Gastrointestinal infections

 

 

Among the most common infections in the world

 

Diarrhoea, vomiting, abdominal pain, malaise, possible pyrexia

 

Faecal - oral

 

 

 

Environmental factors

 

Sanitation

Water supplies

Ambient temperatures and frost

Levels of education

Personal and community hygiene

 

 

Transmission

 

Water - food - secondary spread

 

 

 

Natural defences

 

Gastric acid - infections common in achlorhydria

 

Bile salts - disrupt the membranes of some bacteria

 

Normal bowel flora - competition between micro-organisms, e.g. salmonella infection more likely after antibiotics

 

Immune responses - lymphocytes in mucosa, cell mediated and humoral immunity (Ig A), lymphoid tissue, enjoyed when OPV is given, colostrum

 

Motility - blind loops become infected may lead to abscess formation, faeces weight 50% bacteria, stasis ferments gut contents, diarrhoea flushes

 

Protection against toxins - some normally produced, the hepatic portal circulation

 

 

Principles of management

 

Specimens -  stool, mucosal, intestinal fluid, vomit, blood cultures

 

Oral rehydration - Sodium 150 - 155 mmol/l, Glucose, 200 - 220 mmol/l, Potassium 4 - 5 mmol/l

 

Intravenous rehydration - half strength saline, monitor electrolyte balance

 

Feed children with diarrhoea

 

Lactose intolerance may temporally occur after GI infection in children

 

 

Drug treatment

 

Antiemetics

Antidiarrhoeal drugs

 

 

Prevention of food poisoning

 

Clean water supplies

 

Safe food production and manufacture

 

Prevent cross contamination e.g. uncooked to cooked meat

 

Kill salmonella

 

Cooking

 

Notifiable

 

 

Viral infections

 

May be caused by a variety of viruses, e.g. adenoviruses, small round structured viruses, small round viruses, astroviruses

 

 

Rotavirus

 

Common in young children, adults are often immune

 

Epidemiology            - most infections occur in winter

Clinical picture         - abrupt onset of diarrhoea and vomiting, possible mild                                     pyrexia

Incubation                 - 24 hours

Duration                    - usually 1 - 2 days

Management            - keep hydrated, avoid dairy products - low lactose milk

Diagnosis                  - useful for outbreaks is by electron microscopy

 

 

Bacterial infections

 

 

Escherichia coli

 

Commensal and pathogenic types

 

Epidemiology

Very transmissible, from animals

 

Clinical picture

Abrupt onset of diarrhoea and vomiting, possible moderate fever, followed by watery diarrhoea

 

Incubation

1 - 2 days up to 5 days

 

Duration

Usually 1 - a few days

 

Management

Keep hydrated, early recognition of complications, possible ciprofloxacin

 

Diagnosis

Epidemiology, clinical picture, culture

 

Complications

From some forms of E. coli - Haemorrhagic colitis, Haemolytic uraemic syndrome

 

Prevention

Close down source, prevent cross infection, cook hamburgers, avoid infection while travelling

 

 

Salmonella

 

2 200 different serotypes which are found in people and animals, eg. poultry pigs and cows

 

 

 

Infection

 

From infected animal material, e.g. poultry (60% infected) egg shells, egg white, raw meat

 

Faecal-oral

 

 

Pathophysiology

 

An infection of the gut epithelium

 

Excess fluid secretion from small bowel

 

 

Clinical features

 

Incubation 18 - 36 hours

 

Malaise, nausea, vomiting, often fever followed by diarrhoea

 

Diarrhoea is watery and brown and may later become greenish

 

Not a lot of abdominal pain except on call to stool

 

Normally resolves in 2 days but may go on for several weeks leading to debility

 

 

Complications

 

Elderly at risk from low fluid volumes which may lead to MI and CVA

 

Salmonella colitis - up to 10% of patients may develop colic and bloody stools

 

Salmonella bacteraemia - uncommon, possible metastatic infection, may occur in the absence of clinical bowel infection

 

Continued excretion after recovery, usually stoops within 4 weeks

 

 

Management of salmonellosis

 

Rehydrate and await spontaneous recovery

 

IV fluids for dehydration or exhaustion

 

Antibiotics if no recovery after 36 - 48 hours, e.g. ciprofloxacin

 

Shegellosis (bacillary dysentery)

 

Shigellosis is generally mild in the West but severe in the tropics, especially in children

 

Infection

Faecal-oral - direct, water, food

Mostly in children under 5 years

 

Clinical features

Incubation 3 - 4 days

Starts with a high fever lasting 12 - 24 hours

Diarrhoea with colitis and colic

Brown watery diarrhoea often with mucus, may be some blood

Recovery is usual in 3 - 5 days

 

Management

Maintain hydration

Antibiotics if persistent

Antispasmodics for colic

 

 

Campylobacter

 

Most common food poisoning in the UK, 40 000 reported cases per year

Very limited person to person spread

Very few metastatic of bacteraemic complications

 

Infection

Mostly from poultry or wild birds drinking human milk

Most cases in Summer

Infective dose may be as low as 500 organisms

 

Clinical features

Incubation 3 - 4 days

24 hour prodromal pyrexia, headache and prostration

Diarrhoea - watery and possibly bloody

Vomiting at outset

Abdominal pain common with possible rebound tenderness

Fluid accumulates in bowel loops from action of the toxin

 

Management

Symptomatic treatment

Specific treatment of prolonged, oral erythromycin

 

Prevention

Good hygiene

Get it out of poultry

 

Other bacterial causes

 

Vibrios - from shellfish

Yersinia

Helicobacter pylori - acute gastritis, chronic gastritis, peptic ulceration, human to human infection

 

 

Food poisoning caused by toxins

 

Staphylococcal

Incubation 30 mins - 6 hours

Malaise, nausea, severe vomiting

Possible iv. emergency rehydration required

 

Botulism

Clostridium from poorly  canned or bottled food

Usual picture followed by neuromuscular paralysis from the head down including swallowing and respiration

Incubation 24 - 48 hours, Consider antitoxin or polyvalent antiserum

 

 

Parasitic infections

 

Protozoa

Giardia, other amoeba, amoebic dysentery

 

Helminths

Among the commonest chronic conditions in humans

Endemic in areas of poor sanitation

Faecal - oral usually

Produce eosinophilia

 

Threadworms

Mebendazole

 

Ascaris

Respiratory features due to larvae migrating through the lungs, Mebendazole

 

Hookworms

Larvae get in through the skin, migrate to the lungs, are swallowed and infect the gut, eggs are excreted with faeces

Treat anaemia, Mebendazole

 

Strongyloides

Similar to hookworm treat with albendazole for 3 days

 

Bannister BA.  Begg NT. Gillespie SH. (1996)  Infectious diseases,  Blackwell Scientific, Oxford

 

 

 

 

Gastrointestinal infections

 

 

Among the most common infections in the world

 

Diarrhoea, vomiting, abdominal pain, malaise, possible pyrexia

 

Faecal - oral

 

 

 

 

Environmental factors

 

Sanitation

Water supplies

Ambient temperatures and frost

Levels of education

Personal and community hygiene

 

 

Transmission by water,  food, secondary spread

 

 

 

Natural defences

 

Gastric acid - infections common in achlorhydria

 

Bile salts - disrupt the membranes of some bacteria

 

Normal bowel flora - competition between micro-organisms, e.g. salmonella infection more likely after antibiotics

 

 

Immune responses - lymphocytes in mucosa, cell mediated and humoral immunity (Ig A), lymphoid tissue

 

Motility - stasis leads to infection, may lead to abscess formation

 

Diarrhoea flushes

 

Faeces weight 50% bacteria,

 

 

Protection against toxins - the hepatic portal circulation

 

 

 

 

 

 

 

 

 

 

 

 

 

Principles of management

 

Specimens -  stool, mucosal, intestinal fluid, vomit, blood cultures, vomit

 

Oral rehydration

 

Intravenous rehydration - half strength saline, monitor electrolyte balance

 

 

Feed children with diarrhoea

 

Lactose intolerance may temporally occur after GI infection in children

 

 

 

 

 

 

 

 

 

Drug treatment

 

Antiemetics

 

Antidiarrhoeal drugs

 

 

 

 

 

 

 

 

 

Prevention of food poisoning

 

Clean water supplies

 

Safe food production and manufacture

 

Prevent cross contamination e.g. uncooked to cooked meat

 

Kill salmonella

 

Cooking

 

Viral infections

 

Causes, e.g. adenoviruses, small round structured viruses, small round viruses, astroviruses

 

 

 

 

 

 

 

 

 

Rotavirus

 

Common in young children, adults are often immune

 

Epidemiology - most infections occur in winter

 

Clinical picture - abrupt onset of diarrhoea and vomiting, possible mild     pyrexia

 

Incubation - 24 hours

 

Duration - usually 1 - 2 days

 

Management - keep hydrated, avoid dairy products

 

Diagnosis - useful for outbreaks is by electron microscopy

 

 

 

 

 

xxxxxxxxxxxxxxxxxxxx

Bacterial infections

 

Escherichia coli

 

Commensal and pathogenic types

 

Epidemiology - very transmissible, from animals

 

Clinical picture - abrupt onset of diarrhoea and vomiting, possible moderate fever, followed by watery diarrhoea

 

Incubation - 1 - 2 days up to 5 days

 

Duration - Usually 1 - a few days

 

Management - keep hydrated, early recognition of complications, possible ciprofloxacin

 

Diagnosis - epidemiology, clinical picture, culture

 

Complications

From some forms of E. coli - Haemorrhagic colitis, Haemolytic uraemic syndrome

 

Prevention

Close down source, prevent cross infection, cook hamburgers, avoid infection while travelling

 

 

Salmonella

 

2 200 different serotypes which are found in people and animals, eg. poultry pigs and cows

 

 

 

Infection

 

From infected animal material, e.g. poultry (60% infected) egg shells, egg white, raw meat

 

Faecal-oral

 

 

Pathophysiology

 

An infection of the gut epithelium

 

Excess fluid secretion from small bowel

 

 

Clinical features

 

Incubation 18 - 36 hours

 

Malaise, nausea, vomiting, often fever followed by diarrhoea

 

Diarrhoea is watery and brown and may later become greenish

 

Not a lot of abdominal pain except on call to stool

 

Normally resolves in 2 days but may go on for several weeks leading to debility

 

 

Complications

 

Elderly at risk from low fluid volumes which may lead to MI and CVA

 

Salmonella colitis - up to 10% of patients may develop colic and bloody stools

 

Salmonella bacteraemia - uncommon, possible metastatic infection, may occur in the absence of clinical bowel infection

 

Continued excretion after recovery, usually stoops within 4 weeks

 

 

Management of salmonellosis

 

Rehydrate and await spontaneous recovery

 

IV fluids for dehydration or exhaustion

 

Antibiotics if no recovery after 36 - 48 hours, e.g. ciprofloxacin

 

Shegellosis (bacillary dysentery)

 

Shigellosis is generally mild in the West but severe in the tropics, especially in children

 

Infection

Faecal-oral - direct, water, food

Mostly in children under 5 years

 

Clinical features

Incubation 3 - 4 days

Starts with a high fever lasting 12 - 24 hours

Diarrhoea with colitis and colic

Brown watery diarrhoea often with mucus, may be some blood

Recovery is usual in 3 - 5 days

 

Management

Maintain hydration

Antibiotics if persistent

Antispasmodics for colic

 

 

Campylobacter

 

Most common food poisoning in the UK, 40 000 reported cases per year

Very limited person to person spread

Very few metastatic of bacteraemic complications

 

Infection

Mostly from poultry or wild birds drinking human milk

Most cases in Summer

Infective dose may be as low as 500 organisms

 

Clinical features

Incubation 3 - 4 days

24 hour prodromal pyrexia, headache and prostration

Diarrhoea - watery and possibly bloody

Vomiting at outset

Abdominal pain common with possible rebound tenderness

Fluid accumulates in bowel loops from action of the toxin

 

Management

Symptomatic treatment

Specific treatment of prolonged, oral erythromycin

 

Prevention

Good hygiene

Get it out of poultry

 

Other bacterial causes

 

Vibrios - from shellfish

Yersinia

Helicobacter pylori - acute gastritis, chronic gastritis, peptic ulceration, human to human infection

 

 

Food poisoning caused by toxins

 

Staphylococcal

Incubation 30 mins - 6 hours

Malaise, nausea, severe vomiting

Possible iv. emergency rehydration required

 

Botulism

Clostridium from poorly  canned or bottled food

Usual picture followed by neuromuscular paralysis from the head down including swallowing and respiration

Incubation 24 - 48 hours, Consider antitoxin or polyvalent antiserum

 

 

Parasitic infections

 

Protozoa

Giardia, other amoeba, amoebic dysentery

 

Helminths

Among the commonest chronic conditions in humans

Endemic in areas of poor sanitation

Faecal - oral usually

Produce eosinophilia

 

Threadworms

Mebendazole

 

Ascaris

Respiratory features due to larvae migrating through the lungs, Mebendazole

 

Hookworms

Larvae get in through the skin, migrate to the lungs, are swallowed and infect the gut, eggs are excreted with faeces

Treat anaemia, Mebendazole

 

Strongyloides

Similar to hookworm treat with albendazole for 3 days

 

Bannister BA.  Begg NT. Gillespie SH. (1996)  Infectious diseases,  Blackwell Scientific, Oxford