Nephrology

Question 1

A 70-year-old woman develops confusion and drowsiness on the orthopaedic ward 24 hours after undergoing a left-sided hemiarthroplasty. On examination, the surgical wound site looks clean with no evidence of haematoma. There is no peripheral or sacral oedema, her chest is clear and she has a soft, non-tender abdomen with a non-distended bladder.

Her temperature is 37.1ºC, heart rate 80 /min, respiratory rate 20/min, BP 115/85 mmHg, and oxygen saturations 97% breathing air. Her urine output has been 0.3 ml/kg/hr over the last 8 hours.

What is the most appropriate initial management?

Answer 1

Administer 500 ml 0.9% sodium chloride over 15 minutes

If a patient has a urine output of < 0.5ml/kg/hr postoperatively the first step is to consider a fluid challenge, if there are no contraindications or signs of haemorrhage etc

Administering 500 ml 0.9% sodium chloride over 15 minutes is the correct answer. A urine output <0.5 ml/kg/hr for more than 6 hours meets the criteria for stage 1 acute kidney injury (AKI). The most important initial management is therefore restoring renal perfusion. In the absence of contraindications such as fluid overload or signs of haemorrhage, a 500 ml bolus of Hartmann’s solution or 0.9% sodium chloride with regular monitoring is an appropriate initial step in management. If clinical suspicion is high, further blood-work including blood cultures and IV antibiotics might be indicated too as part of the sepsis pathway.

Question 2

Giving 40 mg IV furosemide

Answer 2

The use of loop diuretics to artificially boost urine output is an inappropriate way to treat reduced urine output and fails to address the underlying cause. Furosemide would worsen pre-existing hypovolaemia and further compromise renal perfusion.

Question 3

Removing and replacing her urinary catheter

Answer 3

Even using appropriate aseptic technique, changing a catheter unnecessarily introduces infection risk in an already vulnerable hospital patient. With a non-distended bladder and no mentioned signs of symptomatic urinary tract infection or catheter blockage such as blood, debris or foul-smelling cloudy urine in the catheter bag, we can assume that there is no indication to remove the catheter at this point.

Question 4

What is the appropriate type of diuretic to help prevent reaccumulation of ascites?

Answer 4

Aldosterone antagonist

Ascites - use spironolactone

Aldosterone antagonists such as spironolactone are used in high doses to help prevent the formation of ascites in patients with chronic liver disease. A loop diuretic may need to be added in patients who don’t respond

Question 5

Shifting dullness is noted. The gastroenterologist plans to start him on medication for this finding. What is the most appropriate management for this patient?

Answer 5

Ascites - use spironolactone

Shifting dullness is noted in ascites

Spironolactone is a potassium-sparing diuretic that is the recommended first-line therapy for managing ascites in patients with liver cirrhosis. Spironolactone works by antagonising the effects of aldosterone, which promotes sodium and water retention. Spironolactone can be used in combination with loop diuretics, such as furosemide, to enhance diuresis and prevent hypokalemia. The recommended starting dose of spironolactone is 100 mg/day. This patient’s blood tests show hypoalbuminaemia (consistent with poor liver synthetic function) and a high bilirubin (due to cirrhosis causing impaired bilirubin metabolism in the liver).

Question 6

Furosemide

Answer 6

is a loop diuretic that can be used in combination with spironolactone to manage ascites, but it is not recommended as first-line therapy.

Furosemide alone can cause hypokalemia, which may exacerbate hepatic encephalopathy in patients with liver cirrhosis. Furosemide can also worsen renal function, which is already impaired in patients with liver cirrhosis.

Question 7

Lactulose

Answer 7

is a laxative that is used in the management of hepatic encephalopathy (HE). It is a non-absorbable sugar which can be given orally or rectally. It is not used in the management of ascites.

The purpose of its use in hepatic encephalopathy is to help reduce toxins that can accumulate in hepatic failure as well as reduce the bacterial burden in the GI tract which can produce ammonia in the bowel leading to encephalopathy.

Question 8

Metolazone

Answer 8

is a thiazide-like diuretic that is not recommended for the management of ascites in patients with liver cirrhosis. Thiazide diuretics are less effective in patients with impaired renal function, which is common in patients with cirrhosis.

Metolazone can also cause electrolyte imbalances, including hypokalemia, hyponatremia, and hypomagnesemia, which may exacerbate the complications of cirrhosis.

Question 9

Rifaximin

Answer 9

is a broad-spectrum antibiotic that is used in the management of hepatic encephalopathy (HE) and traveller’s diarrhoea. In HE, rifaximin reduces the GI bacterial burden of ammonia-producing bacteria. Additionally, rifaximin mitigates ascites and improves the survival of cirrhotic patients with refractory ascites. It is believed to have these effects by reducing systemic inflammation through its effect on the GI bacterial burden, as mentioned above. However, it is not used as a first-line treatment in the management of ascites and other options should be exhausted first.

Question 10

A 5-year-old child presents with bloody diarrhoea, fatigue, and decreased urine output after a recent episode of gastroenteritis. Blood tests show the following: Considering the likely diagnosis, what organism is most likely responsible?

Answer 10

Haemolytic uraemic syndrome - classically caused by E coli 0157:H7

This patient presents with the classic symptoms of haemolytic uraemic syndrome (HUS). HUS typically presents in children with a triad of acute kidney injury, microangiopathic haemolytic anaemia and thrombocytopenia. E. coli 0157:H7 is the most common cause of HUS, as it produces Shiga-like toxins. This causes bloody diarrhoea, as in this scenario. These toxins damage endothelial cells, which leads to microthrombi formation, causing mechanical destruction of red blood cells (resulting in haemolysis and anaemia) and consumption of platelets (leading to thrombocytopenia).

Question 11

Campylobacter jejuni

Answer 11

This is a common cause of bacterial gastroenteritis but does not typically cause HUS.

Question 12

Clostridium difficile

Answer 12

This causes antibiotic-associated diarrhoea and colitis but is not linked to HUS. Diarrhoea is usually watery, rather than bloody, in Clostridium difficile infection.

Question 13

Salmonella typhi

Answer 13

Salmonella typhi causes typhoid fever, associated with ‘rose spots’ secondary to bacterial emboli to the skin, prolonged fever and gastrointestinal symptoms. Typhoid fever does not cause HUS.

Question 14

Shigella dysenteriae

Answer 14

This can produce Shiga toxin and may rarely cause HUS, but it is a much less common cause compared to E. coli 0157:H7.

Question 15

A 71 year old woman has a 7 day history of vomiting and diarrhoea. Renal function was noted to be normal on routine blood tests one month ago. Which of the following is most consistent with a diagnosis of acute tubular necrosis?

Answer 15

Raised urinary sodium

Question 16

This patient has acute kidney injury. The causes can be divided as follows:

Answer 16

Pre-renal:
Caused by inadequate renal perfusion e.g. dehydration, haemorrhage, heart failure, sepsis
Kidneys act to concentrate urine and retain sodium - urine osmolality high, urine sodium low

Renal:
Most common = acute tubular necrosis
Damage to tubular cells due to prolonged ischaemia or toxins
Kidneys can no longer concentrate urine or retain sodium - urine osmolality low, urine sodium high
Rarer causes = acute glomerulonephritis, acute interstitial nephritis

Post-renal:
Obstruction of urinary tract
Usually identified with hydronephrosis on renal ultrasound

Question 17

AKI is staged according to the serum creatinine changes, and/or the production of urine.

Answer 17

Stage 1 Increase 1.5-1.9x baseline < 0.5ml/kg/h for >6 consecutive hours

Stage 2 Increase 2.0-2.9x baseline < 0.5ml/kg/h for >12 consecutive hours

Stage 3 Increase > 3x baseline or >354 µmol/L < 0.3ml/kg/h for > 24h or anuric for 12h

Question 18

A 70-year-old man has been admitted with abdominal pain. The surgeons wish to perform a contrast-enhanced CT but are concerned because he has chronic kidney disease stage 3. His latest renal function is shown below:

Na + 142 mmol/l
K+ 4.6 mmol/l
Urea 8.1 mmol/l
Creatinine 130 µmol/l

Which one of the following is the most important step in reducing the risk of contrast-induced nephropathy?

Answer 18

Intravenous 0.9% sodium chloride pre- and post-procedure

Prevention of contrast-induced nephropathy: volume expansion with 0.9% saline

Question 19

NICE recognise any of the following criteria to diagnose AKI in adults:

Answer 19

↑ creatinine > 26µmol/L in 48 hours
↑ creatinine > 50% in 7 days
↓ urine output < 0.5ml/kg/hr for more than 6 hours

Question 20

A 41-year-old woman is discharged from hospital following a diagnosis of community-acquired pneumonia, to be managed at home on amoxicillin. A day later she returns to the emergency department with a low-grade fever, widespread erythematous rash and pain throughout her joints and lower back, with her initial bloods showing a significantly elevated creatinine.

Which of the following urine findings would support the most likely diagnosis?

Answer 20

Raised urinary white cells and eosinophils

Acute interstitial nephritis causes an ‘allergic’ type picture consisting usually of raised urinary WCC and eosinophils, alongside impaired renal function

The clinical picture points to a diagnosis of acute interstitial nephritis, secondary to the amoxicillin. Penicillins are some of the most common causes of drug-induced interstitial nephritis, so it is always important to look out for any new drugs with any presentation of new-onset renal impairment.

Acute interstitial nephritis essential causes an ‘allergy’-type reaction, so look out for urticarial-like rashes and a fever. Arthralgia is also a common feature. Classically urine shows elevated white cell counts and eosinophils. IgE is also often elevated.

Question 21

A 6-year-old boy is diagnosed as having nephrotic syndrome. A presumptive diagnosis of minimal change glomerulonephritis is made. What is the most appropriate treatment?

Answer 21

Prednisolone

A renal biopsy is only indicated if response to steroids is poor

Question 22

Azathioprine

Answer 22

is an immunosuppressive drug used to treat autoimmune hepatitis. This would present with signs of chronic liver disease, but in this case, the patient has already been diagnosed with secondary cirrhosis due to alcohol excess

Question 23

Ciprofloxacin

Answer 23

can be prescribed following an episode of spontaneous ascites in patients with chronic liver conditions, but the NICE guidelines indicate that the prescription is indicated only if the patient has an ascitic protein of 15 g/litre or less. In this case, the patient has 17g/l of fluid protein,

Question 24

Prednisolone

Answer 24

is used to treat cases of acute liver failure. This condition would present with a much more acute picture than this one.

Question 25

Terlipressin

Answer 25

is used to treat hepatorenal syndrome, a disease with unknown aetiology that is associated with vasodilation. Vasopressin analogues work by causing vasoconstriction of the splanchnic circulation.

Question 26

minimal change glomerulonephritis first-line treatment option?

Answer 26

Prednisolone

minimal change glomerulonephritis: patient has presented with facial oedema associated with hypoalbuminemia and proteinuria.

Question 27

The risk of which one of the following cancers is he most at risk of following renal transplantation?

Answer 27

Squamous cell carcinoma of the skin

Question 28

CKD stage

Answer 28

CKD stage 1 can only be diagnosed if there is an eGFR >90 AND markers of kidney damage such as proteinuria or electrolyte disturbances.

CKD stage 2 can only be diagnosed if there is an eGFR 60-90 AND markers of kidney damage such as proteinuria or electrolyte disturbances. Remember CKD stage 1 and 2 requires markers of kidney damage for a diagnosis.

CKD stage 3a can only be diagnosed if there is an eGFR of 45-59 with or without markers of kidney damage.

CKD stage 3b can only be diagnosed if there is an eGFR of 30-44 with or without markers of kidney damage.

Question 29

A 14 year-old boy develops visible haematuria following an upper respiratory tract infection.

Answer 29

IgA nephropathy is also called Berger’s disease.

Question 30

Features of renal cell carcinoma:

Answer 30

classical triad: haematuria, loin pain, abdominal mass
pyrexia of unknown origin
left varicocele (due to occlusion of left testicular vein)
endocrine effects: may secrete erythropoietin (polycythaemia), parathyroid hormone (hypercalcaemia), renin, ACTH
25% have metastases at presentation

Question 31

A 21-year-old female complains of dysuria for the past week, despite just completing a three day course of trimethoprim. Urine dipstick is positive for blood + and leucocytes +. A MSSU shows no organism.

Answer 31

Features of Chlamydia

asymptomatic in around 70% of women and 50% of men
women: cervicitis (discharge, bleeding), dysuria
men: urethral discharge, dysuria

Question 32

This patient has new-onset haematuria following a recent upper respiratory tract infection?

Answer 32

IgA nephropathy (also known as Berger’s disease) classically presents as visible haematuria following a recent URTI

post-streptococcal glomerulonephritis that presents following 2 weeks from an upper or lower respiratory tract infection.

Question 33

Focal segmental glomerulosclerosis

Answer 33

This is a cause of nephrotic syndrome seen in children and adults. Unlike haematuria, as seen in this patient, proteinuria is a predominant feature in focal segmental glomerulosclerosis

Question 34

Minimal change disease

Answer 34

Although it is a common renal disease that affects children and young adults, the trace protein levels and high blood levels on urinalysis do not fit with the diagnosis (that typically presents with profound proteinuria, hypoalbuminemia, and oedema such as facial swelling).

Question 35

Post-streptococcal glomerulonephritis

Answer 35

This is a very reasonable differential diagnosis given the history of haematuria following a recent respiratory tract infection. However, unlike this patient’s presentation, those with post-streptococcal glomerulonephritis develop haematuria approximately 2 weeks following an acute infection.

Question 36

A 33-year-old pregnant woman presents for advice. She is known to have polycystic kidney disease but is currently well. Her father also has polycystic kidneys and is on dialysis . What is the chance her child will also have the disease?

Answer 36

50%

Polycystic kidney disease is usually inherited in an autosomal dominant fashion and hence 50% of her children will be affected, regardless of gender. The autosomal recessive form is rare and usually causes death in childhood.

Question 37

A 5-year-old girl is brought to the Emergency Department by her parents. She has been unwell for 5 days with diarrhoea and is now lethargic and pale. She has not passed urine in over 14 hours, despite her fluid intake being good.

The child is normally well with no past medical history. She takes no regular medications and has had all of her vaccinations. Her symptoms started 2 days after she ate a chicken burger at a carnival.

On examination, multiple petechiae are noted on her torso and limbs and her feet are oedematous.

Given the likely diagnosis, what is the causative organism of this patient’s illness?

Answer 37

Escherichia coli

Normocytic anaemia, thrombocytopaenia and AKI following diarrhoeal illness - consider HUS

This child has had a diarrhoeal illness, likely related to eating undercooked meat at a carnival, and now presents unwell with several abnormal examination findings. Whilst poor urine output could be related to dehydration, the stem is clear that the child has been taking in good amounts of fluid. The oliguria, coupled with peripheral oedema, suggests an underlying acute kidney injury. The petechial bruising and pallor suggest haematological abnormalities. Overall, this picture is in keeping with haemolytic uraemic syndrome (HUS). HUS is characterised by a triad of normocytic anaemia, thrombocytopenia and acute kidney injury. Most cases occur in children and most are associated with diarrhoeal illnesses. The most common cause is Shiga-toxin producing Escherichia coli, particularly the O157:H7 strain. Uncooked meat - such as a chicken burger from a carnival - is a common source of Escherichia coli infection.

Question 38

Campylobacter jejuni

Answer 38

is a leading cause of acute diarrhoea, with approximately one quarter of cases involving bloody diarrhoea. Raw or undercooked meat - particularly chicken - is a common source. However, the illness is usually mild, and not in itself associated with anaemia, renal failure or thrombocytopenia. Whilst there are causes of Campylobacter jejuni associated HUS, which would explain the examination findings seen in this patient, it is a very rare cause of HUS and certainly not the most likely differential in this case.

Question 39

Clostridium perfringens

Answer 39

is another common cause of food-borne illness and causes acute diarrhoea and vomiting. It is not associated with HUS. Whilst vomiting and diarrhoea alone could cause an acute kidney injury alone, this would be related to hypovolaemia (which is unlikely in this child who has been receiving lots of fluid). Furthermore, it would not cause signs of anaemia or thrombocytopenia

Question 40

Salmonella

Answer 40

species cause diarrhoeal illnesses (although usually not with bloody diarrhoea) after ingestion of contaminated food. Whilst they can be implicated in the development of HUS,

Question 41

Shigella

Answer 41

species cause diarrhoeal illnesses (which can involve bloody diarrhoea) after ingestion of contaminated food (including undercooked meat) and water. Infection is typically mild; As above, the findings consistent with anaemia, thrombocytopenia and acute renal failure both suggest HUS, rather than simple infection alone. Whilst some Shigella species can produce toxins causing HUS, this is a far less common cause of HUS than Escherichia coli and hence is not the most likely causative organism in this patient.

Question 42

A 32-year-old woman presents to the emergency department with persistent diarrhoea after eating some undercooked chicken three days previously. On questioning, she has not been vomiting but has some mild abdominal pain. She has not noticed any blood or mucus in their stool. An arterial blood gas is taken as part of their investigations.

What is the most likely disorder of acid-base balance seen on arterial blood gas?

Answer 42

Normal anion gap metabolic acidosis.

This woman has increased gastrointestinal loss of bicarbonate from prolonged diarrhoea. The increased loss of bicarbonate results in the loss of alkalotic ions, leaving the blood in an acidotic state. This is a metabolic acidosis as carbon dioxide plays no role in the pH state. It is a normal anion gap as acidosis is not a result of acidotic ion production, such as lactate, ketosis, or salicylate acid.

Question 43

A 68-year-old man presents with visible haematuria for the past two weeks. There is no history of pain. MSSU confirms haematuria but fails to show any organism.

Answer 43

Transitional cell carcinoma of the bladder

Question 44

A 3-year-old girl is brought to surgery as her parents have noticed blood in her urine. Examinations reveals a loin mass. MSU shows no evidence of a urinary tract infection. The only relevant family history is her grandmother who has chronic kidney disease.

Answer 44

Wilms’ nephroblastoma is one of the most common childhood malignancies. It typically presents in children under 5 years of age, with a median age of 3 years old.

Features
abdominal mass (most common presenting feature)
flank pain
painless haematuria
other features: anorexia, fever
unilateral in 95% of cases
metastases are found in 20% of patients (most commonly lung)

Question 45

A 57-year-old man presents with left sided abdominal pain radiating to his scrotum. The pain is severe and not controlled by a combination of paracetamol and ibuprofen. Urine dipstick shows: blood++, protein+, leucocytes++, nitrites negative. Clinical examination is unremarkable.

Answer 45

Renal stones

Question 46

A 55-year-old man with a history of type 2 diabetes mellitus presents for a routine review. On examination, he appears well and there are no abnormal examination findings except for his blood pressure, which is recorded at 160/110 mmHg. Routine blood tests are performed which demonstrate the following:

Na+ 139 mmol/L (135 - 145)
K+ 4.5 mmol/L (3.5 - 5.0)
Urea 16 mmol/L (2.0 - 7.0)
Creatinine 163 µmol/L (55 - 120)

What additional feature would suggest that the cause of this presentation is chronic and not acute?

Answer 46

Hypocalcaemia

Hypocalcaemia is an indication that kidney disease is chronic and not acute

This patient has blood tests suggestive of renal impairment, as shown by the increased urea and creatinine, which may be due to his history of type 2 diabetes mellitus (which can cause diabetic nephropathy). It is important to establish whether the renal impairment is acute or chronic, as their management varies significantly. Chronic renal failure can lead to impaired conversion of 25-hydroxyvitamin D to its active form, which is needed for intestinal calcium absorption. This makes hypocalcaemia a marker that suggests the kidney disease is chronic and not acute, as an acute kidney injury is not associated with hypocalcaemia.

Answer 47

Hypocalcaemia

An elderly patient with a raised CK after a long lie should also have their urine checked for myoglobins, and their blood checked for calcium and phosphate

This patient has a likely diagnosis of rhabdomyolysis given the patient’s presentation of a fall with a probable long lie since there is a prolonged interval when the patient was last seen well. Other factors supporting the diagnosis include the raised creatine kinase and hypothermia. Patients with rhabdomyolysis should have a bone profile taken to measure calcium and phosphate. Calcium typically binds to myoglobin released from damaged muscle tissue causing serum hypocalcaemia.

Question 48

A 45-year-old man presents to the emergency department with confusion. He has a history of chronic alcohol use. On examination, his respiratory rate is 30 breaths per minute. His blood test results are as follows:

Sodium 140 mmol/L (135 - 145)
Potassium 4.0 mmol/L (3.5 - 5.0)
Chloride 98 mmol/L (98 - 107)
Bicarbonate 12 mmol/L (22 - 29)
Urea 5.0 mmol/L (2.0 - 7.0)
Creatinine 90 µmol/L (55 - 120)
Calcium 2.3 mmol/L (2.1 - 2.6)
Phosphate 1.1 mmol/L (0.8 - 1.4)
Magnesium 0.9 mmol/L (0.7 - 1.0)

What is the patient’s anion gap?

Answer 48

34 mmol/L

Anion gap = (sodium + potassium) - (bicarbonate + chloride)

144 - 110= 34

This elevated anion gap indicates a high anion gap metabolic acidosis. The patient’s history of chronic alcohol use, along with confusion and an elevated respiratory rate (30 breaths per minute), suggests alcohol-related ketoacidosis (AKA). In alcohol-related ketoacidosis, patients often present with vomiting, abdominal pain, and ketosis, and the metabolic acidosis is due to the accumulation of organic acids. The elevated respiratory rate in this patient likely represents Kussmaul’s breathing, a form of respiratory compensation for severe metabolic acidosis.

Question 49

An 80-year-old gentleman is brought in to the emergency department by ambulance after being found unresponsive in his care home. His care home records show he had recently been given a course of doxycycline for an unknown reason.

On initial assessment, his airway is patent but he is tachypnoeic with a respiratory rate of 40 breaths/min. His saturations are 96% on 4L/min of oxygen and he has bibasal crackles. His heart rate is 96beats/min and his blood pressure is 82/44mmHg. His blood glucose is 4.1mmol/L, his temperature 38.9ºC and his Glasgow Coma Scale (GCS) is 9 (E3M4V2).

He is given a fluid bolus and an arterial blood gas (ABG) on 4L/min of oxygen is taken:

pH 7.18 (7.35 - 7.45)
pO2 11 kPa (10 -14)
pCO2 3.2 kPa (4.5 - 6)
Base excess (BE) -9 mmol/L (-2 - +2)
Bicarbonate (HCO3) 18 mmol/L (22 - 26)
Lactate 9 mmol/L (0.6 - 1.4)

What is the most likely cause of the abnormal pH?

Answer 49

Lactic acidosis

Sepsis can cause a profound lactic acidosis

The bibasal crackles suggest a lower respiratory tract infection. When considered alongside the low GCS, fever and hypotension, this gentleman has sepsis from his lower-respiratory tract infection. Sepsis can cause a profound lactic acidosis as seen on this ABG.

Question 50

A 20-year-old man presents with facial and ankle swelling. This has slowly been developing over the past week. During the review of systems he describes passing ‘frothy’ urine. A urine dipstick shows protein +++. A diagnosis of nephrotic syndrome is later confirmed following a 24-hour urine sample. What is the most likely cause of this presentation?

Answer 50

Minimal change disease

Nephrotic syndrome in children / young adults - minimal change disease

Minimal change glomerulonephritis nearly always presents as nephrotic syndrome, accounting for 75% of cases in children and 25% in adults. The majority of cases are idiopathic and respond well to steroids.

Question 51

A 55-year-old lady is found in cardiac arrest with the following blood result:

Sodium 130mmol/l (135-145)
Potassium 7.3mmol/l (3.5-5.0)
Urea 9.1mmol/l (2.5-7.0)
Creatinine 167mmol/l (60-110)

She is initially given IV calcium gluconate.

What does this medication do to the electrolyte levels?

Answer 51

No change

Hyperkalaemia + ECG changes: IV calcium gluconate is given for stabilisation of the cardiac membrane

Initially the calcium gluconate is given to stabilise the membrane so the level of potassium doesn’t increase.

It is the combination of insulin and dextrose or the use of nebulised salbutamol that causes the removal of potassium from the extracellular space to the intracellular space.

Potassium is then excreted from the body via calcium resonium.

Question 52

A 15-year-old girl presents with a palpable purpuric rash over her lower limbs accompanied by polyarthralgia following a recent sore throat. What is the most likely diagnosis?

Answer 52

Henoch-Schonlein purpura

Henoch-Schonlein purpura classically presents with abdominal pain, arthritis, haematuria and a purpuric rash over the buttocks and extensor surfaces of arms and legs

also known as IgA vasculitis, is a small vessel vasculitis characterised by palpable purpura, arthritis or arthralgia, abdominal pain and renal involvement. It often follows an upper respiratory tract infection and is most common in children. The palpable purpuric rash typically affects the lower limbs and buttocks.

also known as IgA vasculitis, is a small vessel vasculitis characterised by palpable purpura, arthritis or arthralgia, abdominal pain and renal involvement. It often follows an upper respiratory tract infection and is most common in children. The palpable purpuric rash typically affects the lower limbs and buttocks.

Question 53

Rubella

Answer 53

presents with a pinkish-red maculopapular rash that starts on the face and spreads downwards. Other symptoms include fever, lymphadenopathy, and joint pains particularly in adult women. However, it does not present with a palpable purpuric rash.

Question 54

Measles

Answer 54

Measles is characterised by a prodromal phase of high fever, malaise, conjunctivitis, coryza and Koplik’s spots followed by a generalised maculopapular rash which spreads from head to toe over 3 days. The rash isn’t typically described as palpable or purpuric.

Question 55

Erythema multiforme

Answer 55

This condition usually presents with target lesions (a red centre surrounded by a pale ring and then a red outer ring) following herpes simplex virus (HSV) infection or drug exposure. It does not typically present with polyarthralgia or follow an upper respiratory tract infection.

Question 56

A 45-year-old man undergoes a renal transplant from a deceased donor due to renal failure. The on-call doctor is asked to review the patient 2 hours after the procedure. His observations show temperature of 40ºC, heart rate 114/min, respiratory rate 23/min, saturations of 97% in room air, blood pressure of 81/62mmHg.

Considering the most likely diagnosis, what is the appropriate management for this patient?

Answer 56

Removal of the transplant

No treatment is possible for hyperacute transplant rejection - the graft must be removed.

Removal of the transplanted kidney is the appropriate management for hyperacute rejection. In hyperacute rejection, there is pre-existing antibody-mediated damage to the transplanted organ, and no treatment is possible. The graft must be removed immediately to prevent further damage.

Question 57

A patient with sepsis is being treated in hospital. Initially, two 500ml boluses of 0.9% sodium chloride are required to raise his systolic blood pressure (BP) above 90mmHg. Once the BP is in range the foundation doctor prescribes sodium chloride 0.9% maintenance fluids at 1L every 8 hours.

Which of the following complications is most likely to occur as a result of the choice of fluid administered to this patient?

Answer 57

Hyperchloraemic metabolic acidosis

Use of 0.9% Sodium Chloride for fluid therapy in patients requiring large volumes = risk of hyperchloraemic metabolic acidosis

This patient has received 0.9% sodium chloride. Hyperchloraemic metabolic acidosis is a known iatrogenic complication of using 0.9% sodium chloride in large volumes. In the event of hyperchloraemia or acidaemia, monitor chloride levels daily. If resuscitation is required Hartmanns can be used instead. If the patient now only requires maintenance fluids NICE recommends considering 25-30 ml/kg/day sodium chloride 0.18% in 4% glucose (with potassium supplement as required). See compositions of commonly used crystalloids for further information: https://www.nice.org.uk/guidance/cg174/resources/composition-of-commonly-used-crystalloids-table-191662813)

Question 58

Central pontine myelinolysis

Answer 58

is a complication of correcting hyponatraemia too rapidly

Question 59

Lactic acidosis

Answer 59

A drug classically associated with lactic acidosis is metformin.

Question 60

Hypochloraemic hypokalaemic metabolic alkalosis

Answer 60

is commonly seen in children with pyloric stenosis

Question 61

A 25-year-old woman with a history of end-stage renal disease secondary to focal segmental glomerulosclerosis presents to the Emergency Department. For the past 12 months she has used Continuous Ambulatory Peritoneal Dialysis (CAPD). She feels generally unwell with abdominal pain and a fever. She also describes her last bag as being ‘cloudy’. Which organism is most likely to be responsible for this presentation?

Answer 61

Staphylococcus epidermidis

Coagulase-negative Staphylococcus is the most common cause of peritonitis secondary to peritoneal dialysis

This patient is presenting with signs and symptoms of peritonitis, a known complication of Continuous Ambulatory Peritoneal Dialysis (CAPD). In CAPD-related peritonitis, the most common causative organism is coagulase-negative staphylococci, which includes Staphylococcus epidermidis. These organisms are part of the normal skin flora and can be introduced into the peritoneal cavity during the process of connecting or disconnecting dialysis bags.

Question 62

A 50 year-old man with dialysis dependent chronic kidney disease is awaiting renal transplant. He complains of fatigue. On examination you note heart rate 95 beats per minute, soft ejection systolic murmur that doesn’t radiate and pallor. There were no other abnormal features.

What is the most likely cause of his fatigue?

Answer 62

Anaemia

Anaemia is extremely common in chronic kidney disease. It is often caused by iron deficiency or erythropoietin deficiency. The man in this case has a few signs and symptoms of anaemia - tachycardia, fatigue, pallor and an aortic flow murmur.

Question 63

hyperkalaemic What is the most appropriate initial management?

Answer 63

Intravenous calcium gluconate

This patient is hyperkalaemic and has associated ECG changes (peaked T waves in the anterior leads and bradycardia). Bradycardia in such patients is a worrying sign as asystole may occur. The first priority in this patient is to stabilise the myocardium with intravenous calcium gluconate.

Question 64

A 12-year-old boy presents in acute renal failure. Last week he had a bad episode of bloody diarrhoea but this has now passed. A diagnosis of haemolytic-uraemic syndrome is made.

Hb 100 g/l
Platelets 110 * 109/l
WBC 10 * 109/l

Which of the following is the best treatment for this condition?

Answer 64

Only supportive treatment e.g. fluids and dialysis as required.

There is no role for antibiotics in the treatment of haemolytic uraemic syndrome unless indicted my preceding diarrhoeal infection.

This question is about a boy presenting with haemolytic-uraemic syndrome following diarrhoeal infection and is asking for the appropriate treatment. In most cases of haemolytic-uraemic syndrome, the mainstay of treatment is supportive, with fluids, blood transfusions and dialysis as required.

Question 65

A 63-year-old man attends for a GP appointment and states that he has had two episodes of visible blood in his urine. One episode occurred last week and the other this morning. There was not any pain. He denies any lower urinary tract symptoms. A urinalysis shows +++ blood and is negative for all other markers. What investigation should be requested?

Answer 65

Cystoscopy

This patient has had two episodes of painless frank haematuria. According to NICE guidelines he warrants an urgent referral on the cancer pathway due to his age and due to his presentation. He is unlikely to have a urinary tract infection as his urinalysis is negative for leukocytes and nitrites and waiting for results of a urine culture should not delay referral for further investigations.

Gold standard for bladder cancer diagnosis is cystoscopy. The European Urology Association states that cystoscopy is recommended in all patient with symptoms suggestive of bladder cancer. It cannot be replaced by cytology or by any other non-invasive test.

Question 66

You are reviewing a 65-year-old in the renal clinic. He has been on haemodialysis for chronic kidney disease for the past 6 years. What is he most likely to die from?

Answer 66

CKD on haemodialysis - most likely cause of death is IHD

Patients with chronic kidney disease (CKD), especially those on haemodialysis, have a significantly higher risk of cardiovascular diseases. Among them, ischaemic heart disease represents the leading cause of death. This is due to several factors including hypertension, dyslipidaemia, anaemia and systemic inflammation that are common in CKD patients.

Question 67

A 68-year-old man with chronic kidney failure has been advised by his nephrologist that he needs to follow a ‘renal diet’. He comes to see you to learn more about this.

Which one of the following is usually advised to patients with chronic kidney disease?

Answer 67

Low potassium diet

Patients with chronic kidney disease (CKD) often have difficulty excreting potassium due to reduced kidney function. A build-up of potassium in the blood can lead to hyperkalemia, which can cause serious complications such as abnormal heart rhythms and even cardiac arrest. Therefore, it is important for patients with CKD to follow a low potassium diet to help maintain normal potassium levels.

Question 68

A 21-year-old woman presents to the emergency department with visible haematuria. On further questioning, she states that 10 days ago she had ‘tonsillitis’ which has resolved but she continues to feel very tired.

Her blood pressure is 182/72mmHg. Other observations are normal. Urine dip is positive for blood and protein.

What test would confirm the causative organism?

Answer 68

Anti-streptolysin O titre

This is a typical history of post-streptococcal glomerulonephritis; streptococcal throat infection 1-2 weeks ago followed by visible haematuria, malaise with hypertension, and a urine dip positive for blood and protein. Therefore, anti-streptolysin O titre is correct. This measures antibodies against streptolysin O, a substance produced by group A streptococcus bacteria.

Question 69

A 2-year-old boy is brought to his GP.

His father is concerned as he appears ‘puffy’. He is usually fit and well, but has picked up lots of colds at nursery recently.

On examination, the GP notes periorbital and ankle oedema. Heart sounds are normal, but on auscultation of the lungs, basal crackles are heard bilaterally.

Urinalysis reveals proteinuria, but no haematuria.

What is the most likely underlying condition?

Answer 69

Minimal change disease

Minimal change disease is the most common cause of nephrotic syndrome in a child

Minimal change disease is the most likely diagnosis. This child has clinical signs of nephrotic syndrome: oedema with proteinuria. The bi-basal lung crackles are suggestive of pulmonary oedema. The most common cause of glomerulonephritis in children is minimal change disease.

Question 70

A 46-year-old woman presents to the emergency department with a three-week history of persistent vomiting. Her past medical history includes severe peptic ulcer disease and well-controlled Cushing’s syndrome. She denies any haematemesis or melaena. The consultants suspect a pyloric outlet obstruction due to peptic ulcer disease.

In addition to a severe extracellular fluid volume deficit, what electrolyte disturbance is she likely to have?

Answer 70

Hypochloraemia, hypokalaemia and metabolic alkalosis

Diarrhoea can cause a normal anion gap acidosis whereas vomiting causes alkalosis

The correct answer is hypochloraemia, hypokalaemia, and metabolic alkalosis. She has been vomiting hydrochloric acid. This will create a metabolic alkalosis from hydrogen ion loss and hypochloraemia from loss of chloride. Hypokalaemia is a consequence of the process: dehydration and sodium loss stimulates the production of aldosterone via the renin-angiotensin-aldosterone system and therefore sodium is reabsorbed at the collecting duct in exchange for potassium, which is lost in the urine. Cushing’s syndrome is a distractor since it is well controlled.

Question 71

A 47-year-old male has been nil by mouth for 3 days awaiting bariatric surgery that has been repeatedly postponed, he is to be prescribed IV dextrose to ensure his glucose requirements are being met.

His weight is 150kg, which of the following is an acceptable daily amount of glucose for him to be given?

Answer 71

100g

When prescribing fluids, the glucose requirement is 50-100 g/day irrespective of the patient’s weight

Question 72

A 19-year-old man presents to his general practitioner with a 1-day history of visible blood in his urine. He denies abdominal pain or pain when passing urine. Other than a brief coryzal illness 4 days ago, there is no past medical history of note and he takes no regular medications.

His urine is analysed as follows:

Blood Positive
Protein Trace positive
Leucocytes Negative
Nitrites Negative
Glucose Negative

What is the most likely diagnosis?

Answer 72

IgA nephropathy

IgA nephropathy classically presents as visible haematuria following a recent URTI

IgA nephropathy is correct. This patient has new-onset haematuria following a recent upper respiratory tract infection. This is in keeping with a diagnosis of IgA nephropathy (also known as Berger’s disease), the most common cause of haematuria worldwide. The disease commonly presents in young males and the onset is typically very acute, in contrast to post-streptococcal glomerulonephritis that presents following 2 weeks from an upper or lower respiratory tract infection.

Question 73

A 58-year-old gentleman is admitted with a high stoma output from his ileostomy. He underwent a colectomy 10 years ago due to severe ulcerative colitis. He feels weak and complains of leg cramps. He reports intermittent episodes of palpitations. His abdomen is soft with slight generalised tenderness.

His bloods show:

Na+ 138 mmol/l
K+ 2.2 mmol/l
Urea 13.3 mmol/l
Creatinine 150 µmol/l

ECG shows flattened T waves and U waves. He is admitted to the medical admission unit.

How should his electrolyte derangement be managed?

Answer 73

Transfer to high care area with cardiac monitoring, 3 x 1litre bags of 0.9% saline with 40mmol KCL per bag over 24 hours.

This gentleman has severe hypokalaemia, defined as a serum potassium < 2.5mmol/l. Mild to moderate hypokalaemia can be asymptomatic but the more severe the electrolyte derangement the more likely that symptoms will develop. Symptoms include weakness, leg cramps, palpitations secondary to cardiac arrhythmias and ascending paralysis.

Causes can be secondary to:

1.) Increased potassium loss:
Drugs: thiazides, loop diuretics, laxatives, glucocorticoids, antibiotics
GI losses: diarrhoea, vomiting, ileostomy
Renal causes: dialysis
Endocrine disorders: hyperaldosteronism, Cushing’s syndrome

2.) Trans-cellular shift
Insulin/glucose therapy
Salbutamol
Theophylline
Metabolic alkalosis

3.) Decreased potassium intake

4.) Magnesium depletion (associated with increased potassium loss)

ECG changes seen in hypokalaemia include:
U waves
T wave flattening
ST segment changes

Treatment of hypokalaemia depends on severity. Any causative agents should be removed. Gradual replacement of potassium via the oral route is preferred if possible.

Mild to moderate hypokalaemia 2.5 - 3.4 mmol/l can be treated with oral potassium provided the patient is not symptomatic and there are no ECG changes.

Severe hypokalaemia (<2.5mmol/l) or symptomatic hypokalaemia should be managed with IV replacement. The patient should be managed in an area where cardiac monitoring can take place. If there are no contraindications to fluid therapy (e.g. volume overload, heart failure) potassium should be diluted to low concentrations as higher concentrations can be phlebitic. The infusion rate should not exceed 20mmol/hr. In this case, 3 bags of 0.9% Saline with 40mmol KCL is the correct answer.

Question 74

A 65-year-old male presents to an urgent care centre concerned that he is urinating less frequently. He reports urinating once in the past 10 hours and feels like he can’t urinate now (despite wanting to). He has a past medical history of diabetes mellitus which is managed with metformin and chronic back pain which is managed with ibuprofen with PPI cover. He has no known allergies. Bloods are taken which show:

Na+ 139 mmol/L (135 - 145)
K+ 4.8 mmol/L (3.5 - 5.0)
Bicarbonate 22 mmol/L (22 - 29)
Urea 7.1 mmol/L (2.0 - 7.0)
Creatinine 200 µmol/L (55 - 120)

His records show his creatinine was 119 µmol/L. The general practitioner refers the patient to the emergency department for further investigation.

Out of the options listed, which is the correct classification?

Answer 74

Acute Kidney Injury stage 1
KDIGO AKI stage 1
↑ creatinine 1.5-1.9 times, or
↓ urine output <0.5 mL/kg/hr for ≥ 6 hours

This patient has a reduced urine output and a rise in his serum creatinine by ~1.7x which are in keeping with a classification of AKI Stage 1. He has risk factors of age, diabetes mellitus diagnosis, and his use of NSAIDs for his back pain. It is important to note that an AKI is a classification, not a diagnosis.

The subsequent levels of AKI (stages 2 and 3) are outlined below and are progressively worsening renal function. They can be caused by similar risk factors (as outlined above in the vignette).

Stage 2 AKI is an increase in serum creatinine to 2-2.9 from baseline or reduction in urine output for 12 hours or more (< 0.5 ml/kg/hr). This vignette shows a renal function that is less dramatic than this, and as such, this is incorrect.

Stage 3 AKI is an increase in serum creatinine to 3x or higher from baseline or reduction in urine output for 24 hours or more (< 0.3 ml/kg/hr). As aforementioned, the vignette shows a renal function that is less affected than this, and as such, this is incorrect.

There is no AKI stage 4 so this is an incorrect answer. If the patient had a ‘Chronic Kidney Disease’ stage 4, he would have an eGFR of 15-29 ml/min/1.73m².

There is no AKI stage 5 so this is an incorrect answer. If the patient had a ‘Chronic Kidney Disease’ stage 5, he would have end-stage renal disease and an eGFR <15 ml/min/1.73m² (or be receiving renal replacement therapy).

While there are only 3 stages of AKI, chronic kidney disease is classified from stages 1-5.

Question 75

Michaela is a 54-year-old Greek woman who has recently had an NHS health check and has called her GP for the results. As part of this health check, she has had a blood pressure check, routine blood test and a urine dip. Her blood pressure is 125/78 mmHg and her urine dip is negative. Her blood test showed the following:

Hb 124 g/L Male: (135-180)
Female: (115 - 160)
Platelets 300 * 109/L (150 - 400)
WBC 4.5 * 109/L (4.0 - 11.0)
Na+ 138 mmol/L (135 - 145)
K+ 5.0 mmol/L (3.5 - 5.0)
Urea 4.2 mmol/L (2.0 - 7.0)
Creatinine 82 µmol/L (55 - 120)
eGFR 63 mL/min/1.73 m²

Which one of the following options describes the correct stage of Chronic Kidney Disease (CKD) in this patient?

Answer 75

No CKD
CKD: only diagnose stages 1 & 2 if supporting evidence to accompany eGFR
because although this patients eGFR is reduced her eGFR is above 60 and hence there needs to be evidence of kidney damage present for a diagnosis of CKD stage 2 to be made in this patient.

Question 76

CKD stage 1

Answer 76

can only be diagnosed if there is an eGFR >90 AND markers of kidney damage such as proteinuria or electrolyte disturbances.

Question 77

CKD stage 2

Answer 77

only be diagnosed if there is an eGFR 60-90 AND markers of kidney damage such as proteinuria or electrolyte disturbances. Remember CKD stage 1 and 2 requires markers of kidney damage for a diagnosis.

Question 78

CKD stage 3a

Answer 78

can only be diagnosed if there is an eGFR of 45-59 with or without markers of kidney damage.

Question 79

CKD stage 3b

Answer 79

an only be diagnosed if there is an eGFR of 30-44 with or without markers of kidney damage.

Question 80

A 65-year-old diabetic woman has noticed her urine has become frothy and presents to her GP. He performed a urinalysis and finds protein in the urine. As part of the workup of a suspected diabetic nephropathy, she is sent for an ultrasound. Which of the following would you expect to see in the ultrasound report?

Answer 80

Bilaterally enlarged kidneys

Chronic diabetic nephropathy will have large/normal sized kidneys on ultrasound whereas most patients with chronic kidney disease have bilateral small kidneys

In diabetic nephropathy, the kidneys can either be bilaterally enlarged (in early disease) or normal size (in later disease).

Question 81

Features of renal cell carcinoma:

Answer 81

classical triad: haematuria, loin pain, abdominal mass

pyrexia of unknown origin

left varicocele (due to occlusion of left testicular vein)

endocrine effects: may secrete erythropoietin (polycythaemia), parathyroid hormone (hypercalcaemia), renin, ACTH

25% have metastases at presentation

Question 82

Creatine kinase 14,550 I/U

Answer 82

Rhabdomyolysis
Being immobilised on the floor after a fall for many hours such as in this case is likely to cause rhabdomyolysis. Myoglobin released from muscle tissue is toxic to the kidneys, and will, therefore, produce acute kidney injury. The raised creatinine kinase, and to some degree, the raised potassium levels are typical features of rhabdomyolysis.

Question 83

A 42-year-old man with polyuria undergoes investigation. His results are as follows:

Urine Osmolality before tests 285 mOsm/kg * 109/l
After water deprivation test 283 mOsm/kg * 109/l
After exogenous anti-diuretic hormone (ADH) 290 mOsm/kg * 109/l

Which of the following medications may cause this picture?

Answer 83

Lithium is a recognised cause of nephrogenic diabetes insipidus

The lack of response to exogenous ADH suggests that this is nephrogenic diabetes insipidus (DI) as opposed to central (cranial) DI. Here, the kidneys are not sensitive to ADH. Lithium and demeclocycline are recognised causes.

Question 83

eGFR variables. When assessing his estimated glomerular filtration rate (eGFR)

Answer 83

CAGE - Creatinine, Age, Gender, Ethnicity
The correct answer is serum urea. The Modification of Diet in Renal Disease (MDRD) equation is a widely used formula to estimate the glomerular filtration rate (eGFR) in patients with chronic kidney disease. It requires four variables: age, serum creatinine, ethnicity, and gender. Serum urea is not included in the MDRD equation.

Age is an essential variable in the MDRD equation because the eGFR declines naturally with age. Therefore, it’s crucial to adjust for age when calculating eGFR to avoid overestimating kidney function in older individuals.

Serum creatinine is a key component of the MDRD equation since it’s a marker of kidney function. Creatinine is a waste product generated by muscle metabolism and excreted by the kidneys. When kidney function declines, serum creatinine levels rise, indicating reduced eGFR.

Ethnicity also plays a role in the MDRD equation as certain ethnic groups, particularly those of African descent, have been found to have higher average muscle mass and consequently higher baseline serum creatinine levels. Therefore, incorporating ethnicity into the equation helps ensure accurate estimation of eGFR across different populations.

Gender is another important variable in the MDRD equation since men typically have more muscle mass than women and thus produce more creatinine. Including gender allows for more accurate estimation of eGFR by accounting for these differences between males and females.

Question 83

Which of the following would indicate that the cause of this man’s presentation was chronic and not acute kidney disease?

Answer 83

Hypocalcaemia is an indication that kidney disease is chronic and not acute

This is because renal failure can result in reduced levels of metabolised vitamin D/1,25(OH)2D. This results in reduced calcium reabsorption in the kidneys.

Question 84

man has a work-up for hypertension. He has found to have blood + on a urine dipstick of a freshly voided sample. Which one of the following may account for this finding?

Answer 84

Exercise.

Haematuria, or the presence of blood in urine, can be caused by a range of factors. Strenuous exercise may cause haematuria due to trauma to the bladder, dehydration or the breakdown of red blood cells that happens with sustained aerobic exercise. This is known as ‘march hemoglobinuria,’ and it’s commonly seen in long-distance runners.

Question 85

screened for adult polycystic kidney disease?

Answer 85

Ultrasound is the screening test for adult polycystic kidney disease

Genetic testing is still not routinely recommended for screening family members

Question 86

A 45-year-old woman with type 1 diabetes mellitus is reviewed in the diabetes clinic. Three months ago her blood tests were as followed:

K+ 4.5 mmol/l
Creatinine 116 µmol/l
eGFR 47 ml/min

At the time she was started on lisinopril to treat both the hypertension and act as a renoprotective agent. Lisinopril had been titrated up to treatment dose. Her current bloods are as follows:

K+ 4.9 mmol/l
Creatinine 123 µmol/l
eGFR 44 ml/min

Of the following options, what is the most appropriate course of action?

Answer 86

No action

The small change in both the creatinine and eGFR are acceptable and below the threshold where ACE inhibitors should be stopped

Question 87

A 21-year-old woman who has been brought into the emergency department following a collapse. There is no further information about her available, however, an arterial blood gas has already been taken on room air and shows the following:

paO2 13 kPa (11 - 13)
paCO2 3.5 kPa (4.7 - 6)
pH 7.31 (7.35 - 7.45)
Na+ 143 mmol/L (135 - 145)
K+ 5 mmol/L (3.5 - 5.0)
Bicarbonate 17 mEql/L (22 - 29)
Chloride 100 mmol/L (98 - 106)

What diagnosis could explain the blood gas findings?

Answer 87

Septic shock

An anion gap of > 14 mmol/L typically indicates a raised anion gap metabolic acidosis, rather than a normal anion gap

Whilst in practice an arterial blood gas (ABG) would be used to aid diagnosis and management in the context of the patient’s history, examination and other investigation findings, in this case where we have no other information about the patient, the ABG alone can give us a clue towards the diagnosis. First, we can tell that the patient has a normal paO2, making a respiratory cause of her symptoms less likely. Her pH is, however, under 7.35, indicating an acidosis. Her bicarbonate is low, suggesting metabolic acidosis. Her low paCO2 shows some efforts to compensate. This is a partially compensated metabolic acidosis. To determine the cause of metabolic acidosis, the anion gap can be calculated. The anion gap is calculated by calculating the difference between positively charged ions (sodium and potassium) and negatively charged ions (bicarbonate and chloride). In this case (143 + 5) - (17 + 100) gives an anion gap of 31 mmol/L. A normal anion gap is 8-14 mmol/L. This patient, therefore, has metabolic acidosis with a raised anion gap. Raised anion gap shows there is excess acid in the blood. The only listed cause of raised anion gap metabolic acidosis is septic shock, which results in acidosis due to the production of lactic acid due to inadequate tissue perfusion.