Case 11 Flashcards
1
Q
What are the consequences of diarrhoea ?
A
Electrolyte imbalances and dehydration
2
Q
A px has a stool culture which comes back negative, what does this mean ?
A
Problem does not have a bacterial cause
3
Q
What are the 3 main causes of low Hb?
A
Blood loss , Fe deficiency in diet , Fe absorption failure
4
Q
What deficiencies are shown in micro and macrocytic anaemia ?
A
Micro = Fe def (MCV falls) Macro = b12/folate def
5
Q
What are the layers of the GI tract from superficial to deep ? ( 10)
A
CT layer (serosa) Longitudinal muscle Myenteric plexus Circular muscle Submucosal plexus Submucosa Muscularis mucosa Lamina propria Epithelium Lumen
6
Q
Where are Brunner’s glands found and what is their function ?
A
Located in the submucosa of the duodenum
The secrete HCO3
7
Q
Where are intestinal glands and goblet cells located relative to the duodenal villi ?
A
Goblet cells are on the outer surface just inside of the enterocytes
Intestinal glands are in the gaps between the villi
8
Q
How is the jejunum structured differently to the duodenum ?
A
Highly folded or max absorption (SA^)
Plica circulares is the name for one group of villi
No Brunner’s glands (so no HCO3)
9
Q
How would you differentiate between the ileum and the rest of the SI under a microscope ?
A
The ileum contains Peyer’s patches, found between muscalris and sub mucosa. They’re important for immune function through monitoring of bacteria, prevent pathogenic growth
10
Q
How would a blood capillary appear on a histological section ?
A
Small oval/circle filled with lots of red dots
11
Q
Where are B12, folate and Iron absorbed in the body ?
A
Dude I just feel ill bro
Duodenum = Iron
Jejunum = Folate
Ileum = B12
12
Q
Along with Fe, what other structures are absorbed in the duodenum ?
A
Ca and monosaccharides
13
Q
How are microcytic anaemias broken down ?
A
Absorption or malnutrition problems. Think of px’s age e.g. doubt 40 yo man is anorexic
14
Q
What is a tTG test used for and what other test would you have to issue with it and why?
A
IgA tissue transglutaminase (tTG) is used to indicate coeliac. A high result = +ve
You also have to run a total immunoglobulin A test to check for a deficiency, because this would give false -ve for coeliac (if IgA was low)
15
Q
What is scalloping ?
A
Appearance under an endoscopy is inflammed, swollen with worse definition. The bumping looks similar to cobble stones.
16
Q
What is the significance of inflammation in the villi/mucosa ? Give an example enzyme in the brush border …
A
Inflammatory cells block off villi/mucosa so nutrients don’t come into contact with brush border -> enzyme digestion decreases
Lactase breaks down lactose in BB
17
Q
What is the trigger of bile ?
A
Fat in the duodenum causes CCK release from I cells.
18
Q
What is the consequence on digestion of inflammation ?
A
No CCK release because I cells inflamed
Brunner’s glands can’t release HCO3 to neutralise the acidic chyme
Long chain fatty acids can’t be endocytose by enterocytes
19
Q
How is diarrhoea defined ?
A
Passage of 3 or more loose or liquid stools per day (or more frequent than is normal for the px). Roughly 200g
20
Q
What are the 4 main types of diarrhoea ?
A
Osmotic , Inflammatory , Secretory and Mobility
21
Q
What is osmotic diarrhoea ?
A
non absorbable substance means H2O moves into lumen. Retention of H2O in bowel. Often due to lactate deficiency or use of sugar substitutes (slow absorption but cause rapid motility)
22
Q
What type of diarrhoea; water not absorbed through walls so remains in stool. Mainly colon causes abdominal pain, fever and bloody diarrhoea ?
A
Inflammatory pathogens e.g.; shigella, salmonella, campylobacter, e.coli and c.diff
IBD shows inflammatory
23
Q
What are the secretions in secretary diarrhoea ?
A
Mucosal lining secretes Cl and HCO3 into fluid. Electrolyte absorption affected, H2O released into SI. Common during infection or certain drug use
24
Q
What is the difference between acute (watery and blood) and persistent diarrhoea ?
A
Acute, lasts several days and includes cholera
Bloody = dysentery
Persistent, 14+ days
25
What type of diarrhoea ; watery diarrhoea expelled violently with gas ? Common cause ?
Explosive , commonly due to bacterial infections
26
What is steatorrhea ?
Less fat absorbed in the intestines so more present in stools. Causes; diet, kidney disease, CD, coeliac, gallstones
27
What is the key ingredient in chillies that causes the burning sensation and sometimes burning diarrhoea ?
Capsiacin
28
What is lassitude ?
Lack of energy without exertion
29
Where is B12 absorbed ?
Terminal ileum
30
What condition is referred to as transmural ?
Crohn's disease, affects whole wall
31
What is cobblestoning ?
Ulcers form in the terminal ileum that reduce the SA of villi and appear hard and bumpy like cobblestones
32
What is pyloric gland metaplasia ?
Pits in the ileum heal poorly and lead to fall in SA and efficiency
33
How would you tell if there is infection on a histological section of the ileum ?
Shows Casciation, can be seen as 'cheese blocks' under section.
34
What does a high fat content show in a stool sample ?
May be an indicator or steatorrhea of lactose intolerance
35
What is the first course of tx when a px is in shock ?
ABC and calm them down.
| Rehydrate in order to active ADH to ^ retention. Can give hydrocortisone (steroid) or prednisone to help
36
What are the key indicators of dehydration ?
Creatinine and urea ^
37
What is Chaggers disease and how would you identify it ? Would can it cause ?
Large bowel enlargement due to SM dysfunction not maintaining tone. Shows 'thumb printing' on Xray. Can lead to toxic megacolon, CVD.
38
What are pseudopolyps and what can they cause ?
Projecting masses of scar tissue that project form granulation tissue during healing phase of repetitive cycles of ulceration. Rest of mucosa becomes inflamed/ulcerated -> destroyed
39
What does a decrease in albumin show ?
Fluid imbalance , possibly from not eating or drinking properly
40
What is the significance of diarrhoea and a job involving food handling ?
Have to wait for 2 days for sx/illness to pass before returning to work.
41
When would you report infectious diarrhoea ?
Every time no matter the occupation.
42
What do FBC and CRP levels indicate ?
full blood count shows inflammatory markers
| C reactive protein shows infection+inflammation produced by liver
43
How would you obtain a stool culture ?
Obtain sample. Culture specimen on selective blood agar plate with abx that inhibit most faecal flora.
Incubated in warm temps with no O2
Look under microscope and identify organism
44
What are the microbiological characteristics of Campylobacter ?
Red rod like worms. Gram -ve , helical. Possible cause of IBD
45
What are the two most common bacterial causes of gastroenteritis ?
Salmonella and Campylobacter
46
What are the bacterial causes of gastroenteritis that arise from poor hygiene and food poisoning ?
E. coli and Staphylococcus
47
What is diverticulosis ?
Bits of inner mucosa push through deeper layers of gut forming pouches. More common with age from ^ wear and tear.
48
What are the 5 complications of diverticulitis ?
```
Inflammation/infection
Diverticular abscess
Strictures, cause LB obstruction
Fistula -> pneumaturia and faecal leakage obstruction
Perforation or bleeding
```
49
What are the risk fx for C.diff? (6)
```
multiple/lengthy abx (most common)
long stay in hospital
frailty and immunosuppression
Exposure to PPIs
Age >65
Comorbitides eg. renal failure
```
50
What are pseudomembranes ?
Appear to be raised bits of mucosa under endoscope, countless bits of yellow mold bumps.
51
What is pseudomembranous colitis ?
Secondary to C.diff infection. Mucopurulent exudate erupts out of crypts. Under biopsy each one looks like a mushroom cloud.
52
What is the issue with superficial crypts during pseudomembranous colitis ?
They cause patchy necrosis that leads to dilation of the membrane. Leads to end stage of disease, entire crypts necrotic, resembles ischemic colitis.
53
How would you tx pseudomembranous colitis ? (3)
Re establish fluid balance (oral or IV)
Stop causative abx
Give vancomycin and metronidazole (if serious)
54
What tx would you use to treat recurrent C diff ?
FMT, faecal microbiota therapy (stool transplant).
55
What are the two layers that enclose the abdominal cavity ?
Greater and lesser omentum
56
What is the name for the double layers of peritoneum and what is their function ?
Mesentery
| Carry blood vessels and lymphatics supplying the organs
57
List the retroperitoneal organs ...
Suprarenal glands, Aorta/IVC, Duodenum (2-4 parts), Pancreas , Ureters , Colon ( ^ + descending) , Kidneys , Eosophagus , Rectum
58
Peritoneal fluid usually absorbed by pores in peritoneal membrane. What is the term for when fluid ^ ?
Ascites, often blockage occurs due to metastatic tumours.
59
Which two organs are connected by the lesser omentum?
Liver and stomach
60
What is the name of the hole that connects the two sacs ?
Epiploic foramen
61
What is the name of the procedure used to drain the greater sac and what is the process ?
Paracentesis , needle into the anterolateral abdominal wall.
62
Where would an accumulation of fluid in the infra colic compartment track to in an erect individual and why?
Pouch of Douglas , lowest point so gravity flow
63
What is Morrison's patch ?
Space between right kidney and liver, allows fluid to move from infra to supra colic compartment via the paracolic glottis.
64
What is air under the diaphragm referred to as ?
Pneumoperitoneum , black on X-ray due to less dense that air.
65
Where does the primordial foregut meet the midgut ?
2nd region of the duodenum and the ampulla of Vater
66
What is the ligament that attaches the end of the duodenum to the post abdominal wall ?
Ligament of Trietz , attaches the duodenal flexure. Landmark for surgery because it remains constant.
67
What are the normal diameters of the SI, LI and caecum?
SI = 3cm , LI = 6 , Caecum = 9cm
68
What is the name of the junction between the ileum and LI and where is it located ?
Ileocecal valve
| In the RLQ
69
What is intussusception ?
Intestines slide into adjacent regions causing blockage and potential vascular obstruction.
70
When the appendix becomes inflamed its lumen can be obstructed leading to distention and swelling. Where is the pain felt ?
Umbilical region.
71
How is pain felt if the structures are innervated by the autonomic NS ?
generalised dull aching pain
72
After appendix inflammation the parietal peritoneum becomes involved. How does the pain change?
Innervated by somatic, segmental nerves so pain is severe highly localised and sharp. Pain is felt in the Right Iliac fossa.
73
Name same conditions where appendicitis may be in a different location ?
Pregnancy, growing uterus pushes appendix ^
Citus inverts, R/L axis swap so pain in LIF
Some have appendix behind colon
74
What is the name given to the surface position for the appendicular orifice used in surgical excision of the appendix ?
McBurney's point
75
Removal of the appendix would require ligation of which artery running in the mesoappendix ? Where does it arise?
The appendicular artery. Arises from the ileocolic branch of the SMA
76
Which parts of the colon are intraperitoneal ?
distal 1/3 transverse and sigmoid
77
What 3 features of the LI can be used to distinguish it from the SI in surgery ?
Haustra (small pouch sac formation) , Teni Coli (longitudinal ribbons along length) , size/diameter
78
What is a haemorrhoid ? How are the felt during a PR exam?
Enlargment of the veins due to straining (piles). On the surface of anus/rectum as little bumps.
79
What is the difference between internal and external haemorrhoids ?
Internal, originate from sup rectal veins, are painless due to have no nerve supply (endoderm)
External, from the inf rectal veins, are acutely painful.
80
Which blood vessel acts as a landmark to distinguish between two types of inguinal hernia ?
Inferior epigastric vessels; indirect - lateral and direct - medial
81
What are the two types of inguinal hernia ?
Direct, bowel enters abdominal cavity 'directly' through weakness in the post wall. ^ with age, due to ^ intra abdominal pressure and wall laxity.
Indirect, bowels enters inguinal canal through deep inguinal ring due to failure of closure of the process vaginalis - deemed congenital in origin.
82
For direct inguinal hernias, what is the weakness in the post wall referred to as ?
Hesselbach's triangle
83
Where does the sympathetic and parasympathetic innervation arise from in the gastrointestinal system ?
Sympa - sympathetic trunk in the thorax
| Para - from the vagus and pelvic splanchnic nerves
84
What are the spinal levels of the fore, mid, and hindgut and so what are there areas of referred pain ?
```
Fore = T5-T9 -> anywhere above umbilicus
Mid = T10/11 -> umbilicus
Hind = L1/2 -> hips and ASIS
```
85
Which CN provides para innervation of the gut up until the splenic flexure of transverse colon ?
Vagus , 'wandering' in latin. It's the longest
86
What is Hirschprung's disease and what are the signs?
Congentical megacolon. Ganglia absent from myenteric plexus causes constipation and reduced gut motility
87
What are the 3 branches of the aorta that supply the gut and their spinal levels ?
Coeliac trunk (T12) , SMA (L1/2), IMA (L3)
88
What are the main beneficial properties of intestinal bacteria ? (3)
Enterohepatic circualtion; breakdown of food, drugs aid absorption
Nutrition; metabolise vits eg. B7 9 12, K
Infection, normal flora prevent growth of endogenous and limit infection from exogenous.
89
How might a poor gut lead to clotting disorders ?
Poor gut nutrition means Vit K isn't metabolised so specific fx aren't made.
90
What are the properties of C diff bacteria and how is it spread?
Gram +ve rod, mostly LB disease, destroys normal gut flora. Spread faecal orally due to poor hygiene.
91
Why are C diff recurrent infections common ?
Spores are resistant to chemicals and heat so won't dry out. They are then able to replicate in the gut and cause infection.
92
How would you manage a C diff infection on an individual and multiple scale ?
Fluid balance, anti C diff abx , surgery.
| Isolate cohort / environmental cleaning.
93
What abx would you use for a C diff infection ?
Coamoxiclav (combo of amoxicillin and Clavulanic acid) used as broad spectrum abx.
Then narrow to target gut; Metronidazole for moderate and Vancomycin for severe (often now used 1st line)
94
What is the advantage of a FMT during C diff infection?
Faecal microbiota transplant
| px restores normal biota and limits C diff migration sites.
95
What bacteria are curved motile gram -ve rods , that are the commonest cause of IID ?
Campylobacter , Infectious intestinal disease
96
How long do sx of campylobacter last and how are they resolved ?
normally 2-7 days , usually self limiting but persistent / recurrent if px is immunocompromised
97
How do you ^ prevention of campylobacter infections ?
better kitchen hygiene and isolation of sx patients.
98
Salmonella is a grame -ve motile rod. What 2 major problems does it cause via which subtypes ?
Food poisoning , S enteritidis
| Thypoid (enteric fever) , S typhi and S parathyphi
99
How long does a salmonella infection last ?
Ilness normally 48-96 hrs. Can take up to 9 weeks, asymptomatic shedding is a major problem
100
What tx can be used in Salmonella becomes serious ? (Wouldn't use meds if mild)
Quinolones, macrolides, cephalosporins
101
What is enteric fever ?
Salmonella cause febrile illness with cough and constipation common.
102
What condition would you treat a px with fluoroquinolone?
Enteric fever.
| Can also use Ceftriaxone, azithromycin
103
What are the 4 types of E coli ?
Enterotoxigenic , Verocytotoxin , enteroinvasive, Enteropathogenic
104
Where does VTEC act and what can it cause ?
Verocytotoxin (E coli)
direct attachment to terminal ileum and colon, shows widespread outbreaks eg. in food.
Can cause HUS (haemolytic uremic syndrome - RBC breakdown)
105
How do you treat cholera ?
Aggressively rehydrate initially
| Vaccines available for travellers to ^ risk areas.
106
How is shigella spread ?
non motile Gram -ve rods. small infectious dose spread through faecal oral spread in poor hygiene.
107
What is the norovirus ?
non enveloped ssRNA virus that affects SB. Can last in air for hours.
108
How long is the incubation period for norovirus and what sx are seen during this time?
24-48 hrs , fever vomit diarrhoea.
109
What is the commenest cause of infant diarrhoea that affects the small bowel with types A+B effecting humans ?
Rotavirus
110
How would you detect and manage the rotavirus ?
Detection using ELISA test
| Management; isolation using careful transport and then clean the environment
111
What is the two stage life cycle of intestinal protozoa giardia lamblia ?
flagellate trophozoite in host duodenum attaches to epithelium and reproduces by binary fission. Cyst then passed to stool where it's highly infectious
112
How would you diagnose Giardia ?
Stool microscopy, iodine stain to reveal cysts. Ag detection assays used to test px post outbreak/tx
113
What is the 1st line tx for Giardia ?
Metronidazole , Tinidazol can also be used.
114
Cryptosporidium; what is it, where does it multiply, what does it cause ?
Intestinal sporozoa that multiplies in SI. 1-5 oocytes cause infection. Major diarrhoea cause in immunocompromised
115
What is Cryptosporidium resistant to and how is it transferred between hosts ?
Resistant to Chlorine and Disinfectant
| Transferred via H2O, mainly mammal hosts
116
What are the sx of Cryptosporidium and what are the major complications that can develop ?
Diarrhoea with abdominal cramps and weight loss, may develop cholangitis and cholecystitis
117
What is the special method through which Cryptosporidium is diagnosed ?
```
Oocytes may be seen in stool microscopy.
Modified ZN (Ziehl-Neelson) stain which is acid fast staining that causes bacilli to be pink
Has to be used on structures which are resistant to Gram staining
```
118
What key investigations would show an ^ as a result of malabsorption ?
FBC , WCC (inflam) and anaemia
119
What are the +/- of biopsy ?
May be useful in C diff for diagnosis and to exclude IBD
| Risk of perforation ^ so avoid where possible
120
How would these specimens look on an agar plate; campylobacter , E coli , Salmonella , Vibrio cholerae ?
Campylobacter; black with white hashtag
E coli ; Pink with white spots
Salmonella ; red with white spots
Vibrio cholerae ; grey with fluorescent green lines
121
What are the main causes of malnutrition ? (5)
Anorexia (disease,anxiety,depression) , difficulty in food to mouth/chewing , oral intake contra, enforced fasting (religious) , sedations comatose
122
What occurs in the period after starvation (24 weeks starved then 12 not) ?
Rapid ^, fat ^ to higher than previous value. Depression ^ during fasting period.
123
What is marasmus ?
Malnourishment of a child causing them to be significantly under projected weight percentiles. Normally metabolically stable to chronic fall in food intake
124
What effect does malnourishment/anorexia have on these systems; wound response, gut, CV, Resp, CV, Res, Renal, Liver, Pancreatic, Intestines ?
Wound response; collagen made of protein so healing takes longer and is worse
Gut; integrity falls as tight junctions break -> leaky
CV; ventricular mass and CO falls -> Brady/hypertension
Resp; ventilatory drive/cell mediated immunity falls. Cough P down so ^ chest infections. need ventilatory support for longer
Renal; gradual loss of function. less able to concentrate urine in renal medulla so lower conc grad -> polyuria
Liver; nothing until near death. glycogen and fat stores used up.
Pancreatic; atrophies -> endo/exocrine function falls
125
What is the effect on the intestines during malnourishment ?
presence of nutrients in the gut needed for mucosal growth/function through activation of trophic GI hormones. ^blood flow (activation of ANS). malnutrition -> less absorption, less motility, immune impairment
126
How can a loss of weight affect absorption?
Villi height falls, atrophy and thinning of mucosa so SA down. Less brush border enzyme activity -> steatorrhea/diarrhoea ^.
127
What is sarcopenia ?
loss of body muscle but retention of fat, appear obese but lean mass is normal
128
What is Kwashiorkor malnutrition ?
Fluid retention due to lack of protein in the diet. Shows poor response to infection, loss of electrolytes. ^urinary nitrates.
129
What are the fat soluble vitamins ?
A, caretonoids for vision, antioxidants
D, made using sunlight. def -> rickets, depression, schizophrenia, asthma. Muscle weakness (OA)
E, antioxidants. Role in stroke prevention/cancer/HD
K, attributes to blood clotting fx. def -> internal bleeding
130
What is Beri Beri syndrome ?
B1 def. neck veins enlarged, fluid in lungs, ^ HR, swelling in legs. Coordination problems, reflexes slow.
131
Name some water soluble vitamins ?
B1 (thiamine) carb metabolism
B2 (riboflavine) energy metabolism. def > angular colitis/stomatitis/glossitis.
B6 (pyridoxine) , B7 (biotin) def > alopecia, B12 (cobalamin)
132
What is the WAASP assessment for nutritional tx?
Weight, appetite, ability to eat, stress, pressure (sores/wounds)
133
What are the example screening questions during a nutritional assessment ?
Have you lost weight recently?
Has your appetite lessened ?
Are your clothes or dentures loser than normal ?
134
What is the estimated requirements of a 46 yo women post op in terms of calories and protein ?
Calories - 1668
| Protein - 74 g
135
What is the cascade process that causes ^ P53 and what is P53 ?
APC > K-ras > SMAD4 > P53
| Gene that codes for a protein that regulates the cell cycle so acts as a tumour suppressor
136
What are the common presentations of bowel cancer ? (3)
Anaemia bleeds on R side > tiredness/SOB
Change in bowel habits, >3/day and/or up at night to poo
Obstruction, vomit pain abdo distention and constipation
137
What is the difference between proto-oncogenes and oncogenes ?
Protooncogenes are the normal form which help regulate cell growth and proliferation
Oncogenes, activated so cell activity ^
138
What is the consequence of a single or double gene mutation in TS genes ?
Tumour suppressor
1 is ok because the other still regulates/'acts as breaks'
2 means there's no regulation > rapid proliferation.
139
What are the risk fx for colorectal cancer ? (
Famalial, diet (lack of fibre, ^ red meat, ^ processed food)
140
What is SNP ?
Single nucleotide polymorphism , single base changes that can cause variety of effects when totalled
141
What are the properties of cancer cells that allow them to rapidly proliferate ? (3)
Create own vascular supply (central tumour cells would self deprive themselves of O2)
Metastasis , can help to avoid the immune response
Insensitive to growth inhibitory signals. Evasion of apoptosis
142
How is FAP normally regulated ?
Familial adenomatous polyposis
APC gene on Ch5 regulated by b catenin
APC binds to GSK3b > destruction complex > breakdown of b catenin to keep levels low.
143
How does FAP develop when b catenin isn't broken down?
B catenin moves into cell > activates oncogene > proliferation > apoptosis > uncontrolled growth
144
What are the extra intestinal manifestations of FAP ?
CHRPE (congenital hypertrophy of retinal pigment epithelium) - black spots on back of the eye
Desmoid tumour, growth of fibroblasts (produce collagen) . Benign but rapid growth so remove surgically.
145
Post op (for FAP) what is the tx plan for the px ?
^GI surveillance because risk of polyps and cysts in stomach and GI tract ^
146
How would you diagnose colorectal polyps ?
DNA extraction from WBC or lymphocyte. Tested in genetics diagnostic service. Abnormal stop codon in gene > mutation so not enough APC (for example) made
147
What is the difference between Ulcerative colitis and Crohn's disease ?
UC - diffuse mucosal inflammation limited to colon, normally rectum. May extend symmetrically to LI. Diagnose using an endoscope
Crohn's - Patchy transmural inflammation anywhere on GI tract. Typically non bleeding. SB involvement with rectum sparing.
148
What is the normal appearance of the colon and how does this differ to severe UC ?
Norm, shiny purple/pink and retains delicate reticulated vascular pattern
Severe, macro ulceration with mucopurelent exudate and spontaneous haemorrhage
149
What are the common sx of UC ?
bleeding (rectal can lead to anaemia), diarrhoea (not present in proctitis), urgency to poo, abdominal pain
150
What is proctitis ?
Rectal inflammation subset of UC. No diarrhoea, poo forms further round colon therefore just mucous and blood comes from the rectum.
151
What is an early radiological sign of toxic colitis ?
Gas accumulation over the colon. Luminal diameter is slightly smaller with scalloped margins from edema/spasm
152
What is the danger with toxic megacolon ? where is the dilation largest ?
Perforation or peritonitis.
| Dilation at max in the transverse colon because fluid collects in flaccid bowel when supine
153
In toxic megacolon how would you redistribute the gas and what effect would this cause ?
Rotate the px in supine , redistributes the gas and decompresses the colon.
154
What are perforations ?
complication of UC, subserosal dissection of luminal gas into the bowel wall.
155
What is the advantage of colonoscopy in decreasing colorectal cancer risk ? What is the first cancer sign?
Highlights bowel structure targets abnormal areas to avoid biopsy.
First sign = visual dysplasia
156
Name some extra intestinal manifestations related to IBD (4)
Aphthous stomatitis (mouth ulcers) , Orofacial granulmoatosis (OFC) lip swelling w/ fissures, inflam etc. , Episcleritis and uvetis (eyes) painful red eye light causes iris to contract pain due to inflam , Arthritis etc.
157
What is the most common extracolonic manifestation of colitis ?
Peripheral arthritis. Joint inflam similar to RA but affects large joints , no synovial destruction and is asymmetrical.
158
How would you differentiate between peripheral arthritis and RA ?
Peripheral arthritis is seronegative (-ve in blood test for rheumatoid fx)
159
What is the difference between Erythema nodosum and Pyoderma gangrenosum?
Erythema nodosum - bowel activity down > pale coloured skin with red spots. Seen in Crohn's self healing
Pyoderma gangrenosum - trauma lesions red area w purple edge on shins, hands etc. Seen in UC need tx
160
What conditions are associated with HLA-B27 on Ch6?
Central athropathy, ankylosing spondylitis (fibrosis/fusing of vertebrae) , spondylitis, sacroilitis
161
What is sclerosing cholangitis ?
Bile ducts becomes distorted, truncated and have segmental areas (narrowing/bleeding)
162
What major types can Crohn's disease develop into ?
Obstructive , fiscalisation and Ileitis
163
What is obstructive Crohn's disease ?
1st stricturing > inflam+fibromusclar proliferation, collagen deposition in intestinal walls > narrows lumen.
164
Px presents with post prandial cramps and vomiting. They have also noted weight loss recently. What is your diagnosis ?
Obstructive Crohn's. Food distention causes cramping most evident after meals. Vomiting is from high grade obstruction. Weight loss could be due to avoiding food.
165
What is the Fistulation that is seen in Crohn's disease ?
wall thickens, lumen narrows penetrative ulcers form. Culminates in sinus tracts + fistulae formation to adjacent structures.
166
What different sx would be experienced depending on the location of the fistulae ?
Enteroenteric ; may be asymptomatic
Enterovesical; recurrent UTIs , pneumaturia (gas in urine)
Retroperitoneal; psoas abscess (back, hip, thigh pain)
Enterocutaneous; (stomach contents leak into skin) drainage via scar
Perianal; pain swelling pus.
Rectovaginal
167
How would you tx a perianal or rectovaginal fistula ?
Perianal - anal suture 'seton' used to tie knot prevents fistula blockage
Rectovaginal - drainage
168
What is the cause of a perianal fistula ?
Crypts of morgagni in anus spread through internal sphincter muscle > intersphincteric, isorectal supralevator abscess etc.
169
Which condition shows; modularity, ulceration, narrowing and irregularity of the lumen. Overall transmural inflammation and lymphoid proliferation ?
Ileitis as a result of Crohn's , irregular intestinal loops form as lumen narrows and wall thickens with mesenteric hypertrophy.
170
What is the 'string sign' ?
Combination of transmural thickening with erratic spasms in the terminal ileum indication ileitis.
171
If a px presents with major perianal lesions with a history of IBD, what is the likely diagnosis and what can you rule out ?
Likely is Crohn's
| Never seen in UC
172
Px presents with fistulation into surrounding tissue and organs around the bowel in an asymmetrical pattern. What is your diagnosis ?
Crohn's
173
What are the differentials between IBD and IBS ? (5)
IBD +ve for; anaemia (platelets ^ albumin drop) , weight loss/fever , perianal disease, bloody stools , faecal WBC count.
174
What is the faecal calprotectin test ?
Test to rule out IBD. If a little +ve then useless because could still be both. If very +ve = IBD. If -ve then not IBD (IBS)
175
When are the peaks of onset for Crohn's and UC ?
Late adolescence/early adult has a peak for both. Crohn's has a 2nd peak in 60's/70's.
176
IBD has ^ too rapidly to just be a cause of genetics. What are the other possible causes and during which time period ?
Urbanised living ^ , industrialisation/pollution
| Influence occurs during childhood
177
How does an appendectomy affect UC and Crohn's ?
In young px (<20) prior to UC shows protective effect
After onset procedure shows no difference.
Crohn's shows no difference whatsoever
178
Name some drug tx that can be used for UC and Crohn's (4)
Mesalazine (anti inflam) works in UC
Corticosteroids used in both
Azathioprine (immunosuppressants) oral works in both
Anti TNF used in both, injected
179
What are anti TNF antibodies ? Give examples when they would be used...
Used instead of steroids normally. Monoclonal antibodies that target TNF bound to membrane, fast acting.
Infection' infliximab and Vedolizumab > lymph traffic inhibitor binds to interns on surface lymphocytes
180
What is Sulfasalzine ?
Cause of clinical toxicity, especially in px who are slow acetylators. Composed of aminosalicyclic acid (5-ASA) - an aspirin analogue - bound to a diazo bond.
181
How is sulfasalzine activated ?
Intestinal bacteria cleave the di-azo bond, releasing 5-ASA which causes drug toxicity.
182
How is Sulfasalzine absorbed and metabolised ?
30% upper GI/kidneys. Most absorbed by liver excreted in urine.
183
What is the drug tx ladder for UC ?
mild = Mesalazine . Severe = Anti TNF then corticosteroid. Maintenance of remission = Mesalazine and azathioprine / 6-mercaptopurine
184
What is the drug tx ladder for Crohn's ?
```
Mild = Budesonide (locally active corticosteroid) with dietary therapy and abx
Severe = Anti TNF > Corticosteroids
Maintenance = azithioprine and anti TNF
```
185
What is the link between Azathioprine and 6-mercaptopurine ?
Azathioprine is a pro drug quickly converted to 6-mercapotpurine via non enzymatic nucleophilic attack by sulfahydryl compounds (glutathione) present in RBC and other tissues
186
What abx can be used in tx of Crohn's ?
Metronidazole and Ciproflaxacin
187
What conditions might Methotrecate and Ciclosporin be used for and why ?
Methotrecate (Crohn's) and Ciclosporin (UC) are immunosuppressive drugs
188
What is the function of Vedolizumab ?
Used in infection, gut specific lymphocyte traffic inhibitor. Response to MAdCAM-1 allowing lymph straight past inflammatory site therefore preventing response.
189
What is Mebeverine ?
Antispasmodic used in IBS. MOA unclear, but decreases Ca entry into gastric SM cells so fewer spasm episodes.
190
What drug could have ADR on a px of; indigestion, constipation, rash and dry skin ?
Mebeverine
191
What drug tx is used as an antidiarrhoeal eg. for acute non infective diarrhoea ?
Loperamide , mu opioid receptor agonist. Decreases myenteric plexus electrical activity that then relaxes GI SM tone ^ peristalsis.
192
What brand name is Loperamide often sold under ?
Imodium
193
What is prednisolone?
Anti inflammatory, can be used in UC. binds to steroid receptor, acts as gene transcription regulator ^ anti inflammatory protein synthesis but decreases inflammatory immune factor synthesis.
194
What are the contraindications of prednisolone ?
If immunosuppressed or have active infection
195
Why might Cinchocaine and hydrocortisone by used together ?
Haemorrhoid tx. Combinations often include peripheral vasoconstrictors eg. phenylephrine + LA + Anti inflam.
196
What is the function of a LA ?
Local anaesthetic. Blocks Na voltage gated channels in nociceptive nerve fibres. Forces nerve to ^ refractory period and prevent pain AP along axon to CNS.
197
When would you not give Cinchocaine for haemorrhoid tx ?
Heart block or WPWS arrhythmias. If already on class 1 anti arrhythmic drugs
198
At what vertebrae levels are the 4 parts of the duodenum?
Bulb at L1
Sup duodenal flexure to inf flexure L2
Inf duo flexure to midline L3
Midline to ligament of Treitz L2
199
Which parts of the duodenum are retroperitoneal ?
Parts 2, 3 and 4
200
How would you test for Perforation ?
Use an erect chest X ray, view collection around the 'hole'
201
How would you distinguish the small and large bowel in an abdominal x ray ?
Small; central location, gas/fluid filled, calculate conniventes, calibre <3 cm diameter
Large; Peripheral location, faeces, hausfrau, calibre <5 cm diameter.
202
How would the large bowel change during toxic megacolon or perforation ?
Calibre ^ to above normal range. Abnormal >8cm.
| Haustra disconnected, don't cross entire width of wall.
203
What is pneumatosis ?
Gas within the wall of the bowel. Just before the bowel perforates. Bowel wall ischemic as under too much pressure
204
What is the name given to abnormal gas filled loops in the colon ?
Pseudo obstruction. Common in the elderly, tend to be on Parkinson's medication
205
How would perforation be indicated on a chest X ray ?
px has to be erect long enough for gas to rise. Air released into peritoneal space. Free air under diaphragm shows upper edge of liver and lower edge of diaphragm (usually isn't seen due to soft tissue and fluid).
206
What are Rigler's signs ?
Air is seen on both sides of intestine (lumen and peritoneal side of wall). Triangles of gas (low density=dark) show leakage into peritoneal space.
207
What is the term given to a large pneuma-peritoneum where gas rises above abdominal wall?
Falciform or Football sign. Liver rises from falciform ligament, shows gases either side.
208
How is a Ba follow through carried out and how would Crohn's be indicated ?
Just SB, px drink liquid containing Barium to coat the lumen.
Crohn's shows superficial inflammation (cobblestoning). deep ulceration through bowel. Contrast goes through bowel wall transmurally.
209
What test would be used to assess the colon mucosa in detail to help identify cancers and polyps ?
Barium enema, just LB. Px given laxative and rectal tube inserted (Ba + CO2) in a double contrast study.
210
What is diverticular disease and what does it have a similar presentation to ?
Out pouches of mucosa through bowel wall. Can lead to inflammation and fever with an acute presentation similar to appendicitis.
211
What are the limitations of a Ba enema ?
Mobility (requires regular turning) , anal tone, inadequate bowel prep common, overlap of bowel oops common
212
What is the advantage of using an IV contrast during CT scans ?
Gives an enhanced view of the soft tissue and tumours. Useful for identifying blocked areas. Contains Iodine
213
How does the appearance of an oral contrast vary ?
Contains -ve (H2O) which is dark. Enhances wall/mucosal pattern. Shows outside of bowel.
And the +ve (iodine based drink) which is bright. Helps identify fistulas.
214
What is Comb sign ?
The hyperactive mesentery seen with Crohn's disease. Lines of inflammation look like a hair comb.
215
How is the pain felt in; haemorrhoids, fissures and fistulas and how would you tx them initially ?
Haemorrhoids, intense pain with palpable lump when bowel opens
Fissures, tearing of anus able to pinpoint pain when straining
Fistulas, passage of outside of anus through sphincter that causes intense pain or asymptomatic.
Relax the anal can with GTN spray or Dilitiazem cream
216
What is an end colonoscopy ?
End of colon exposed, Hartmann's op removes rectum+sigmoid , contents similar to stool. Used in early management
217
What are the complications with ileostomy ?
More problems in op and may be watery so need antidiarrhoeals to prevent dehydration.
218
What are the two types of ileostomy?
End; UC px removes LB, green and thick contents relative to amount of SB still present
Loop; Some SB attached to skin, diverts the stool downstream of the stoma.
219
What is a Colostomy and what are the advantages over CTC ?
Direct visualisation of inside of bowel that allows for biopsy (CTC doesn't with same prep).
Look right into terminal ileum so useful for Crohn's/UC diagnosis.
CT colonography
220
What is ERAS , give some examples ?
Enhanced recovery after surgery
stop smoking, anaesthetic choice, pre-op nutrition etc.
Helps delay fear, hypothermia, organ dysfunction, electrolyte imbalance etc.
221
What is the advantage of laparoscopic over open surgery?
Smaller incision so less pain and able to breath better post op. Coughing/breathing deeply post op can be painful. More likely to mobilise faster and to ^ level.
222
What are the two curves of the colon ?
Right - Hepatic flexure
| Left - Splenic flexure
223
The SM cells within the GI are syncytium , what does this mean ?
group of cells that share cytoplasm so act as one. AP spreads rapidly from cell to cell and allows electrolytes to move freely between cells.
224
What are cajal cells ?
Sit between layers of SM, act as pacemaker cells of the gut SM. Initiate slow wave pattern that oscillates between resting and -40mv.
225
What is the myenteric plexus ? what sensory info do they deliver ?
Interconnection of neurones above musculature of the gut. Has afferent sensory nerves that deliver info to interneurones in plexus; stretch and chemo.
226
What is the response when a strong impulse is initiated in stretch and chemo receptors ?
Stretch/chemo > info to interneurons > efferent nerves to SM cells > stimulation with AP (spike waves) > muscle contraction.
227
Apart from stretch/chemo receptors, how else is contraction stimulated ? How does this relate to tx?
ACh from parasympathetic nerves.
| Anticholinergic meds help constipation eg. antihistamines (Benadryl).
228
What are the effects of ; parasympathetic , sympathetic and stress on peristalsis ?
Para; stimulates
Sypma; inhibits in extremes , high A/NA all or nothing
Severe stress; complete stop
229
What is the effect of a bolus of food intake ?
Stimulates stretch receptors > circular muscles contract then longitudinal muscles contract to shorten tube. Then circular again just after bolus rely to push food down in waves.
230
Where does the roughly 9L of fluid/day go and how is it absorbed ?
100ml/day in urine excretion. SI absorbs 8.5L. LI absorbs 100-400ml but can be up to 9L.
Absorbed through passive osmotic forces, paracellularly through tight junctions in lining of SI/LI.
231
What is the effect of some drugs eg. Epsom salts, on absorption ?
Can alleviate constipation (Mg sulphates).
| Poorly absorbed creates osmotic force that pulls H2O out of body to liquify the stools. Lactulose does the same
232
What is the difference between trans and paracellular movement ? How is the lumen charged ?
Transcellualr resistance > para due to voltage difference between SI lumen and intestinal fluid surrounding cells. Lumen is -ve because Na are the main ion to be absorbed.
233
What can cause abnormalities of the tight junctions ?
TJ targeted by E coli, they break them down allowing bacterial products/dietary antigens through into lamina propria. This then allows larger structures eg. dendritic cells, macrophages to pass through.
234
What are the key proteins that regulate tight junction function ?
Claudins, occludins and includins
235
Where is Na absorbed, through what method, which carrier, how can this be used in tx?
Absorbed in the jejunum through co-transport with glucose (SGLT1) and H+.
Can be used for rapid oral rehydration through Na dependant glucose uptake SGLT1 drugs ^ H2O uptake.
236
Where is K absorbed and secreted. What is secretion stimulated by in different membranes ?
Absorbed in jejunum. Secreted throughout SI, in colon secretion stimulated by ^ aldosterone channels in apical membrane and ^NaK ATPase in basolateral membrane.
237
How is Ca absorption stimulated and how is this substance made ?
active absorption stimulated by Calcitriol. Released from kidneys (produced using Vit D). Vit D taken up/broken down by liver, goes to kidneys and converted to Calcitriol.
238
How is Ca absorbed passively, where does this take place, through what channels. What do the channels respond to ?
Paracellular uptake in Duo/ileum through TRPV (transient receptor potential channels).
Channels respond to ^temp (pain, curry - Capsasin)
239
How is ferric state iron (found in meat) absorbed ?
converted in SI to Ferras (Fe2+) ^ h2o solubility through reductase enzymes and conc of H/bile acids in duodenum. Uptake in duo through enterocytes. Either stored as ferritin or taken out of basolateral membrane and complexed into transferrin.
240
What is transferrin ?
Large macromolecular that prevents iron loss in portal circulation. Used to transport iron.
241
Where are Cl and HCO3 absorbed ?
Cl, duodenum passive (lumen -ve pd) cotransport with Na/HCO3 exchange
HCO3, ileum. HCO3 in LI neutralises bacterial flora.
242
What are the action of NANC ?
enteric hormones, non adrenergic non cholinergic. Release VIP > acts through PKA + cAMP to ^ Cl by ^ pKa/cAMP to ^ H2O loss.
243
What is Verner-Morrison syndrome ?
Pancreatic tumour that ^ VIP to give watery diarrhoea.
244
What is the function of EC cells and how is this related to SSRIs ?
Enterochromaffin. secrete serotonin > stimulates pKc > ^Ca turnover in enterocytes > ^ Cl out.
Antidepressants (eg. Fluoxetine) targets CNS but gives ADR of diarrhoea because can also target the gut
245
What is the function of D cells ? what problems can arise if they malfunction ?
Produce somatostatin which regulates Na/Cl absorption.
| Patho - DM, diarrhoea, weight loss etc.
246
Enteric neurones can release enkephalins, what is their function ? How can this relate to clinical drugs ?
They are opioid transmitters important for NaCl absorption. Diarrhoea relief tablets contain emprimide (opioid substance) that helps dry out the stools.
247
What substances give excitatory and inhibitory effects during SI/LI motility ?
Excite - substance P + ACh
| Inhibit - VIP, NO (short half life)
248
What is the meaning of 'segmentation' during post prandial SI contractions ?
Circular muscle creates pinching affect around bolus in non propulsive movement in preparation for peristaltic waves.
249
What is the migrating motility complex and when does it occur ?
Occurs during fasting every 1.5 Horus. Long range contraction 'flushes' contents along the whole length of the intestine.
250
What response does a moving bolus initiate ?
triggers stretch receptors, widen path ahead narrows lumen behind.
Longitudinal muscle in front of bolus contract and behind it relaxes
Circular in front relaxes and behind contracts.
251
What is the SIP synctium composed of ?
SM cells , Interstitial cells of cajal (ICCs) , Platelet derived growth factor receptor a+ cells (PDGFRa+)
252
What are the function of N cells in the ileum ?
Release neurotensin in terminal SI in response to fat. decreases motility (fat normally all absorbed in ileum so if any might get through neurotensin ^ to allow ^ time for absorption).
253
What is the function of L cells and what do they respond to?
In the distal ileum they release GLP-1 to reduce motility and ^ absorption.
Released in response to ^ glucose and fat
254
What cells release motilin in response to ^ fat and acid. What is the effect of Motilin ?
M cells in the duodenum.
| ^ Sensitivity reflex in SI so normal intrinsic activity ^. Used in fasting to wash away any small debris. §
255
What is Hirschprung's disease ?
SM prefers contraction it needs inhibitory neurones to relax. Myenteric plexus becomes ganglionic so no relaxation occurs. Proximal build up of mass/matter
256
What type of muscle is the external anal sphincter and what nerve is it innervated by ?
Skeletal muscle (voluntary) . innervated by the pudendal nerve (poodendal).
