Post-polio syndrome (PPS) is a disorder of the nerves and muscles that happens in some people many years after they have had polio. PPS may cause new muscle weakness that gets worse over time, pain in the muscles and joints, and tiredness.

Polymyalgia rheumatica (PMR) is an inflammatory condition that can cause aching and stiffness. It tends to affect the neck, shoulders, and hips. The aching and stiffness are usually worse in the morning.

A pilon fracture is a type of break of the shinbone (tibia) that happens near the ankle. Most of the time, it involves breaks in both the tibia and fibula of the lower leg. The lower ends of these bones make up part of the ankle.

Pericardial effusion is the buildup of extra fluid in the space around the heart. If too much fluid builds up, it can put pressure on the heart. This can prevent it from pumping normally.

In parotid duct obstruction, part of your parotid duct becomes blocked. As a result, saliva can't flow normally from your parotid gland into your mouth.

Neuronal and mixed neuronal-glial tumors are a group of rare tumors that occur in the brain or spinal cord.

Prion diseases comprise several conditions. A prion is a type of protein that can trigger normal proteins in the brain to fold abnormally. Prion diseases can affect both humans and animals and are sometimes transmitted to humans by infected meat products. The most common form of prion disease that affects humans is Creutzfeldt-Jakob disease (CJD).

Neurogenic bowel is the loss of normal bowel function. It’s caused by a nerve problem. Here's what you need to know about this condition.

Nasal polyps are abnormal, soft, swollen, sac-like growths of inflamed tissue. They line the inside of your nose or your sinuses.

Mitral valve regurgitation is when the mitral valve in the heart is leaky. Read on to learn details about this condition, including causes, risk factors, symptoms, diagnosis, and treatment.