Health A-Z

Clinical Definition Narcolepsy is a chronic neurological disorder that interferes with a person’s sleep-wake cycle. In Our Own Words People who have the sleep disorder, narcolepsy, often fall asleep uncontrollably, even after having adequate sleep. During the day, you may be excessively sleepy and nearly unable to function. Sleep attacks can occur even when narcoleptics…

Clinical Definition Nasal polyps are small growths of inflamed tissue that are noncancerous and can develop on the nasal mucosa or paranasal sinuses. They are associated with prolonged inflammation of the nasal passages or sinuses from conditions such as chronic sinusitis, allergic rhinitis and asthma. If nasal polyps become too large, they can obstruct the…

Clinical Definition Nephrotic syndrome, a collection of symptoms and laboratory findings that indicate renal damage, is marked by heavy protein in the urine, peripheral edema and hypoalbuminemia. Hyperlipidemia and thrombotic disease are also common. In adults, renal or systemic disease such as diabetes may be the cause; in children, minimal change disease is the major…

Clinical Definition A nervous breakdown is technically not a medical term, but is frequently used to describe a feeling of overwhelming anxiety and stress, such that a patient is unable to maintain their previous normal level of functioning. It is commonly considered apart from any psychiatric diagnosis such as bipolar disorder, and individuals suffering from…

Clinical Definition Neuropathy, also called peripheral neuropathy, describes damage to the peripheral nervous system—a network of nerves that connects the brain and spinal cord to the rest of the body. Neuropathy may be acquired from trauma, infection or systemic disease, or may be caused by medications, blood vessel problems or alcoholism. Charcot-Marie-Tooth disease is the…

Clinical Definition Nicotine withdrawal occurs when someone dependent on nicotine ceases tobacco use. Nicotine is possibly as addictive as heroin, cocaine or alcohol. Withdrawal symptoms may include irritability, anxiety, concentration difficulties, insomnia and increased appetite and are linked with the level and extent of tobacco use. To relieve withdrawal symptoms medications can be prescribed. In…

Clinical Definition Nocturia is a fairly common condition in which a patient has to wake up at night to void the bladder (i.e., urinate). In Our Own Words Most people can sleep six to eight hours without needing to urinate, but patients with nocturia awaken at least once — and frequently, many additional times —…

Clinical Definition Nocturnal polyuria is an excessive volume of urination at nighttime. Etiologies include, excessive fluid intake (especially of caffeine or alcohol), congestive heart failure, renal insufficiency, and other conditions. Diagnosis depends on a careful health history, physical exam, evaluation of a voiding diary, tests such as urinalysis and urodynamic tests; treatment includes treating underlying…

Clinical Definition Non-Hodgkin lymphoma is a group of hematologic malignancies that originate in the lymphocytes. The cancerous lymphocytes multiply and do not function normally, compromising immune system functions. There are many subtypes of non-Hodgkin’s lymphoma classified according to whether they arise from T cells or B cells and whether they are indolent or aggressive. In Our Own Words…

Clinical Definition Non-steroidal anti-inflammatory medications, or NSAIDs, are commonly recommended to relieve pain and decrease inflammation (the body’s response to injury or irritation, marked by warmth, pain, swelling). They work by blocking production of inflammatory triggers. Besides helping to reduce fever, subdue a headache or ease minor aches caused by a cold, NSAIDs are often…