Week 227 Acute Renal Failure Flashcards
Week 227
What is the function of the kidneys?
- Homeostasis
- Regulation of volume and composition of ECF
- Disposal of waste products
- Hormone secretion and modification
Week 227
Where and how is glucose absorbed by the kidneys?
- Proximal convoluted tubule
- secondary active transport
- Disrupted in dm 2
Week 227
How can we assess Glomerular filtration?
- Average GFR (Glomerular filtration rate) is 125ml/min or 70kg male
- Insulin is most accurate but rarely given as must be given IV
- GFR = Insulin(urine) x Urine flow rate/{insulin in blood]
- Creatinine is other option. Produced at constant rate in health
- This gives an estimation of GFR, but it’s not as accurate, as small amount secreted into PCT.
Week 227
The Proximal convoluted tubule is responsible for the reabsorbtion of what?
- 2/3 of water
- 2/3 of Na, K, Cl, PO4
- Glucose (2ndary AT)
- If glucose > than 12 mmol/l, transporters become saturated and so some glucose makes its way into the urine.
- *Also responsible for the secretion of penicillin, ferusemide, and H+ ions.
Week 227
What are the functions of the distal convoluted tubule?
- H+ regulation
- Actively excretes H+ in response to high pHs
- H+ combines with NH3 and PO4 in tubular fluid
- HCO3 forms from CO2 –> H2CO2 –> HCO3, which then returns to blood
- K, Na, Ca regulation
- Production of prostaglandins (caused by low sodium after increased NA+ resorbtion) Which does two things:
1.) Causes afferent arteriolar dilation (directly)
2.) Causes the JGA to produce renin (think back to your renin - angiotensin - aldosterone system = an increase in blood pressure.
Week 227
What is the effect of ADH on the collecting duct of the kidney nephrons?
Basically, encourages aquaporin incorporation. This massively increases water reuptake, which saves water! Woo! OK, it’s 2:30 am now, I’m going to sleep.
NO really.
I’m actually going to sleep. I’ve been writing these goddamned flashcards for EIGHTEEN HOURS.
Week 227
Which drugs can you think of that would cause Hypokalaemia?
Thiazide diuretics (i.e. indapamide and metolozone)
Loop Diuretics (i.e. Furosemide)
Week 227
Which drugs can cause Hyperkalaemia?
ACEI i.e. Remipril
Angiotensin Receptor Blockers (they end in “sartan”).
Sprionolactone (This is pottassium sparing diuretic)
Week 227
Long term use of which drugs may cause irreversible renal damage?
Aminoglycosides (i.e. Gentamycin)
NSAIDS
Week 227
Which drugs will cause a falsely elevated seum creatinine?
- Trimethoprim
This intereferes with renal metabolism/excretion of creatine
Week 227
Which drugs can cause hypercalcaemia, and increased calcium excretion in urine/renal stones?
Calcium preparations
Vitamin D
Week 227
Which drugs can cause high serum uric acid/urate?
Chemotherapy for bulky tumours
Week 227
Which drugs cause rhabdomyolysis/high creatanine kinase?
- Statins (i.e. atorvostatin)
- Calcineuin inhibitors (Cyclosporin/tacrolimus)
Week 227
Which investigation will best help identify the cause of renal disease in a patient that has presented with ARF, chest symptoms, urine dipstick with blood +++ and protein +++?
Renal biopsy.
Week 227
Which investigation is the most appropriate in a patient that has presented with ARF, fever, night sweats, dysuria, and loin pain?
Urine microscopy looking for white cell casts, urine culture (basically, this is an infection picture, and your tests wil go on to reflect that)
Week 227
Which investigation would be most appropriate for an elderly patient that developed ARF four days post hip surgery?
Urinary Na:
Surgery results in both an increase of catabolic hormones and cytokines. The main effect is the increased secretion of ADH, which will result in water retention. Increases in aldosterone (through activation of the renin–angiotensin system) coupled with increased glucocorticoids cause sodium and water retention and potassium loss. Plasma renin activity is also elevated as a result of a decrease in circulating blood volume. Thus, alterations in overall fluid and electrolyte homeostasis occur because of impaired water excretion, impaired sodium excretion, and increased excretion of potassium.
Week 227
What is the most appropriate investigation for a patient with symptoms of pulyuria, nocturia, hesitancy, and a gradual rise of serum urea and creat
Physical examination and bladder scan. This could well be a prostate cancer, or a metaplasic change within the bladder. Physical exam and uss of bladder would be best.
Week 227
What is the electrolyte abnormality likely to be associated with ARF after a marathon?
Hypocalcaemia. This occurs after strenuous exercise. Especially in the heat!
Week 227
Which electrolyteimbalance would you expct to see in a patient that was in the recovery phase of ARF that was due to rhabdomyolysis?
Hypercalcaemia.
Why?
This is related to the massive calcium uptake in the ischemic muscle cells during oliguria, followed by a muscle calcium release later in the polyuric stage of ARF.
Week 227
Which electrolyte imbalance would most likely be associated with ARF after introduction of ramipril in a patient with chronic heart failure?
Hyperkalaemia.
This is rare with this class of drugs, but it IS a side effect as noted in the BNF!
Week 227
Which electrolyte imbalance is most commonly associated with chronic use of thiazide diuretics?
Hypokalaemia. This isn’t reabsorbed well, and with the SOA of thiazides being in the DCT, K just gets flushed out! Perhaps try potassium sparing like spirinolactone.
Week 227
Which pathology is suggested when urinary RBC casts are found?
Post streptococcal glomerulonephritis (acute inflammation)
Week 227
Which pathology is suggested if urine shows WBC casts?
Acute pyelonephritis
Week 227
Which pathology is most commonly associated with fatty casts in urine?
Nephrotic syndrome, also called nephrosis, causes massive proteinuria, which drops serum protein levels considerably. It also results in hyperlipidaemia and hypercholesterolaemia.
Week 227
Which pathology is most commonly associated wih pigmented urinary casts?
Rhabdomyolysis, The destructin of muscle cells releases myoglobin, which stains things!
Week 227
Which biochemical abnormailty would be MOST likely seen in a first time marathon runner?
HIgh creatinine kinase. Although you would also end up being hypocalcaemic, the clue is the “first time” AKA tonnes of muscle damage! ouch!
Week 227
Which biochemical abnormality are you most likey to see in a patient that is using ACEI for treatment of hypertension?
Hyperkalaemia.
Week 227
Which biochemical abnormality is most commonly associated with ecstasy use?
Hyponatraemia
Week 227
Which biochemical abnormality is most commonly associated with Prostatic carcinoma?
Metabolic acidosis.
Week 227
Which biochemical abnormality is most commonly associated with chemotherapy for a bulky sarcoma of the right thigh?
Hyperuricaemia, This is exogneous purines formed within cells are released, and broken to to urate/urea, before excretion. Chemo kills loads of cells, so this totes blates makes sense. Word.
Week 227
Which drugs will cause an AKI with hyperkalaemia?
ACEI can cause this, and so can potassium sparing diuretics, like spironolactone.
Week 227
Which drugs can cause AKI with hypercalcaemia?
Anything that pumps calcium in, so Vit D and Oral calcium.
Week 227
Which drugs can cause AKI with high creatinine kinase?
Statins and cyclosporin
Week 227
Which drugs can cause AKI with hyponatraemia?
Loop diuretics and thiazide diuretics can cause this.