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The following acid/ base values were obtained: pH = 7.45, [HCO3-] = 12mmoles/l, PCO2 = 2.7kPa (20mmHg)
The subject is clearly very unwell The subject is likely to have spent a long time at altitude The subject needs bicarbonate The subject is unlikely to be hypoxic This is typical of a metabolic alkalosi
The subject is likely to have spent a long time at altitude
Alkalosis, cause: reduced Pco2 ,bicarbonate reduced accordingly, pH protected
Therefore correct answer is b
stay at high altitude causes hyperventilation and reduced Pco2, significantly reduced bicarbonate indicates reduction of renal glutaminase activity to reduce bicarbonate reabsportion
A patient with lung cancer develops the syndrome of inappropriate ADH secretion. Which of the following values for Na+ concentration might be expected to be seen?
140mmol/L 145mmol/L 150mmol/L 138mmol/L 155mmol/L
138mmol/L
Some small cell lung cancer either produce ADH themselves or might indirectly trigger an increased ADH release from the pituitary.
As a results more water is reabsorbed at the CD and osmolarity decreases.
So we are looking for Na+ concentrations that are lower than normal.
The following values were made for an elderly female diabetic patient’s creatinine clearance: 24hr urine volume 1.44l, serum creatinine concentration 100 micromol/L, urine creatinine concentration 6.6mmoles/L.
Clinical features of renal impairment would be expected
Serum creatinine alone indicates impaired renal function
Serum potassium should be measured urgently
The data suggest there may be renal impairment
There is reason to suspect an incomplete renal collection
The data suggest there may be renal impairment
First we need to convert the Urine volume into a urine flow rate:
1.44l/24h = 0.06l/h=0.001l/min
Now using the clearance formula: (UCr x V) / PCr = (6.6 mmol/l x 0.001l/min)/ (0.1mmol/l) = (0.0066 mmol/min) / (0.1 mmol/l) = 0.066l/min
= 66ml/min Creatinine clearance
Compared to a normal GFR of 125ml/min we can assume a renal impairment.
The following acid/base values were obtained: pH = 7.25, [HCO3-] = 12mmoles/l, PCO2 = 3.3kPa (25mmHg)
They are indicative of a respiratory acidosis
The reduction in PCO2 is a result of under-breathing
The subject has probably been taking bicarbonate of soda
It could be related to impaired renal function
The subject may have been vomiting very badly
It could be related to impaired renal function
Acidosis, this can either be caused by Pco2 or [HCO3-]
We can clearly see that [HCO3-] is reduced. This fact can be explained by d. A failing kidney is not able to reabsorb all bicarbonate causing metabolic acidosis.
Pco2 is to low for a respiratory acidosis, under-breathing increases Pco2, taking bicarbonate will increase [HCO3-] and vomiting causes loss of H+ and alkalosis.
The commonest urological malignancy in patients with painless frank haematuria is:
Kidney cancer Testicular cancer Bladder cancer Penile cancer Prostate cancer
Bladder cancer
Percentage of Na and water absorption in the Collecting Duct of the nephron is
5-20%
with
*5-20% of Na+ and water reabsorption in the kidney may occur in the Collecting Duct.
- 15-20% of Na+ and water reabsorption in the kidney occurs in the Loop of Henle.
- 65-75% of Na+ and water reabsorption by secondary active transport in the kidney occurs in the PCT.
What is the commonest type of renal tract stones in adults?
Calcium phosphate Calcium oxalate Cystine Magnesium ammonium phosphate Uric acid
Calcium oxalate
A 60 year old man has stage 5 CKD with a serum creatinine of 500 micromol/l, (normal 88-116). Which of the following is likely to be present?
High serum calcium Low serum phosphate High serum phosphate Normal serum calcium Normal serum phosphate
High serum phosphate
*In kidney failure you get high serum phosphate and low serum calcium
Kidney failure affects Vitamin D causing hypocalcaemia
Low eGFR causes serum phosphate to increase because the kidney cant excrete it any longer.
PTH will be highly activated in this case taking calcium from the bones and causing renal bone disease i.e. due to secondary hyperparathyroidism
A 17-year-old boy presents to the emergency department at 1 am with a 3 hour history of pain in his right testicle. He denies any trauma but does a lot of long distance running. Examination is difficult due to pain; however the right testicle does appear to be swollen, slightly red and extremely tender. Which of the following do you do next?
Admit for urgent ultrasound scan the next morning
Contact the urologist on call and organise urgent ultrasound scan
Contact the urologist on call and prepare for theatre
Obtain a urine sample and prescribe antibiotics
Prescribe strong analgesia and advise to stop running till symptom resolve
Contact the urologist on call and prepare for theatre
*This patient has presented with an acutely painful testicle and torsion of the testis must be confirmed or excluded by exploration. A Doppler ultrasound can confirm the diagnosis but will delay definitive treatment and therefore, in any potential case of torsion, time must not be wasted in trying to obtain a scan. The testis will remain viable if explored and fixed within 6 hours but, if delayed to 12 hours, the viability rate is around one in five.
Testicular torsion is a urological emergency with an incidence of 1/4000 in males under the age of 25, and a peak incidence between the ages of 12 and 18 years. Other causes of an acutely painful scrotum include torsion of the testicular appendage acute epididymitis and strangulated inguinal hernias
The following acid/base values were obtained: pH = 7.28, [HCO3-] = 36mmoles/l, PCO2 = 8kPa (60mmHg)
This is typical of an acute respiratory acidosis.
The subject will be excreting large amounts of bicarbonate ions
The subject will be excreting large amount of ammonium ions
The plasma potassium level is likely to be decreased
He has a metabolic alkalosis because of the raised bicarbonate
The subject will be excreting large amount of ammonium ions
Acidosis, ↑ Pco2 and ↑ [HCO3-]. ↑ Pco2 is the cause (probably chronic bronchitis or similar), ↑ [HCO3-] for compensating pH.
This can only be achieved by massive increase in formation of new bicarbonate which requires the excretion of ammonium ions. Therefore the correct answer is c.
In this context it is clear why a,b and e are not correct but how about d?
Protons are often buffered intracellularly in exchange for potassium.
Therefore in this case an increase in potassium is more likely than a decrease.
GFR would increase if:
There is afferent arteriole constriction
There is efferent arteriole constriction
There is an increase in tissue pressure in Bowman’s capsule
There is an increased release of renin from the JG cells
There is an obstruction of the ureters
There is efferent arteriole constriction
GFR increases when filtration pressure increases, which, in this case, can only be achieved by increasing the resistance in the efferent arteriols by increasing constriction.
All other actions would rather decrease GFR
The following acid/base values were obtained: pH = 7.50, [HCO3-] = 45mmoles/l, PCO2 = 8kPa (60mmHg)
This may be the result of bad diarrhoea
The subject will be excreting bicarbonate ions
The subject will be excreting ammonium ions
The plasma potassium level is likely to be increased
The subject has a respiratory acidosis because of the raised PCO2
The subject will be excreting bicarbonate ions
Alkalosis, ↑ Pco2 and ↑ [HCO3-]. According to the table before the cause can only be an increase in bicarbonate (various possible causes), the elevated PCO2 is only the compensation to protect the pH.
To solve the problem [HCO3-] need to be excreted so answer b is correct.
Again, note answers d, ↑ [K+] might be seen as a result of an acidosis, so in an alkalosis it is more likely to see a reduced plasma [K+].
How would drinking a large amount of water affect osmolarity and volume of the ECF?
Decreased osmolarity and increased volume
Both would increase
No change in osmolarity and increased volume
No change in either
Greater increase in ECF volume than ICF volume
Decreased osmolarity and increased volume
Adding volume to the existing fluid volume
Since the solute content in plain water can be neglected the solutes present in the body will now be diluted in a larger volume hence the osmolarity goes down.
The following antibiotics are generally suitable for empirical treatment of complicated urinary traction infections except:
Vancomycin Ciprofloxacin Ceftriaxone Gentamicin Co-amoxiclav
Vancomycin
Percentage of Na and water absorption in the Loop of Henle of the nephron is
15-20%
