Renal Diseases (Nephrology) Flashcards
What are the specialised function of the kidneys
- Excretion of many metabolites and drugs
- Regulation of body fluid and electrolyte balance
- Regulation of acid-base balance
- Endocrine functions
What does the PCT do in terms of the fluid and electrolytes balance
- Actively reabsorbs glucose, amino acids, uric acid and inorganic salts
- Active transports of Na+ controlled by angiotensin II
- Active transport of phosphate suppressed by PTH
- Water follows by osmosis
What does the Loop of Henle do for the fluid and electrolytes balance
- Water continues to leave by osmosis
What does the DCT do to the fluid and electrolytes balance
- More Na is reabsorbed by active transport and still more water follows by osmosis
What does the Collecting Tubule do to the fluid and electrolytes balance
Final adjustment of body Na and water content (ADH and aldosterone)
What are some pre-renal factors of acute renal failure
- Hypotension - haemorrhage/severe burns
- Renal thrombosis
- Sepsis
- Drugs causing renal shutdown (NSAIDs and ACE inhibitors)
What are some renal factors of acute renal failure (ARF)
- Antibiotics - Gentamicin, amphotericin, streptomycin
- Analgesic overdose - aspirin and other NSAIDs, Paracetamol
- Multiple organ failures most often due to trauma or sepsis
- Interstitial nephritis etc.
What are some post-renal factors of acute renal failure (ARF)
- Obstructed urine flow
What is the common management option for acute renal failure (ARF)
Dialysis
What is chronic kidney disease (CKD) characterised by
The presence of kidney damage or reduction in GFR (< 90ml/min) for 3 or more months
Whats the normal GFR for men and women
Male - 130ml/min
Female - 120ml/min
What stages of loss of renal function are there
Early Mild Moderate Severe End-stage renal failure
What are some common causes of Chronic Kidney Disease (CKD)
- Long standing hypertension
- Diabetes Mellitus
- Chronic Pyelonephritis
- Chronic glomerulonephritis
- Polycystic renal disease
- Urinary tract obstruction
- Renal artery stenosis
What are some less common causes of Chronic Kidney Disease (CKD)
- Systemic lupus erythematosus
- Amyloid
- Multiple myeloma
- Gout
- Lead poisoning
- Long term drug use: analgesics, gold, penicillamine
What are some clinical features of Chronic Kidney Disease (CKD)
- Often symptomless in early stages
- Symptoms manifest when kidney function has fallen below 25%
- Blood and immune problems
- Metabolic problems
What blood and immune related symptoms of CKD are there
- Anaemia - toxic suppression of bone marrow/ decreased erythropoietin
- Purpura/bleeding tendency - abnormal platelet production/defective vWF, decreased thromboxane
- Lymphopenia - susceptibility to infections
What metabolic symptoms of CKD are there
- Increased nitrogenous compounds (azotaemia/uraemia)
- Renal osteodystrophy - Phosphate retention -> decreased plasma calcium -> increased pTH activity
- Deficiency of active vitamin D
- Polyuria, Polydipsia, Glycosuria
What are some Gastrointestinal clinical features of CKD
- Anorexia
- Nausea and vomiting
What are some Neuromuscular clinical features of CKD
- Headaches
- Confusion
- Sensory disturbances
- Tremors
- Peripheral neuropathy
What are some Cardiovascular clinical features of CKD
- Hypertension
- Congestive cardiac failure
- Atheroma
- Peripheral vascular disease
What are some Dermatological clinical features of CKD
- Pruritus
- Bruising
- Infections
What investigations can be carried out to diagnose CKD
- Urine examination - red/white cell casts, irate crystals
FBC: - Decreased RBC - anaemia,
- Impaired platelet function -> increased bleeding time
Biochemistry: - Increased urea and creatinine
- Increased potassium and metabolic acidosis
- Increased phosphate -> decreased calcium -> increased PTH
- Renal ultrasound - renal size? Renal obstruction?
- Renal biopsy
What general management methods are there for CKD - basically things that solve the symptoms
- Anaemia: erythropoietin
- Hypertension: ACE inhibitors e.g. captopril
- Fluid retention: Diuretics
- Hyperphosphataemia: Calcium carbonate
- Hypocalcaemia: calcium supplements/Vitamin D3
- Metabolic acidosis: sodium bicarbonate
- High cardiovascular risk: aspirin, statins, smoking cessation
What is the treatment goal of CKD
To slow down or halt disease progression to end-stage renal failure
What analgesics are usually safe for CKD patients and what are best avoided in CKD patients
Safe - Paracetamol
Avoid - Pethidine, Tramadol
What anaesthetics are usually safe for CKD patients and what are best avoided in CKD patients
Safe - Lidocaine
Avoid - NA but prilocaine and articaine is safe but not as safe as lidocaine
What anticonvulsants and sedatives are usually safe for CKD patients and what are best avoided in CKD patients
Safe - Diazepam, Midazolam
Less Safe - Carbamazepine, Lamotrigine, Gabapentine
What does renal dialysis do and when is it used
Removes metabolites and excess water
Used mostly in end stage renal failure
What adverse effects can renal dialysis cause
Due to too rapid or excessive fluid removal - dialysis hangover:
- Hypoxaemia, Haemolysis and hypotension
- Cramps, febrile reaction and cardiac arrhythmias
What long term adverse effects can renal dialysis cause
- Ischaemic heart disease
- Aortic valve calcification
- Dialysis-related neuropathies
What are the 2 main types of renal dialysis
- Peritoneal dialysis
- Haemodialysis
Describe peritoneal dialysis
- Peritoneal membrane acts as natural semi-permeable membrane
- Less efficient than haemodialysis but can be carried out more frequently
- Relatively easy and can be done at home
- Can be travelled with (continuous ambulatory peritoneal dialysis)
Describe Haemodialysis
- Vascular access for introduction of infusion lines (arteriovenous fistula)
- Patient dialysed 3 times a week for 3 hours each session
In which patients is renal replacement therapy the treatment of choice
- Children and patients with diabetic nephropathy
What complications arise with renal replacement therapy
- Transplant rejection
- Immunosuppression induced infection or malignancy
- Increased risk of ischaemic heart disease
What is the dental relevance of CKD
- Dental treatment suited for day after dialysis (heparin effect worn off and for maximal benefit from dialysis)
- Ensure careful haemostasis during surgical procedures
- Haemodialysis can predispose to blood-borne viruses
- Avoid systemic fluorides
- Avoid aspirin and NSAIDs
- Drugs excreted mainly bye diner need to be adjusted post consultation with a renal physician
Renal osteodystrophy: - Loss of lamina dura on intraoral radiographs
- Brown tumours on gingiva
- Osteomalacia
Avoid arteriovenous fistulas arm for intravenous cannulation and venipuncture to minimise risk of: - fistula infection
- thrombophlebitis
What is the dental relevance of renal transplantation
- Patients taking steroids may need steroid cover for stressful
- Transplant patients on immunosuppressants more susceptible to infection
- Transplant patients must be carefully monitored and aggressively treated for infections
- Cyclosporine - increased risk of gingival hyperplasia
- Increased risk of tuberculosis
What is nephrotic syndrome
Glomerular damage resulting in classical triad of:
- Massive proteinuria
- Hypoalbuminaemia
- Oedema
Severe hyperlipidaemia is also often present
What are some of the major risk factors of nephrotic syndrome
Conditions that can damage the kidney e.g. diabetic nephropathy, SLE, amyloidosis
Name some medication and infection related risk factors for nephrotic syndrome
Medications: - NSAIDs - Penicillamine - anti-TNF - Gold Infections: - HIV - Hepatitis B and C - Malaria
What are the clinical features of nephrotic syndrome
- Facial and pedal oedema, ascites, and weight gain due to fluid retention
- Poor nutrition
- Loss of appetite
- Fatigue
- Loss of appetite
What is the dental relevance of nephrotic syndrome
- High blood pressure
- Susceptibility to infection due to loss of IgG in urine
- Loss of cholecalciferol binding protein -> vitamin D def.
- Loss of antithrombin III and increased clotting factors -> hypercoagulability -> thrombosis
- Can lead to acute kidney injury or CKD
- Long term corticosteroid therapy is also a problem
How do you diagnose nephrotic syndrome
- Urinalysis - hyperproteinuria
- Blood test - hypoalbuminemia, hypoproteinaemia, Urea and creatinine for kidney function
- Kidney needle biopsy
What treatment options are there for nephrotic syndrome
- Blood pressure meds - ACE inhibitors and ARBS to decrease BP and protein loss in urine
- Diuretics to control oedema
- Statins to lower cholesterol
- Anticoagulants to prevent clots
- Immunosuppressants to decrease the inflammation that accompanies some of the conditions that can cause nephrotic syndrome
