Why did this teen gain 12 pounds in a week? | Medical Mystery

A previously healthy 17-year-old male came to the emergency department after putting on 12 pounds over one week. The patient was a wrestler in peak season who was weighing himself daily to make sure he stayed in his wrestling class. On top of the weight gain, he also had chills, fatigue, nasal congestion, and cough. The morning they took their son to the hospital, his parents noticed that his face was puffy.

The nurse checked his vital signs and found he had a fever and high blood pressure of 160/100, higher than the normal for a teenage male, which is no more than 120/80.

The boy appeared very ill to the physician who examined him and noticed his body appeared swollen everywhere, including both legs. The physician ordered blood tests and a chest x-ray, and admitted him to the hospital for further evaluation.

What caused this patient’s symptoms?

Rapid weight gain can happen for many reasons, and doctors ask questions and do tests to figure out the cause. One reason could be that the body is holding onto extra fluid, which can happen with heart problems, liver disease, or kidney problems.

Heart problems such as congestive heart failure happen when the heart cannot properly pump blood through the body, leading the heart to become enlarged. This causes fluid to leak out of the blood vessels and into the tissues, causing swelling. Congestive heart failure is more common in older adults than it is in children and teenagers, unless the child was born with a congenital heart defect. The chest x-ray showed this patient’s heart was a normal size. However, it also showed signs of an infection of the lungs, or pneumonia.

Liver disease can also lead to rapid weight gain due to fluid retention. A healthy liver makes a protein called albumin, which helps keep the fluid in blood vessels. When the liver cannot make this protein, the fluid leaks out, causing tissues to swell. Sometimes liver failure causes high pressure in the vessels that supply the liver with blood, and that also can cause the fluid to leak out of the vessels. This can lead to ascites, or fluid buildup in the belly.

Liver disease can have many different causes.

This patient had taken acetaminophen (Tylenol) for a few days, which could lead to liver damage, but blood tests showed that wasn’t the cause. Autoimmune diseases like systemic lupus erythematosus or autoimmune hepatitis can cause liver disease but his autoimmune blood tests were normal. Overall, the patient’s blood tests indicated liver function was normal, so a liver problem was less likely the cause.

Next, we turned to the possibility of kidney problems, which can cause fluid retention as well. The job of the kidneys is to filter the blood and remove excess fluid and waste products from the body. When the kidneys are not working right, fluid stays in the body. Kidney issues can be caused by multiple urinary tract infections, structural problems of the kidney which are often inherited, or damage to the filtering system. This damage is called glomerulonephritis and can be caused by multiple types of infections, medications, or immune damage to the kidneys.

A test of the patient’s urine showed the presence of blood and protein, and his blood tests showed an elevated blood urea nitrogen (BUN) level, as well as elevated creatinine level. These findings indicated that a kidney problem was most likely the cause of his rapid weight gain. He said he had no history of UTIs and was not using medications or supplements that could have damaged his kidneys. Further tests would be needed to find out exactly what was going on.

He received extra oxygen and antibiotics to treat the lung infection. After a few days he started feeling better and didn’t need the oxygen anymore. The doctors also took a biopsy from his kidney which showed temporary inflammation without permanent scarring.

The final diagnosis was glomerulonephritis related to his pneumonia. During this infection, his body was producing antibodies to fight off the bacteria. Some of these antibodies accidentally attacked his kidneys and caused inflammation and temporary damage. His kidneys returned to normal soon after the infection went away.

Our advice: Teenagers who gain weight very rapidly should see their doctor to potentially be screened for heart, liver, and kidney problems.

Rebecca Petlansky is a second-year pediatric resident and Hayley Goldner is a pediatrician in the adolescent medicine department at Nemours Children’s Hospital, Delaware.