Renal Disorders and Dentistry

Renal Disorders and Dentistry: Main Issues

• Steroid therapy, anticoagulation (Heparin), immunosuppression, drug excretion, and increasing incidence of some disorders are main issues in renal disorders and dentistry.

Points in History

• Chronic Renal Failure (CRF), also known as Chronic Kidney Injury (CKI), nephrotic syndrome, renal transplant, and diabetic nephropathy are key points in the history.
• Related bone disease, "osteodystrophy," can cause bone pain and fractures, presenting as toothache.

Chronic Kidney Injury

• It occurs after progressive kidney damage.
• Low Glomerular Filtration Rate (GFR) persists for over 3 months.
• Early Chronic Kidney Disease (CKD) symptoms include nocturia (frequent nighttime urination) and poor appetite.
• Later CKD manifests as hypertension (high blood pressure) and uremia (high levels of urea in the blood).
• CKD can affect diverse body systems, including cardiovascular, gastrointestinal, neurological, dermatological, hematological, and metabolic systems.

Nephrotic Syndrome

• It is characterized by massive proteinuria (losing protein in urine) with hypoalbuminemia (abnormally low albumin).
• It leads to oedema, typically perioral oedema.
• Perioral oedema may indicate trauma, congenital issues, or neoplastic causes (less likely if bilateral); requires a thorough history.
• Nephrotic Syndrome can occur secondary to diabetic nephropathy.

Nephrotic Syndrome: Risks and Considerations

• Patients often take long-term steroids.
• Electrolyte disturbances and steroid treatment increase the risk of infection.
• Patients are more likely to have cardiovascular disorders.

Renal Transplants

• Graft survival rate is 90% at 1 year.
• Patients are immunosuppressed, usually with a corticosteroid plus a steroid-sparing drug like azathioprine or ciclosporin (which causes gingival hyperplasia).
• Many problems of CKD still exist post-transplant.
• Steroid supplementation needs consideration.
• Reevaluate thinking on antibiotic cover due to the patient's increased susceptibility to infection.
• Renal transplant recipients may still experience electrolyte disturbances.
• Predisposition to oral infections such as oral candidosis, herpes simplex, or zoster virus infections.
• Prophylactic, low-dose aciclovir may be prescribed.
• There is a greatly increased chance of malignant disease, such as skin cancers and lymphomas.

Antibiotic Cover

• Changing thoughts as it is not currently deemed necessary.
• Consult a specialist if a recent transplant was performed within the last 6 months, especially if unsure.

Diabetic Nephropathy

• It is the most common cause of End-Stage Renal Failure (ESRF).
• It may be suspected in patients with rapidly progressing infections in a dental setting.
• Signs include good oral hygiene with bad perio or larger abscesses and random blood glucose tests indicating undiagnosed diabetes.

Renal Osteodystrophy

• Itis an almost universal feature of CKD.
• Results from increased plasma phosphate levels, leading to suppression of plasma calcium and elevated parathyroid hormone (PTH).
• Calcium metabolism is further compromised by disruption in vitamin D metabolism.

Renal Osteodystrophy: Mechanism

• There is a failure in conversion of 25-hydroxycholecalciferol to the active form 1,25 DHCC.
• The kidneys produce 25-hydroxycholecalciferol.
• Low calcium levels in the blood lead to increased parathyroid hormone, resulting in secondary hyperparathyroidism.
• Bone disease may also be secondary to steroid therapy, leading to osteoporosis, and bisphosphonate therapy.

Anaemia in Renal Disease

• It occurs mainly due to a failure in the production of erythropoietin by the kidney, which increases haemoglobin levels in the blood.
• It presents as NORMOCYTIC NORMOCHROMIC ANAEMIA (lack of number of RBCs)
• There may be renal loss of red blood cells, marrow fibrosis, and increased red cell fragility, leading to early destruction.
• Patients tend to have other renal issues.

Haemostasis & Dialysis

• Patients may also have issues with haemostasis, indicated by a low platelet count or badly functioning platelets.
• Marrow fibrosis can lead to a reduced platelet count and poor platelet function.
• Increased red blood cell fragility results in early destruction.

Dialysis Types & Considerations

• Two main types: peritoneal (natural membrane) and extra-corporeal (outside membrane).
• Both types rely on the patient's blood being exposed to a solution hypotonic in metabolites across a semi-permeable membrane.
• Patients are anti-coagulated using heparin, which has a half-life of 6 hours.
• The optimum time for dental treatment is the day after dialysis when Heparin has worn off and renal function is optimal.
• An arterio-venous fistula is surgically formed either at the antecubital fossa (ACF) or wrist.

Arterio-Venous Fistula & Haemostasis

• Never use the fistula for vascular access.
• Palpable 'thrill'

Haemostasis and Examination Findings

• Haemostasis is impaired in CKD.
• Impaired platelet adhesiveness and decreased von Willebrand factor are observed.
  • Decreased thromboxane impairs clotting.
  • Prostacyclin levels are increased, causing vasodilation.
• Oedema, particularly periorbital oedema, is a classic feature.
• Steroid facies include a moon-shaped face.
• Pulmonary/cardiac effusions involve fluid leaking into places it shouldn't be.
• Bone pain indicates renal osteodystrophy.
• There is an increased incidence of oral ulceration and infection.
• Gingival hyperplasia can occur with ciclosporin use.
• Be cautious of skin cancers related to immunosuppression.

Salivary Glands

• Dialysis patients may experience swelling of major salivary glands, especially the parotid gland ('SIALOSIS').
• Sialosis secondary to renal impairment and dialysis is non-neoplastic and non-infective, resulting in enlarged salivary glands.
• It can be seen in alcoholic, diabetic, and dialysis patients.
• An ultrasound scan can be used to check for malignancy.

Oral Examination

• Palatal and buccal keratosis may be present.
• Decreased growth, delayed tooth eruption, and enamel hypoplasia may occur in children with CKD.

Dental Aspects & Prescribing

• Antibiotic prophylaxis is no longer routinely necessary.
• Be aware of the fact that these patients belong to a high-risk group (infection)
• Loss of renal reserve can occur due to a heavy protein load, e.g., swallowed blood into the system.
• Be aware of the patient's cardiovascular status as CKD increases the risk of cardio problems.

Prescribing in Renal Disease: BNF

• Gentamicin (used in prophylaxis) is nephrotoxic and should be avoided
• Erythromycin is contraindicated in patients who have had a transplant and are taking ciclosporin.

Prescribing in Renal Disease

• Dose reduction is necessary with aciclovir, amoxicillin, ampicillin, cefalexin, and erythromycin.
• Tetracyclines other than doxycycline should be avoided.
• NSAIDs should be avoided except in mild impairment.
• Drugs used in dental sedation should be used with care.

Renal Calculi: Basics

• Peak incidence is between 20-50 years of age.
• Has a genetic element.
• Forms in the collecting ducts and can be deposited anywhere in the urinary tract.
• Can often be passed spontaneously and often painful.

Renal Calculi: Risk Factors

• UTI, dehydration, small intestinal disease, hypercalcaemia, and high dietary oxalate intake.
• High dietary oxalate intake is a risk factor, and 39% of calculi are calcium oxalate.

Renal Calculi: Clinical Features

• Kidney stones can be asymptomatic.
• Loin pain (kidney) is present.
• In the ureter, it causes renal (ureteric) colic, from the ureteric duct, from the kidney to the bladder.
• Radiates from the loin to the groin and may be associated with nausea and vomiting.
• Interruption or blockage of urinary flow (depending on the site).
• Suspicion of malignancy if there is blood in a secretion.
• Can cause infection and haematuria.

Renal Calculi: Investigations

• Blood tests e.g. urea and electrolytes (U and E), calcium, and phosphate.
• KUB (kidney, ureter, bladder) X-ray (80% visible stones).
• Renal ultrasound (US).

Renal Calculi: Management

• Often conservative, advise increased fluids, and sometimes they pass spontaneously.
• Large stones: treated with lithotripsy, which breaks the stone into smaller, more easily passed pieces.
• Open surgery is rarely needed (stents, endoscopic).

Renal Colic: Acute Episode

• IV fluids if vomiting.
• Analgesia, e.g., diclofenac (PR) (non-steroidal).
• Possibly opiate and anti-emetic treatment.
• Antibiotics if infection.

Renal Cancer: Warning Signs

• Haematuria should be approached as suspicious of Malignancy, however this is not DIAGNOSTIC
• Loin pain and anorexia.
• Abdominal mass.
• Can metastasize to lymph nodes and lungs.

Wilm's Tumour (Nephroblastoma)

• 90% 5-year survival rate.
• Abdominal mass and haematuria are symptoms.
• Childhood cancer.
• Treatment includes nephrectomy (taking the kidney out), DXT (radiotherapy), and chemotherapy.

Acute Kidney Injury (Acute Renal Failure)

• May be seen in Hypovolaemia
• Fall-off in urine output (normal 30 to 60 ml per hour).
• Medical emergency.
• Potassium level will rise to dangerous levels.

Acute Kidney Injury: Management

• Potassium level must be lowered.
  • Calcium Resonium removes the potassium.
  • Glucose and insulin infusions IV
• Monitor urine output.
• May progress to dialysis.

Summary Considerations

• Be aware of reduced resistance to infection.
• Consider antibiotic prophylaxis – change in thinking.
• Best be careful during local anaesthetic
• Be aware of steroid therapy.
• The day after dialysis is the optimum time for treatment.
• Electrolyte disturbances can predispose to cardiac arrhythmias.
• Anaemia (of chronic disease).
• Impaired drug excretion.
• Dialysis is a consideration