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Case Charts VMMC-1 - Full Content Summary

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Glucose Metabolism / Diabetes (Slides 2-6, 12)

Slide 2 - Normal OGTT

• Task: Study the given GTT curve and comment.
• Findings: Fasting BG 75 mg/dl, Peak 135 mg/dl @ 1 hr, returns to 70 mg/dl @ 2.5 hr. No urine sugar or ketones.
• Diagnosis: Normal OGTT curve.

Slide 3 - Diabetes Mellitus (OGTT)

• Task: Interpret the OGTT graph.
• Findings: Fasting BG 180 mg/dl, Peak 300 mg/dl, returns to 170 mg/dl. Urine sugar ++ to +++, no ketones.
• Diagnosis: Diabetes Mellitus (WHO criteria: fasting >126 mg/dl, 2hr >200 mg/dl).

Slide 4 - Renal Glycosuria

• Scenario: 45-yr-old man, fasting BG 80 mg/dl (normal), but urine sugar positive (+) after heavy breakfast at 150 mg/dl.
• Findings: BG peak 150 mg/dl, returns to 105 mg/dl. Glycosuria despite normal blood glucose.
• Diagnosis: Lowered renal threshold - Renal Glycosuria.

Slide 5 - DM without Complications

• Scenario: 40-yr-old male, increased appetite, calf pain x 3 months.
• Findings: Fasting BG 145 mg/dl, 2hr PP 210 mg/dl, urine sugar 2+, no albumin, no ketones.
• Diagnosis: Diabetes Mellitus without complications.

Slide 6 - Diabetic Ketoacidosis (DKA)

• Scenario: 25-yr-old Type I DM, unconscious, rapid and deep (Kussmaul) breathing.
• Findings: pH 7.2 (acidosis), HCO3 10 mEq/L (low), BG 450 mg%, urine sugar +++, urine ketones +++.
• Diagnosis: Diabetic Ketoacidosis (DKA).
• Mechanism: Organic acids (acetoacetic acid, beta-hydroxybutyric acid) elevated; bicarbonate buffer consumed, pH falls.
• Ketone bodies named: Acetone, Acetoacetic acid, Beta-hydroxybutyric acid.

Slide 12 - Starvation Ketoacidosis

• Scenario: Patient with altered sensorium.
• Findings: BG 55 mg/dl (hypoglycemia), pH 7.27, urine Benedict's negative, Rothera's test positive (ketonuria).
• Diagnosis: Starvation Ketoacidosis.

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Acid-Base Disorders (Slides 7-11)

Slide 7 - Respiratory Acidosis

• Scenario: 70-yr-old male, unconscious after crush in crowd.
• Findings: pH 7.2, HCO3 28 mEq/L (normal/compensated), pCO2 70 mmHg (elevated).
• Diagnosis: Respiratory Acidosis.

Slide 8 - Metabolic Acidosis (Diarrhea)

• Scenario: Patient with weakness, vomiting, diarrhea ~15x/day, low BP, feeble pulse.
• Findings: pH 7.23, HCO3 14 mEq/L (low), pCO2 38 mmHg (normal).
• Diagnosis: Metabolic Acidosis due to diarrhea.

Slide 9 - Metabolic Alkalosis

• Scenario: 62-yr-old male with excess vomiting and excessive antacid use.
• Findings: pH 7.52, HCO3 36 mEq/L (elevated), pCO2 38 mmHg (normal), serum Cl 86 mEq/L (low - hypochloremia).
• Diagnosis: Metabolic Alkalosis.

Slide 10 - Respiratory Acidosis (COPD)

• Scenario: 60-yr-old with chronic cough, severe dyspnea.
• Findings: pH 7.12, pCO2 80 mmHg (elevated), HCO3 26 mEq/L (normal).
• Diagnosis: Respiratory Acidosis.

Slide 11 - Respiratory Alkalosis

• Scenario: Hysterical patient with hyperventilation.
• Findings: pH 7.6, pCO2 21 mmHg (low), HCO3 28 mEq/L.
• Diagnosis: Respiratory Alkalosis.

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Liver Function Tests / Jaundice (Slides 13-16)

Slide 13 - Normal LFT

• Findings: All values within normal limits (bilirubin, AST, ALT, ALP, proteins, albumin).
• Interpretation: Normal LFT report.

Slide 14 - Hemolytic (Pre-hepatic) Jaundice

• Scenario: 2-day-old baby with jaundice (yellow skin/sclera), refusing feeds, vomiting.
• Findings: Total bilirubin 25 mg% (very high), direct 0.7 (indirect ~24.3 mg/dl), AST 60, ALT 73. Urine: urobilinogen +++, bile salts negative, bile pigments negative.
• Diagnosis: Neonatal Physiological Jaundice / Hemolytic (pre-hepatic) jaundice.
• Notes: Test for indirect bilirubin = van den Bergh test. Kernicterus = unconjugated bilirubin crosses BBB, deposits in brain.

Slide 15 - Hepatic (Hepatocellular) Jaundice

• Scenario: Female office worker, loss of appetite, vomiting, fatigue, right hypochondrium pain, enlarged tender liver.
• Findings: Total bilirubin 12 mg/dl, direct 7.6, indirect 4.4. AST 140, ALT 380, ALP 110. Urine: bile salts +, bile pigments +, urobilinogen +.
• Diagnosis: Hepatic (Hepatocellular) Jaundice.
• Why elevated AST/ALT: Liver parenchymal cell damage causes enzyme leakage into blood.

Slide 16 - Obstructive (Post-hepatic) Jaundice

• Scenario: 55-yr-old male, yellow urine, itching, colicky abdominal pain, yellow sclera.
• Findings: Total bilirubin 22.6, direct 18.3 (predominantly conjugated), SGOT 62, SGPT 121, ALP 310 (markedly elevated), serum protein 4.8 (low), albumin 1.6 (low), prothrombin time prolonged. Urine: urobilinogen absent (bile flow obstructed).
• Diagnosis: Obstructive (Post-hepatic/Cholestatic) Jaundice.

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Cardiac Enzymes / MI (Slides 17, 31, 32)

Slide 17 - Acute MI - Enzyme Profile

• Scenario: 50-yr-old male, severe chest pain, ECG: acute ischemic changes.
• Biochemical parameters: Troponin I, Troponin T, CK-MB.
• First enzyme to rise: Creatine Phosphokinase (CPK/CK).
• Most specific isoenzyme: CK-MB (CK-2).
• Enzyme persisting after initial attack: LDH.

Slide 31 (labeled 17A) - Early MI Enzymes

• Scenario: 50-yr-old, chest pain radiating to left shoulder/arm, within few hours of onset.
• Answers: CK rises first; Normal CK: 15-100 IU/L (male), 10-80 IU/L (female); Elevated isoenzyme: CK-2 (CK-MB).

Slide 32 (labeled 17B) - MI Interpretation

• Scenario: Obese middle-aged person, dizziness, shortness of breath, chest pain. Elevated CK, LDH, AST. Normal LFTs.
• Diagnosis: Myocardial Infarction.

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Pancreatic / GI (Slides 18, 28, 30)

Slide 18 - Acute Pancreatitis

• Scenario: Acute abdominal pain, elevated serum amylase.
• Diagnosis: Acute Pancreatitis.
• Normal serum amylase: 50-120 U/L.
• Amylase action: Cleaves alpha-1,4 glycosidic bonds of starch to produce maltose.

Slide 28 (labeled 31A) - Acute Pancreatitis

• Scenario: Acute abdominal pain. Elevated serum amylase, serum lipase, and urine amylase (diastase).
• Diagnosis: Acute Pancreatitis.
• Normal serum amylase: 50-120 IU/L; serum lipase: 50-175 IU/L; urinary amylase (diastase): 0-375 IU/L.

Slide 30 (labeled 31B) - Chronic Pancreatitis

• Scenario: 40-yr-old occasional alcoholic, severe abdominal pain after large meal/alcohol, nausea, vomiting.
• Findings: Serum amylase 280 IU/L (elevated), urinary amylase 520 IU/L (elevated).
• Diagnosis: Chronic Pancreatitis.

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Renal / Protein Disorders (Slide 19)

Slide 19 - Nephrotic Syndrome

• Scenario: 10-yr-old girl, generalized body swelling, facial puffiness, fatigue, loss of appetite.
• Findings: 24hr urine protein 4.8 g/day (massive proteinuria), serum total protein 4.2 g/dl (low), serum albumin 1.6 g/dl (low), A/G ratio 0.6:1 (reversed), cholesterol 350 mg/dl (high).
• Diagnosis: Nephrotic Syndrome.

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Vitamins / Deficiencies (Slides 20, 21)

Slide 20 - Night Blindness

• Scenario: School boy with progressive diminished vision in evenings/nights for 1 month.
• Diagnosis: Night Blindness (Nyctalopia).
• Deficiency: Vitamin A (beta-carotene).
• Sources: Mango, carrots, papaya.

Slide 21 - Rickets

• Scenario: 5-yr-old male child, pigeon chest, bowed legs, short stature.
• Findings: Serum Ca 6.7 mg/dl (low), serum phosphorus 2.2 mg/dl (low), ALP 575 U/L (markedly elevated).
• Diagnosis: Rickets.

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Endocrine (Slide 22)

Slide 22 - Hypothyroidism

• Scenario: 50-yr-old female teacher, hoarseness of voice, tiredness x 6 months, weight gain, prefers warm weather.
• Diagnosis: Hypothyroidism.
• Investigations and normal ranges:
  • TSH: 0.5-5 mIU/L
  • Total T3: 120-190 ng/dl
  • Total T4: 5-12 mcg/dl

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Inborn Errors of Metabolism (Slides 23, 24, 25, 26, 29)

Slide 23 - Alkaptonuria

• Scenario: Child's urine turns black on exposure to sunlight x 2 hours; Benedict's test positive.
• Diagnosis: Alkaptonuria.
• Deficient enzyme: Homogentisate Oxidase.

Slide 24 - Wilson's Disease

• Scenario: 32-yr-old male painter, vision problems, Kayser-Fleischer rings in both eyes.
• Findings: Serum ceruloplasmin 14 mg/dl (low, normal 25-50), plasma copper 60 µg/dl (low, normal 70-150).
• Diagnosis: Wilson's Hepatolenticular Degeneration.
• Mechanism: Defective gene for copper-binding ATPase; copper accumulates in liver and brain.

Slide 25 - Tetany

• Scenario: Male with muscle cramps, numbness, painful spasm of hands and feet.
• Findings: Serum Ca 6.5 mg/dl (low), phosphate 5.5 mg/dl (slightly elevated), albumin normal (4.0), ALP normal (120).
• Diagnosis: Tetany (hypocalcemia; not due to albumin decrease).

Slide 26 - Wilson's Disease (Pediatric)

• Scenario: 10-yr-old boy, abdominal pain, behavior disturbances, enlarged liver, Kayser-Fleischer rings.
• Findings: Serum copper 40 µg/dl (low), ceruloplasmin 5 mg/dl (very low), urine copper 200 µg/dl (elevated, normal <25).
• Diagnosis: Wilson's Hepatolenticular Degeneration.
• Treatment: Penicillamine (copper chelation); Zinc (reduces copper absorption).

Slide 29 - Lesch-Nyhan Syndrome

• Scenario: 4-yr-old boy, learning disability, aggressive behavior, joint pain, self-mutilation (biting fingers/lips).
• Findings: Uric acid 11 mg/dl (high, normal 3.5-7).
• Diagnosis: Lesch-Nyhan Syndrome.
• Deficient enzyme: HGPRTase (Hypoxanthine-Guanine Phosphoribosyl Transferase).

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Purine Metabolism (Slide 27)

Slide 27 - Gout

• Scenario: 50-yr-old non-vegetarian male, severe joint pain.
• Findings: Serum uric acid 12 mg/dl (elevated, normal 3.5-7), urinary uric acid 2.5 mg/dl (low).
• Diagnosis: Gout (hyperuricemia with decreased urinary excretion of uric acid).

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Topics Covered - Quick Reference

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VMMC-1 Case Charts - Full Answers with Explanations

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SLIDES 2 & 3 - OGTT (Oral Glucose Tolerance Test)

What is the OGTT?

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Slide 2 - Normal OGTT Curve

• Fasting glucose is between 70-100 mg/dl - normal.
• After glucose load, blood sugar rises (due to glucose absorption from gut).
• Peak is 135 mg/dl - stays below 140 mg/dl, so no diabetic threshold crossed.
• Returns to near-fasting by 2.5 hr - insulin is working efficiently, cells are taking up glucose.
• Renal threshold for glucose is ~180 mg/dl. Since peak never reaches 180, no glucose spills into urine. Urine sugar is nil - as expected.
• Conclusion: Normal beta-cell function and normal insulin sensitivity.

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Slide 3 - Diabetic OGTT Curve

• Fasting glucose 180 mg/dl is already well above the diagnostic threshold of 126 mg/dl.
• Peak of 300 mg/dl is massively elevated - insulin secretion is deficient or cells are resistant.
• The curve never comes back to normal even at 2.5 hr - impaired glucose disposal.
• WHO criteria for DM: Fasting plasma glucose >126 mg/dl AND/OR 2-hr value >200 mg/dl on OGTT.
• Glucose exceeds renal threshold (180 mg/dl), so glucose spills into urine - glycosuria present.
• No ketones: This is likely Type 2 DM (some residual insulin to suppress lipolysis) or early Type 2.

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Slide 4 - Renal Glycosuria

• Normal renal threshold for glucose: ~180 mg/dl. Below this, kidneys reabsorb ALL filtered glucose; none appears in urine.
• Here, urine sugar appears at 150 mg/dl - the threshold is abnormally LOW (lowered renal threshold).
• This is NOT diabetes: fasting glucose is completely normal (80 mg/dl), OGTT curve is within normal limits.
• The defect is in the kidney (reduced SGLT-2 reabsorption capacity in proximal tubule), NOT in glucose metabolism.
• Key distinction from DM: In DM, glycosuria occurs because blood glucose is high (above normal threshold). In renal glycosuria, blood glucose is normal but kidney is "leaky."
• This is a benign condition requiring no treatment, but must be distinguished from diabetes.

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Slide 5 - Diabetes Mellitus without Complications

• Both diagnostic criteria are met: Fasting >126 AND 2hr PP >200 mg/dl.
• Polyphagia (increased appetite) is a classic DM symptom: despite high blood glucose, glucose cannot enter cells without insulin, so cells are "starving," driving hunger signals.
• Calf muscle pain: early peripheral neuropathy or peripheral vascular disease due to hyperglycemia.
• No albumin in urine: nephropathy not yet developed (no diabetic nephropathy).
• No ketones: still producing enough insulin to suppress fat breakdown (Type 2 pattern).
• Complications absent = no nephropathy, no ketonemia.

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Slide 6 - Diabetic Ketoacidosis (DKA)

• In severe insulin deficiency (Type I DM), cells cannot use glucose.
• The body breaks down fat (lipolysis) as an alternative energy source.
• Excess Acetyl-CoA from fat oxidation enters ketogenesis pathway in the liver.
• This produces ketone bodies: Acetone, Acetoacetic acid, Beta-hydroxybutyric acid.
• Acetoacetic acid and beta-hydroxybutyric acid are organic acids - they donate H+ ions, lowering blood pH.
• The bicarbonate buffer system tries to neutralize: HCO3- + H+ → H2CO3 → H2O + CO2.
• This depletes bicarbonate (HCO3 drops to 10 mEq/L), causing a fall in pH to 7.2.

• The respiratory center detects low pH.
• The body compensates by hyperventilating (rapid, deep breathing) to blow off CO2, which raises pH partially.
• This is respiratory compensation for metabolic acidosis.

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Slide 7 - Respiratory Acidosis (Crush Injury)

• The primary abnormality is elevated pCO2 (70 mmHg). CO2 is the "respiratory acid."
• Crush injury likely compressed the chest wall or caused pain, preventing normal breathing. CO2 accumulates.
• CO2 + H2O → H2CO3 → H+ + HCO3-. Excess CO2 → excess H+ → pH falls.
• Rule: In respiratory acidosis - pH is low, pCO2 is high.
• HCO3 is slightly elevated (28) - the kidney is retaining bicarbonate to compensate (metabolic compensation), but it takes 2-3 days to be complete.
• Respiratory acidosis = hypoventilation. Any cause of poor ventilation: chest compression, COPD, sedation, neuromuscular disease.

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Slide 8 - Metabolic Acidosis (Diarrhea)

• The primary problem is low HCO3 (14 mEq/L) with normal pCO2.
• Diarrhea causes massive loss of bicarbonate-rich fluid from the intestine (the pancreatic and intestinal secretions are alkaline - rich in HCO3-).
• Loss of HCO3- = loss of base = metabolic acidosis.
• Rule: In metabolic acidosis - pH is low, HCO3 is low.
• Vomiting alone causes metabolic alkalosis (loss of HCl from stomach). But here diarrhea predominates, causing acidosis.
• Low BP + feeble pulse = hypovolemic shock from fluid loss.
• pCO2 is still normal/slightly low - respiratory compensation (hyperventilation to blow off CO2) is beginning.

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Slide 9 - Metabolic Alkalosis (Vomiting + Antacids)

• Primary problem = elevated HCO3 (36 mEq/L).
• Vomiting causes loss of HCl from the stomach. Loss of H+ ions = gain of base effect → alkalosis.
• Antacids (NaHCO3 or Mg/Al hydroxides) neutralize stomach acid AND when absorbed can raise serum HCO3.
• Hypochloremia: Loss of Cl- from vomiting. The kidney also tries to retain Cl- by exchanging it with HCO3- but this adds to alkalosis. Low Cl- perpetuates the alkalosis.
• pCO2 is normal here (no respiratory compensation yet), which is consistent with an acute metabolic alkalosis.

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Slide 10 - Respiratory Acidosis (COPD)

• Chronic cough + dyspnea = chronic obstructive lung disease (COPD or emphysema).
• Damaged alveoli cannot expel CO2 efficiently. CO2 accumulates → pCO2 rises to 80 mmHg.
• CO2 + H2O → H2CO3 → H+ + HCO3-. Excess H+ lowers pH to 7.12.
• HCO3 is still normal (26 mEq/L) - in a chronic setting you'd expect it to be elevated as renal compensation, but here it hasn't kicked in significantly or the acidosis is severe enough to override it.
• Severe respiratory acidosis - pH of 7.12 is life-threatening.

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Slide 11 - Respiratory Alkalosis (Hyperventilation)

• Hyperventilation = excessive breathing out of CO2.
• pCO2 falls to 21 mmHg (very low).
• Low CO2 → less H2CO3 → fewer H+ ions → pH rises to 7.6.
• Rule: Respiratory alkalosis = pH high, pCO2 low.
• Common causes: anxiety/hysteria, fever, salicylate poisoning, high altitude, mechanical overventilation.
• Patients often develop tingling in hands/feet and carpopedal spasm (hypocalcemic effect from alkalosis - more calcium binds to albumin, reducing free ionized calcium).
• Treatment: breathe into a paper bag to re-breathe CO2.

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Slide 12 - Starvation Ketoacidosis

• In prolonged starvation/fasting, glucose stores (glycogen) are depleted.
• The body turns to fat breakdown (lipolysis) for energy.
• Excess Acetyl-CoA from beta-oxidation of fatty acids is diverted to ketone body synthesis.
• Ketone bodies (acetoacetic acid, beta-hydroxybutyric acid) are acids - they lower pH → ketoacidosis.
• Blood glucose is LOW (55 mg/dl) because there is no dietary intake and glycogen stores are exhausted.
• Key difference from DKA: In DKA, blood glucose is HIGH (>300 mg/dl). In starvation ketoacidosis, blood glucose is LOW or normal. Both show positive Rothera's test (ketones).
• Rothera's test = detects ketone bodies (acetone + acetoacetic acid) in urine. Positive = mauve/purple ring.

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Slide 13 - Normal LFT

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Slide 14 - Pre-hepatic (Hemolytic) Jaundice - Neonatal

• In the newborn, fetal hemoglobin (HbF) is replaced by adult HbA. The excess breakdown of RBCs releases large amounts of heme.
• Heme → unconjugated (indirect) bilirubin. The neonatal liver is immature - it cannot conjugate bilirubin fast enough.
• Result: massive rise in unconjugated (indirect) bilirubin (24.3 mg/dl).
• Unconjugated bilirubin is NOT water-soluble, so it does NOT appear in urine (bile salts and pigments are negative).
• Some conjugated bilirubin does reach the gut → converted to urobilinogen → some reabsorbed and excreted in urine (urobilinogen +++).
• Bile salts and bile pigments negative in urine = no biliary obstruction.

• Unconjugated bilirubin is lipid-soluble. At very high levels, it crosses the blood-brain barrier (BBB) and deposits in the basal ganglia and brain stem.
• This causes brain damage (kerniterus) - leading to cerebral palsy, hearing loss, intellectual disability.
• This is why neonatal jaundice is treated urgently with phototherapy (converts unconjugated bilirubin to water-soluble isomers that can be excreted).

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Slide 15 - Hepatic (Hepatocellular) Jaundice

• Liver cell (hepatocyte) damage from virus or toxin causes BOTH types of bilirubin to rise (both direct and indirect elevated).
• Liver cells that are damaged leak their enzymes into blood - hence MASSIVE rise in ALT (380) and AST (140). ALT is more specific to liver. ALT:AST ratio >1 suggests hepatocellular damage.
• Damaged hepatocytes cannot properly conjugate OR excrete bilirubin - so both fractions rise.
• Some conjugated bilirubin regurgitates back into blood from damaged cells → appears in urine as bile pigments and bile salts.
• ALP is only mildly elevated (not obstructive pattern) - confirms hepatocellular rather than cholestatic.
• Urobilinogen is positive because some bile still enters the gut, is converted to urobilinogen, and is absorbed.

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Slide 16 - Obstructive (Post-hepatic) Jaundice

• Blockage of bile duct → bile cannot flow into intestine → conjugated (direct) bilirubin backs up into blood → predominantly direct hyperbilirubinemia.
• Conjugated bilirubin is water-soluble → spills into urine (dark/yellow urine, bile pigments + in urine).
• ALP markedly elevated (310) - ALP is produced by bile duct epithelium; it is the hallmark enzyme of obstructive jaundice. Obstruction causes ALP to be released and rise dramatically.
• Urobilinogen ABSENT - key diagnostic clue. Because no bile reaches the gut, no urobilinogen is formed. Its absence from urine and stool (pale/clay-colored stools) is pathognomonic of obstruction.
• Pruritus (itching): bile salts accumulate in the skin due to obstruction, causing intense itching.
• Low albumin + hypoproteinemia: long-standing obstruction impairs fat absorption → fat-soluble vitamins (A, D, E, K) are not absorbed.
• Prolonged prothrombin time: Vitamin K is a fat-soluble vitamin needed for clotting factors II, VII, IX, X. Without bile, Vitamin K cannot be absorbed → clotting factors deficient → PT prolonged → bleeding tendency.

Summary: Differentiating the Three Types of Jaundice

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Slides 17, 31, 32 - Myocardial Infarction (MI)

Cardiac Enzyme Timeline:

• When cardiac muscle cells die (infarction), they release their intracellular enzymes into blood.
• CK (Creatine Kinase) rises first - within 3-6 hours of MI onset. Used for early diagnosis.
• CK-MB (isoenzyme 2): CK has 3 isoenzymes: CK-MM (muscle), CK-BB (brain), CK-MB (heart). CK-MB is specific to cardiac muscle. Its rise confirms the heart is the source (not skeletal muscle injury).
• Troponin I and T: Most sensitive and specific cardiac markers. Even small infarcts elevate troponin. They stay elevated for up to 10 days, useful for diagnosing MI even if patient presents late.
• LDH: Rises late, peaks at 3-6 days. Useful when patient presents >48 hours after the event (when CK-MB has already normalized). LDH has 5 isoenzymes; LDH1 > LDH2 (flipped ratio) is specific to MI.
• In Slide 32: CK, LDH, and AST all elevated with normal LFT = MI, NOT liver disease. AST is found in both heart and liver; normal LFTs rule out liver cause.

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Slides 18, 28, 30 - Pancreatitis

Slide 18 & 28 - Acute Pancreatitis

• The pancreas produces digestive enzymes (amylase, lipase, trypsin, etc.) that are normally released into the duodenum.
• In pancreatitis, the acinar cells are inflamed/damaged → enzymes leak into blood.
• Serum amylase rises within 2-12 hours and returns to normal in 3-5 days (short window).
• Serum lipase rises slightly later but stays elevated longer (up to 14 days) - more specific to the pancreas than amylase (amylase also comes from salivary glands).
• Urinary amylase (diastase): Because amylase is small enough to be filtered by glomeruli, elevated blood amylase → elevated urinary amylase (diastase). Normal urinary amylase = 0-375 IU/L.
• What does amylase do? Cleaves alpha-1,4 glycosidic bonds in starch → produces maltose units (disaccharide). This is a digestive function.
• Common causes: gallstones, alcohol.

Slide 30 - Chronic Pancreatitis

• Chronic alcohol use causes repeated bouts of pancreatitis, progressive fibrosis of pancreatic tissue.
• Elevated amylase (but may be lower than acute pancreatitis in late chronic disease because acinar tissue is destroyed).
• The pain following large meals or alcohol is because these stimulate pancreatic secretion, which cannot pass through inflamed/fibrosed ducts → pressure builds → pain.
• Long-term: pancreatic exocrine insufficiency (malabsorption, steatorrhea) and endocrine insufficiency (diabetes).

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Slide 19 - Nephrotic Syndrome

1. Massive proteinuria (>3.5 g/day): Glomerular basement membrane (GBM) is damaged, losing its negative charge and filtration selectivity. Large proteins (especially albumin) leak through into urine.
2. Hypoalbuminemia: Albumin is lost in urine faster than the liver can synthesize it → serum albumin falls.
3. Edema (generalized body swelling): Albumin is the main osmotic protein in blood (oncotic pressure). When albumin falls, oncotic pressure drops → water moves from blood vessels into tissues → edema. Facial puffiness, pedal edema, ascites.
4. Hyperlipidemia (high cholesterol): Low oncotic pressure triggers the liver to compensate by overproducing proteins including lipoproteins (VLDL, LDL) → hypercholesterolemia. Also lipase activity is reduced.

• A/G reversal (0.6:1): As albumin drops and globulins are compensatorily increased by the liver, the albumin/globulin ratio reverses.
• In a child, the most common cause of nephrotic syndrome is Minimal Change Disease (lipoid nephrosis) - excellent response to steroids.

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Slide 20 - Night Blindness (Vitamin A Deficiency)

• The retina has two photoreceptors: rods (dim light/night vision) and cones (color/day vision).
• Rods contain the photopigment rhodopsin = opsin protein + 11-cis retinal (derived from Vitamin A).
• In light: rhodopsin bleaches → 11-cis retinal → all-trans retinal → nerve impulse.
• Recovery (dark adaptation): all-trans retinal must be converted back to 11-cis retinal (requires Vitamin A).
• In Vitamin A deficiency, regeneration of 11-cis retinal is impaired → rods cannot recover in the dark → night blindness.
• Beta-carotene (provitamin A) is converted to Vitamin A (retinol) in the intestinal wall.
• Dietary sources of Vitamin A/Beta-carotene: Mango, carrots, papaya, sweet potato, dark leafy greens, egg yolk, liver, dairy.
• Progressive deficiency also causes Xerophthalmia (dry eyes) → Bitot's spots → corneal ulceration → blindness.

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Slide 21 - Rickets

• Vitamin D (calcitriol/1,25-dihydroxycholecalciferol) promotes absorption of calcium and phosphorus from the intestine, and their deposition in bone.
• Without Vitamin D: Ca and P absorption falls → serum Ca and P are both low.
• Bone mineralization fails → soft, pliable bones that deform under body weight.
• Clinical signs: Bowed legs (weight-bearing deforms soft leg bones), pigeon chest (rib-cage deformity), rachitic rosary (beading of ribs at costochondral junctions), short stature.
• ALP markedly elevated (575 U/L): Osteoblasts (bone-forming cells) are working overtime trying to mineralize bone (using ALP enzyme to cleave phosphate from organic phosphate for deposition). This is a compensatory response, causing a massive rise in serum ALP.
• Treatment: Vitamin D supplementation + calcium, exposure to sunlight (UVB converts 7-dehydrocholesterol to Vitamin D3 in skin).
• In adults, same deficiency = Osteomalacia (softening of bones but no growth plate deformity).

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Slide 22 - Hypothyroidism

• Thyroid hormone (T3/T4) controls the basal metabolic rate (BMR).
• In hypothyroidism, T3/T4 are low → BMR decreases → the body burns fewer calories, generates less heat.
• Symptoms explained:
  • Weight gain: low BMR, less energy expenditure.
  • Cold intolerance: less heat generation.
  • Hoarseness: myxedema (mucopolysaccharide deposits) in vocal cords + laryngeal tissues.
  • Fatigue, lethargy: slowed metabolic processes, reduced ATP production.

• TSH is the most sensitive screening test. A high TSH with low T4 = primary hypothyroidism.
• Treatment: Levothyroxine (synthetic T4).

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Slide 23 - Alkaptonuria

• This is an inborn error of metabolism of the aromatic amino acid phenylalanine/tyrosine.
• Normal pathway: Tyrosine → Homogentisic acid → Maleylacetoacetic acid (enzyme: Homogentisate Oxidase).
• In alkaptonuria: Homogentisate Oxidase is deficient → homogentisic acid (HGA) accumulates.
• HGA is excreted in urine. On exposure to air/sunlight, HGA is oxidized and polymerizes to a black melanin-like pigment → urine turns black (alkapton bodies).
• Benedict's test positive: HGA is a reducing substance (like glucose) → gives positive Benedict's test (brick-red precipitate). Note: this is NOT glycosuria; it is HGA-uria.
• Ochronosis: In adults, HGA deposits in connective tissues (joints, cartilage, sclera, earwax) → dark pigmentation + arthritis.
• This is a benign condition in childhood, but causes arthropathy in adulthood.

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Slides 24 & 26 - Wilson's Disease (Hepatolenticular Degeneration)

Slide 24 (Adult presentation)

Slide 26 (Child presentation)

• Wilson's disease = autosomal recessive mutation in ATP7B gene, which encodes a copper-transporting ATPase in hepatocytes.
• This pump is normally required to export copper from liver cells into bile for excretion.
• Without it, copper cannot be excreted → accumulates in liver, brain (lenticular nuclei = basal ganglia), kidneys, and cornea.

• 90% of serum copper is bound to ceruloplasmin (a carrier protein). When copper cannot be properly incorporated into ceruloplasmin (because the export mechanism is broken), ceruloplasmin levels fall.
• Serum copper is low because copper is trapped in tissues, not circulating.
• But urine copper is HIGH (200 µg/dl in slide 26) - copper that escapes into plasma is filtered by kidneys and excreted.

• Penicillamine: Copper chelator - binds copper and promotes its urinary excretion.
• Zinc: Competes with copper for intestinal absorption; induces metallothionein in gut cells which sequesters copper and prevents absorption.

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Slide 25 - Tetany (Hypocalcemia)

• Calcium plays a critical role in stabilizing nerve and muscle cell membranes. It reduces membrane excitability.
• When serum calcium falls, membrane excitability increases → spontaneous, repetitive nerve firing → sustained muscle contractions (tetany).
• Carpopedal spasm (Trousseau sign): spasm of hand and foot muscles.
• Chvostek sign: tapping the facial nerve near the ear causes twitching of facial muscles.
• Why ALP is normal: ALP rises in rickets (bone turnover) and obstructive jaundice (bile ducts). Normal ALP here means bones are NOT being demineralized (this is not rickets or bone disease causing the hypocalcemia).
• Normal albumin rules out hypoalbuminemia as the cause of low total calcium (albumin binds calcium; low albumin gives falsely low total Ca but ionized Ca is normal).
• Likely cause: Hypoparathyroidism (low PTH → low Ca, high phosphate). PTH normally raises Ca and lowers phosphate.

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Slide 27 - Gout

• Uric acid is the final breakdown product of purines (adenine and guanine from DNA/RNA).
• Purines → xanthine → uric acid (via xanthine oxidase enzyme).
• Non-vegetarian diet = high purine intake (meat, seafood, organ meats are rich in nucleoproteins).
• When uric acid levels exceed solubility (~6.8 mg/dl), it crystallizes as monosodium urate (MSU) crystals.
• Crystals deposit in joints (especially big toe = podagra), synovial fluid, and soft tissues (tophi).
• Crystals trigger neutrophil infiltration and inflammation → acute gouty arthritis (intense joint pain, redness, swelling).
• Urinary uric acid is elevated (2.5) - actually in this case it is high in urine too (above normal 0.5-0.7), but inadequate relative to the high production, so blood levels remain elevated.
• Treatment: Allopurinol (xanthine oxidase inhibitor - reduces uric acid production), colchicine (acute attack), probenecid (increases uric acid excretion).

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Slide 29 - Lesch-Nyhan Syndrome

• X-linked recessive disorder (affects males almost exclusively).
• Purines are normally salvaged and recycled. HGPRTase is a salvage enzyme that converts hypoxanthine and guanine back into IMP and GMP for reuse.
• Without HGPRTase: hypoxanthine and guanine cannot be salvaged → they are broken down to uric acid.
• Massive accumulation of uric acid → severe hyperuricemia (11 mg/dl) → gout, kidney stones, nephropathy.
• Neurological features: HGPRTase is critical for purine synthesis in the brain. Deficiency causes neurological dysfunction:
  • Spasticity and choreoathetosis.
  • Self-injurious behavior (self-mutilation: biting of fingers, lips, tongue) - pathognomonic feature.
  • Intellectual disability.
  • Aggressive behavior.
• Difference from gout: Gout is an acquired disease in middle age. Lesch-Nyhan is a congenital inborn error with severe neurological involvement and presents in infancy/early childhood.
• Treatment: Allopurinol controls uric acid but does NOT reverse neurological features (HGPRTase cannot be replaced pharmacologically for the brain).

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Quick Diagnostic Summary Table