Ask the Doctors: Rabies preventable with vaccine

Dear Doctors: We just heard a story on the news about a man who got bitten by a bat and then died of rabies a few weeks later. We see bats in our area a lot, so we're worried. Why didn't the rabies treatment work? What is rabies, anyway? Dear Reader: You're referring to a case that occurred last August in a community just north of Chicago. An 87-year-old man woke up to find a bat on his neck. The bat, which was captured, tested positive for rabies. Despite urgent warnings that he needed immediate preventive care, the man refused.

Treatment for rabies consists of an initial injection of a medication known as rabies immunoglobulin, which is made up of antibodies against the rabies virus. It is given in the vicinity of the bite to stave off infection. This is followed by a series of four shots given in the arm over the course of two weeks. The medication in these shots teaches the immune system to recognize and fight off rabies infection.

Unfortunately, the man developed symptoms consistent with rabies a month later. These include headache; neck pain; difficulty controlling the motor function of the arms, hands and fingers; difficulty with speech; exhaustion; and numbness.

Rabies is almost always fatal, and the man passed away. However, with the medical care that the man declined, the disease is 100 percent preventable. Once the virus begins to cause symptoms, though, it's too late for the treatment to be effective. That's why, whenever exposure to rabies is suspected, treatment must begin immediately.

Rabies is caused by a virus that attacks the nervous system. It is spread via the saliva of an infected animal, most often through a bite. In other parts of the world, where up to 60,000 people die of rabies each year, dog bites are the most common cause of infection. Here in the United States, thanks to robust veterinary vaccination programs, the disease is most often found in wild animals. This includes raccoons, skunks, foxes and, yes, bats.

Cases of rabies in humans are quite rare in the U.S., with fewer than three reported each year. The death in Illinois was the first in 67 years in that state. This speaks to the efficacy of the treatment, which is received by 30,000 to 60,000 people each year. However, it's still important to practice prevention. At this time, physical contact with saliva from an infected bat is the leading cause of rabies exposure in the U.S. Wildlife experts caution that you should never touch a bat with your bare hands.

If you know or suspect that you've been bitten by a bat, seek immediate medical care. Whenever possible, the bat should be captured and sent to a laboratory for rabies testing. But just because you have bats in your area doesn't mean you're in danger. Wildlife experts say that just a fraction of 1 percent of bats carry rabies. Stay safe by keeping your pets' rabies vaccinations up to date, and when it comes to bats and other wildlife, keep your distance.

Dear Doctors: I inherited my mother's prominent varicose veins, and despite surgery, they are back. My sister recently told me our mother had deep vein thrombosis when she was older. She told me to be careful, and to watch for symptoms. Am I at risk because of my varicose veins?

Dear Reader: Deep vein thrombosis, or DVT, is a serious condition that is considered a medical emergency. It occurs when a blood clot, also known as a thrombus, forms in the veins deep within the body. Although DVT is most common below the knee, it also occurs in the thighs, arms or abdomen. It can be caused by slow or reduced blood flow due to prolonged periods of immobility, increased blood pressure within the vein, increases in blood viscosity or physical damage to the veins themselves. The danger is that if a blood clot breaks free, it can travel to the lungs and cause a blockage, known as a pulmonary embolism. This can be fatal.

Whether due to genetics or a range of health conditions, some people are at increased risk of coagulation, which also plays a role in DVT. Additional risk factors include being obese, being older, living with chronic heart or airway disease, having a recent surgery, living with cancer and smoking.

DVT can be a silent condition. When symptoms do occur, they include a throbbing sensation or a cramping pain, occurring only in one leg, typically below the knee. The area may feel unusually warm, and skin may appear reddened or a darker hue than usual. In some cases, swollen veins may be visible, which feel tender and are hard to the touch.

Varicose veins, by contrast, are surface blood vessels that have become visibly enlarged or misshapen. This occurs due to increased blood pressure that is beyond what the somewhat-fragile one-way valves in the veins can withstand. The result is that the valves allow some of the blood that is headed to the heart to flow backward, which causes it to pool. This gives varicose veins their characteristic dark blue or purplish color and their raised or swollen appearance. Risk factors for developing varicose veins include older age, being overweight, being female, smoking, using oral birth control or hormone replacement, and inactivity. Although not considered a serious medical condition, varicose veins can be uncomfortable, and even painful.

When it comes to your question about varicose veins being a risk factor for deep vein thrombosis, the answer is not yet entirely clear. A study published in the Journal of the American Medical Association in 2018 found a link between having varicose veins and an increased risk of DVT. However, the patients with varicose veins also had a measurably higher incidence of other medical conditions, including respiratory disease, cardiovascular disease and metabolic conditions such as diabetes. This made drawing a direct connection between the varicose veins and DVT somewhat tricky. To ease your mind, it would be a good idea to become familiar with the symptoms of DVT. If any of them should arise, seek immediate medical care.

Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.