Endocrine surgery

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CHAPTER 11 Endocrine surgery

Thyroid 178

Parathyroids 188

Adrenal gland 189

Multiple endocrine neoplasia (MEN) 193

Thyroid

Congenital

The embryological line of descent of the thyroid gland is from the foramen caecum of the tongue to its normal position in the neck. Occasionally, it may descend lower and even to the superior mediastinum.

Lingual thyroid

This occurs at the foramen caecum of the tongue. It may be asymptomatic or interfere with speech or swallowing. A radio-iodine scan should be performed to confirm the presence of thyroid tissue. Treatment is by suppression of TSH with thyroxine, but surgical excision should be considered if hormonal therapy is ineffective or the patient has obstructive symptoms.

Thyroglossal fistula

This is not congenital but follows rupture, or inadequate excision of a thyroglossal cyst. Recurrent inflammation occurs and the fistula intermittently discharges mucus. Treatment is by excision of the fistula and may require dissection as far as the foramen caecum of the tongue.

Thyroglossal cyst (→ Ch. 8)

Examination of the thyroid gland

Inspection should be carried out initially from the front. Confirm that there is a mass in the neck in the area of the thyroid gland and that it moves up on swallowing. Place a finger in the suprasternal notch and check that the trachea is central. Examine the thyroid from behind. Place the thumbs on the vertebra prominens and the fingers on the anterior part of the neck on either side. Allow the head to tilt forwards slightly to relax the neck muscles. Feel up and down in the area of the thyroid. Applying gentle pressure to one side of the neck over the thyroid facilitates examination of the contralateral lobe. Decide whether there is a single nodule, many nodules or whether there is diffuse enlargement of the thyroid gland.

Give the patient a glass of water to swallow and check again that the gland moves up on swallowing. Palpate up and down the deep cervical chain of lymph nodes to check for lymphadenopathy. Try to get below the lower limit of the thyroid swelling to exclude retrosternal extension. Percussion over the sternum to check for retrosternal extension is inaccurate and outdated. In patients with Graves’ disease auscultate over the gland. Very vascular toxic glands may have a systolic bruit.

Symptoms of thyroid disease

Investigation of thyroid dysfunction/swellings

Patients can be euthyroid, hyperthyroid or hypothyroid. Measure TSH, free T4, free T3, thyroid antibodies. TSH is elevated in hypothyroidism. TSH is suppressed in thyrotoxicosis. Thyroid autoantibodies suggest immune aetiology of disease.

Fine needle aspiration

This will distinguish between a solid lesion and a cyst. If the lesion is solid, cells are sent for cytological examination. This is a safe technique. Usually it is possible to discriminate benign from malignant disease, although some difficulties may be encountered. In particular, cytology cannot distinguish between benign and malignant follicular lesions. Fine needle biopsy should be performed in the investigation of all thyroid nodules. Its reliability can be improved by carrying out the biopsy under ultrasound guidance.

Plain radiograph of chest thoracic inlet

May show tracheal displacement or compression. Retrosternal extension.

Ultrasound scan

It establishes the size and shape of the gland and indicates if nodules are single or multiple and their size. It will also distinguish between cystic and solid lesions.

Radioisotope scans

These are only helpful in some patients with thyrotoxicosis. In Graves’ disease the uptake is increased and diffuse. In toxic nodular goitre the uptake is patchy and multiple or unifocal depending on the pathology.

Goitre

A goitre is an enlargement of the thyroid gland (for Classification → Table 11.1).

TABLE 11.1 Classification of goitres

Simple (non-toxic goitre)

Simple hyperplastic goitre Multinodular goitre

Toxic goitre

Diffuse (Graves’ disease) Toxic nodule (adenoma) Toxic multinodular goitre

Neoplastic goitre

Benign:

Malignant:

Inflammatory De Quervain’s thyroiditis
Riedel’s thyroiditis Autoimmune Hashimoto’s thyroiditis

Simple hyperplastic goitre

Iodine deficiency is the commonest pathological cause. Physiological causes include puberty and pregnancy. Endemic goitres occur in childhood and are common in areas where the drinking water has a low iodine content. They are rare in the UK where iodide is added to table salt.

Multinodular goitre

This is the commonest cause of goitre in the UK. The gland is enlarged and irregular. The condition develops spontaneously and also in simple colloid goitres. There are areas of hypoplasia and hyperplasia within the gland. The condition is more common in women. With large glands, tracheal deviation and compression may occur. Toxic change may occasionally occur with the symptoms of hyperthyroidism.

Toxic goitre

This may be a diffuse goitre (Graves’ disease), toxic multinodular goitre or solitary toxic adenoma. In Graves’ disease, TSH receptor antibodies are present. In toxic multinodular goitre, several nodules in a non-toxic goitre begin to function independently of TSH. A solitary toxic nodule functions autonomously. Toxic goitre is six times more common in females.

Symptoms and signs

Hyperthyroidism, tachycardia, palpitations, AF, tremor, increased tendon reflexes. In Graves’ disease – exophthalmos, lid lag, pretibial myxoedema. Occasionally bruit over gland.

Investigations

• Low TSH; free T4 (↑); free T3 (↑)

• Isotope scan may show ‘hot’ nodules.

Treatment

Antithyroid drugs

For the patient with Graves’ disease, carbimazole 40 mg daily as ‘blocking’ dose until euthyroid and then 5 mg t.d.s. for 12–18 months or continue ‘block’ and ‘replace’ with thyroxine. About 50% of patients with Graves’ disease remain euthyroid when the drug is discontinued. Severely toxic patients may require β-blockers until euthyroid. Relapses, if they happen, usually occur within 2 years of stopping treatment. Hypothyroidism may develop. Side-effects of carbimazole include rashes and neutropenia – patients must be warned to report any sore throat or mouth ulcers occurring, especially in the initial stages of carbimazole treatment. Patients with thyrotoxicosis due to toxic multinodular goitre/toxic adenoma, can be rendered euthyroid with antithyroid drugs but require definitive treatment with radio-iodine or surgery.

Radio-iodine

¹³¹I is administered orally. It usually takes 8–12 weeks before the patient becomes euthyroid. After the ¹³¹I is given, antithyroid drugs need to be taken until the symptoms settle. It is appropriate treatment for most patients with thyrotoxicosis, recurrent hyperthyroidism, and poor-risk patients. It should not be used in children and pregnant women because of potential radiation hazards. There is a high incidence of late myxoedema.

Surgery

This is the treatment of choice for younger patients, children and patients with large goitres. The patient should be rendered euthyroid prior to surgery with antithyroid drugs. Blocking therapy with carbimazole, and replacing endogenous hormone production with thyroxine administration is optimum preparation for surgery. Propranolol may be needed if control is difficult to achieve or when urgent surgery may be indicated. Total thyroidectomy is the preferred procedure. Thyroid lobectomy is the appropriate treatment for a solitary toxic nodule.

Prognosis

Hypothyroidism may occur after radioactive iodine and will occur after surgery. If subtotal resection is performed, about 4% remain toxic and around 8–10% will become toxic again at a later time. ¹³¹I treatment is then appropriate. About 4% become hypothyroid immediately and up to 60% may ultimately become hypothyroid. This depends on the dose of radioactive iodine. At the low dose, 10% become hypothyroid at 1 year then cumulatively 3% per year become hypothyroid. With bigger doses (ablative), up to 60% become hypothyroid at 1 year. Lifelong monitoring of thyroid function is required.

Neoplastic goitre

Benign

Adenomas

True follicular adenomas are encapsulated and are usually >2 cm on presentation. They are solid on ultrasound and ‘cold’ on isotope scans. FNAC will not distinguish them from follicular carcinoma. They must be excised. Lobectomy is adequate treatment.

Malignant

The large majority are primary tumours. Aetiological factors include exposure to ionizing radiation in childhood; endemic goitre (iodine deficiency) may be associated with follicular carcinoma but the risk is small. There is also a rare association with adenomatous colonic polyps. Papillary cancer may be associated with an autosomal dominant family history. Family history may be present in patients with medullary carcinoma associated with MEN Type II. Metastatic carcinoma to the thyroid is rare but may spread via the bloodstream from breast, lung, kidney and prostate. The main types of thyroid cancer are as follows.

Differentiated (papillary and follicular)

Papillary (60%)

Papillary occurs at any age with a peak incidence in the third and fourth decades. Usually a slow-growing nodule, which may metastasize early to regional lymph nodes. They are often multicentric within the thyroid gland. The tumour is TSH dependent. The condition of ‘lateral aberrant thyroid’ more correctly represents secondary deposit of papillary carcinoma in lymph nodes.

Follicular carcinoma (20%)

Follicular carcinoma has a peak incidence in the 40–60 age group. It spreads via the blood stream. Distant metastasis is normally to lung and bone. Occasionally, the disease presents with bony secondaries.

Anaplastic carcinoma (5–8%)

Occurs in old age. Usually rapidly growing and locally invasive, with early spread via the lymphatics and bloodstream to lungs, bone and brain. Stridor, dysphagia, recurrent laryngeal nerve palsy may occur.

Medullary carcinoma (5%)

May present at any age. Arises from parafollicular C cells. Secretes calcitonin. Presents with solitary nodule or mass and may spread to cervical nodes. It may be familial (25%) and associated with MEN Type II. Even in the absence of a family history, screening for mutations of the ret-proto-oncogene on chromosome 10 is necessary. When present, family screening is indicated. Prophylactic thyroidectomy may be offered in gene-positive individuals.

Lymphoma (5%)

May be diagnosed on FNAC or core biopsy. There is an increased incidence of lymphoma originating in the thyroid in Hashimoto’s thyroiditis.

Symptoms and signs of malignant goitres

Patients are usually euthyroid. Rarely is the patient toxic. Differentiated thyroid cancer (i.e. papillary and follicular) usually presents with a thyroid nodule. Cervical nodes may be enlarged and there may be local discomfort in the neck. Bone pain may represent secondary disease and may be the presenting symptom. Cough may be due to lung metastases. Medullary carcinoma may be familial and associated with MEN. Anaplastic carcinoma occurs in the elderly. There will be a hard craggy mass, which may be locally invasive with lymph node involvement. Stridor, dysphagia, pain, and hoarseness may occur.

Investigations

• FNAC is the mainstay of preoperative investigation

• CXR: lung metastases

• Bone scan if bone pain

• Ultrasound scan for lymphadenopathy

• Calcitonin levels if medullary carcinoma suspected

• When medullary cancer is present, phaeochromocytoma must be excluded and the serum calcium checked.

Treatment

• Well-differentiated (papillary/follicular) Total thyroidectomy and excision of all involved nodes. ¹²³I diagnostic scanning for secondary disease and ¹³¹I ablation treatment. Life-long thyroxine treatment is required as (1) replacement therapy and (2) to achieve TSH suppression. Thyroglobulin estimations should be carried out 6-monthly as a marker of recurrent disease. Subsequent ¹³¹I therapy may be used for secondary disease – although bony secondaries are best treated with external beam irradiation.

• Anaplastic Surgery is rarely indicated. Response to radiotherapy is poor. Chemotherapy is usually ineffective. Surgical debulking to relieve pressure on the trachea and oesophagus may allow palliation.

• Medullary Total thyroidectomy with removal of all affected lymph nodes. Follow-up includes regular calcitonin levels. Detectable calcitonin levels suggest residual or recurrent tumour which should be sought and removed surgically. Recurrence of high calcitonin levels suggests tumour recurrence. These should be sought and removed surgically. Inoperable tumours should be irradiated.

• Lymphoma Treatment depends upon the type and is a matter for a specialist in lymphoma treatment.

Prognosis

• Differentiated (papillary/follicular). Prognosis can be excellent. Around 9% of patients will die of the disease and 30% will need treatment for nodal/secondary disease. Adverse prognostic factors include increasing age (especially over 40) at first presentation, male gender, extrathyroidal and metastatic spread.

• Anaplastic. Poor prognosis – 1-year survival is <10%.

• Medullary. The prognosis is variable. With nodal metastases the 10-year survival is <50%.

Inflammatory conditions of the thyroid

These are rare.

Subacute thyroiditis (de Quervain’s)

This is a self-limiting condition associated with giant cells and granulomata. Symptoms include pain, swelling, enlarged tender thyroid, malaise, myalgia. The ESR is raised. Aspirin and steroids give symptomatic relief. The acute symptoms last 10–14 days.

Riedel’s thyroiditis

This is a woody hard goitre that infiltrates into the adjacent muscle. It may compress the trachea and may be associated with retroperitoneal fibrosis. It must be differentiated from anaplastic carcinoma. Surgery is necessary occasionally to confirm the diagnosis and to relieve pressure on the oesophagus and trachea. Tamoxifen treatment is associated with reduction in the size of the goitre.

Thyroidectomy

Indications

These are suspected or proven malignancy, thyrotoxicosis, tracheal/oesophageal compression, cosmetic for unsightly goitre.

Preoperative preparation

Thyrotoxic patients should be rendered euthyroid preoperatively. The vocal cords should be checked preoperatively. A very few patients may show an unsuspected vocal cord paralysis preoperatively. This is an important consideration in view of possible intraoperative recurrent laryngeal nerve damage. The patient should be warned of possible nerve damage. Permanent injury occurs in 1–2% of thyroidectomies but possibly as often as 10% in re-exploration procedures. A warning should be given regarding hypocalcaemia, which is usually a transient problem. It will be seen in about 30% of cases of total thyroidectomy with about 2% of patients still requiring replacement therapy at 3 months postoperatively.

Operations

The following operations are appropriate: solitary benign nodule requires lobectomy; cancer requires total thyroidectomy; thyrotoxicosis or large multinodular goitre requires subtotal or total thyroidectomy. Total thyroidectomy is increasingly the operation of choice.

Procedure

Principles of thyroidectomy

• General anaesthesia with endotracheal intubation

• Sandbag under shoulders and head positioned on a ring. Neck extended. Table foot down

• Skin crease incision about two fingers breadth above the sternal notch. The incision should reach the sternocleidomastoid on each side

• Raised skin flaps (including subcutaneous fat and platysma) to the thyroid notch superiorly and the sternal notch inferiorly. Flaps may then be held by a self-retaining retractor (Joll’s retractor)

• Make a vertical incision through the deep fascia between the strap muscles and retract the strap muscle. If the goitre is large, the strap muscles are divided at their upper extremity because their nerve supply enters the lower part of the muscles

• Divide the middle thyroid veins

• Draw down the upper pole and identify the superior thyroid vessels

• Ligate the superior thyroid vessels close to the upper pole of the thyroid to avoid the external branch of the superior laryngeal nerve

• Draw the lobe of the thyroid gland medially and dissect the lateral connective tissue and identify the inferior thyroid artery

• Identify the recurrent laryngeal nerve

• Ligate the inferior thyroid artery in continuity lateral to the recurrent laryngeal nerve

• Ligate the inferior thyroid veins

• The lobe is now free and may be removed by dividing the isthmus, disconnecting it off the trachea and oversewing the isthmus with catgut

• If only carrying out a lobectomy, oversew the thyroid remnant to the trachea

• Meticulous haemostasis

• Suture the deep fascia between the strap muscles

• Close the wound in layers with suction drainage.

Complications

Haemorrhage

This may cause airway obstruction. Treatment is by opening the wound, evacuating the haematoma and securing haemostasis. This may need to be done on the ward. Instruments to remove clips or stitches must be within ready reach in the postoperative period.

Laryngeal oedema

It may occur with or without compression from a haematoma. Stridor and respiratory distress occur. Intubation is required. The condition usually settles spontaneously.

Nerve damage

Recurrent laryngeal nerve

Damage to this may be unilateral, bilateral, temporary, or permanent. Unilateral injury usually causes hoarseness. If this is due to neuropraxia, the voice usually returns to normal within 3 months. If damage is bilateral, airway obstruction occurs after extubation – repeat intubation or emergency tracheostomy is required. If injury is permanent, tracheostomy will be permanent. Laser arytenoidectomy to lateralize the vocal cords is an alternative.

Superior laryngeal nerve

This may result in variable degrees of huskiness or weakness of the voice with change in volume and pitch. Singers, actors and others who rely on their voice professionally should be warned of this possible complication.

Thyroid storm (thyrotoxic crisis)

Seen rarely nowadays, because of better preoperative preparation. Hypercatabolic state due to uncontrolled thyrotoxicosis – usually in an inadequately prepared patient who is undergoing surgery for thyrotoxicosis. Symptoms include hyperpyrexia, confusion, restlessness, sweating, arrhythmias. Treatment includes propranolol, hydrocortisone and potassium iodide.

Hypocalcaemia

Tetany may occur because of ischaemia, or removal, of the parathyroids. Usually occurs within 2–5 days postoperatively. Symptoms include circumoral paraesthesia with tingling of the extremities. Chvostek’s sign (tap the facial nerve in front of the external auditory meatus – with hypocalcaemia the side of the face will twitch). In severe hypocalcaemia, painful carpopedal spasms and spasm of respiratory muscles may occur. Treatment is by slow infusion of 10 mL 10% calcium gluconate followed by oral calcium administration. Usually, calcium therapy is needed for a limited period of time – up to 3 months – but long-term management will require 1α-vitamin D. This is also sometimes needed in the short term if hypocalcaemia is profound. Occasionally, parathyroid recovery can be very slow – taking up to 2 years. Calcium levels must be monitored to avoid hypercalcaemia developing.

Wound infection

This is rare.

Recurrent thyrotoxicosis

Hypothyroidism

Keloid scar

Parathyroids

Hyperparathyroidism is the most common clinical disorder of the parathyroid glands. Ischaemia to the parathyroid glands may occur during thyroid surgery and result in hypoparathyroidism.

Hyperparathyroidism

Three types occur: primary, secondary and tertiary.

Primary hyperparathyroidism

This may result from a parathyroid adenoma (85%), diffuse parathyroid hyperplasia (15%) and, rarely, from carcinoma of the parathyroid. Hyperparathyroidism is the commonest component of MEN I syndrome.

Differential diagnosis

Need to exclude other causes of hypercalcaemia, e.g. malignancy, myeloma, sarcoidosis, milk-alkali syndrome. PTH is normal or low in these conditions.

Treatment

Surgery is the treatment of choice. Some surgeons consider preoperative localization of the glands, concordant ultrasound and MIBI scans allowing a focused neck exploration to identify and remove only abnormal parathyroid tissue. If localization studies are not performed or are negative, all four glands should be identified at operation. Occasionally, there are three, five or even six glands. A parathyroid adenoma is removed. If there is hyperplasia of all glands, 3½-gland parathyroidectomy is performed. The residual gland should be marked with a surgical clip. When abnormal parathyroid tissue cannot be found in the neck, or in the superior mediastinum explored through the neck, the need for mediastinal exploration through a sternotomy should be considered. This should only be done after the missing gland has been identified by venous sampling, isotope studies, or CT/MRI scanning. The missing gland may not be in the chest – it may be intrathyroidal. Parathyroidectomy is an operation for the experienced surgeon doing this type of surgery on a regular basis. Even so, an additional parathyroid gland may be overlooked and further surgery required. Hypoparathyroidism may occur postoperatively.

Secondary hyperparathyroidism

This usually occurs in patients with chronic renal failure, although it may be seen in any situation that results in low serum calcium. Hypocalcaemia results in stimulation of the parathyroids with resulting hyperplasia. Patients in CRF are unable to synthesize vitamin D and develop hypocalcaemia, hypophosphataemia, and impaired calcium absorption.

Symptoms and signs

These are of CRF. Bone pain, pruritus, metastatic extravascular calcification. Serum calcium is normal.

Treatment

Correct the underlying cause. In CRF, patients require aluminium hydroxide to reduce phosphate, vitamin D, calcium supplements and high-calcium dialysate. Surgery is required in patients refractory to medical treatment with bone pain, pruritus and metastatic calcification.

Tertiary hyperparathyroidism

Hyperparathyroidism that persists in patients who have had successful renal transplants. Serum calcium is high. The parathyroid hyperplasia of long-term renal disease becomes autonomous despite the return of calcium levels to normal. The symptoms are those of secondary hyperparathyroidism. Treatment is by subtotal parathyroidectomy.

Adrenal gland

The adrenal gland consists of an outer cortex and an inner medulla. The adrenal cortex may overfunction because of hyperplasia or tumour. This may result in an overproduction of glucocorticoids (Cushing’s syndrome) or mineralocorticoids (Conn’s syndrome). The most common tumour of the adrenal medulla is a phaeochromocytoma, which secretes adrenaline and noradrenaline. Adrenal insufficiency (Addison’s disease) may be primary or due to tuberculosis, metastatic disease, adrenal haemorrhage or withdrawal after long-term steroid therapy.

Adrenal cortex

Cushing’s syndrome

This is the result of increased secretion of cortisol. Cushing’s disease results from overproduction of ACTH by the pituitary resulting in bilateral adrenocortical hyperplasia. Cushing’s syndrome refers to increased secretion of cortisol of any origin and includes adrenal adenoma, adrenal carcinoma, administration of exogenous corticosteroids, as well as ectopic ACTH secretion, e.g. oat cell bronchial carcinoma.

Symptoms and signs

The presentation is variable. Any or all of the following may occur: truncal obesity, buffalo hump, moon face, proximal myopathy of the limbs, skin striae, acne, hirsutism, capillary fragility with bruising, oedema, hypertension, osteoporosis, psychiatric disturbances, diabetes, peptic ulceration, pancreatitis, cataracts, skin pigmentation, avascular necrosis of bone.

Treatment

If the symptoms are due to adenoma or carcinoma, the affected adrenal gland is removed. For bilateral hyperplasia, with ACTH suppression, bilateral adrenalectomy is indicated with permanent replacement steroid therapy. For pituitary tumours, pituitary surgery is required. This may be done by transphenoidal resection or an yttrium implant. For ectopic ACTH secretion, the source should be excised if possible, e.g. pneumonectomy for oat cell carcinoma of the lung. In inoperable cases, radiotherapy may be useful. Bilateral adrenalectomy may be required to control the symptoms. Metyrapone, which inhibits cortisol production, may also be beneficial in cases not amenable to surgery.

Primary hyperaldosteronism

There is excessive secretion of aldosterone with suppression of plasma renin. It is more common in females. The condition is usually due to unilateral adenoma (Conn’s syndrome) or bilateral hyperplasia. Rarely bilateral adenomas or carcinoma. The primary type must be distinguished from secondary hyperaldosteronism where there is an increased plasma renin due to increased activity of the renin–angiotensin mechanism. This may occur in renal artery stenosis, cirrhosis, CCF or nephrotic syndrome.

Adrenal medulla

Phaeochromocytoma

This is a catecholamine-producing tumour that arises from the chromaffin cells of the adrenal medulla or other sympathetic nervous tissue, e.g. aortic paraganglia. Some 10% are malignant and may be associated with other genetically determined conditions, e.g. MEN Type II, neurofibromatosis Type I, von Hippel–Lindau disease and the paraganglioma syndromes (SDH). Patients less than 40 years of age should be genetically screened.

Symptoms and signs

Paroxysmal hypertension. Headaches, palpitations, sweating, pallor, dyspnoea, anxiety, chest pain, weakness.

Investigations

• Blood sugar

• 24-hour urine for catecholamines and metanephrines

• CT scanning will locate 90% (→ Fig. 11.2)

• ¹³¹I-metaiodobenzylguanidine scanning (MIBG).

Figure 11.2 An abdominal CT scan showing a large phaeochromocytoma (arrow) in the left adrenal gland.

Treatment

Surgical excision. Preoperative stabilization required. α-Adrenergic blockade with phenoxybenzamine. Treatment should be given prior to surgery until nasal stuffiness and postural hypotension occur. High dosage may need to be gradually introduced to block the adrenergic effects of the tumour. If required, β-blockade with propranolol should be used only when α-blockade is complete. Any diabetogenic effect of the tumour should be controlled – often with insulin. Occasionally phaeochromocytomas can present acutely with cardiac arrhythmias, hypotensive episodes, encephalopathy and coma. Haemorrhagic rupture of the tumour may occur with shock. In these cases, α-adrenergic blockade with i.v. phentolamine followed by emergency surgery.

Adrenal insufficiency

This may be primary (Addison’s disease) when adrenal destruction may be autoimmune, or due to sarcoidosis, tuberculosis, amyloidosis, secondary deposits, adrenal haemorrhage (anticoagulant therapy) or meningococcal septicaemia (Waterhouse–Friderichsen syndrome); or secondary due to pituitary disease or withdrawal of long-term steroid therapy. Bilateral adrenalectomy is an iatrogenic cause.

Symptoms and signs

Acute adrenal insufficiency

Shock, nausea, vomiting, hyperpyrexia, rigors, abdominal pain, coma.

Chronic adrenal insufficiency

Anorexia, lethargy, malaise, hypotension, weight loss, constipation, amenorrhoea, hyperpigmentation of skin.

Investigations

• If the patient is already on steroid therapy, check that the dose is adequate

• Check BP

• U&Es: K⁺ ↑ Na⁺ ↓, blood sugar ↓, serum cortisol levels reduced with inadequate response to synacthen test

• ACTH levels high in Addison’s disease and low in secondary causes

• Adrenal antibody screen

• CXR: may show TB

• AXR: adrenal gland calcification in TB.

Treatment

The acute case requires resuscitation with i.v. saline and hydrocortisone 100 mg i.v. 6-hourly. Clinical improvement is often dramatic. Chronic adrenal insufficiency is treated with oral hydrocortisone t.d.s. at a weight-related dose. Fludrocortisone as mineralocorticoid replacement (0.5–1.0 mg daily) is indicated in most patients. Fatigue, hypotension, and hyperkalaemia are signs of undertreatment. Hypertension, oedema, and hypokalaemia are signs of overtreatment. Patients on replacement therapy should be warned that increased doses are required at times of stress, e.g. surgery or an acute illness. Care should be taken in reducing steroids and discontinuing them in patients who have been on long-term therapy, e.g. for asthma or rheumatoid arthritis. In these patients, gradual withdrawal over weeks will allow endogenous steroid production to resume but in others, signs of insufficiency will appear.

Adrenal incidentaloma

An incidentaloma is a mass lesion found unexpectedly in an adrenal gland by an imaging procedure performed for reasons other than suspected adrenal pathology. The vast majority are non-secretory benign lesions. Once discovered, the question is, are they benign or malignant and are they hypersecretory?

Carcinoma of the adrenal gland

Adrenocortical carcinoma is rare but aggressive. It is potentially curable in the early stages but only 30% are confined to the adrenal gland at the time of diagnosis; 10% of phaeochromocytomas are malignant and occur within the adrenal medulla. Secondary deposits are more common than primary tumours, the adrenal glands being the fourth most common site of metastases after lungs, liver and bone. The most common primary sites are lung, breast, skin (melanoma), kidney, thyroid and colon.

Multiple endocrine neoplasia (MEN)

MEN syndromes are patterns of endocrine disease inherited as autosomal dominant traits. A family history should be taken in all patients presenting with hyperparathyroidism, medullary thyroid cancer, phaeochromocytoma and pancreatic endocrine tumours.

MEN I

Manifestations are hyperparathyroidism (>90%), pancreatic tumours (>30%) with malignant potential (insulinomas, gastrinomas) and pituitary tumours (prolactinoma).

Symptoms and signs

Hyperparathyroidism may be asymptomatic and detected incidentally on checking Ca²⁺ levels. Patients can present with symptoms related to peptic ulceration (gastrinoma) or to the pituitary tumour.

Treatment

Directed at the tumours.

MEN IIa

Manifestations are medullary carcinoma of the thyroid (100%), phaeochromocytoma (30–50%) and parathyroid hyperplasia (rare).

Symptoms and signs

All patients with medullary carcinoma of the thyroid should undergo ret-mutation analysis. If a mutation is detected, family screening is necessary. If positive in the family, e.g. parents, children, brothers, sisters (and their progeny) – prophylactic thyroidectomy must be considered. Search should be made for all tumours in the syndrome prior to treatment.

Treatment

If phaeochromocytoma is located, treat this first. Then deal with thyroid and parathyroid at the same operation.

MEN IIb

Manifestations are medullary carcinoma of the thyroid, phaeochromocytoma, multiple mucosal neuromas and marfanoid habitus.

Symptoms and signs

Early appearance of marfanoid habitus and mucosal neuromas suggests diagnosis. Medullary thyroid cancer arises in the first year of life. Other symptoms are as for Type IIa. It occurs in first and second decades. Other symptoms are as for Type IIa.

Treatment

MEN IIb presents more aggressively than Type IIa and therefore prompt diagnosis and treatment are required.

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Endocrine surgery

Thyroglossal cyst (→ Ch. 8)

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