Dr.Amanj
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PARATHYROID
Primary hyperparathyroidism;-
*Adenoma (75-90%) * Hyperplasia (20-24%) * Carcinoma, rare (1%)
Indications for parathyroidectomy
Severe symptoms
Young age group
Markedly reduced bone density
Serum calcium more than 11 mg%
Urinary calculi
Neuromuscular presentations
Urinary calcium more than 400 mg /24 hours
Complications of parathyroid surgery include ;-
Permanent hypoparathyroidism
Persistent hyperparathyroidism—5%
Recurrent hyperparathyroidism—hypercalcaemia recurs 12months after fi rst
parathyroid surgery
Recurrent laryngeal nerve injury—1%
Often needs additional thyroidectomy
Variations in positions of the gland especially lower-may be in mediastinum
Sudden drop in calcium level after surgery due to increased absorption of
calcium by bones—hungry bone syndrome
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Parathyroid carcinoma;-
is rare.
Typical features are
1-very high calcium and PTH levels,
2- palpable neck swelling or
3- occasionally lymphadenopathy.
.
Scanning may support the diagnosis
-
diagnosis ;
The diagnosis is rarely known at the time of exploration .
-
;
Treatment
1-operation should include excision of the tumour mass with en bloc thyroid
lobectomy and node dissection when indicated.
2-Adjuvant or palliative radiotherapy may be indicated.
Recurrent hyperparathyroidism
Recurrent HPT is diagnosed when hypercalcaemia recurs more than 12 months
after an initially curative operation.
This may occur because of:
1• missed pathology at the first operation;
2• (rarely) development of a second adenoma;
3• hyperplasia in autotransplanted tissue;
4• parathyromatosis (disseminated nodules of parathyroid tissue within the
soft tissues of the
neck and superior mediastinum caused by rupture of abnormal parathyroid
tissue at initial
surgery).
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HYPOPARATHYROIDISM
Causes ;-
1- rare congenital (DiGeorge) and medical (autoimmune polyglandular and
Wilson) syndromes .
2-Postoperative hypoparathyroidism .(This results from trauma to or removal
or
devascularisation of the parathyroid glands, which may be deliberate but is
more often inadvertent.
Symptoms and signs
*The symptoms and signs of acute hypoparathyroidism are related to the level
of serum
calcium and range from mild circumoral and digital numbness and
paraesthesia to tetanic
symptoms with carpopedal or laryngeal spasms, cardiac arrhythmias and fits.
*Chronic hypoparathyroidism can lead to abnormal bone demineralisation,
cataracts,
calcification in basal ganglia and consequent extrapyramidal disorders.
*Percussion of the facial nerve just below the zygoma causes contraction of
the ipsilateral facial muscles
(Chvostek’s sign).
*Carpopedal spasm can be induced by occlusion of the arm with a blood
pressure cuff for
3 min
(Trousseau’s sign).
*Electrocardiogram changes include prolonged QT intervals and QRS complex
changes.
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Management of postoperative hypocalcaemia
*Acute symptomatic hypocalcaemia is a medical emergency and requires
urgent correction by ;-
1-intravenous injection of calcium./Magnesium supplements may also be
required.
2-Oral calcium (1 g three or four times daily) supplemented by1–3 μg daily of
1- alpha-vitamin D if necessary should be given with a view to gradual
withdrawal over
the next 3–12 months.
■ Check serum calcium within 24 hours of total thyroidectomy or earlier if
symptomatic
■ Medical emergency if the level is < 1.90 mmol l–1:
* Correct with 10 ml of 10% calcium gluconate intravenously;
*10 ml of 10% magnesium sulphate intravenously may also be required.
■ Give 1 g of oral calcium three or four times daily.
■ Give 1–3 μg daily of oral 1-alpha-vitamin D if necessary.
ADRENAL CORTICAL TUMOURS
Are usually adenomas.
Any tumour measuring 6 cm or more are likely to be malignant, or have high
risk of turning into
malignancy. So requires surgical resection.
Adenocarcinoma is the commonest adrenal cortical malignancy (1%).
It is very aggressive tumour.
Cortical tumours may be functioning or nonfunct ioning.
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Functioning tumours secrete mineralocorticoids, glucocorticoids or sex
hormones or combinations of these.
Investigations
U/S abdomen.
CT scan, Hormone evaluation.
Treatment
Adrenalectomy
Incidentalomas (3-5%)
Incidentalomas are adrenal tumours incidentally identified either through
U/S; CT scan; MRI; or any
other methods done for other reasons.
When incidentalomas are identified a proper biochemical work up for
hormones is essential.
Overnight dexamethasone suppression test; 24-hour urinary cortisol excretion
assay; 24-hour urinary
excretion of catecholamines; serum potassium, renin and aldosterone analysis
are done in these
patients. MRI in suspected malignancy is better.
If secondaries are suspected adrenal mass biopsy is done.
Otherwise it should not be done. Non-functioning adenomas (commonest—
78%), Cushing’s
adenoma, Adrenocortical carcinoma, phaeochromocytoma, secondaries,
Conn’s adenoma are different causes of adrenal incidentalomas.
Adenoma with Cushing’s syndrome is better than adenoma with Conn’s
syndrome. Tumour with
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Adrenogenital syndrome is commonly malignant.
Non-functioning adrenal tumour more than 4 cm should be operated. Smaller
tumours that increase
In size over specified period should be removed. All functioning tumours
should be operated.
Non-functioning tumour less than 4 cm should be followed up at regular
intervals by hormone tests and CT/MRI.
ADRENOCORTICAL CARCINOMA
It is a rare malignancy. It is common in females with bimodal presentation.
Presentations are—
abdominal pain; back pain; Cushing’s syndrome;
hyperaldosteronism;virilisation.
Can be functioning or nonfunctioning tumour.
Larger tumours (>6 cm) are more likely to be malignant.
Often presents with no symptoms or only vague symptoms.
May present with mass effect and compression of adjacent structures.
Increased secretion of one or more steroid hormones can occur.
Diagnosis is by—
hormone evaluation, CT/MRI; MR angiography to identify IVC
tumour thrombus.
Secondaries occur commonly in lungs. So HRCT of lungs is usually done.
Treatment
is en block adrenalectomy; Adjuvant radiotherapy may be used to
prevent recurrence.
Recurrence is treated by debulking and chemotherapy.
Laparoscopic adrenalectomy is not advisable in adrenocorticalcarcinoma.
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Approches for adrenals (surgical)
Posterior lumbotomy
Anterior transabdominal
Abdominothoracic
Laparoscopic
Retroperitoneoscopic
PHEOCHROMOCYTOMA
It is a tumour arising from chromaffin cells, commonly from the adrenal
medulla but occasionally can
arise from extraadrenal chromaffin tissues (Organ of Zuckerkandl).
It is catecholamine secreting tumours .
In patients with hypertension it is up to 0.6%. 4% of Incidentalomas are
pheochromocytoma.
Extra-adrenal pheochromocytoma—10 % common; occurs in organ of
Zuckerkandl, urinary bladder,
paravertebral or para-aortic area, thorax, neck. It secretes norepinephrine
rather than epinephrine because they lack the enzyme PNMT.
Commonly benign (90%).
Tumour is
10% malignant 10% extraadrenal 10% bilateral 10% familial 10%
childhood
10% multiple 10% not associated with hypertension 10% calcified
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Differential diagnosis
Hyperthyroidism
Anxiety status
Cardiac conditions
Carcinoids (functioning)
Investigations
1- VMA excretion in urine in 24 hours will be >7 mg/24 hr in
pheochromocytoma.
2- U/S abdomen, IVU, CT scan.
3-MRI is preferred to CT as contrast used for CT scan can precipitate
paroxysms.
4- Measurement of plasma free metanephrines is the recommended test of
choice for excluding or confi rming diagnosis of pheochromocytoma.
5-Urinary normetadrenaline or other catecholamines estimation.
6- Arteriography.
7- Iodine labelled metaiodobenzylguanidine (I, MIBG). MIBG is useful to fi nd
out extraadrenal involvement—SPECT scan is very useful. I131 MIBG scan is
safe, noninvasive with
100% sensitivity and 95% specificity.
Measurement of plasma free metanephrine and normetanephrine has the
highest sensitivity and specifi city and appears to be the best initial test for
screening patients with pheochromocytoma
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Remember
Pheochromocytoma is rarely malignant in MEN II Pheochromocytoma under
40 years of age suspect MEN 2A, VHL
Beta-blocker is given only after patient is fully alpha blocked with
phenoxybenzamine (20-60 mg/day) or doxazocin Alpha-blocker is given 4
weeks prior to surgery to control hypertension and beta-blocker is given one
week before surgery to control tachycardia and arrhythmias
Tumours, those secrete dopamine exclusively has got high malignant chances
5-year survival for malignant pheochromocytoma is 50%.
It needs additional chemotherapy using vincristine, dacarbazine and
cyclophosphamide
Pheochromocytoma in pregnancy has got 50% maternal mortality
Vaginal delivery is contraindicated in pregnancy with pheochromocytoma
Adrenal vein should be ligated fi rst Avoid breach in the capsule of tumour
during surgery Careful handling and haemodynamic monitoring is a must
Sodium nitroprusside may be required on table to control the hypertension—
10 μg/kg/minute