1. CASE STUDIES, QUESTIONS, QUIZ (acid base, renal failure, HTNBy
Dr Waqar
MBBS, MRCP
Assistant Professor
Maarefa Medical College

2. CASE STUDIES IN
Case 1
A 24 year old female with broken ankle was brought to the E.R. with severe pain.
ABG showed the following :
* pH: 7.55/ pCO2: 27/ pO2; 105/ HCO3: 20
What is the acid base disturbance?

3. ANSWER 1
* pH is 7.55 ( high), so alkalosis. * HCO3 is 20 (not high), so not metabolic process. * pCO2 is 27(low, because patient has tachypnea due to pain excess CO2 is passed out) So, alkalosis is due to respiratory problem RESPIRATORY ALKALOSIS

4. CASE 2
A 45 yr. old female , suffering from asthma, was brought to the E.R. due to severe asthma attack. Very few rhonchi on chest auscultation. She looked exhausted. ABGs showed : * pH: 7.25 * pCO2: 50mmHg * pO2: 55mmHg * HCO3: 30meq What is the acid-base abnormality?

5. ANSWER 2
* pH is 7.25(low) : acidosis * HCO3 is 30(high), so can not be metabolic acidosis. * pCO2 is 50 (high), so acidosis is due to respiratory problem: RESPIRATORY ACIDOSIS * HCO3 is high due to compensation

6. CASE 3
A 25 yr old male was brought to E.R. due to palpitations. He looked very anxious and was breathing heavily. Systemic exam was normal. ABGs showed : * pH: 7.53/ pCO2: 23mmHg/ HCO3: 20 What is the abnormality?

7. ANSWER 3
* pH is 7.53(high) , so alkalosis * HCO3 is 20(not high), so cannot be metabolic alkalosis * pCO2 is 23(low), so alkalosis is due to resp. problem : RESPIRATORY ALKALOSIS

8. CASE 4
A 60 yr old man was brought to the E.R. He looked lethargic and very dehydrated. ABGs showed: * pH: 7.10/ pCO2: 13.8/ HCO3: 14 *Na: 131, * K: 4.2 * Cl : 85 * Lactic acid: 23( ) What is the acid base abnormality & what is the cause of this abnormality?

9. ANSWER 4
* pH is 7.10 (low), so acidosis. * pCO2 is 13.8(low), so cannot be respiratory cause. * HCO3 is 14( low), so metabolic problem: METABOLIC ACIDOSIS Next, calculate the A.G. to find out the type of metabolic acidosis

10. ANSWER 4 contd.
A.G = (Na + K) - ( Cl + HCO3)- remember = ( ) – (85+14) = 36 Normal A.G. is 8 to 16, so this is high anion gap metabolic acidosis. *Remember MUDPILES? ( methanol, uremia, DKA, paraldehyde, infection lactic acidosis, ethanol, salicylate) So the cause of metabolic acidosis in this case is “ lactic acidosis”( due to dehydration)

11. CASE 5
A 60 yr old heavy smoker is a known case of COPD. He now c/o cough with purulent sputum and fever since 2 days.You suspect COPD exacerbation. He was drowsy & cyanosed. ABGs showed: * pH: 7.2/ pCO2: 80/ pO2 :50/HCO3: 30 What is the likely acid base abnormality?

12. ANSWER 5
* pH is 7.2( low), so acidosis * pCO2 is 70 (high), so problem is resp. * HCO3 is not low , so cannot be metabolic acidosis * So: RESP. ACIDOSIS ( Due to COPD exacerbation & CO2 retention) Why is HCO3 little slightly? ( due to compensation)

13. CASE 6
A 40 yr old man has HTN. He is taking thiazide diuretic. On routine analysis, his ABGs show: * pH:7.49/ pCO2: 48/ HCO3:34 What is the metabolic abnormality & what is the cause?

14. ANSWER 6
* pH is 7.49(high), so alkalosis. * pCo2 is 48 ( slight high), so cannot be resp. alkalosis * HCO3 is 32 (high), so problem is metabolic So, METABOLIC ALKALOSIS Cause: all Diuretics- except acetazolamide (pCO2 is slightly high due to compensation)

15. CASE 7
A 5 yr old boy c/o polyphagia & polyuria since 1 month. Blood sugar, serum ketones and urine ketones were high. Pt. was dehydrated. ABGs : * pH: 7.20/ pCO2: 21/ HCO3: 15 * Na: 140 *K: 3.6 *Cl:100 What is the acid base abnormality & what is the cause?

16. ANSWER 7
* pH is 7.20 (low), so it is acidosis * pCO2 is 21(low), so cannot be resp. acidosis * HCO3 is 15( low), so it is metabolic problem METABOLIC ACIDOSIS * Anion gap : 28.6 ( very high) * Serum sugar& ketones are high So : Diabetic Ketoacidosis

17. QUICKIES
1) pH: ) pH: 6.1 3) pH: ) pH: ) pH; 7.30, pCO2: 50, HCO3: 30 6) pH: 7.48, pCO2: 25, HCO3: 19 7) pH: 7.21, pCO2: 30, HCO3: 18 8) pH: 7.52, pCO2: 48, HCO3: 34

18. ANSWERS OF QUICKIES Acidosis Alkalosis Normal Acidosis, respiratory
Alkalosis, resp.
Acidosis, metabolic
Alkalosis, metabolic

19. Case 8
A young man got in a car accident. He had too much blood loss. On admission to hospital, his BP is 90/60 & pulse is 120. His blood tests show: * Creatinine : 5 mg% * Urine output very low Q1)What is the cause of renal failure in this patient? (renal, pre-renal or post renal) Q2) What will be the osmolality of urine, high or low?

20. Answer case 8
1) Pre renal( blood not coming to kidney ) 2) Urine osmolality will be high ( kidneys absorbing water, so urine is concentrated)

21. Case 9
A patient was started on chemotherapy for his lymphoma. After 1 day, he developed high creatinine & renal failure. Q 1) What substance is causing this problem? Q2) What type of renal failure is this? (pre-renal, renal or post renal) Q3) How can you prevent this problem?

22. Answer Case 9
Uric acid is causing the problem (chemotherapy causes destruction of the cancer cells, so excess uric acid is released from the cells and it causes uric acid nephropathy)
Renal type of renal failure
3) Can be prevented by giving i.v. fluids( good hydration) before starting chemo. & the drug Allopurinol ( for gout also) which prevents uric acid formation

23. Case 10
A 70 year old man c/o pain and heaviness in the flanks since a few weeks. On exam, you find enlarged kidneys (palpable).The urinary bladder is also palpable. He has very little urine output. Investigations show high creatinine. Q1) What type of renal failure is this? ( pre-renal, renal or post renal) Q2) What is the likely cause? Q3) What step will you take immediately to help this patient?

24. Case 10 answer
1) Post renal type of renal failure 2) BPH 3) Immediately put a Foley’s catheter to drain the urine

25. Some quickies
1) What is the aim of BP in most patients? 2) What should be the BP in diabetic patients? 3) Name some causes of secondary HTN? 4) Name 3 side effects of ACE inhibitors? 5) Name any 2 conditions where you should not give ACEi? 6) If a person is taking an ACEi , which 2 blood tests should you do regularly? 7) Name any 2 conditions where you should avoid beta blockers?

26. Answers of Quickies Less than 140/90 In DM, should be less than 130/80
Sec. HTN: Chronic kidney diseases, Renal artery stenosis, Cushing’s, pheochromocytoma.
S/E of ACEi: cough, hyperkalemia, high creatinine,angioedema, rash
Don’t give ACE in : pregnancy, creatinine rising continuously, severe hyperkalemia
Regularly check serum K & creatinine
Avoid beta blockers in : asthma, bradycardia, Peripheral vascular disease, acute CHF

27. Which type of casts?
1) Glomerular damage casts? 2) Tubule damage casts? 3) Interstitial nephritis casts?

28. Answers for casts
1) RBC casts 2) granular casts ( tubule damage) 3) WBC casts ( interstitium)

29. Q1) What are the stages of CRF
Q1) What are the stages of CRF? Q2) Name 2 causes of anemia in CRF patients? Q3) Name any 2 complications of CRF? Q4) What is the treatment of acidosis in CRF patients? Q5) What are the 2 most common causes of CRF worldwide? Q6) If neurologic complications happen in a patient with CRF, what is the treatment? Q7) Which 2 vaccines should be given to CRF patients and also in other chronic diseases?

30. CRF stages 1 to 5
Erythropoeitin deficiency & also Fe(iron) def.
CRF complications: Bone disease, HTN, neuro complications(coma, siezures, neuropathy), anemia, acidosis, pericarditis, High K & P
Na bicarbonate tabs. May need dialysis
DM, HTN
Dialysis is done to treat neuro S/S & pericarditis
Pneumovac, Flu vaccine

31. Question
My uncle came to me yesterday and c/o headache. I checked his BP and it was 160/95. No past history of HTN. I told him that you have HTN, and I started him on Capoten ( ACEi). Did I do right or wrong?

32. Answer
I did wrong. Don’t diagnose HTN based on 1 reading. Always check twice on 2 different days. In this case I can give him simple panadol for the headache and then check BP again after a few days. ( If BP is very high like in hypertensive crisis, then we can start treatment at that time)

33. Case 11
A patient came to me for headache. His BP was as follows: day 1: 150/98 After few days: 160/96 After trying low salt diet & exercise for 2 months, BP is still not normal so I start an ACEi & call him after 4-5 days. After 4-5 days, his BP is still high, 150/94, so I increase the dose of ACEi. Did I do right or wrong? Why?

34. Answer case 11
I did wrong. Don’t change the dose of the medicine so soon. Give at least 2-3 weeks for the medicine to have maximum effect.