a recurrence of this infection. Patients with active tuberculosis (TB) lose weight, complain of feeling tired, have night sweats and are breathless. They have a chronic cough with blood in the sputum (haemoptysis).
Transmission of TB is usually by droplets but occasionally from infected, non - pasteur- ised milk. Healing may take place and the only sign in later life is calcifi ed nodes on a lung x - ray. Progression of TB may occur through blood spread to involve other organs or re - activation of a previous infection, seen in the lungs as cavitation.
Patients with active disease (positive sputum) or who are still coughing should not receive dental care, except for dental emergencies. Most patients will have negative sputum cultures after three to four weeks of treatment and are then not infective. Non - compliance with drug therapy, which takes months, is the usual cause of a prolonged infective period.
hormone. Over - production during the growing period results in gigantism, while under - production produces a dwarf. In the adult, over - production results in gigantism at the extremities – acromegaly. The patient may complain that dentures no longer fi t.
Accompanying signs and symptoms are sweating, heart disease and diabetes.
The other relevant hormone secreted by the pituitary is antidiuretic hormone (ADH) which regulates the uptake of water via the kidney and helps control fl uid balance.
Failure to do this produces diabetes insipidus and the affected patient loses litres of urine per day and drinks excessively. This is managed by DDAVP (see p. 109).
Aspects of o ral and d ental s ignifi cance In hyperpituitarism :
■ precocious dental development ■ osteoporosis
■ thickening of facial and cranial base bony structures ■ hypercementosis.
In hypopituitarism :
■ delayed dental development
■ alteration in the facial skeleton and cranial base dimensions ■ anterior open bite
■ link with adrenal and thyroid function may precipitate a hypopituitary coma in response to stress.
Thyroid g land
This gland is situated at the base of the neck with a lobe either side of the trachea. Its activity is controlled by thyroid - stimulating hormone (TSH) from the pituitary gland.
This is regulated by the amount of thyroid hormone in the blood, which feeds back to the pituitary so preventing over - or under - production. The thyroid hormone plays a central part in regulating the metabolic rate.
Goitre
The thyroid gland can be prominent in cases of goitre. The hormone thyroxine is made up in part of iodine; if there is insuffi cient iodine in the diet there is under - production of thyroxine. The pituitary gland then receives less circulating thyroxine and so produces more TSH, causing the gland to eventually enlarge. This is corrected by adding iodine to table salt in areas where such a defi ciency would otherwise occur.
More commonly, such effects are seen nowadays in young women and may be related to oestrogen because they are commonly seen at times of hormonal upheaval such as the onset of menstruation or pregnancy. Other goitres are due to an adenoma.
Thyroiditis may also occur due to viral infections or autoimmune disease – Hashimoto ’ s
thyroiditis. Malignant tumours can occur and are treated by thyroidectomy or injection of radioactive iodine.
Hypofunction
Congenital hypothyroidism, called cretinism, is rare in the UK because of screening at birth. In adults it may occur due to autoimmune disease, surgical removal or a defect in the pituitary control. Patients complain of feeling cold and weight gain. They seem lethargic, slow and look puffy, particularly around the eyes. The effects on the heart are slowing of the rate (bradycardia), and an increase in blood cholesterol eventually results in ischaemic heart disease. Such patients are treated by thyroxine and care must be used in administering LA containing epinephrine. These patients respond poorly to stress and infection.
Hyperfunction
Hyperfunction is usually due to an autoimmune disorder – Graves ’ disease. This is seen mainly in young women. The effects of auto - antibodies also produce the characteristic eye effect – proptosis (forward positioning of eyeball, i.e. protuberant) – as a result of the reduction in intra - ocular volume. The signs and symptoms are the opposite of those seen in hypothyroidism, namely weight loss, increased heart rate (tachycardia), agitation and tremor, and intolerance to heat. Stress, trauma or acute infection can bring on a thyroid storm (thyrotoxic crisis) if the condition is not stable.
Parathyroid g lands
The function of these glands is of relevance to dentistry because they are involved in the control of calcium and phosphate levels. The four glands are situated at the back of the thyroid glands. Their activity is not controlled by the pituitary, like other glands, but by the levels of calcium in the blood.
Parathyroid hormone (PTH) promotes:
■ increased absorption of calcium from the intestines
■ increased retention of calcium, by action in the renal tubules ■ osteoclastic activity in bone, releasing calcium into the blood ■ increased excretion of phosphates by the kidney.
Hyperparathyroidism
PTH excess is usually as a consequence of a tumour. This produces demineralisation of bone and large cyst - like areas appear on a radiograph. Fractures may occur. Because high levels of calcium and phosphate are being excreted through the kidneys, calculi (renal stones) may develop.
Hypoparathyroidism
Lack of PTH means that calcium is not readily mobilised from bone and blood levels fall.
In the growing child this happens rapidly as calcium is taken up into developing bone.
As well as bone, calcium is involved in other cells in the body; it plays a very important role in keeping cell membranes intact. In the absence of calcium, cell membranes become more permeable, and in muscles, depolarisation occurs spontaneously and the fi bres twitch and go into spasm. This is called tetany . Tetany produces tingling and cramps, spasm of the hands and seizures. Tetany is also seen in alkalosis. Hysterical patients may hyperventilate, losing excess carbon dioxide (CO 2), producing alkalosis and tetany.
Reassurance and re - breathing expired air (breathing in and out of a paper bag) will help to re - establish normal CO 2 levels.
Oral and d ental e ffects
■ Anterior open bite and class II skeletal base relationships.
■ Delayed dental development, spaced dentitions.
■ Enamel hypoplasia.
Adrenal g lands
The two glands are situated on top of the kidneys. The outer portion of each gland (cortex) produces steroid hormones and the inner part (medulla) produces epinephrine and norepinephrine.
Adrenal c ortex
Adrenocorticotrophic hormone (ACTH) secreted by the pituitary stimulates the adrenal cortex to produce steroid hormones, which are responsible for glucose metabolism. The most common of these are cortisone and hydrocortisone, and they act in the opposite way to insulin, i.e. by increasing blood glucose. These hormones also play a part in sup- pressing the immune system. The other steroid hormones produced are responsible for sodium and potassium metabolism (aldosterone) and for secondary sexual characteristics (testosterone and oestrogen), although most testosterone and oestrogen is produced by the testes and ovaries respectively.
Hypofunction (Addison ’ s d isease)
Hyposecretion is as a result of autoimmune destruction of the gland, steroid therapy, surgical removal or problems with the pituitary gland. Patients will complain of tired- ness, weakness, may appear confused and, in the longer term, will have weight loss.
Sodium and potassium handling is altered so patients will complain of thirst all the time.
A patient may have a heart attack because of these raised levels of potassium or because of arrhythmias.
Oral and d ental c onsiderations
■ Patients may feel faint on sitting up from the dental chair.
■ Patients respond poorly to the stress of infections or dental procedures.
■ There may be pigmentation of the gums (due to stimulation of melanocytes).
It is vital to consult the patient ’ s physician to determine what additional steroids should be given to cover any dental procedures and where these procedures should be carried out.
Hyperfunction (Cushing ’ s s yndrome)
Hyperfunction arises as a consequence of overproduction of ACTH from, for example, a pituitary or adrenal tumour or because of chronic high - dose steroids such as those used for immunosuppression after transplantation.
Patients have classic rounded ( moon ) faces and an increase in body fat accompanied by muscle wasting, especially of the arms and legs. Women show an increase in facial hair. Sodium and therefore water is retained. Such a clinical presentation could be con- fused with obese alcoholics.
Oral and d ental c onsiderations
■ Patients who have been on courses of steroids are in danger of a steroid crisis if exposed to stressful situations because they are unable to produce suffi cient of their own as a consequence of wasting of the adrenal gland. Patients for whom this applies must be covered adequately for stressful dental procedures. It is sensible to discuss the proposed dental treatment with the patient ’ s doctor/physician, who may feel it advisable to prescribe an antibiotic because of the immunosuppression and the likely consequences of postoperative infection. Treatment under sedation can be useful to allay anxiety. The normal daily output of hydrocortisone is 20mg, therefore patients taking low doses for short time periods are unlikely to need supplementation.
■ Patients who are on larger doses or for longer periods should, in consultation with their physician, double the daily dose on the morning of dental treatment, up to the normal physiologic output of adrenal glands (20mg/day). Higher doses ( > 40mg/day) of prednisolone would not normally require a supplemental dose for routine care but will for surgery with or without GA (see below).
■ The steroid dose for mild to moderately stressful procedures should be doubled on the day of surgery. For more stressful procedures in patients at high risk, pred- nisolone 60mg should be given on the day of surgery and reduced rapidly over the following three days to the patient ’ s usual dose.
Protocol for managing patients who have stopped taking steroids in the recent past:
■ < 3 months: treat as if on steroids ■ > 3 months: no peri - operative steroids.
Patients on high dose immunosuppression are advised to take their usual doses during the peri - operative period (e.g. 60mg prednisolone daily needs 250mg hydrocortisone infusion during the peri - operative period).
Adrenal m edulla
Epinephrine and norepinephrine are produced in the adrenal medulla. Epinephrine is the hormone responsible for the fi ght or fl ight response mechanism that is triggered in stressful situations. It increases heart rate, alertness and levels of glucose and fat in the blood, etc.
The most likely, but unusual, disorder of the medulla is hypertension as a consequence of a tumour (phaeochromocytoma).
Pancreas – i slets of Langerhans Diabetes m ellitus
This is the most common endocrine disorder of childhood, and may have a genetic, viral or autoimmune cause. The islets of Langerhans cells within the pancreas secrete insulin , which is responsive to levels of glucose in the blood. As well as regulating the concentra- tion of glucose in the blood it also increases the rate of synthesis of fat, glycogen and proteins.
Four types of diabetes mellitus have been described. Type 1 or insulin - dependent diabetes mellitus (IDDM), formerly called juvenile onset, accounts for about 10% of all diabetic patients. It affects two people for every thousand of the population. These patients produce little or no insulin and have a greater tendency to develop ketoacidosis (excess ketone bodies – formed when fatty acids are broken down in the liver as an energy source – in people unable to metabolise glucose). Early in the disease, some patients may not need insulin.
Patients who are controlled by diet alone can be managed as normal patients. Those who are being treated with oral hypoglycaemic drugs (to stimulate residual insulin secre- tion) should not take their normal drugs on the day of any planned surgery but should restart their drugs the following day. Where diabetic control is poor, these patients should be hospitalised for stabilisation before dental surgery.
Antibiotics are not indicated for diabetic patients as there is little evidence to support their use except that response to infection is poor and may complicate diabetic management.
Type II or non - insulin - dependent (formerly called adult onset) is the most common form and accounts for 90% of all diabetes. This is the non - ketosis - prone form of diabetes
where there are decreased amounts of insulin or insulin with decreased activity. A third of type II patients are treated by weight loss, a third by diet and antidiabetic drugs, and the remainder need insulin.
These patients should be admitted to hospital for management of their diabetes during dental surgery.
Type III diabetes is induced by drugs, hormones and genetic syndromes as well as