Dysentery
Dysentery is the name given to a gut infection that inflames the large bowel and puts blood and mucus into the stool.
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Medicines commonly prescribed for Dysentery
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: ORAL SOLUTION/SUSPENSION, 500 mgActive substance: azithromycinManufacturer: Tarbis Farma S.L.Prescription requiredDosage form: TABLET, 500 mgActive substance: azithromycinManufacturer: Mabo Farma S.A.Prescription requiredDosage form: TABLET, 100 mgActive substance: doxycyclineManufacturer: Laboratorios Normon S.A.Prescription required
Dysentery is the name given to a gut infection that inflames the large bowel and puts blood and mucus into the stool. Strictly speaking it is not a single disease but a description of a picture, and more than one organism can produce it. Which one is responsible decides how long recovery takes and whether antibiotics are needed at all. Most adults are over it within a week. But blood in the stool is precisely the sign that is not sat out at home: it always gets shown to a doctor, and in a child it gets shown the same day.
What it looks like
It usually starts abruptly, often a day or two after a doubtful meal or contact with someone who was ill. At first the stool is simply loose and watery, and within a day streaks of blood and cloudy mucus appear in it. Alongside that come:
- cramping pain in the abdomen, more on the left and low down, easing briefly after a trip to the toilet;
- frequent exhausting urges that produce almost nothing, known as tenesmus;
- fever, shivering, aching limbs and flatness;
- nausea and sometimes vomiting;
- no appetite and obvious weakness by the end of the first day.
One detail helps separate dysentery from other gut infections: each stool is small, but the trips to the toilet are numerous, ten, twenty or more in a day. In watery diarrhoea it is the other way round, litres are lost over a handful of episodes but there is no blood. The mechanisms differ: there the bowel is pouring out water, here it is inflamed and damaged on the inside.
The other side of the question is worth remembering too. Blood in the stool does not always mean infection. An anal fissure, haemorrhoids, inflammatory bowel disease and, in an older person, a tumour can all look similar. If the diarrhoea has passed and the blood has stayed, or if bleeding returns in waves over months, a microbe is almost certainly not the answer and the investigation needs to go a different way.
Where it comes from
There are several culprits and they behave differently.
- Shigella, the classic bacterial dysentery. It is remarkably infectious: swallowing a very small number of organisms is enough, which is why it moves so easily through a household or a nursery.
- Certain groups of Escherichia coli, including the ones that make Shiga toxin. They are linked to outbreaks through undercooked mince, unpasteurised milk, poorly washed salad leaves and contact with farm animals.
- Campylobacter and salmonella, most often after undercooked poultry or eggs. Blood does not always appear, but the pain can be severe.
- The dysentery amoeba, which is not a bacterium but a protozoan. It belongs to tropical and subtropical regions, builds up more slowly over one or two weeks, often runs with little fever and produces diarrhoea that comes and goes. It is the one to keep in mind after a trip to a hot country.
The route in is always the same, the mouth, by way of anything that has been in contact with an ill person's faeces. In practice that means unwashed hands, tap water where sanitation is poor, ice cubes, vegetables and herbs rinsed in that water, shared towels, and oral and anal sex. A person is infectious while the diarrhoea lasts and for a while afterwards, which is why the rest of the household tends to go down a few days after the first case.
When it cannot wait until morning
Call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine the single European number 112 works) or go straight to emergency care if any of the following turns up:
- the amount of blood is large, or the stool is essentially blood;
- there are signs of dehydration: a dry tongue, dizziness on standing, little and very dark urine, and in a child a dry nappy for six to eight hours at a stretch, crying without tears, a sunken fontanelle or unusual drowsiness;
- vomiting prevents even a sip of fluid staying down;
- the abdomen swells and goes hard, the pain becomes constant and severe and the stools have stopped altogether — that is how a dangerous complication behaves, in which the large bowel stretches beyond its limit;
- high fever with confusion, seizures or heavy drowsiness;
- the ill person has a weakened immune system, is pregnant, is elderly, or is a baby under three months.
One thing deserves its own paragraph, and it is the reason a text like this is worth reading at all. A few days after bloody diarrhoea, most often in a pre-school child, haemolytic uraemic syndrome can develop: Shiga toxin destroys red blood cells and injures the kidneys. The warning signs are sudden pallor, unusual sleepiness, puffy eyelids and legs, bruises with no knock behind them and, above all, a child who has almost stopped passing urine just as the diarrhoea is settling. This is treated in hospital only, and time counts for a great deal. Faced with that combination, call an ambulance at once rather than waiting for an appointment.
What the doctor does
The first job is to work out who is responsible. That takes a stool sample, cultured and tested for the DNA of the likely organisms, and if an amoeba is suspected the sample also goes under the microscope or is tested for its antigens. Blood tests show how fierce the inflammatory response is, whether the kidneys have suffered and whether the blood has concentrated from fluid loss. If you have recently come back from a trip, say so and name the destination: the range of possible causes shifts considerably with the place.
Then comes the part that surprises many people: antibiotics are not needed by everyone. Most bacterial dysentery settles on its own, and treatment shortens the illness by little more than a day. More than that, where a Shiga toxin producing Escherichia coli is suspected, antibiotics can raise the risk of exactly the kidney injury described above, so they are not handed out casually before the result is back. The opposite case exists as well: in severe illness, in confirmed shigella infection, in weakened patients and in very young children an antibiotic genuinely is required. Amoebic infection is treated with completely different drugs and in two stages — first the parasite is cleared from the tissue, then a separate medicine clears it from the bowel lumen, because otherwise the illness comes back. All of this is the doctor's decision and cannot be sorted out by reading online.
If dehydration is severe, vomiting cannot be controlled or a complication is suspected, the patient is admitted and fluids are replaced through a drip.
At home the point is not to dry out
While the diarrhoea lasts the body loses water and salts together, and it is the missing salts that produce the weakness, the headache and the light-headedness.
- Buy oral rehydration sachets from the pharmacy and drink the solution steadily in small amounts, a few sips every five to ten minutes. A whole glass at once usually comes back up.
- Fizzy drinks, shop-bought juice and sports drinks do not do this job: there is far too much sugar in them and they make the diarrhoea worse.
- Eat as soon as you feel like it. There is no need to fast or to live on rice and dry toast for weeks, since that only slows the bowel's recovery. Start with ordinary food in small portions.
- Some people tolerate dairy less well for a couple of weeks after a gut infection; if it brings bloating, simply set it aside for a while. Breastfeeding, by contrast, carries on without a break.
- Medicines that stop diarrhoea are not taken when there is blood in the stool. They hold the organism and its toxins inside and raise the risk of complications.
- Alcohol, coffee and very fatty food are sensibly left until afterwards.
- Ask a doctor or pharmacist about paracetamol and other painkillers, particularly if you already take something regularly.
A week is the usual course. Loose stools and a rumbling gut can carry on for another ten days after everything else has passed, and that is nothing to worry about. What does mean going back is no improvement at all after a week, or blood reappearing after a few good days.
Keeping the rest of the household well
Dysentery travels through a home quickly, and here the plain measures work better than any medicine.
- Wash hands with soap and water for at least twenty seconds, after the toilet, after a nappy change and before cooking and eating. Alcohol gel performs less well against gut infections: it does not wash particles away, and some of these organisms shrug alcohol off.
- Give the ill person a towel of their own.
- Wash soiled clothes, towels and bedding separately and hot.
- Wipe the toilet seat, the flush handle, taps, light switches and door handles every day.
- Do not cook for other people until two days have passed since the last loose stool.
- Stay out of swimming pools for two weeks after recovery: chlorine does not deal with everything.
- A child stays at home and away from nursery or school until forty-eight hours after the last episode.
- Sex is best avoided during the illness, and barrier protection for oral and anal contact is worth keeping up for some time afterwards.
If you are travelling
Where clean water is difficult, the risk of a gut infection is high, and almost all of it turns on a few simple habits.
- Drink bottled water with the seal intact, or boiled water, and clean your teeth with the same.
- Remember that the ice in a drink is that same tap water.
- Choose fruit and vegetables that peel, and peel them yourself; skip salads and raw herbs in doubtful places.
- Eat hot, freshly cooked food; anything that has been sitting on a counter or in the sun is best walked past.
- Ice cream, homemade dairy puddings and unpasteurised cheese in hot weather are a common source of trouble.
- Pack rehydration sachets: they will earn their place far more often than a full first aid kit.
And always tell the doctor about the trip if bloody diarrhoea started on the road or in the first weeks after coming back, even if by then you are home and feeling reasonably well.
Online consultation
A remote appointment settles the main question well: whether this is an ordinary gut infection that can finish healing at home, or a situation that needs examination and tests today. The doctor will go through how it started, what you ate and where you were, how many stools a day there are and how much fluid is actually going in, will weigh up the risk of dehydration and will explain which stool test is worth doing and how to collect the sample properly. Separately, they will set out which signs to watch for in a child over the coming days and the point at which everything gets dropped in favour of emergency care. The situations in the warning list are not handled remotely: with those, an ambulance is called straight away.
This material is for information only and does not replace medical advice.
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