Clinical cases for self-analysis and concept building

1. Clinical Case discussions- set-1
Professor (Dr.)Namrata Chhabra
Ph.D. Medical Biochemistry (Scholar),
MPhil Health Professions Education,
CMCL FAIMER Fellow- Regional Institution,
MD(Biochemistry), M.B.B.S.
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2. Spot-1
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3. Write the normal reference range
A 56-year-old diabetic, reported to the physician’s office for a
routine visit to monitor his treatment.
His physician drew blood for an HbA1C determination. The
laboratory reported a value of 8.5%.
• What is the normal reference range of HbA1c and
• What is the significance of its measurement?
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4. Answer
• Normal level of HbA1c- 4.0–6.0%
• Significance-HbA1c is an important indicator of long-term glycemic
control with the ability to reflect the overall glycemic history of the
preceding three-four months (120 days).
• HbA1c not only provides a reliable measure of chronic hyperglycemia
but also correlates well with the risk of long-term diabetes
complications.
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5. Spot-2
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6. Case study
• A 28-year-old man was admitted to the hospital with a week-long
history of severe vomiting.
• He confessed to self medication for his chronic heart burns and
indigestion.
• He was clinically severely dehydrated and had shallow respiration.
• Initial biochemical results were:
• pCO2- 44 mmHg, Serum Bicarbonate- 41 mEq/L, pH-7.5.
• Comment on the acid- base status
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7. Answer
• High pH, high serum bicarbonate and near normal pCO2.
• This is a case of compensated metabolic alkalosis.
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8. Spot-3
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9. Urine analysis report
A. Physical Examination
• Color: Straw colored
• Appearance: Clear
• Odor: Aromatic
• pH: 6.0
• Specific Gravity: 1.030
• Volume: 150 ml
B. Chemical Examination
•Sugar: ++++
• Proteins: nil
• Bilirubin: nil
• Bile Salts: nil
• Ketone bodies: nil
What might be the most probable diagnosis ?
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10. Answer
• High specific gravity, and
• Glucose in urine, indicate that,
• It is a case of glycosuria (precisely glucosuria).
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11. Spot-4
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12. Mechanism of action of the displayed drug
• An unskilled worker in a water garden was sent to
sweep up a spill of a white powder in the storage shed.
• Later he was found with labored breathing and
convulsions.
• On further examination, the white powder was
identified as rotenone.
• Respiratory distress was induced on rotenone
exposure.
• What is the mechanism of action of Rotenone?
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13. Answer
• Rotenone is an inhibitor of electron transport chain.
• It blocks electron transfer in NADH-Q oxidoreductase (complex I) and
thereby prevents the utilization of NADH as a substrate in the
electron transport chain.
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14. Spot-5
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15. Enzyme Inhibition
• Name an anticancer drug
that works by the
mechanism shown in the
picture.
• What might be the effect of
that drug on the affinity of
the enzyme for its true
substrate?
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16. Answer
• The graph shows the mechanism of action of a competitive enzyme
inhibitor. Vmax is constant; however, Km is increased.
• Km denotes the affinity of an enzyme for its substrate. Km is reversely
associated with enzyme’s affinity for its substrate; higher the Km
value lesser the affinity of the enzyme for its substrate and vice versa
• Therefore, in the presence of a competitive enzyme inhibitor, the
affinity of the enzyme for its substrate is decreased.
• Methotrexate is an example of an anticancer drug that works by
competitively inhibiting Dihydrofolate reductase enzyme.
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17. Spot-6
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18. Clinical diagnosis
• A 21-year-old young woman, who recently began taking birth control
pills, presents to the emergency room with cramping abdominal pain,
anxiety, paranoia, and hallucinations.
• A surgical evaluation, including ultrasound and computed
tomography (CT) scan, fails to demonstrate an acute abdominal
process.
• A urine analysis reveals an increase in urine porphyrins.
• Which enzyme defect might be responsible for clinical
manifestations in this disease?
• What is the most probable diagnosis ?
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19. Answer
• The patient is suffering from Acute intermittent porphyria.
• The typical combination of abdominal pain, psychiatric symptoms and
increased amounts of urinary porphyrins & their precursors are
indicative of Acute intermittent porphyria.
• Enzyme defect- Deficiency of Porphobilinogen deaminase.
• Symptoms are triggered by oral contraceptive pills.
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20. Spot-7
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21. Defective TCA cycle enzyme
• A post-operative patient on intravenous fluids develops lesions in the
mouth (angular stomatitis).
• Urinalysis indicates an excretion of 15 μg riboflavin/mg creatinine,
which is abnormally low.
• Which of the following TCA cycle enzymes is most likely to be
affected?
A. Citrate synthase
B. Isocitrate dehydrogenase
C. Fumarase
D. Malate dehydrogenase
E. Succinate dehydrogenase
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22. Answer
• It is clearly a case of Riboflavin deficiency.
• Out of all, Succinate dehydrogenase is the only TCA cycle enzyme that
is FAD dependent.
• Therefore, the activity of Succinate dehydrogenase will be most
affected in Riboflavin deficiency.
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23. Spot-8
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24. Interpret from the findings
• An 18-year-old girl
child has been
brought to Pediatric
O.P.D in a semi-
conscious state. The
blood and urinary
findings have been
displayed. Write the
most probable
diagnosis and the
reason for your
conclusion.
A B
Results of GOD-POD
method
B S T
Urinalysis
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25. Answer
• The color intensity of test sample (T) is higher than that of
Standard(S).
• Given the concentration of standard as 100 mg%, the test sample has
glucose concentration higher than of standard (hyperglycemia).
• Urine also shows the presence of glucose (glucosuria), and ketone
bodies (ketonuria), as evident from positive Benedict’s and Rothera’s
test respectively.
• Therefore, it is clearly a case of Diabetic ketoacidosis, biochemically as
well as clinically.
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26. Spot-9
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27. Interpret from the findings
• Calculate the creatinine clearance
of a patient with following
findings:
• Serum creatinine-3 mg/dL,
• Urinary volume -1500 ml/ day
• Urinary creatinine -0.75 G/L.
• Urinary protein ++++
• State the diagnosis.
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B s T

28. Answer
• Creatinine clearance(C)= UV/P
• Where U= Urinary creatinine (mg/dl)
• V= Volume of urine excreted (ml/day)
• P= Serum Creatinine (mg/dl)
• Thus, applying the values-
• V= 1500 ml/day, convert to ml/ minutes
• i.e., = 1500/24x60= 1.1 ml/minute (Approximately)
• U= 0.75 G/L, Convert it to mg/dl
• i.e. 75 mg/dl
• Creatinine clearance (C) = 75x1.1/3 = 27.5 ml/minute
• It is much below the physiological range;
• Proteinuria is also there, hence it might be a case of renal failure (impaired renal functions)
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29. Spot-10
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30. Identify and state the significance of each of the
techniques A and B
A B
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31. Answer
• Technique A- Paper electrophoresis, frequently used for isolating
proteins, amino acids and oligopeptides
• Technique B- Thin layer chromatography frequently used to separate
mixtures.
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32. Spot-11
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33. State the diagnosis
• A 64-year-old man presented to the emergency department with a 3-
day history of chest pain and shortness of breath.
• He complained that his face and extremities had a blue color.
• History revealed that he was a known patient of chronic unstable
angina for which he was taking nitroglycerine and Isosorbide
dinitrate.
• Blood obtained for analysis was chocolate –colored.
• What is the most likely diagnosis?
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34. Answer
• The symptoms are suggestive of Methemoglobinemia.
• Isosorbide dinitrate (ISDN) has been used in the treatment of
Ischaemic cardiovascular diseases for many years.
• ISDN is the most popular nitric oxide donor and causes
methemoglobinemia as an important side-effect.
• Symptoms are suggestive of Methemoglobinemia caused by ISDN.
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35. Spot-12
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36. What is the most probable diagnosis ?
• The main symptom is bleeding (hemorrhage)—into the skin (causing
bruises), from the nose, from a wound, in the stomach, or in the
intestine.
• Blood may be seen in the urine or stool.
• In newborns, life-threatening bleeding within or around the brain may
occur.
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37. Answer
• This is a case of vitamin K deficiency
• A deficiency of vitamin K can lead to extreme bleeding, which can
begin as a gum, nose discharge, bruising, bleeding in the cavities or
internal hemorrhages.
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38. Spot-13
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39. Spot question
• “Babies undergoing
phototherapy for
physiological jaundice are
prone to develop
riboflavin deficiency”
• What might be the
reason ?
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40. Answer
• Riboflavin is extremely light sensitive; therefore, upon exposure to
blue light during phototherapy, it undergoes degradation.
• Milk should be stored in containers that protect against
photodegradation.
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41. Spot-14
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42. Spot diagnosis
• A teenage girl presents with moderate to severe
epigastric pain.
• Physical examination reveals extensive eruptive
xanthomas and hepatosplenomegaly.
• A blood sample reveals milky plasma.
• What might be the possible diagnosis ?
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43. Answer
• The clinical picture is suggestive of Familial lipoprotein lipase
deficiency(hyperchylomicronemia).
• A variant of this diseases can be produced by deficiency of apo CII.
• It is present in early childhood, and is manifested by eruptive
xanthomas, recurrent abdominal pain with no premature
cardiovascular disease.
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44. Spot-15
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45. Make a diagnosis from the displayed clinical and laboratory
findings. What is the underlying defect ?
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46. Answer
• This is clearly a case of congenital erythropoietic porphyria that
occurs due to the deficiency of uroporphyrinogen III synthase
enzyme.
• Severe cutaneous hypersensitivity, Erythtrodontia (teeth are reddish-
brown and fluoresce on exposure to long-wave ultraviolet light) and
purple colored urine are suggestive of congenital erythropoietic
porphyria .
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47. Spot-16
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48. State the diagnosis and mention the underlying
defect
S-4-

49. Answer
• The picture is indicative of xerophthalmia that occurs due to vitamin A
deficiency.
• Xerophthalmia results from keratinization of the conjunctiva.
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50. Thank you
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