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Flashcards in 2011 A Remembered Deck (63):
1

Which of the following immunomodulators is most commonly associated with gum hypertrophy and hypertrichosis?

A. Azathioprine
B. Cyclosporin
C. Methotrexate
D. Mycophenolate
E. Tacrolimus 

Azathioprine – GI, myelosupression, alopecia

Cyclosporin - gingival hyperplasia, convulsions, peptic ulcers, pancreatitis, fever, vomiting, diarrhea, confusion, hypercholesterolemia, dyspnea, numbness and tingling particularly of the lips, pruritus, high blood pressure, potassium retention possibly leading to hyperkalemia, kidney and liver dysfunction (nephrotoxicity[23] and hepatotoxicity), hirsutism, burning sensations at finger tips and an increased vulnerability to opportunistic fungal and viral infections.

Methotrexate – GI, mouth sores, myelosuppression, alopecia

Mycophenolate – GI, myelosuppression

Tacrolimus – HTN, renal toxicity, electrolyte imbalance, hyperglycaemia/diabetes, encelopathy, seizures

2

QUESTION 2
Situs inversus is most commonly associated with which of the following?

A. Absent thymus

B. Asplenia

C. Bilobed right lung

D. Complete heart block

E. Polysplenia

Answer C. Bilobed right lung

Normal positioning of heart and organs is termed situs solitus.
Situs inversus totalis - complete mirror image of internal organs, with spleen intact. Right lung bilobed due to dextrocardia.
Different types of situs inversus....totalis = heart and organs, thoracalis = thorax only (heart and lungs), abdominalis = abdominal organs only (heart intact).

There is also left and right isomerism, where named side of the chest is duplicated in mirror image on alternate side. So, left isomerism is associated with polysplenia due to positioning of spleen on left and right sided isomerism is associated with asplenia for the same reason.
 

3

A woman comes to see you who is a regular patient of yours. She is pregnant and has asked for advice concerning SIDS, because her sister’s child died at the age of 3 months of SIDS.

Regarding SIDS, which of the following has not been shown to reduce the risk of SIDS?

A. Breastfeeding.
B. Sleeping in the supine position.
C. Sleeping in an individual cot / bassinet.
D. No smoking in household.
E. Apnoea monitor for first 12 months of life. 

E. Apnoea monitor for first 12 months of life.

4

The Autism diagnostic observation schedule (ADOS) is a tool used in the assessment and diagnosis of autism. The following results were obtained in a study of ADOS as a diagnostic tool:

According to this table, what is the positive likelihood ratio?
A. 1
B. 2
C. 8
D. 36
E. 4

Answer C. 8

Positive Likelihood ratio =  sensitivity/1-specificity

Sensitivity = true positive [80]/(true positive+false negative) [80+20] =0.8

Specificity = true negative [810]/(true negative + false positives) [810+90] = 0.9

sensitivity/1-specificity = 0.8/1-0.9 = 8
 

5

Which is the principle component of the immune system responsible for the initial response to virally infected cells?
A. HLA class I
B. HLA class II
C. Complement
D. B-cells
E. Immunoglobulin
F. NK cells

 

Answer F. NK Cells

From Immunology text....Basic Immunology: Functions and Disorders of the Immune System

Virus defense is special type of host defense that involves interferons, NK cells. Interferons (INF 1) are secreted by virus infected cells and trigger surrounding cells to inhibit viral replication. IFN 1 also enhance ability of NK cells.


Innate immunity - First line response to microbe exposure. Immune responses present from birth and not adapted in response to microorganism exposure. Includes physical barriers, enzymes in epithelial and phagocytic cells, cells that release cytokines (macrophages, mast cells, NK cells), complement, CRP, MBL.

NK Cells (Innate immunity) are a class of lymphocytes that recognises infected cells and kills them by secreting a macrophage-activating cytokine. Activated within 12 hours of infection.

Adaptive immunity - B and T cell response, regulated by T cells.

T cells - naive T cells recognise antigens presented by MHC which stimulate proliferation and differentiation into effector and memory T cells. CD4 T cell recognises class II MHC which present antigens ingested from extracellular microbes. CD8 T cell recognises class I MHC which present peptides from cytosolic or nuclear antigens.

B cells - naive B cells express two membrane bound immunoglobulins - IgM and IgD that are antigen receptors. When activated, these B cells undergo clonal expansion (proliferation into antigen-specific cells) and differentiate into plasma cells which actively secrete antibodies.

Complement (Innate and adaptive immunity)- may be activated by the alternative pathway by proteins on the microbe (innate immunity), or by the classical pathway (adaptive) by antibodies binding to microbes. May also be triggered by mannose-binding lectin (lectin pathway) binding to microbe and triggering the proteins of the classical pathway but because no antibodies are activated it is still considered innate immunity.

6

(similar to Q in 2010 remembered paper (Erickson Stages) but not completely the same. I couldn’t remember all the answers and copied the ones from 2010 but A and E definitely were the same. One answer included something vs sexuality and another one included abstract thinking vs something else.)

An adolescent with type 1 Diabetes Mellitus is being transferred to an adult model of care. Which is the most important psychological challenge that must be dealt with to ensure a successful transition?

A. Identity vs confusion
B. Initiative vs Guilt
C. Autonomy vs shame and doubt
D. Industry vs inferiority
E. Intimacy vs isolation 

A. Identity vs confusion

Infancy (0-18m) = Trust Vs mistrust
Toddler (18m -3) = Autonomy Vs shame
Preschool (3-5) = Initiative Vs guilt
School age (5-13) = industry vs inferiority
Adolescence (13-18) = Identity vs role confusion
Young adults = Intimacy Vs isolation

7

Helicobacter pylori resistance to antibiotic is an increasing problem worldwide. Which of the following antibiotics, which has been used in combination treatment, has the highest incidence of resistance in treatment naïve patients with H. pylori?

A. Amoxicillin
B. Clarithromycin
C. Metronidazole
D. Tetracycline
E. Ciprofloxacin
 

Answer C. Metronidazole
From eTG.....metronidazole resistance in Australia is 50%, clarithromycin resistance is 5-7%.

First line eradication therapy is PPI + amoxycillin + clarithromycin

8

In neonatal allo-immune thrombocytopenia, what is the most common human platelet antigen (HPA) sensitisation in the Caucasian population?

A. 1a
B. 2
C. 3a
D. 4
E. 5b
 

Answer A. 1a

Anti-HPA 1a =75%
Anti-HPA 5b = 16%
Anti-HPA 15b = 4%

Neonatal alloimmune thrombocytopenia occurs when fetal platelets contain an antigen inherited from the father that the mother lacks. The mother forms IgG antiplatelet antibodies that cross the placenta and destroy fetal platelets resulting in fetal and neonatal thrombocytopenia. Maternal antibodies cross the placenta in early midtrimester. Risk of intracranial haemorrhage (10-20% of affected newborns). Can occur in 1st pregnancy and subsequent pregnancies more severe.

9

In B cell non-Hodgkin lymphoma what is the most likely site of primary organ involvement?
All remembered options included below...
NB: One candidate remembered as non-Hodgkin NON-B cell type.
A. Bone
B. Skin
C. Mediastinum
D. Intestine
E. Thymus
F. Tonsils
 

Answer D. Intestine

B cell-B for BELLY
T cell - T for Thorax

Non-Hodgkin lymphoma is fifth most commonly diagnosed childhood cancer. Median age of diagnosis is 10 years and risk increases with age. Most common subtypes are from B cell progenitors, but can also be T cell progenitors, mature T or B cells. In childhood NHL usually high grade and aggressive.

B-cell lymphoma most commonly refers to Burkitt’s Lymphoma, a type of small non-cleaved non-hodgkin’s lymphoma.  Endemic-type in Africa presents with head and neck disease, but in Australia – “The nonendemic (sporadic) form usually has an abdominal presentation, most often with massive disease and ascites, involving the distal ileum, stomach, cecum and/or mesentery, kidney, testis, ovary, breast, bone marrow, or central nervous system. Presenting symptoms can include those related to bowel obstruction or gastrointestinal bleeding, often mimicking acute appendicitis or intussusception” – UTD

It may refer to diffuse large B-cell lymphoma, but as per UTD (Patients with DLBCL typically present with a rapidly enlarging symptomatic mass, most usually nodal enlargement in the neck or abdomen) the answer is probably the same.

If non-B type (ie. T-cell) - mediastinum.

10

The following graph shows a variety of drugs effect at different concentrations:

Which of the following statements is true?
A. Drug A is more potent then Drug D
B. Drug A and Drug B have equal potency
C. Drug B is a partial agonist
D. Drug C is a complete agonist
E. Drug C and Drug D have equal efficacy
 

Answer E. Drug C and D have equal efficacy

Drugs A and B are equally effective and complete agonists (100%). Drugs C and D are also equally effective (50%) and partial agonists. Drug D is the most potent (less concentration required for effect) and drug C least potent.

11

Children with haemolytic disorders are at risk of iron overload as they require multiple transfusions. The recommended daily intake of iron for children is 1mg/kg/day. What is the amount of elemental iron in a single unit of packed red bloods cells?

A. 5mg
B. 50mg
C. 200mg
D. 500mg
E. 1000mg 

C. 200mg

One unit is approximately 220mL. When donated, it is tested for: HIV/AIDS, hepatitis B, hepatitis C, Human T-cell Lymphotropic Virus- HTLV and syphilis.

12

Which part of the brain is most vulnerable to the effects of hypoglycaemia in the newborn period?

A. Frontal lobe.
B. Hippocampus.
C. Parietal lobe.
D. Occipital lobe.
E. Temporal lobe.

Answer D. Occipital lobe

Transient, isolated hypoglycaemia of short duration does not appear to result in any significant sequelae, but don’t forget that GLU not only supplies fuel to the brain, but also membrane lipids for things like myelin, thus in prolonged hypoGLU, these are used at the expense of brain growth.

The neonatal liver has a reduced ability to produce ketones, especially in the setting of hyperINS (as in the setting of hypoGLU from maternal GDM), thereby denying the brain an alternative fuel.

Permanent neurological sequelae occur in 25-50% with severe, recurrent hypoGLU (under 6m age). These are characterised by;

  • Atrophic gyri
  • Reduced myelination in cerebral white matter
  • Atrophy in cerebral cortex
  • MOST COMMONLY PARIETAL AND OCCIPITAL LOBES

(predominantly a posterior pattern)
No infarcts if HIE did not also occur. The cerebellum is always spared if only insult was hypoGLU.

13

A two-year-old boy presents with a six week history of diarrhoea and lethargy. On clinical examination
he has peripheral and periorbital oedema. Investigations are as follows:

Liver function tests normal except for Albumin 22g/L.
Coagulation studies normal.
Urinalysis normal.

Which faecal test is most likely to reveal the cause of his presentation?

A. Alpha-1 antitrypsin (non digested protein)
B. Proalbumin
C. Chymotrypsin
D. Elastase
E. Tryptase

A. Alpha-1 antitrypsin (non digested protein)

Normal urinalysis in setting of peripheral oedema suggests protein losing enteropathy, especially given the history of diarrhoea, not a nephritic history.

Best test for PLE is faecal alpha-1-anti-trypsin. A1AT has a similar size to albumin (67kDa molecular mass) and is resistant to digestion in the GIT.

Causes of PLE include; celiac, inflammatory bowel disease, SGSyndrome, intestinal lymphangiectasia, amyloid and infection, typically Giardia.

  • C – chymotrypsin (a gut proteolytic) is released as inactive chymotrypsinogen, cleaved by trypsin
  • D – faecal elastate reflects exocrine pancreatic insufficiency (chronic pancreatitis, CF) but falsely raised in acute diarrhoea
  • E – elevated tryptase implies a colitis. Not to be confused with serum trypsinogen (increased in CF pancreatic exocrine insufficiency)

14

QUESTION 14
A Newborn Screening result is reported as TSH 20mU/L. This would correspond to a plasma TSH of:

A. 10mU/L
B. 20mU/L
C. 40mU/L
D. 60mU/L
E. 80mU/L

Answer C. 40mU/L
Per lab at RCH

  • To convert from gurthrie card TSH to serum/plasma TSH multiply by 2.2
  • So TSH 20 on Guthrie would correspond to plasma TSH of 44 at that time

15

The Southern Hemisphere seasonal Influenza vaccine (including H1N1) is best described as which of the following:

A. live attenuated
B. polysaccharide conjugate
C. protein subunit
D. killed whole
E. toxoid 

Answer C. protein subunit

IM is an inactivated (trivalent) split and purified, inactive vaccine containing the HAEMAGGLUTININ and NEURAMINIDASE protein subunits of each type.
 

16

A 4 week old baby presents with an erythematous rash to the face and arms. A diagnosis of neonatal lupus is made. Which of the following antibodies is the most likely to be positive:
A. Anticardiolipin antibody
B. Anti dsDNA
C. Anti skin basement membrane antibody
D. Anti scl70
E. Anti-SSA/Ro

Answer E. Anti-SSA/Ro

Heart block can manifest later (2-3 months) because it is a scarring process of the AV node that might take time to develop. Complete heart block = ventricular escape rhythym. AV dissociation

Neonatal lupus:

  • Anti-Ro = Sjogren’s & heart block, -La = rash
  • This is neonate who gets disease manifestations because of mum’s antibodies – the manifestations can be transient or permanent:
  • Note that mum may not have had manifestations herself, or she may have Sjogren’s rather than SLE
  • The transfer of Anti-SSA/SSB (Ro/La) occurs between 12-16w gestation.
  • Cutaneous lesions occur around 6w (4w in this question) after exposure to UV light. 25% of rashes scar!
  • If congenital heart block occurs, it is permanent and may require pacing.
  • Disease activity: C3
  • Specific: Anti-SM (Smith)
  • Sensitive: ANA
  • Neonatal lupus: Anti-SSA/Ro

Transient manifestations(

  • Discoid lesions +/- other manifestations of SLE (rash appears over few days – with exposure to light)
  • DCT +ve AIHA, thrombocytopenia, leucopenia
  • Myasthenia gravis
  • Neonatal hepatitis
  • Positive ANA serology, reduced complement

Permanent manifestations

  • CHB without other signs of SLE
  • Endomyocardial fibroelastoisis
  • PDA, septal defects

NOTE

  • Vast majority of children born to SLE mothers are normal (90%)
  • And if they have neonatal SLE most will require no therapy
  • May predate maternal manifestations.
  • Placental transfer of anti-Ro/anti-La antibodies from ~18/40
  • Anti Ro will be +ve 80% of the time.
  • Ro Ab has been demonstrated in fetal myocardium.
  • If mother has high levels of antibodies
    • 10% chance of neonatal lupus
    • 50% skin (malar rash, erythema annulare)
    • 50% cardiac manifestations (CHB+/-Hyrdops-AV node fibrosis, permanent)
    • thrombocytopenia
    • elevated bilirubin
    • not all subsequent pregnancies will be affected (~25% - higher risk)
  • Anticardiolipin is a RF for recurrent miscarriage

Investigations

  • ANA (FANA test)
    • Often present.(Sensitive,nonspecific)
    • If repeatedly neg, SLE unlikely as 97% +ve at some stage.
    • Also raised in Drug Induced LE, Dermatomyositis, Juv Arthritis, Vasculitis, Scleroderma, EBV, CAHep, Hyperextensisbility, IgA def, and 20% of normal(up to 1/640).
    • ?The likelihood of rheumatic or autoimmune disease is high in children with +ve ANA.
  • DS DNA
    • more specific, levels reflect disease activity.
    • Anti DS DNA and Low C3 is 100% SLE specific
  • CH50,C3,C4
    • decreased in active disease.
  • Anti Smith
    • Only found in SLE. Does not measure activity.
  • Hypergammglobulinaemia
    • frequenly assoc.
  • Anti RNP
    • seen in mixed CT picture.
    • If pos but neg DS DNA, low risk of nephritis.
  • Anti Ro (SS-A)
    • Associated with Sjögren's syndrome, subacute cutaneous lupus, inherited C′ deficiencies, ANA-negative lupus, lupus in the elderly, neonatal lupus,
    • congenital heart block.
    • Can cause nephritis
  • Anti La (SS-B)
    • Always assoc with anti-Ro Sjogrens. Low nephritis risk.
  • Anti Histone Ab
    • More commonly seen with Drug Induced than spont Lupus.
  • Anti-erythrocyte/platelet/lymphocyte and neuronal Abs have the obvious associated manifestations.

17

A girl was born at term weighing 2.5kg. Her chromosome analysis is XX. She is noted to have retrograde micrognathia and a U shaped cleft.
Her picture is shown below.
Which description best summarises these features:

A. Sequence
B. Association
C. Syndrome
D. Deformation
E. Disruption

Answer A. Sequence

Pierre-Robin Sequence
The pattern of multiple anomalies that occurs when a single primary defect in early morphogenesis produces multiple abnormalities through a cascading process of secondary and tertiary errors in morphogenesis is called a sequence.
The Robin malformation sequence is a pattern of multiple anomalies produced by mandibular hypoplasia. Because the tongue is relatively large for the oral cavity, it drops back (glossoptosis), blocks closure of the posterior palatal shelves, and causes a U-shaped cleft palate. There are numerous causes of mandibular hypoplasia, all of which result in characteristic features of Robin sequence.

18

What is the major objective of a phase I clinical trial?

A. Adverse events in humans.
B. Efficacy of a drug for a given indication.
C. Safety of a drug prior to use in humans.
D. Likely risk ratio.
E. Pharmacological and metabolic effects in humans.
 

Answer E. Pharmacologic and metabolic effects in humans

Clinical trials: ThEG

Phase0 – can you use this on a dog?!
Phase1 – Toxicity (healthy humans)
Phase2 – Efficacy (diseased humans)
Phase3 – efficacy compared to Gold standard
Phase4 – post-marketting surveillance

19

A 2-year old with a malignancy has samples sent for analysis by fluorescence in situ hybridization (FISH).

This is an example of which cytogenetic finding?
A. Amplification
B. High level aneusomy
C. Hyperdiploidy
D. Hypodiploidy
E. Tetrasomy

Answer A. Amplification

FISH "lights up" a target sequence which would usually result in two "lights" - one on each chromosome. More lights would indicate amplification of that sequence.

Aneusomy is in a tumour when cells have a different number of chromosomes. There would need to be more than one cell pictured for this to be the answer.

Hyperdipoid is to have more than the diploid number of chromosomes, and hypodiploid has less than the diploid number of chromosomes.

Tetrasomy is four copies instead of two of a particular chromosome.

20

Patients with Cystic Fibrosis who have pancreatic insufficiency require supplementation of exogenous pancreatic enzymes. Supplementation works best when the dose is adjusted depending on the content of meals.
Which of the following would require the highest dose of pancreatic enzyme supplement?
A. A banana
B. A bowl of canned vegetable soup
C. A fillet of grilled fish
D. A can of cola
E. A 100g packet of roasted peanuts
 

Answer E. A 100g packet of roasted peanuts.

Pancreatic enzymes are required to avoid fat malabsorption due to pancreatic insufficiency. The higher the fat content of the meal, the higher the dose of pancreatic enzyme. Multiple porcine preparations exist with varying concentrations of lipase, protease and amylase.

Peanuts has the highest fat content of all the answers and will therefore require the highest dose of pancreatic enzyme.

Excessive doses can cause fibrosing colonopathy. Prolonged contact of beads on the oral mucosa can cause ulceration.

21

PTH is required for calcium metabolism by acting on intestines, bone and kidneys. What decreases in response to PTH?
A. Bone resorption
B. Intestinal absorption
C. Renal PO4 reabsorption
D. Renal Ca reabsorption
E. Vitamin D activation 

Answer C. Renal PO4 reabsorption

PTH = calcium in, phosphate out

PTH increases serum calcium in three ways. 1. Increased intestinal absorption; 2. increased bone resorption; and 3. enhanced distal tubular reabsorption

Decreased serum calcium levels stimulate increased PTH secretion. PTH enhances renal production 1,25(OH)2D3 which induces synthesis of calcium binding protein in the intestinal mucosa for increased calcium absorption.

PTH also directly causes bone resorption (and requires 1,25(OH)2D3 for this process).

PTH stimulates calcium reabsorption in the distal tubules and PO4 excretion. Phosphate homeostasis regulated by the kidneys. Almost 100% absorption so serum level is dependent on renal excretion.

22

If a pregnant woman acquires primary varicella it can affect her baby with limb hypoplasia, skin scarring, and eye abnormalities. At what gestation is a fetus at greatest risk of this syndrome if exposed to varicella infection?
A. < 7 weeks
B. 8-13 weeks
C. 14-20 weeks
D. 21-28 weeks
E. 1 week prior to delivery 

Answer C. 14-20 weeks

Congenital Varicella Syndrome

  • When pregnant women contract varicella early in pregnancy as many as 25% of the foetuses may become infected.
  • Clinically apparent disease in the infant is, however, uncommon
  • The congenital varicella syndrome occurs in approximately 0.4% of infants born to women who have varicella during pregnancy before 13wk of gestation and approximately 2% of infants born to women with varicella between 13 and 20wk of gestation.
  • Congenital varicella syndrome is characterized by cicatricial skin scarring in a zoster-like distribution, limb hypoplasia, and neurologic (e.g., microcephaly, cortical atrophy, seizures, and mental retardation), eye (e.g., chorioretinitis, microphthalmia, and cataracts), renal (e.g., hydroureter and hydronephrosis) and autonomic nervous system abnormalities (neurogenic bladder, swallowing dysfunction, and aspiration pneumonia).
  • The characteristic cutaneous lesion has been called a cicatrix, a zigzag scarring, in a dermatomal distribution, often associated with atrophy of the affected limb
  • Virus cannot be cultured from the affected newborn, but viral DNA may be detected in tissue samples by polymerase chain reaction
  • Varicella immune globulin has often been administered to the susceptible mother exposed to varicella; not known if this actually helps
  • Acyclovir is a class B drug for pregnancy and should be considered only when the benefit to the mother outweighs the potential risk to the foetus

 

Neonatal Varicella

  • Risk for the baby is greatest if the mother contracts VZV close to delivery (especially 5 days prior to two days post)
  • The foetus contracts it through the placenta due to maternal viraemia (this may be before mum even has a rash)
  • Baby usually develops the rash toward the end of the first week → start of the second week of life
  • This is dangerous because the baby receives a large ‘dose’ of virus without corresponding antibodies, as mum is yet to develop them by delivery
    • This is why if it’s more than 5 days between transmission and delivery, the risk is ↓ (mum will have had the chance to pass on antibodies)
  • Guidelines for VariZIG (human varicella zoster immune globulin)
    • Newborns whose mothers demonstrate varicella 5 days before to 2 days after delivery should receive 1 vial of VariZIG as soon as possible.
    • All premature infants born 1wk) should receive VariZIG
  • If VariZIG not available- give IVIG (not as effective but better than nothing)
  • Treat with acyclovir IV when lesions develop
  • Neonatal varicella can also follow a postpartum exposure of an infant delivered to a mother who was susceptible to VZV, although the frequency of complications declines rapidly in the weeks after birth
  • Infants with community-acquired varicella who experience severe varicella should also get IV acyclovir

23

Capsule endoscopy is becoming more frequently used. Which of the following is the best indication for the use of capsule endoscopy?

A. Familial polyposis coli
B. Obscure GI bleeding
C. Recurrent intestinal obstruction
D. Swallowing problems
E. Ulcerative Colitis
 

Answer B. Obscure GI bleeding

Indications for capsule endoscopy include diagnosis of site of obscure GI bleeding, suspected crohns and small bowel tumours.

24

A 2 year old boy with autism does not respond to his name despite you repeatedly calling it in your clinic room. This is most likely due to a deficit in:
A  Auditory processing
B  Receptive language
C  Hearing
D  Social relatedness
E  Cognition 

Answer D. Social relatedness
 

  • Symptoms of autism spectrum disorder (ASD) most commonly are recognized in the second year of life, but may be present earlier or manifest later when social demands exceed limited capacities.
  • Impaired social communication and interaction may manifest as lack of social and emotional reciprocity; lack of seeking to share enjoyment, interests, or achievement; impaired use of nonverbal behaviors to regulate social interaction (eg, eye gaze, facial expression, gestures); and failure to develop age-appropriate peer relationships.
  • Restricted and repetitive behaviors, activities, and interests may include stereotyped and repetitive motor mannerisms, inflexible adherence to nonfunctional routines or rituals, preoccupation with stereotyped or restricted patterns of interest, and hyper- or hyposensitivity to sensory input.
  • ASD may or may not be associated with intellectual and/or language impairment, and other genetic, medical, or environmental factors.

25

In meiosis, pairing of homologous chromosomes happens during which of the following phases?
A. Anaphase 1
B. Interphase
C. Metaphase 2
D. Prophase 1
E. Telophase 1

Answer A. Prophase I

Prophase = pairing
Metaphase = middle
Anaphase = apart
Torn in two - telophase

 

Meiosis begins in the female oocyte during fetal life and is completed years to decades later. In males, it begins in a particular spermatogonial cell sometime between adolescence and adult life and is completed in a few days. Meiosis is preceded by DNA replication so that at the outset each of the 46 chromosomes consists of 2 chromatids. In meiosis, a diploid cell (2n = 46 chromosomes) divides to form haploid cells (n = 23 chromosomes). Meiosis consists of 2 major rounds of cell division. In meiosis I, each of the homologous chromosomes pair precisely so that genetic recombination, involving exchange between 2 DNA strands (crossing over), can occur. This results in a reshuffling of the genetic information on the recombined chromosomes and allows further genetic diversity. Each daughter cell then receives 1 of each of the 23 homologous chromosomes. In oogenesis, 1 of the daughter cells receives most of the cytoplasm and becomes the egg, whereas the other smaller cell becomes the 1st polar body. Meiosis II is similar to a mitotic division but without a preceding round of DNA duplication (replication). Each of the 23 chromosomes divides longitudinally, and the homologous chromatids migrate to opposite poles of the cell. This produces 4 spermatogonia in males, or an egg cell and a 2nd polar body in females, each with a haploid (n = 23) set of chromosomes. Consequently, meiosis fulfills 2 crucial roles: It reduces the chromosome number from diploid (46) to haploid (23) so that upon fertilization a diploid number is restored, and it allows genetic recombination.

26

A 2yr-old girl with developmental delay presents to the emergency department following a fall off a trampoline. She undergoes a CT brain which is shown below.
This imaging is most consistent with which of the following?

A. Subdural haemorrhage
B. Extradural haemorrhage
C. Subarachnoid haemorrhage
D. Intracerebral haemorrhage
E. Intraventricular haemorrhage

Answer A. Subdural haemorrhage

Subdural collections appear as crescent shaped, often extending widely across the convexity of a cerebral hemisphere.

Extradural haemorrhage is a convex lenticular lesion.
Subarachnoid haemorrhage is a more generalised bleeding pattern which will often follow the contours of the brain.

27

At what age does foetal haemoglobin make up less than 2% of total haemoglobin?
A. 36 weeks gestation
B. 40 weeks gestation
C. 3 months
D. 6 months
E. 12 months
 

Answer D. 6 months

The red cells of the newborn contain about 80 percent HbF and 20 percent HbA. By the time individuals are older than six months, HbF constitutes less than 1 percent of the total hemoglobin, and is distributed unevenly among red cells.

28

A 3 week old baby of Somali parents presents to the emergency department with convulsions. Investigations include:

  • Serum calcium 1.60 mmol/L [2.15-2.60] 
  • 
Phosphate
 2.1 mmol/L [1.1-1.8]

  • 25-hydroxyvitamin D (25 OHD) 40 nmol/L [30-150]

  • Parathyroid hormone (PTH) 1.0 pmol/L [1.2-6.4]
  • Magnesium
 0.5 mmol/L [0.7-1.1] 
  • Alkaline phosphatase (ALP) 300 U/L [100-350]


Which of the following is the most likely diagnosis?

A. Congenital hypomagnesaemia.
B. Congenital hypoparathyroidism.
C. Hypophosphataemia.
D. Pseudohypoparathyroidism.
E. Vitamin D deficiency. 

29

A 10 year old girl presents with persistently elevated blood pressure, symptoms of flushing, palpitations and headache. Phaeochromocytoma is suspected.
What would be the best investigation to aid you in your diagnosis?

A. PET scan
B. Abdominal MRI scan
C. MIBG scintigraphy
D. Plasma free metanephrines
E. Urinary spot catecholamines 

Answer D. Plasma free metanephrines

The diagnosis in the pediatric age group is best confirmed by measurement of 24-hour fractionated urinary metanephrines and catecholamines followed by radiographic localization of the tumor. In young children in whom an accurate 24-hour urine collection is not possible, measurement of plasma fractionated metanephrines is a reasonable alternative initial test.

Phaeochromocytoma -catacholamine secreting tumour of neuroectodermal tissue.

Present with:

  • Hypertension (50% sustained, 50% intermittent), weightloss, headaches, chest pain, attacks of sweating/flushing/tachycardia/palpitations, polyuria/nocturia/glycosuria with IGT. Also behavioural changes
  • Paroxysms usually last 15-45 mins

30

Ondansetron is a drug used in the treatment of nausea and vomiting. It exerts its actions through its interactions with which receptor?

A. Serotonin
B. Histamine
C. Acetylcholine
D. Dopamine
E. Substance P 

A. Serotonin

MOA of ondansetron and granisetron: central & peripheral 5HT3 (serotonin) receptor blockade.

Ondansetron is a potent, highly selective 5HT3-receptor antagonist. Its precise mode of action in the control of nausea and vomiting is not known. Chemotherapeutic agents and radiotherapy may cause release of 5HT in the small intestine, initiating a vomiting reflex by activating vagal afferents via 5HT3-receptors. Ondansetron blocks the initiation of this reflex. Activation of vagal afferents may also cause a release of 5HT in the area postrema, located on the floor of the fourth ventricle, and this may also promote emesis through a central mechanism.

Nausea and vomiting
Vomiting is co-ordinated in the medulla in the nucleus tractus solitaries

Main inputs
1. ‘Chemoreceptor trigger zone’ - located in the area postrema in the floor of the fourth ventricle, sensitive to humoral factors including drugs/toxins.

2. Vagal afferents from the GIT
Five neurotransmitter receptors involved

  • 5-HT3 - Serotonin
  • M1 – muscarinic
  • D2 – dopamine
  • H1 – histamine
  • Neurokinin 1 (NK1) – substance P

Sites

  • Area postrema – M1, D2, 5-HT3, NK1
  • Vestibular – H1
  • Vagal – 5-HT3
  • GIT – Dopamine receptors

Anti-emetics

Serotonin receptor antagonists e.g. ondansetron

  • H1 receptor antagonists e.g. cyclizine
  • Dopamine receptor antagonists e.g. metoclopramide, domperidone Increase peristalsis in upper gut
  • Anti-cholinergics – Hyoscine
  • Somatastatin analogues - octreotide

31

Abnormalities of which normal homeostatic control mechanisms are involved in the pathogenesis of recurrent non-diarrhoeal haemolytic uraemic syndrome?

A. Antibody-mediated immunity
B. Cell-mediated immunity
C. Complement mediated immunity
D. Coagulation system
E. Apoptosis 

Answer C. Complement mediated immunity

  • Hemolytic uremic syndrome (HUS) is defined by the concurrent characteristic triad of HUS: microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury.
  • The most common cause of HUS is due to Shiga toxin-producing Escherichia coli (STEC). Complement-mediated HUS accounts for most of the non-STEC HUS. (UTD)
  • Rare
  • The complement proteins associated with complement-mediated HUS are components of the alternative complement pathway.

32

Metformin is used to treat type 2 Diabetes Mellitus. With what mechanism does it exert its therapeutic action?

A. Decreased appetite and hence oral intake via serotonin and noradrenaline.

B. Gastrointestinal uptake of glucose precursors via pancreatic lipase.

C. Increased insulin production via an ATP dependant mechanism.

D. Increased insulin sensitivity via peroxisome activated receptor gamma (PPARγ) nuclear receptor.

E. Suppressing hepatic gluconeogenesis and increased peripheral glucose utilisation.

Answer E. Suppressing hepatic gluconeogenesis and increased peripheral glucose utilisation.

MOA: Decreases hepatic glucose production, decreasing intestinal absorption of glucose and improves insulin sensitivity (increases peripheral glucose uptake and utilization)

33

A 15 yo female presents with headaches and decreased visual acuity. She has had 12 months without her periods. On examination, she has papilloedema.
CT- ?suprasellar mass with post contrast changes What is the most likely diagnosis?

A. AVM
B. Craniopharyngioma
C. Pituitary adenoma
D. Arachnoid cyst
E. Medulloblastoma

Answer B. Craniopharyngioma


Craniopharyngiomas

  • SOLID/CYSTIC tumours that arise from remnants of Rathke’s pouch along a line from the nasopharynx to the diencephalon
  • Rare – 5-10% of brain tumours in children, M=F, peak age 5-14 years
  • Epithelial tumours that usually arise in the pituitary stalk in the suprasellar region, adjacent to the optic chiasm (small percentage arise within the sella)
  • Histologically benign BUT frequently shorten life-span and should be considered to be low-grade malignancies
  • Most contain both solid and cystic components (cysts contain turbid fluid with cholesterol crystals)
  • Vary from small, solid, well circumscribed masses to huge multilocular cysts that invade the sella turcica and displace neighbouring structures (3rd ventricle, base of brain, etc)

Presentation:

  • Slow-growing so symptoms are often present for a year or more before diagnosis is established
  • Visual symptoms: common. Due to direct pressure on the chiasm but specific deficit depends on growth pattern of the tumour
  • Endocrine effects: direct damage to/compression of normal structures can lead to a range of endocrine abnormalities. In order of frequency:
  • GH (75%) > LH/FSH (40%) > TSH (25%) > ACTH (25%)
  • DI is frequent when the pituitary stalk is involved
  • Growth failure (lack of GH/TSH) is the most common presentation in children; in adults, sexual dysfunction is the most common complaint in men while amenorrhoea is present in most women
  • Severe headache in 50% (mass effect of tumour/obstructive hydrocephalus/meningeal irritation from escaped cystic fluid)
  • Depression is also common - ?due to extension into frontal lobes

Diagnosis:

  • MRI/CT
  • Calcification in the suprasellar region is seen in 60-80% of patients with CP; cysts are present in 75%
  • Hence a cystic, calcified parasellar lesion is very likely to be a craniopharyngioma
  • Differential: other parasellar tumours
  • Pituitary macroadenoma, meningioma, optic gliomas, germinomas, teratomas, lymphoma, infiltrative disorders (sarcoid, histiocytosis)

Treatment:

  • Endocrine testing to look for hypopituitarism pre-op (so it can be corrected)
  • Ophthalmology as pre-op baseline
  • Surgery (aggressive, vs conservative + RTx is controversial)
  • 10 yr survival ~90%

Complications:

  • Panhypopituitarism (due to tumour/treatment) in the majority – hypogonadism, hypothyroidism, adrenal insufficiency, GH deficiency. Hypothalamic dysfunction can create disorders of temperature regulation, sleep, obesity and DI
  • Neurologic – neuropsychiatric, behavioural and intellectual impairments common
  • Visual deficits – present in the majority even pre-treatment
  • Secondary malignancies – malignant glial tumours

34

What inheritance pattern is represented below?

A. Autosomal recessive or autosomal dominant
B. Mitochondrial or X-linked recessive
C. X-linked recessive or autosomal recessive
D. X-linked dominant or X-linked recessive
E. Y-dominant or X-linked recessive 

ANSWER C. X-linked recessive or autosomal recessive

  • AR: Yes. Unaffected parents, affected children. (Though statistically you would expect ¼ offspring to be affected – bad luck in this case).
  • AD: Maybe – only if you qualify it as AD with incomplete penetrance (hence parents not affected) OR anticipation (OR parental germline mosaic)
  • Mitoch: Maybe – all offspring of affected mother usually affected but can be spared via heteroplasmy. Would usually expect mother to be affected though. Would be bad luck for her not to have it, and 3 of her 4 kids to be affected.
  • XLR: Yes. Unaffected mother and daughter, all sons affected.
  • XLD: No. Mother would be affected.
  • YD: No. Father would be affected.

Mitochondrial Inheritance

  • When the defective gene is encoded in the mitochondrial genome
  • Mitochondria = organelles where aerobic metabolism occurs
  • Mitochondria contain their own circular 16,000 basepair genome, DNA and RNA polymerases, and protein translation apparatus (ribosomes, tRNA)
  • Many mitochondrial proteins are encoded by mitochondrial DNA (BUT some mitochondrial proteins are encoded by the nuclear genome and inherited in a mendelian fashion)
  • They are inherited exclusively from the cytoplasm of the oocyte during the formation of the zygote and are therefore exclusively maternal in origin (the sperm contributes only its nucleus)
  • Most children of an affected female are usually affected, but to varying degrees
  • Children of an affected male are NEVER affected
  • Examples include MERRF (myoclonic epilepsy with ragged red fibres), MELAS (mitochondrial myopathy/encephalopathy/lactic acidosis/stroke-like episodes) – both are mutations in the mitochondrial tRNA molecule
  • In mitochondrial inheritance, the disease can only be inherited from the mother, and usually ALL of an affected mother’s children are affected
  • However, sometimes children can escape inheriting a mitochondrial disorder or can be affected to varying degrees, depending on how the mutation is distributed within the population of mitochondria inherited from the mother – this is known as heteroplasmy
  • Heteroplasmy is used to describe the situation where a cell or tissue contains a mixture of mitochondria - both mutant and wild-type. The term homoplasmy describes the situation whereby all the mitochondria have the same genome, either wild-type or mutant
  • Symptoms of severe heteroplasmic mitochondrial disorders frequently do not appear until adulthood because many cell divisions and a lot of time is required for a cell to receive enough mitochondria containing the mutant alleles to cause symptoms. An example of this phenomenon is Leber optic atrophy. Individuals with this condition often do not experience vision difficulties until they have reached adulthood. In MELAS, heteroplasmy explains the variation in severity of the disease among siblings.
  • Pedigrees will show both male and female affected but only the females pass the disorder on. The pedigree can look superficially like an XR pedigree but there is no male transmission through carrier daughters
  • Mitochondria are randomly distributed into daughter cells, thus by chance alone some cells may receive more or less of the mutant mitochondria. Those tissues that receive a larger amount of defective mitochondria will have a lower ATP production. If the tissue is one which requires a large amount of energy such as cell of the nervous system, muscles, kidneys, etc., the person with the mutant mitochondria will be affected. 

35

At age 18 months failure to develop which of the following skills is indicative of developmental delay?

A. Pretend play (cup of tea )
B. Following simple instructions
C. Separation anxiety from mother
D. Failure to use simple gestures (pointing, waving bye-bye)
E.

Paediatric Secrets – Play Activity and Child Development

  • 3m – midline hands
  • 6m – transfers
  • 7-9m – banging, mouthing
  • 12m – casting – including use of pointing from 10-12mths; follows simple 1 step commands from 10-12m
  • 18m – stacking, lids, switches – exploring; knows multiple 1 step commands
  • 24m – imitative play (eg play with doll)
  • 36m – imaginative play (eg pretend pillow is doll)
  • 48m – simple rule-based games
  • Signs of speech-language problems absolutely needing further evaluation (ie RED FLAGS)

36

Which antibody isotype is reduced in protein-losing enteropathy?

A. A


B. D


C. E

D. G

E. M

Answer D. G

Protein losing enteropathy

  • Children with protein losing enteropathy have severe protein loss through the gut resulting in low plasma protein levels (hypoalbuminemia).
  • Causes include hypertrophic gastritis (Ménétrier's disease), milk protein allergy, celiac disease, inflammatory bowel disease, giardiasis, intestinal lymphangiectasia, and right sided heart dysfunction (post-Fontan procedure)
  • Stool level of alpha-1 antitrypsin is an excellent screening test for protein losing enteropathy, as alpha-1 antitrypsin is a nondietary, serum protein synthesized in the liver. It is of similar size to albumin but is resistant to intestinal and proteolytic digestion distal to the stomach.
  • Hypoproteinemia will occur if the extent of net enteral protein loss is greater than the capacity of liver to synthesize particular proteins. Hepatic protein synthesis in patients with protein-losing gastroenteropathy is usually normal or only slightly increased. Thus, gastrointestinal protein loss will reduce the serum concentrations of proteins that have a slow catabolic rate, such as albumin and some immunoglobulins (IgA, IgG, and IgM). By contrast, there is little change in the serum concentrations of proteins with a rapid turnover rate, such as insulin and IgE.
  • By comparison to hypoalbuminaemia, the reductions of other serum proteins rarely cause clinical problems. The changes in clotting factors are not significant and there is not a propensity to recurrent infection due to the hypogammaglobulinemia. However, in patients with lymphatic obstruction and particularly congenital lymphangiectasia, loss of lymphocytes into the gut can produce significant lymphocytopenia with detectable alterations in cellular immunity.

37

QUESTION 40
What is the average weekly weight gain from birth to 3 months?

A. 75g
B. 100g
C. 150g
D. 200g
E. 250g 

Answer D. 200g

  • Term neonates may lose up to 10 percent of their birth weight in the first few days of life and typically regain their birth weight by 10 to 14 days
  • Newborns gain approximately 30 g/day until three months of age
  • Infants gain approximately 20 g/day between three and six months of age and approximately 10 g/day between 6 and 12 months
  • Infants double their birth weight by four months of age and triple their birth weight by one year
  • Children gain 2 kg/year between two years and puberty

38

A new antiepileptic drug is trialled. Results show that the rates of severe neutropenia in the treatment group were 8% compared to 3% in the placebo group. How many people need to be treated with the new antiepileptic drug for 1 person to develop severe neutropenia.

A. 3
B. 5
C. 8
D. 20
E. 24 

Answer D. 20

Risk difference: 8% - 3% = 5% (0.05)
NNT: 1 / 0.05 = 20

39

Sodium Valproate is a teratogenic drug if taken during pregnancy. What is the rate of congenital malformation?

A. 1%
B. 10%
C. 20%
D. 30%
E. 50% 

Answer A. 1%

Uptodate:
1 to 2% of fetuses exposed to valproate in utero develop neural tube-like defects.
(10-20 fold increased over general population)

40

Primary ciliary dyskinesia is a disease of cilia dysfunction. The primary manifestation is cough. Which of the following systems is the NEXT most likely to be affected in childhood?

A. Cardiac
B. Renal
C. Gastrointestinal
D. Otological
E. Genital 

Answer D. Otological

  • Primary ciliary dyskinesia (PCD, also called the immotile-cilia syndrome) is characterized by congenital impairment of mucociliary clearance (MCC). Clinical manifestations include chronic cough, chronic rhinitis, and chronic sinusitis. Otitis and otosalpingitis are common in childhood, as are nasal polyposis and agenesis of the frontal sinuses. The underlying cause is a defect of cilia in the airways, making them unable to beat (ciliary immotility), unable to beat normally (ciliary dyskinesia), or to be missing altogether (ciliary aplasia).
  • Autosomal recessive
  • M=F
  • Because the embryonic, nodal cilia are also defective, body asymmetry is randomized so that approximately 50 percent of the patients have situs inversus totalis. When situs inversus, chronic sinusitis, and bronchiectasis occur together, an individual is said to have Kartagener's syndrome, a subgroup of primary ciliary dyskinesia that has a prevalence of around one in 20,000 to 40,000 individuals. Bronchiectasis may develop in young persons, but is never present at birth; thus, no individual is born with a fully developed Kartagener's triad.

41

A 6 year old boy had otitis media and was treated with cefaclor. 2 weeks later he developed an urticarial rash and joint swelling. What type of reaction is this?

A. Anaphylactoid
B. Type 1 (Immediate hypersensitivity)
C. Type 2 (Cytotoxic antibody reaction)
D. Type 3 (Immune complex reaction)
E. Type 4 (Delayed type hypersensitivity) 

Answer D. Type 3 (Immune complex reaction)

Classic Cefaclor reaction (serum sickness-like reaction, in Type 3/immune complex hypersensitivity reaction)

 

42

What is the anatomical position of a cephalohaematoma?

A. Between the dura and arachnoid mater.
B. Between the dura and skull
C. Between the skull and periosteum.
D. Between the periosteum and aponeurosis.
E. Within the soft tissue. 

Answer C. Between the skull and the periosteum

SPADE: Skull < Periosteum < Aponeurosis (galea aponeurotica, hence ‘subgaleal’) < Dermis < Epidermis
Cephalhaematoma = Capped by the sutures
Subgaleal = spreads everywhere

Majority (90%) result from vacuum applied to the head at delivery (Ventouse assisted delivery). The vacuum assist ruptures the emissary veins (connections between dural sinus and scalp veins) leading to accumulation of blood under the aponeurosis of the scalp muscle and superficial to the periosteum[1]. Subgaleal hematoma has a high frequency of occurrence of associated head trauma (40%), such as intracranial hemorrhage or skull fracture. The occurrence of these features does not correlate significantly with the severity of subgaleal hemorrhage.

43

The arrow in the picture shows:
A. Basophil
B. Eosinphil
C. Lymphocyte
D. Neutrophil
E. Monocyte 

Answer B. Eosinophil

Bilobed nucleus with brick red stained granules (after staining with red dye called “eosin”).

44

Which of the following bacteria does not respond to treatment with flucloxacillin?

A. Enterococcus faecalis
B. Coagulase negative staph
C. Peptostreptococci
D. Streptococcus pneumonia
E. Viridans streptococci 

Answer A. Enterococcus faecalis

E. faecalis usually cause UTI, septicaemia or meningitis. G+ cocci, relatively resistant to killing effects of cell wall active agents incl. penicillin, ampicillin and vancomycin and are impermeable to amino glycosides (gentamicin, amikacin, tobramycin). Requires combination regimen of two agents. EITHER a cell wall active agent with a synergistically active aminoglycoside; OR ampicillin with ceftriaxone.

Coagulase negative staph is usually a nosocomial infection associated with foreign bodies. Gram positive cocci. Treatment of choice is vancomycin. Resistance to methicillin and semi synthetic penicillins in 80% of cases.

Peptostreptococci is a commensal gram positive anaerobic cocci which can cause pathogenesis in immunocomprised or in traumatic conditions. Can cause abscesses and necrotising soft tissue infections. Treatment choices include penicillins (penicillin G first choice), cephalosporins, vancomycin, clindamycin. Macrolides (erythromycin) and imidazoles (metronidazole) are variable and unreliable.

Streptococcus pneumoniae is a gram positive, alpha haemolytic, aero-tolerant anaerobic cocci. In children it causes meningitis, CAP, otitis media, conjunctivitis, bacteraemia and cellulitis. Pneumococcal vaccinations at 2, 4 and 6 months of age, plus additional if at risk group. Most strains in Australia are sensitive to penicillin and first line treatment is IV benpen, step down to PO amoxycillin (if mild, can use PO amoxycillin first line). If penicillin resistant, can use ceftriaxone or cefotaxime with step down to cefuroxime PO.

Viridans streptococci is usually commensal mouth organism. It can be either alpha or non haemolytic and is a gram positive cocci. It does not usually cause disease but can cause endocarditis particularly after dental trauma. Strep viridans are mostly susceptible to penicillin (gent can be used synergistically, but not essential). In the 15% of cases resistant to penicillin, gentamycin and vancomycin are used.

45

Type 1 Diabetes Mellitus is an auto-immune disorder involving β-cell destruction. By the time child is symptomatic with Type-1 DM, how many β-cells have been destroyed.

A. 20%.
B. 40%.
C. 60%.
D. 80%.
E. 100%.
 

Answer D. 80%

46

The gene defect in chronic granulomatous disease affects which protein?

A. Catalase
B. Myeloperoxidase
C. NADPH oxidase
D. Neutrophil elastase
E. Lactoferrin 

Answer C. NADPH oxidase

Chronic granulomatous disease (CGD) is a genetically heterogeneous condition characterized by recurrent life-threatening bacterial and fungal infections and granuloma formation.

CGD is caused by defects in the phagocyte NADPH oxidase (phox). These genetic defects result in the inability of phagocytes (neutrophils, monocytes, and macrophages) to destroy certain microbes.

Infections are generally caused by catalase-positive microorganisms (most bacterial and all fungal pathogens are catalase-positive). The frequent sites of infection are lung, skin, lymph nodes, and liver. The formation of granulomata is especially problematic in the gastrointestinal and genitourinary tracts. 

Up to Date

47

A 10 year old boy with known mitral valve regurgitation presents with increasing exercise intolerance, but no signs of heart failure. An echocardiogram shows a dilated left ventricle, decreased fractional shortening, and moderate to severe mitral regurgitation. What is the underlying cause of these findings?

A. Increased pulmonary vascular resistance
B. Decreased pulmonary vascular resistance
C. Increased cardiac volume overload
D. Ischaemic injury
E. Increased cardiac afterload

Answer C. Increased cardiac volume overload.
Mitral regurgitation (MR) burdens the left ventricle (LV) with an excessive volume load that leads to a series of compensatory myocardial and circulatory adjustments. These compensatory adjustments vary over the prolonged course of the disorder. In severe MR, the myocardium eventually fails, the ventricle decompensates, and the patient exhibits signs of heart failure. (UTD)

Fractional shortening is a measure of the ratio of the LV in diastole and systole. Normal is >26%. Decreasing fractional shortening indicates progression of disease.

48

Which muscle is innervated by Trochlear nerve (CN IV)?


A. Medial rectus
B. Lateral rectus
C. Superior oblique
D. Superior rectus
E. Inferior rectus

Answer C. Superior Oblique
LR6, SO4
Lateral rectus CN VI (Abducens), superior oblique CNIV (trochlear), all else by CNIII (Oculomotor).

49

Which of the following is the most important property of a screening test?

A. Specificity
B. Sensitivity
C. Positive Predictive Value
D. Negative Predictive Value
E. Likelihood ratio

Answer B. Sensitivity

50

What is the process behind epigenetics?

A. Deactivation of DNA
B. Expansion of triplet repeats
C. Methylation of mRNA
D. Reverse transcriptase
E. Molecular changes to DNA morphology?

??Answer A. Deactivation of DNA


A modification of a chromosome that does not alter the nucleotide base sequence, but alters the expression of a gene. Epigenetic changes may be stable in an individual, but may be reversed during gametogenesis or early development. DNA methylation and histone acetylation are common epigenetic changes. Epigenetic changes form the mechanistic basis of imprinting. (UTD)
Epigenetics can affect the expression of DNA by two main mechanisms: by modifying the DNA or by modifying the chromatin.

51

Which of the following structures does Vancomycin most closely resemble?

A. Clarithromycin
B. Clindamycin
C. Gentamicin
D. Ciprofloxacin
E. Teicoplanin
 

Answer E. Teicoplanin

Vancomycin and Teicoplanin are glycopeptide antibiotics.

52

A renal biopsy, performed 2 weeks post renal transplant, shows acute cellular rejection (pictured).

Which cell type mediates this immune process:
A. B Cell
B. Macrophage
C. NK Cell
D. Neutrophil
E. T Cell

Answer E. T Cell

Answer E. T Cell
Hyperacute rejection occurs immediately when the kidney is transplanted and is due to preformed antibodies against the donor HLA, ABO, or other antigens. Hyperacute rejection is rare. The only treatment is removal of the graft.

Acute cellular rejection needs to be identified and treated early. Diagnosis of acute rejection in the very young transplant recipient is often not straightforward. Because most small children receive adult-sized kidneys, an elevation in serum creatinine may be a late sign of rejection as a result of the large renal reserve compared with the body mass. Thus, significant allograft dysfunction may be present with little or no increase in the serum creatinine level. One of the earliest and most sensitive signs of rejection is the development of hypertension along with low-grade fever. In children, any increase in serum creatinine, especially if it is accompanied by hypertension, should be considered a symptom of acute rejection until proved otherwise. Late diagnosis and treatment of rejection are associated with higher incidence of resistant rejections and graft loss.

At the present time, renal allograft biopsy with conventional histologic examination remains the gold standard for diagnosing acute rejection among transplant patients with a deterioration in kidney function. The two principal histologic forms of acute rejection are:
Acute cellular renal allograft rejection, which is characterized by infiltration of the allograft by lymphocytes and other inflammatory cells.

Acute antibody mediated rejection, which requires morphologic evidence of acute tissue injury, circulating donor-specific allo-antibodies, and immunological evidence of antibody-mediated process (C4d+). It may not be associated with cellular infiltrates.
Chronic rejection is the leading cause of graft loss and primarily results from immune and nonimmune injuries such as hypertension, diabetes, and hyperlipidemia.

Children often have a gradual decline in their renal function and often have fixed proteinuria and hypertension. Despite initial excitement about the potential of MMF and sirolimus mitigating chronic graft injury, this has not translated readily into observable clinical benefits.

53

A Forrest Plot represents the results of 2 randomised control trials and 1 meta analysis comparing placebo and treatment with iron supplements in the reduction or resolution of breath holding episodes.

The best interpretation is:

A. A large clinical effect, that is not statistically significant
B. A large clinical effect, that is statistically significant
C. A small clinical effect, that is not statistically significant
D. A small clinical effect, that is statistically significant
E. No clinical effect.

Answer B. A large clinical effect, that is statistically significant
 

Forest Plots

  • A graphical display designed to illustrate the relative strength of treatment effects in multiple quantitative scientific studies addressing the same question (i.e. it looks at a few different studies that have been done to draw some conclusion)
  • It is a means of graphically representing a meta-analysis of the results of randomised controlled trials
  • Commonly presented with 2 columns. The left-hand column lists the names of the studies. The right-hand column is a plot of the measure of effect (odds ratio) for each of these studies (often represented by a square) incorporating confidence intervals represented by horizontal lines.
  • The area of each square is proportional to the study’s weight in the meta-analysis
  • The overall meta-analysed measure of effect is often represented on the plot as a vertical line. This meta analysed measure of effect is commonly plotted as a diamond, the lateral points of which indicate confidence intervals for this estimate
  • A vertical line representing no effect is also plotted. If the confidence intervals for individual studies overlap with this line, it demonstrates that at the given level of confidence their effect sizes do not differ from no effect for the individual study
  • The same applies for the meta-analysed measure of effect: if the points of the diamond overlap the line of no effect the overall meta-analysed result cannot be said to differ from no effect at the given level of confidence

Wiki

54

A couple have a child with autism. What is the chance of their next child having an autism spectrum disorder?

A. 2%
B. 5%
C. 10%
D. 20%
E. 30% 

Answer B. 5%

UTD - 2-8%

From article on the FRACP rescources site http://www.rch.org.au/emplibrary/fracp_resources/autismBMJreview.pdf
The number of children diagnosed as having autistc spectrum disorders is increasing for various reasons
A diagnosis of autism can be reliably made at between 2-3 years of age
In most people with autism, genetic factors play a key role
Twin studies have shown that in monozygotic twins the change of concordance for autism is 60%, with a greater concordance for some social impairments, compared with a much lower rate in dizygotic twins
The rate of autistic spectrum disorders in singleton siblings is 2-6%, a marked increase above population rates

55

Which cardiac lesion is most common in rheumatic heart disease

A. Aortic stenosis
B. Mitral stenosis
C. Aortic regurgitation
D. Mitral regurgitation
E. Tricuspid regurgitation

Answer D. Mitral regurgitation

Mitral regurgitation is the most common early valvular manifestation and may be accompanied by aortic regurgitation; isolated aortic regurgitation is less common. Mitral regurgitation is often caused by mitral valve prolapse. Mitral valve prolapse in ARF involves predominantly the anterior leaflet with minimal leaflet redundancy, in contrast to myxomatous disease which more commonly involves the posterior leaflet and is associated with prominent leaflet redundancy. Leaflet prolapse appears to be due to annular dilation and chordal elongation. Aortic or mitral stenosis is unusual at presentation; these are typically late manifestations due to scarring and calcification of damaged valves.
Up to Date

56

Herediatary spherocytosis causes haemolysis.
What is the mechanism of this disease?

A. Cytoskeleton
B. Membrance ion channel
C. Haemoglobin
D. Surface antigen
E. Glycoprotein

Answer A. Cytoskeleton

Hereditary spherocytosis (HS) is a result of alterations in genes encoding for proteins which tie the red blood cell (RBC) inner membrane skeleton to its outer lipid bilayer.

Spectrin-deficient RBCs have decreased membrane mechanical stability, with progressive loss of the lipid bilayer by microvesiculation. This loss of surface area without loss of volume imposes the spherocytic shape on affected red cells.

Repeated passages through the splenic cords (splenic conditioning) promote further membrane lipid loss, leading to a progressively more spheroid red cell, preventing its passage through the narrow fenestrations of the splenic cords, and ultimately resulting in red cell destruction in that organ.

The central importance of the spleen is clearly seen following splenectomy, which virtually eliminates hemolysis and anemia in moderately severe cases, and eliminates the need for transfusion in severe cases.
 

57

At what age does a child understand the concept of death and accept its irreversible consequence. 

A.  2 years
B.  5 years
C.  8 years
D.  12 years
E.  16 years

Answer C. 8 years

Summarized From UTD

Children’s Understanding of Death at Different Ages

0-2 years

No understanding. Become stressed by the distress of adults around them.

3-5 years

Children of this age do not yet have an understanding of the irreversibility of death, and so they may also offer solutions to death, and expect the person to be “all better.” They may also attribute the grief and distress of other adults to their own behavior and need frequent reminders that they are not the cause of everyone’s upset feelings.
Egocentrism, associative logic and magical thinking predominates at this age.

6-12 years

Between the ages of 6 and 12 years, children are often immersed in acquiring academic, physical, and social skills, including mastering cause and effect. In addition, they are usually invested in notions of fairness, and are sensitive to things that set them apart from their peers. By the age of seven, children usually understand that death is permanent. However, they may demonstrate a preoccupation with factual, medical, or physical aspects of death and dying, which may be difficult topics for adults to discuss. The uncertainty about time that is inherent in terminal illness may be particularly hard for school-age children to grasp, especially at the younger ages in this group.

13-18 years

By 13 years, adolescents are forming their own identities and gaining a sense of comfort separate from their parents. They have the capacity for abstract thinking, although their brains do not fully mature until into their twenties. Adolescents understand that death is final, irreversible, and universal, and may think actively about existential and spiritual issues. They may vacillate between abstract ideas about their parent’s death and being preoccupied with very specific and self-centered ways in which it affects their life. They are also likely to project forward into the future and worry about their life progressing without their parent, anticipating sadness about milestones that their parent will not be there to witness.

58

A 2 yr old girl presented to ED with GCS of 15 with right superficial parietal haematoma. She is not co- operative for CT scan and requires sedation. Which sedation is contraindicated because of long half life?

A. IV Ketamine
B. IV propofol
C. Oral Midazolam
D. Oral Chloral Hydrate
E. Inhalant Seroflourane

Answer C. Oral Midazolam

Ketamine

  • onset within 30 seconds
  • Recovery within 1-2 hours
     

Propofol

  • onset within 30 seconds
  • duration 3-10 minutes

Oral Midazolam

  • onset 10-20 minutes
  • duration: doesnt say for oral dose, but states that full recovery may take more than 24 hrs

Oral Chloral Hydrate

  • onset 10-20 mins
  • duration 4-8 hrs

Inhalant Sevoflourane - inhaled anaesthetic agent often given with NO

  • onset within 2 minutes
  • duration is variable and depends on how long it is used for: if

59

Protein glycosylation occurs in:
A. Cytosol
B. Golgi
 

Answer B. Golgi

Occurs in the endoplasmic reticulum and golgi apparatus.

60

Which of the following components of human breast milk increases in concentration during the first month?

A. Immunoglobulin G
B. Lactalbumin
C. Lactoferrin
D. Lactose
E. Secretory IgA

Answer D. Lactose

  • Human milk does contain a little IgG and decreases from 43mg/dL in colostrum to 4 mg/dL in mature milk.
  • Lactalbumin is a general term describing the mixture of whey proteins found in breastmilk, chiefly alpha-lactalbumin and lactoferrin. Alpha lactalbumin decreases.
  • Lactoferrin also decreases from 5 - 7 g/L in colostrum to 1 -3 g/L in mature milk.
  • sIgA is high in colstrum and declines rapidly to nothing by day 14.
  • Lactose increases from 20g/L day 1 to 35 g/L day 28.

References: Breastfeeding a Guide for the Medical Profession by R Lawrence
Textbook of Human Lactation by T Hale and P Hartmann.
 

61

The parents of one of your patients are concerned that their pharmacy has dispensed a generic brand of their son’s usual medication. You read the profiles of the two drugs and deduce that they are bioequivalent.
This means that the two drugs must have:

A. Their respective AUC’s within 80% to 125% of each other
B. The AUC and peak concentration (Cmax) within 80% to 125% of each other
C. The AUC and time to peak concentration (Tmax) within 80% to 125% of each other
D. The Cmax within 80% to 125% of each other
E. The Tmax within 80% to 125% of each other

Answer B. The AUC and peak concentration (Cmax) within 80% to 125% of each other

As per dr wikipedia the Aus TGA defines bioequivalence as both the AUC and the peak concentration (Cmax) being within 0.8-1.25

62

What is the incidence of Coeliac’s Disease in the Western population?
A. 0.02%
B. 0.1%
C. 1%
D. 5%
E. 10%
 

Answer C. 1% 

63

In Type I DM, polyuria occurs due to osmotic diuresis. In which part of the kidney is water being prevented from being reabsorbed?

A. Glomerulus
B. Proximal convoluted tubule
C. Ascending loop of Henle
D. Distal convoluted tubule
E. Collecting duct