Substance use disorder (SUD) refers to a pattern of substance use—be it nicotine, cannabis, cocaine, or something else—that causes significant impairment or distress to the user. SUD is prevalent and growing in the United States and around the world. People of any age may be at risk for developing a substance use disorder. But exposure to and experimentation with alcohol and drugs usually begins in early adolescence. Many adolescents experiment with substances and then taper down or stop using them. Others continue to advance their drug use, leading to a diagnosable substance use disorder with ..read more

Megaloblast. Now there’s a word you don’t hear every day. The root -blast (from the Greek blastos, meaning germ or bud) may be somewhat familiar since we talk about blast cells (very young hematopoietic precursor cells) in hematology. And megalo- (from the Greek megas, meaning large or great) is also used fairly frequently, as in splenomegaly (enlargement of the spleen). So does “megaloblast” just mean a large, immature cell? We’ll answer this question, and many more, in this discussion of megaloblastic anemia. After listening to this AudioBrick, you should be able to: Describe the ..read more

Blood glucose is proof that you can have too much of a good thing. While glucose serves a critical role as fuel for many of our bodily functions, it must remain in a very tightly controlled range. If the level goes too low, you can fall into a coma. If glucose is too high, damage to tissues throughout the body can occur. When blood glucose is consistently too high and the mechanisms that return it to the normal range fail, this is called diabetes mellitus. Nearly 10% of the US population has a form of diabetes, so it is critical that physicians understand the disease and be prepared to care fo ..read more

Gallstones are the hardened precipitates—“stones”—of the substrates found in bile. The liver makes bile to help digest fats, and the bile is stored in the gallbladder. When there is an excess of a particular substance in the bile (eg, cholesterol or unconjugated bilirubin), gallstones form in the gallbladder. Gallstones can be as small as a grain of sand, as large as a golf ball, or any size in between. Gallstones are very common and usually do not cause any symptoms. But not all gallstones stay in the gallbladder. After listening to this AudioBrick, you should be able to: Define, compare, an ..read more

Normal blood pressure keeps us alive. It’s the force that moves blood throughout our circulatory system, ensuring that oxygen and nutrients reach our organs and tissues and that waste products are eliminated. When we hear the word hypertension—high blood pressure—we know this describes the blood flow exerting too much force against blood vessel walls. Pulmonary hypertension describes high blood pressure in the vessels of the lung. Specifically, pulmonary hypertension is an elevated mean arterial pressure (≥20 mm Hg at rest) of the vessels between the heart and the lung. After listening to this ..read more

Macroscopic Skin Lesions A thorough skin examination should be performed annually to assess for new or changing macroscopic skin lesions. It is critically important to be able to identify and describe normal and abnormal skin and to note your findings carefully, because a change in an existing skin lesion is the most common sign of skin cancer, including deadly ones like melanoma. In this discussion, we will describe the specific ways in which you document skin lesions, using a vocabulary that other clinicians will understand. After listening to this AudioBrick, you should be able to: Explain ..read more

Have you ever cut your finger, bumped your head, or fallen and scraped your knee? While you were cursing your clumsiness or bad luck, your body got straight to work healing the injury, relying on the wondrous process of acute inflammation. Shortly after your injury, you most likely experienced some or all of the cardinal signs of acute inflammation: pain (dolor), redness (rubor), heat (calor), and swelling (tumor). There are two types of inflammation: acute and chronic. Acute inflammation is an essential part of the body’s defense system and generally lasts a few days. Chro ..read more

Multiple endocrine neoplasias are familial syndromes of endocrine tumors occurring in endocrine organs throughout the body. Despite its acronym, the risk for acquiring MEN is about the same in men and women and also across geographic and racial and ethnic groups. These are rare syndromes, affecting about 1 in 30,000 people. Genetic mutations cause the MEN syndromes, which are then inherited in an autosomal dominant pattern. This means several members of the same family are often affected; an affected parent has a 50% chance of passing down the disease to his or her children. Unlike cancers wit ..read more

Myocarditis is the inflammation of the heart muscle. This muscle is the middle layer of the heart, formally called the myocardium, hence the name myocarditis (the -itis suffix indicates inflammation). Inflammation of the myocardium can be caused by a variety of etiologies, from infection to drugs. If severe enough, inflammation can lead to necrosis and cardiomyocyte death. This is dangerous because the heart is considered permanent tissue. This means there is limited regenerative potential, so tissue loss is essentially permanent. As part of the healing process, myocardial tissue is replaced b ..read more

Learning is traditionally defined as acquiring knowledge through study, experience, or being taught. In psychology, it is often defined as a relatively lasting change in behavior that results from experience. Learning is an ongoing process; we continue learning throughout our entire lives. After listening to this AudioBrick, you should be able to: Name and briefly describe the three major theories of learning. Define classical conditioning, including unconditioned stimulus, unconditioned response, neutral stimulus, conditioned stimulus, and conditioned response. Define operant conditioning an ..read more