June 23, 2020 // Perspective
It was a zebra, not a horse
This patient of mine was a huge man. He was 6-foot-4 and weighed 290 pounds. He did not look at all overweight. He was just big. He had significant coronary artery disease, which in my practice of cardiology is the most common heart condition we see as clinicians. He unfortunately had sustained significant heart damage from a heart attack and was at risk for life-threatening arrhythmias.
We recommended an implantable cardioverter defibrillator to protect him from sudden death. I saw him every six months for over a decade, and we became very close. I recall that when we shook hands, my hand would disappear into these large thick rough working-man hands — not wimpy physician hands like mine. I was sure he could crush every bone in my body if he was so inclined. But as it turned out, he was one of the most gentle human beings I have ever met. He was a nondenominational Christian and worshiped in a small church. He was always soft-spoken and he never seemed to be in any rush. He was a good man.
One time, he came in a little early for his six-month visit to tell me he felt poorly. He had unexplained weight loss, muscle aches and was profoundly fatigued. I was concerned that his heart was deteriorating, so I ordered an echocardiogram to reassess his heart function. It turned out that his left ventricle was actually working better than on the previous test. I also saw no answers on the echo.
He returned to see me several weeks later to tell me he continued to feel awful. Now he reported night sweats and intermittent fever. I was convinced he had a serious infection and admitted him to the hospital for a more rapid and intense work-up. Blood work also suggested an infectious etiology. I thought there would be answers on the pending blood cultures, but when they came back negative (normal) I was perplexed. His symptoms were all compatible with subacute bacterial endocarditis or a heart valve infection.
The next step then was a transesophageal echocardiogram, which is much more sensitive in diagnosing SBE. We can see the heart valves amazingly well if we go inside the esophagus to image the heart with ultrasound. What we look for is vegetations on the valves. These vegetations look like ribbons tied onto the valve’s surface flopping around randomly as the valve opens and closes. The vegetations are caused by the bacterial infection on the valve.
His valves were clean, but what we saw instead was lots of vegetations attached to the ICD wires. He had a bacterial infection involving the ICD wires.
If this indeed was the diagnosis, then we almost always would have positive blood cultures — bacteria growing out of the blood. I ordered more blood cultures and there was no growth again. I was stumped. It was time to call in reinforcements.
We asked our infectious disease physicians to consult. They ordered more blood cultures, which were negative again. They also sent off all kinds of blood tests for rare infectious etiologies. About two weeks later, I received a call from one of my infectious disease colleagues. She asked me if my man liked cats. I had no clue where she was going with this: She then told me that the titers came back positive for Bartonella henselae, the bacteria that causes cat-scratch fever! And, yes, he had several cats at home that on multiple occasions had scratched him on the legs and even sometimes had drawn blood. The mystery was solved.
He was started on antibiotics that kill the Bartonella bacteria, but this would not be successful unless we removed his ICD and the infected wires in his heart, which is a very high-risk procedure. The wires become scarred into place after being in place just a few months, and my man had them in for years. If you try to pull the wires out they can rupture the heart. Highly trained interventional cardiologists need to use specialized equipment to laser-cut the wires right at the inside surface of the heart to remove them. Thankfully, with lots of prayers and one of my skilled partners, the wires and ICD were removed. After six weeks of antibiotics he was cured and back to feeling well.
Cat-scratch fever can occur after a scratch or bite from a cat if it is infected with Bartonella. Young cats and cats with fleas are the most likely carriers. The cat’s fleas are infected too, and therefore flea bites can also cause the infection. The majority of cases are in children and are manifested by fever and localized tender lymph nodes. If scratched on the arm, for example, the painful and enlarged lymph nodes would be found in the axilla, or armpit. This infection can occasionally also enter the blood in children and invade the liver, spleen, eyes or even the brain, causing encephalitis. Cat-scratch fever is the third most common cause of a FUO (Fever of Unknown Origin) in children. Remember this if you are a cat family and one of your children is sick with fever for unknown reasons.
Adults can present just like children with this disease. My patient had a very rare presentation of cat-scratch fever — bacterial endocarditis. The bacteria (Bartonella) usually cannot be successfully isolated in the blood cultures that we commonly order in the hospital setting, and that is why we did not figure out the diagnosis earlier.
In medical school we are taught to think in terms of differential diagnosis. This means you consider common diseases in your patients first before going down the list to the uncommon ones and then finally consider the rare disease processes. There are always at least one or two professors in every medical school that use the following quote to teach their students: “When you hear hoof beats, think of horses, not zebras.” In this case, we were looking for a zebra!
When you study Scripture there usually is a general message to be taken away from the reading. Don’t forget that sometimes, hidden in Scripture, are messages meant just for you, messages that may give you guidance on exactly what you need for that day. Maybe it’s your zebra.
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