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Paediatrics > NZ Gastro > Flashcards

NZ Gastro Flashcards

1
Q

Pathophysiology of IBD

A

Multifactorial disease:

  1. Genetics: approx 200 susceptibility genes identified
    - Identical twins: risk 30-35%
  2. Environmental factors:
    - Smoking (protective for UC, increased risk for CD)
    - Appendicectomy (reduced risk of developing UC)
    - Breast feeding - conflicting evidence
    - NSAID use and infection - increases risk
  3. Dysbiosis:
    - Overactive immune response to normal gut flora
    - Putative infectious agents: TB, listeria, shigella, yersinia, Bacteroides vulgatus, measles, E. coli subtypes
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2
Q

Incidence of IBD

A

Prevalence: 1 in 400 in general population with 20-25% in childhood

Current trend: earlier childhood presentation, CD more common in paediatric population

UC: M=F, CD: M>F

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3
Q

Early onset IBD (<5yo)

A

Need to rule out:
Immunodeficiency
- IL10 deficiency
- Chronic granulomatous disease

Ix:

  • Neutrophil function
  • Lymphocyte subset
  • Immunoglobulin level
  • Genetic panel for monogenic causes
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4
Q

Growth failure in IBD

A

Weight loss
27% Wt <3rd centile
13% Ht <3rd centile
Delayed puberty

Secondary to:

  1. Decreased oral intake (anorexia, pain, increased stooling)
  2. Chronic inflammatory state (catabolic)
  3. Malabsorption
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5
Q

Long term height outcomes in IBD

A

Mean 2.4cm deficit in adulthood

19% >8cm below expected from mid-parental height
Ht Z-score inversely proportional to delay in diagnosis

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6
Q

IBD-related arthropathy

A
  1. Peripheral arthropathy:
    - Type 1: pauci-articular, large joints, asymmetrical, MIRRORS disease activity, HLA-B27, HLAB35 and HLA-DR related
    - Type 2: polyarticular, small joints, INDEPENDENT of disease activity, may be associated with uveitis
  2. Axial arthropathy:
    - 5-10%, ankylosing spondylitis or sacroiliac joint arthritis, independent of gut disease activity
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7
Q

Faecal calprotectin

A

Neutrophil derived inflammatory marker

  • 24kDa dimer of calcium binding proteins - present in cytoplasm of neutrophils
  • Not degraded by intestinal enzymes or bacteria

Highly sensitive marker for inflammation, but nonspecific

Falsely elevated with NSAID use

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8
Q

IBD work up

A
  • Inflammatory markers (ESR/CRP)
  • FBC: thrombophilia, anaemia
  • Albumin
  • Faecal calprotectin
  • TMPT genotype
  • Measles and varicella serology
  • Quantiferon Gold
  • PORTO Criteria:
  • -> Upper GI endoscopy, ileocolonoscopy, small bowel MRI
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9
Q

UC Histopathology

A

Loss of normal vascularity, erythema, ulceration, contact bleeding, friability, pseudopolyps (secondary to chronic inflammation), increased inflammatory cells in lamina propria, crypt abscesses, crypt irregularity

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10
Q

CD Histopathology

A

Non-necrotising granulomas, transmural inflammation, fissuring

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11
Q

Crohn’s: Induction therapy

A
  1. Enteral nutrition
    - Enteral nutrition as effective as steroids in inducing remission (70% of cases)
    - MOA: modulating gut microbiota in 8 weeks, prebiotic properties
    - Benefits: improves growth delay and BMD, enables catch up vaccinations
    - Progress: in responsive pts, will improve by ~14 days –> slow reduction in inflammatory process and weight gain
    - Options: elemental vs polymeric
    - Duration: exclusive enteral nutrition for 8 weeks (yuck)
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12
Q

Exclusive Enteral Nutrition in CD: Cochrane Review

A
  1. EEN remission rates from 20-84.2%
  2. Protein and fat source - no difference in outcome
  3. No significant difference between polymeric vs elemental
  4. Site of disease: not enough evidence to favour one particular site, may not respond as well if extensive colonic disease
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13
Q

Exclusive Enteral Nutrition in CD: In Practice

A
  1. 110 children treated so far with 8 weeks EEN
  2. Requires intensive dietetic support
  3. Clinical remission in 79.2%
  4. No clear phenotypic variation
  5. Significant improvement in ESR and CRP
  6. Mean weight gain of 7kg
  7. Wt improvement maintained to 6mth
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14
Q

EEN feed options

A

Elemental

  • Amino acid-based feeds
  • High osmolality
  • Poor palatability
  • 1kCal/mL (large volumes need to be consumed)

Polymeric

  • Whole protein
  • Less expensive
  • Improved palatibility
  • 1-1.5kCal/mL
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15
Q

TMPT deficiency and Azathioprine

A

1: 300 have TMPT deficiency (homozygotes)
- Shunts 6-MP to form more 6-TGN (thioguanine nucleotide)
- Significant bone marrow suppression

Homozygotes: consider alternative immunomodulator or significant dose adjustment

Heterozygotes: requires dose adjustment and close monitoring of FBC and 6-TGN levels

Need to measure TPMT level and ascertain genotype at time of IBD diagnosis
- Lag period of 3 months before Aza becomes effective –> can commence Aza therapy whilst awaiting TMPT genotype

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16
Q

Side effects of azathioprine

A
  1. Myelosuppression - dose dependent
  2. Pancreatitis
  3. Infection risk: VZV, EBV
  4. Hepatitis
  5. Malignancy: 4-fold risk of lymphoma
  6. Susceptibility to sun-related skin damage
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17
Q

Therapeutic monitoring of azathioprine

A
  1. Safety: FBC, LFTs, amylase, 6TG, 6MMP

2. Efficacy: 6TG

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18
Q

Predicting need for azathioprine therapy in IBD

A

Following induction of remission, majority require immunosuppression to maintain remission

  • 75% of CD and 50% of UC by 2yrs
  • 85% CD by 5yo

CD: severe colitis, requirement of IV steroids, oesophageal disease

UC: requirement of IV steroids

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19
Q

Indication for methotrexate in IBD

A

Intolerance or unresponsive to thiopurines

TMPT heterozygotes

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20
Q

Malignancy risk associated with infliximab

A

Hepatosplenic T cell lymphoma

  • 76 cases described
  • All received concurrent Aza therapy
  • High mortality
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21
Q

General complications of liver disease

A
  1. Ascending cholangitis
  2. Nutritional deficiency
  3. Fat soluble vitamin + zinc deficiency
  4. Portal hypertension
    - Hypersplenism - thrombocytopenia
    - Varices
  5. Synthetic liver dysfunction
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22
Q

Management of hepatitis B to prevent neonatal acquisition

A
  1. Pretreat mother antenatally to reduce viral load (tenofovir)
  2. HBIG and vaccination at birth + vaccination at 6wk/3mo/5mo (97% protection)
    - Vaccination at birth provides 65-95% protection
  3. After 5mo vaccination, reassess infant: HBsAg and anti-HBs

2-3% acquire Hep B despite above measures
2-3% do not respond to vaccine

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23
Q

First line agent for hepatitis B

A

Entecavir:

  • Oral agent
  • Nucleotide analogue - effective at suppression of viral replication
  • Well tolerated
  • Cons: unresolved question about length of treatment
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24
Q

NAFLD - pathophysiology

A

Excessive caloric intake + insufficient energy expenditure

  • Increased adiposity (increased fat deposition in liver)
  • Hyperinsulinism –> need more insulin to get glucose into cells, lipogenesis
  • Fat causes inflammation –> secondary to metabolic stress and mitochondrial dysfunction
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25
Q

KASAI procedure (hepatoportoenterostomy)

A

Palliative procedure
Success depends on:
1. Age at operation
- <30 days - best outcome, longer transplant free survival
2. Experience level of surgeon (>5 Kasai procedures/year)

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26
Q

Percentage requiring liver tranplantation in biliary atresia

A

80-90%

Approx 40% of these transplants are required in the first 2 years post-Kasai procedure

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27
Q

Contraindication to Kasai procedure

A

Frank liver failure

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28
Q

Complications of Kasai procedure

A
  1. Ascending cholangitis
    - Liver and biliary flow directly exposed to intestine and its contents
    - Associated with worse outcome
  2. Portal hypertension
  3. Growth failure
  4. Hepatopulmonary syndrome
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29
Q

Familial adenomatosis polyposis - risk of malignancy

A

Average age of onset of polyps = 16yrs
100% develop malignancy
If no prophylactic colectomy, average age of onset of colorectal Ca is 39yrs

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30
Q

Fibrosing colonopathy - CF

A

Colonic strictures with mucosal and submucosal fibrosis, destruction of muscularis mucosa

Increased risk with high dose pancreatic enzyme replacement

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31
Q

Most common causes of pancreatic insufficiency

A
  1. Cystic fibrosis
  2. Syndromes
    - Shwachman-Diamond Syndrome (acinar cell hypoplasia, intact ducts; skeletal abN)
    - Pearson Syndrome (pancreatic cell atrophy w/ fibrosis –> reduced acinar and duct function)
    - Johanson-Blizzard Syndrome (acinar cell hypoplasia, intact ducts; no bone marrow abN)
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32
Q

Shwachman-Diamond Syndrome increases risk of…

A

AML

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33
Q

Benefits of fish-oil based lipids

A
  1. Less inflammatory
  2. Increased antioxidant activity
  3. Decrease phytosterols
  4. Increase biliary flow
  5. Decrease de novo lipogenesis
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34
Q

RF for intestinal failure associated liver disease (IFALD)

A
  1. Prematurity and low birth wt
  2. Primary GI disease e.g. NEC
  3. Lack of enteral nutrition
  4. Catheter-related bloodstream infections
  5. Small bowel bacterial overgrowth
  6. Prolonged TPN
  7. Excessive IV glucose, amino acids or omega-6 fatty acids
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35
Q

Management of IFALD

A
  1. Cycling of TPN - introduce breaks between therapy if pt able to cope nutritionally (TPN wean is most important)
  2. Urso (increase enterohepatic circulation)
  3. Advancement of enteral feeding
  4. Prompt treatment of sepsis
  5. Ethanol and Ab line locks
  6. Rotating Ab prophylaxis for SBBOG
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36
Q

GLP-2 analogue: Teduglutide

A

Trophic hormone secrted by enteroendocrine L cells (ileum and R colon) - increases villous height and serum citrulline levels

Result: reduces TPN requirements in pts with short gut syndrome

Clinical trials in paediatrics underway

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37
Q

Intestinal failure definition

A

Anatomical loss of >75% of expected small bowel length for gestational age
OR
TPN dependence >42 days

Reduction in gut function, such that IV supplementation is required to maintain health and/or growth

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38
Q

Aetiology of intestinal failure

A
  1. Critical reduction in intestinal mass:
    - Short bowel syndrome
  2. Poor tolerance of feeds
    - Motility disorders: gastroschisis, chronic intestinal pseudo-obstruction, long-segment Hirschprung Disease
  3. Abnormal enterocyte function
    - Microvillus inclusion disease, tufting enteropathy
  4. Multisystem disease
    - IPEX, mitochondrial disorders, congenital glycosylation defects
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39
Q

Hereditary disorders causing pancreatitis

A

Candidate gene and genetic linkage studies have identified polymorphisms in:

  1. Cationic trypsinogen gene (PRSS1)
  2. Serine protease inhibitor kazal type 1 (SPINK1)
  3. CFTR
  4. Chymotrypsinogen C (CTRC)
  5. Cathepsin B (CTSB)
  6. Calcium sensing receptor (CASR)
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40
Q

Treatment for Ascariasis lumbricoides

A 
4 drugs recommended by WHO:
1. Albendazole
2. Levamisole
3. Mebendazole
4. Pyrantel embonate
All 4 have a cure rate of >90% in pts with ascariasis
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41
Q

Mycophenolate Mofetil: MOA and SE

A

Inhibits synthesis of guanosine monophosphate nucleotides, blocks purine synthesis preventing proliferation of T and B cells

SE: diarrhoea, cytopenias, N&V, thrombosis/thrombophebitis in IV formulation

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42
Q

KCal in CHO, protein and fat

A

4-4-9 rule
CHO: 4cal/gram
Protein: 4cal/gram
Fats: 9cal/gram

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43
Q

Management of DIOS

A
  1. Hydration
  2. Laxatives
  3. Bowel washout
  4. Prokinetics
  5. +/- Surgery
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44
Q

Intestinal adaptation in short bowel syndrome

A

Structural: hyperplasia, angiogenesis, bowel dilatation and elongation
Functional: increase transporters, accelerated crypt cell differentiation, slowing transit time, increased nutrient and fluid absorption

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45
Q

Factors that promote enteral autonomy in short bowel syndrome

A
  1. Residual small bowel length
  2. Intact ileocaecal valve
  3. Primary diagnosis of NEC
  4. > 50% residual colon
  5. No small bowel ostomy
  6. Decreased serum conjugated bilirubin at referral
  7. Care and follow up at same centre specialising in intestinal rehabilitation
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46
Q

Preventative treatment option for pre-symptomatic siblings with Wilson’s disease (identified on genetic testing)

A

Zinc supplementation

  • Competitive inhibitor of copper, helps displace copper from tissue and increase excretion in urine
  • Zn alone is insufficient to treat symptomatic Wilson’s disease
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47
Q

Wilson Disease Treatment

A
  1. Penicillamine +/- pyridoxine (Pen causes Vit B6 def)
  2. Trientene as an alternative if Pen not tolerated
  3. Zinc supp and low copper diet
  4. If fulminant liver failure or decomp cirrhosis, liver transplant is necessary
    - -> May not ameliorate neurological Sx as Cu deposits in basal ganglia
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48
Q

Splenomegaly with thrombocytopenia can be a manifestation of…

A

Portal hypertension

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49
Q

Some quirks in investigation result of different liver diseases…

A
  • Wilson disease: low ALP (Cu displaces Zn)

- Autoimmune hepatitis: high total protein due to hypergammaglobulinemia

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50
Q

Antibodies associated with autoimmune hepatitis

A 
Liver:
- Type 1: ANA +/- SMA
- Type 2: LKM (2a: no hep C, 2b: yes hep C)
- Type 3: soluble liver antigen
Biliary tree (sclerosing cholangitis)
- ANA, SMA, ANCA
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51
Q

Liver conditions that can recur despite liver transplantation

A

Autoimmune hepatitis

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52
Q

Poor prognostic indicators of autoimmune hepatitis

A
  • Type II disease
  • Younger age at presentation
  • Coagulopathy
  • Jaundice at presentation
  • Severe biopsy findings
53
Q

Associations with secondary sclerosing cholangitis

A
  • Cystic disease (Carolis disease)
  • Chemical cholangitis (CFLD)
  • Choledocholithiasis (Haemolytic anaemias - pigment stones)
  • Previous hepatobiliary surgery
  • Immunodeficiencies
  • -> X-linked hyper-IgM syndrome assoc. with cryptosporidium
54
Q

2 main causes of echogenic liver

A
  1. Fat storage within the liver - fatty liver disease

2. Glycogen storage within liver - GSD

55
Q

Factors predicting mortality after liver transplantation

A
  • Encephalopathy
  • Male gender
  • Assisted ventilation prior to transplant
  • Seizures post-transplant
56
Q

Liver biopsy findings on biliary atresia

A
  • Bile ductular proliferation
  • Intracanalicular bile plugs
  • Giant cells
    +/- fibrosis
57
Q

Good prognostic indicators for biliary atresia

A
  • Kasai procedure within 30 days of life (very few can have transplant-free survival)
  • Performed at a centre that does >5 kasai/year
  • Re-establishment of bile flow and resolving jaundice
  • -> Cirrhosis develops more slowly
58
Q

Bad prognostic indicators for biliary atresia

A
  • Presenting in frank liver failure
  • Failure to re-establish bile flow post-kasai
  • Persistent jaundice despite kasai
  • Ascending cholangitis
59
Q

DDx for biliary atresia

A
  • Alagille syndrome (AD)
  • A1AT (co-dom)
  • CMV infection
  • Progressive familial intrahepatic cholestasis (AR)
  • Galactosemia
60
Q

Hepatosplenomegaly in biliary atresia

A
  • An indication of progressive cirrhosis with portal hypertension
61
Q

Aim of Kasai procedure

A
  • Resume bile flow (bile duct microchannels >150mirom have greater chance of success), decompress the liver, delay onset of cirrhosis and sustain growth before planning for liver transplant (almost inevitable)
62
Q

Risk factors for hepatocellular carcinoma

A
  • Viral hepatitis (C)
  • Glycogen storage disorder
  • Tyrosinemia
  • PFIC type 2
  • Cirrhosis (secondary to other disease)
63
Q

Management of pancreatitis

A
  1. IV fluids
  2. Parenteral analgesia
  3. NBM
  4. Commence low-fat feeds when pt improving and wishes to eat
  5. No antibiotics
    - Severe pancreatitis: transpyloric tube feeding wiht semi-elemental formula recommended very early in course of therapy
64
Q

RF for portal vein thrombosis

A
  • Umbilical catheterisation in neonates
  • Protein C, Protein S and antithrombin III deficiencies
  • Anticardiolipin Abs
  • Pancreatitis
65
Q

Aims of treatment of Hepatitis B

A
  • Control viral response
  • E Ag negative state
  • sAb positivity
66
Q

Chronic hepatitis B/carrier - serology

A
  • Chronic active HBV: positive HBsAg, Anti-HBc +/- HBeAg

- Chronic carrier (inactive): positive HBsAg, Anti-HBc

67
Q

Remote/past hepatitis B - serology

A
  • Positive Anti-HBsAg, anti-HBcAg
68
Q

Active hepatitis B/window period - serology

A
  • Active: Positive HBsAg (early), HBeAg, HBc IgM (window)

- Window: positive HBc IgM

69
Q

Hepatitis B treatment: Entecavir

A
  • Oral agent
  • Nucleotide analogue - effective at suppressing virus
  • Well tolerated, but unclear duration of therapy
70
Q

Hepatitis B treatment: Interferon

A
  • 58% response
  • Weekly subcut injections
  • Pros: more durable response, fixed duration of treatment, lack of resistant strains
  • Cons: subcut, expensive, SE (flu-like Sx, BM suppression, anorexia depression)
71
Q

Hepatitis B treatment: Lamivudine

A
  • 23% response in children c.f. 15% in placebo
  • Pros: oral, cheap, well tolerated
  • Cons: increased risk of drug resistance - 70% by 5yrs, less durable response
72
Q

Paracetamol dose threshold for hepatic injury

A
  • Acute single: >200mg/kg or 10g (whichever less) over period of <8hrs
  • Repeated ingestions:
  • -> >200mg or 10g over 24hr period
  • -> >150mg or 6g over 24hr period for preceding 48hrs
  • -> >100mg or 4g/day in pts with predisposing factors (prolonged fasting, dehydration, other enzyme-inducing drugs)
73
Q

Paracetamol kinetics in liver

A
  • 20% of paracetamol metabolised by small intestines, 80% metabolised by liver
  • Liver: 90% metabolised to inactive sulphate + glucuronide conjugates –> excreted in urine. Remainder metabolised by cytochrome P450 (2E1, 3A4) to form highly toxic NAPQI
  • NAPQI usually mopped up by glutathione –> excretes into urine –> does not cause hepatic injury
74
Q

Pathophysiology of paracetamol OD

A
  • Supratherapeutic doses cause +++NAPQI –> saturates glutathione stores by 70-80%
  • NAQI disrupts oxidative phosphorylation –> reduced ATP, lactic acidosis and release of Ca from mitochondrial stores –> apoptosis and necrosis of hepatocytes
  • Superoxide anion form’n –> oxidative damage
  • NAC infusion: converted to glutathione to mop up NAPQI, cysteine (midproduct) supplies sulphate to convert paracetamol for urinary excretion
75
Q

Risk of requiring liver transplant in paracetamol OD

A
  • Repeated supratherapeutic doses over prolonged period
76
Q

RF of severe liver damage and death

A
  • Extent of delay beyond 8hrs before commencement of NAC infusion
77
Q

Is it beneficial to start NAC infusion in a pt in fulminant liver failure beyond 8hr window?

A
  • Yes
  • It can still reduce mortality
  • Reduces risk of cerebral oedema, inotrope requirements and increases survival rates by 30%
78
Q

Timeline of events in paracetamol overdose

A
  • Usually asymptomatic over first 24hrs
  • 24-72hrs: RUQ pain, LFT derangement, prolongation of INR and PT
  • 72-96hrs: fulminant liver failure, coagulopathy, multisystem organ failure
  • 96hrs-14 days: die or survive + recover
79
Q

Best marker for potential for injury after paracetamol OD

A
  • Timed serum paracetamol level plotted on nomogram
80
Q

Other markers of IBD

A
  • Gene associated w/ IBD: NOD2 - regulates monocyte response to antigens
  • p-ANCA positive in 70% with UC
  • Anti-Saccharomyces cerevisiae Ab found in 55% with CD
81
Q

Crohn’s disease presentation

A
  • Transmural inflammation with skip lesions from mouth to anus, includes perianal disease
  • Fistulising, stricturing disease with granulomas
  • PC: abdo pain with RIF mass (consider perforation), perianal diz with fissures, fistulas, abscesses which can cause stenosis; orofacial granulomatoses, aphthous ulcers, angular cheilitis, erythema nodosum and pyoderma gangrenosum
82
Q

Indicators of bleeding (colitis) in IBD

A
  • Low Hb

- Low albumin (also might indicate small bowel involvement in CD)

83
Q

MOA of azathioprine

A
  • Active metabolite 6MP further metabolised to 6-MMPR which inhibits de novo purine synth and thioguanine nucleotide which incorporates into DNA –> inhibits proliferation of lymphocytes, causes apoptosis
  • TPMT enzyme facilitates 6MP down 2 different pathways –> it inactivates it (controls amount of drug) and also converts it to 6-MMPR
84
Q

SE of azathioprine

A
  • Myelosuppression (6TG - dose dependent)
  • -> Mild lymphopenia is acceptable
  • Idiosyncratic reaction (pancreatitis)
  • Infection risk
  • Hepatitis (6-MMP)
  • Malignancy - 4-fold increased risk of lymphoma
85
Q

TNF-a

A
  • Pro-inflammatory cytokine, particularly damaging in Crohn’s disease
  • TNF-a inhibits insulin-like growth factor and downregulates growth hormone receptor
86
Q

Manifestations which correlate with disease activity in IBD

A
  • Erythema nodosum
  • Anaemia
  • Type 1 Peripheral Arthropathy (oligoarticular)
87
Q

Formula for daily kcal requirement under basal conditions

A

100kcal/kg for first 10kg
50kcal/kg for next 10kg
20kcal/kg for rest of wt
(Like maintenance fluids)

88
Q

Associations with infectious diarrhoea

A
  • Recent travel: toxigenic E. coli, Giardia
  • Fever with high WBC: shigella
  • HUS: E. coli 0157:57
  • Swimming in lakes or drinking well water: Giardia
  • Consumption of pork/intestines: Yersinia
89
Q

DDx for refractory constipation

A
  • Hypothyroidism
  • Hypocalcemia
  • Coeliac disease
  • Spinal dysraphism
  • Hirschprung’s disease (empty rectum)
  • Fanconi Syndrome/other causes of significant electrolyte disturbances
90
Q

Most common type of TOF

A

Upper oesophageal atresia with distal tracheo-oesophageal fistula

91
Q

VACTERL association

A

Vertebral anomalies
Anal atresia
Cardiac - PDA, VSD, ASD
TOF
Renal - urethral atresia with hydronephrosis
Limb anomalies - humeral hypoplasia, radial aplasia, hexadctyly, proximally placed thumb

92
Q

Ingestion of toxic products: alkali agents

A
  • Liquefactive necrosis with intense infalmmation

- PC: drooling, dysphagia, abdominal discomfort, airway Sx e.g. stridor, retractions

93
Q

Most common sites for foreign body lodgement in the oesophagus

A
  • Thoracic inlet (60-80%)
  • Gastro-oesophageal junction (10-20%)
  • Level of aortic arch 5-20%
94
Q

Conditions associated with intestinal malrotation

A 
Asplenia/polysplenia/heterotaxy syndrome 
Atrial isomerism 
Congenital diaphragmatic hernia 
Duodenal/jejunoileal atresia 
Oesophageal atresia/TOF
Gastroschisis/omphalocoele 
Hirschsprung disease, intestinal pseudo-obstruction 
Intussusception
95
Q

Gardner Syndrome

A
  • Mutation on APC gene
  • Supranumery teeth, GI polyps (hundreds of adenomatous polyps) and osteomas
  • Soft tissue tumours inc desmoid, sebaceous and epidermoid cysts, lipomas
  • Osteomas of skull, maxilla and mandible
  • Congenital hypertrophy of retinal pigment epithelium
96
Q

Hirschprung Disease - extent of involvement

A
  • 75% begin at the anus and extend proximally to sigmoid
  • 8% have entire colonic involvement
  • Even small number involve small intestines
97
Q

Risk of an affected sibling with Hirschprung Disease inheriting the disease

A

7%

98
Q

Associations with HD

A 
Down syndrome
Laurence-Moon-Bardet-Biedl syndrome
Smith-Lemi-Opitz syndrome
Waardenberg Syndrome
CCHS
99
Q

Genes/factors that affect migration of neural crest cells to distal intestines

A

Hox and Sox homeobox genes

Glial-derived enurotrophic factor and endothelin receptor B/endothlin 3

100
Q

Diagnosis of HD

A
  • Suction rectal biopsy
  • Absence of any ganglion cells in a bx containing adequate mucosa
  • -> Absence of submucosal (Meissner) and myenteric (Auerbach) plexuses and hypertrophied nerve bundles with high concentrations of acetylcholinesterases between muscular layer and submucosa
101
Q

Microvillus Inclusion Disease

A
  • Severe intractable secretory diarrhoea from birth
  • MYOB5 gene mutation in some with early onset MVID
  • Villous hypoplasia and diffuse thinning of mucosa with no inflammatory cells
  • PC: polyhydramnios, severe secretory diarrhoea >200ml/kg/day with electrolyte imbalances, dehydration and FTT
  • Mx: TPN, intestinal transplantation
102
Q

Tufting enteropathy

A
  • EPCAM gene mutation - abnormality in integrin protein disrupting cell-cell and cell-cell matrix signalling
  • Intestinal mucosal dysplasia focal epithelial tufts, which may not be present from birth (often misdiagnosed as autoimmune)
  • PC: severe intractable diarrhoea in the first few weeks of life
  • Mx: TPN and intestinal transplant
103
Q

Congenital chloride diarrhoea

A
  • SLC26A3 gene - Na independent Cl/HCO3 exchanger within apical membrane of ileal and colon
  • Presents with severe secretory diarrhoea in first few weeks of life
  • Metabolic alkalosis, hypochloremia, hypokalemia, hyponatremia
104
Q

Effects of intestinal lymphatic obstruction (e.g. due to ectasia)

A
  • Lymphatic loss into gut or peritoneal cavity –> loss of protein, fat, fat-sol vitamins and lymphocytes
  • Impairs lymph flow –> increased P in intestinal lymphatics leads to leakage of lymph into intestinal lumen, reduced recirculation of intestinal lymphocytes into peripheral circulation and decreased absorption of fat-soluble vitamins
  • Oedema, growth failure, steatorrhea, immune def
  • HypoCa and hypoMg as cations complex with unabsorbed fatty acids in gut –> pass in poo
105
Q

Stool test results in intestinal lymphatic obstruction

A
  • Positive A1AT

- Positive for both fat globules and crystals

106
Q

Coeliac disease and HLA

A

HLADQ2 and HLADQ8

107
Q

Coeliac disease histology

A
  • Intraepithelial lymphocytes
  • Villous atropy/loss
  • Crypt elongation
  • Loss of brush border, abnormal flattening of epithelial cells
108
Q

Atypical presentation for coeliac disease

A

Psychiatric symptoms: common in females

  • Anxiety, depression
  • Anger, moodiness, impatience
109
Q

Coeliac disease diagnosis

A
  • Anti-TTG IgA x10 ULN
    (in pts with normal IgA levels)
  • Anti-endomysium Ab + (on separate collect)
  • Small intestinal biopsy (not required in some places if above are positive)
110
Q

Indications for repeat scope/formal challenge

A
  • If Dx made at <2yo
  • If initial biopsy was inadequate/Bx not taken
  • Clinical response is equivocal
  • Screened pts i.e. no symptoms
111
Q

Anti-TTG monitoring of disease activity

A
  • Normalise on treatment after 6-12mths
  • Monitoring of compliance after 1yr
  • CLINICAL improvement occurs in 3wks
112
Q

Complications of coeliac disease

A
  • Bone disease: osteopenia
  • Malignancy risk: lymphoma&raquo_space; oropharyngeal, oesophageal, liver
  • Decreased fertility
    These risks are reduced when gluten free diet is introduced
113
Q

Oesophagus muscle structure

A
  • Upper 1/3 = striated muscle (excitatory neurons)
  • Lower 2/3 = smooth muscle (inhibitory neurons)
  • Stratified squamous epithelium (non-keratinised)
114
Q

Achalasia and viral association

A

Can be secondary to autoimmune process with latent infection of HSV1 in genetically susceptible individuals

115
Q

Consequences of GORD

A
  • Oesophagitis: dysphagia
  • Irritability and excessive crying
  • Malnutrition
  • Haematemesis
  • Recurrent aspiration –> pneumonia
  • Other associated respiratory events
116
Q

Eosinophilic oesophagitis

A
  • Atopy occurs in 80%
  • Peripheral eosinophilia in 50%
  • Endoscopy: radial furrowing with longitudinal tram tracking, >20 eosinophils/hpf
  • PC: food bolus that is episodic (often occurs at transition of striated to smooth muscle)
117
Q

Management of eosinophilic oesophagitis

A
  • Food elimination diets: elim of 4 or 6 food groups causes dramatic improvements in eosinophils –> worse again on challenge
  • -> Wheat, cow’s milk, soy milk, nut, fish, egg
  • High dose PPI effective in 10%
  • Steroid therapy
  • -> Fluticasone or budesonide - need to swallow
  • Leukotriene receptor modifiers are meh
118
Q

Cells and hormones of the stomach

A
  • Parietal cells: release H+ via H/K-ATPase
  • Chief cells: release gastric lipase, pepsinogen –> pepsin in acidic environment
  • G cells: secrete gastrin
  • D cells: secrete somatostatin
  • Mucous neck cells: secrete mucus to protect gastric lining from acid and pepsin
119
Q

Control of the parietal cell

A
  • Under control of the vagus nerve –> ACh
  • ACh stimulates parietal cells directly - M3 receptor
  • ACh stimulates G cells and endochromaffin-like (ECL) cells –> gastrin binding to CCK-b receptor, histamine binding to H2-receptor respectively
  • ACh, gastrin and histamine promote H+ secretion
  • D cells release somatostatin - inhibits H+ secretion with prostaglandins
120
Q

Cell signalling pathways involved in parietal cell control

A
  • Gastrin and ACh act via IP3 signalling pathway

- Histamine increases cAMP and somatostatin + prostaglandins decrease cAMP

121
Q

Malignancies associated with H. pylori infection

A

Gastric MALT lymphoma

Gastric adenocarcinoma

122
Q

Pathophysiology of H. pylori infection

A
  • H. pylori ingestion (cagA and vacA+) –> gastric antral colonisation - initially decreases acid secretion (low Cl-)
  • Active gastritis mediated by macrophages –> loss of normal inhibition control of acid secretion
  • Chronic superficial gastritis secondary to hypergastrinemia and reduced D cell population and/OR
  • Duodnenal gastric metaplasia –> hypergastrinemia
  • Can lead to gastric or duodenal ulceration, atrophic gastritis
  • Atrophic gastritis –> intestinal metaplasia –> possible malignancy
123
Q

Most common trigger of FPIES

A

Cow’s milk and soy (can cross-react)

124
Q

Major milk allergen in cow’s milk

A

B-lactoglobulin

Caseins

125
Q

Most common solid food trigger of FPIES (and related consequences)

A

Grains (esp. rice)
Solid food induced FPIES is more likely to have protracted course, children are more likely to require IV fluid resuscitation
Occurs in older infants 4-7mths when solids are introduced

126
Q

Acute management of FPIES

A
  • IV fluid resuscitation
  • IV methyprednisolone
    +/- IV ondansetron has shown to be effective in small #
127
Q

Best non-invasive predictors of portal HTN

A

Platelet count
Spleen length
Serum albumin

128
Q

Pharmacological therapy to decrease portal pressure during haemorrhage

A
  1. IV vasopression - increases splanchnic vascular tone and decreases portal vein flow
  2. Nitroglycerin patch - decreases portal pressure
  3. Octreotide - somatostatin analogue which decreases splanchnic blood flow with fewer side effects

Paediatrics (16 decks)

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