The suprarenal glands
The suprarenal (adrenal) glands arepaired glands situated above and
medial to the upper pole each kidney.
The cortex derives from the
mesoderm of the urogenital ridge,
while the medulla derives from neural
crest ectoderm.
´Physiology
´ Suprarenal cortex´ The suprarenal cortex secretes three groups of steroids:
1 glucocorticoids , which regulate carbohydrate metabolism, protein breakdown and fat
mobilization;
2 androgenic corticoids , which are virilizing;
3 mineralocorticoids , which regulate mineral and water metabolism. Aldosterone acts to
retain sodium and water and to excrete potassium.
´ Suprarenal medulla
´ The suprarenal medulla is richly innervated with sympathetic preganglionicb fibres,
and produces
! the catecholamines adrenaline (epinephrine) and
! noradrenaline (norepinephrine) in response to autonomic stimulation.
Pathology
The main pathologies are increased function, owing to tumour o rhyperplasia;
decreased function, owing to atrophy, infarction or removal; or abnormal function,
owing to enzyme disorders.
Increased f unction
• Glucocorticoids (Cushing ’ s syndrome):
• Androgenic corticoids : virilism (the adrenogenital syndrome).
• Mineralocorticoids : primary hyperaldosteronism (Conn ’ s syndrome)
• Catecholamines : phaeochromocytoma.
Decreased function
Hypoadrenalism is most commonly a sequel of a
´ prolonged corticosteroid therapy, in which endogenous
steroid production is suppressed, followed by abrupt
steroid withdrawal.
´ • congenital suprarenal hypoplasia;
´ • autoimmune destruction: Addison ’ s disease; 1
´ • suprarenal infarction : a rare consequence of stress or
sepsis (notably meningococcal sepsis);
´ • bilateral adrenalectomy : intentionally (to treat Cushing ’ s
syndrome) or secondary to bilateral nephrectomy;
´ • suprarenal infi ltration by secondary tumours from primaries
in bronchus and breast;
´ • bilateral tuberculosis of the suprarenals
´Incidentaloma
Definition
Incidentaloma is an adrenal mass, detected incidentally by imaging studies
conducted for other reasons, not known previously to have been present or
causing symptoms
´ Prevalence of non-functioning and functioning tumours in
´ patients with incidentalomas. Tumour Prevalence (%)
Non-functioning adenoma 78
Cushing’s adenoma 7
Adrenocortical carcinoma 4
Phaeochromocytoma 4
Myelolipoma 2
Cyst 2
Metastases 2
Conn’s adenoma 1
diagnosis
´ History and clinical examination
´ hormonal assey
´ • morning and midnight plasma cortisol measurements;
´ • a 1-mg overnight dexamethasone suppression test;
´ • 24-hour urinary cortisol excretion;
´ • 12 or 24-hour urinary excretion of metanephrines or plasmafree
metanephrines;
´ • serum potassium, plasma aldosterone and plasma renin activity;
´ • serum DHEAS, testosterone or 17-hydroxyestradiol (virilising or
feminising tumour).
´ Computed tomography (CT) or magnetic resonance imaging (MRI) should
be performed in all patients with adrenal masses.
´ biopsy
!Cushing ’ s syndrome
! Cushing ’ s syndrome 2 is produced by increased circulating corticosteroids.
! Excepting therapeutic exogenous steroid administration, the majority of cases result from a pituitary
adenoma producing ACTH, resulting in hyperplasia of the suprarenal cortex
! The syndrome usually affects young adults
! women more often than men.
Clinical features of Cushing’s syndrome
Weight gain/central obesity
Diabetes
Hirsutism
Hypertension
Skin changes (abdominal striae, facial plethora,ecchymosis, acne)
Muscle weakness
Menstrual irregularity/impotence
Depression/mania
Osteoporosis
Hypokalaemia
Diagnosis
• Morning and midnight plasma cortisol levels are elevated,possibly with loss of diurnal
rhythm.
• Dexamethasone fails to suppress 24-hour urinary cortisol excretion.
• Serum ACTH levels discriminate ACTH-dependent from ACTH-independent disease.
´ Elevated or normal ACTH levels provide evidence for an ACTH-producing pituitary
tumour (85 per cent) or ectopic ACTH production.
´ Therefore, in patients with elevated ACTH, MRI of the pituitary gland must be
performed.
Treatment:
´Medical therapy with metyrapone or ketoconazole reduces
steroid synthesis and secretion and can be used :
´ to prepare patients with severe hypercortisolism
preoperatively or
´ if surgery is not possible.
´ ACTH-producing pituitary tumours are treated by trans-sphenoidal
resection or radiotherapy.
´ If an ectopic ACTH source is localised, resection will correct
hypercortisolism.
´ A unilateral adenoma is treated. by adrenalectomy
´ In cases of bilateral ACTH-independent disease bilateral
adrenalectomy is the primary treatment.
Preoperative management
Patients with Cushing’s syndrome are at an increased risk of hospitalacquired
infection, thromboembolic and myocardial complications.
Therefore, prophylactic anticoagulation and the use of
prophylactic antibiotics are essential
Postoperative management
After unilateral adrenalectomy supplemental cortisol should be given postoperatively because the
contralateral gland willbe suppressed.
In total, 15 mg/hour is required parenterally for the first 12 hours followed by a daily dose of 100
mg for 3 days,which is gradually reduced thereafter.
After unilateral adrenalectomy,the contralateral suppressed gland needs up to one year
to recover adequate function.
Primary hyperaldosteronism(Conn’s syndrome)
Conn ’ s syndrome 3 is a rare syndrome produced by an aldosterone - secreting adenoma of the
suprarenalcortex.
Characteristically, there is a low serum potassium.
Clinical features
! Most patients are between 30 and 50 years of age
! with a femalepredominance.
! Apart from hypertension, patients complain of
! non-specific symptoms: headache, muscle weakness, cramps,intermittent paralysis, polyuria,
polydypsia and nocturia
! Special i nvestigations
• Serum electrolytes : hypernatraemia and hypokalaemia.
• Plasma aldosterone : the diagnosis is confi rmed by demonstration of excess aldosterone in the
plasma.
• Abdominal CT may demonstrate the tumour, which is often small.
• Selective angiography and selective venous sampling from the suprarenal veins with
aldosterone estimations may be needed to delineate the lesion.
Treatment
1. The first-line therapy for PHA with bilateral hyperplasia is medical
treatment with spironolactone.
In most cases supplemental antihypertensive medication is necessary.
2.Unilateral laparoscopic adrenalectomy is an effective therapy in
patients with clear evidence of unilateral or asymmetrical bilateral disease
3. A subtotal resection can be considered in thecase of a typical single
Conn’s adenoma.
4. In 10–30 per cent of patients who undergo an adrenalectomy,
hypertension persists despite adequate diagnostic work-up and treatment,