Clinical Scenario

A 67‐year‐old male presents to your dental clinic complaining of ‘weak’ and ‘crumbling’ teeth. He feels that his teeth have been progressively breaking down over the last 5 years.

Structured Learning

1. What risk factors does this patient have for the development of COPD?
   • Tobacco consumption: 75 pack‐years in total; 1 pack‐year is calculated as smoking 20 cigarettes, or 1 pack, every day for 1 year (or equivalent); a higher pack‐year is associated with a higher risk of lung cancer and reduced survival
     

     

   • Occupation: exposure to cooking fumes from either the use of fossil fuels or liquefied petroleum gas (Figure 9.1.2)
   • Low BMI and malnutrition in COPD have been linked with a poor prognosis
   • The patient is from a lower socioeconomic group
     

     

2. What factors could be contributing to this patient’s high level of dental caries?
   • Poor oral hygiene
   • Not using fluoride toothpaste
   • Irregular dental attender
   • Inhaled drug therapy:
     • Inhaled beta‐2‐agonists may lead to reduced salivary flow due to the effect of these medications on the receptors in the parotid and other salivary glands
     • This reduction has been associated with a concomitant reduction in pH, increased food retention and increase in cariogenic bacterial load (e.g. Streptococcus mutans)
     • Dry powder inhalers also contain fermentable carbohydrates, the most common of which is lactose monohydrate
   • Some studies have found a correlation between tobacco smoking and an increased risk of dental caries
3. Prior to planning the delivery of dental treatment, what additional questions would you ask the patient to assess the severity of his COPD?
   • Is he seen by a specialist in hospital or by his local doctor?
   • How often should he be reviewed (given his limited financial means, this may not be the same as how often he attends)?
   • What triggers a worsening of his symptoms of COPD/breathlessness (e.g. walking, exercise)?
   • Does he take his medications regularly?
   • How often does he need to use his relieving inhalers?
   • How long has he been taking prednisolone and at what dose?
   • Have there been any hospital admissions related to his COPD? If so when/how often?
4. The patient has a dry hacking non‐productive cough and pitting oedema. You suspect that the patient has significant COPD and contact his respiratory physician for further information and his recent investigation results. These are as follows:
   • Forced expiratory volume in 1 second (FEV1) is 38% of normal
   • Recent chest x‐rays showed flattened diaphragm
   • Oxygen saturation (SpO₂) is 90–93% on room air (normal SpO₂ for healthy adults is ~94–99%)
   • Resting heart rate 90–94/minute
   • Respiratory rate is 26 per minute and shallow (normal rate is ~14–20/minute)
5. Given these details, what is your assessment of the severity of his COPD?
   • This patient has severe COPD (low FEV1 and chest x‐ray changes due to lung inflation)
   • High resting heart rate is present and associated with poor outcome, including the development of heart failure
   • Reduced cardiac output causes long‐term muscle wasting and can contribute to weight loss
   • Rapid compensatory breathing rate
6. Following a discussion regarding the poor prognosis of his teeth, the patient asks for all his remaining teeth to be removed. What factors are considered important in assessing the risk of managing this patient?
   • Social
     • Hokkien‐speaking – consider the need for a translator
     • Financial constraints
     • Need for escort/social support
   • Medical
     • Low BMI and malnutrition in COPD are associated with a poor prognosis (a preprocedural full blood count is recommended)
     • The patient has severe COPD which increases the risk of respiratory complications during surgery (hospital‐based care preferable)
     • Currently taking systemic prednisolone and may be at risk of adrenal suppression/crisis (see Chapter 12.1)
     • Hypertension recently diagnosed and may not be optimally controlled
     • Drug interactions:
       • Non‐steroidal anti‐inflammatory drugs can reduce the hypotensive effect of angiotensin‐converting enzyme inhibitors (e.g. enalapril)
       • Theophylline is largely (~70%) metabolised by the P450 isoenzyme; inhibitors or inducers of the isoenzyme can interact pharmacokinetically; ciprofloxacin, erythromycin and tramadol are known to significantly increase plasma theophylline levels; theophylline may reduce the anxiolytic and sedative effects of benzodiazepines
       • Azole antifungals, metronidazole and macrolide antibiotics can potentiate the effects of statins in muscle breakdown (e.g. rhabdomyolysis)
   • Dental
     • Multiple dental extractions required
     • Delayed healing likely (COPD, smoking, malnutrition, systemic steroid)
     • Need for replacement dentures needs to be discussed, including the factors below:
       • Xerostomia secondary to medication (e.g. beta‐2‐agonist) can reduce retention and tolerance to a replacement denture
       • Multiple visits required for denture construction
       • Taking dental impressions may cause respiratory distress if the airway is restricted
       • Irregular attendance/engagement in improving oral health
7. Given the absence of dental pain/acute dental infection, you determine it is advisable to delay treatment until his hypertension is controlled and he has completed his course of prednisolone for the current acute exacerbation of his COPD. When planning his care for the future, should supplemental oxygen be provided to this patient perioperatively?
   • Practices and policies differ widely
   • Hence it is prudent to consult a physician or pulmonologist for patients with moderate to severe COPD as these patients may be dependent on the hypoxic respiratory drive
     • When a patient has long‐standing hypercapnia (high levels of CO₂) and resultant acidosis, the body compensates by retaining more plasma bicarbonate; this attenuates the effect of low pH (acidosis) for the central chemoreceptors, and reduces the stimulus for the main carbonic feedback in physiological respiratory drive
     • It is believed that the effect of hypoxia in peripheral chemoreceptors becomes established as a compensation to reduced hypercapnic effect, in generating the respiratory drive – hence the term hypoxic drive
     • Supplemental oxygen raises blood oxygen level, possibly suppressing the hypoxic drive and may contribute to hypoventilation
     • In reality, the hypoxic and hypercapnic drive exists with many contributors to respiratory drive, including acidosis/alkalosis balance, metabolic demands, neurological states, physical condition of the patient and drug effects
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