Clinical Scenario

An 80‐year‐old male presents for a dental appointment complaining of a 2‐week history of pain from his lower left first molar tooth, which he reports is worse on chewing. The patient had root canal treatment undertaken for this tooth 2 years earlier following similar symptoms.

Structured Learning

1. The patient reports he has been feeling particularly tired over the last 5 days, and thinks he may have had a raised temperature, although this is not always present. Why is this of particular concern?
   • This patient is at risk of infective endocarditis (IE)
   • There is a confirmed dental infection (#36) which could lead to bacteraemia and the development of IE
   • A low‐grade, often intermittent fever is present in up to 90% of patients who develop IE
   • Without treatment, IE may be fatal in approximately 30% of individuals
2. What would you do in response to your concerns?
   • Ensure that you check the patient’s temperature
   • Check for other signs of IE
     • Heart murmurs (85%)
     • One or more classic signs (50%)
       • Petechiae – common but nonspecific finding
         

         

       • Splinter haemorrhages – dark red linear lesions on the nailbeds
       • Osler nodes – tender subcutaneous nodules on the distal pads of the digits
       • Janeway lesions – non‐tender maculae on the palms and soles
       • Roth spots – retinal haemorrhages with small, clear centres
       • Signs of embolic phenomena
       • Haematuria
       • Cerebrovascular occlusion

     • Signs of congestive heart failure
     • Signs of immune complex formation such as vasculitis, arthritis and renal damage
   • Contact the cardiologist for urgent review and further investigations (e.g. ECG, echocardiography, blood culture); explain that there is evidence of an infected tooth
     

     

   • Antibiotics should be prescribed in close liaison with the cardiologist (the patient may receive these from the cardiologist or intravenously if admitted to hospital)
3. The patient is seen by the cardiologist who confirms that the patient does not have any evidence of IE but asks you to remove any source of oral infection urgently. What factors are considered important in assessing the risk of managing this patient?
   • Social
     • Frail – requires an escort who can bring him to the appointment and also look after him on discharge
   • Medical
     • Dental treatment can trigger the onset of prosthetic valves IE
     • Risk of a hypertensive crisis during dental treatment and orthostatic hypotension (see Chapter 8.1)
     • Tendency to bleed due to the acenocoumarol (see Chapter 10.3), arterial hypertension (see Chapter 8.1) and/or digoxin‐induced thrombocytopenia
     • Drug interactions mainly with acenocoumarol, digoxin and/or antihypertensive agents
   • Dental
     • The dental treatment proposed is to extract #36 – this is an invasive procedure associated with a higher risk of bacteraemia/bleeding
     • History of irregular dental attendance ‐ the patient may be lost to follow‐up
4. Before the appointment for the surgical treatment, you request an INR (international normalised ratio) test as the patient is taking acenocoumarol daily. The test is undertaken the day before the procedure and the result reported as 1.8. What would be your approach?
   • From the dental viewpoint, clinically significant increased bleeding is not expected (see Chapter 10.3) and the surgical procedure can proceed
   • However, the patient is considered at high thromboembolic risk, because he has a mechanical mitral prosthesis and an aortic prosthesis, with additional risk due to atrial fibrillation; accordingly, the recommendation is a target INR of 3.0 (range 2.5–3.5)
   • The patient should be referred to his anticoagulation clinic/physician for adjustment of the anticoagulant therapy
5. When prescribing antibiotics for bacterial endocarditis prophylaxis, what factors should you consider for this patient?
   • Courses of amoxicillin, azithromycin and clarithromycin increase the bleeding tendency in patients receiving acenocoumarol, although this has not been confirmed following a single antibiotic dose
   • Clarithromycin interacts with digoxin, increasing its concentration
   • Clindamycin does not interact with acenocoumarol or digoxin
   • Although in general no specific modifications in the pharmacotherapy of antibiotics are needed for the healthy geriatric patient, this patient is frail with multiple comorbidities and should be advised to report any side‐effects as soon as possible
     • Gastrointestinal symptoms such as pseudomembranous colitis are an important complication of antibiotic therapy in the elderly; although many antibiotics may be implicated, certain drugs such as clindamycin, broad‐spectrum penicillins and second‐ and third‐generation cephalosporins are most often reported to trigger symptoms
     • Increased susceptibility to adverse drug reactions and drug interactions associated with antimicrobial therapy (e.g. age‐related physiological decline in kidney function, coupled with the severe renal effects associated with congestive heart failure and hypertension, substantially influences the excretion of several antibiotics)
6. The patient copes well with dental extraction of #36 with no signs of anxiety. However, when you raise the dental chair to the upright position the patient starts to faint. What could be the cause and what would you do?
   • The faintness could be linked to an episode of drug‐induced orthostatic hypotension – the patient is taking furosemide (diuretic) and bisoprolol (beta‐blocker)
   • Appropriate action includes:
     • Laying the patient back in the chair in the supine position until the symptoms subside
     • Determine the blood pressure with the patient lying down
     • Raise the chair up slowly in stages
     • Retake the blood pressure during the first 3 minutes standing; in most cases, there will be a reduction in systolic blood pressure  ≥20 mmHg and/or a reduction in diastolic blood pressure ≥10 mmHg
     • If 2 episodes on different weeks are recorded, the recommendation is to consult the physician
7. What can you do to prevent a further episode of orthostatic hypotension during subsequent dental treatment sessions?
   • Avoid scheduling appointments for postprandial periods, especially those after large meals
   • The dental chair’s backrest should not be inclined more than 45°
   • Perform changes in position in gradual stages
   • Cross the legs to increase the tolerance to orthostatism (standing up)
8. What should be the first choice for an analgesic for this patient?
   • Paracetamol at dosages that do not exceed 2 g/day is recommended
   • Non‐steroidal anti‐inflammatory drugs can impair the antihypertensive effect of beta‐adrenergic blockers (bisoprolol) and diuretics (furosemide and spironolactone)
   • Some non‐steroidal anti‐inflammatory drugs increase the risk of bleeding by interacting with acenocoumarol, and some can increase the risk of digoxin poisoning
   • Selective anti‐inflammatory cyclo‐oxygenase‐2 inhibitors (e.g. rofecoxib and celecoxib) can boost the action of acenocoumarol and are contraindicated for patients with heart problems

General Dental Considerations