PATHOLOGY - Chronic Kidney Disease Flashcards
(64 cards)
What is chronic kidney disease (CKD)?
Chronic kidney disease (CKD) is a progressive, often irreversible loss of functional renal tissue
What is chronic kidney failure?
Chronic kidney failure is endstage chronic kidney disease where there is azotaemia and reduced urine concentrating function
Describe the pathophysiology of chronic kidney disease (CKD)
There will be a trigger for chronic kidney disease (CKD) which results in nephron damage. Prolonged injury and damage to the nephrons will result in the infiltration of inflammatory cells and profibrotic cytokines which will result in renal hypoxia and further damage. As the nephrons are damaged, the remaining functional nephrons will have to compensate and filter more blood. In the early stages of disease, the remaining nephrons will hypertrophy to increase their glomerular filtration rate and filter more blood, however, in the later stages of disease, these compensatory mechanisms will become overwhelmed resulting in clinical kidney disease. When there is less than 1/3 of functional nephrons remaining, this will result in impairment of urine concentration and where there is less than 1/4 of functional nephrons, the patient will develop azotaemia. As the disease and azotaemia progress, uraemia will develop
What is the most common cause of chronic kidney disease (CKD) in cats?
Chronic interstitial nephritis
What is the most common cause of chronic kidney disease (CKD) in dogs?
Glomerulonephritis
What are the potential consequences of chronic kidney disease (CKD)?
Azotaemia
Uraemia
PUPD
Hyperphosphataemia
Renal secondary hyperparathyroidism
Hypokalaemia
Anaemia
Systemic hypertension
Haemorrhage
Proteinuria
Metabolic acidosis
How does chronic kidney disease (CKD) cause hyperphosphataemia?
Phosphate is usually excreted via filtration through the glomeruli, however, when the glomerular filtration rate (GFR) is reduced, this will reduce the excretion of phosphate resulting in hyperphosphataemia
How does chronic kidney disease (CKD) cause renal secondary hyperparathyroidism?
Chronic kidney disease (CKD) causes a decreased glomerular filtration rate (GFR) which will result in hyperphosphataemia. Serum phosphate forms complexes with serum calcium resulting in decreased levels of calcium and hypocalcaemia. Furthermore, renal tissue damage results in decreased calcitriol release resulting in decreased dietary calcium absorption in the gastrointestinal tract and hypocalcaemia. In response to hypocalcaemia, the parathyroid gland will release parathyroid hormone which will increase gastrointestinal absorption of calcium and mobilise calcium in the bone. This can result in osteopenia, tooth loosening and pathological fractures. Furthermore, parathyroid hormone is throught to be a uraemic toxin and thus can exacerbate uraemia and cause further renal tubular damage
How does chronic kidney disease (CKD) cause hypokalaemia?
Decreased dietary intake due to inappetence
Increased loss due to vomiting and diarrhoea
Decreased renal reapsorption of potassium
Renal tubular acidosis
How can hypokalaemia present clinically?
Neuromuscular weakness
Arrhythmias
Metabolic acidosis
PUPD
What is a key sign of neuromuscular weakness secondary to hypokalaemia?
Ventroflexion of the neck
How does hypokalaemia promote PUPD?
Hypokalaemia promotes PUPD as adequate serum potassium is required for effective function of antidiuretic hormone (ADH) which triggers reabsorption of water at the collecting duct
How does chronic kidney disease (CKD) cause anaemia?
Chronic kidney disease results in decreased erythropoietin production which can result in anaemia which can promote further kidney disease due to renal hypoxia
Which anaemia results due to chronic kidney disease (CKD)?
Non-regenerative, normocytic normochromic anaemia
How does chronic kidney disease (CKD) cause hypertension?
Chronic kidney disease (CKD) can cause hypertension as chronic kidney disease (CKD) will result in impaired sodium excretion resulting in hypernatraemia. Furtheremore, the renin-aldosterone-angiotensin system (RAAS) which will trigger hypertension
What are the risks of systemic hypertension secondary to chronic kidney disease (CKD)?
Systemic hypertension can cause target organ damage to the kidneys, brain, eyes and cardiovascular system
How can chronic kidney disease (CKD) cause haemorrhage?
Chronic kidney disease can cause ocular haemorrhage secondary to systemic hypertension as well as gastrointestinal haemorrhage secondary to ulceration due to gastrointestinal irritation due to uraemic toxins
However this is rare
How can chronic kidney disease (CKD) cause metabolic acidosis?
Chronic kidney disease (CKD) results in decreased excretion of H+ in the urine resulting in metabolic acidosis. Furthermore, chronic kidney disease causes vomiting and diarrhoea which also results in bicarbonate loss and metabolic acidosis
What are the two main causes of disease progression in chronic kidney disease (CKD)?
- Persistence of initial trigger of chronic kidney disease (CKD)
- Secondary processes which perpetuate the chronic kidney disease (CKD)
Which secondary processes perpetuate chronic kidney disease (CKD)?
Hyperphosphataemia
Renal secondary hyperparathyroidism
Anaemia
Systemic hypertension
Proteinuria
Metabolic acidosis
Renal inflammation
Renal fibrosis
How do you approach the diagnosis of chronic kidney disease (CKD)?
- Assess history and clinical signs
- Clinical examination
- Haematology and biochemistry
- Urinalysis
- Diagnostic imaging
- Blood pressure
What are the potential clinical signs of chronic kidney disease (CKD)?
PUPD
Haematuria
Weight loss
Lethargy
Anorexia
Dehydration
Vomiting/nausea
Diarrhoea
Abdominal distension
Subcutaneous oedema
Ascites
Systemic hypertension
Acute blindness
Pathological fractures/tooth loosening
Small kidneys on palpation
Anaemia
Pain
What would you typically find on haematology in a patient with chronic kidney disease (CKD)?
Non-regenerative, normocytic, normochromic anaemia
Neutrophilia (if secondary infection)
When would you see a neutrophilia in a patient with chronic kidney disease (CKD)?
You would see a neutrophilia in a patient with chronic kidney disease (CKD) if they had a concurrent renal infection
