SEMINAR
`
`Seminar
`
`Adrenal insufficiency
`
`Wiebke Arlt, Bruno Allolio
`
`Adrenal insufficiency is caused by either primary adrenal failure (mostly due to autoimmune adrenalitis) or by
`hypothalamic-pituitary impairment of the corticotropic axis (predominantly due to pituitary disease). It is a rare disease,
`but is life threatening when overlooked. Main presenting symptoms such as fatigue, anorexia, and weight loss are non-
`specific, thus diagnosis is often delayed. The diagnostic work-up is well established but some pitfalls remain,
`particularly in the identification of secondary adrenal insufficiency. Despite optimised life-saving glucocorticoid-
`replacement and mineralocorticoid-replacement therapy, health-related quality of life in adrenal insufficiency is more
`severely impaired than previously thought. Dehydroepiandrosterone-replacement therapy has been introduced that could
`help to restore quality of life. Monitoring of glucocorticoid-replacement quality is hampered by lack of objective methods
`of assessment, and is therefore largely based on clinical grounds. Thus, long-term management of patients with adrenal
`insufficiency remains a challenge, requiring an experienced specialist. However, all doctors should know how to
`diagnose and manage suspected acute adrenal failure.
`
`In 1855, Thomas Addison described a clinical syndrome
`characterised by wasting and hyperpigmentation, and
`identified its cause as destruction of the adrenal gland.
`However, life-saving glucocorticoid-replacement therapy
`for the condition did not become available until 1949, when
`Kendall, Sarett, and Reichstein first synthesised cortisone.
`Furthermore, despite this breakthrough, 150 years on there
`are still many advances and challenges with respect to the
`management of individuals with adrenal insufficiency.
`
`Epidemiology
`There are two types of adrenal insufficiency, primary and
`secondary (figure 1). Chronic primary adrenal insufficiency
`has a prevalence of 93–140 per million and an incidence of
`4·7–6·2 per million in white populations.1–4 These recent
`numbers are higher than those reported during the 1960s
`and 1970s,5,6 despite a continuous decline in tuberculous
`adrenalitis in the developed world, suggesting an increasing
`incidence of autoimmune adrenalitis.3,4 The age at diagnosis
`peaks in the fourth decade of life, with women more
`frequently affected than men.1–4
`Secondary adrenal
`insufficiency has an estimated
`prevalence of 150–280 per million,3,7–10 and also affects
`women more frequently than men. Age at diagnosis peaks
`in the sixth decade of life.8,9 Therapeutic glucocorticoid
`administration is thought to be the most common cause
`of
`secondary adrenal
`insufficiency,
`since
`chronic
`administration exogenous glucocorticoids induces atrophy
`of pituitary corticotroph cells. However, iatrogenic adrenal
`insufficiency becomes potentially relevant only during or
`after glucocorticoid withdrawal. Because iatrogenic adrenal
`insufficiency is transient in most cases,11 we suspect its
`prevalence to be lower than that of endogenous adrenal
`insufficiency.
`
`Lancet 2003; 361: 1881–93
`
`Division of Medical Sciences, University of Birmingham,
`Birmingham, UK (W Arlt MD); and Department of Medicine,
`Endocrine and Diabetes Unit, University of Würzburg,
`Josef-Schneider Strasse 2, 97080, Würzburg, Germany
`(Prof B Allolio MD)
`Correspondence to: Prof Bruno Allolio
`(e-mail: allolio_b@klinik.uniwuerzburg.de)
`
`Cause
`Primary adrenal insufficiency (panel 1)12–38
`During the times of Thomas Addison, tuberculous
`adrenalitis was by far the most prevalent cause of adrenal
`insufficiency and, in the developing world, it remains a
`major factor.39 In active tuberculosis, the incidence of
`adrenal involvement is 5%.40 In developed countries,
`80–90% of patients with primary adrenal insufficiency
`have autoimmune adrenalitis, which can arise as isolated
`(40%; slight male preponderance) or as part of an
`autoimmune polyendocrine syndrome ([APS]; 60%;
`female preponderance).12,41 APS type 1, also termed
`autoimmune polyendocrinopathy-candidiasis-ectodermal
`dystrophy (APECED), arises in up to 15% of patients with
`autoimmune adrenalitis. It is characterised by adrenal
`insufficiency,
`hypoparathyroidism,
`and
`chronic
`mucocutaneous
`candidiasis with
`onset
`during
`childhood.12,42 APECED might also comprise
`the
`autoimmune disorders seen in APS type 2, and in
`addition, childhood alopecia (40% of APECD patients),
`chronic active hepatitis (20%), and malabsorption (15%).12
`APECED is caused by mutations in the autoimmune
`regulator (AIRE) gene13,14 and is inherited in an autosomal-
`recessive fashion. APS type 2 is the most frequently seen
`APS and comprises adrenal insufficiency and autoimmune
`thyroid disease. The clinical spectrum also includes
`primary gonadal failure, type 1 diabetes mellitus, and other
`autoimmune diseases such as vitiligo, chronic atrophic
`gastritis, or coeliac disease. APS type 2 occurs with
`autosomal-dominant
`inheritance with
`incomplete
`
`Search strategy
`
`We searched Medline and PubMed for reviews and original
`articles related to adrenal insufficiency and published between
`1966 and December, 2002. Keywords used included adrenal
`insufficiency and incidence, prevalence, cause, origin,
`diagnosis, function test, imaging, hydrocortisone,
`glucocorticoid, mineralocorticoid, dehydroepiandrosterone,
`management, treatment, therapy, replacement, surveillance,
`crisis, bone mineral density, quality of life, well-being,
`disablement, pregnancy, prognosis, morbidity, and mortality.
`Citations were chosen on the basis of relevance to the specific
`topics covered.
`
`1881
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`For personal use. Only reproduce with permission from The Lancet Publishing Group.
`
`MYLAN PHARMS. INC. EXHIBIT 1098 PAGE 1
`
`

`

`SEMINAR
`
`Physiological situation
`
`Primary adrenal insufficiency
`
`Hypothalamus
`
`Hypothalamus
`
`Pituitary
`
`CRH
`
`ACTH
`
`Pituitary
`
`CRH
`
`ACTH
`
`Adrenal
`
`Adrenal
`
`Cortisol
`
`Cortisol
`
`Secondary adrenal insufficiency
`
`Hypothalamus
`
`Hypothalamus
`
`Pituitary
`
`CRH
`
`ACTH
`
`CRH
`
`Pituitary
`
`ACTH
`
`Secondary adrenal insufficiency
`(panel 2)48–55
`The most frequent cause of secondary
`adrenal insufficiency is a tumour of the
`hypothalamic-pituitary region, usually
`associated with panhypopituitarism
`caused by tumour growth or treatment
`with surgery or
`irradiation. Auto-
`immune lymphocytic hypophysitis is
`less frequent, mostly affecting women
`during or shortly after pregnancy.
`Isolated adrenocorticotropic hormone
`(ACTH) deficiency could also be of
`autoimmune
`origin
`since
`some
`patients concurrently have other
`autoimmune
`disorders,
`most
`frequently
`thyroid disease.49 The
`differential diagnosis of postpartum
`autoimmune hypophysitis
`includes
`Sheehan’s syndrome, which results
`from pituitary apoplexy, mostly due to
`pronounced
`blood
`loss
`during
`delivery. Very rarely mutations of
`genes important for pituitary develop-
`ment or for synthesis and processing of
`the
`corticotropin precursor pro-
`opiomelanocortin cause
`secondary
`adrenal insufficiency (panel 2).
`
`Adrenal
`
`Adrenal
`
`Cortisol
`
`Cortisol
`
`Pituitary disease
`
`Primary and secondary adrenal insufficiency
`CRH=corticotropin-releasing hormone.
`
`Hypothalamic disease
`
`penetrance, and shows a strong association with HLA-
`DR312,43 and CTLA-4.44,45 The combination of adrenal
`insufficiency with other autoimmune disorders, but without
`thyroid disease, is classified as APS type 4, and APS type 3
`involves autoimmune thyroid disease but not adrenal
`insufficiency.
`X-linked adrenoleukodystrophy is caused by a mutation
`in the ABCD1 gene,46 which encodes a peroxisomal
`membrane protein
`(adrenoleukodystrophy protein),47
`leading to accumulation of very-long-chain fatty acids (>24
`carbon atoms). The clinical picture comprises adrenal
`insufficiency and neurological impairment due to white-
`matter demyelination. The two major forms are cerebral
`adrenoleukodystrophy (50% of cases; early childhood
`manifestation;
`rapid progression) and adrenomyelo-
`neuropathy (35% of cases; onset in early adulthood; slow
`progression) with restriction of demyelination to spinal cord
`and peripheral nerves.16 Adrenal insufficiency can precede
`the onset of neurological symptoms and is the sole
`manifestation of disease in 15% of cases.16
`Other causes of primary adrenal insufficiency—eg,
`adrenal infiltration or haemorrhage—are rare. Congenital
`or neonatal primary adrenal insufficiency accounts for only
`1% of all cases. However, the elucidation of the genetic
`basis of underlying diseases has emphasised the importance
`of
`specific genes
`for
`adrenal development
`and
`steroidogenesis (panel 1).
`
`Pathophysiology and clinical
`presentation (panel 3)
`Glucocorticoids are secreted from the
`adrenal zona fasciculata under the
`control of hypothalamic corticotropin-
`releasing hormone
`and pituitary
`corticotropin. Cortisol secretion
`is
`diurnal with maximum concentrations
`measured early in the morning and
`trough concentrations noted around
`midnight.56 Mineralocorticoids
`are
`produced by the zona glomerulosa,
`mainly under the control of the renin-
`angiotensin system. Thus, mineralocorticoid secretion is
`preserved
`in
`secondary
`adrenal
`insufficiency.
`Dehydroepiandrosterone secretion by the zona reticularis is
`also diurnal and is acutely increased by ACTH. However,
`although cortisol secretion varies little throughout life,
`dehydroepiandrosterone secretion is age dependent, with an
`increase noted at age 6–10 years (adrenarche), which
`continues until age 20–30 years. Thereafter, dehydroepian-
`drosterone concentrations steadily fall. This pattern suggests
`the existence of ACTH-independent factors, controlling
`release of dehydroepiandrosterone.57
`life-
`insufficiency—ie,
`Patients with acute adrenal
`threatening adrenal crisis—typically present with severe
`hypotension or hypovolaemic shock, acute abdominal
`pain, vomiting, and often fever. Such individuals are,
`therefore, sometimes misdiagnosed as having an acute
`abdomen. In a series of 91 patients with Addison’s
`disease,58 adrenal crisis led to the initial diagnosis of
`adrenal insufficiency in half of them. In children, acute
`adrenal insufficiency often presents as hypoglycaemic
`seizures. Deterioration of glycaemic control with recurrent
`hypoglycaemia can be the presenting sign of adrenal
`insufficiency in patients with pre-existing type 1 diabetes.
`In APS type 2, onset of autoimmune hyperthyroidism (or
`thyroxine
`replacement
`for newly diagnosed hypo-
`thyroidism) can precipitate adrenal crisis due to enhanced
`cortisol clearance.
`
`1882
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`For personal use. Only reproduce with permission from The Lancet Publishing Group.
`
`MYLAN PHARMS. INC. EXHIBIT 1098 PAGE 2
`
`

`

`Panel 1: Causes of primary adrenal insufficiency
`
`Diagnosis
`
`Clinical features in addition to
`adrenal insufficiency
`
`Autoimmune adrenalitis
`Isolated autoimmune adrenalitis No other features
`Auotimmune adrenalitis as part
`of APS12
`APS type 1 (APECED)
`
`APS type 2
`
`APS type 4
`
`Infectious adrenalitis
`Tuberculous adrenalitis
`AIDS
`Fungal adrenalitis
`
`Hypoparathyroidism, chronic mucocutaneous
`candidiasis, other autoimmune disorders
`Thyroid disease, type 1 diabetes mellitus
`other autoimmune diseases
`Other autoimmune diseases, excluding thyroid
`disease or diabetes
`
`Other organ manifestations of tuberculosis
`Other AIDS-associated diseases
`Mostly in immunosuppressed patients
`
`Genetic disorders leading to adrenal insufficiency
`Adrenoleukodystrophy,
`Demyelination of CNS (cerebral
`adrenomyeloneuropathy
`adrenoleukodystrophy), spinal cord, or
`peripheral nerves (adrenomyeloneuropathy)
`
`SEMINAR
`
`Pathogenesis or genetics
`
`Associations with HLA-DR3, CTLA-4
`
`AIRE gene mutations (21q22.3)13,14
`
`Associations with HLA-DR3, CTLA-4
`
`Associations with HLA-DR3, CTLA-4
`
`Tuberculosis
`HIV-1, cytomegalovirus15
`Cryptococcosis, histoplasmosis,
`coccidoidomycosis
`
`Mutation of the ABCD1 gene encoding for
`the peroxisomal adrenoleukodystrophy
`protein16
`
`Congenital adrenal hyperplasia
`21-hydroxylase deficiency
`11␤-hydroxylase deficiency
`3␤-HSD type 2 deficiency
`
`17␣-hydroxylase deficiency
`
`Congenital lipoid adrenal
`hypoplasia
`
`Smith-Lemli-Opitz syndrome
`
`Ambiguous genitalia in girls
`Ambiguous genitalia in girls and hypertension
`Ambiguous genitalia in boys, postnatal virilisation
`in girls
`Ambiguous genitalia in boys, lack of puberty in both CYP17 mutation
`sexes, hypertension
`XY sex reversal
`
`CYP21 mutation
`CYP11B1 mutation17
`HSD3B2 mutation18
`
`Mental retardation, craniofacial malformations,
`growth failure
`
`Mutations in the steroidogenic acute
`regulatory protein (SIAR) gene;19 mutations in
`CYP11A (encoding P450scc)20
`7-dehydrocholesterol reductase mutations in
`gene DHCR721,22
`
`Mutation in NROB123
`Deletion of the Duchenne muscular
`dystrophy, glycerol kinase, and NROB1 genes24
`Mutation in NR5A125
`Unknown26
`
`Mitochondrial DNA deletions27,28
`
`ACTH receptor (MC2R) mutations29
`Unknown30
`Mutations in triple A gene (AAAS)
`encoding for a WD-repeat protein31,32
`
`Septic shock, specifically meningococcal
`sepsis (Waterhouse-Friderichsen syndrome);
`primary antiphospholipid syndrome33
`Adrenal metastases34 primary adrenal
`lympoma sarcoidosis, amyloidosis,
`haemochromatosis
`Unresolved Cushing’s syndrome
`Treatment with mitotane,35
`aminoglutethimide, etomidate,36,37
`ketoconazole, suramin,38 mifepristone
`
`SF-1 linked
`IMAGe syndrome
`
`Kearns-Sayre syndrome
`
`Adrenal hypoplasia congenita
`Hypogonadotropic hypogonadism
`X-linked
`Xp21 contiguous gene syndrome Duchenne muscular dystrophy and glycerol kinase
`deficiency (psychomotor retardation)
`XY sex reversal
`Intrauterine growth retardation, metaphyseal
`dysplasia, adrenal, insufficiency, and genital
`anomalies (IMAGe)
`External ophthalmoplegia, retinal degeneration,
`and cardiac conduction defects; other
`endocrinopathies
`Glucocorticoid deficiency, but no impairment
`of mineralocorticoid synthesis
`
`ACTH insensitivity syndromes
`(familial glucocorticoid
`deficiency)
`Type 1
`Type 2
`Triple A syndrome
`(Allgrove’s syndrome)
`
`Bilateral adrenal haemorrhage
`
`Tall stature
`No other features
`Alacrimia, achalasia; additional symptoms—eg,
`neurological impairment, deafness,
`mental retardation, hyperkeratosis
`Symptoms of underlying disease
`
`Adrenal infiltration
`
`Symptoms of underlying disease
`
`Bilateral adrenalectomy
`Drug-induced adrenal
`insufficiency
`
`Symptoms of underlying disease
`No other symptoms
`
`HSD=hydroxy-⌬-5-steroid dehydrogenase.
`
`1883
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`
`MYLAN PHARMS. INC. EXHIBIT 1098 PAGE 3
`
`

`

`SEMINAR
`
`Panel 2: Causes of secondary adrenal insufficiency
`
`Diagnosis
`Pituitary tumours
`
`Other tumours of the
`hypothalamic-pituitary
`region
`Pituitary irradiation
`
`Lymphocytic hypophysitis
`Isolated
`
`As part of APS
`
`Isolated congenital
`ACTH deficiency
`Pro-opiomelanocortin-
`deficiency syndrome
`Combined pituitary-
`hormone deficiency
`
`Pituitary apoplexy
`Sheehan’s syndrome
`Pituitary infiltration
`or granuloma
`Head trauma
`Previous chronic
`glucocorticoid excess
`
`Comment
`Secondary adrenal insufficiency mostly as part of panhypopituitarism, additional symptoms (visual-field
`impairment): generally adenomas, carcinoma is a rarity; consequence of tumour growth, surgical
`treatment, or both
`Craniopharyngioma, meningioma, ependymoma, and intrasellar or suprasellar metastases
`
`Craniospinal irradiation in leukaemia, radiation for tumours outside the hypothalamic-pituitary axis,
`irradiation of pituitary tumours
`
`Autoimmune hypophysitis; most frequently in relation to pregnancy (80%48); mostly hypopituitarism,
`but also isolated adrenocorticotropic hormone deficiency
`Associated with autoimmune thyroid disease and, less frequently, with vitiligo, primary gonadal failure,
`type 1 diabetes, and pernicious anaemia49
`Pro-opiomelanocortin cleavage enzyme defect?50
`
`Pro-opiomelanocortin gene mutations;51 clinical triad adrenal insufficiency, and early-onset obesity, red
`hair pigmentation
`Mutations in the gene encoding the pituitary transcription factor Prophet of Pit1 (PROP1),52
`progressive development of panhypopituitarism in the order GH, PRL, TSH, LH/FSH, (ACTH)
`Mutations in the homeo box gene HESX1,53 combined pituitary hormone deficiency, optic-nerve
`hypoplasia, and midline brain defects (septo-optic dysplasia)
`Onset mainly with abrupt severe headache, visual disturbance, and nausea or vomiting54
`Pituitary apoplexy or necrosis with peripartal onset—eg, due to high blood loss or hypotension
`Tuberculosis, actinomycosis, sarcoidosis, histiocytosis X, Wegener’s granulomatosis
`
`For example pituitary stalk lesions
`Exogenous glucocorticoid administration for more than 4 weeks55 endogenous glucocorticoid
`hypersecretion due to Cushing’s syndrome
`
`GH=growth hormone. PRL=prolactin. TSH=thyrotropin. LH=luteinising hormone. FSH=follicle stimulating hormone.
`
`The main symptom of chronic adrenal insufficiency is
`fatigue, accompanied by lack of stamina, loss of energy,
`reduced muscle strength, and
`increased
`irritability.
`
`Additionally, chronic glucocorticoid deficiency leads to
`weight loss, nausea, and anorexia (anorexia or failure to
`thrive in children), and can account for muscle and joint
`
`Panel 3: Clinical manifestations of adrenal insufficiency
`
`Symptoms
`Fatigue, lack of energy or stamina, reduced strength
`Anorexia, weight loss (in children failure to thrive)
`Gastric pain, nausea, vomiting (more frequent in primary
`adrenal insufficiency)
`Myalgia, joint pain
`Dizziness
`Salt craving (primary adrenal insufficiency only)
`Dry and itchy skin (in women)
`Loss or impairment of libido (in women)
`Signs
`Skin hyperpigmentation (primary adrenal insufficiency only)
`Alabaster-coloured pale skin (secondary adrenal insufficiency only)
`Fever
`Low blood pressure (systolic RR <100 mm Hg), postural
`hypotension (pronounced in primary adrenal insufficiency)
`Raised serum creatinine (primary adrenal insufficiency only)
`Hyponatraemia
`
`Hyperkalaemia (primary adrenal insufficiency only)
`Anaemia, lymphocytosis, eosinophiliia
`Increased thyroid stimulating hormone (primary adrenal
`insufficiency only)
`Hypercalcaemia (primary adrenal insufficiency only)
`Hypoglycaemia
`Loss of axillary or pubic hair (in women), absence of adrenarche or
`pubarche in children
`
`RR=R-R interval. SIADH=syndrome of inappropriate antidiuretic hormone secretion.
`
`Pathophysiology
`Glucocorticoid deficiency, adrenal androgen deficiency
`Glucocorticoid deficiency
`Glucocorticoid deficiency, mineralocorticoid deficiency
`
`Glucocorticoid deficiency
`Mineralocorticoid deficiency, glucocorticoid deficiency
`Mineralocorticoid deficiency
`Adrenal androgen deficiency
`Adrenal androgen deficiency
`
`Excess of pro-opiomelanocortin-derived peptides
`Deficiency of pro-opiomelanocortin-derived peptides
`Glucocorticoid deficiency
`Mineralocorticoid deficiency, glucocorticoid deficiency
`
`Mineralocorticoid deficiency
`Mineralocorticoid deficiency, glucocorticoid deficiency
`(leading to SIADH)
`Mineralocorticoid deficiency
`Glucocorticoid deficiency
`Glucocorticoid deficiency (or autoimmune thyroid failure)
`
`Glucocorticoid deficiency (mostly concurrent hyperthyroidism)
`Glucocorticoid deficiency
`Adrenal androgen deficiency
`
`1884
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`MYLAN PHARMS. INC. EXHIBIT 1098 PAGE 4
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`

`

`Physiological situation
`
`SEMINAR
`
`Primary adrenal insufficiency
`
`Adrenal
`
`Adrenal
`
`AI, II
`
`AI, II
`
`Kidney
`
`Kidney
`
`Renin
`
`Aldosterone
`
`Renin
`
`Aldosterone
`
`these
`pain. Unfortunately, most of
`symptoms are non-specific. Thus, 50% of
`patients have signs and symptoms of
`Addison’s disease for more than 1 year
`before diagnosis
`is
`established.58
`In
`secondary adrenal insufficiency, diagnosis is
`generally prompted by a history of pituitary
`disease, but can also be delayed—eg, in
`isolated ACTH deficiency. A more specific
`sign of primary adrenal
`failure
`is
`hyperpigmentation, which
`is most
`pronounced in areas of the skin exposed to
`increased
`friction—eg, palmar creases,
`knuckles,
`scars,
`oral
`mucosa.
`Hyperpigmentation is caused by enhanced
`stimulation of skin MC1-receptor by
`ACTH and other pro-opiomelanocortin-
`related peptides. Accordingly, patients with
`secondary adrenal insufficiency often have
`pale, alabaster-coloured skin. Laboratory
`findings in glucocorticoid deficiency can
`include mild anaemia, lymphocytosis, and
`eosinophilia. Cortisol
`physiologically
`inhibits
`thyrotropin
`release. Thus,
`concentration of
`thyrotropin
`is often
`increased at initial diagnosis of primary
`adrenal
`insufficiency, but returns to normal during
`glucocorticoid replacement unless there is coincident
`autoimmune
`thyroid dysfunction.59
`In
`rare cases,
`glucocorticoid deficiency can result in hypercalcaemia,
`which is due to increased intestinal absorption and
`decreased renal excretion of calcium and generally
`coincides with autoimmune hyperthyroidism, facilitating
`calcium release from bone.60
`Mineralocorticoid deficiency, which is present only in
`primary adrenal
`insufficiency
`(figure 2),
`leads
`to
`dehydration and hypovolaemia, resulting in low blood
`pressure, postural hypotension, and sometimes even in
`prerenal failure. Deterioration can be sudden and is often
`due to exogenous stress such as infection or trauma.
`Combined mineralocorticoid
`and
`glucocorticoid
`replacement in primary disease reconstitutes the diurnal
`rhythm of blood pressure61
`and
`reverses cardiac
`dysfunction.62 Glucocorticoids
`contribute
`to
`this
`improvement not only by mineralocorticoid receptor
`binding, but also by permissive effects on catecholamine
`action.63 The
`latter could account
`for the relative
`unresponsiveness to catecholamines
`in patients with
`unrecognised adrenal crisis. Mineralocorticoid deficiency
`accounts for hyponatraemia (90% of patients with primary
`adrenal insufficiency), hyperkalaemia (65%), and salt
`craving (15%).1,6 Low serum sodium values can also be
`present in secondary adrenal insufficiency due to syndrome
`of inappropriate antidiuretic hormone secretion, which
`results from the loss of physiological inhibition of pituitary
`vasopressin release by glucocorticoids.64
`Adrenal
`insufficiency
`inevitably
`leads to dehydro-
`epiandrosterone deficiency. Dehydroepiandrosterone is the
`major precursor of sex-steroid synthesis and loss of its
`production results in pronounced androgen deficiency in
`women. As a consequence, women with adrenal
`insufficiency frequently show loss of axillary and pubic hair
`(absence of pubarche in children), dry skin, and reduced
`libido. Dehydroepiandrosterone also exerts direct action as
`a neurosteroid with potential antidepressant properties.57
`Thus dehydroepiandrosterone deficiency could contribute
`to the impairment of wellbeing noted in patients with
`adrenal insufficiency despite adequate glucocorticoid and
`mineralocorticoid replacement.65
`
`Potassium excretion
`Sodium retention
`Fluid retention
`
`Potassium retention
`Sodium loss
`Fluid depletion
`
`Mineralocorticoid production
`AI, II=Angiotensin I and II.
`
`Laboratory assessment of adrenal function
`(panel 4)
`Concentrations of ACTH and cortisol vary throughout the
`day due to their closely related pulsatile release, which
`follows a diurnal rhythm. Therefore, the diagnostic
`usefulness of random samples is limited. Moreover, total
`cortisol, but not the biologically active free fraction, can
`increase as a result of hepatic cortisol-binding globulin
`production, which
`is
`increased,
`for example, by
`oestrogens.66 Finally, differences in cortisol assays can
`affect normative data and interpretation of dynamic tests.67
`
`Primary adrenal insufficiency
`The combined measurement of early morning serum
`cortisol and plasma ACTH separates patients with primary
`adrenal insufficiency from healthy individuals and from
`those with secondary disease.68 Plasma ACTH is usually
`greatly increased and invariably higher than 22·0 pmol/L,
`with serum cortisol generally lower than the normal range
`(<165 nmol/L) but sometimes in the lower normal range.
`Serum aldosterone concentrations are subnormal or within
`the lower normal range, with plasma renin activity
`concurrently increased above the normal range.68
`In
`patients who have adrenal insufficiency, serum dehy-
`droepiandrosterone is consistently low,69,70 and in women is
`often lower than the limit of detection.
`The impaired ability of the adrenal cortex to respond to
`ACTH is readily demonstrated by the standard short
`corticotropin test,71 which involves measurement of serum
`cortisol before and after 30 or 60 min intravenous or
`intramuscular injection of 250 ␮g 1-24 ACTH.66,72 In
`healthy individuals, this challenge leads to a physiological
`increase in serum cortisol to peak concentrations of greater
`than 500 nmol/L.67
`In those with primary adrenal
`insufficiency, in whom the adrenal cortex is already
`maximally stimulated by endogenous ACTH,68 exogenous
`hormone administration usually does not evoke any further
`increase in serum cortisol.
`Adrenal cortex autoantibodies or antibodies against
`21-hydroxylase are present in more than 80% of patients
`with recent onset autoimmune adrenalitis.73 Although
`21-hydroxylase has been
`identified as
`the major
`autoantigen in autoimmune adrenalitis,74 autoantibodies
`
`1885
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`
`

`

`SEMINAR
`
`Panel 4: Biochemical diagnosis of adrenal insufficiency
`
`Test
`
`Protocol
`
`Normal range
`
`Definitive
`adrenal
`insufficiency
`
`Adrenal insufficiency Comment
`not excluded
`
`Primary adrenal insufficiency
`Early morning
`Serum cortisol at
`cortisol
`0700–0900 h
`and
`Early morning
`ACTH
`
`Plasma
`ACTH at
`0700–0900 h
`
`Standard short
`corticotropin test
`
`Serum cortisol at
`0, 30, and 60 min
`after 250 µg intra-
`venous or intra-
`muscular 1-24 ACTH
`
`165–680 nmol/L Cortisol
`<165 nmol/L
`and
`1·1–11·0 pmol/L ACTH
`>22·0 pmol/L
`
`Cortisol
`<300 nmol/L
`
`Cortisol >500 nmol/L usually
`excludes primary adrenal
`insufficiency*
`ACTH in most cases
`>45·0 pmol/L*
`
`Peak cortisol
`>500 nmol/L
`
`Peak cortisol
`<500 nmol/L
`
`In most cases no cortisol
`increase because of already
`maximum endogenous
`ACTH stimulation
`
`165–680 nmol/L Cortisol
`<100 nmol/L
`
`1·1–11·0 pmol/L
`
`Cortisol >100 nmol/L Cortisol >500 nmol/L excludes
`or <500 nmol/L
`secondary adrenal insufficiency
`ACTH
`<11·0 pmol/L
`Peak cortisol
`<600 nmol/L
`
`Peak cortisol <400nmol/L in
`most patients with secondary
`adrenal insufficiency
`
`Peak cortisol
`<500 nmo/L
`
`Secondary adrenal insufficiency
`Early morning
`Serum cortisol at
`cortisol
`0700–0900 h
`Early morning
`Plasma ACTH
`ACTH
`at 0700–0900 h
`Peak cortisol
`Standard short
`Serum cortisol at
`corticotropin test
`0 and 30 or 60 min >500 nmol/L
`after 250 µg
`intravenous or
`intramuscular 1-24
`ACTH
`Serum glucose and Peak cortisol
`cortisol 0, 15, 30,
`>500 nmol/L
`45, 60, and 90 min
`after intravenous
`insulin (0·1–0·15
`U/kg)
`
`Insulin tolerance
`test
`
`Peak cortisol
`<500 nmol/L
`
`Peak cortisol
`<550 nmol/L
`
`Test only valid if symptomatic
`hypoglycaemia (serum glucose
`<2·2 nmol/L) is achieved; gold
`standard test; close
`supervision mandatory;
`contraindicated with history of
`seizures, cerebrovascular, and
`cardiovascular disease
`
`*Researchers’ laboratory; normal values vary dependent on laboratory and assay.
`
`against other steroidogenic enzymes (P450scc, P450c17)
`and steroid-producing cell antibodies are present in some
`patients.12 Measurement of autoantibodies is especially
`helpful
`in patients with
`isolated primary adrenal
`insufficiency and no family history of autoimmune
`disease. In APS type 2, autoimmune adrenalitis can be
`associated with autoimmune thyroid disease or type 1
`diabetes, and screening for concomitant disease should
`involve measurement of thyrotropin and fasting glucose
`but not of other organ-related antibodies.
`In boys and men with
`isolated primary adrenal
`insufficiency without
`unequivocal
`evidence
`of
`autoimmune adrenalitis, serum concentrations of very-
`long-chain fatty acids (chain length of ⭓24 carbons;
`C26, C26/C22, and C24/C22 ratios) should be measured
`to exclude adrenoleukodystrophy or adrenomyeloneu-
`ropathy.16
`
`Secondary adrenal insufficiency
`Baseline hormone measurements differ little between
`patients with secondary adrenal insufficiency and healthy
`individuals.16,68 However, a morning cortisol value below
`100 nmol/L indicates adrenal insufficiency whereas a
`serum cortisol greater than 500 mmol/L is consistent with
`an intact hypothalmic-pituitary-adrenal axis.72,75,76 Thus, in
`most
`instances, dynamic tests of the hypothalmic-
`pituitary-adrenal axis are required to establish a diagnosis
`of secondary adrenal insufficiency.
`
`The insulin tolerance test77 is regarded as the gold
`standard in the assessment of suspected secondary
`adrenal
`insufficiency, since hypoglycaemia (blood
`glucose <2·2 mmol/L) is a powerful stressor that results
`in rapid activation of the hypothalamic-pituitary-adrenal
`axis.66 An intact axis is indicated by a peak cortisol of
`more than 500 nmol/L at any time during the test
`(panel 4).78,79 Occasionally, however, a patient will pass
`the insulin tolerance test despite exhibiting clinical
`evidence for adrenal insufficiency that responds to
`hydrocortisone substitution.80 A higher cut-off value
`(550 nmol/L) for peak cortisol in the insulin tolerance
`test could help to reduce misclassification.79,81 During the
`test, close supervision is mandatory66 and cardiovascular
`disease or history of seizures are contraindications.
`Another diagnostic test is the overnight metyrapone
`test (metyrapone 30 mg/kg [maximum 3 g] administered
`with a snack at midnight).82,83 Metyrapone inhibits
`adrenal 11␤-hydroxylase—ie,
`the
`conversion of
`11-deoxycortisol to cortisol. In healthy individuals,
`feedback activation of the hypothalmic-pituitary-adrenal
`axis increases serum 11-deoxycortisol, while serum
`cortisol
`remains at concentrations of
`less
`than
`230 nmol/L. In patients with secondary adrenal
`insufficiency, however, 11-deoxycortisol does not
`exceed 200 nmol/L at 0800 h after metyrapone.
`Shortcomings of the test are limited availability of
`reliable 11-deoxycortisol assays and the need to order
`
`1886
`THE LANCET • Vol 361 • May 31, 2003 • www.thelancet.com
`For personal use. Only reproduce with permission from The Lancet Publishing Group.
`
`MYLAN PHARMS. INC. EXHIBIT 1098 PAGE 6
`
`

`

`metyrapone directly from the manufacturer (Novartis,
`Basel, Switzerland). Since metyrapone can precipitate
`adrenal crisis in severe cortisol deficiency, a morning
`cortisol concentration of more than 200 nmol/L should
`be recorded before doing the test on an out patient
`basis.66
`Because both the insulin tolerance test and the
`metapyrone test pose a great burden to patients and
`doctors, there have been continuing efforts to replace
`these tests by more convenient ones.78,84–86 Sustained
`secondary adrenal insufficiency leads to adrenal atrophy
`and also to reduced ACTH receptor expression in the
`adrenal gland, since ACTH up-regulates
`its own
`receptor.87 Thus adrenal responsiveness to an acute
`exogenous ACTH challenge
`is
`impaired also
`in
`secondary disease, facilitating the use of the standard
`short corticotropin test for the assessment of axis
`integrity (panel 4). Several studies72,88 have reported
`excellent
`agreement
`between
`peak
`cortisol
`concentrations in the standard short corticotropin test
`and in the insulin tolerance test. However, some patients
`with secondary adrenal insufficiency do pass the standard
`short corticotropin test but not the insulin tolerance
`test.89–91 The use of a higher cut-off value (600 nmol/L)
`for passing the corticotropin test could keep to a
`minimum the risk of overlooking secondary disease.92
`Thus the standard short corticotropin test obviates the
`insulin tolerance test in a substantial proportion of
`patients with suspected secondary adrenal insufficiency.
`Since the administration of 250 ␮g 1-24 ACTH repre-
`sents a massive supraphysiological challenge, a low-dose
`corticotropin test that uses only 1 ␮g ACTH has been
`proposed as a more sensitive test for the diagnosis of
`secondary adrenal insufficiency.93–96 The test has been
`successfully used to monitor recovery of adrenal function
`after withdrawal of oral glucocorticoids11 and to detect
`subtle impairment of adrenal reserve during inhaled
`steroid
`therapy.97,98 However,
`the
`intravenous
`administration of 1 ␮g ACTH still results in hormone
`concentrations greater than those required for maximum
`cortisol release.99 Accordingly, in healthy individuals,
`serum cortisol concentrations measured 30 min after the
`challenge do not differ between the standard short
`corticotropin test and the low-dose corticotropin test.
`Results of several studies, co