Dear Doctor: My 5-year-old grandson craves lead paint and has used his toothbrush to get at old layers of lead paint in his family’s renovated 1880s home. His development has slowed, and people think he’s autistic. If it’s the lead, what can we do?

Dear Reader: Your question covers several issues. We don’t make diagnoses in this column, so we would just note that the impulse to eat nonfood items -- such soil, chalk, clay or lead paint -- can be a disorder known as pica. The cause of these persistent cravings isn’t known, but pica has been associated with certain nutritional deficiencies, and with certain mental health conditions. The disorder can lead to serious complications, including intestinal blockage, parasitic infection and lead poisoning.

The United States government banned lead-based paints for residential use in 1978, but it remains a hazard in millions of older homes. Lead is a heavy metal that our bodies can’t use. When ingested, it interferes with numerous metabolic processes, including the production of red blood cells, absorption of calcium for bone and tooth development, and the proper functioning of the liver, kidneys, blood vessels, immune system, nervous system and the brain.

Lead is particularly harmful to the developing bodies and brains of babies, children and adolescents. In high amounts, it can be fatal. Even low levels of lead have been linked to impaired or delayed physical development, low IQ, learning disabilities, and emotional and behavioral problems.

Lead is a cumulative toxicant, which means it builds up in the body over time. As a result, symptoms of lead poisoning can take months or even years to appear. These include loss of appetite, abdominal pain, nausea and vomiting, chronic constipation, hearing loss, problems with vision, persistent fatigue, weight loss, tremors or seizures, irritability and the developmental delay that you report in your grandson.

Since you know your grandson has been eating old paint, it’s important to learn his blood levels of lead as soon as possible. Your family doctor can do this with a simple blood test. Blood levels of lead are measured in micrograms per deciliter, or mcg/dL. Levels as low as 5 mcg/dL are considered potentially unsafe and call for continued screening. It’s also crucial to find and eliminate all potential sources of lead in his environment. In older homes, deteriorating lead-based paint not only chips and flakes, it gives off contaminated dust that is easily inhaled.

In severe cases of lead poisoning, chelation therapy may be recommended. Although it can lower the levels of lead in the blood and soft tissues, it has not been shown to reverse the existing effects of lead poisoning. In this treatment, the child is given a medication that binds to the lead in the blood and soft tissues. It then forms a compound that can be excreted in the urine. Depending on the type of medication used, chelation therapy may be delivered orally or via an injection. Side effects can include headache, nausea or vomiting, and discomfort at the injection site. Chelation therapy should always be carried out under medical supervision, and only with prescription drugs.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: My brother-in-law thought he had the flu, but it turned out to be Guillain-Barre syndrome. He’s now in his fifth month of an intense recovery. What can you tell me about the disease?

Dear Reader: Guillain-Barre syndrome is a rare disorder that affects about 1 in 100,000 people each year. It’s an autoimmune disease, which means the immune system goes a bit haywire. It mistakes cells within your body as threatening invaders and sets out to destroy them. In Guillain-Barre, the immune system attacks the peripheral nervous system, which encompasses all of the nerves in the body other than the brain and spinal cord. Infection with certain viruses and bacteria is a known trigger of Guillain-Barre, and is responsible for up to two-thirds of all cases.

Damage to the nerves results in weakness and exhaustion, often accompanied by tingling or pinprick sensations in the extremities. In the early stages of Guillain-Barre, people experience a loss of coordination that can impair balance, movement, speech, swallowing, vision and bladder control. These initial symptoms, along with possible abnormal blood pressure, both high and low, evolve over the course of the first few weeks. Progressive muscle weakness affects both sides of the body and occurs rapidly, often within hours or days. Severe cases of Guillain-Barre syndrome affect the patient’s ability to breathe and result in near-complete paralysis.

Diagnosis relies largely on a person’s symptoms. However, blood tests to measure red blood cells, white blood cells, platelets and hemoglobin, and metabolic panels to determine levels of electrolytes, blood sugar, total proteins and metabolic waste products, may be used to rule out other conditions. Guillain-Barre can cause certain changes to spinal fluid, so a lumbar puncture, also known as a spinal tap, may be ordered. Tests to measure nerve function can also be useful.

There is no known cure, so treatment consists of addressing existing symptoms, which is known as supportive care. This includes blood therapies such as plasma exchange, or plasmapheresis, which “cleans” the blood, or immunoglobulin therapy, which uses antibodies to try to calm the immune system. Patients often experience significant pain, which can be eased with medication. Since prolonged inactivity can lead to blood clots, compression garments and blood thinners are prescribed often. In serious cases, when swallowing or breathing are compromised, a feeding tube or a ventilator may be needed.

Most patients recover completely. However, as in the case of your brother-in-law, it’s often a gradual process. A lucky few are up and about in just a few months, but the majority of patients take about a year to fully recuperate. It’s also possible for recovery to take several years, and for patients to experience ongoing neurological issues.

Rehabilitative care includes physical, speech and occupational therapy. It can be a tough road back to good health, and many patients and their caregivers find a support group to be helpful. You can find more information at the Guillain-Barre Syndrome Foundation’s web site at gbs-cidp.org.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I was a runner in college, but I stopped running after marriage and kids and work. I’m 62 now, and everyone says that if I resume running I’ll get hurt because I’m too old. What do you think?

Dear Reader: We believe it’s never too late to begin exercising and, with certain important caveats, this includes running.

Studies show that running offers a range of benefits to both physical and mental health. These include improvements to cardiovascular function, strength, endurance and bone health, as well as mood and cognition. An analysis of running studies conducted by British researchers published last year found that running as little as once a week was associated with increased longevity. A similar study published in 2017 found that runners reduced their risk of premature death by up to 40%. Several studies have associated running with an increase in metabolic markers associated with bone formation.

This potentially good news matters only if your approach to running matches your age and your fitness level. That includes taking into account muscle strength, balance, range of motion, heart and lung function, and any chronic health conditions you may have. Even if you are in great shape, your running life will be different today from how it was in your 20s. Based on your age, you’ll need to adjust your frequency, speed, intensity and mileage.

Since osteoporosis is a risk for post-menopausal women, and running is a high-impact activity, we believe it’s important get a bone density test. It’s a quick and painless scan that assesses bone health and can reveal any potential problems. It can also be a predictor of future injuries.

Also, please check with your health care provider before you get back to running. They can be a great resource to keep you strong and healthy, and to help track your progress. They can also make sure you’re being safe while getting back into running.

Do not try to do too much too soon. You’ve heard this before, but it really is important to ease in to your new activity. The most common running injuries, such as shin splints, stress fractures and Achilles tendon pain, arise from overuse. It’s tempting to set goals in terms of miles, but we recommend you think in terms of minutes. Begin by interspersing two or three minutes of gentle running (people used to call it jogging) with five or six minutes of running. Take a moment between cycles to stretch your quads and hamstrings, check your posture and control your breath. Give yourself a few months to gradually build up to a regular running schedule. Make sure to include strength and resistance training in your weekly exercise rotation, which will help prevent overuse injuries. Finally, finishing with gentle leg, hip and torso stretches will help your body recover and get you ready for your next run.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)