Guinea pig chewed an electrical cord: oral burns and the damage that arrives later

Quick answer

An electrical injury looks almost invisible on the day it happens. The work is in the days that follow.

A guinea pig that has bitten through a live cable has an electrical injury, not a heritable condition. Chewing is normal guinea pig behaviour driven by teeth that grow continuously for life, so every guinea pig with floor access to a cable is at risk. Nothing about it is inherited.

The dangerous thing about electrical injury is how harmless it looks in the first hours. The mouth may show only a small pale mark. The animal may seem stunned and then apparently recover. The three things that actually kill a guinea pig after an electrical injury all declare themselves later.

• Cut the power at the wall socket or the consumer unit before you touch the animal or the cable.
• Get veterinary advice the same day even if the guinea pig looks completely normal.
• Watch the breathing for at least 48 hours. Fast, shallow or effortful breathing after an electric shock is an emergency.
• Watch food intake and droppings from the first hour. A guinea pig that stops eating is in a second, separate emergency.
• Expect the mouth injury to get visibly worse around one to three weeks later, not better.

:::danger
Do not touch the guinea pig, the cable, or any wet surface near them until the power is off at the socket or the breaker.

A guinea pig can remain in contact with a live conductor, and current will pass through you if you pick it up. Switch off at the wall, pull the plug by the moulded plug body, or trip the breaker. If you cannot reach the switch, use a dry wooden or plastic object to separate the animal from the cable while standing on something dry.
:::

Decide in 60 seconds

Why an electrical injury behaves differently from a burn

A scald or a heat burn deposits energy on a surface. Electrical injury deposits energy along a path.

Current enters where the animal contacts the conductor, usually the lips, tongue or palate in a guinea pig, and leaves wherever the animal is grounded, usually a foot or the whole underside if it is sitting on a damp or conductive surface. Everything between those two points is in the circuit.

Tissue heats in proportion to its resistance, so nerve, blood vessel and muscle along the path can be cooked while the skin over them looks untouched. That is why an apparently small mouth lesion can sit above a large area of dead tissue.

Voltage matters and it differs by region. Mains supply runs at around 100 to 127 volts in Japan and much of North America, and around 220 to 240 volts across most of Europe, Asia, Africa, Australia and South America. For the same contact resistance, higher voltage drives proportionally more current, so the same chewed cable does more damage in a 230 volt region.

Saliva lowers contact resistance dramatically. A wet mouth on a live conductor is close to the worst case, which is why oral injuries dominate in cord-chewing animals.

Two things happen at the moment of contact that have nothing to do with heat. Current across the chest can throw the heart into an abnormal rhythm, and a sudden massive discharge from the nervous system briefly drives blood pressure inside the lung vessels to a level they are not built for. Both can be survived at the time and both have consequences you will not see for hours.

What the mouth looks like, and how it changes

Lift the lip gently and look at the corners of the mouth, the front of the tongue and the palate. Do not probe, scrub or flush.

Day one.

Look for a pale, greyish, yellow-white or chalky area, most often at the corner where the upper and lower lips meet, on the tip or edge of the tongue, or across the hard palate. It is typically dry rather than bleeding. It may look like a line, matching the shape of the cable.

The lack of blood is not reassurance. Electrical injury coagulates vessels as it destroys them, so the wound seals itself. That sealed dead tissue is called an eschar.

Also check for singed whiskers or fur around the muzzle, which tells you the contact point even if the oral lesion is hidden.

Days two to seven.

The margin between dead and living tissue becomes clearer. The dead area may darken, and swelling of the surrounding lip and face increases as inflammation sets in. Drooling starts, because swallowing hurts. This is when eating stops if pain is not being controlled.

One to three weeks.

The dead tissue separates from the living tissue underneath. This is the stage owners are never warned about. Underneath is an open wound rather than the small mark they saw on day one, and the vessels that were sealed by the original injury can open as the eschar comes away. Bleeding at this stage can be brisk and is a genuine emergency.

Beyond three weeks.

Healing by scar contraction pulls the lip and cheek tissue inward. In a severe case this narrows the mouth opening and interferes with eating and with normal grooming. Where the injury involved the growth region of an incisor, the tooth that grows afterwards can come through misshapen or misaligned, and because guinea pig teeth never stop growing, a malocclusion that starts here becomes a lifelong problem needing repeated dental work.

The three delayed problems that kill

Fluid on the lungs.

The sympathetic surge at the moment of shock raises pressure in the lung capillaries and makes them leak. Fluid collects in the air spaces of a heart and a pair of lungs that were previously healthy. It develops over hours, most often within the first day, and can appear up to two days later.

Watch for an increased breathing rate at rest, effort visible in the flanks or the abdomen, an outstretched neck, blue or grey tinged gums or ears, or any wet, crackly or raspy sound. Guinea pigs are obligate nose breathers, so open-mouth breathing is a very late and very serious sign.

Count breaths while the animal is resting and quiet, at the same time each day, and write the number down. Trend matters more than any single count.

Gut stasis.

This is the one that catches most owners. A guinea pig is a hindgut fermenter whose digestive tract has to keep moving. Pain, stress and reduced food intake all slow it. Once it slows, gas builds, that hurts more, and the animal eats less again.

Signs are fewer droppings, then smaller and drier droppings, then none. The guinea pig sits hunched, is reluctant to move, may grind its teeth, and stops the normal chatter and popcorning.

Pain control is not optional comfort here. It is the treatment that prevents the stasis. A guinea pig with an untreated painful mouth will not eat, no matter how good the hay is.

Heart rhythm disturbance.

Current across the chest can leave the heart beating irregularly for hours after the event. There is nothing you can do about this at home other than get the animal seen, keep it quiet, and avoid handling that increases its heart rate.

The first hour, step by step

Cut the power at the socket or the breaker before touching anything.

Move the guinea pig to a quiet, warm, dimly lit box or carrier lined with a towel. Warmth matters because guinea pigs lose heat fast when shocked and a cold guinea pig deteriorates quickly, but keep any heat source gentle and always leave a cool area the animal can move to.

Do not clean, flush or rinse the mouth. Flushing risks pushing fluid into the airway of an animal that cannot vomit and may have a reduced swallow reflex.

Do not apply cream, ointment, honey, butter, oil, flour, antiseptic or anything else to the mouth. It does not help, it obscures the vet's assessment, and much of it is harmful if swallowed.

Do not offer food or water while the animal is dazed or unsteady. Wait until it is clearly alert and swallowing normally.

Look at the gums with a torch if you can do it without a struggle. Pale, white, grey or blue mucous membranes are a circulation or oxygenation emergency.

Count the breathing rate while the animal is at rest and note it down with the time.

Transport dark, warm and level. Line the carrier with a towel over a thin layer of familiar hay so the smell is right and the surface is not slippery.

Take a photograph of the chewed cable and of any visible mouth lesion, and note the time you found the animal. Take the guinea pig's cage mate with it if it has one, because separating a bonded pair adds stress to both and bond breakdown after a hospital stay is a real problem.

The 24 to 72 hours that follow

The purpose of this window is monitoring, not treatment. Almost everything that goes wrong in it announces itself first in one of three numbers.

Weigh the guinea pig on a kitchen scale at the same time every day. Weight is the most sensitive early indicator of reduced intake that an owner has, because fur hides body condition.

Count droppings, or simply keep the previous day's soiled bedding and compare. A drop in number or size precedes visible illness.

Count resting breaths daily.

Keep offering the animal's usual hay, plus grass and fresh vegetables that carry water. Soft, wet food is easier for a sore mouth. If the vet has provided a recovery formula for syringe feeding, follow their instructions on volume and frequency rather than guessing.

Vitamin C requirement rises during healing because guinea pigs cannot synthesise it and it is needed for collagen formation. Discuss supplementation with the vet rather than dosing from a general-purpose product, and do not rely on vitamin drops in the water bottle, which degrade quickly in light and put the animal off drinking.

What changes the picture

Age.

Young guinea pigs chew more and explore more, and have less physiological reserve. Older guinea pigs may have existing dental or heart disease that the injury unmasks.

Pregnancy.

A pregnant sow that stops eating is at risk of pregnancy toxaemia, which is rapidly fatal. Any pregnant sow involved in an electrical injury is an immediate emergency regardless of how she looks.

Coat type.

Long-coated breeds hide singed fur and facial swelling. Part the coat around the muzzle and jaw and look at the skin.

Living arrangements.

A guinea pig housed with a companion often keeps eating out of competition, which masks a declining appetite. Feed them briefly in separate areas during the monitoring window so you know who ate what.

Where it happened.

If the guinea pig was on a damp surface, a tiled floor or a metal cage base, the current path through the body was longer and more of the animal was in the circuit.

Prevention that actually holds

A cable lying on the floor is live along its whole length whenever it is plugged in, whether or not the appliance is switched on. Turning the lamp off does not make its flex safe.

What never to do

Do not touch the animal before the power is off.

Do not treat a normal-looking guinea pig as uninjured. The dangerous complications are silent at first.

Do not scrub, flush or pick at the mouth lesion at any stage, including when the dead tissue starts to lift.

Do not give leftover antibiotics from another animal. Several antibiotic classes are lethal to guinea pigs because they destroy the gram-positive bacteria the hindgut depends on and allow a fatal overgrowth. Only a vet familiar with the species should choose the drug.

Do not give human painkillers. Several are toxic to small herbivores and the doses are not scalable.

Do not withhold food to "rest" the gut. A guinea pig gut that rests stops.

Do not assume a sealed, dry-looking wound is healing. That appearance is the definition of the injury, not evidence of recovery.

Do not breed away from the problem. There is no heritable component. Selecting animals or bloodlines on this basis achieves nothing and distracts from the only thing that works, which is making cables inaccessible.

When to get help

Get emergency help immediately, out of hours if necessary, for any of these:

Any change in breathing rate, effort, sound or posture at any point in the first 48 hours.

Pale, white, grey or blue gums, ears or feet.

Collapse, unresponsiveness, weakness or a wobbly gait.

No droppings for several hours, or a refusal of hay.

Bleeding from the mouth at any stage, including at the one to three week mark.

Get a same-day appointment for a guinea pig that seems well but was in contact with a live cable, because the point of that visit is the examination and the monitoring plan, not the wound.

What the vet will do.

They will examine the mouth properly, which usually needs sedation to see the back of the oral cavity in a guinea pig. They will listen to the chest for the crackles of pulmonary fluid and check the heart rhythm. They will assess hydration and pain, and provide analgesia, which is the intervention that most directly prevents the fatal complication. Imaging of the chest may be used to confirm or exclude pulmonary oedema. They will plan a recheck for the eschar separation window.

What they will ask you for.

The time it happened or the time you found the animal. Which cable and what it powers, and whether it was plugged in. A photograph of the cable and the mouth. What surface the guinea pig was standing on. The animal's weight before and after. Dropping count. Resting breathing rate with times. Whether it has eaten, and what. Whether it has a companion and whether that animal was also exposed.

Recovery is judged on eating, droppings and weight, not on how the wound looks. A guinea pig eating hay normally is the outcome you are aiming for.

Most guinea pigs that receive prompt pain relief, stay eating and get through the first 48 hours without breathing changes recover well. The long-term issue to watch is the mouth: book the recheck, and keep an eye on tooth alignment for months afterwards, because a tooth damaged at the root will only show itself once it has grown out.