Renal Diseases Overview

Renal Diseases

• Renal failure is a significant loss of kidney function, where less than 15% of normal glomerular filtration rate (GFR) remains.
• GFR is a blood test measuring kidney function.
• Acute renal failure is potentially reversible.
• Chronic renal failure can lead to permanent renal failure.
• Chronic renal failure is the end result of progressive kidney damage and loss of function.

Stages of Chronic Renal Failure

• Chronic renal failure is classified into four progressive stages, based on the loss of GFR.
• Stages include: diminished renal reserve, renal insufficiency, renal failure, and end-stage renal disease.

Causes of Chronic Renal Failure

• Diabetes is the most common cause of chronic kidney disease in developed countries.
• Chronic infections.
• Prolonged renal obstruction.
• Exposure to toxic chemicals, toxins, or drugs (aminoglycoside antibiotics).
• Hypertension.
• Nephrosclerosis (atherosclerosis of the renal artery).
• Polycystic kidney disease.
• Hydronephrosis (urinary tract dilation).

Symptoms of Chronic Renal Failure

• Anemia.
• Dry skin.
• Loss of appetite.
• Vomiting.
• Bone pain.
• Metallic taste in mouth.
• Headaches.
• Inability to concentrate urine.
• Polyuria/oliguria.
• Edema.
• GFR progressively decreases from 90 to 30 ml/min
• Increased serum potassium.
• Increased blood pressure.
• Weakness and fatigue.

Uremic Stomatitis

• Soft tissue changes: urea secreted in saliva, urease enzyme produced by oral microflora, which liberates free ammonia, damages oral mucosa.
• Painful plaques and crusts on buccal mucosa, dorsum of tongue, and floor of mouth, with gray pseudo membrane exudate and painful ulcers.
• Bleeding diathesis (petechiae and ecchymosis).
• Irritation and chemical injury of mucosa (ammonium compounds).
• Xerostomia (unpleasant taste).
• Burning mouth.
• Uriniferous breath odor.
• Ulcers secondary to anemia and/or viral infection (immunosuppressed).
• Gingival hyperplasia (Cyclosporine and Nifedipine (CCB))

Hard Tissue Changes

• Staining in teeth (iron supplements).
• Reduced caries (urea in saliva).
• Delayed teeth eruption.
• Enamel hypoplasia.
• Tooth mobility (oral manifestations of oxalosis include alveolar bone resorption and external root resorption).
• Increased tooth mobility.
• Pain.
• Open bite.

Oral Manifestations in Hyperparathyroidism

• Teeth appear more radiopaque in background of osteoporotic bone.
• Loss of trabeculation of bone.
• Ground glass appearance.
• Total or partial loss of lamina dura.
• Loss of cortical outlines of inferior alveolar sinus cortex of mandible.
• Pulpal calcifications.
• Multilocular radiolucency.
• Arterial and oral calcification.

Treatment of Chronic Renal Failure

• Careful management of fluids and electrolytes.
• Restriction of dietary protein intake.
• Treatment of anemia.
• Renal dialysis.
• Renal transplantation.

Post-streptococcal Glomerulonephritis (PSGN)

• Cause: Group A beta-hemolytic streptococci (GAHS) serotype 12,4,1.
• Pathogenesis: Throat/skin infection by GAHS, antibodies to streptococcus (anti-streptolysin O) are formed in the circulation, antigen-antibody immune complexes are deposited in glomerular basement membrane.
• Nephritic syndrome is an inflammatory process characterized by hematuria with acanthocytes and RBC casts in urine, proteinuria (< 3.5 g/24 h), hypertension, oliguria, and azotemia.

Clinical Features of PSGN

• Occurs weeks after group A beta-hemolytic streptococcal infections.
• Periorbital and peripheral edema.
• Hypertension.
• Tea- or cola-colored urine.
• Usually self-limiting in children.

Investigations

• Urine analysis.
• Serology.
• Throat swab.
• Renal functions.

Treatment of PSGN

• Mainly supportive care, restriction of fluid and sodium.
• Diuresis within 7-10 days after onset of symptoms.
• 10 days of systemic antibiotic with penicillin V.

References

• AMBOSS.
• Harrison's Principles of Internal Medicine 20th edition (ISBN-13: 978-1259644030).