Nephrology Flashcards
Manifestations of high phosphate
Itch/pruitus
Osteodystrophy
Kidney stone disease name
Nephrolithiasis
Types of kidney stone composition
Calcium stones - either calcium oxalate, calcium phosphate.
Others:
Struvite (magnesium, ammonium, phosphate from bacterial infection)
Uric acid (low urine pH)
Cystine (genetic cause).
Risk factors for kidney calculi
Male Obese Dehydration Diet = high animal protein diet Deformity = horseshoe kidney Drugs = vitamin D supplements Diseases = hyperparathyroidism
3 common sites of renal stones
Pelvic-ureteric junction
Mid-ureter at cross over of iliac vessels
Vesicoureteric junction
Signs and symptoms fo renal calculi
Renal colic = sudden onset severe unilateral pain in the loin area and radiated to groin/labia area.
Pain can occur in spasms/intervals but usually constant.
Nausea, vomiting, haematuria.
Hx of dysuria, frequency or straining.
O/E - restless (peritonitis pts are still), pyrexi
Investigations for renal calculi
Non-contrast helical CT of KUB.
Urine dipstick = ++RBC
MSU for ms+c
FBC, CRP, U+Es, serum calcium, phosphate, urate
Pregnancy test in females
Management of renal calculi
1) Analgesia - IM diclofenac.
Anti-emetic - IM Metoclopramide.
2) Hydration - fluids will pass out stones <5mm.
3) Medical expulsion therapy for stones: CCB e.g. Nifedipine or alpha blocker e.g. tamsulosin.
4) ESWL - Extracorporeal shock wave lithotripsy.
5) Ureteroscopy and laser break down.
6) Surgical nephrolithotomy.
Types of polycystic kidney disease
Autosomal dominant (ADPKD) usually adult presentation. Autosomal recessive (ARPKD) much more rare and presents in childhood.
Genes in autosomal dominant polycystic kidney disease
PKD1 coding for protein polycystin 1 (85%) and PKD2 coding for polycystin 2.
Signs and symptoms of PKD
Can be asymptomatic until complication.
ADPKD = nocturia and polyuria ARPKD = childhood onset, abdo mass and renal failure, portal HTN and hepatic fibrosis..
History: Lumbar pain (esp females) Flank discomfort. Dysuria Haematuria LUTS e.g. urgency Symptoms of HTN e.g. headaches. FHx of PKD/ESRD. O/E: Palpable kidney/mass in flank area. HYPERTENSION
Investigations for PKD
KUB USS
Genetic testing.
CT abdo pelvis non-contrast.
Screen for complications:
- intracranial aneurysms with MRI
- ECG or echocardiogram.
Treatment of PKD
SCREEN FAMILY!
Ensure adequate water intake.
Treat symptoms e.g. HTN with ACE-i.
Renal replacement therapy - dialysis, transplant list.
Surgery on cysts
Genetic counselling.
Safety-net advise on SAH and cerebral aneurysms.
Glomerular filtration barrier components
Podocyte
Glomerular basement membrane
Fenestrated capillary endothelium
Flow of blood in nephron
Glomeruli –> proximal convoluted tubule –> descending loop of Henle –> ascending loop of Henle –> distal convoluted tubule –> collecting tubule –> collecting duct.
What makes up the renal corpuscle
Glomerulus and Bowman capsule
Name some functions of the kidney
Eliminate waste products Regulate acid-base balance Regulate blood pressure Regular electrolyte balance Produce erythropoietin Produce renin (juxtaglomerular apparatus) Activate vitamin D
Quick description of RAAS
- Low renal perfusion or increased sympathetic drive = kidneys produce RENIN.
- In liver angiotensinogen is converted to angiotensin I.
- Conversion of angiotensin I to angiotensin II via ACE mostly in lungs.
- Angiotensin II is vasoconstrictor.
- Aldosterone secretion of adrenal cortex under influence of angiotensin II.
- Aldosterone increases sodium and warmer reabsorption in kidneys.
Causes of end stage renal failure
Pyelonephritis
Polycystic kidney disease
Glomerulonephritis
Diabetes
Fanconi syndrome
- Proximal tubule dysfunction leading to acute tubular acidosis.
- Urine has high levels of:
Glucose, phosphate, uric acid, amino acid and high protein:creatinine ratio. - S+S: growth impairment, muscle weakness, Rickets, hypoglycaemia
- Ix: serum anion gap on ABG is normal.
- Rx: need to replace phosphate.
Hydronephrosis
Dilation of renal pelvis commonly due to urine obstruction.
Can be unilateral or bilateral.
If kidney function is affected from urine obstruction = obstructive nephropathy.
Common causes of hydronephrosis
Renal calculi (unilateral) BPH (bilateral) Prostate cancer Bladder cancer Iatrogenic e.g. gynae surgery
Presentation of hydronephrosis
Flank pain Dysuria LUTS Haematuria Fever
O/E:
Distended abdomen and palpable bladder
Ix for hydronephrosis and Mx
Lab:
Urea and creatinine
Urine dipstick
FBC
Imaging:
USS KUB
Non-contrast CT
Mx = treat cause. Analgesia, antibiotics. Ureteric stent, nephrostomy.
Why measure creatinine for kidney function
- Serum creatinine is usually constant.
- Creatinine is freely filtered by glomerulus and not reabsorbed so marker of GFR.
- Estimate GFR with serum creatinine level and a timed urine collection.
Definition for acute kidney injury 💦
Sudden onset renal dysfunction.
KDIGO definitions:
- Rise in creatinine >26micromol/L in 48hrs
- Rise in creatinine >1.5 times baseline creatinine within 7 days.
- Urine output <0.5ml/kg/hr for >6 consecutive hours.
Causes of acute renal failure
·PRE-RENAL = hypovolaemia, reduced cardiac output
e.g. burns, haemorrhage, cardiac failure, cariogenic shock, ACE inhibitors.
·RENAL = vascular glomerular, tubular and interstitial
e.g. thrombosis, scleroderma, glomerulonephritis, rhabdomyolysis, acute tubular necrosis due to SEPSIS, interstitial nephritis.
·POST-RENAL = obstruction
e.g. renal calculi, bladder cancer, BPH
·DRUGS (NSAID, contract, diuretics, ACE inhibitors, penicillins).
Acute tubular necrosis
- Decrease perfusion - sepsis, shock, contrast agents.
- VVVV common cause of intrinsic/renal AKI.
- Ix =Hyperkalaemia, hyperuraemia, high creatinine. Urinalysis = brown granular casts.
Name some nephrotoxic drugs 🤪
Iodinated contrast agents Diuretics ACE inhibitor and Angiotensin receptor blockers NSAIDS Gentamycin Acyclovir
Complications of AKI
Hyperkalaemia Metabolic acidosis Pulmonary oedema Uraemia CKD and ESKD
S+S of AKI
Decreased urine output
Nausea and vomiting
Dizziness, drowsiness, fatigue, altered mental state (uraemia).
Hx of risk factors or causes (DM, prescribed drugs, CHF, muscle cramps).
O/E:
tachycardia, hypotensive, pedal oedema.
AKI and not responsive to fluids cause…
Hepatorenal syndrome
Ix for suspected AKI
· Bloods: ABG or VGB, serum creatinine, U+E (esp potassium!!), LFT, FBC. Find cause e.g. ANCA, ANA antibodies, creatinine kinase (rhabdomylosis)
· Catheterise: urine dipstick, urine sample for microscopy (bence jones protein, cellular casts), urine osmolality, urine sodium.
· Other: ECG, CXR
· Imaging: KUB USS (within 24hrs)
Management of AKI
- Stop nephrotoxic drugs.
- A to E resuscitation including IV fluid bolus (500ml 0.9% normal saline STAT) and catheter.
- Investigate ABG + ECG + KUB USS + urine dipstick.
- Sodium bicarbonate for metabolic acidosis + good ventilatory support.
- If uraemia, severe met acidosis, severe hyperkalaemia = renal replacement therapy e.g. dialysis.
- If due to obstruction - stent.
- Consider need for ITU and vasopressors if not responding to fluid.
- RRT.
Management of hyperkalaemia and what level of K is worrying?
If potassium is >6.5mmol/L or >6mmol/L + ECG changes: ACT NOW 🆘⚠️🆘
·Nebulise salbutamol
·IV 10% calcium gluconate - repeat ECG. This protects the heart but does not treat high potassium.
·10units ACTRAPID + 50ml 50% glucose over 30mins - can do this twice before getting senior, specialist help.
Complications of polycystic kidney disease
Hypertension
Cyst infection
ESRF
Cardiac = aortic root dilation, mitral valve prolapse and other valvular diseases.
metformin and the kidneys
Won’t be exact cause of an AKI but will worsen the injury and increase acidosis.
Why metabolic acidosis in AKI?
Unable to excrete waste organic acids
Definition of chronic kidney disease
Chronic abnormal function or structure of the kidney which goes on for 3 months or more of:
- haematuria +/- proteinuria
- GFR <60ml/minute/1.73m2.
Common causes of CKD
Diabetes mellitus Glomerulonephritis Hypertension Polycystic kidney disease Nephrotic and nephritic syndromes; focal segmental glomerulosclerosis.
GFR and end-stage kidney disease
Stage 5 CKD = GFR <15ml/mine/1.73m2.
Who should be screened/routinely tested for CKD?
Diabetics HTN CHF or IHD SLE Recurrent UTI e.g. BPH
Presentation of CKD
Asymptomatic (apart from symptoms of causative disease), most picked up on routine checks.
Fatigue (anaemic)
Oedema (water and salt retention)
Nausea, pruritus and anorexia (uraemia)
Recurrent UTI
Investigating CKD
Serum creatinine Estimation of GFR using serum creatinine Albumin:creatinine ratio Urine dipstick Urine microalbumin KUB USS Look for cause - OGTT, BP, antibodies for glomerulonephritis cause. Prevent complications - FBC.