Gastroenterology (Medical Abdo) Notes

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Gastroenterology (Medical Abdo) Notes
Liver
Palpable liver edge:
Normal
Hepatomegaly
Lung hyperexpansion
Friction rubs:
1Y and metastatic malignancies
Post-liver biopsy
Infective and inflammatory conditions
Venous hum:
Portal venous HTN
Arterial bruit:
Liver tumours
Alcoholic hepatitis
Small liver:
Cirrhosis
Fulminant hepatic failure
Chronic liver disease
Hepatomegaly: Massive:
Alcoholic fatty infiltration
Myeloproliferative disorders
Mets
Hepatoma
R heart failure
Moderate:
Haemachromatosis
CML / lymphoma
Diabetic fatty liver
Tropical disease (eg. malaria, schisto)
Mild:
Infections (eg. EBV, CMV, hep)
Hydatid disease
Sarcoid / amyloid
Splenomegaly:
Massive:
CML
Myelofibrosis
Malaria (acute)
Kala azar
Moderate:
Portal HTN
Lymphoma / leukaemia
Thalassaemia
Storage disease
Schistosomiasis
Brucellosis
Typhoid
Mild:
Infections (eg. EBV, CMV, SBE)
Haemolytic anaemia
Polycythaemia rubra vera
CT disorders (eg. RA, SLE, PAN)
Sarcoid / amyloid
Chronic liver disease: Limbs:
Duputren’s contracture
Palmar erythema
Clubbing
Easy bruising
Scratch marks
Peri oedema
Metabolic flap
Head:
Jaundice
Parotid enlargement
Xanthomata (1Y bil cirr, scelr cholang)
Encephalopathy
Chest:
Abdo:
Portal HTN:
Gynaecomastia
Spider naevi (>5 abnormal)
Dilated superficial veins
Ascites
Splenomegaly
Hepatomegaly
Splenomegaly
Venous collaterals
Ascites
Murphy’s sign: Inability to deep inspire due to RUQ pain
= acute cholecystitis: sensitivity 97%, specificity 50%
Kehr’s sign:
Severe L shoulder tip pain esp when lying supine
= haemoperitoneum
Cullen’s sign:
Periumbilical ecchymoses
= retroperitoneal haemorrhage
Grey-Turner’s sign:
Flank ecchymoses
= retroperitoneal haemorrhage
McBurney’s sign:
Tenderness 2/3 distance from umbilicus to R ASIS
= appendicitis
Iliopsoas sign:
AP on extension of R hip
= appendicitis: 16% sensitivity, 95% specificity
Obturator’s sign:
AP on internal rotation of flexed R hip
= appendicitis
Rovsing’s sign: RLQ pain and palpation LLQ
= appendicitis
Heel-drop sign: RLQ pain on dropping heels to ground when on tiptoe
= appendicitis: 93% sensitivity
Cough test:
AP after cough
= appendicitis: 95% sensitivity
Gastroenteritis
3+ abnormally loose BM’s over 24hrs
Sx: vomiting ++ if pre-formed toxin; prominent AP if invasive
Doses:
Norfloxacin 400mg (10mg/kg) PO BD 5/7
Alternative: ciprofloxacin, cotrimoxazole, ampicillin
- E coli, Campylobacter,
Yersinia, salmonella,
shigella
- Cholera
Doxycycline
Alternative: tetracycline
Metronidazole 400mg (10mg/kg) PO TID 7-10/7
Vancomycin 125-250mg PO QID 10/7
Erythromycin 500mg (10mg/kg) PO QID 5/7
MO
Incbn
DOA
Source
- C diff, giardia
- Severe C diff
- Campylobacter
Specific symptoms
Antibiotics?
Pre-formed toxin
Bacillus cereus
1-6hrs
<24hrs
Staph aureus
1-6hrs
<24hrs
Rice, cereal,
soup, veggies,
meats, pasta
Cold foods,
sweetened dairy
products
Vomiting ++
May be delayed onset form
At 8-18hrs, AP + D but little V
Vomiting ++
 diarrhoea, AP  dehydration
No
Many raw foods
0157:H7  Shiga  bloody watery
stools without WBC
Debatable
 TTP, HUS
Norfloxacin if severe
(but may CAUSE HUS)
No
Post-formed toxin
E Coli
(20-75%)
(Most common cause
of traveller’s
diarrhoea)
Clostridium
perfringens
(25% all bacterial)
Vibrio cholera
(0-30% travellers)
C difficile
Toxins A and B;
secretory
Varies
(usually
1-5/7)
Dayswks
6-12hrs
<24hrs
Hrs-days
2-7/7
7-10/7
after
ABx
Meat and
poultry, soil,
manure, sewage
Shellfish
Antibiotics
Clindamycin
Ampicillin
Amoxicillin
Cephalosporin
1-25% colonisation in
hospitalized patients
Diarrhoea, AP
Severe rice water diarrhoea,
headache, N+V
Severe:
Pseudomembranous enterocolitis
(RF inc recent ABx, recent GI surgery,
co-morbidities, chemo, old age)
or any 2 of: >60yrs; T >38.4, alb
<2.5mg/dL; WBC >15
YES NEEDS ABX:
Metronidazole
Vancomycin if severe
Fulminant (3-8%):
Toxic megacolon, systemic
manifestations (eg. incr WBC,
hypotension, MOF, anascara)
Listeria
Doxycycline if in 1st
48hrs
Stop offending ABx
Days wks
Meat, cheese
1-3% get toxic megacolon or perf
Relapse in 10-25%
Flu like  meningitis, septicaemia,
miscarriage, prem birth
Emergency colectomy if
fulminant
Bad if pregnant / neonate
/ immunosupp / elderly
Enteroinvasive
Salmonella
(0-33% travellers)
12-24hrs
Up to
3/52
Dairy, eggs, raw
meat, raw
veggies
Can cause bloody diarrhoea, systemic
illness
In children can cause osteomyelitis,
meningitis
If septicaemia /
immunocompromised /
infant / elderly / multiple
co-morbidities
Norfloxacin if severe
IV ceftriaxone if <3/12
Shigella
2-30% travellers
(also release cyto,
neuro and
enterotoxins)
12-96hrs
4-7/7
Infected foodhandler or
water; poor
sanitation;
traveller; child
care centres
Poultry, milk,
pets with
diarrhoea
Campylobacter
Jejuni
(3-17% travellers)
2-5/7
2-5/7
E coli
(0-6% in travellers)
Varies
(usually
1-5/7)
Dayswks
Many raw foods
Vibrio
parahaemolyticus
Yersinia
enterocolitica
12-24hrs
1-7/7
Shellfish
Mod severity gastro
3-7/7
1-21/7
Pork and
chicken
Bloods and pus in stool, severe AP
(may mimic appendicitis)
May cause reactive arthritis, erythema
nodosum, scarlatiform rash, GN,
conjunctivitis, hepatic/splenic abscess,
meningitis, osteomyelitis
Risk of bacteriaemia and metastatic
infection if immunosupp
Rapid deterioration with fever, hypoT,
V+D, haemorrhagic bullous rash 
necrotic ulcers
If immunocomp /
systemically unwell
Cotrimoxazole /
ciprofloxacin
Vomiting in children, diarrhoea in
adults
No
Gastro
No
Can cause bloody / mucusy
diarrhoea, systemic illness
Bloody stools without WBC
Profuse watery diarrhoea
Metronidazole +
iodoquinol
Vibrio vulnificus
Dysentry: Bloody mucusy stools and
tenesmus, systemic illness
Seizures, perf, HUS, Reiter’s
syndrome, fulminant toxic
encephalopathy
YES NEEDS ABX: As
public health measure
Can cause bloody diarrhoea, systemic
illness; can cause severe AP with little
diarrhea
Can cause reactive arthritis, GBS,
seizures, Reiter’s syndrome, neonatal
sepsis
Bloody diarrhoea and severe AP,
systemic illness
If severe / prolonged /
food-handler
Erythromycin /
norfloxacin
Norfloxacin if severe
IV ceftriaxone if <3/12
Debatable
Norfloxacin / cotrimoxazole / amox if
severe
Broad spectrum ABx
Viral
12-48hrs
12-60hrs
24-72hrs
Up to
1/52
Shellfish;
maybe infected
food handler
Food-handler /
water
Entamoeba
histiolytica
2-4/52
Wks –
mths
Food handler /
water
Cryptosporidium
1-12/7
2-21/7
Giardia lamblia
1-3/52
>1/52
diarrhoea
Food handler /
water
Food-handler /
water
History of rural
hiking;
contaminated
drinking water
Norovirus
(most common viral
cause)
Rotavirus
(most common cause
in children)
(0-36% in travellers)
Parasitic
Mild; flatulence, sulphurous belching,
bloating, abdo cramps; trophozoites
and cysts in stool
Pale, foul, greasy poo for >1/52
If severe /
immunocompromised
YES NEEDS ABX:
Metronidazole 2g
(child: 30mg/kg) OD
3/7
Pathology Invasive  cell damage and incr secretion
1) Decreased intestinal absorption – healthy SI absorbs 75% of fluid, LI absorbs 90%;
usually <100ml/day lost in stool; fluids absorbed passively with Na and actively with Glu;
Large vol suggests SI pathology, small vol suggests LI
a. Enterotoxins: block Na absorption, stimulate Na secretion  net loss of
fluid. Don’t affect Glu absorption, therefore add Glu to rehydration fluid
b. Inflammation / ischaemia – affect villi responsible for absorption
2) Increased osmotic load
a. Draws fluid into lumen
b. Will be associated with certain foods
3) Increased intestinal secretion
a. Unopposed crypt secretion – unaffected by inflammation
b. Persists with fasting
4) Abnormal intestinal motility
a. Occurs in IBS, short gut syndrome
RF’s: achlorhydria, bowel stasis, immunodef, recent ABx
Traveller’s Diarrhoea – usually don’t need ABx as usually self-limiting; treat with
norfloxacin 800mg (20mg/kg in child) PO single dose, or azithromycin 1g (child 20mg/kg)
PO single dose
Usually due to consumption of contaminated food and drink; educate about boiling water
etc…
Bacteria (80%)
Protozoa
Viral
E coli (Mexico, S America)
Salmonella (S Asia)
Campylobacter (S Asia)
Shigella (S Asia)
Giardia
Cryptosporidium
Entamoeba histolytica
Rotavirus, norovirus
Immunocompromised causes: cryptosporidium, microsporidium, isospora, CMV
Reiter syndrome: arthritis + conjunctivitis + urethritis/cervicitis = Salmonella, Shigella,
Campylobacter, Yersinia
Investigations
Stool Microscopy and culture – look for bacteria; low yield; indicated if child, toxic,
dehydrated, illness >3/7, blood/pus in stool, immunocomp
Cysts, ova, parasites – if traveler, >7/7 illness; may need multiple samples, as
again low yeild
Wright stain for fecal leucocytes – if +ive, more chance of invasive pathogen
Analysis for C. diff toxin – if recent ABx or hospitalisation
Electron microscopy, PCR, ELISA or latex agglutination to look for virus or C
diff toxins; may need multiple samples
Colonscopy: yellow plaques in C diff pseudomembranous colitis, usually in R colon; not
routinely required to make diagnosis
AXR If recent surgery
Drug levels, TFT’s
Non-infectious causes of diarrhoea: IBS, mesenteric ischaemia, thyroid storm, toxins (esp.
cholinergic), adrenal insufficiency, drugs (eg. erythromycin, laxatives, antacids, oral contrast,
lactulose, sorbitol, NSAIDs), GI bleed, acute radiation syndrome
If fecal evidence on inflammation and rule out Shigella, Salmonella, Campylobacter, C diff
and Entamoeba histolytica – then need to consider IBD
Trt
Mild
Mod
Drink 30-50ml/kg over 4 hrs
Drink 100ml/kg over 4 hrs
Avoid chewing gum, raw fruit; avoid sugary drinks (hyper-osmolar and no electrolytes 
incr fluid losses); avoid caffeine (incr cAMP  worsened diarrhea); avoid milk (transiently
lactose intolerant)
Attempt early solid food intake
Educate about food hygiene. Give sick note if work in health care / with food.
Cipro 500mg BD for 1/52 has been shown to shorten duration of infectious diarrhea 2Y to
bacteria
Hepatitis
Acute = self limited liver inj <6/12
Chronic = diagnosed on pathological criteria, >6/12
Incubation  pre-icteric  icteric  convalescent
ALT > AST (AST > ALT in cirrhosis); ALP normal or mild incr
A
Incubation /
Transmission
2-6/52
Fecal-oral
(contaminated
food and
water,
overseas
travel)
Rarely
parenteral
Reportable
disease
B
2/12
Parenteral
15% risk of
transmission
with sex
2-30% risk
seroconversio
n in needlestick
Acute infection
Fulminant / Carrier / Chronic
Prodrome for 1/52
 mild-mod jaundice, N+V+AP, tender hepatoM, dark
urine, clay coloured stools
 recovery over 1/12
Extrahepatic: vasculitis, ARF, pancreatitis, transverse
myelitis, seizures, aplastic anaemia
Infectious: from 2/52 before jaundice  1/52 after onset
jaundice
20% get relapse; >80% children asymptomatic
Serum Markers
Treatment
IgM-anti HAV = acute
infection; detectable 1st at
onset of Sx, 3/52 postexposure; remains for 36/12
Supportive
IgG-anti HAV = past
infection and immunity;
peaks 3/52 after IgM
Hep B than Hep A
HAV RNA = in
stool/plasma for most of
asymptomatic period;
disappears soon after onset
of Sx
Current acute infection:
HBsAg
HBeAg
IgM-anti HBcAg
Hep B DNA
HBsAg = acute, detectable 1st in preicteric phase; may
have normalized if late presentation; carrier if present on
2 occasions >6/12 apart
IgM-anti HBcAg = acute; high infectivity
HBeAg = acute and phase 2 chronic (usually decreases
in 3-4/52); high infectivity; marker of viral replication
Co-infection:
HBsAg
HBeAg
IgM-anti HBcAg
Hep B DNA
Anti-D virus
Fulminant: <1%
Chronic: No
Carrier: No
Acute = HBsAg and HBeAg, IgM-anti HBcAg
Symptomatic acute infection in 30%; Arthritis, fever,
skin eruption in preicteric phase; most common hepatitis
cause of ALF; mortality higher in ALF caused by
Give inactivated vaccine if
contact with case, within
2/52 exposure (nearly
100% effective)
Give NPIG if <1yr,
immunocomp, CLF, CI to
vaccine (80-90% effective)
Supportive
Trt if infected and
abnormal LFT’s or high
HBV DNA levels (likely
in acute, phase 2 + 4
chronic) – entecavir,
lamivudine, tenofovir
etc…
Vaccine available
(HBsAg)
Fulminant: 0.1-0.5% (mortality rate 80%)
Chronic: 5-10% (1-3% healthy adults, 5-10%
immunocomp, 90% neonates) = HBsAg >6/12, IgG-anti
HBcAg, maybe HBeAg, anti-HBeAg
 cirrhosis and hepatocellular Ca; shortens life span in
45% men, 15% women
Phase 1: immune tolerance; 20-40yrs; normal ALT;
high levels viral replication; no trt
Phase 2: immune clearance with immune response;
symptomatic in 30%; hepatitis, incr ALT  fibrosis with
repeated episodes; cirrhosis in 30-40%
Phase 3: immune control  immune response
suppresses replication  decr inflamm, ALT normalises;
5-10%/yr phase 2 become phase 3; assoc with HBeAg
seroconversion (anti-HBeAg develops, decr HBeAg);
hepatitis stops; may reactivate at any time
Phase 4: immune escape; recurrence of hepatitis,
fibrosis; virus mutates and stops making HBeAg; incr
ALT; 8-10%/yr develop cirrhosis
Chronic active Hep B:
HBsAg
HBeAg
IgG-anti ABcAg
Hep B DNA
If non-immune exposed,
give anti-HBsAg within
1/52 (75% effective)
Previous resolved Hep B:
Anti HBsAg
Anti-HBeAg
IgG-anti ABcAg
Carrier:
IgM-anti HBcAg
Vaccinated:
Anti-HBsAg
IgG-anti ABcAg = chronic, previous infection
Anti-HBeAg = phase 3 chronic; low infectivity;
indicates viral replication as ceased
HBV DNA: high infectivity, used for monitoring
response to trt
Carrier: 1-10% = HBsAg
Accounts for 90% chronic infections
C
2/12
D
Parenteral
80%
prevalence in
IVDU
15% rate of
transmission
with sex (rare)
10% unknown
source
<2%
seroconvert
with
needlestick
4-7/52
Parenteral
Sexual rare
Usually IVDU
Only occurs in
patients with
acute/chronic
HBV
5% HBV
IgG-anti HBsAg = immunity and recovery
Acute = HCV RNA: Pre-icteric non-specific; usually
asymptomatic (Sx in 15-20%)  icteric phase for 12/52; Extrahepatic Sx in 75%: arthralgia, paraesthesia,
myalgia, pruritis, sicca
 spontaneous resolution in 30-50%
Fulminant: Rare
HCV RNA = acute,
detectable 1st within 1-2/52
exposure
IgG-anti HCV = chronic;
+ive by 3/12 usually
Chronic = IgG-anti HCV: 75-85% adults; 55% children
25% develop cirrhosis over 20-30yrs; 20% cirrhotics
develop hepatocellular Ca
Supportive
Interferon if persistently
high LFT’s (effective in
1/3); peginterferon +
ribavarin (effective in
50%)
No vaccine / postexposure prophylaxis
available
Carrier: 0.2-1%
Acute = HDV RNA, Ig-anti HDV: in 2-20%
Co-infection – hepatitis with resolution in 80-95%
Fulminant: 2-20% if super-infection
Chronic = Ig-anti HDV: 5-10% if co-infection; 80% if
super-infection
Carrier: Low
1-10% IVDU and haemophiliacs are carriers
HDV RNA = acute
Co-infection =
IgM-anti HDAg
+ IgM antiHBcAg
Super-infection =
IgM-anti HDV
+ HBsAg
IgM/G-anti HDV = acute /
chronic
Supportive; interferon may
help
Otherwise as per HBV
E
carriers have
HDV
2-8/52
Fecal-oral,
water-bourne
Acute = HEV Ag, IgM-anti HEV: Self-limited; 1-3%
overall fatality; 5-25% mortality in pregnancy
Fulminant: 20% if pregnant
Chronic: No
Carrier: No
Virus
Acute infection
Chronic infection
A
HAV RNA
 IgM-anti HAV
HBsAg
 IgM-anti HBcAg, HBeAg
B
C
HCV RNA
D
HDV RNA
 IgM-anti HDV
HEVAg = acute
IgM-anti HEV = acute
Supportive
IgG-anti HEV = immunity
Carrier
No
Immunity and
recovery
IgG-anti HAV
5-10%
IgG-anti HBsAg
1-10%
IgG-anti ABcAg, HBeAg (phase 2)
 Anti-HBeAg (phase 3)
75-85%
No
HBsAg
0.2-1%
IgG-anti HCV
5-10%
Low
IgG-anti HDV
Co-infection =
IgM-anti HDAg + IgM antiHBcAg
E
Super-infection =
IgM-anti HDV + HBsAg
HEVAg
 IgM-anti HEV
No
IgG-anti HEV
No
Other causes: ETOH; non-alcoholic steatohepatitis (10-50% develop cirrhosis); drug induced (necroinflammatory eg. Paracetamol; cholestatic eg. Chlorpromazine); autoimmune
Hepatorenal Syndrome
Development of ARF in patient with normal kidneys in presence of preexisting A or CLF;
cause unknown
Type I
More serious; progressive oliguria; Cr x2 in 2/52; survival without
medical trt <1/12
Type II
Gradual impairment of renal function
Toxic Megacolon
Defintion: non-obstructive colonic dilation with fever + abdo distension + severe AP + shock;
distension can be segmental / total
Pathophysiology: NM tone decr 2Y to transmural inflammation; abnormal if >6cm;
transverse colon most commonly affected; occurs in IBD, but also in Crohn’s (also in
ischaemic bowel, pseudomembranous colitis, radiation colitis, infectious colitis, Hirschsprung
disease
RF’s: precipitated by hypomotility agents (eg. Loperamide), Ba enema, hypoK, opiates,
anticholinergics, pregnancy, enema, recent colonscopy
Sx: severely ill, fever, profuse diarrhea, hypoV, incr HR, abdo distension, severe pain,
tenderness and peritonitis, N+V, rectal bleeding may occur; Sx may be masked by steroids
Complications: perforation, circulatory collapse, septicaemia
Investigation: Bloods (FBC, U+E, glu, lipase, LFTs, cultures, ABG, ESR, CRP); XR (loss of
haustra, thumb printing, air filled dilated segments of colon >6cm); CXR (for perf); ECG;
scope (carries risk of perf); CT (for complications like abscess and perf); effectiveness of
scope screening controversial
Mng: admit if severe disease, suspected complications; response assessed by serial XR
1. IVF: as indicated
2. Analgesia
3. NG, NBM
4. Sulfasalazine: 1-4g/day; for mild-mod
Mesalazine: better tolerated, equally effective, can be given PR
Antibiotics: for severe disease; ampicillin / gent + clindamycin / metronidazole
5. Steroids: pred 25-50mg; hydrocort 100mg Q6h; enemas / IV / PO
6. ImmunoS: if refractory; azathioprine, ciclosporin (may avert need for OT),
tacrolimus, infliximab
7. Total colectomy: if drug resistant (ie. No response in 24-48hrs)
Prognosis: >30% mortality; 15yrs disease  12% risk of Ca, 20yrs  23%, 25yrs  42%,
risk greatest with pancolitis
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