Investigations Flashcards
What Faecal Investigations exist?
What are they looking for>?
Fecale Elastase 1 test- screen for pancreatic exocrine insufficency - (should be >100ug/g, if not then pancreas not secreting enough elastase) - good assessment of pancrease activity in cystic fibrosis
Must be secreted under command of CCK (In diarrhoea and intestinal atrophy may give false positive for failure of signal to pancreas)
May also use SERUM trypsinogen as screening for PEI
Alpha-1 anti-trypsin = Screen for protein losing enteropathy - similar molecular weight to albumin but resistant to digestion - excessive levels cause of gut/stomach loss (Menetrier disease) (SHOULD BE LOW, if present - PLE)
Hydrogen Breath Tests?
Malabsoprtion causes fermentation of culprit carbohydrate in large bowel
Bacteria produce hydrogen - found on breath (>20ppm is positive)
FRUCTOSE def. - 5% of population due to reduced GLUT -5 Transporter
How to Dx Meckles?
Meckle scan - Technetium 99m pertechnetate
85% Sensitive
95% Specific
// Other = Radiolabeled tagged red blood cells (but must be actively bleeding) Ultrasound Superior mesenteric angiograpahy Abdominal CT Exploratory Lap
(Plain X-ray useless)
(Contrast rarely fills diverticulum)
Alpha 1 Antitrypsin - What test to order?
Do alpha-1-AT Phenotyping : “Protease Inhibitor Phenotype System “Pi__”
PIMM Normal
PIMZ Normal
So PIZZ is super low
PISZ can also cause damage
Gene on chromo 14q
Why not just a level? In deficiency is structurally unable to leave hepatocyte (and protect lung from leucocyte elastase) - eventually liver damage ensuse and hepatocytes lyse - then you can’t tell if serum alpha-1-antitrypsin represents ANYTHING
Unless Null-Null variant then actually 0 - but this won’t cause any LIVER disease, just lung
Alpha 1 Anti-Trypsin
Acholic Stools Mimics billary atresia Eventually do a cholangiogram and that diffentiates - 25% early liver 25% cirrhosis 50% do well +/- chronic hepatitis
The other 10 % will get liver disease in later life by 40 yrs
The rest just always have a slightly elevated ALT in the 100-200 range
Liver Bx for alpha 1 antitrypsin findings?
Accumulate protein - Period Acid Schiff granules - accumulation inside hepatocytes
= +/- inflammation/cirrhosis etc.
What is a HIDA scan and why to do it?
I dunno yet, look it up
Wilson’s Disease?
Autosomal Recessive Chromosome 13
Carrier 1:90 - therefore 1:30,000
ATP7-BETA - COPPER TRANSPORT
ATPase
Incorporates into Ceruloplasmin for serum
And binds to copper to go into bile
Accumulates in HEPATIC in CHILDREN more NEUROLOGICAL in adults - Could be psychotic or asymptomatic
Chronic Hepatitis - like autoimmune hepatitis - but doesn’t get better
Asymptomatic LFT
Portal Hypertension
Acute Liver Function with haemolytic anaemia (coombs -ve)
Liver Failure and Haemolysis ++ in a ~ 10 year old
WILSONs!
Scoring system (Bili, INR, AST, WCC< Albumin)
Higher Bili due to haemolytic anaemia
Probs need a Liver Tx - hepatic necrosis
Kaiser Fleischer ring
Will (100%) have some neurological (school performance, driving) and likely hepatic (85%)
- Copper deposition around Descemet’s Membrane
Wilson’s Disease Neuropyschiatric?
Will progress to bradykinea, rigitid, cognitive impairment, mood syndrome
Ataxia Tremor(thalamic)
Dyskinesia, Dysarthria, Organic personality syndrome (putamen and pallidum)
But not as 1st pres very often in kids
Diagnosis of Wilsons
LIVER DIAGNOSIS (unexplained transaminase, portal HTN, cirrhosis) and 2 of:
Positive Family History
Low Serum Caeruloplasmin (0.2g/L)
Elevated Liver Copper (250mg/g dry weight) (Will +ve with any cholestasis)
Presence of Kayser-Fleischer Rings
Elevated baseline 24 hour urinary copper (1 micromol/24hours)
Elevated urinary copper after 2x 500-mg penicillamine (SUPER - 25 u/mol/24)
Coombs NEGATIVE haemolytic anaemia (Only in acute liver failure, not chronic)
GENETICS
WILSONs Treatment
D-Penicillamine - Chelator and urinary excretion- inital neurological worsening - then skin++, muscle, bone marrow side effects
Trientine Chelator and urinary excretion- Less autoimmune but also sideroblastic anamie
Zinc Acetate - Blocks copper absorption in gut by inducing mettalothionein in enterocytes
// Low copper diet
// Liver Transplant - corrects the defect //
Screen Family members for genetics
PREVENTS SEVERE ACCUMULATION
NAFLD?
Fatty liver changes secondary to INSULIN resistance in (mostly) fat children.
Leading cause of chronic liver disease (in USA) -
3% of adolescents will have biochemical/LFT changes
Of those, 1:10 histological change
// Genetic and Diet and Stress -> Insulin Resistance
ALT ~ 100, AST ~ 65 Mild ALT rise - Steatosis to liver Isolated hepatomegaly Not so much Chronic Liver Disease // Risk Factors - Obesity Acanthosis Nigricans 30-50% (Marker of insulin resistance) OSA T1/T2 DM //
STEAOSIS + Inflammation = NASH
NASH = Hepatitsi = INFLAMMATION , separate to NAFLD (no inflammation)
NASH can progress to fibrosis
Fibrosis can progress to cirrhosis
// Rule out WILSONs, Rule out alpha1antitrypsin // Bright Liver - echogenic Big liver // MultiDisciplinary Aprroach Medical/Dietician/Psychology/Physio/Physiology >5Kg sometimes sufficient to reverse insulin resistance . \+ Vitamin E 800 units/day \+/- Surgery
Liver Disease - If not autoimmune, wilsons, alpha 1, NASH billary anatomical ?
Inborn Error of Metabolism
Single Enzyme
Abnormal catabolism
Accumulation of toxic
- Liver Failure in NEONATE
Galactosaemie
Tyrosinaemaie
- STOP FEEDS and Ix
2.Encephalopathy- Too much ammonia Urea Cycle Defect Fatty Acid Oxidatinon Disorder Orgainc Acidemia Fatty Acid Oxidation
3.Chronic cholestasis Mostly in Neonatal - alpha 1 AT< Neonatla haemochroma Bile acid syntheis erro Niemann Pick Peroxisomal function Congenital disorders of glycosylation “Bloating” - actually hepatomegaly Big liver (glycogen for example) Big spleen (probs not glycogen, more like lyposomal)
