16- A 75 year old man presents with a long history of shortness of breath and ankle oedema. His serum biochemistry shows sodium 122 mmols/l and potassium of 2.9 mmols/l. He now complains of weakness.Which of the following is likely to explain the above biochemical picture?
1) Addison's Disease
2) Nephrotic syndrome
3) Primary hyperaldosteronism
4) SIADH
5) Diuretic therapy
Answers-5
The long history of his symptoms and serum biochemistry suggests that his condition is due to treatment with frusemide for CCF.
17- A 15-year-old girl was seen by her family physician because of increasing lethargy. She had a recent history of the "flu". Biochemistry tests show that she has renal impairement.
serum sodium 140 mmol/L (137 - 144) serum potassium 4.2 mmol/L (3.5 - 4.9) serum urea 28 mol/L (2.5 - 7.5) serum creatinine 280 µmol/L (60 - 110) Her condition does not improve after several weeks on corticosteroid therapy, so a renal biopsy is performed. The biopsy demonstrates the presence of segmental sclerosis of 3 of 10 glomeruli identified in the biopsy specimen. Immunofluorescence studies and electron microscopy do not reveal evidence for immune deposits. What is the most appropriate advice to give regarding her condition?
1) She has an underlying malignancy
2) She may require a renal transplant in 10 years
3) She will improve if she loses weight
4) She will likely develop a restrictive lung disease
5) She will probably improve with additional corticosteroid therapy
Answers-2
The findings point to focal segmental glomerulosclerosis (FSGS), which leads to chronic renal failure in half of cases. The lack of resolution with corticosteroid
therapy and the progression to chronic renal failure is what sets FSGS apart from minimal change disease.
18- Which of the following concerning the pH of urine is correct?
1) is a useful indicator of the acid/base balance of the blood
2) rises on a vegetarian diet
3) is determined by the concentration of ammonium
4) is lower than 5.5 in renal tubular acidosis
5) would be above 7.0 after prolonged and severe vomiting
Answers-2
c - excretion of ammonium occurs when an acid urine is produced but the pH of urine is of course determined by the concentration of H+ ions d-unable to lower
the pH to less than 5.5 in RTA e- This would be expected in an attempt to compensate for the loss of acid however when there is extracellular fluid depletion
the retention of sodium takes priority. Instead of bicarbonate being excreted it is reabsorbed in the proximal and distal nephron and this perpetuates the metabolic
alkalosis until the fluid balance is restored with IV fluids.
19- A young child presents with respiratory distress, worsening over 2 days. Blood gases show a pH of 7.25, a PCO2 of 7.5kPa, a PO2 of 8.5kPa, and a base excess of -4. Which of the following interpretations is correct?
1) Results are consistent with bronchopulmonary dysplasia.
2) Blood gases suggest type 1 respiratory failure.
3) Immediate intubation is required.
4) Results are consistent with late severe asthma.
5) Bicarbonate may be necessary to correct the acidosis.
Answers-4
In interpreting blood gas results, the following sequence may be useful:
Inspect the pH: Is it low, normal or high?
Inspect the CO2: Is it low, normal or high?
Inspect the PO2: Is it low, normal or high?
If the pH is low then an acidosis is present, and inspecting the CO2 will enable you to determine whether this is due to respiratory or metabolic causes. Inspecting the PO2 will tell you whether the child is hypoxic or not. In this case, the pH is reduced, and the CO2 is high, with a base deficit of only -4, insufficient to explain the acidosis from metabolic causes. This is, therefore, a respiratory acidosis, and the PO2 is also a little low suggesting type 2 respiratory failure. Possible causes would include pneumonia, early hyaline membrane disease, ARDS. In asthma, the initial stages show a low CO2, with this climbing only as a pre-terminal event. The results would therefore be consistent with late severe asthma. In bronchopulmonary dysplasia, there is usually long-term CO2 retention with
compensatory increase in bicarbonate leading to a positive base excess and normal pH. Bicarbonate is usually only considered if the base deficit exceeds about
-8 or 00.
20 -A 45-year-old solicitor had an onset of severe, crushing, substernal chest pain while attending a football match. He collapsed on his way to the car. Bystander Cardiorespiratory Resuscitation was begun immediately and continued until arrival in Casualty where an endotracheal tube was inserted and ventilation was maintained on
100% oxygen. Investigations revealed: pH 7.13 PaO2 560 mmHg PaCO2 18 mmHg Bicarbonate 5.8 SaO2 98% Based on these laboratory values, which of the following statements best describes his current pathophysiology?
1) He is demonstrating a primary respiratory alkalosis
2) He probably developed a large right to left intracardiac shunt
3) His anion gap is probably normal
4) His oxyhemoglobin curve is shifted to the left
5) His pulmonary artery pressure is probably elevated
Answers-5
This young patient with severe central chest pain has probably arrested due to myocardial infarction and arrhythmia. His gases reveal high PO2 following 100%
O2 but severe acidosis due to the arrest and lactic acidosis thus anion gap would be high. He does not have a primary ventilatory failure as his PO2 is high. There is
no left to right shunting and high pulmonary pressures would be expected after this arrest scenario.
1) Addison's Disease
2) Nephrotic syndrome
3) Primary hyperaldosteronism
4) SIADH
5) Diuretic therapy
Answers-5
The long history of his symptoms and serum biochemistry suggests that his condition is due to treatment with frusemide for CCF.
17- A 15-year-old girl was seen by her family physician because of increasing lethargy. She had a recent history of the "flu". Biochemistry tests show that she has renal impairement.
serum sodium 140 mmol/L (137 - 144) serum potassium 4.2 mmol/L (3.5 - 4.9) serum urea 28 mol/L (2.5 - 7.5) serum creatinine 280 µmol/L (60 - 110) Her condition does not improve after several weeks on corticosteroid therapy, so a renal biopsy is performed. The biopsy demonstrates the presence of segmental sclerosis of 3 of 10 glomeruli identified in the biopsy specimen. Immunofluorescence studies and electron microscopy do not reveal evidence for immune deposits. What is the most appropriate advice to give regarding her condition?
1) She has an underlying malignancy
2) She may require a renal transplant in 10 years
3) She will improve if she loses weight
4) She will likely develop a restrictive lung disease
5) She will probably improve with additional corticosteroid therapy
Answers-2
The findings point to focal segmental glomerulosclerosis (FSGS), which leads to chronic renal failure in half of cases. The lack of resolution with corticosteroid
therapy and the progression to chronic renal failure is what sets FSGS apart from minimal change disease.
18- Which of the following concerning the pH of urine is correct?
1) is a useful indicator of the acid/base balance of the blood
2) rises on a vegetarian diet
3) is determined by the concentration of ammonium
4) is lower than 5.5 in renal tubular acidosis
5) would be above 7.0 after prolonged and severe vomiting
Answers-2
c - excretion of ammonium occurs when an acid urine is produced but the pH of urine is of course determined by the concentration of H+ ions d-unable to lower
the pH to less than 5.5 in RTA e- This would be expected in an attempt to compensate for the loss of acid however when there is extracellular fluid depletion
the retention of sodium takes priority. Instead of bicarbonate being excreted it is reabsorbed in the proximal and distal nephron and this perpetuates the metabolic
alkalosis until the fluid balance is restored with IV fluids.
19- A young child presents with respiratory distress, worsening over 2 days. Blood gases show a pH of 7.25, a PCO2 of 7.5kPa, a PO2 of 8.5kPa, and a base excess of -4. Which of the following interpretations is correct?
1) Results are consistent with bronchopulmonary dysplasia.
2) Blood gases suggest type 1 respiratory failure.
3) Immediate intubation is required.
4) Results are consistent with late severe asthma.
5) Bicarbonate may be necessary to correct the acidosis.
Answers-4
In interpreting blood gas results, the following sequence may be useful:
Inspect the pH: Is it low, normal or high?
Inspect the CO2: Is it low, normal or high?
Inspect the PO2: Is it low, normal or high?
If the pH is low then an acidosis is present, and inspecting the CO2 will enable you to determine whether this is due to respiratory or metabolic causes. Inspecting the PO2 will tell you whether the child is hypoxic or not. In this case, the pH is reduced, and the CO2 is high, with a base deficit of only -4, insufficient to explain the acidosis from metabolic causes. This is, therefore, a respiratory acidosis, and the PO2 is also a little low suggesting type 2 respiratory failure. Possible causes would include pneumonia, early hyaline membrane disease, ARDS. In asthma, the initial stages show a low CO2, with this climbing only as a pre-terminal event. The results would therefore be consistent with late severe asthma. In bronchopulmonary dysplasia, there is usually long-term CO2 retention with
compensatory increase in bicarbonate leading to a positive base excess and normal pH. Bicarbonate is usually only considered if the base deficit exceeds about
-8 or 00.
20 -A 45-year-old solicitor had an onset of severe, crushing, substernal chest pain while attending a football match. He collapsed on his way to the car. Bystander Cardiorespiratory Resuscitation was begun immediately and continued until arrival in Casualty where an endotracheal tube was inserted and ventilation was maintained on
100% oxygen. Investigations revealed: pH 7.13 PaO2 560 mmHg PaCO2 18 mmHg Bicarbonate 5.8 SaO2 98% Based on these laboratory values, which of the following statements best describes his current pathophysiology?
1) He is demonstrating a primary respiratory alkalosis
2) He probably developed a large right to left intracardiac shunt
3) His anion gap is probably normal
4) His oxyhemoglobin curve is shifted to the left
5) His pulmonary artery pressure is probably elevated
Answers-5
This young patient with severe central chest pain has probably arrested due to myocardial infarction and arrhythmia. His gases reveal high PO2 following 100%
O2 but severe acidosis due to the arrest and lactic acidosis thus anion gap would be high. He does not have a primary ventilatory failure as his PO2 is high. There is
no left to right shunting and high pulmonary pressures would be expected after this arrest scenario.
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