Rural Notes 14

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I have been implored by my colleagues to devote this week’s piece to a topical issue we have been experiencing of late, and warn the county’s dog owners of a recent spate of life threatening illness which has struck in recent weeks. Since the better weather arrived, we have been presented with a dozen cases of gut impaction following ingestion of seaweed. In every case the unfortunate owners have brought their poor dog in to one of our surgeries following an incredibly rapid deterioration from robust health to death’s door within the space of a few hours.

With one exception, the dog involved has not deviated from its normal routine, which involves daily walks along one of our beaches. Beaches along the coast, from Dunbar to Portobello have been implicated, suggesting the problem is likely to be spread far and beyond our own county boundaries.

In all cases, the first signs are characteristic of any upset tummy, including vomiting, diarrhoea and loss of appetite, but this quickly progresses to lethargy, depression and weakness with shaking or trembling at the slightest effort to move. By the time that even the initial vomiting or diarrhoea has started (and that the owners have a symptom displayed which they might notice), the patient is already in a perilous medical condition with dehydration and circulatory shock usually present.

The digestive tract is a magnificent example of nature’s marvels. It is the mechanism by which the higher living organisms nourish themselves; foodstuffs are eaten and end up contained within this organ. However, they need to be digested and then absorbed through the gut wall in order for the body to utilise the nutrients contained within them. The process of digestion involves some very powerful acids, some potent enzymes and some very aggressive and dangerous bacteria. These digestive tools enable the body to break down all manner of materials, but it is imperative that these processes are contained within the long tube which is the gut, and not be able to break free and enter the body itself- which with impunity and disastrous consequences they would start to digest.

So, the digestive tract fulfils two complex roles of breaking down foodtsuffs to their basic building blocks, and of containing this process to the confines of a tube which runs through the body, but doesn’t ever freely interact with it.

The Achilles heel of the complicated digestive process is that if something goes wrong, it does so quickly and gravely. Any imbalance of normal function can compromise the integrity of the whole organ and can give access to the whole body by the dangerous digestive processes. Every safeguard the intestine has can fail and the consequences include acute peritonitis with swiftly tragic consequences.

In the case of the seaweed ingestions presented recently, the major problem has been that parts of the stalks of the plants have been swallowed and have become stuck in the intestine. As the tide recedes and leaves the weed exposed on the sand, it very quickly dehydrates and shrinks. Leaves, as thick as this newspaper, become as thin as a single page, and stems as wide as an arm can appear like a child’s finger. Unfortunately, they tend to be swallowed without adequate chewing, and once in the moist environment of the gut, they respond by swelling and becoming lodged. In short order, the intestinal wall suffers first bruising and then loses its blood supply as the swelling contents exert a tourniquet effect and cut off the blood supply. Inevitably, the wall becomes damaged and sooner rather than later will burst, releasing the digestive juices into the body.

From our perspective, it can be extremely taxing to accurately diagnose the problem. In the early stages, the seaweed may not yet have absorbed enough fluid and become swollen enough for easy identification as a blockage. X-rays are rarely very helpful; as opposed to things like swallowed bones or golf balls, plant material doesn’t really show up on X-rays. In most cases, the diagnosis is made based on the history, which involves recent beach walks, usually off the lead. If caught early, surgery to remove the obstruction can be curative, but this needs to be timely and sadly about a third of affected patients will not survive.

Whilst it is clear that both rapid assessment of suspected cases and rapid surgery where appropriate maximises the chances of a positive outcome, there is still a lot of work to do after the operation, and our nurses are invariably exhausted after delivering round the clock care to their patients for a number of days in early recovery.

What is not so clear is why we seem to be experiencing a current rise in cases. The usual suspects are common inhabitants of our coastline all year round.  Kelp, Mayweed, Bladderwrack and Sea Oak are all implicated. It appears likely that rising sea temperatures encourage their growth, and hence their abundance and availability. It is also the case that warmer drier air conditions means that any weed uncovered between high tides is more likely to dehydrate, thus meaning they are likely to swell to a disproportionate size once rehydrated after being eaten. It also appears likely that summer, with more daylight, enhances their ability to make and store nutrition, and this may make them more tasty to dogs. Ironically, many seaweeds are highly nutritious and have been used as diet staples across many cultures. Many boast medicinal qualities, and a host of seaweed based dietary supplements adorn health shop shelves. All of these however are processed in some way, and not the raw material found by the shore.

"In recent years there has been an alarming incidence of seaweed poisoning in dogs..."

We should consider ourselves lucky in one sense though. In recent years there has been an alarming incidence of seaweed poisoning in dogs, centred on the East Anglian coastline. A species of seaweed known as Sea Chervil appeared to develop the capacity to store toxins and without even becoming stuck, carried sufficient toxin to kill dogs who ate it. On just 2 beaches in a short timescale, seven fatalities were reported from dogs which had eaten some of the weed. It is thought that some plants can acquire toxins present locally and concentrate them within their tissue whilst themselves showing no signs of ill health. The sea has almost limitless exposure to pollution and one of the major worries that climate change oceanologists have relates to the long term implications this may have in some of our worlds dirtier waterways.

I have no desire to sound like a killjoy. One of life’s purest pleasures is walking a dog off its lead, along a quiet beach and watching him or her bound across the sand and play with the waves. It might be prudent however to remember that beached seaweed and dogs do not mix, and if your pet takes any undue interest in some harmless looking fronds you should be immediately intervene and drag them off to safer sands.

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Glen Watson
Partner at Links Vet Group