Clinical Scenario

A 49‐year‐old male undergoing haemodialysis for end‐stage chronic kidney disease (CKD), is referred by his nephrologist for an oral assessment. The request is to eliminate potential oral foci of infection prior to planned kidney transplantation.

Structured Learning

1. On oral examination, you note that the patient has marked halitosis, despite brushing his teeth up to 3 times a day. What could be causing this?
   • High salivary urea levels and decomposition of urea into ammonia increases halitosis in people with kidney disease
   • The patient may also be fatigued easily and hence fail to brush his teeth effectively
2. The patient informs you that he also has a metallic taste in his mouth which improves temporarily after a dialysis session. Is there a correlation?
   • Dysgeusia (abnormal taste) is common in those with CKD
   • It may contribute to a poor nutritional intake
     

     

   • It has also been related to the urea content in the saliva and its subsequent breakdown to ammonia and carbon dioxide by bacterial urease
   • Temporary improvement after dialysis has been reported
   • Xerostomia may also contribute to altered taste perception

3. Is this patient’s high level of dental decay also related to his CKD?
   • Patients with end‐stage renal disease have not been found to have a higher risk of dental decay
   • Elevated salivary urea levels have been suggested as a mechanism that protects the tooth against demineralisation, which render the salivary pH alkaline, even after dialysis
   • This patient’s high levels of dental decay are more likely to be related to his limited access to dental care, ineffective toothbrushing, fatigue and potentially xerostomia (restricted fluid intake)
4. The patient appears very tired and short of breath. What could be contributing to this?
   • CKD is associated with a reduced red blood cell count and anaemia due to:
     • Lack of erythropoietin, a growth factor predominantly produced in the kidneys that stimulates the production of red blood cells
     • Iron deficiency as a result of nutritional insufficiency or due to increased blood loss
     • Shortened red cell survival due to uraemia
   • CKD also increases the risk of cardiovascular disease due to:
     • Dyslipidaemia which occurs due to downregulation of lipoprotein lipase and the LDL receptor, and increased triglycerides due to delayed catabolism of triglyceride‐rich lipoproteins; this can result in increasing arteriosclerosis
     • Diastolic ventricular dysfunction
5. The patient agrees to proceed with dental extractions of the retained roots and the teeth that are unrestorable. He is concerned that his jawbone may break during these, as he has been told by the renal physician that his bone is ‘weak due to his renal disease’. What are the risks?
   • Mineral and bone disorder in CKD is common in patients receiving dialysis (e.g. osteoporosis and secondary hyperparathyroidism)
   • Patients have a high rate of vitamin D deficiency, exacerbated by the reduced ability to convert 25‐(OH) vitamin D into the active form, 1,25‐dihydroxy‐vitamin D, by the kidneys
   • Hypocalcaemia arises as a result of phosphate retention and calcium loss in kidneys in chronic renal failure
   • This stimulates parathyroid hormone release and leads to secondary hyperparathyroidism and progressive bone loss, with calcium release from bone by increasing the osteoclastic activity
   • The earliest radiographic indication related to jawbones is the ground‐glass appearance that emerges due to the replacement of bone tissue by connective tissue with cortical bone resorption, lamina dura and trabecular bone loss
   • Osteitis fibrosa cystica (brown tumour) may eventually result
   • Caution is advisable when undertaking extractions to avoid the risk of iatrogenic fractures
6. What factors are considered important in assessing the risk of managing this patient?
   • Social
     • Lives alone – no suitable carer/escort
     • Financial limitation
     • Dependent on hospital transport
   • Medical (related directly to CKD)
     • Anaemia and associated fatigue
     • Prone to bleeding
       • Predominantly due to abnormalities in primary haemostasis, particularly platelet function disorder and impairment of the platelet–wall interaction
       • Thrombocytopenia is detected in about 50% of patients undergoing haemodialysis
     • Increased susceptibility to infections due to:
       • Azotaemic state (high levels of nitrogen‐rich compounds, such as urea and creatinine in the blood) altering innate immunity
       • Changes in the gastrointestinal microbiota suppress both innate and adaptive immunity
       • Immune responses may also be impaired by poor nutritional status, malnutrition and vitamin D deficiency
     • Arterial hypertension (see Chapter 8.1), a common and often poorly controlled finding, with sodium and volume excess as the prominent mechanism; it may also contribute to increased bleeding risk
     • Osteoporosis (see Chapter 7.1), another prevalent condition in haemodialysis patients due to low bone formation rates, even when bone resorption may be normal
     • Avoid prescription of drugs that are metabolised by the kidneys
   • Dental
     • Prone to oral infections and premature edentulism
     • No commitment to long‐term care
     • The procedure should be scheduled the day after the dialysis session (patient often tired and avoids increased bleeding risk due to heparin given at the time of dialysis)
7. Due to the need to raise a flap and remove some bone to extract the remaining tooth roots, you decide to administer an antibiotic postoperatively. What regimen would you recommend without having to adjust the dose?
   • Administer clindamycin (300 mg/8 h) or azithromycin (500 mg/24 h)
8. When prescribing analgesics after surgery, what medications are contraindicated?
   • Ibuprofen and diclofenac are contraindicated for moderate and end‐stage renal disease
   • Tramadol is also contraindicated for end‐stage renal disease

General Dental Considerations

Definition