Step 1 Basics (USMLE)

4.02 Medium Vessel Vasculitis Rheumatology review for the USMLE Step 1 exam. Vasculitis: inflammation of blood vessels, classified by the size of the blood vessels affected Medium vessel vasculitis affects the main visceral arteries and veins, and their initial branches Three types of medium vessel vasculitis are discussed: polyarteritis nodosa, Kawasaki disease (mucocutaneous lymph node syndrome)...

4.01 Small Vessel Vasculitis Rheumatology review for the USMLE Step 1 exam Vasculitis is inflammation of blood vessels and is classified into three categories based on vessel size: large, medium, and small vessel vasculitis. Small vessel vasculitis affects arterioles, capillaries, and venules, leading to symptoms associated with damage to these vessels, such as palpable purpura. Five types of smal...

HIGH YIELD 1: Top Weird Drug Reactions Review for the USMLE Step 1 exam The podcast discusses high yield weird drug side effects that are unexpected. Cyanopsia (blue vision) with sildenafil (PDE-5 inhibitor) Hepatic necrosis with halothane (inhaled anesthetic) Tendon/cartilage damage with fluoroquinolones (antibiotics) Cinchonism with quinidine (class IA antiarrhythmic) Hemorrhagic cystitis with c...

3.30 Spirochetes Microbiology review for the USMLE Step 1 Exam Spirochetes are spiral or corkscrew-shaped bacteria that stain gram negative. They have a unique endoflagella that distinguishes them from other species of bacteria. The endoflagella rotates within the periplasmic space and causes the bacteria to move, acting as its own propeller. Borrelia burgdorferi, Treponema pallidum, and Leptospir...

3.29 Mycoplasma and Ureaplasma Microbiology review for the USMLE Step 1 Exam Mycoplasma and Ureaplasma are bacteria without cell walls, making them invisible to gram stain. They cause respiratory and genital infections and have a cell membrane containing cholesterol. Main species causing infections in humans include Mycoplasma pneumoniae, Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma u...

3.28 Klebsiella Pneumoniae  Microbiology review for the USMLE Step 1 Exam Klebsiella pneumoniae is a lactose-fermenting, gram-negative bacilli that causes pneumonia and is part of the normal GI flora in humans. It causes infection when introduced to the respiratory tract and is commonly found in hospitals, making it a common cause of nosocomial pneumonia. Risk factors for klebsiella pneumonia incl...

3.27 Chlamydia Species Microbiology review for the USMLE Step 1 exam Chlamydia is a gram-negative bacteria that is an obligate intracellular organism. It has a two-part life cycle involving the reticular body (active form) and elementary body (inactive form). There are three main species of chlamydia that cause human infections: chlamydia trachomatis, chlamydia pneumoniae, and chlamydia psittaci....

3.26 Pseudomonas Aeruginosa Microbiology review for the USMLE Step 1 Exam Pseudomonas aeruginosa is an encapsulated gram-negative oxidase positive rod that causes a variety of diseases. It can be found in soil, hospitals, and water, and it particularly likes water. P. aeruginosa can enter the body through contact with water, inhalation of respiratory droplets, or by medical equipment. The symptoms...

 3.25 Proteus Species Microbiology review for the USMLE Step 1 exam Proteus species are gram-negative rods that cause hospital acquired urinary tract infections They have swarming motility and can move quickly in a coordinated fashion across surfaces due to their numerous flagella They can self-elongate and secrete a sticky polysaccharide when in contact with solid surfaces, allowing for attachmen...

3.24 Salmonella Species Microbiology review for the USMLE Step 1 Exam Salmonella are gram-negative bacteria that cause gastrointestinal disease. They have flagella that enable them to move around and infect cells, and can live inside macrophages. There are two categories of salmonella species: typhoidal and non-typhoidal. Typhoidal salmonella, such as salmonella typhi, cause typhoid fever and are...

3.23 Yersinia Species Microbiology review for the USMLE Step 1 Exam Yersinia are gram-negative, non-motile bacteria that cause zoonotic diseases. Yersinia produce urease enzyme to survive in the stomach and are facultative intracellular bugs. Three species of yersinia causing disease in humans are Yersinia pestis, Yersinia enterocolitica, and Yersinia pseudotuberculosis. The Yersinia species inhib...

3.22 Escherichia Coli (E. Coli) Microbiology review for the USMLE Step 1 Exam Esherichia coli (E. coli) is a lactose-fermenting, gram-negative rod causing various diseases, ranging from mild gastroenteritis to septic shock. E. coli diseases can be divided into two categories: intestinal infections and extraintestinal infections (outside the GI system). E. coli is part of the normal flora in the hu...

2.22 Tuberculosis Pulmonary system review for the USMLE Step 1 Exam Tuberculosis is caused by Mycobacterium tuberculosis bacteria and mainly affects the lungs. It is more common in developing countries, with India, Indonesia, China, Nigeria, Pakistan, and South Africa having the most TB deaths worldwide. TB is spread through inhaling infected aerosolized droplets, making crowded places hotspots fo...

2.21 Pneumonia: Lobar, Broncho, and Interstitial Pulmonary system review for the USMLE Step 1 Exam Pneumonia is an infection of the lung parenchyma that deals with gas exchange Three classic patterns of pneumonia: lobar, bronchopneumonia, and interstitial pneumonia Lobar pneumonia involves a single lobe of the lung and has four stages: congestion, red hepatization, gray hepatization, and resolutio...

2.20 Pneumothorax Pulmonary system review for the USMLE Step 1 Exam Pneumothorax is a collection of air outside the lung in the pleural cavity, caused by a hole in the pleurae that allows air to infiltrate and disturb normal respiratory function. There are three categories of causes: primary spontaneous, secondary spontaneous, and trauma. Trauma, such as blunt force or penetrating wounds, is the m...

2.19 Pleural Effusions: Transudate vs Exudate Pulmonary system review for the USMLE Step 1 Exam Pleural effusion is an abnormal accumulation of fluid in the pleural cavity. Pleural effusions can be characterized as either exudative or transudative based on the content of the extra fluid. Exudative effusions have high protein and lactate dehydrogenase content, while transudative effusions have low...

2.18 Digital Clubbing Pulmonary system review for the USMLE Step 1 Exam Digital clubbing is the enlargement of the ends of fingers and toes due to growth of connective tissue between the nail matrix and the distal portion of the digit. It is defined quantitatively as an increased angle between nail bed and nail plate (> 180°). Digital clubbing is caused by an interaction between platelets, megakar...

2.17 Pickwickian Syndrome Pulmonary system review for the USMLE Step 1 Exam Pickwickian Syndrome is also called obesity hypoventilation syndrome Characterized by daytime hypoventilation leading to hypercapnia Often occurs in individuals with a BMI over 30 Excess fat puts pressure on lungs and reduces ability to fully inflate Reduction in ventilatory drive may also cause hypercapnia Typical patient...

2.16 Sleep Apnea Pulmonary system review for the USMLE Step 1 Exam Sleep apnea is the repeated severe decrease or cessation of airflow into the lungs for more than 10 seconds during sleep, which causes the person to stop breathing for more than 10 seconds while they're sleeping. There are two types of sleep apnea: obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea occurs when...

2.15 Pulmonary Hypertension Pulmonary system review for the USMLE Step 1 Exam Pulmonary hypertension is elevated blood pressure within the pulmonary arteries at rest, defined as a mean pulmonary artery pressure above 20 mmHg. Primary pulmonary hypertension is high blood pressure in the pulmonary arteries that is not caused by some underlying disease, while secondary pulmonary hypertension is high...

2.14 Acute Respiratory Distress Syndrome (ARDS) Pulmonary system review for the USMLE Step 1 Exam Acute respiratory distress syndrome (ARDS) is an acute, diffuse, inflammatory form of lung injury that is life-threatening for patients. ARDS is a response from the lungs to severe injury, most commonly caused by sepsis, but can also be caused by pneumonia, trauma, drowning, toxin inhalation, and panc...

2.13 Sarcoidosis Pulmonary system review for the USMLE Step 1 Exam Sarcoidosis is a multisystem inflammatory disorder with non-caseating granulomas in various organs Most commonly affects the lungs and causes restrictive lung disease Classic patient is a young black female in her 20-30s, but can affect any gender or race Symptoms vary depending on which organs are affected, and can include uveitis...

3.21 H. Pylori Microbiology review for the USMLE Step 1 exam Helicobacter Pylori (H. Pylori) is a gram-negative, comma-shaped bacteria that causes chronic gastritis Estimated that 50% of people worldwide are infected with H. Pylori; higher in developing countries, lower in developed countries More common in populations with lower socioeconomic status and in crowded conditions with poor hygiene Spr...

3.20 Vibrio Species Microbiology review for the USMLE Step 1 Exam Vibrio species are gram negative comma-shaped rods with a single flagellum, allowing them to move quickly Two main species that cause human infections: Vibrio cholerae and Vibrio vulnificus Vibrio cholerae causes foodborne disease called cholera through cholera toxin secretion, spread through the fecal-oral route in developing count...

3.19 Campylobacter Jejuni Microbiology review for the USMLE Step 1 exam Campylobacter jejuni is a gram-negative, comma-shaped bacteria that causes diarrheal illness It is the most common cause of bacterial diarrhea in the US It can be distinguished from other gram-negative, comma-shaped bacteria by its desired culture temperature of 42C/107F It is mostly acquired through consumption of raw milk, u...