PBL 6 – HIDDEN ON THE CRYPTS
1998 Paper 3, Part E: Q1, 3
Question 1. (5 marks)
You are an intern in Townsville Hospital, where one of your patients is an 11-year old Aboriginal boy who was flown in from Palm Island after breaking his forearm while playing around with friends. Three days after he is admitted to your unit, the nursing staff tell you that he has been complaining of low-grade epigastric discomfort, and has had intermittently loose stools. On being questioned further by you, he says that he has had these symptoms on and off perhaps for a month or more this time, but that they don't really bother him, as he's had them before. You request that faecal microscopy be done, and the following day the report comes back that no parasites were found (and faecal culture after 2 days failed to grow pathogenic bacteria).
Respond to the following statements as TRUE (T), FALSE (F), DON'T KNOW (D):
CIRCLE YOUR CHOICE
1. This presentation is consistent with giardiasis, but is not
sufficiently specific to exclude other possibilities. T F D
2. In a child of this age from a highly endemic area, it is likely
that giardiasis would be asymptomatic, and other possibilities should
be seriously considered. T F D
3. If his full blood examination showed a haemoglobin level of 90 gm/L,
and a total white cell count of 11,000/μL, of which 10% were
eosinophils, this would be consistent with a diagnosis of hookworm
infection. T F D
4. If hookworm infection were the underlying problem here, explaining
the anaemia and eosinophilia, the laboratory should have found
typical eggs in the boy's faeces. T F D
5. Strongyloidiasis can present with these clinical features and
laboratory findings. T F D
6. Strongyloidiasis is readily diagnosed by finding typical eggs in fresh,
faecal concentrates. T F D
7. Pinworm infection (enterobiasis) would be consistent with all of the
above findings. T F D
Question 3.
List the major social and behavioural factors that underlie the unacceptable high mortality and morbidity in the Indigenous population. (5 marks)
Poverty, substance abuse, unemployment, access to health care, perception of health, domestic violence
1999 Paper 2, Part C: Q4, 6
Question 4.
List five (5) transmission routes for the spread of microbial pathogens.
1. Respiratory / salivary spread (aerosol / saliva)
2. faecal-oral spread
3. venereal spread
4. vector (biting arthropod)
5. blood transmission (needles)
Joan asks if she should tell the day-care that her son has chicken pox.
Question 6.
List two (2) public health benefits of Joan informing the day care centre that her son has chicken pox.
1. Precautions can be taken by the staff of the day care to protect themselves and other children from the virus (e.g. cleaning toys used by the child, disposing of any food left by child)
2. Allow the child care center to determine the incidence / prevalence of the disease as under certain circumstances (such a certain number of children contracting a particular virus) they are required to inform the government.
1999 Paper 3, Part B: Q9-10
Question 9.
List four (4) socio-environmental factors that may contribute to the high rates of otitis media and chronic suppurative otitis media in Aboriginal and Torres Strait Islander children.
1) Poor access to health
2) Distrust of western healthcare system – many people go to doctor / hospital and not return, prefer traditional treatments.
3) Living conditions can be poor
4) Poor nutrition
5) Lack of education about available resources
Question 10.
In Australia, Indigenous people have higher rates of mortality than non-Indigenous people. List the four (4) disease groups that cause the highest rates of mortality in Indigenous people.
1. Diabetes
2. Mental Illness
3. Cardiovascular
4. Cancer
1999 Paper 3, Part F: Q1-5
No paper supplied, just answers.
1. 1. osmotic diarrhea
2. chronic diarrhea
3. noninflammatory diarrhea
4. secretory diarrhea- typically very watery and does NOT stop when fasting
Acute diarrhea is that which last for < than 4 weeks.
Inflammatory diarrhea contains blood.
Note that the definition of diarrhea can vary from person to person and that a normal bowel frequency can be from 3 times a day to 3 times a week. A normal daily stool weight on a Western diet is 100-200 grams/day.
2. D- Fatty acid concentration decreases.
K+ is pumped into the lumen in exchange for Na+.
Na+ levels drop as it is absorbed by active and passive mechanisms. Na+ is absorbed by symports for amino acids, glucose (SGLUT), etc. in the jejunum. Na+ can be actively absorbed throughout the intestinal tract.
HCO3 is secreted to aid in neutralizing the acid generated by fermenting anaerobic bacteria.
Fatty acids combine with bile salts to form micelles which are then absorbed.
Osmotic concentration drops as nutrients and salts are absorbed.
3. B. Osmotic because Na+ and K+ be major contributors to the mOsm of the feces.
4. E
5. A) plicae circulares
B) simple columnar epithelium with goblet cells
C) crypt of Lieburkuhn
D) Paneth cell (cell of a crypt)
E) muscularis mucosae
F) submucosal gland (Brunner’s gland)
2000 Paper 2, Part C: Q1
Joanne B aged 43 years, is an Aborigine who lives in an indigenous community near Weipa, North Queensland.
Question 1. (6 marks)
(a) List the six (6) leading categories of illness that contribute to the mortality of Indigenous Australians. (3 marks)
IHD, diabetes, stroke, cancer, respiratory disease, other heart disease
(b) List six (6) of the major social or behavioural factors that contribute to the mortality and morbidity patterns found in the indigenous population. (3 marks)
Poverty, substance abuse, unemployment, access to health care, perception of health, domestic violence
2000 Paper 3, Part B: Q1-6, 8, 9
A mother comes to your suburban general practice, bringing her 2-year old daughter Chloe, who has had diarrhoea for 3 days. The mother, who works as a nurse in a convalescent hospital, says that there is an epidemic of diarrhoea at the local kindergarten that Chloe attends 3 half days per week, and that it is typical of “Giardia.” She requests treatment for her daughter.
Question 1. (3 marks)
List three (3) categories of organisms that could be responsible for institutional outbreaks of diarrhoea. Give one (1) example of an organism from each category.
Viruses eg. Rotaviruses
Bacteria eg. Campylobacter
Protozoa eg. Giardia
Question 2. (3 marks)
(a) List the typical clinical features of an acute Giardia infection in children. (2 marks)
- Diarrhea that is foul smelling
- Dehydration and malabsorption
- Abdominal pain and cramping
- Symptoms not usually lasting 2 days
(b) Is it possible to diagnose the responsible organism by the clinical presentation? Explain your answer. (1 mark)
No, because there are several very prevalent organisms that may cause diarrhea. Initial symptoms give a guide but cultures and/or fecal examinations should provide more information.
Question 3. (2 marks)
(a) What is the route of transmission of giardiasis? (1 mark)
Faecal-oral. And can be found in drinking water.
(b) Comment on the distribution of giardiasis in the Australian community. (1 mark)
Giardia is common in areas of low sanitation and poor quality of drinking water. It is endemic in the aboriginal population.
Question 4. (3 marks)
Explain the physiological mechanisms by which infection with Giardia intestinalis may cause diarrhoea.
Giardia may coat the entire lining of the GIT wall and cause malabsorption of nutrients through damage to the brush border. This causes increases in the osmotic pressure into the lumen. Giardia also secretes a cytopathic substance that can cause villous atrophy, affecting the maturity of the epithelial cells. This causes an increase in the proportion of immature secretory type epithelia and a decrease in the mature absorptive epithelia.
Question 5. (3 marks)
How is giardiasis detected by pathology laboratories?
Giardiasis is detected by finding cysts within the stool. Usually, three seperate stool samples are tested because secretion of giadiasis cysts can be intermittent. Cysts are seen under a light microscope. Duodenal fluid may also be examined for cysts. And a specific antigen may be identified in the fecal sample.
Question 6. (2 marks)
How sensitive and specific is the test you described in question 5?
Because you get no false positives in the test, the test is very sensitive. If you find the cysts, the patient has giardia. The test not very specific however because it can be difficult for the lab to find the cysts, the cysts may not be present within that specific sample, or the patient may have giardia but not excreting cysts at all.
Question 8. (3 marks)
What is the natural history of giardiasis in an otherwise healthy child, who does not receive specific treatment?
The child who develops giardiasis will develop symptoms 12 - 14 days after exposure. In some patients this may involve gastric pain and diarrhea but in others may be asymptomatic. In a healthy child, the parasite may be removed from the patient within a couple of weeks or it may persist for months or years. Giardia may become asymptomatic and the patient may just shed cysts or the patient may continue to have diarrhea, with associated Wastage and malabsorption.
Question 9. (4 marks)
The National Health and Medical Research Council guidelines recommend that children with diarrhoea be excluded from child care centres until their diarrhoea has ceased and they are well.
(a) List two (2) reasons for this recommendation. (2 marks)
- Many of the causes of diarrhea are highly infectious and having diarrhea assists transfer.
- With the close contact of infected child with other children and staff, there are many
opportunities for infection transfer especially given children are not always hygenic.
(b) In addition to excluding the child from daycare until he/she is well, list two (2) measures that a child care centre should take if there is a child with diarrhoea in the centre. (2 marks)
- Exclude the child from child care facilities
- Ensure good handwashing and cleaning procedures are maintained
2001 Paper 2, Part A
A 3 year old boy Sam G was brought to you by his mother. She is concerned that he has frequent loose bowel motions which are foul smelling, bulky, and difficult to flush away. She is also concerned that he tires easily and seems small for his age despite having a hearty appetite. You examine Sam. You notice several bruises over his legs and trunk and he appears pale.
His height is 94cm (25th centile) and weight 10.4 kg.
Question 1. Refer Growth Chart on next page. (5 marks)
(a) Describe the growth (centile) chart. (1.5 marks)
Growth charts plot weight, height and expected head circumference against age. They consider the range of growth as expressed in percentiles.
(b) At what age should concern have been raised regarding this child’s weight?
I don’t actually have a copy of his chart concern should have been raised when he was 2 standard deviations away from the mean of when there was a significant decrease in his growth progress.
(c) List three (3) broad hypotheses that could explain the pattern of weight gain recorded in this weight chart. (3 marks)
Malabosorption- Intraluminal surface cell abnormalities→decreased surface area to absorb food
Malnutrition- Not getting all the necessary nutrients from his diet.
Defective motility- Decreased interstitial transit time therefore less time to absorb food.
Question 2. (3 marks)
Give one (1) mechanism (a series of steps) linking pallor with Sam’s gastrointestinal
symptoms.
Decreased Fe→decreased Haem→microcytic anemia
Decreased folate/B12→dereased DNA synthesis→decreased protein synthesis→ immature nuclear chromatin→ megablastic anemia
Question 3. (4 marks)
Give one (1) mechanism linking bruising with Sam’s gastrointestinal symptoms.
Vitamin K deficiency → decreased clotting factor production (9,7,2,10)→therefore decreased clotting → increased haemorrhage →increased bruising.
Question 4. (3 marks)
Suggest three (3) possible tissue or cellular changes that could affect the small bowel mucous membrane in this patient.
Decreased villi, Transformation of columnar to cuboidal, necrosis of GI epithelium.
Question 5. (4 marks)
Sketch a cartoon showing the layout of ion transportation in a cell secreting into the gut.
Question 6. (4 marks)
Describe the mechanism (a series of steps) of diarrhoea which is likely in this case.
Inability to absorb nutrients which remain in the lumen e.g. glucose→ osmotic effect→water drawn into lumen→diarrhoea
Question 7. (7 marks)
The three phases in the absorption of a macronutrient from the gut are:
(a) luminal digestion;
(b) absorption of digestive products by gut epithelial cells; and
(c) mucosal clearance.
Briefly describe how each of these phases applies to the absorption of dietary triglyceride.
(a) Luminal digestion (2 marks)
Bile salts emulsify TAGS into lipid emulsions increasing surface area available to pancreatic lipase which then breaks down fatty acids and monoglycerol.
(b) Absorption of digestive products (3 marks)
FA and MG incorporated into centre of micelles which is formed by bile salts and cholesterol. FA and MG then able to diffuse into cell
(c) Mucosal clearance (2 marks)
Inside GI cell FA and MG reforms into TAGs which form chylomicrons which leave the cell by exocytosis and enter the lymphatics for transport to other parts of the body.
2001 Paper 3, Part E: Q1
You have recently joined a group general practice in a Brisbane suburb. As a
newcomer to the area, you were eager to find out some information about the suburb and obtained the following ‘community profile’ information from the Australian Bureau of Statistics website. You also obtained the same information for Brisbane overall.
This information is summarised in the table below.
Question 1. (5 marks)
(a) What does this information suggest regarding the level of social advantage /
disadvantage in your suburb, and why? (3 marks)
Suggest population is strongly social-economically disadvantaged. This is because compared to the population average, there is (index of relative social economic disadvantage)
· Higher percentage of single parent families