GI, kidney Flashcards
Functions of the kidney. How much filtrate it clears and urine it makes every day
-2 kidneys exchanges water and salts to produce urine which goes into renal pelvis, ureter, bladder, urethra, then outside world.
-180L of filtrate per day
-1.5L urine
Function and structure of a nephron
-functional unit of the kidney. Converts blood into urine
1-the glomerulus (filtration occurs)
2. Bowman’s capsule (collects filtrate)
3. Proximal tubule (reabsorption)
4. loop of henle (water and nutrient absorption into blood)
5. distal tubule
6. Collecting duct
How many nephrons in a kidney. Does it increase or decrease with age
~1 million
-decreases with age so more likely to have chronic kidney disease
What gland sits on top of the kidney. What hormones it produces
Adrenal gland.
cortisol, aldosterone, adrenaline, and noradrenaline
How is kidney function assessed
-creatine clearance
-Plasma creatine concentration
-estimated glomerular filtration rate
What is creatine. Normal plasma clearance value in females and male. What high and low values suggests
-Creatine is derived from metabolism in skeletal muscles and meat in diet
-95 +/- 20 mL/min in females
-120 +/- 25 mL/min in males
High= low GFR (as glomerulus hasn’t been able to clear filter it)
Low= low muscle mass
What is a healthy GFR. What value do you need dialysis
-125 ml/min = healthy
>100 is normal
<10 you need dialysis [stage 5 CKD]
What patients can estimated GMF not be used in
Only for people with average heights so Cannot be used in pregnant people, amputees, short people
Explain stage 1-5 of chronic kidney disease: the GFR and treatment
1: 90+. Normal function, but urine or structural abnormality.
2: 60-89. Mildly reduced kidney function.
3: 30-59: Moderately reduced renal function.
4: 15-29. Severely reduced Renal function
5. <15. >700 creatine. Endstage kidney failure
Stage 1-3= observe, control BP, address risk factors
Stage 4= Control BP, diet restriction, EPO and vit D supplements. Plan for end stage renal failure.
Stage 5= dialysis, transplant
Risk factors for chronic kidney disease
-diabetes
-old age
-polycystic kidneys
-heart disease, Peripheral vascular disease - renal artery stenosis
- ACEI or diuretics, family history of renal problems
Signs and symptoms of CKD (lots.)
-hypertension
-normocytic normochromic anaemia -tired, pale, unwell
-anorexic, nausea, vomitting, itch, confusion, agitated
-impaired clotting, increased bleeding
-pulmonary and peripheral oedema, cramps, tremor, twitches
-increased infection risk
-osteodystrophy
What blood components increase and decrease in CKD
-Increased BP, creatine, potassium (hyperkalaemia), prostacylin, urea (uraemia)
-low GFR
-reduced EPO (anaemic)
-Low RBC due to marrow fibrosis, renal loss, And increased fragility with consequent early destruction
-reduced vit D and Ca
-reduced vW factor and thromboxane
-impaired platelet adhesion
-metabolic acidosis
How CKD affects drug prescribing
-Reduced rate of elimination of renally excreted drugs = may accumulate e.g. opiates
-Reduced protein binding of acidic drugs (eg. phenytoin)
-increased binding of basic drugs (e.g. lignocaine)
-Nephrotoxic drugs may worsen renal function e.g gentamicin, NSAID’s
-immunosupression
Give examples of drugs to avoid and reduce in CKD
-Gentamycin (used in prophylaxis) is nephrotoxic = AVOID
-Erythromycin =REDUCE or AVOID if transplant and taking ciclosporin. Makes cyclosporin more toxic
-Dose reduction with acyclovir, amoxicillin, ampicillin, cefalexin, and erythromycin
-Tetracyclines other than doxycycline =AVOID
-NSAIDs =AVOID, except in mild kidney impairment
- BDZ excreted in kidney so IV sedation used in tertiary care
Is prophylaxis required for CKD before dental procedures
-Routine prophylaxis is not required for dental procedures, whether they are on dialysis, immunosuppressed transplant patients, have AV fistula
-consider if had infection after previous extraction
Immunosupressants for patients with kidney transplant. Oral side effects
-Prednisolone
-Azathioprine
-MMF
-Tacrolimus, sirolimus
-Cyclosporin A
-predisposition to infection - candiosis, herpes. Increased cancer risk (immune system reduced ability to identify abnormal cells). Cyclosporin can cause gingival overgrowth
Although rare, kidney disease is linked with orofacial digital syndrome. What are the signs and symptoms of this
-cleft palate
-bifid lobulated tongue
-hypo or hyperdontia
-limb and skeletal abnormalities
What does dialysis involve. Where is a fistula created
-remove waste products and excess fluid from the blood when the kidneys stop working properly. It often involves diverting blood to a machine to be cleaned
-patients anticoagulated using heparin (half life 6 hours) to prevent clotting
-arterio-venous fistula at the ACF or wrist (Risk of damage and haemorrhage as very turbulent blood flow)
When is the best time to dentally treat a patient receiving dialysis on heparin
-heparin at time of dialysis to prevent clotting in the circuit
-heparin has short half life.
-Day after dialysis = best time to treat these patients as heparin will have worn off but dialysis will have peaked so renal function optimal
What is nephrotic syndrome
-Proteinuria with hypoalbuminaemia= too much protein in urine
-Leads to oedema (no oncotic pressure, fluid leaks into tissues)
-Can be secondary to poorly controlled type 2 diabetes
Why osteodystrophy can be a feature in kidney disease
-Increased phosphate, decreased plasma Ca
-High PTH which draws calcium out of the bones
-There is a failure in conversion of 25-HCC into 1,25-HCC = leading to secondary hyperparathyroidism
-Also the decreased vit D in CKD causes low plasma Ca
What type of anaemia do CKD patients have
normocytic, normochromic anaemia
due to failure production of erythropoietin
Why CKD can impair haemostasis
-marrow fibrosis (FULL BLOOD COUNT AFFECTED = reduced platelet count and function so clotting issues)
-Impaired platelet adhesiveness
-Decreased von Willebrand’s factor
-Decreased thromboxane
-Increased Prostacyclin (vasodilation)
-Heparinisation – regular for dialysis
Oral and dental considerations for CKD
-Impaired haemsotasis
-Reduced excretion so affects drugs
-Incidence of oral ulceration/ infection increased
-Gingival hyperplasia with ciclosporin
-Beware of skin cancers and increased infection (due to immunosuppression)
-Dialysis patients may experience SIALOSIS
-Palatal and buccal keratosis sometimes seen
-CKD in children= delayed growth, delayed tooth eruption, enamel hypoplasia
-ADVISE PT NOT TO SWALLOW BLOOD POST-EXTRACTION –high protein in blood can exacerbate kidney problems
Causes of acute kidney injury
Sudden changes in physiology
-Pre: Vasodilation and Hypotension -Blood or Fluid loss, hypovolemia, sepsis, Dehydration (eg. diarrhoea), Haemorrhage, reduced cardiac output (cardiac arrest) Liver failure. Anaphylaxis
-Kidney stone causing obstruction. Kidney infection
Meds: NSAIDs, ACE inhibitors, gentamicin, metformin, diuretics
-Post: enlarged prostate, UTI, ureter constriction
Signs of acute kidney injury
-low urine output or changes to colour
-high creatine (low GFR)
-over time electrolytes change, acidosis, retain fluid (heart failure, kidney failure)
-Not producing enough urine means build-up of potassium which can lead to cardiac arrest if untreated
-nausea and vomiting, confusion, high BP, abdominal pain
Similarities and differences between Ulcerative colitis and Crohn’s
-Inflammatory bowel diseases. Genetic and environmental influences. Chronic
-UC= affects large intestine (colon). No oral manifestations (however secondary effects from anaemia)
-Crohn’s= affects anywhere along GI tract from mouth to anus. Oral manifestations
Crohn’s is a transmural process. What is this and consequences
-involves the full thickness of the gut wall
-Can develop fistulae. This can become infected and cause an abscess. Can cause obstruction, cause scarring, become necrotic
Signs and symptoms of IBD. systemic signs. Oral features
-diarrhoea/ constipation, change in bowel habit, bloating fever, fatigue, abdominal pain/ cramping, mucous or blood in stool, reduced appetite and weight loss.
-recurrent mouth ulcers, gingivitis, diffuse lip swelling, angular cheilitis, cobblestoning of buccal mucosa, glossitis (usually secondary to malabsorption and deficiency of iron, vit B12 or folate)
-Eye problems: episcleritis, uveitis
-Anaemia
-arthirits
-vascular complications
-erythema nodosum
-pyoderma gangrenosum
-malabsorption
-gallstones, kidney stones
-increased risk of cancer
List types of granulomatous diseases
Crohn’s disease
TB
Sarcoidosis
Oro-facial granlumatosis
What is proctocolitis and its causes
inflammation of the colonic mucosa extending proximally from 15 cm above the anus
-Causes: IBD, sexual intercourse, radiation, ischameia, infection, antibiotic use
What is toxic megacolon and its causes
-severe inflammation causes stretching and dilation of colon so muscles stop working causing fluid and gas to build up and toxins can leak into blood stream
-increased risk of c.difficile infection
Causes: IBD, infections, inflammation, bowel ischemia, radiation, and certain medications, antibiotics (clindamycin)
Indications for surgery for IBD
-Tx is predominately medical not surgical, as can affect whole chunks of the gut so you don’t want to take out a big chunk to find it recurs somewhere else
-Indications: exsanguinating haemorrhage, failure of medical tx, perforation, suspected cancer
Long term bowel effects of IBD
-ulcer perforation, risk of colon cancer, nutritional deficiencies, intestinal strictures, fistulas, anaemia, liver disease
-prednisolone: adrenal crisis, infection, osteoporosis, delayed healing
