Nephrology Flashcards
What type of acid-base disorder is seen in those with mesenteric infarcts
Metabolic Acidosis
What conditions are seen in normal anion gaps (metaboic acidosis)
GI bicarbonate loss: Diarrhoea, uterosigmoidostomy, fistula
Renal tubular acidosis
Drugs (Acetazolamide)
Ammonium chloride injections
Addison’s
What conditions cause a raised anion gap (metabolic acidosis)
Lactate (shock, hypoxia)
Ketones (Diabetic Ketoacidosis, alcohol)
Urate: renal failure
Acid posioning (salicylates, methanol)
What defines a normal anion gap
8-14 mmol/L
What medication commonly causes nephrogenic diabetes insipidus
Lithium
What psychiatric drug often causes SIADH
Fluoxetine (SSRIs)
What medication should all diabetic patients with an albumin:creatinine ratio of 3mg/mmol or more be started on
ACEi or ARBs
What does an albumin: creatinine ratio > 2,5 indictae
Microalbuminuria
What is the most likely complication for a patient with CKD on haemodialysis
Ischaemic Heart Disease
When should someone over the age of 45 be referred for painless haematuria
Unexplainied visible haematuria or visible haematuria that persists after UTi treatment
When should someone over the age of 60 be referred for haematuria
Unexplained nonvisible haematuria AND dysuria or raiswed WCC
Why is calcium carbonate given to people with hyperkalaemia
Protects against arrythmias (but doesn’t correct calcium levels)
What should be given to correct hyperkalaemia
Calcium Resonium
ECG changes seen in hyperkalaemia
Peaked t waves
Loss of p waves
Broad QRS complex
Sinusoidal wave pattern
How should hyperkalaemia be managed
IV Calcium Gluconate
Combined insulin/dextrose infusion
Nebulised Salbutamol
Calcium Resonium or loop diuretics
When should dialysis be considered in hyperkalaemia
Persistent + accompanied with AKI
What indicates severe hyperkalaemia
6.5mmol/L or higher
Management of severe hyperkalaemia
IV Calcium Gluconate
Insulin/dextrose infusion (to shift K+ from ECF to ICD)
Stop ACEi
What creatinine changes indicate AKI
> 26 mmol/L in 48 hours
> 50% in 7 days
What urinary output changes indicate AKI
<0.5 ml/kg/hour for more than 6 hours
What eGFR increases the risk of AKI
<60
When should someone with AKI be referred to nephrologist
- Renal transplant
- Unknown cause
- Vasculitis
- Myeloma
- No repsonse to treatment
- Stage 3 AKI
- CKD 4 or 5
- Meets criteria for dialysis
WHen does acute graft failure occur following a renal transplant
6 months
Three signs of an acute graft failure
Pyruira
Proteinuria
Rising Creatinine
What is acute tubular necrosis of graft vs acute graft failure
Acute graft failure is ASYMPTOMATIC vs symptomatic
Acute tubular necrosis happens in teh first few weeks after a renal transplant
What is the preferred method of access for haemodialysis
Arteriovenous fistulas
What drugs should be stopped in an AKI
DAMN:
Diuretics
Aminoglycosides and ACEi
Metformin
NSAIDs
If patients have no identifiable cause for an AKI, what should be the next invetsigation of choice
Renal USS within 24 hours
What NSAID does not need to be stopped in an ANKI
Aspirin if it’s at 75mg (cardiac dose)
When should someone with suspected minimal change disease be given a renal biopsy
ONLY if there is no response to prednisolone
What serum level indicates prerenal acute kidney injury over any oter cause
Raised serum urea:creatinine ratio
What distinguishes Acute tubular necrosis over other causes of AKIs
Hypernatraemia (>30 mmol/L) + low urine outout
Apperaance of urine in prerenal AKI vs acute tubular necrosis
Normal vs brown granular with casts
First line management of rhabdomyolysis
IV normal saline
How long does it take to develop an arteriovenous fistula for haemodialysis
6-8 weeks
What should be given to prevent contrast-induced nephropathy
1L IV 0.9% NaCl
How does Lithium cause nephrogenic diabetes inspidus
Desensitises the kdiney’s ability to respond to ADH
Signs of Anti-GBM disease
Haemoptysis + AKI/proteinuria/haematuria
What is AntiGBM disease
Small vessel vasculitis (goodpasture syndrome)
What osmolality level indicates acute tubular necrosis
<350
What defines stage 1 AKI
1.5-1.9 x baseline
<0.5ml for over 6 hours
What defines stage 2 AKI
2-2.9 from baseline
<0.5 ml urine output >12 hours
What defines stage 3 AKI
3> baseline
How often does a patient require haemodialysis a week
3 times a week
How does a peritoneal dialysis work
Has a high dextrose concentration solution to draw waste products from the peritoneum.
How long does a continuous ambulatory peritoneal dialysis last for
30-40 minutes
What is an automated peritoneal dialysis
Done while the patient is sleeping
At what eGFR should dialysis be considered
5-7 ml/min/1.73 m^2
At what age is peritoneal dialysis considered first-line
2 or younger
At what Na level is dialysis considered
Over 155 or below 120
At what pH level should dialysis be considered in AKI
Under 7
At what ureamic level should dialysis be considered
> 30 mmol/L
Creatinine over 500
What is the most common side effect of haemodialysis
ypotension
Name two contraindications to peritoneal dialysis
Intra-abdominal adhesions and abdominal wall stomas
Obesity, resp disease and hernias (relative)
What is the main complication of peritoneal dialysis
Peritonitis
What happens to CK levels in tubular cell necrosis
Becomes very high (can be caused by rhabdomyolysis)
IgA Nephropathy vs Post-strep glomerulonephritis
IgA Nephropathy happens within DAYS of a sore throat
Post-strep glomerulonephritis happens 1-2 weeks after a URTI
What variables are considered when calculating an eGFR
CAGE:
Creatinine, Age, Gender, Ethnicity
What are the indications for acute renal dialysis
HAVEPEE:
H- Hyperkalaemia
A - Acidosis
V - Volume overload
E- Elevated Urea
P - Pericarditis
E - Encephalopathy
E - Oedema
What is the most common drug that causes acute interstitial nephritis
Amoxicillin
What urine results would indicate acute interstitial nephritis
Raised urinary WCC and eosinophils
Symptoms of Acute interstitial Nephritis
Allergy type reaction: Rash and fever and arthralgia
What defect causes nephrotic syndrome with a hypercoagulable state
Antithrombin III deficiency
What is a major complication of membranous glomerulonephritis
A hypercoagulable state - look out for DVTs
Acute tubular necrosis vs Acut einterstitial Nephritis on urine dip
WCC seen in urine dip vs no raised WCC in urine dip
What defines CKD 1
> 90
What defines CKD 2
6090
What defines CKD 3a
45-59
What defines CKD 3b
30-44
What two thing sar eneeded to define CKD stages 1 and 2
eGFR and supporting evidence (urinalysis or renal USS abnormal)
What screening test is used for adult PCKD
Renal USS
What is the most common infection in those with organ transplants
CMV infection
What is the treatment of choice in those with CMV infections
Ganciclovir
What is the most common extra-renal manifestation of PCKD
Hepatomegaly (hepatic cyst formation)
Where do berry aneurysms commonly occur
Anterior communicating artery and anterior cerebral artery
What is the most common cardiac com[lication of ADPKD
Mitral valve prolapse
What causes a hyperacute rejection of a renal transplant
ABO incompatibility (within minutes of tranpslant)
WHat causes an acute rejection of graft
Cell mediated autoimmunity
What malignancy is secondary to immunosupression from transplants
Squamous cell carcinoma or Luymphoma
Name causes of prerenal AKI
Systolic Heart Failure
Hypoalbuminaemia from decompensated liver disease
Cardiorenal and Hepatorenal syndrome
What symptom is commonly seen across both cardiorenal and hepatorenal syndrome
Hypotension
Name some medications that can cause prerenal AKI
NSAIDs
ACE-i
ARBs
What is pre-renal AKI
Damage to blood vessels supplying the kidney
What is acute tubular necrosis
Damage to the tubules following ischaemia (prerenal AKI)
Name some common compounds that can lead to Acute Tubular Necrosis
-mycins (e.g., gentamicin)
Methotrexate
Myoglobin (rhabdomyolysis)
Uric Acid
What type of syndrome is seen in membranoproliferative glomerulonephritis
Nephrotic syndrome
Proteinuria in nephritic syndrome vs nephrotic syndrome
Nephrotic >3,5 g/day
Nephritic 1-3g/day
What can cause renal artery stenosis
Atherosclerosis
Fibromuscular dysplasia
Symptoms of renal artery stenosis
Persistent Hypertension despite on medication
What causes postrenal AKI
Obstruction of urine from kidneys
What commonly causes postrenal AKI in males
BPH and prostatic cancer
If one ureter is obsturcted, do we end up with postrenal AKi
No
Prerenal AKI vs Intrarenal AKI in urine osmolality
Urine osmolality >500
urine osmolality <500
Why is urine osmolality >500 in prerenal AKI
As RAAS system is activated causing more Na+ retention
What is the acid-base formula that occurs in the body
CO2 + H2O ->/
Where is HCO3- ions regulated in the body (ie., excreted)
Kidneys
How is the level of CO2 regulated by th ebody
Lungs
What is the normal blood pH in th ebody
7.37 -> 7.42
Why do pH levels decrease if there is a loss in HCO3- ions
CO2 + H20 -> HCO3- + H+
So this equiilibrium shifts to the right, causing more dissociation of H2CO3 into H+ ions
If HCO3- ions rise, what happens to the pH
Equilibrium shifts to the left, and the pH rises as less H+ ions are formed
If CO2 levels rise in the body, what happens to the equilibrium
Equilibrium shifts to the right, causing pH to lower
What are the four parameters of acidosis/alkalosis
- pH
- pCO2
- HCO3-
- Compensatory response
What causes metabolic acidosis
Build up of acid in blood causing equilibrium to shift to the left, causing excess HCO3- loss.
Low bicarbonate levels
What symptom is associated with a low pH level (< 7.37)
Hyperventilation to lower pCO2
Why is lowering pCO2 important
Causes less H+ ions to be produced.
What is the formula for the anion gap
Na+ - (CL- + HCO3-)
What does the anion gap show us in metabolic acidosis
The anion gap is high
What defines a high anion gap
> 12
What is a normal anion gap
8-12
What causes the anion gap in metabolic acidosis
An excess in H+ ions cause the equilibrium to shift to the left:
CO2 + H20
Name three ways we can get a high anion gap (increased organic acid production)
Lactic Acidosis: Increased anaerobic respiration causes increased lactic acid
Diabetic Ketoacidosis: Causes increase in ketoacids
CKD: Increase in urea
Name two ways we can get a high anion gap (accidental ingestion)
Oxalic Acid (Antifreeze)
Formic Acid (Methanol)
Salicylates
What three compounds can increase lactic acid production and thus, metabolic acidosis
Propylene Glycol
Iron Overdose
Isoniazid overdose
What acronym tells us about the causes of metabolic acidosis
MUDPILES:
Methanol
Uraemia
Diabetic Ketoacidosis
Propylene Glycol
Iron Tablets/Isoniazid
Lactic Acidosis
Ethylene Glycol
Salicylates
What causes a normal anion metabolic acidosis
A build up of chloride ions instead:
Na+ - (Cl- + HCO3-)
Cl- increases
HCO3- decreases
What is the most common cause of normal anion gap metabolic acidosis
Severe Diarrhoea
Why does diarrhoea cause metabolic acidosis
Inestinal and pancreatic secretions of HCO3- and Cl- cannot be re-absorbed fast enough
How does Type 2 renal tubular acidosis cause a normal anion gap metabolic acidosis
PCT cannot re-absorb HCO3- ions, causing them to decrease
How does Addison’s cause normal anion metabolic acidosis
Adrenal glands cannot produce enough aldosterone, so less Na+ is re-absorbed at the DCT, causing less excretion of H+ = metabolic acidosis
What drug can cause normal anion gap metabolic acidosis
Spironolactone
How does Acetazolamide cause a normal anion gap metabolic acidosis
Reduces HCO3- reabsorption at the PCT
How does IV Saline cause normal anion gap metabolic acidosis
Saline has a pH 5.5, so reduces pH in the blood (rare
What acronym can help us to remember the causes of normal gap acidosis
HARDASS:
H - Hyperalimentation
A - Addison’s
R - Renal Tubular Acidosis
D - Diarrhoea
A - Acetazolamide
S - Spironolactione
S - Saline Infusion
What acronym can help us to remember the causes of normal gap acidosis
HARDASS:
H - Hyperalimentation
A - Addison’s
R - Renal Tubular Acidosis
D - Diarrhoea
A - Acetazolamide
S - Spironolactione
S - Saline Infusion
What range of pCO2 defines if compensation is adequate in metabolic acisosis
28.5 -> 32.5
If the calculated pCO2 < Measured pCO2, what does this entail
Metabolic acidosis WITH associated repiratory acidosis
If the calculated pCO2 is greater than the measured pCO2, what does this mean
Metabolic acidosis with associated respiratory alkalosis
What causes respiratory acidosis
Hypoventilation, causing an increase in CO2
Equilibrium shifts to the right causing an increase in H+ ions
What compensation occurs in respiratory acidosis
The kidneys try to absorb more HCO3- ions to shift the equilibrium to the left (to reduce H+ ions)
How long does the compensation by th ekidneys take
24 hours
Acute vs Chronic respiratory acidosis
Acute: pH is VERY low and HCO3- is normal
Chronic: pH is NORMAL and HCO3- is very elevated
Two causes of hypoventilation
Airway obstruction
Diaphragm or chest wall muscles not working properly (e.g., obesity)
COPD
Opioids etc
What causes metabolic alkalosis
Loss of H+ ions
Describe the compensatory mechanism for metabolic alkalosis
Immediate hypoventilation
Nma eto GI causes of H+ loss
Vomiting
Inability for the pancreas to excrete HCO3- ions
Hyperaldosteronism
What drugs can cause metabolic alkalosis
Using loop diuretics
Antacids (contain HCO3- ions)
What acronym can help us to remember the causes of metabolic alkalosis
LAVA
L - Loop Diuretics
A - Antacid Use
V - VOmiting
A - Aldosterone Increase
What can cause respiratory alkalosis
Hypoxia
Pulmonary Embolisms
High Altitudes
Anything that can cause hyperventilation:
Salicylates overdose (initial)
Anxiety + Panic Attacks
Tumours in the brain
What acronym can help us remember the cuases of respiratory alkalosis
PAST PH
Panic Attacks
Anxiety Attacks
Salicylates
Tumour
Pulmonary Embolism
Hypoxaemia
Why does metabolic acidosis cause hyperkalaemia?
In order for H+ ions to enter the cell, K+ ions have to be pushed out (exchanged).
Lots of H+ ions enter the cells, causes lots of K+ ions to be pushed out -> leading to hyperkalaemia
How do beta blockers cause hyperkalaemia
Block the Na+-K+-ATPase, causing more K+ to be left outside the cell
Why does cell lysis (and apoptosis) cause hyperkalaemia?
Detsruction of cells causes lots of internal K+ ions (ICF) to be released into the ECF
Name three components to tumour lysis sydnrome
Hyperkalaemia
Hyperphosphataemia
Hyperurecaemia
Hypocalcaemia
What injuries cause hyperkalaemia
Crush Injuries
Where does aldosterone act
Collecting Duct
DCT
What cells are responsible for K+ secretion in th ekidneys
Principal cells
What drugs can cause hyperkalaemia and how?
They reduce the effect of aldosterone:
Renin Injbitors
ACE Inhibitors
Angiotensin II receptor antagonist
Selectiev Aldosterone blockers
K+ sparing diuretics
How can acute and chronic Kidney Injruy cause hyperkalaemia
Impair K+ Excretion
What blood test indicates chronic kidney injury
Uraemia
What are the causes for internal balance shifted hypokalaemia
Hyposomolality
How does hyponatraemia cause hypokalaemia
Water moves back into the cells (as the concentration gradient shifts), bringing back K+ ions with it.
How does hyperglycaemic hyperosmolar state cause hypokalaemia
Osmolairty is so high, it can cause osmotic diuresis (K+ lost in the urine)
How does metabolic alkalosis result in hypokalaemia
H+ ions are being secreted from cells to compensate, causing K+ to be exchanged and taken back in - hypokalaemia
How does Insulin effect K+ levels
An increase causes hypokalaemia, a deficiency causes hyperkalaemia
Why does insulin effect K+ levels in the blood
Stimulates Na+=K+= ATPase
What causes an external balance shift hypokalaemia
Reduction in K+ intake: Anorexia, Prolongued fasting and diets
Excretion issues:
Vomiting and Diarrhoea
Sweat (excercise a lot in hot climates)
What causes an increased K+ excretion
Hyperaldosteronism:
Conn Syndrome
Compensated Heart Failure
Cirrhosis
Loop Diuretics and Thiazides
What are the two main readings on an ECG for hyperkalaemia
Tall tented t waves
Widened QRS complexes
Signs of hypokalaemia on an ECG reading
Flattened T Waves
U Waves
Signs of hypokalaemia
Muscle weakness and cramps
Spasms
What cause hypernatraemia
H20 loss
What causes false hyponatraemia
Too much cholesterol
Too much protein (raised) (e.g., multiple myeloma)
Where levels are normal but lab instruments say they’re low
What is hypervolaemic hyponatraemia
Where total H20 is raised but Na+ stays the same (hyponatraemic)
What conditions cause hypervolaemic hyponatraemia
Congestive HF
Cirrhosis
Nephrotic Syndrome
ALL PRESENT WITH OEDEMA
What cause hypovaelamic hyponatraemia
Diarrhoea
Vomiting
Diuretics
Cerebral salt wasting
FLUID loss and Na+ loss
What is cerebral salt watsing
Intracranail injury (e.g., meningitis) disrupt sympathetic nervous system stimulation of the kidneys (causes loss of Na+)
What condition causes euvolaemic hyponatraemia
SIADH
What causes Parathyroid hormone related protein-mediated hypercalcaemia
Squamous cell carcinomas of the lung (mimics the effect of the lung)
What medication can cause hypercalcaemia and how
Thiazide diuretics
Increase ca2+ absorption at the DCT
Symptoms of hypercalcaemia
Stones
Bones
Groans
Thrones
Psychiatric overtones
PLUS resistance to ADH = frequent urination + dehydration
Calcium oxalate kidney stones
Name a genetic condition which can cause hypocalcaemia
DiGeorge Syndrome
What vitamin deficiency can cause hypocalcaemia
Magnesium Deficiency
What condition can result in hypocalcaemia
Pancreatitis (acute)
As destroyed fatty acid tissue of the pancrease from high lipase activity binds to calcium ions in the blood.
What medical proceedure can cause hypocalcaemia
Too many blood transfusions
Signs of hypocalcaemia
More exciteable
Tetany
Chvostick sign (twitching of facial muscles)
Trousseau sign (BP cuff can cause flexion of the wrist and elbow)
Signs of hypocalcaemia on an ECG
Prolongued QT interval
MOst common cause of hypermagnesemia
Kidneys cannot excrete Mg2+
Ingestion of mangnesium drugs or substances
Why does lethargy and reduced deep tendon reflexes occur in hypermagnesemia
Mg2+ is a cofactor that inhibits passage of neurotransmitters onto receptors
How does PTH effect magnesium levels
Stimulates the release of Mg2+ into the blood
How does hypermagnesemia affect hormone levels
Inhibits the release of PTH (hypocalcaemia)
Cardiac symptoms of hypermagnesemia
Bradycardia
Cardiac Arrest
Name four causes of hypomagnesemia
Prolongued malnutrition
Mg2+ not absorbed in the GI tract (PPIs, diarrhoea)
Loop and Thiazide diuretics
What is hungry bone syndrome
Surgical removal of the thyroid causes increased bone formation.
Bone are ‘hungry’ for ions so consume all the Mg2+ in the blood
What electrolyte imbalance causes Torsades de pointes
Hypomagnesemia
Why are hypomagnesemia and hypokalaemia related
Diarrhoea and diuretics cause BOTH
What inherited disease can result in fanconi Syndrome
Wilson’s
What cancer can result in fanconi Syndrome
Multiple Myeloma
How does multiple myeloma cause fanconi syndrome (Kidney Damage)
Plasma cells produce abnormally shaped immunoglobulins which damage the PCT
Signs of Fanconi Syndrome
Damage to the PCT causes loss of HCO3- ions: Renal tubular acidosis type 2 (Metabolic Acidosis)
Damage to PCT causes loss of phosphate ions (hypophosphataemia)
What GI complication can PCKD result in
Divrticulitis
Name three peices of advice to give someone with CKD
Avoid Salt containing food
Avoid phosphate containing foods (e.g., meat and dairy foods)
What happens to phopsphate levels in later stages of CKD
They become very raised (as the kidneys are unable to excrete them)
What is the problem with raised phosphate levels in the blood
Can cause hypocalcaemia
How long should cefalexin/co-amoxiclav be used to treat Pylonephritis
7-14 days
What drugs should be stopped in hyperkalaemia
Digoxin
Beta blockers
If ECG does not normalise with calcium gluconate, what should ve done
Give 10ml every 10 minutes (up to 50ml)
Should calcium gluconate be given in the absence of ECG changes?
No
Name two ways potassium can be shifted into cells
10 units of insulin + 25g glucose
10% glucose infusion over 5 hours + 7.0 mmol/L glucose
Why is glucose given alongside insulin
Prevent hypoglycaemia
What medication is used to remove potassium from the body
Calcium Resonium + Lactulose
If glucos and IV insulin continue to have no impact on hyperkalaemia, what should be done
Dialysis or Sodium Bicarbonate
What is the main presentation of hypercalcaemia (2.8 mmol or less)
Polyuria and Polydipsia
Dyspepsia
At what calcium levels do people get ECG changes
> 3,5 mmol/L
What is the most common cause of raised calclium levels
Primary Hyperparathyroidism
In conjuction with what other serum level does hypercalcaemia indicate dehydration as the cause
Raised albumin
If there is hypercalcaemia in the presence of NORMAL ALP, what is the cause
Myeloma
If there is hypercalcaemia in the presence of raised calcitonin levels, what is the likely cause
B-cell Lymphoma
Managmenet of acute hypercalcaemia
0.9% 2-3L of Calcium to increase urinary output
THEN bisphosphonates
What hormone does phosphate stimulate and why
PTH, hyperphosphataemia in CKD can cause PTH to be released (secondary hyperparathyroidism)
Why do we not get hypercalcaemia in CKD caused secondary hyperparathyroidism
Because PTH mechanisms tend to fail, so phosphates usually stay elecated and calcium levels remain normal
What is the role of ANP
Stops RAAS activation + lowers BP
What diagnostic is used for vesicoureteric reflux
Micturating Cystourethrogram
What investigations is used to check renal perfusion
DTPA
Role of podocytes
Has foot processes which allow filtration in the kidneys
Management of focal segmental glomerulonephiritis
Prednisolone
What is distinctive of rapidly progressive glomerulonephritis under microscopy
Crescent shapes: Aggregated of macrophages and epithelial cells in the Bowman’s capsules
What immunosuppressive agent is used in kidney transplants
Tacrolimus
What does a urine sample show for pre-renal AKI
No proteins and no blood
Management of mild hyponatraemia (130-135 mol/L)
Stop medication causing the issue or check for underlying issues at primary care
Define accelerated progression of CKD
A sustained decrease of 15 in eGFR over 12 months
What albumin:creatinine ratio describes proteinuria that should require referral to nephrology
70 or more
At what urianry albumin: creatinine ratio, should antihypertensives be considered in
<30 mg/mmol
