UTI, GI infections

Question 1

range of urinary tract infections

Answer 1

–Urethral syndrome –Cystitis –Pyelonephritis –Renal abscess –Sepsis syndrome (‘septicaemia’; ‘bloodstream infection’) –Renal calculi with infection

Question 2

define bacteriuria

Answer 2

the presence of bacteria in urine

Question 3

significant bacteriuri (define)

Answer 3

large numbers of one type of bacteria in tthe urine

Question 4

define pyuria

Answer 4

the presence of pus cells in the urine

Question 5

uropathogens

Answer 5

E. coli Enterococcus sp Staph saprophyticus Staph aureus Klebsiella sp Enterobacter sp Proteus sp Pseudomonas Candida/adenovirus

Question 6

Bacterial factors for infection

Answer 6

Mostly derived from gut flora – enter urethra via perineum, and ascend to bladder •Multiply rapidly in urine •Large inoculum favours infection •Some bacteria have specific virulence factors e.g. fimbriae (sometimes called pili (sing. pilus)) •They have features that enhance resistance to host immunity

Question 7

virulence factors in e. coli for UTs

Answer 7

•Uropathogenic E. coli clones •Cystitis and pyelonephritis strains distinct. •Virulence factors: adhesins, P & F , haemolysin, K-antigen, endotoxin/exotoxin. •Close regulation of gene expression

Question 8

Host factors for infection

Answer 8

•Short urethra •Pregnancy •Sexual intercourse •UTI abnormality •Urine abnormality •Urinary catheter/instrumentation

Question 9

CA-UTI extraluminal

Answer 9

early: by insertion Late: by capillary action

Question 10

CA-UTI intraluminal

Answer 10

break in the seal

Question 11

how many HAI are CA-UTI?

Answer 11

20%

Question 12

how many HA-UTI relate to catheters?

Answer 12

65%

Question 13

how much each CA-UTI costs>

Answer 13

1200GBP

Question 14

Types of urinary catheters:

Answer 14

•Standard silicone bladder catheters •Condom-style catheters •Silver-impregnated catheters •Intermittent self-catheterisation •Suprapubic catheters

Question 15

ways to obtain CSU specimen

Answer 15

•‘CSU’ – aseptically-removed urine from a long-standing catheter or bag? •‘CSU’ - a sample taken by brief catheterisation

Question 16

Definition of CA-UTI

Answer 16

•An infection occurring in a person whose urinary tract is currently catheterised OR has been catheterised within the previous 48 h

Question 17

clinical manifestations of UTI

Answer 17

•May be asymptomatic •Dysuria, frequency, urgency, polyuria, suprapubic pain & tenderness •Loin pain, fever & malaise, rigors •Haematuria •Babies – failure to thrive, convulsions •Elderly - confusion, fevers, urine ‘off’ •Renal colic if stones •Occasional incontinence

Question 18

types of diagnostic specimens for urine

Answer 18

•MSU – mid-stream urine •CSU – catheter specimen of urine •‘Clean catch’ •Bag urine (infant) •SPA - supra-pubic aspirate •EMU – early morning urine (for TB) •Terminal – final part of urine stream (for schistosomiasis) •Others e.g. renal calculus or sample from ureter •NB Blood cultures if septicaemic

Question 19

laboratory examination of urine criteria How many bacteria is significant? Is it normal for catheterised patients to have organisms in urine? Is it normal in suprapubic urine?

Answer 19

•Classically if > 10^5 bacteria per ml (one type only) then this is significant. In practice lower numbers likely significant in pure growth. •This cut-off is used as a few organisms normally come from the urethra and contaminate the urine. •Catheterised patient – catheter urine nearly always has organisms after a few days. •Suprapubic urine – should be sterile

Question 20

Mangement of UTIS

Answer 20

•Non-specific •Specific: Trimethoprim, cephalosporins, nitrofurantoin, [amoxicillin], [ciprofloxacin] –Typically 3 or 5 days (7 d male, pregnant woman) •Severe (?pyelonephritis): IV co-amoxiclav +/- gentamicin OR cefuroxime –Typically 7-10 days •Prophylaxis – Trimethoprim, nitrofurantoin; cranberry juice? •Radiological imaging, IVU, Ultrasound, CT etc •Surgical correction of abnormalities

Question 21

what abx can you use in pregnancy for uti?

Answer 21

cephalosporins, nitrofurantoin, [amoxicillin], cefuroxime

Question 22

management of UTI in hospital

Answer 22

•Don’t treat catheter colonisation only •Check for recent urine cultures and recent antibiotics to guide treatment •Non-compromised (no sens, not severe): best guess: oral co-amoxiclav; nitrofurantoin –Typically 5 days •Compromised/Severe: IV piperacillin-tazobactam (or meropenem if known MDR pathogens) +/- gentamicin; OR ciprofloxacin (+/- gent) if allergy –Typically ~7 days •Change catheter if present

Question 23

becteria resistance in UTIs

Answer 23

• In General Practice: ESBL- producing E.coli and other coliforms • Resistant to nearly all oral agents and often IV ones also • Even if patient has not been in hospital recently

Question 24

common communit acquired GI bacteria

Answer 24

●Campylobacter spp ●Salmonella spp – food poisoning & enteric fever species ●Shigella spp ●Escherichia coli - various types e.g. enteropathogenic, enteroinvasive; also E. coli O157 ●Vibrio cholerae [travellers] ●Toxin-producers: Clostridium perfringens, Cl. botulinum, Staphylococcus aureus ●Helicobacter pylori: Gastric infection

Question 25

Viruses and parasites (GI) in community

Answer 25

Rotabirus, norovirus, Giardia, Cryptosporidium, worms

Question 26

Hospital acquired GI infections

Answer 26

C Diff Norovirus

Question 27

GI organisms in immunocompromised

Answer 27

●Clostridium difficile, Norovirus PLUS any community-acquired organism ●CMV, Mycobacterium avium, Isospora etc

Question 28

GI infections specifically of concern in sickle cell pateints

Answer 28

SICKLE CELL PATIENTS ●Special concern about Salmonella – can be disseminated and cause osteomyelitis

Question 29

uk epidemiology of GI infections

Answer 29

□Campylobacter (87 cases per 100,000) □Salmonella (21 cases) □Cryptosporidium (9 cases) □Escherichia coli 0157 (2 cases

Question 30

Specific toxins & other virulence factors S aureaus C Botulinum V cholerae E coli Helicobacter pylori Shigela C diff

Answer 30

●Staph aureus toxin, Botulinum toxin in food (i.e. not strictly GI infections) ●Cholera toxin ●E. coli LT toxin (very similar to cholera toxin) & ST ●VTEC (i.e. vero-cytoxin producing E. coli) e.g. strain O157 – if severe, haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) ●Helicobacter urease, cagA ●Shigella shiga toxin ●Clostridium difficile toxin A+B

Question 31

Clinical features of GI infection

Answer 31

●Diarrhoea! More than 3 in a day & sample takes shape of pot ●May be blood and/or pus in stool, or just watery ●Nausea & vomiting ●Fever & systemic illness uncommon – of concern ●Abdominal pain/cramps ●Often lasts only a day – self limiting ●Dehydration & Na+ & K+ depletion, esp. children (can lead to death) □?Travel history ?Antibiotic history ?Immunocompromised

Question 32

Amoeboids Distribution How humans get infected what can cysts survive and not?

Answer 32

□Worldwide distribution □Free-living environmental species e.g. Acanthamoeba, Naegleria □Human pathogens - ingestion of cysts contaminating food/water. E.g. Entamoeba histolytica □Only some strains of amoebae cause disease; non-pathogenic amoebae found in normal gut (e.g. Entamoeba coli; Iodamoeba) □Cysts survive water chlorination (e.g. tablets): destroyed at 50oC

Question 33

Entamoeba histolytica Distribution Diseases caused Diagnosis/ Ix Tx

Answer 33

□Asia, Africa, S America; faecal-oral spread - ingestion of cysts contaminating food/water. □Amoebic dysentery, flask-shaped ulcers in colon; Liver (& occasionally lung/other) abscess □Diagnose by examining a “hot stool” for amoebae; also serology (amoebic FAT). Metronidazole treatment for dysentery, abscesses; diloxanide follow up to kill residual cysts. □Non-pathogenic E. dispar

Question 34

clinical syndrome with amoebae infection

Answer 34

□Intestinal disease ●Asymptomatic ●Dysentery, toxic megacolon, amoeboma. Perianal ulceration □Extra-intestinal disease ●Liver abscess with or without peritonitis, empyema, pericarditis ●Lung & brain abscess

Question 35

TYPICAL PRESENTATION OF AMOEBA DISEASE

Answer 35

Presentation - Intestinal ●History days to weeks ●Diarrhoea +/- blood & mucus ●Abdo pain & tenderness ●Weight loss ●Fever (30-40%) □Extra-intestinal disease ●Depends on site: fevers, plus RUQ pain (liver), + abdo pain; cough, chest pain (lung) seizures (CNS)

Question 36

diagnosis and treatment of amoeba disease

Answer 36

□‘Hot stool’ sample! – microscopy for trophozoites x 3 □Stool for cysts □Colonic biopsy/histology □Aspiration of abscess □Amoebic serology (IFAT) □Metronidazole treatment of all acute infections □Diloxanide to kill gut cysts

Question 37

Classes of parasitic worms

Answer 37

Roundworms (Nematodes) □Adult and larval roundworms cylindrical & inhabit intestinal and extraintestinal sites. Flukes (Trematodes) □Adult flukes are leaf-shaped flatworms. The life-cycle includes a snail intermediate host. Tapeworms (Cestodes) □Adult tapeworms are elongated, segmented flatworms that inhabit the intestinal lumen. Larval forms inhabit extraintestinal tissues.

Question 38

species of roundworms

Answer 38

□Ascaris lumbricoides □Whipworm (Trichuris trichiura) □Hookworms (Necator, Ancylostoma) □Pin worm (thread worm) (Enterobius vermicularis) □Strongyloides stercoralis □Animal roundworms □[Non-GI: ‘Tissue nematodes’: Filiariasis, Dracunculiasis, Trichinosis]

Question 39

Ascaris lumbricoides epidemiology distribution

Answer 39

□1-1.5 bn infected □Distribution: mostly tropics, warm temperate if poor sanitation □Most asymptomatic □60,000 deaths/yr

Question 40

ascaris lumbricoides basic life cycle

Answer 40

●ingest ova directly or in water (faecal contamination), ●larvae penetrate gut, migrate through lungs ●larvae coughed up & swallowed, ●male & female adults in small bowel ●ova excreted in faeces. □Children most heavily infected □Faeces used for fertilising crops □80% of people in endemic areas □Eggs viable up to 6 yrs □One egg ingested=one worm □In UK mostly travellers/immigrants from endemic areas

Question 41

clinical features of ascaris lumbriocoides

Answer 41

□Asymptomatic □Pulmonary hypersensitivity response to migrating larvae – cough, fever, eosinophilia; CXR changes in some □Mild abdo discomfort, nausea, dyspepsia □Heavy worm burden e.g. 50-500 worms: (exacerbate) malnutrition; intestinal obstruction; perforation; cholangitis; secondary sepsis

Question 42

Diagnosis and Tx of ascariasis

Answer 42

Diagnosis □Stool examination □Larvae in sputum or gastric aspirate □Discovery at gut surgery or endoscopy Treatment: □Mebendazole □(Surgery

Question 43

Whipworm (trichuris trichiura) distribution epidemiology

Answer 43

Whipworm (Trichuris trichiura) □1 bn people infected (co-infection Ascaris) □Distribution: tropics - poverty □Most asymptomatic □Heavy infestation: Dysentery-type syndrome; rectal prolapse; Fe deficiency anaemia, growth retardation

Question 44

Whioworm - trichuris trichiura basic life cycle

Answer 44

●ingest ova directly or in water (faecal contamination); male & female adults in epithelium of caecum/colon; ova excreted in faeces

Question 45

Pin worm (thread worm) (enterobius vermicularis) epidemiology and basic life cycle

Answer 45

□Disease: Enterobiasis □0.5 bn? people infected, most children □Distribution: worldwide inc temperate zones □Most asymptomatic □Perianal itching; ?appendicitis □Basic life cycle: ●ingest ova directly on hands; larvae hatch, form adult in caecum; female adult migrates through anus, lays ova peri-anally; ova contaminate hands/nails

Question 46

hookworm (necator americanus, ancylostoma duodenle epidemiology clinical fetures

Answer 46

□Disease: Hookworm □1-1.5 bn people infected □Distribution: Tropical, subtropical zones □Most asymptomatic; Fe deficiency anaemia □Basic life cycle: ●Filariform larvae penetrate skin, migrate through lungs; larvae coughed up & swallowed, male & female adults in duodenum; ova excreted in faeces, larvae mature 1-2 days from rhabditiform to filariform. Clinical: □“Ground Itch” at site of penetration of skin □Transient pneumonitis □Diarrhoea, abdo discomfort in new host □Eosinophilia □Iron deficiency anaemia □Treatment: albendazole / mebendazole

Question 47

Strongyloides stercoralis

Answer 47

□30-300 m people infected □Distribution: Tropical, subtropical zones □Most asymptomatic; hyperinfection syndrome □Basic life cycle: ●Filariform larvae penetrate skin, migrate through lungs; larvae coughed up & swallowed; female adults in duodenum/jejunum; eggs through parthenogenesis, hatch into rhabditiform larvae in mucosa (into faeces) which then develop into filariform larvae [free-living male/female cycle] ●Some filariform larvae form in host - autoinfection Clinical: Acute: □Rash at site of penetration of skin □Transient pneumonitis □Diarrhoea & abdo pain, eosinophilia Chronic: Infection regulated by cell-mediate immunity □Asymptomatic (50% or perianal rashes, abdo pain, fluctuating eosinophilia)

Question 48

strongyloides in the compromised host

Answer 48

Steroids, lymphomas, leukaemias, HTLV-1, [HIV] Hyperinfection syndrome □Increased numbers in lung, gut Dissemination □Larvae also in CNS, kidneys, liver, etc □Often no eosinophilia □Gut ulceration, sepsis syndrome & meningitis, GI haemorrhage, pneumonitis □Diagnosis: ●Clinical awareness of residency in risk country at time of immunosuppression ●Larvae in stool, sputum ●Biopsies of tissue ●Antibody studies □Treatment: ivermectin / thiabendazole; reduce immunosuppression

Question 49

Trichinella spiralis

Answer 49

□Eat meat containing larval cysts □In stomach larvae released, in small intestine mucosa develop into adult worms □Adults produce larvae which enter host skeletal muscle □Form cyst, may calcify □Myositis, periorbital oedema, fever, eosinophilia □Possibly mebendazole

Question 50

FLukes

Answer 50

□Liver flukes: Clonorchis, Opisthorcis, (biliary tree; mainly Asia; snail-fish cycle, humans eat undercooked fish); Fasciola (sheep liver fluke: snail, watercress, gut lumen, peritoneum, liver) □Intestinal flukes: Fasciolopsis (pigs mainly - snail, watercress, gut lumen only) □Lung flukes: Paragonimus (snail, crustaceans, gut, peritoneum, lung)

Question 51

tapeworms (Cestodes)

Answer 51

□Pork Taenia solium □Beef T. saginata □Fish Diphyllobothrium □From dogs: Hydatid Echinococcus granulosus, E. multilocularis