Nephrology & Investigations Flashcards
List 5 risk factors for AKI and CKD.
List 5 disease modifiers for AKI and CKD.
List 6 outcomes of AKI and CKD.
Interrelated topics - AKI is a risk factor for CKD and vice versa.
List 5 differences between AKI and CKD?
AKI is common in a hospital setting.
CKD = patients are usually asymptomatic, relies on screening, patients usually referred to the clinic.
What are two systems for defining AKI?
Does this patient have AKI?
AKI Definition: RIFLE (Risk, Injury, Failure, Loss of kidney function)
- Looks at GFR and urine output
Case: Sounds like AKI but doesn’t actually satisfy criteria.
The AKI definitions are more theoretical, useful for epidemiology and research but less useful in the clinical setting.
Give a clinical definition of AKI, what do we see clinically?
Describe the Epidemiology of AKI?
Determine whether the causes of AKI in the following patients are pre-renal, intra-renal or post-renal?
Case 1 = pre-renal
Case 2 = post-renal cause? (can cause hydronephrosis)
Case 3 = Intra-renal (gentamicin nephrotoxicity)
What are the causes of post-renal AKI? How common is this?
Post-renal causes of AKI not very common.
List 3 rare causes of post-renal AKI.
IgG4 = responds well to steroids – causes hydronephrosis.
Need to block off both kidneys to get AKI (if just one and the other one working well it will just compensate but if only one good working kidney gets blocked = AKI)
What is the most common type of AKI? 3 causes?
DnV = Diarrhea and vomiting = dehydration
What should always be assessed in a patient with suspected ARF?
JVP = most important clinical sign for volume status
Explain the effects of NSAIDs on the kidneys.
Explain the effects of ACEIs on the kidneys. How can they be both nephrotoxic and renoprotective?
What are 4 structures within the kidney that can be the target of intra-renal AKI?
What are 4 structures within the kidney that can be the target of intra-renal AKI?
For each of the following cases, which structure within the kidney do you think has been damaged and caused intra-renal AKI?
Case 1 = Tubular
Case 2 = Tubular
Case 3 = Glomerular
Case 4 = Interstitial
What test must you always perform in a patient with suspected AKI?
Usually talking about non-urological causes of haematuria (ie. Not stones, not UTI, not catheter trauma)
What is RPGN?
- Clinically?
- 3 Causes?
- Ixs?
Serum Sodium – Normal = 140mmol/L
Case 1 = Overhydration, so she has sweat a lot but she has over replaced the fluids with clear water (without electrolytes).
Tx = Get the sodium up, she has an acute hyponatraemia, stop her fluids
- Neurological sequelae are common in this instance but acute hypernatraemia from dehydration is far more common
List & Explain 4 causes of Acute Hyponatraemia?
What is the treatment for Acute Hyponatraemia? Who is particularly at risk of death/neurological complications?
What is the likely diagnosis?
= Subdural haematoma
List 4 causes of hyponatraemia?
List 3 causes/mechanisms of Pseudohyponatraemia?
List 4 causes/mechanisms of Dehydrated hyponatraemia?
Osmotic diuresis – eg. Sugar
Thiazides = increase sodium loss whereas Lasix’s (eg. Frusomide) increase your free water loss (gives you a high serum sodium)
Cerebral salt wasting = very rare, dehydrated (vs. SIADH = normovolaemic)
List 3 causes/mechanisms of fluid overloaded (oedematous) hyponatraemia?
RAAS activation
List 2 causes/mechanisms of Euvolaemic hyponatraemia?
What are 4 CNS causes of SIADH (Euvolaemic hyponatraemia)?
Which tumours can cause SIADH (Euvolaemic hyponatraemia)?
What are 7 Drugs that can cause SIADH (Euvolaemic hyponatraemia)?
What are 3 Miscellaneous causes of SIADH (Euvolaemic hyponatraemia)?
How is SIADH diagnosed?
Describe an algorithm to the approach of a patient with SIADH?
What is the treatment for hyponatraemia:
- Dehydrated?
- Overloaded?
- Euvolaemic (SIADH)?
- Life-threatening hyponatraemia?
What is the treatment for SIADH? What can rapid correction result in?
Who can you anticipate will have rapid correction of hyponatraemia in SIADH? (5)
List 4 causes of hypernatraemia?
What is the aetiology of central diabetes insipidus? (2)
List 6 causes of nephrogenic diabetes insipidus?
How is Diabetes Insipidus diagnosed?
What is the treatment of hypernatraemia secondary to diabetes insipidus?
What has she got? What do you expect her electrolytes to be?
Torsades - QT prolonged due to hypokalaemia
What is the distribution of potassium in the body?
List 5 Clinical signs/symptoms of hypokalaemia?
What ECG changes will you see in hypokalaemia?
More prominent U wave and eventually a prolonged QT interval
List 3 Causes/Mechanisms of Hypokalaemia and examples of each?
What is the treatment for hypokalaemia?
List 2 Clinical features of Hyperkalaemia?
What ECG changes will you see in Hyperkalaemia?
Tall peaked T wave
List 3 causes/mechanisms of Hyperkalaemia and give examples of each?
What is the treatment for Hyperkalaemia? Acute? Chronic?
What has she got?
= Hypercalcaemia
What are the Clinical Signs & Symptoms of Hypercalcaemia?
List 4 Causes/Mechanisms of Hypercalcaemia and give examples for each?
- 50% caused by primary hyperparathyroidism and 50% all of the others
What is the treatment for Hypercalcaemia?
Whatman’s cellulose = calcium binder in the gut
List 6 Clinical Signs/Symptoms of Hypocalcaemia?
What are Chvostek and Trousseau signs indicative of?
= Hypocalcaemia
List 9 causes of hypocalcaemia?
What is the treatment for hypocalcaemia?
What has he got?
What are 7 clinical signs/symptoms of this condition?
= Hypophosphataemia
List 4 Causes/Mechanisms of Hypophostataemia and give examples of each of them?
List 3 Causes/Mechanisms of Hyperphostataemia and give examples of each of them?
What are 4 clinical signs/symptoms of Hyperphostataemia?
What is the treatment for Hyperphosphataemia?
Which 2 patient groups are at risk of Hypermagnesaemia?
What are the clinical manifestations:
- At 2mmol/L? (3)
- At 3mmol/L? (4)
- At 5mmol/L? (4)
What is the treatment for Hypermagnesaemia?
What are 4 clinical manifestations of Hypomagnesaemia?
What are 4 Causes/Mechanisms of Hypomagnesaemia and give examples for each of them?
What is the treatment for Hypomagnesaemia?
What are the three major pathophysiologic etiologies for acute renal failure (ARF)?
List 5 Causes/Mechanisms of Prerenal AKI and given examples for each of them?
List 4 Causes/Mechanisms of Intrarenal AKI and given examples for each of them?
List 3 Causes/Mechanisms of Post-renal AKI and given examples for each of them?
Which drugs are nephrotoxic?
Describe the pathophysiology of Pre-renal AKI?
Prerenal AKI
Decreased blood supply to kidneys (due to hypovolemia, hypotension, or renal vasoconstriction) → failure of renal vascular autoregulation to maintain renal perfusion → decreased GFR → activation of renin-angiotensin system → increased aldosterone release → increased reabsorption of Na+, H2O → increased urine osmolality → secretion of antidiuretic hormone → increased reabsorption of H2O and urea
Creatinine is still secreted in the proximal tubules, so the blood BUN:creatinine ratio increases.
What are the 4 phases of AKI and the Characteristic features and duration of each?
What are the clinical features of AKI? (10)
Understand the use of ACE-Is and ARBs in the management of CKD.
- List 6 Benefits of their use in CKD
What should all people with CKD be prescribed?
- Australian and international guidance is clear on medicines for chronic kidney disease (CKD) that slow CKD progression and reduce cardiovascular (CV) risk.
- All people with CKD should first be prescribed an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB).
Define CKD.
What determines the management of CKD?
How frequently should someone with a:
- moderate
- high
- very high
CKD development risk be monitored? What clinical assessment should be involved?
eGFRs for each risk level?
What lab tests should be performed for each of the levels of CKD Risk?
- 5 for all levels?
- 3 additional for orange and red?
Which other assesments and measures should be performed for each of the levels of CKD Risk?
- 2 for all?
- 2 for orange and red?
- 2 for red?
Describe the non-pharmacological management of all CKD patients? (5)
Describe the pharmacological management of all CKD patients? Red Risk?
Explain the Algorithm for medicines that slow CKD progression and reduce CV risk for people with CKD.
Describe how Ken’s CKD management in terms of his ACE inhibitor should be changed?
- What is your target?
- What tests will guide your therapy?
What should be done to manage Ken’s BP from a CKD prevention point of view?
- Target BP?
- Steps?
Other than up-titrating Ken’s dose of ACE inhibitor to the max and controlling BP with an antihypertensive, what other medical could be considered in this case?
- What PBS listing criteria does he meet?
- Recommended dose?
What is the HbA1C target in patients with CKD and Diabetes?
The target for people with CKD and type 2 diabetes is HbA1c ≤ 7% or ≤ 53 mmol/mol.
- 5 Indications for RRT?
- List the indications for urgent RRT (AEIOU)?
- List the dialyzable medications and poisons (I STUMBLED)?
What are the 2 Mechanisms and 2 Modalities of RRT?
What are the basic principles of Hemodialysis and of Hemofiltration?
List the complications of Haemodialysis:
- 5 Vascular access complications?
- 2 Cardiovascular complications?
- Bleeding risk?
- 3 Other?
- What is Dialysis disequilibrium syndrome?
What are the basic principles of peritoneal dialysis?
- Mechanism?
- Administration options?
- Catheter?
List 3 Complications of peritoneal dialysis?
What are the indications for Computed tomography CT scans?
List 3 Complications of CT scans?
List 7 Radiological investigations?
- What are xrays?
- Do they involve radiation?
- What is digital radiography and its benefits?
- List 4 things xrays are the first line investigation for?
First Line for:
1. Trauma
2. Musculoskeletal
3. Chest imaging
(Abdominal xray)
What are the indications for barium investigations?
- Swallow? Meal? Enema?
Fluroscopy:
- Real time images produced by xrays
- X-rays, fluorescent plate, image intensifier, monitor
- Commonly used for GI studies - eg. barium work
What is Computerised Tomography?
Which units does it use?
Water = 0 and air/fat is less dense than water (<0) and bones/soft tissues are more dense than water (>0)
What are the CT Housefield units for cancellous vs. cortical bone?
cancellous (>200) vs. cortical bones (>400)
Give 2 examples of extremely dense structures that can cause an issue with CT imaging? Why?
= loss of information when there are extremely dense structures as they cause artefacts on the imaging
What is IV Contrast?
Distribution in the body?
Excretion?
What are 5 contraindications to IV contrast? What eGFR?
- Asthma not an absolute contraindication but atopic individuals tend to react more.
- Antihistamines before/after contrast may be indicated.
- Food allergies (shellfish) = now proven to be wrong
- eGFR>30 relatively safe for contrast.
In which instances would you consider a serum creatinine to be ordered prior to IV contrast use? (9)
At what eGFR is the patient at risk of contrast induced nephropathy?
What are Ultrasounds?
7 Indications?
Ultrasound
- The use of ultrasound waves to evaluate structures.
- Widely used due to safety = no radiation
- Can be used for most areas of the body except bone and air filled structures.
- BUT - operator and patient dependent.
In which 3 structures/organs is an ultrasound superior to a CT?
- Pelvis
- Thyroid
- Testes
Ultrasound = first line of investigation for suspected appendicitis – especially in paediatric & thin patients
When are obstetric ultrasounds performed?
What is Magnetic Resonance Imaging? 3 Components?
3 Components to MRI: Magnet, Gradients, Coils.
9 MRI Contraindications?
Some cardiac pacemakers are MRI compatible – but most aren’t and you need the company to come out and confirm it and turn it off etc.
A patient comes to you with symptoms that will be well investigated by a CT scan of the head which should not be delayed. However, the patient then advises that she is pregnant. In view of the risk to the foetus should you:
= Request the CT scan but advise the radiologist that the patient is pregnant.
Foetal dose from a head scan is extremely small and could be somewhat reduced by shielding the abdomen. Hence there is negligible risk to the foetus. However the radiologist should be warned so that appropriate precautions can be taken.
A 15 year old male patient needs either a CT or an MRI scan both of which will be equally valuable in diagnosis. Both are equally available to you. The former costs less than the MRI however it delivers a significant radiation dose. Should you:
= Request the MRI scan despite the expense
Assuming the linear hypothesis, what is the approximate risk of inducing cancer from a single abdominal plain x-ray?
= 1 in 40,000
What is the average dose of natural background radiation (mSv) that a person Is exposed to each year in Australia during the course of one year?
= 1.5mSv
What is the approximate effective dose from a chest x-ray?
??
Tick which of the following imaging modalities deliver a dose of ionizing radiation.
- Plain xray
- Fluoroscoy
- PET scanning
- Nuclear medicine studies
- CT
A patient who has received a very large number of CT scans and other radiation procedures, comes with symptoms that you believe can only be properly investigated by another CT scan of abdomen and pelvis. However, you know that this is a high dose scan. In view of the previous high radiation dose received by this patient do you:
= Carry on with the CT scan as normal
A patient comes to you demanding a CT scan of the abdomen. You assess that this is not the appropriate investigation and that it is unlikely to provide any valuable information. It is likely that if you refuse the patient will go to another doctor. In view of this do you:
= Politely advise the patient that a CT scan has a finite risk associated with it and that this is not the appropriate investigation
Assuming the linear hypothesis, what is the approximate risk of inducing cancer from a single CT scan of the abdomen?
= 1 in 3,000
A 55 year old man presents to his GP with low back pain of recent onset. There is no radiation of the pain and no neurological symptoms. The pain is constant and keeps him awake at night. There is no positional component. He drinks occasional alcohol but is a smoker - one pack per day since his 20’s. On examination there is local tenderness of mid-lumbar spine, but otherwise no abnormality. Which two imaging procedures are recommended as the first-line examinations?
= Plain CXR & lumbar spine xray
The patient has ‘red flags’ (age, continuous nature of the pain, without positional component, heavy smoker). Imaging is therefore indicated. It is reasonable to perform plain x-rays initially to look for possible metastatic tumour.
In a 6 year old child with hip pain with no history of trauma and no systemic symptoms, which two imaging methods are appropriate as first line examinations?
??
A 75 year old woman presents with shortness of breath and chest pain on deep inspiration. She has been immobilized for the past two weeks due to fracture of her left foot and ankle. You suspect a pulmonary embolism. Which two further tests are required?
= CT Pulmonary Angiogram and Chest X-ray
Given the history a clinical risk assessment (e.g. wells’ criteria) would indicate a high pre-test probability for pulmonary embolism and therefore the patient can proceed to CT pulmonary angiography. It is reasonable to perform plain Chest radiography to look for other pathology such as pneumothorax or pneumonia.
A 70 year old man presents with acute left iliac fossa pain, mild fever and raised white count. Which imaging is appropriate?
??
A 65 year old man presents with acute onset of thunderclap headache (? Subarachnoid haemorrhage). Which imaging would you perform?
= CT without IV contrast
CT gives 90% sensitivity for subarachnoid haemorrhage. Lumbar puncture should be performed at least 6 hours post onset of symptoms.
A 25 year old sexually active woman complains of acute right iliac fossa/pelvic pain. She has missed no periods and her beta HCG is negative. Clinical differential diagnosis is acute appendicitis or gynaecological cause of pain. Which imaging investigation would you perform?
= Ultrasound
Ultrasound will show acute appendicitis and gynaecological disease in a high percentage of patients especially when combined with transvaginal ultrasound. Better than CT for gynaecological disease.
What will a radiation dose of 2 Sv cause? What about 10 Sv?
What are the indications for Magnetic resonance imaging?
Absolute contraindications to MRI?
2 types of MRIs?
Which contrast agent is most commonly used with MRI? How does it work? 2 Complications?
6 Indications for Diagnostic radiology of thoracic organs?
2 Indications for Diagnostic radiology of abdominal organs?
3 Indications for Diagnostic radiology of bony structures?
1 Indication for Diagnostic radiology of breasts?
3 Indications for Diagnostic radiology of the urinary system?
2 Indications for Diagnostic radiology to visualise blood vessels?
What are the contraindications to xrays?
Complications of Xrays?
- Deterministic effects?
- Stochastic effects?
What are the Effects of low dose ionising radiation? What is the average risk?
What are the only known effects of low dose radiation?
Subsequent induction of cancer and genetic defects
What is the approximate risk of getting cancer from exposure to ionising radiation?
5% per Sv
Which radiological procedures use ionising radiation?
What are the typical doses and associated risks of cancer of different radiological procedures?
What are the Limits on radiation dose for:
- Members of general public?
- Radiation workers?
- Patients?
Which of the following has no influence on the risk associated with any particular ionising radiation exposure?
The number of previous ionising radiation procedures experienced.
Why do we need Diagnostic Imaging Guidelines?
Up to one third of radiological examinations are totally or partially inappropriate.
Give 3 examples of Inappropriate imaging?
eg. Choosing to perform a CT to look for gallstones when the imaging modality of choice for that is ultrasound
Why do inappropriate tests matter?
What are Confidence Intervals?
= A probability that a parameter will fall between a set of values.
What is sensitivity in relation to test interpretation? Medical example?
- Sensitivity is the proportion of people WITH Disease X that have a POSITIVE blood test. A test that is 100% sensitive means all diseased individuals are correctly identified as diseased i.e. there are no false negatives. Importantly, as the calculation involves all patients with the disease, it is not affected by the prevalence of the disease.
- A sensitive test is used for excluding a disease, as it rarely misclassifies those WITH a disease as being healthy. An example of a highly sensitive test is D-dimer (measured using a blood test). In patients with a low pre-test probability, a negative D-dimer test can accurately exclude a thrombus (blood clot).
What is specificity in relation to test interpretation? Medical example?
- Specificity is the proportion of people WITHOUT Disease X that have a NEGATIVE blood test. A test that is 100% specific means all healthy individuals are correctly identified as healthy, i.e. there are no false positives.
- A specific test is used for ruling in a disease, as it rarely misclassifies those WITHOUT a disease as being sick. A perfectly specific test therefore means no healthy individuals are identified as diseased.
What is reliability in relation to test interpretation?
What are 4 Types of Reliability Estimates?
What is validity in relation to test interpretation? What are 3 types of validity?
Test validity is the extent to which a test (such as a chemical, physical, or scholastic test) accurately measures what it is supposed to measure.
What is the difference between reliability and validity in relation to test interpretation?
What is a receiver operating curve?
The receiver operating characteristic (ROC) curve, which is defined as a plot of test sensitivity as the y coordinate versus its 1-specificity or false positive rate (FPR) as the x coordinate, is an effective method of evaluating the quality or performance of diagnostic tests, and is widely used in radiology to evaluate the performance of many radiological tests.
What is this?
= Herbeden’s nodes
Heberden’s nodes are small, pea-sized bony growths that occur on the joint closest to the tip of the finger, also called the distal interphalangeal joint. Heberden’s nodes are a symptom of osteoarthritis (OA) of the hand.
A patient with a headache presents with this rash, what is the diagnosis?
= Meningitis
