Home-brewing is a trend that is becoming more and more popular, and unfortunately, so is the occurrence of hops toxicity in dogs. Hops is the plant used in the process of brewing beer, and both the 'raw' or spent hops are toxic. True flowers or dried hops plugs tend to be more toxic than hops pellets (pellets have less residue), while wild hops have been found to be non-toxic. The diagnosis is generally made based on history of having home-brewing supplies as well as seeing hops in vomit.
The mechanism of toxicity is unknown, but may be related to essential oils, resins, phenolic compounds, or nitrogenous constituents within the plant. Many of the substances in hops are degraded or aerosolized during the brewing process, so the exact relationship between substance and toxicity remains unknown.
Clinical signs of toxicity can include agitation, panting, excitement, flatulence, rapid heart rate followed by life-threatening elevations in body temperature. Death has been reported in as little as 6 hours without appropriate treatment. I have seen rectal temperatures greater than 108 F, and these temperatures can be very difficult to control. The high end of normal of a dog’s temperature is 102.5 F, and any temperature above 106 F can lead to an “unwinding” of the body’s proteins as well as permanent brain injury, depending upon the length of time that the elevation in body temperature persists.
Treatment consists of aggressive decontamination measures including induction of vomiting, gastric lavage (“washing out” the stomach under anesthesia), administration of charcoal, and enemas. Active cooling by any means available is extremely important. There are also specific medications that can be given in the hospital to help control the clinical signs.
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Prognosis for survival is generally guarded to poor, and unfortunately, many deaths have been reported. We have had 2 cases of hops toxicity this past year in the ER, and thankfully, both survived with aggressive treatment.
Any breed of dog may be affected, but breeds that are predisposed to malignant hyperthermia (extreme elevation of body temperature for an unknown reason) tend to be more susceptible. These breeds include Greyhounds, Labrador Retrievers, Saint Bernards, Pointers, Dobermans, Border Collies, English Springer Spaniels, and northern breeds.
If you suspect your dog has been exposed to hops, seek veterinary care immediately! This is not something that can be managed at home. Quickly take a rectal temperature, and if it is found to be greater than 105 F, begin active cooling measures—such as dousing your pets body with cool water and wrapping icepacks in towels and placing them over its body—in addition to running the air conditioning in car while on your way to your veterinarian or local emergency clinic. This measure could help save your pets life and give him or her the best chance for survival.