11 Medicine relevant to dentistry

Chapter 11

Medicine relevant to dentistry

Laura Mitchell

David A. Mitchell

Lorna McCaul

Contents

Medical theory

Emergencies

In-patients


Principal sources C. Scully 2005 Medical Problems in Dentistry, Wright (5th edn). M. Longmore et al. 2007 Oxford Handbook of Clinical Medicine, OUP. D. Mitchell 2006 An Introduction to Oral and Maxillofacial Surgery, OUP. M. Lubin et al. 2006 Medical Management of the Surgical Patient, Cambridge University Press (comprehensive but entirely North American perspective). Various 1995 Procedures in Practice, BMJ. BNF 54.



NB All drug doses relate to fit, adult patients ≅70kg in weight. Always check doses for children, the elderly, and those with other medical conditions.


Anaemia

Anaemia is a ↓ in the level of circulating haemoglobin to below the normal reference range for a patient’s age and sex. It indicates an underlying problem and, as such, the cause of the anaemia should be diagnosed before instituting Rx.

image Never rush into transfusing patients presenting with a chronic anaemia. Perform basic blood investigations before giving iron or transfusing. Elective surgery in patients with an Hb <10g/dl is rarely appropriate.

Clinical features

of anaemia are notoriously unreliable, but beloved of examiners and include: general fatigue, heart failure, angina on effort, pallor (look at conjunctivae and palmar creases, but unreliable), brittle nails &/or spoon-shaped nails (koilonychia), oral discomfort &/or ulceration, glossitis, and classically angular cheilitis.

Syndromes

, p. 730.

Types of anaemia

Microcytic

(MCV < 78fl) Iron-deficiency anaemia is by far the commonest cause. Causes: chronic blood loss (gastrointestinal or menstrual), inadequate diet. FBC and biochemistry show microcytic, hypochromic anaemia with a low serum iron and a high total iron binding capacity (TIBC). ↑ RBC zinc protoporphyrin is a fast and sensitive early test. Thalassaemia and sideroblastic anaemia are rare causes of microcytosis.

Normocytic

Commonly, anaemia of chronic disease. Other causes: pregnancy, acute blood loss, haemolytic anaemia, and aplastic anaemia. Once pregnancy is excluded, the patient needs investigation by an expert. The TIBC is usually ↓.

Macrocytic

(MCV > 100fl) Low B12 &/or low folate are the common causes. B12 is ↓ in pernicious anaemia (deficit of intrinsic factor), alcohol abuse, small gut disease, and chronic exposure to nitrous oxide. Low folate is usually dietary, but may be caused by illness (e.g. coeliac disease, skin disease) or drugs such as phenytoin, methotrexate, trimethoprim, and co-trimoxazole.

Management

In all cases the cause must be sought; this may necessitate referral to a haematologist. Drugs used in iron deficiency: ferrous sulfate 200mg tds. Transfusion of packed cells covered with furosemide 40mg PO if elderly or ↓ cardiac function, indicated rarely for severe microcytic anaemia. Lifelong IM hydroxocobalamin 1mg 3-monthly is used to treat B12 deficiency, and folic acid 5mg od for folate deficiency.

image Never use folate alone to treat ‘macrocytosis’ unless it is proven to be the only deficiency. NB Folic acid is not the same as folinic acid.

Note on sickle cell anaemia

A homozygous hereditary condition causing red cells to ‘sickle’ when exposed to low O2 tensions, resulting in infarctions of bone and brain. In sickle cell trait (heterozygous form) the cells are less fragile and sickle only in severe hypoxia. Management: perform haemoglobin electrophoresis (or Sickledex if result needed urgently) on all Afro-Caribbean (and consider Mediterranean, Middle Eastern, and Indian) patients planned for GA.

Haematological malignancy

Leukaemias

are a neoplastic proliferation of white blood cells. Acute leukaemias are characterized by the release of primitive blast cells into the peripheral blood and account for 50% of childhood malignancy. Acute lymphoblastic leukaemia, the commonest childhood leukaemia, now has up to 90% cure rate in favourable cases. May present as gingival hypertrophy and bleeding. Acute myeloblastic leukaemia is the commonest acute leukaemia of adults, but although an 80% remission rate is possible this is rarely maintained. Chronic leukaemias have cells that retain most of the appearance of normal white cells. Chronic lymphocytic leukaemia is the commonest and has a 5-yr survival of >50%. Chronic myeloid leukaemia is characterized by the presence of the Philadelphia chromosome, a fact beloved by examiners. Affects the >40s. Rx: interferon &/or bone marrow transplant (BMT) or stem cell transplantation. Remissions are common, although a terminal blast crisis usually supervenes at some stage.

Myeloproliferative disorders

are proliferation of non-leukocyte marrow cells, with a wide range of behaviour and presentation, including anaemia, bleeding, and infections.

Monoclonal gammopathies such as multiple myeloma are B-lymphocyte disorders characterized by production of a specific immunoglobulin by plasma cells. Multiple myeloma is also a differential ∆ of lytic lesions of bone, particularly the skull. ∆: monoclonal paraprotein band on plasma electrophoresis, Bence–Jones proteins in urine.

Lymphomas

A group of solid tumours arising in lymphoid tissue; divided into Hodgkin’s or non-Hodgkin’s lymphomas, with the latter carrying a poorer prognosis. Lymphoma should always be considered in the differential ∆ of neck swellings.

Cytotoxic chemotherapy

Has been the mainstay of Rx for these diseases, with supplemental radiotherapy for masses or prior to BMT. It is essential to remember that any patient receiving these drugs will be both immunocompromised and liable to bleed.

Hints

In haematological malignancy, anaemia, bleeding, and infection are the overwhelming risks. Look for and treat anaemia. Avoid aspirin, other NSAIDs, trauma, and IM injections. Prevent sepsis, and if it occurs treat very aggressively with the locally recommended broad-spectrum antibacterials and antifungals, e.g. piperacillin/tazobactam 2.25g and gentamicin 80mg IV tds plus fluconazole up to 100mg daily. Liaise with haematologist urgently.

Amyloidosis

Characterized by deposits of fibrillar eosinophilic hyaline material in a wide range of organs and tissues. Two types: 1° amyloidosis (AL amyloid), a plasma cell dyscrasia. Signs and symptoms include peripheral neuropathy, renal involvement, cardiomyopathy, xerostomia, and macroglossia. Rx: immunosuppression (rarely helps). 2° amyloidosis (AA amyloid). It reflects an underlying chronic disease: infection, rheumatoid, neoplasia. May respond to Rx of underlying disease. ∆: biopsy of rectum or gingivae—stain with Congo red.

Other haematological disorders

For the practical management of a bleeding patient, see p. 348.

Bleeding disorders

Platelet disorders

May present as nosebleeds, purpura, or post-extraction bleeding. Remember that aspirin is the most common acquired cause, its effect being irreversible for 1 week. Other causes include diseases such as Von Willebrand’s disease; immune thrombocytopenic purpura (ITP); virally associated (especially HIV) thrombocytopenic purpura; thrombocytopenia secondary to leukaemia; cytotoxic drugs; or unwanted effects of drugs, notably aspirin and chloramphenicol. Management: ensure platelet levels of >50 × 109/l, preferably 75 × 109/l for anything more than simple extraction or LA. If actively bleeding, use a combination of local measures (p. 348), tranexamic acid, and platelet transfusion. Platelet transfusions are short-lived and if used prophylactically must be given immediately prior to or during surgery. Liaise closely with the lab. The quality of preparation varies by locality. Tranexamic acid mouthwash may ↓ oral bleeding.

Coagulation defects

Present as prolonged wound bleeding &/or haemarthroses. Causes include the haemophilias, anticoagulants, liver disease, and von Willebrand’s disease.

Others

Less common causes include: hereditary haemorrhagic telangectasia, aplastic anaemia, chronic renal failure, myeloma, SLE, disseminated intravascular coagulation, and isolated deficiency of clotting factors.

Haemophilia A (factor VIII deficiency)

The commonest clotting defect. Inherited as a sex-linked recessive, it affects males predominantly, although female haemophiliacs can occur. All daughters of affected males are potential carriers. Usually presents in childhood as haemarthroses. Bleeding from the mouth is common. Following trauma, bleeding appears to stop, but an intractable general ooze starts after an hour or so. Severity of bleeding is dependent on the level of factor VIII activity and degree of trauma.

Haemophilia B (factor IX deficiency)

Clinically identical to haemophilia A; also known as Christmas disease.

Von Willebrand’s disease

A combined platelet and factor VIII disorder affecting males and females. Mucosal purpurae are common, haemarthroses less so. Wide range of severity. May improve with age &/or pregnancy.

Management

The haemophilias and Von Willebrand’s disease should always be managed at specialist centres. Check the patient’s warning card for the contact telephone number.

Anticoagulants

Heparin

Given IV or high-dose SC for therapeutic anticoagulation. Its effect wears off in ~8h although it can be reversed by protamine sulfate in an emergency. Measure in activated partial thromboplastin time (APTT).

Warfarin

Given orally; effects take 48h to be seen. Normal therapeutic range is an International Normalized Ratio (INR) of 2–4. Simple extractions are usually safe at a level within therapeutic range. Reverse the effects of warfarin with vitamin K +/or fresh frozen plasma if needed, but consider why the patient is anticoagulated in the first place. See p. 548.

Cardiovascular disease

This is the commonest cause of death in the UK.

Clinical conditions

Hypertension

is a consistently raised BP (>140 systolic, >90 diastolic >3 months) and is a risk factor for ischaemic heart disease, cerebrovascular accidents, and renal failure. Up to 95% of hypertension has no definable cause: essential hypertension. 5% is secondary to another disease such as renal dysfunction or endocrine disorders.

Ischaemic heart disease

is ↓ of the blood supply to part of the heart by narrowing of the coronary arteries, usually by atheroma, causing the pain of angina pectoris. If occluded, an MI occurs (p. 522).

Heart failure

is the end result of a variety of conditions, not all of them cardiovascular. Basically, the heart is unable to meet the circulatory needs of the body. In right heart failure, dependent oedema and venous engorgement are prominent. In left heart failure, breathlessness is the principal sign. The two often coexist. There is an ever-present risk of precipitating heart failure, even in treated patients, by ↑ the demands on the heart, e.g. by fluid overload or excessive exertion.

Hypovolaemic shock

is collapse of the peripheral circulation due to a sudden ↓ in the circulating volume. If this is not corrected there can be failure of perfusion of the vital organs, resulting in heart failure, renal failure, and unconsciousness ending in death.

Murmurs

are disturbances of blood flow which are audible through a stethoscope. They may be functional or signify structural disorders of the heart. Echocardiography will differentiate. They are of great relevance to dentists as their presence warns of the potential for colonization of damaged valves by blood-borne bacteria. Such a bacteraemia can be caused by dental procedures.

Dental implications

Patients with a PMH of rheumatic fever are very likely to have some damage to a heart valve, usually the mitral valve. Traditionally advice has been to provide antibiotic prophylaxis for invasive dental procedures, but recent guidance has advised against this.1 The risk of precipitating heart failure or MI in patients with compromised cardiovascular systems is ever-present. Prevent by avoiding GA, especially within 3 months of an MI, using adequate LA with sedation if necessary, and avoid excessive adrenaline loads. Consider potential drug interactions (p. 578) and remember some of these patients will be anticoagulated.

Exclusion of septic foci may be requested in patients at high risk from bacteraemia, e.g. heart transplant recipients, those with prosthetic valves or valvular damage, or those with a history of IE. It is prudent to err on the side of caution with these individuals and some will need dental clearances.

Respiratory disease

Disease of the chest is an everyday problem in developed countries. The principal symptoms are cough, which may or may not be productive of sputum, dyspnoea (breathlessness), and wheeze. The coughing of blood (haemoptysis) mandates that malignancy be excluded.

Clinical conditions

Upper respiratory tract infections

Include the common cold, sinusitis, and pharyngitis/tonsillitis (which may be viral or bacterial), laryngotracheitis, and acute epiglottitis. All are C/I to elective GA in the acute phase. Sinusitis (p. 384). Penicillin is the drug of choice for a streptococcal sore throat. Avoid amoxicillin and ampicillin, as glandular fever may mimic this condition and these drugs will produce a rash, of varying severity, in such a patient. Epiglottitis is an emergency, and the larynx should NEVER be examined unless expert facilities for emergency intubation are to hand.

Lower respiratory tract infections

Both viral and bacterial lower tract infections are debilitating and constitute a C/I to GA for elective surgery. Bear in mind TB and atypical bacteria, e.g. legionella, mycoplasma, and coxiella. Open TB is highly infectious and cross-infection precautions are mandatory (p. 718).

Chronic obstructive pulmonary disease (COPD)

A very common condition usually caused by a combination of bronchitis (excessive mucus production, persistent productive cough >3 months per year for 3yrs) and emphysema (dilation and destruction of air spaces distal to the terminal bronchioles). Smoking is the prime cause and must be stopped for Rx to be of any value. Be aware of possible systemic steroid use.

Asthma

Reversible bronchoconstriction causes wheezing and dyspnoea. Up to 8% of the population are affected; there is often an allergic component. Patients complain of the chest feeling tight. May be precipitated by NSAIDs. Penicillin and aspirin allergies are more common. Management of acute asthma, p. 533.

Cystic fibrosis

An inherited disorder whereby viscosity of mucus is ↑. Patients suffer pancreatic exocrine insufficiency and recurrent chest infections. ∆: by history and sweat sodium measurement.

Bronchial carcinoma

Causes 27% of cancer deaths. Principal cause is smoking. ↓ incidence in females. Symptoms are persistent cough, haemoptysis, and recurrent infections. 2-yr survival is only 10%. Mesothelioma is an industrial disease caused by asbestos exposure.

Sarcoidosis

Most commonly presents as hilar lymphadenopathy in young adults. Oral lesions can occur. Erythema nodosum common.

Dental implications

Avoid GA. Use analgesics and sedatives with caution; opioids and sedatives ↓ respiratory drive, NSAIDs may exacerbate asthma. Advise your patients to stop smoking (and if you are a smoker, stop). Refer if suspicious, especially in the presence of confirmed haemoptysis.

Gastrointestinal disease

The mouth and its mucosal disorders and disorders of the salivary glands are covered in Chapter 9.

Oesophagus

Presents symptoms which can be confused with those originating from the mouth, the most important being dysphagia. Difficulty in swallowing may be caused by conditions within the mouth (e.g. ulceration), pharynx (e.g. FB), benign or malignant conditions within oesophagus, compression by surrounding structures (e.g. mediastinal lymph nodes), or neurological causes. It is a symptom which should be taken seriously and investigated by at least CXR, barium swallow, &/or endoscopy. Reflux oesophagitis is a common cause of dyspepsia, sore throat, cough, and bad taste.

Peptic ulceration and gastric carcinoma

(duodenal malignancy rare) May present with epigastric pain, vomiting, haematemesis, or melaena.

Peptic ulceration

Commonly due to infection with Helicobacter pylori and usually responds to H. pylori eradication therapy (combination of proton pump inhibitor/broad spectrum antibiotic/anaerobicidal, i.e. metronidazole). Other causes include stress ulceration in critically ill or major surgical patients, and elderly people on NSAIDs. Prophylaxis with sucralfate, a mucosal protectant, is more appropriate than H2 antagonists as the gastric pH barrier is maintained but is a problem practically as it clogs fine bore NGT. Symptomatic relief of dyspepsia without significant ulceration is with antacids and alginates. Persisting epigastric pain or other symptoms must be investigated as gastric carcinoma requires early surgery and carries a poor prognosis. ► Endoscopic investigation of patients >40 with persisting epigastric symptoms is mandatory.

Non-malignant, Helicobacter-negative ulceration (oesophagitis, gastritis, duodenitis) clears with 1 month of proton pump inhibitor Rx (e.g. omeprazole 10–20mg od) and can often be maintained with H2 antagonists (ranitidine or cimetidine).

Small bowel

This has a multitude of associated disorders which tend to present in a similar manner; namely, malabsorption syndromes, diarrhoea, steatorrhoea, abdominal pain, anaemia, and chronic deficiencies. Coeliac disease and Crohn’s disease are the best known conditions. Coeliac disease is a hypersensitivity response of the small bowel to gluten and treated by strict avoidance. A number of oral complaints are related, typically ‘cobblestoning’ of the mucosa. Crohn’s disease may affect any part of the gastrointestinal tract but has a preference for the ileo-caecal area. It is a chronic granulomatous disease affecting the full thickness of the mucosa and may result in fistula formation. Ulcerative colitis is often mistaken for Crohn’s disease initially, but affects the colorectum only. Treatment with systemic steroids and other immunosuppresants is common.

Large bowel

Diverticular disease is a condition with multiple outpouching of large bowel mucosa which can become inflamed, causing diverticulitis. The irritable bowel syndrome is a condition associated with ↑ colonic tone, causing recurrent abdominal pain; there may be some psychogenic overlay.

Colonic cancer is common in older patients; it may present as rectal bleeding, a change in bowel habit, intestinal obstruction, tenesmus (wanting to defecate but producing nothing), abdominal pain, or anaemia. It is treated surgically, with up to 90% 5-yr survival if diagnosed early (Duke’s A). Familial polyposis coli is associated with the Gardener syndrome (p. 728). Antibiotic-induced colitis results from overgrowth of toxigenic Clostridium difficile after use of antibiotics, commonly ampicillin and clindamycin. It responds to oral vancomycin or metronidazole.

The pancreas

Malignancy has the worst prognosis of any cancer and most Rx is essentially palliative.

Acute pancreatitis

Often a manifestation of alcohol abuse. Aetiology is not entirely clear. Causes acute abdominal pain. Amylase levels are a guide but not infallible. Patients need aggressive rehydration, maintenance of electrolyte balance, and analgesia, in high-dependency or ICU setting.

Hepatic disease

The main problems presented by patients with liver disease are: the potential for increased bleeding, inability to metabolize and excrete many commonly used drugs, and the possibility that they can transmit hepatitis B, C &/or D (Hep A and E are spread by faecal–oral route). The liver is also a site of metastatic spread of malignant tumours. Patients in liver failure needing surgery, especially under GA, are a high-risk group who should have specialist advice on their management.

Jaundice

The prime symptom of liver disease. It is a widespread yellow discoloration of the skin (best seen in good light, in the sclera), caused by the inability of the liver to process bilirubin, the breakdown product of haemoglobin. This occurs either because it is presented with an overwhelming amount of bilirubin to conjugate (e.g. haemolytic anaemia), or it is unable to excrete bile (cholestatic jaundice). Cholestatic jaundice in turn may be either intrahepatic or extrahepatic.

Intrahepatic cholestasis

represents hepatocyte damage; this is reflected by ↑ aspartate transaminase levels on liver function tests, and results in impaired bile excretion, as indicated by ↑ plasma bilirubin. Causes include alcohol and other drugs, toxins, bacterial and viral infections. A degree of hepatitis is present with these causes, whereas primary biliary cirrhosis and anabolic steroids cause a specific intrahepatic cholestasis without hepatitis.

Extrahepatic cholestasis

is caused by obstruction to the excretion of bile in the common bile duct by gallstones, tumour, clot, or stricture. Carcinoma of the head of the pancreas, or adjacent lymph nodes, may also compress the duct, and must be excluded.

Surgery in patients with liver disease

Ascertain a ∆ for the cause. Do hepatitis serology. Cross-infection precautions (p. 718).
Do coagulation screen. May need correction with vitamin K or fresh-frozen plasma.
Always warn the anaesthetist, as it will affect the choice of anaesthetic agents.
If a jaundiced patient must undergo surgery correct fluid and electrolyte balance, and ensure a good peri-operative urine output by aggressive IV hydration with 5% dextrose and mannitol diuresis to avoid hepato-renal syndrome (see OHCM).
Do not use IV saline in patients in fulminant hepatic failure, as there is a high risk of inducing encephalopathy.

Liver disease patients in dental practice

Know which disease you are dealing with. If Hep B or C employ strict cross-infection control (p.718).
Be cautious in prescribing drugs (consult the BNF/DPF) and with administering LA.
Do not administer GAs.
Take additional local precautions against post-op bleeding following simple extractions (p. 348). A clotting screen should be obtained for anything more advanced, and in all patients with severe liver disease.

Renal disorders

The commonest urinary tract problems, infections, are of relevance only to those who manage in-patients. Rarer conditions such as renal failure and transplantation are, surprisingly, of more general relevance because these patients are at ↑ risk from infection, bleeding, and iatrogenic drug overdose during routine Rx.

Urine

This is tested in all in-patients. ‘Multistix’ will test for glycosuria (diabetes, pregnancy, infection), proteinuria (diabetes, infection, nephrotic syndrome), ketones (diabetic ketoacidosis), haematuria (infection, tumour), and bile as bilirubin and urobilinogen (cholestatic jaundice).

Urinary tract infections

A common cause of toxic confusion in elderly in-patients, especially females. Send a mid-stream urine (MSU) for culture and sensitivity, then start trimethoprim 200mg bd PO or ampicillin 250mg qds PO and ensure a high fluid intake. Minimal investigations of renal function are U&Es, creatinine, and ionized Ca2+.

Nephrotic syndrome

A syndrome of proteinuria (>3.6g/day), hypoalbuminaemia, and generalized oedema. Facial oedema is often prominent. Glomerulonephritis is the major precipitating cause and investigations should be carried out by a physician with an interest in renal medicine.

Acute renal failure (ARF)

A medical emergency causing a rapid rise in serum creatinine, urea and K+. It may follow surgery or major trauma and is usually marked by a failure to PU. Remember the commonest causes of failing to PU post-op are under-infusion of fluids and urinary retention. Rx: ↑ IV fluid input and catheterize (p. 543). If ARF is suspected get urgent U&Es, ECG, and blood gases. Obtain aid from a physician. Control of hyperkalaemia, fluid balance, acidosis, and hypertension are the immediate necessities.

Chronic renal failure

Basically the onset of uraemia after gradual, but progressive renal damage, commonly caused by glomerulonephritis (inflammation of the glomeruli following immune complex deposits), pyelonephritis (small scarred kidneys due to childhood infection, irradiation, or poisoning), or adult polycystic disease (congenital cysts within Bowman’s capsule). It has protean manifestations, starting with nocturia and anorexia, progressing through hypertension and anaemia to multi-system failure. Continuous ambulatory peritoneal dialysis, haemodialysis, and transplants are the mainstays of Rx.

Main problems relevant to dentistry

↑ risk of infection, worsened by immunosuppression.
↑ bleeding tendency.
↓ ability to excrete drugs.
Veins are sacrosanct; never use their A-V fistula.
Bone lesions of the jaws (renal osteodystophy, 2° hyperparathyroidism).
Generalized growth impairment in children.
Potential carriage of Hep B, HIV.

Renal transplantation

An increasingly common final Rx of renal failure, and when successful renal function may reach near normal levels. Kidneys are, however, immunosuppressed and at greatly ↑ risk from infection. They may share the problems associated with chronic renal failure depending on the level of function of the transplant.

Hints

Take precautions against cross-infection (p. 718).
Treat all infections aggressively and consider prophylaxis.
Use additional haemostatic measures (p. 348).
Be cautious with prescribing drugs (p. 558).
Never subject these patients to out-patient GA.
Remember veins are precious.
Try to perform Rx just after dialysis if possible.

Endocrine disease

Addison’s disease

1° hypoadrenocorticism. Atrophy of the adrenal cortices causes failure of cortisol and aldosterone secretion. 2° hypoadrenocorticism is far commoner, due to steroid therapy or ACTH deficiency (p. 552). All need steroid cover.

Conn’s syndrome

Primary hyperaldosteronism causes hypokalaemia and hypernatraemia with hypertension.

Cushing’s disease and Cushing syndrome

These are due to excess corticosteroid production. The disease refers to 2° adrenal hyperplasia due to ↑ ACTH, whereas the syndrome is a 1° condition, usually due to therapeutic administration of synthetic steroid or adenoma. Classical features are obesity (moon face, buffalo hump) sparing the limbs, osteoporosis, skin thinning, and hypertension.

Diabetes insipidus

Production of copious dilute urine due to ↓ ADH secretion or renal insensitivity to ADH. May occur temporarily after head injury.

Diabetes mellitus

Persistent hyperglycaemia due to a relative deficiency of insulin (p. 550).

Gigantism/acromegaly

Excess production of growth hormone, before and after fusion of the epiphyses, respectively.

Goitre

A large thyroid gland, of whatever cause.

Hyperthyroidism

Symptoms of heat intolerance, weight loss, and sweating occur. Signs are tachycardia (may have atrial fibrillation), lid lag, exopthalmos, and tremor. Commonest cause is Graves’ disease (p. 728). Functioning adenomas are another cause.

Hypothyroidism

Can be 1° due to thyroid disease, or 2° to hypothalamic or pituitary dysfunction. 1° disease is often an autoimmune condition. Symptoms are poor tolerance of cold, loss of hair, weight gain, loss of appetite, and poor memory. Signs are bradycardia and a hoarse voice.

Hyperparathyroidism

1° is caused by an adenoma. 2° is a response to low plasma Ca2+, e.g. in renal failure, and 3° follows on from 2° when the parathyroids continue ↑ production, even if Ca2+ is normalized.

Hypoparathyroidism

Usually 2° to thyroidectomy, when parathyroid glands inadvertently removed. Plasma Ca2+ ↓, resulting in tetany. Chvosteck’s sign is +ve if spasm of facial muscles occurs after tapping over the facial nerve.

Hypopituitarism

Can lead to 2° hypothyroidism or 2° hypoadrenocorticism.

Inappropriate ADH secretion

Caused by certain tumours (e.g. bronchial carcinoma), head injury, and some drugs. Hyponatraemia, overhydration, and confusion occur.

Lingual thyroid

May be the only functioning thyroid the patient has; do not excise lightly. Do pre-op isotope scan.

Phaeochromocytoma

A very rare tumour of the adrenal medulla, secreting adrenaline and noradrenaline. Symptoms are recurring palpitations and headache with sweating. Simultaneous hypertension with a return to baseline on settling of symptoms, is a good marker.

Pituitary tumours

May erode the pituitary fossa (seen on lateral skull X-ray) and can cause blindness via optic chiasma compression.

Endocrine-related problems

image Always ask yourself ‘Is she, or can she be, pregnant?’

Pregnancy

is a C/I to elective GA, the vast majority of drugs (p. 558), and non-essential radiography (the most vulnerable period being in the first 3 months). Elective Rx is best performed in the mid-trimester.

Menopause

The end of a woman’s reproductive life and her periods. It is often associated with hot flushes and other relatively minor physical problems. Emotional disturbances may coexist, and the incidence of psychiatric disorders increases at this time.

Related problems

Suxamethonium sensitivity

Around 1:3000 people have an inherited defect of plasma cholinesterase. These families are absolutely normal in every respect except in their ability to metabolize suxamethonium. This leaves them unable to destroy the drug which, normally wearing off in 2–4min, produces prolonged muscle paralysis. This paralysis requires ventilatory support until the drug wears off, which, in the homozygote, may take as long as 24h.

Malignant hyperpyrexia

A rare, potentially lethal reaction to, usually, an anaesthetic agent. Characterized by ↑ pulse, muscle rigidity, and ↑ temperature. Dantrolene sodium and cooling may be life-saving.

Rare endocrine tumours

Glucagonoma

Secretes glucagon causing hyperglycaemia.

Insulinomas

Secrete insulin. Causes sporadic hypoglycaemic episodes.

Gastrinomas

Secrete gastrin causing duodenal ulcers and diarrhoea (Zollinger–Ellison syndrome).

Multiple endocrine neoplasia (MEN) syndromes

A rare group of endocrine tumours. MEN IIb is medullary thyroid cancer, phaeochromocytoma, and oral mucosal neuromas.

Bone disease

Pathology of the bones of the facial skeleton is covered in Chapter 8.

Osteogenesis imperfecta

(brittle bone disease) An autosomal dominant type 1 collagen defect. Multiple # following slight trauma with rapid but distorted healing is characteristic. Associated with blue sclera, deafness, and dentinogenesis imperfecta (p. 67). The jaws are not particularly prone to # following extractions.

Osteopetrosis

(marble bone disease) There is an ↑ in bone density and brittleness, and a ↓ in blood supply. Prone to infection which is difficult to eradicate. Bone pain, #, and compression neuropathies may occur. Anaemia can complicate severe disease. Facial characteristics are frontal bossing and hypertelorism.

Achondroplasia

An inherited defect in cartilaginous bone formation, usually autosomal dominant. Causes a ‘circus dwarf’ appearance with skull bossing; many have no other problems.

Cleidocranial dysostosis

An inherited defect of membranous bone formation, usually autosomal dominant. Skull and clavicles are affected. Multiple unerupted teeth with retention of 1° dentition is characteristic.

Disorders of bone metabolism

Rickets/osteomalacia

Failure of bone mineralization in, respectively, children and adults. Can be caused by deficiency, failure of synthesis, malabsorption, or impaired metabolism of Vitamin D, and also hypophosphataemia or ↑ Ca2+ requirement in pregnancy.

Osteoporosis

A lack of both bone matrix and mineralization. Important causes are steroid therapy, post-menopausal hormone changes, immobilization, and endocrine abnormalities. HRT in post-menopausal women appears helpful. Results in ↑ incidence of #, especially femoral neck and wrist. Bisphosphonates are being aggressively promoted in the treatment of osteoporosis resulting in some of the noted increase in BRON p. 352.

Fibrous dysplasia

Replacement of a part of a bone or bones by fibrous tissue with associated swelling. It usually starts in childhood and ceases with completion of skeletal growth. Termed monostotic if one bone is affected, polyostotic if more than one bone, and Albright syndrome if associated with precocious puberty and café au lait areas of skin hyperpigmentation.

Cherubism

A bilateral variant of fibrous dysplasia.

Paget’s disease of bone

A common disorder of the elderly, where the normal, orderly replacement of bone is disrupted and replaced by a chaotic structure of new bone, causing enlargement and deformity. The hands and feet are spared. Complications include bone pain and cranial nerve compression, or, more rarely, high output cardiac failure or osteosarcoma. Another condition treated with bisphosphonates.

Diseases of connective tissue, muscle, and joints

Connective tissue diseases

These are mainly vasculitides (inflammation of vessels).

Cranial arteritis (temporal arteritis)

Giant cell vasculitis of the craniofacial region. Presenting symptom is unilateral throbbing headache. Signs are high ESR with a tender, pulseless artery. Major complication of temporal arteritis is optic nerve ischaemia causing blindness, so start high-dose steroids (60mg prednisolone PO od) and monitor using ESR. Biopsy confirms.

Polymyalgia rheumatica

More generalized vasculitis affecting proximal axial muscles. Accounts for 25% of cases of cranial arteritis. Responds to steroids; gradual improvement with time.

Disease of muscles

Muscular dystrophy

A collection of inherited diseases characterized by muscle degeneration. Most are fatal in early adulthood.

Myotonic disorders

Distinguished by delayed muscle relaxation after contraction. They are genetically determined in a complex fashion.

Polymyositis

A generalized immune-mediated inflammatory disorder of muscle. If a characteristic rash is present the condition is known as dermatomyositis and has an association with occult malignancy.

Joint disease

Osteoarthritis

1° degeneration of articular cartilage, cervical and lumbar spine, hip and knee joints, commonly affected or 2° to trauma or other joint disease, resulting in pain and stiffness. Osteophyte formation and subchondral bone cysts, which collapse leading to deformity, are characteristic. Physiotherapy, weight loss, and analgesia are the mainstays of Rx. Joint replacement is definitive Rx.

Rheumatoid arthritis

Immunologically mediated disease where joint pain and damage are the most prominent symptoms. Morning pain and stiffness in the hands and feet, usually symmetrical, is characteristic. There may be systemic upset and anaemia. Ulnar deviation of the fingers is patho-gnomonic. Rx includes NSAIDs, steroids, and physiotherapy. Second line or disease-modifying antirheumatic drugs (DMARDs) may favourably influence outcome at expense of unwanted effects, e.g. penicillamine, antimalarials, immunosuppressants (including TNFα chimeric monoclonal antibody—Infliximab). Dry eyes and mouth may be associated with rheumatoid arthritis (Sjögren syndrome, p. 422). TMJ symptoms are rare in rheumatoid arthritis, although up to 15% of patients have radiographic changes in the joint.

Juvenile rheumatoid arthritis (Still’s disease)

Rarer form of the disease affecting children. It can be much more severe than the adult condition and can cause TMJ ankylosis.

Psoriatic arthritis

Associated with the skin condition and affects the spine and pelvis. It is milder than rheumatoid arthritis and has no serological abnormalities. The TMJ />

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Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 11 Medicine relevant to dentistry
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