W11L5 Part 2 - Acute and Chronic Kidney Disease Flashcards
Acute Renal Failure (ARF) - Types
Prerenal - decreased blood supply - e.g. shock, dehydration and vasoconstriction Postrenal - urine flow is blocked - stones, tumours, enlarged prostate Intrinsic - kidney tubule function is decreased - e.g. ischaemia, toxins, intratubular obstruction
Radiocontrast Agents and their Association with ARF
Giving N-acetylcysteine reduces the risk of ARF by 50% in a meta-analysis
Recommended for clients at risk of renal failure who are receiving radiographic contrast media
- diabetics, clients with sepsis
- underlying vascular, renal or hepatic disease
- receiving other nephrotoxic drugs
Difference between Acute Renal Failure and Chronic Kidney Disease
Acute renal failure
- abrupt in onset
- often reversible if recognised early and treated appropriately
Chronic kidney disease
- end result of irreparable damage to the kidneys
- develops slowly, usually over the course of a number of years
Steps of Acute Renal Failure
- Hypoperfusion (reduced blood flow), hypotension due to ischaemia, toxic injury e.g. radiology contrast
- Acute tubular necrosis
- Abrupt loss of function
- Oliguria, anuria
- Hyperkalaemia
- Cardiac arrest
- Death
Steps of Chronic Renal Failure
- Atherosclerosis, chronic glom/nephritis, hypertension, diabetes, pyelonephritis urolithiasis, hydronephrosis
- Retention of nitrogenous wastes, impaired secretion of electrolytes and hydrogen ions
- Uraemia, abnormal water and electrolyte balance, acidosis
- CNS depression
- Coma
- Death
Causes of Chronic Kidney Disease
Changes leading to nephron damage - hypertension - diabetes mellitus - cancers - autoimmune disorders - diseases of the heart or lungs, liver - chronic use of pain medication (e.g. Phenacetin) Changes directly related to the kidney - removal of one kidney - polycystic kidney disease - obstructions of the urinary tract - glomerulonephritis
Clinical Effects of Chronic Kidney Disease - Overview
Nitrogenous waste accumulation - urea first to increase
Alterations in water, electrolyte, & acid-base balance
- decreased serum phosphate, serum Ca2+ and vit D synth
- PTH increased
Mineral & skeletal disorders
- bone reabsorption & altered remodelling
Anemia & coagulation disorders
- bone marrow suppression, decreased EPO, haemolysis
Hypertension & alterations in cardiovascular function
- increased vascular volume, increase renin angiotensin system
Cardiovascular Consequences of CRF
Decreased blood viscosity
- due to less erythropoietin => anaemia
Increased blood pressure => increased workload of left side of heart
- => left ventricle hypertrophy
Not enough oxygen to support LV contraction => ischaemia, angina etc.
Clinical Effects of Chronic Kidney Disease - Gastrointestinal Disorders
Anorexia, nausea and vomiting are common in patients with uremia along with a metallic taste in the mouth that depresses appetite
Cause of the nausea is decomposition of urea to form NH3
PTH increases gastric acid and associated problems e.g. reflux, haemorrhage
Symptoms disappear after transplant
Clinical Effects of Chronic Kidney Disease - Neurologic Complications
Includes peripheral and CNS functions
Demyelination of nerve fibres possibly from uraemia affects lower limbs with loss of sensation and motor functions
Restless leg syndrome seen in 2/3 of dialysis patients - irritations eased by moving the legs
CNS - reduced alertness, loss of memory, cognitive loss, seizures and coma
Clinical Effects of Chronic Kidney Disease - Immunologic Disorders
Infections are common
Metabolic wastes in blood affect white cells
- uraemia will depress humoral and cell mediated immunity and phagocyte function
Acute inflammatory response impaired
Skin and mucosal barriers have reduced capacity to resist infection
Diagnosis often difficult as CKD patients may not raise a fever
Clinical Effects of Chronic Kidney Disease - Disorders of Skin Integrity
Skin dryness due to sweat and sebaceous gland atrophy
Pruritus (itch) from phosphate crystals deposited as a result of hyperparathyroidism - redness of skin, itchy
Skin integrity under pressure from scratching and needles providing a portal for infection
Bruise easily
Clinical Effects of Chronic Kidney Disease - Sexual Dysfunction
Related to uraemia, neuropathy, altered endocrine function, psychosexual problems and medications
- e.g. antihypertensive drugs
Impotence in 56% of male patients on dialysis
Loss of libido from chronic anaemia and decreased testosterone
Loss of function and libido in women by abnormal levels of progesterone, LH and prolactin, hypofertility
Amenorrhoea common with dialysis
Clinical Investigations of Chronic Kidney Disease
Biochem - urea, electrolytes, creatinine, protein Imaging - pyelogram, CT, US, MRI Cystoscopy Cytology - urine or FNA Surgical biopsy
Uraemia
Urine in blood Renal filtering function decreases - altered fluid and electrolyte balance - resulting in acidosis, hyperkalemia, salt wasting, hypertension Wastes build up in blood - increased creatinine and BUN - toxic to CNS, RBCs and platelets Kidney metabolic functions decrease - decreased EPO - decreased Vit D activation
