Copy of Nephrology Module 2

A patient in the Emergency Department has the laboratory results shown below:

Serum Sodium 130 mmol/L [136 – 146 mmol/L]

Serum Potassium 6.5 mmol/L [3.5 – 5.0 mmol/L]

Serum HCO3 14 mmol/L [22 – 28 mmol/L]

Serum Chloride 115 mmol/L [95 – 107 mmol/L]

Venous pH 7.19 [7.34 – 7.44]

PCO2 42 mmHg [35 – 45 mmHg]

Base excess 10 mmol/L [-3- + 3 mmol/L]

Which of the following is the most likely cause of the acidosis?

A four-year-old boy presents with facial oedema and dark urine two weeks after a bout of tonsillitis. He has been anuric for 18 hours. Initial investigations confirm acute renal failure with markedly elevated serum urea and creatinine. His serum potassium is elevated at 6.8 mmol/L.

Which of the following reduces total body potassium?

As glomerular filtration rate (GFR) declines, urinary creatinine clearance overestimates GFR because creatinine is:

Which one of the following drugs may be cleared by hemodialysis?

A 50-year-old man presenting for an insurance medical examination is found to be hypertensive with a resting blood pressure of 170/110 mmHg. He takes no medication.

The following laboratory investigations were obtained while on a normal diet:

serum potassium 2.8 mmol/L [3.5-5.0]

serum sodium 145 mmol/L [135-145]

serum creatinine 0.095 mmol/L [0.080-0.120]

urinary potassium 65 mmol/L

urinary sodium 80 mmol/L

plasma renin 100 mU/L [8-70]

plasma aldosterone 800 pmol/L [ambulant 350-700]

Which one of the following diagnoses best fits the clinical picture?

A 35-year-old man is found to be hypertensive with a blood pressure of 180/110 mmHg. At presentation, on no treatment, the following results are obtained:

serum potassium 3.3 mmol/L [3.5-5.0]

urinary potassium 40 mmol/24 h [<30]

plasma aldosterone 620 pmol/L [supine 50-450]

plasma renin 4 mU/L [ambulatory 5-75]

The most appropriate next investigation is measurement of:

A 43-year-old woman presents with a six month history of hypertension which has been difficult to control. She is now taking three agents for her blood pressure control. She has a serum potassium of 2.7 mmol/L [3.6 – 5.2 mmol/L] and you are concerned about primary hyperaldosteronism(Conn’s syndrome).

Which of the following medications is most likely to interfere with the interpretation of an aldosterone:renin ratio result?

A patient with primary aldosteronism secondary to a unilateral adrenal hyperplasia undergoes an adrenalectomy.

Which of the following is most likely to improve post surgery?

Which of the following is the main site of sodium reabsorption in the nephron?

Which of the following is the site of action for acetazolamide?

The concomitant use of which medication will increase the risk of lithium toxicity in the blood?

Frusemide blocks which of the following co-transporter?

Which of the following is the correct order of events in the reninangiotensin system in response to low blood pressure?

A) Kidneys reabsorb sodium and water uptake is increased

B) The kidneys sense low blood pressure.

C) Renin is released into the blood and produces Angiotensin I.

D) Release of Aldosterone, ADH, and thirst stimulation.

E) Angiotensin Converting Enzyme (ACE) converts Angiotensin I to Angiotensin II.

A 19 year old girl presents with weakness.She is on no medications and has 4 siblings.One sister has had low potassium levels.Physical exam and BP are normal.

Investigations:

Sodium 141
Potassium 2.4
Cl 98
Bicarbonate 32
Calcium 2.3
Mg 0.35
Urine:
Na 60
K 50
Cl 100
Prostaglandin E normal

What is the most likely diagnosis?

A 56 year old woman is on hemodialysis for end stage renal failure due to diabetes.

Investigation reveals:

Hb of 90g/L

Ferritin of 80(15-180 g/L)

Transferrin saturation 20%(15-46%)

What is the most appropriate treatment?

Erythropoietin is predominantly made from which type of cell in the kidney?

A 65-year-old woman, established on haemodialysis for nine months, is maintained on erythropoietin 4,000 units twice a week intravenously. Previously her haemoglobin (Hb) had remained steady in the range of 105 – 115 gm/L. She now presents with a Hb of 89 gm/L on routine testing. There have have been no changes to her erythropoietin dose or other medications. Her mean corpuscular volume(MCV) is 84 fL [78- 98], her serum iron is 13 micromol/l [13-35], iron saturation is 18% [15- 46], serum ferritin is 630 microg/l [20-300] and her reticulocyte count is 30 x 109/L [12-100].

Which of the following is the most likely cause for her erythropoietin resistance?

A 16-year-old post pubertal boy has chronic renal failure with a serum creatinine of 300 micromol/L due to glomerulonephritis. Two years ago his creatinine was 100 micromol/L and one year ago it was 200 micromol/L. He wants to complete his schooling in two years time before undergoing pre-emptive living related transplantation. He is growing on the 25th percentile for height and the 10th for weight (having gained height but not weight in the last year). His blood pressure is 140/105 mmHg and he has 2.0 g per day of proteinuria. His dietary protein content is 2 g/kg/day.

His serum chemistry is:

sodium 140 mmol/L [135-150]

potassium 4.0 mmol/L [3.5-5.0]

chloride 105 mmol/L [90-110]

urea 45 mmol/L [<6]

creatinine 0.3 mmol/L [0.05-0.12]

haemoglobin 90 g/L [120-150]

calcium 2.4 mmol/L [2.26-2.56]

phosphate 2.6 mmol/L [0.94-1.37]

parathyroid hormone 70 pg/ml [2-7]

Which one of the following will have no effect on the progression to end-stage renal failure?

The predominant cause of anaemia in chronic renal failure is:

A 45-year-old woman presents with a three-year history of recurrent rash, characterised as palpable purpura over both legs. Some of these lesions have ulcerated.

Laboratory results include:

• Serum creatinine 0.10 mmol/L [0.06-0.11]
• alanine transaminase (ALT) 51 U/L [15-50]
• aspartate transaminase (AST) 64 U/L [15-45]
• hepatitis C antibody positive
• cryoglobulins positive with 8% cryoprecipitate
• Urinalysis is normal.

Which of the following is the most appropriate management?

A 40-year-old man was found to have elevated liver enzymes and positive hepatitis C serology since 2000. Liver biopsy showed chronic active hepatitis consistent with hepatitis C.

He now presents with purpuric rash on his knee,joint pains and Raynauds phenomenon.

Which one of the following is the most appropriate next investigation?

A 23-year-old woman presents with generalised swelling. Over the last three days she has felt tired, has experienced bilateral loin pain and has noticed darkening of her urine. She has had a skin infection on her knee which has been slow to resolve.

On examination, she has mild generalised oedema, a blood pressure of 170/115 mmHg and tenderness in the loins. The skin lesion is still encrusted and erythematous. Urinalysis shows ++proteinuria and ++blood. Other examination is unremarkable.

Investigations show:
Full blood count normal
Serum biochemistry:
sodium 135 mmol/L [137-146]
potassium 5.1 mmol/L [3.5-5.0]
chloride 102 mmol/L [98-108]
bicarbonate 21 mmol/L [26-30]
urea 44.0 mmol/L [3.5-8.5]
creatinine 0.72 mmol/L [0.06-0.12]
albumin 35 g/L [35-45]
total protein 60 g/L [55-90]
Microurine shows:
red blood cells >100 per high power field [0-1]
white blood cells 10-50 per high power field [0-1]
red cell casts present [0]
Serological investigations show:
antinuclear antibody (ANA)
antineutrophil cytoplasmic antibody (ANCA) negative
antistreptolysin-O titre (ASOT) not elevated
antiDNAse-B titre 200 U [<30]
cryoglobulins positive
complement component 3 (C3) 0.30 g/L [0.55-1.20]
complement component 4 (C4) 0.18 g/L [0.20-0.50]
throat culture negative
Apart from control of blood pressure, fluid and electrolyte management and acute dialysis if indicated, the most appropriate therapy for this renal disease is:

A 15-year-old teenager is admitted to hospital because he has been lethargic for the past three to four weeks. He appears to be thirsty all the time with recent weight loss. He has been getting up to pass urine three times each night for the past two weeks. There is no history of drug ingestion or infection. There is no past history of note. Clinical examination is unremarkable.

His initial investigations show the following:
serum:
sodium 135 mmol/L [135-146]
potassium 3.0 mmol/L [3.5-5.0]
urea 16.0 mmol/L [3.2-7.7]
creatinine 0.29 mmol/L [0.04-0.08]
glucose 3.5 mmol/L [2.5-7.0]
urinalysis 1+ protein, no blood, moderate glucose
urine microscopy 40 white cells,

The most likely diagnosis in this patient is:

A young woman presents with thirst and polyuria. Following overnight water deprivation, which one of the following is the best indicator that she has partial (and central) diabetes insipidus rather than psychogenic polydipsia?

A young man is identified as having haematuria (>50,000 red blood cells/mL). This is associated with a trace of protein on urine dipstick testing on several occasions. His blood pressure is 110/70 mmHg and no abnormalities are detected on physical examination.

His serum biochemistry results are:
creatinine 0.08 mmol/L [0.08-0.12]
urea 4.5 mmol/L [4.0-8.0]
sodium 135 mmol/L [135-145]
potassium 3.5 mmol/L [3.5-5.0]
chloride 95 mmol/L [93-105]
glucose 3.5 mmol/L [3.5-7.0]

The most likely diagnosis is:

Persistent reduction of serum complement component 3 (C3) is most strongly associated with which one of the following forms of glomerulonephritis?

A 56-year-old woman presents with generalised swelling including legs, hands and face and no other relevant history. She has had a normal examination two years prior. Apart from oedema, the only abnormality on current examination is a blood pressure of 170/105 mmHg. Urinalysis shows protein ++++, blood ++, dysmorphic red cells, red cell casts and granular casts.

Abnormal blood tests are:
urea 18 mmol/L [3.0-8.5]
creatinine 0.205 mmol/L [0.040-0.100]
total protein 55 g/L [63-80]
albumin 25 g/L [35-45]
cholesterol 7.5 [<5.5]
triglycerides 2.5 [0.10-2.10]
ANA, ANCA (anti-neutrophil cytoplasmic antibody) and anti glomerular basement membrane assays are all negative.

The most likely renal pathology is:

A 12-year-old girl presents to the emergency department with swollen eyes and ankles for one week. She has been lethargic and complained of back and right flank pain for approximately 10 days. Examination reveals a well grown adolescent with blood pressure 120/84 mmHg. She has pitting oedema up to her thighs and her liver is palpable 2 cm below the right costal margin and is tender. Urine microscopy shows 400 red cells, red and white cell casts and 4+ protein.

Blood tests show:
haemoglobin 85 g/L [115-150]
white cell count 4.62 x 109/L [4.40-12.50]
segmented neutrophils 3.33 x 109/L [1.50-7.40]
lymphocytes 1.02 x 109/L [1.50-4.70]
platelet count 110 x 109/L [150-400]
plasma creatinine 0.10 mmol/L [0.04-0.08]

Which one of the following is the most likely diagnosis?

A 45-year-old woman has had six episodes of nephrotic syndrome over the last five years. The initial episodes responded promptly and completely to oral prednis(ol)one, but recent episodes have responded more slowly. At the completion of her last course of prednis(ol)one two weeks ago, urine protein was 500 mg/day

Which one of the following is the most likely diagnosis?

The trichrome-stained renal biopsy is shown below.

A 25-year-old man has recurrent haematuria. He had microscopic haematuria noted during an admission with pneumonia six months earlier. Follow up urine microscopy was normal a month later. He has developed macroscopic haematuria following a recent throat infection which lasted six days. Examination is unremarkable.

Investigations show a normal full blood count, creatinine, electrolytes, calcium, liver function, clotting screen and chest radiograph. A midstream specimen of urine shows 90 red blood cells per high powered field but no casts or protein. Urine culture is sterile.

The most likely diagnosis is: