BGDB End-of-Course Tutorial

1. BGDB End-of-Course Tutorial Sam and Arty

2. Tonight… • Approaching the End of Course Exams • Gastroenteritis • Gut Physiology • Thyroid Physiology • Depression • Normal Development • GIT Embryology • Wrap-up and Questions www.medsoc.org.au

3. Approaching the End of Course Exam • Read the question • Define key concepts • Structure (Logical Flow) • Tables & Diagrams • Dot points • Completely lost? Write what you know www.medsoc.org.au

4. Gastroenteritis A 5 yro child presents to the ED with symptoms of diarrhoea, vomiting and nausea. • What is gastroenteritis? • What are the common causative agents of gastroenteritis? • How would you make a diagnosis? • How would you manage this case?

5. Defining Gastroenteritis • Inflammation of the GIT. • Involving stomach/SI • Diarrhoea, vomiting, malaise, nausea, abdominal discomfort.

6. Causative Agents-viral • In Australia: viruses, bacteria, parasites • Norovirus: most common in adults. • Rotavirus: Second most common in children. Vaccine. • Adenovirus: Most common in children • Astrovirus, picornavirus, parvovirus, sapovirus

7. Causative Agents - bacterial • Campylobacter jejuni: most common in Aust. Zoonotic potential. • Salmonella non-typhoid: second most common. Food poisoning. • Salmonella typhoid: s. Typhi, s. Paratyphi. Longer lasting, systemic • Shigella: very low infectious dose. faecal/-oral, sexual • Vibrio cholera: ‘rice water stools’

8. Causative agents - parasites • GiardiaLamblia: protozoan. • Symptoms - flatulence, foul smelling stools, weight loss, diarrhoea, constipation. Metronidazole.

9. Diagnosis • Exclude other possibilities (eg. medications) • Blood tests – FBC, inflammatory markers(CRP, ESR) • Stool sample: microscopy & culture • If bacterial/parasite microscopy & culture will help detect

10. Management • Diet/Nutrition • Rehydration • Adsorbents: eg. activated charcoal • Antimotility drugs: eg. loperamide, atropine • Bismuth subsalicylate: anti-inflammatory • Intestinal flora modifers • Anti-microbials: shigella, severe cholera, typhoid salmonella

11. Sample Question • Antony has just eaten a sugar-heavy meal. Describe the mechanism by which the sugars in the food are broken down and absorbed across the gastrointestinal lining.

12. What are the components of the process? • Digestion • Mouth (Salivary Amylase) • Pancreas (Pancreatic Amylase) • Small Intestine (Disaccharidases) • Absorption (transport across the enterocyte into the bloodstream)

13. Digestion • Salivary amylase breaks down complex sugars (eg. starch) into simple sugars • Pancreatic amylase further breaks down complex sugars • Disaccharidases break down disaccharides into monosaccharides • Lactase (Lactose  Glucose + Galactose) • Maltase (Maltose  2 * Glucose) • Sucrase (Sucrose  Glucose + Fructose)

14. Absorption • Across the enterocyte apical membrane • Na+/Glucose Co-Transporter (SGLT1) for Glucose and Galactose • GLUT5 for Fructose • Across the enterocyte basal membrane • GLUT2 • Gradients maintained by the Na+/K+ ATPase

15. Diagrams!

17. Thyroid Physiology

18. Effects of Thyroid Hormone • Increase basal metabolic rate: glycogenolysis, gluconeogenesis, lipolysis, protein synthesis. Heat generation, increased energy usage, oxygen consumption. • Growth effects: with GH • Cardiac effects: increase contractility • Developmental effects: neonatal CNS

19. Thyroid – clinical perspectives • A 20yro patient presents with symptoms of fatigue, muscle weakness, cold intolerance, bradycardia, hypoglycaemia, constipation. • Is this more likely to be hypothyroidism or hyperthyroidism? Why? • Describe two causes of hypothyroidism • How would you manage a patient with hyperthyroidism?

20. fatigue, muscle weakness, cold intolerance, bradycardia, hypoglycaemia, constipation • Increase basal metabolic rate: glycogenolysis, gluconeogenesis, lipolysis,protein synthesis. Heat generation, increased energy usage, oxygen consumption. • Growth effects: with GH • Cardiac effects: increase contractility, HR • Developmental effects: neonatal CNS

21. Causes of Hypothyroidism • Definition –abnormally low level of TH • 3-5% of the population. Women, age • Hashimotosthyroiditis: inherited autoimmune • Pituitary or hypothalamic disease • Thyroid destruction • Medications • Severe iodine deficiency

22. Managing Hyperthyroidism • Surgery • Radioactive iodine • Anti-thyroid drugs

24. Lumen

26. Anti-Thyroid Drugs • Carbimazole – inhibits thyroid peroxidase • Propyl-Thiouracil (PTU) – inhibits thyroid peroxidase & blocks de-iodination of T4 to T3 • More T4 produced. But T3 more potent at target

27. Depression • Anhedonia • Sleep Changes • Appetite and weight changes • Dysphoria (low mood) • Fatigue • Agitation (psychomotor) • Concentration (loss of) • Esteem (decreased self-esteem) • Suicidal Ideation

28. Example • Mrs X is a 55-year-old South Sydney Rabbitohs supporter, who has come in complaining of a four-week history of tiredness and ‘just not feeling like doing anything’. You suspect she may be depressed. • What questions could you ask Mrs X in order to help support a diagnosis of depression?

29. Answering the Example Question • Work through ASADFACES! • Establish Chronicity!! • Discuss risk factors if relevant

30. Management • Non-pharmacological methods! • Pharmacological agents (name, class, mechanism of action, side effects) • Electroconvulsive therapy

31. Pharmacological Management of Depression • Selective Serotonin Reuptake Inhibitors (SSRIs) • Monoamine Oxidase Inhibitors (MAOIs) • Other (Venlafaxine, Buproprion)

32. Developmental Milestones • A mother brings in her 2yro son, Michael, who has Down Syndrome. He said his first word last week, and although can crawl and cruise, has not yet started to walk. • Is this normal? Why/why not? • What is developmental delay? What could cause it? • How would you assess this case?

33. Domains of Normal Development • Gross Motor • Fine Motor • Cognitive (Piaget’s Theory) • Personal/Social • Speech/Language

34. Normal Developmental Milestones • 6weeks: primitive reflexes • 9months: sit alone, object permanence • By 12months: pull to stand, precise pincer grip, first word • By 2years: run, two words at two. • 3years: tricycle, upstairs, mature pencil grip, use scissors, tower of 9 blocks, cooperative play, know gender, draw circle, understand 3keyword instructions • 6years: skip, bounce and catch ball, write first name, know address.

35. Michael’s development • Down syndrome – can delay development • Michael’s case: reaching his milestones later • Need to assess cases individually, and realise some range is normal

36. Developmental delay and its causes • The failure to meet developmental milestones at expected periods. Global or Domain-Specific. • Mental retardation, CNS problems (meningitis) • In Utero: infection in womb, FAS, trauma • Chronic infection: deafness/glue ear (gentamicin) • Hormonal problems-eg. thyroid • Genetic/Family history-eg. DS, Turner • Idiopathic • Nutritional problems

37. Assessing developmental delay • observe child • detailed history • check milestones • physical neurological exam • developmental screening: eg. parents evaluation of developmental status (PEDS),

38. How to learn GIT Embryology • By time points • By organs • Pay attention to abnormalities mentioned in the lecture!

39. GIT Embryology Time Points • Week 3 – GASTRULATION (formation of the three germ cell layers) and FOLDING (around the notochord) • Week 4 – Segmentation of Mesoderm (Paraxial, Intermediate, Lateral Plate – Splanchnic + Somatic), Formation of Foregut, Midgut and Hindgut • Week 5 – 8 Recanalization. • Weeks 8-10 Intestinal Rotation

40. GIT by Organ • Liver • Stomach (including rotation) • Pancreas • Spleen • Learn about which germ cell layer, and key phrases (eg. Dorsal mesogastrium for spleen, septum transversum for liver)

41. GIT Abnormalities • Oesophageal atresia (recanalization) • Meckel’s diverticulum (improper closure of the vitelline duct)

42. Wrap Up & Questions