Renal System 🫘 Flashcards
What is metabolic acidosis commonly classified according to?
Anion gap
Metabolic acidosis is categorized into normal anion gap and raised anion gap.
What are some causes of normal anion gap metabolic acidosis? (4)
- Gastrointestinal bicarbonate loss: diarrhoea, ureterosigmoidostomy, fistula
- Renal tubular acidosis
- Drugs: e.g. acetazolamide, ammonium chloride injection
- Addison’s disease
What conditions are associated with raised anion gap metabolic acidosis? (4)
- Lactate: shock, hypoxia
- Ketones: diabetic ketoacidosis, alcohol
- Urate: renal failure
- Acid poisoning: salicylates, methanol
What causes metabolic alkalosis?
- Loss of hydrogen ions
- Gain of bicarbonate
It is mainly due to problems of the kidney or gastrointestinal tract.
List some causes of metabolic alkalosis.
- Vomiting / aspiration
- Diuretics
- Liquorice, carbenoxolone
- Hypokalaemia
- Primary hyperaldosteronism
- Cushing’s syndrome
- Bartter’s syndrome
- Congenital adrenal hyperplasia
What conditions may lead to respiratory acidosis?
- COPD
- Decompensation in respiratory conditions (e.g. life-threatening asthma, pulmonary oedema)
- Sedative drugs: benzodiazepines, opiate overdose
What are common causes of respiratory alkalosis? (6)
- Anxiety leading to hyperventilation
- Pulmonary embolism
- Salicylate poisoning
- CNS disorders: stroke, subarachnoid haemorrhage, encephalitis
- Altitude
- Pregnancy
What is the most commonly isolated pathogen in acute bacterial prostatitis?
Escherichia coli
What are risk factors for acute bacterial prostatitis?
- Recent urinary tract infection
- Urogenital instrumentation
- Intermittent bladder catheterisation
- Recent prostate biopsy
What are the features of acute bacterial prostatitis?
- Pain referred to perineum, penis, rectum, or back
- Obstructive voiding symptoms
- Fever and rigors
- Tender, boggy prostate gland on digital rectal examination
What accounts for 25% of drug-induced acute kidney injury?
Acute interstitial nephritis
List some common causes of acute interstitial nephritis.
- Drugs: particularly antibiotics (e.g. penicillin, rifampicin, NSAIDs, allopurinol, furosemide)
- Systemic disease: SLE, sarcoidosis, Sjogren’s syndrome
- Infection: Hanta virus, staphylococci
What are the histological features of acute interstitial nephritis?
Marked interstitial oedema and interstitial infiltrate in the connective tissue between renal tubules
What are common symptoms of tubulointerstitial nephritis with uveitis (TINU)?
- Fever
- Weight loss
- Painful, red eyes
How is acute kidney injury (AKI) characterized?
Reduction in renal function following an insult to the kidneys
What percentage of hospitalized patients develop acute kidney injury (AKI)?
Approximately 15%
What are the traditional categories of causes of AKI?
- Prerenal
- Intrinsic
- Postrenal
What are examples of prerenal causes of AKI?
- Hypovolaemia secondary to diarrhoea/vomiting
- Renal artery stenosis
What intrinsic causes may lead to AKI?
- Glomerulonephritis
- Acute tubular necrosis (ATN)
- Acute interstitial nephritis (AIN)
- Rhabdomyolysis
- Tumour lysis syndrome
What are examples of postrenal causes of AKI?
- Kidney stone in ureter or bladder
- Benign prostatic hyperplasia
- External compression of the ureter
What are risk factors for acute kidney injury (AKI)?
- Chronic kidney disease
- Other organ failure/chronic disease
- History of acute kidney injury
- Use of nephrotoxic drugs
- Age 65 years or over
- Oliguria
- Neurological or cognitive impairment
What are two key ways AKI may be detected?
- Reduced urine output (oliguria)
- Fluid overload
What blood tests are commonly used to detect AKI?
- Sodium
- Potassium
- Urea
- Creatinine
What criteria can be used to diagnose acute kidney injury (AKI)?
- Rise in serum creatinine of 26 micromol/litre or greater within 48 hours
- 50% or greater rise in serum creatinine within the past 7 days
- Fall in urine output to less than 0.5 ml/kg/hour for more than 6 hours