Marzullo P et al Usefulness of Different Biochemical Markers of the Insulin-Like Growth Factor (IGF) Family in Diagnosing Growth Hormone Excess and Deficiency in Adults J Clin Endocrinol Metab 26:

 58 healthy, 83 acromegalic, 34 GH deficient subjects  GH deficient: 34 hypopituitarism  prev pituitary tumour/craniopharyngioma/meningioma resection, except for 2 with idiopathic GH deficiency  diagnosed based on arginine-GHRH stimulation test  19 female, 15 male  ages J Clin Endocrinol Metab 26:

 GH deficient subjects had significantly lower mean IGF-1 levels vs healthy control subjects Marzullo P et al J Clin Endocrinol Metab 26:

Sensitivity: IGF-1 41% Marzullo P et al J Clin Endocrinol Metab 26: therefore – not a good screening test!

2006. J Clin Endocrinol Metab 91:

Growth Hormone Deficiency Endocrine Society Clinical Practice Guidelines (2006) Recommendation: “Do it” or “Don’t do it” – indicating a judgement that most well-informed people would make Suggestion: “Probably do it” or “Probably don’t do it” – indicating a judgement that a majority of well-informed people would make but a substantial minority would not

Growth Hormone Deficiency Endocrine Society Clinical Practice Guidelines (2006) Suggestion: IGF-1  if normal – does not exclude GH deficiency  if in context of pituitary disease, provocative testing is mandatory (level of evidence – high)  if low, and no catabolic disorders, liver disease, indicates severe GH deficiency  may be useful in identifying patients who will benefit from treatment (level of evidence – moderate)

Growth Hormone Deficiency  Dynamic tests:  insulin tolerance test (ITT) – GOLD STANDARD  others arginine-GHRH arginine alone clonidine arginine + l-dopa (arginine – decreases SRIF from hypothalamus)

Growth Hormone Secretion GHRH = GH releasing hormone SRIF = somatotropin release inhibiting factor (aka somatostatin) IGFBP = IGF binding protein Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier. arginine -

Insulin Tolerance Test  first described in 1941

Insulin Tolerance Test  To diagnose GH deficiency  also to diagnose adrenal insufficiency, panhypopituitarism  Contraindications:  seizure disorder, cerebrovascular disease, coronary artery disease  can precipitate adrenal crisis  check baseline 08:00 am cortisol – do not do if <100 nmol/L  need close monitoring, physician supervision

Growth Hormone Deficiency  Insulin Tolerance Test (ITT)  symptomatic hypoglycemia and fall in BG < 2.2 mmol/L  will increase GH to a maximal level >10  g/L increment of 6  g/L = normal  plasma cortisol should peak at least nmol/L Gardner DG & Shoback D (eds) 2007 Greenspan’s Basic & Clinical Endocrinology, Eighth Edition

Normal ITT (5.6 mmol/L) (4.4 mmol/L) (3.3) (2.2) (1.1 mmol/L)  g/L (275.9 nmol/L) (827.7 nmol/L)

TestGH Value < μ g/LReferences Insulin Tolerance Test5.1Biller et al Arginine + GHRH4.1Biller et al Arginine + l-Dopa1.7Biller et al Hexarelin + GHRH3.0Gasperi et al GHRH + GHRP-615.0Popovic et al Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier. Recommended Test Sensitivity (95% CI) to diagnose adult GH deficiency

2002. J Clin Endocrinol Metab 87:  39 subjects - multiple pituitary hormone deficiency (MPHD)  13 female, 26 male, aged  adult onset hypothalamic-pituitary disease  34 matched controls (age, sex, BMI, estrogen status)  14 female, 20 male, age 24-68

Biller BMK et al J Clin Endocrinol Metab 87:

100% sens 100% spec AUC 1.0  MPHD subjects vs. matched controls Biller BMK et al J Clin Endocrinol Metab 87:

To minimize misclassification:  ITT – peak serum GH 5.1  g/L (96% sens, 92% spec)  Arg-GHRH – peak serum GH 4.1  g/L (95% sens, 91% spec)

Biller BMK et al.  the ITT and the arginine-GHRH provided the greatest accuracy in discriminating between patients with MPHD and their matched controls  arginine- GHRH test – better preferred by patients  arginine-GHRH test – good alternative to ITT  arginine-L-dopa – reasonable 3 rd option  basal IGF-1 < 77  g/L was 95% specific for GH deficiency Biller BMK et al J Clin Endocrinol Metab 87:

2006. J Clin Endocrinol Metab 91:

Growth Hormone Deficiency Endocrine Society Clinical Practice Guidelines (2006) Recommendations:  adults with structural hypothalamic/pituitary disease, surgery or irradiation to these areas, or other pituitary hormone deficiencies should be considered for evaluation for acquired GH deficiency (level of evidence – high)

Growth Hormone Deficiency Endocrine Society Clinical Practice Guidelines (2006) Recommendations:  The ITT or arginine-GHRH test is the preferred test for establishing the diagnosis of GH deficiency  but – in those with clearly established recent hypothalamic causes of GH deficiency, i.e. irradiation, arginine-GHRH test may be misleading (level of evidence – high)  GHRH directly stimulates pituitary

Growth Hormone Deficiency Endocrine Society Clinical Practice Guidelines (2006) Suggestions:  the presence of deficiencies in > 3 pituitary axes strongly suggests GH deficiency, and in this context, provocative testing is optional (level of evidence – moderate)

2007. Eur J Endocrinol 157:

Growth Hormone Deficiency Growth Hormone Research Society Consensus Statement (2007)  ITT, arginine-GHRH, GHRH-GHRP, glucagon tests all well-validated in adults  glucagon useful if ITT contraindicated, if GHRH or GHRP not available  IGF-1 good screening test  normal IGF-1 does not exclude GH deficiency

Examples  Adrenal Insufficiency  Primary  low cortisol, high ACTH  Secondary/Tertiary (Central)  low cortisol, low or normal ACTH

ACTH and Cortisol Secretion Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

ACTH and Cortisol Secretion Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.  pulsatile secretion  circadian rhythm  highest in a.m. 24:0012:0008:0020:00

Adrenal Insufficiency - Causes  Primary – adrenal  Secondary – pituitary  Tertiary – hypothalamus

Primary Adrenal Insufficiency - Causes

Secondary Adrenal Insufficiency - Causes  Panhypopituitarism  Isolated ACTH Deficiency - ?autoimmune  Familial Cortisol-Binding Globulin Deficiency  Megestrol acetate  Opiates  Traumatic brain injury

Tertiary Adrenal Insufficiency - Causes  Chronic high dose glucocortioid therapy  Post-cure Cushing’s syndrome  Other  tumours  cranial irradiation  infiltrative diseases i.e. sarcoidosis

Adrenal Insufficiency – Clinical Presentation

Adrenal Insufficiency – Clinical Presentation

Adrenal Insufficiency – Clinical Presentation Central Adrenal Insufficiency (Secondary or Tertiary)  differ from primary:  no hyperpigmentation (ACTH not increased)  no hyperkalemia  dehydration, hypotension less severe  hypoglycemia may occur  GI symptoms less common  local symptoms (headache etc.), other signs of hypopituitarism

Adrenal Insufficiency – Diagnosis Steps: 1. To rule out adrenal insufficiency - fasting 08:00 am cortisol  if 08:00 am cortisol >524 nmol/L, adrenal insufficiency excluded  if 08:00 am cortisol <83 nmol/L, adrenal insufficiency confirmed  if 08:00 am cortisol between these values, is borderline – need further testing reviewed in Oelkers W. N Engl J Med 1996; 335(16):

Adrenal Insufficiency – Diagnosis Steps: 2.If suspect primary adrenal insufficiency, do both 08:00 am cortisol and ACTH  low cortisol and high ACTH - primary  if cortisol normal – rules out primary, but does not exclude mild secondary adrenal insufficiency  in primary adrenal insufficiency – ACTH usually >22pmol/L  low cortisol and low/normal ACTH – secondary/tertiary reviewed in Oelkers W. N Engl J Med 1996; 335(16):

Oelkers W. N Engl J Med 1996; 335(16): (660 pmol/L ) (0.7 pmol/L ) (6.6 pmol/L) (1380 nmol/L) (8 nmol/L) (83 nmol/L)(276 nmol/L)

Adrenal Insufficiency – Diagnosis Dynamic Tests:  to confirm adrenal insufficiency:  high dose short ACTH stimulation test  250  g cosyntropin (Cortrosyn) IV  cortisol/ACTH at -15, 0, 30, 60 min  if peak cortisol >500 nmol/L (preferably >550 nmol/L), rules out primary adrenal insufficiency Oelkers W. N Engl J Med 1996; 335(16):

Adrenal Insufficiency – Diagnosis ** if suspect recent/mild secondary – can have normal high dose ACTH stimulation test  because of high dose (only need 5  g to maximally stimulate adrenals), and if recent – adrenals will not have atrophied yet  low dose short ACTH stimulation test  1  g cosyntropin (Cortrosyn) IV  cortisol/ACTH at -15, 0, 30, 60 min  normal peak cortisol >500 nmol/L Oelkers W. N Engl J Med 1996; 335(16):

Adrenal Insufficiency – Diagnosis  if abnormal low dose ACTH stimulation test, require further testing  insulin tolerance test  will confirm if secondary/tertiary adrenal insufficiency Oelkers W. N Engl J Med 1996; 335(16):

Adrenal Insufficiency – Diagnosis  to distinguish secondary vs. tertiary adrenal insufficiency: CRH stimulation test (if you can get CRH!)  100  g CRH IV  ACTH, cortisol at -15, 0, 30, 60, 90 min  low ACTH = pituitary adrenal insufficiency (secondary)  high ACTH = hypothalamic adrenal insufficiency (tertiary) (values not as well standardized as for ITT) Oelkers W. N Engl J Med 1996; 335(16):

Other Pituitary Testing  Acromegaly – Glucose Tolerance Test  Hypogonadism - GnRH Stimulation Test  Central Hypothyroidism – TRH Stimulation Test  Panhypopituitarism - Triple/Double Bolus Test  Diabetes Insipidus – Water Deprivation Test

Glucose Tolerance Test  to confirm diagnosis of acromegaly Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

45y M – 2 months post-pituitary macroadenoma resection  inadequate suppression of GH  persistent acromegaly

GnRH Stimulation Test  to confirm diagnosis of hypogonadotropic hypogonadism Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

TRH Stimulation Test  to confirm diagnosis of central hypothyroidism (and hypoprolactinemia) Kronenberg HM et al. Williams Textbook of Endocrinology. 11th edition Saunders Elsevier.

Triple Bolus Test  Components:  Insulin Tolerance Test  GH deficiency, adrenal insufficiency  GnRH stimulation test  hypogonadotropic hypogonadism  TRH stimulation test  central hypothyroidism, hypoprolactinemia  if suspect panhypopituitarism

1984. J Neurosurg 61(3):

32 y F – 3 yrs post Rathke’s cleft resection

Water Deprivation Test  to confirm diagnosis of central diabetes insipidus

Non-Pituitary Dynamic Tests  Medullary Thyroid Cancer – Calcium stimulation test,  Primary Hyperaldosteronism – Saline suppression test

Clinical Investigation Unit - CIU  Liz Froats, RN  Room B

References  Marzullo P et al J Clin Endocrinol Metab 26:  Molitch ME et al J Clin Endocrinol Metab 91:  Biller BMK et al J Clin Endocrinol Metab 87:  Oelkers W. N Engl J Med 1996; 335(16):  Bernstein M et al J Neurosurg 61(3):  Kronenberg HM et al. Williams Textbook of Endocrinology. 11 th edition Saunders Elsevier.  Gardner DG & Shoback D (eds) Greenspan’s Basic & Clinical Endocrinology, Eighth Edition McGraw-Hill.      