Gastroenteritis

a.k.a I had a dodgy kebab last night and now I’m vomiting lots.


Gastroenteritis

Definition: acute inflammation of the lining of the GI tract, manifested by nausea, vomiting, diarrhoea and abdominal discomfort.

Aetiology/ risk factors:

-Viruses, bacteria, protozoa or toxins contained in contaminated food

Commonly contaminated food, includes: improperly cooked meats (S.aureus, C.perfingens), old rice (S.aureus, B.cereus), eggs and poultry (Salmonella), milk and cheeses (Listeria, Campylobacter), canned foods (botulism).

Risk factors: HIV/immunosuppression, Proton Pump Inhibitors, recent antibiotic use, food poisoning outbreaks, travel, diet change, ill contacts

Viral rotavirus, adenovirus, calcivirus, Norwalk virus

Bacterial Campylobacter jejuni, E.coli (esp. 0157), Salmonella, Shigella, Vibrio cholerae, Listeria, Yersinia enterocolitica

Protozoal Entamoeba histolytica, Cryptosporidium parvum, Giardia lamblia

Toxinsfrom Staphylococcus aurea, Clostridium botulinum, Clostridium perfringens, Bacillus cereus, mushrooms, heavy metals, seafood

Epidemiology: very common

Symptoms:

-sudden onset nausea, vomiting, anorexia

-diarrhoea (bloody or watery)

Bloody diarrhoea (dysentery) = CHESS

-Campylobacter, Haemorrhagic E.coli, Entamoeba histolytica, Shigella, Salmonella 

Image result for harry potter chess

(Don’t know how I lasted this long without a HP insert)

 

Explosive diarrhoea = e.g. Cholera, Giardia, Yersinia, Rotavirus

-abdominal pain or discomfort

-fever, malaise

-Botulinum: paralysis

-Mushrooms: fits, renal or liver failure

Signs:

-diffuse abdominal tenderness

-abdominal distension

-bowel sounds often increased

Severe:

-pyrexia

-dehydration (reduced skin turgor, dry mucosal membrane, prolonged capillary refill)

-hypotension

-peripheral shutdown- shock (cold peripheries, tachycardia)

Investigations:

Bloods: FBC (raised WCC, eosinophilia if parasites), ESR/CRP raised

               Blood culture- identification of organism if bacteraemia present

               U&Es- dehydration, electrolyte imbalances e.g. hypokalaemia

Stool: mild gastroenteritis, with no systemic illness (i.e. fever >39ºC, dysentery > 2wks) or special circumstances such as food poisoning outbreaks, immunocompromise, recent antibiotic use or recent travel, do not need stool cultures.

Microscopy for inflammatory cells, parasites, oocysts (baby parasites), culture (bacteria), electron microscopy (viruses), toxin analysis (C.diff toxin).

AXR/USS- exclude other causes of abdominal pain

Sigmoidoscopy- not needed, unless you need to exclude inflammatory bowel disease

Management:

Prevention:

-Food handlers should avoid work until stool sample negative

-Hospital outbreaks need to be carefully managed e.g. wards may need closing

-In hospitals, good infection control measures are necessary.

 

Treatment:

-admit to hospital if there is systemic illness: fever >39ºC, dysentery > 2wks

-bed rest

-fluid and electrolyte replacement with oral rehydration solution

-IV rehydration may be needed if severe vomiting (0.9% saline + 20mmol K+/L IV infusion)

-Antibiotics only if severe or the infective agent has been identified on stool culture (e.g. Ciprofloxacin, a fluoroquinolone, for Salmonella, Shigella, Campylobacter; Metronidazole for Giardia).

Botulism- botulinum antitoxin IM, manage in ITU

Complications:

-dehydration

-electrolyte imbalances

-pre-renal failure (due to volume depletion)

-sepsis and shock (particularly Salmonella & Shigella)

-Haemolytic Uraemic Syndrome, associated with toxins from E.coli 0157 (= haemolysis + thrombocytopenia + renal failure)

-Guillan-Barré Syndrome, weeks after recovery from Campylobacter gastroenteritis

-Respiratory muscle weakness or paralysis, with botulism

Prognosis: Generally good, as majority of cases are self-limiting.

References: Rapid Medicine, Cheese & Onion
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s