The hunt for diagnosis can be interesting
Joseph, a 47-year-old Michigander known to everyone simply as ‘Joe the Hunter’ arrived in the emergency room on a cloudy January day. He told Dr. V.: “Something ain’t right, my stomach hurts, my ‘number 2’ is running like water, and my head feels light as if I’m going to faint.”
Dr. V. also noticed a swollen right eye, and a rash that was evenly spread along Joe’s entire body. Dr. V. paged through the books of knowledge etched in her mind through years of study. She was searching in the drawers of her mind for similar cases she had seen. She was hunting for a precise diagnosis. Making the right diagnosis, she knew, was the key to the appropriate treatment. And she didn’t have much time, because Joe’s heart was starting to beat rapidly, at 134 beats per minute, his breath quickened, and his blood pressure rapidly fell. These were the ominous signs of a developing shock. Do nothing, she realized, and the patient would surely die.
In cases like this, when a call to action becomes urgent, and the exact cause for a patient’s condition cannot be determined fast enough, doctors tend to think in wide categories. Dr. V. thought that the most probable causes for Joe’s rapidly deteriorating condition was either an infection causing a septic shock, or a severe allergic reaction called anaphylaxis. She ordered IV fluids to fight the falling blood pressure, antibiotics to combat a possible infection, epinephrine to counteract a possible allergic reaction, and prednisone to stabilize the immune response.
After all that, Joe’s condition stabilized. His blood pressure returned to normal. His abdominal pain resolved. His rash abated. It was time for celebration, or was it? For the cause for his rapid health deterioration was still in question. He remained in the hospital for further observation.
On day 4 of his hospitalization, Joe picked spare ribs from the cafeteria’s menu. The ribs were delicious, and he devoured them at once. Several hours later, though, his symptoms returned with vengeance: chest tightness, pounding heart rate, shortness of breath, and the resurgence of his skin rash. A single shot of epinephrine — a medication used to relieve severe allergic reaction and anaphylactic shock — put a quick end to this second attack.
As time progresses the true nature of a disease reveals itself. One clue adds to another, and the puzzle solves itself. An astute doctor can hasten the process by asking the right questions. That same day, Dr. V. Asked Joe: Did you eat meat just before the attack that brought you to the hospital?
Joe the Hunter told Dr. V. that he was on a deer-hunting trip in southeast Michigan on the days that preceded the first attack. “And, Yes, I did have some excellent venison on that trip,” he said. Dr. V. felt that the all the different clues in Joe’s story can finally led to one conclusive solution.
Every disease deserves a named diagnosis, and Joe’s was: Alpha-gal Syndrome, which is a type of food allergy to red meat. The story of the disease sounds as if it were taken from a deranged fantasy book, but nevertheless, it was the best explanation for Joe’s predicament: Joe was hunting deer in Southeast Michigan where the lone-star tick is prevalent (the syndrome is associated with other species of ticks in varied locations in Asia, Australia, Europe, and the USA). The tick had previously bitten another mammal — a deer, a horse, perhaps a dog — thereby consuming and retaining a sugar molecule called alpha-gal. This particular tick then bit
Joe and transferred the alpha-gal molecule directly into his blood. This was a new route in which alpha-gal was introduced into Joe’s body–instead of through the digestive system, the molecule was injected into his bloodstream. Joe’s immune system responded by “categorizing” the alpha-gal molecule as a foreign, dangerous substance. From that moment on, Joe’s immune
system would react, or, more precisely, overreact to any meat product containing the alpha gal, be it beef, pork, lamb, or venison.
This immune response is mediated by specialized cells of the immune system called mast cells and by antibodies called immunoglobulin E. The immune response may be dramatic, and its timing is telling — the symptoms typically appear 6-8 hours after ingestion of meat products.
On a hunting trip, just as when searching for the correct diagnosis, timing is everything. Miss the moment of clear vision of your target, and you return home empty handed. Joe has not eaten meat since. His symptoms have never reappeared.
This story is based on a true clinical case as described in the New England Journal of Medicine in February 2021.