Postoperative complications
HaemorrhageA tension haematoma deep to the cervical fascia is usually due
to reactionary haemorrhage from one of the thyroid arteries;
occasionally, haemorrhage from a thyroid remnant or a thyroid
vein may be responsible. This is a rare but desperate emergency
which requires urgent decompression by opening the layers of
the wound, not simply the skin closure, to relieve tension before
urgent transfer to theatre to secure the bleeding vessel
Respiratory obstruction
This is very rarely due to collapse or kinking of the trachea
(tracheomalacia). Most cases are due to laryngeal oedema. The
most important cause of laryngeal oedema is a tension haematoma.
If releasing a tension haematoma does not immediately
relieve airway obstruction, the trachea should be intubated at
once.
Recurrent laryngeal nerve paralysis and voice change
Recurrent laryngeal nerve injury may be unilateral or bilateral,transient or permanent. . Injury to the external branch of the
superior laryngeal nerve is more common because of its proximity
to the superior thyroid artery. This leads to loss of tension in
the vocal cord with diminished power and range in the voice.
Patients, particularly those who use their voice professionally,
must be advised that any thyroid operation will result in change
to the voice even in the absence of nerve trauma
Thyroid insufficiency
Following subtotal thyroidectomy this usually occurs within two
Years .
Parathyroid insufficiency
This is due to removal of the parathyroid glands or infarction
through damage to the parathyroid end artery; often, both factors
occur together. and most cases present dramatically 2–5 days after operation
Thyrotoxic crisis (storm)
This is an acute exacerbation of hyperthyroidism. It occurs if a
thyrotoxic patient has been inadequately prepared for thyroidectomy
and is now extremely rare. Very rarely, a thyrotoxic patient
presents in a crisis and this may follow an unrelated operation.
Symptomatic and supportive treatment is for dehydration,
hyperpyrexia and restlessness. This requires the administration
of intravenous fluids, cooling the patient with ice packs,
administration of oxygen, diuretics for cardiac failure, digoxin
for uncontrolled atrial fibrillation, sedation and intravenous
hydrocortisone. Specific treatment is by carbimazole 10–20 mg
6-hourly, Lugol’s iodine 10 drops 8-hourly by mouth or sodium
iodide 1 g i.v. Propranolol intravenously (1–2 mg) or orally
(40 mg 6-hourly) will block _-adrenergic effects
Wound infection
Cellulitis requiring prescription of antibiotics A significant subcutaneous or deep cervical abscess is exceptionally rare and should be drained
Hypertrophic or keloid scar
This is more likely to form if the incision overlies the sternumand in dark-skinned individuals
Stitch granuloma
This may occur with or without sinus formation and is seen
after the use of non-absorbable, particularly silk, suture material.
. NEOPLASMS OF THE THYROID
Classification of thyroid neoplasms.
Benign
Adenoma Follicular
Malignant
Primary
Differentiated Follicular epithelium –
Follicular
Papillary
Follicular epithelium – undifferentiated
Anaplastic
Parafollicular cells Medullary
Lymphoid cells Lymphoma
Secondary Metastatic
Local infiltration
Relative incidence (%)
Papillary carcinoma 60
Follicular carcinoma 20
Anaplastic carcinoma 10
Medullary carcinoma 5
Malignant lymphoma 5
Benign tumours
Follicular adenomas present as clinically solitary nodules
and the distinction between a follicular carcinoma and
an adenoma can only be made by histological examination; in
the adenoma there is no invasion of the capsule or of pericapsular
blood vessels. Treatment is, therefore, by wide excision,
i.e. lobectomy.
Malignant tumours
The vast majority of primary malignancies are carcinomas
derived from the follicular cells . Dunhill classified
them histologically as differentiated and undifferentiated:
and the differentiated carcinomas are subdivided into follicular
and papillary. Lymphoma and medullary cancers make up the
remainder of primary malignancies. Metastases to the thyroid,
most commonly from kidney and breast, are rare. Direct invasion
by upper aerodigestive squamous cancer is a rare but lethal
event. Lymph node and blood-borne metastases to bone and
lung occur and may be the mode of presentation
Aetiology of malignant thyroid tumours
The single most important aetiological factor in differentiated
thyroid carcinoma, particularly papillary, is irradiation of the thyroid under five years of age The incidence of follicular carcinoma is high in endemic goitrous areas ,Malignant lymphomas sometimes develop in in autoimmune thyroiditis
Clinical features of thyroid cancers
The annual incidence is about 3.7 per 100 000 of the population
and the sex ratio is three females to one male, The most common presenting symptom is a thyroid swelling. Enlarged cervical lymph nodes may be the presentation of papillary carcinoma. Recurrent laryngeal nerve paralysis is very suggestive of locally advanced disease
Anaplastic growths are usually hard, irregular and infiltrating.
A differentiated carcinoma may be suspiciously firm and irregular,
but is often indistinguishable from a benign swelling. Small
papillary tumours may be impalpable, even when lymphatic
metastases are present
Diagnosis of thyroid neoplasms
Diagnosis is obvious on clinical examination in most cases of
anaplastic carcinoma . . It is not alway easy to exclude a carcinoma in a multinodular goitre, and solitary nodules, particularly in the young male, are always suspect.
Failure to take up radioiodine is characteristic of almost all thyroid
carcinomas . TSH levels are often raised in carcinoma
. The key role of FNAC in preoperative diagnosis
has already been discussed. There is a false-negative rate with
all investigations, and lobectomy is appropriate when there is a
strong clinical suspicion. Incisional biopsy may cause seeding of
cells and local recurrence, and is not advised in a resectable carcinoma.
In an anaplastic and obviously irremovable carcinoma, , imaging with either ultrasound or MRI is required . As well as additional information on the extent of the primary, this will give valuable information on nodal involvement to permit preoperative planning for nodal dissection
Prognosis in differentiated thyroid carcinoma
The prognosis in differentiated thyroid carcinoma compared to most cancers is excellent
Although influenced by histological type, prognosis is much more dependent on age at diagnosis, size of the tumour, metastatic disease
Surgical treatment
Patients with large, locally aggressive or metastatic differentiated thyroid cancer (DTC) require total thyroidectomy with excision of adjacent involved structures if necessary followed by radioiodine ablation with long-term TSH suppression
Additional measures:
Thyroxine
It is standard practice to prescribe thyroxin in a dose of 0.1–0.2 mg daily, to suppress endogenous TSH production, for all patients after operation for differentiated thyroid carcinoma on the basis that most tumours are TSH dependent
Radioiodine
If metastases take up radioiodine, they may be detected by scanningand treated with large doses of radioiodine
Thyroglobulin
The measurement of serum thyroglobulin is invaluable in the follow up and detection of metastatic disease in patients who have undergone surgery for differentiated thyroid cancer. it can be used after lobectomy
Undifferentiated (anaplastic) carcinoma
They are extremely lethal tumours and survival is calculated in months
Complete resection is justified if the disease appears confined to the thyroid
Medullary carcinoma
These are tumours of the parafollicular (C cells) the neural crest and not from the cells of the thyroid follicleHigh levels of serum calcitonin and carcinoembryonic
antigen are produced by many medullary tumours.
Calcitonin levels fall after resection and rise again with recurrence making it a valuable tumour marker in the follow up of patients with this disease
Treatment is by total thyroidectomy and either prophylactic or therapeutic resection of central and bilateral cervical lymph nodes
Malignant lymphoma
The prognosis is good if there is no involvement of cervical lymph nodes. Rarely the tumour is part of widespread malignant lymphoma and the prognosis in these cases is worse .