Step 1 Basics (USMLE)

4.11 Antibody Review Rheumatology review for the USMLE Step 1 Exam. ANA Principles ANA (Anti-Nuclear Antibody): Non-specific antibody. Reacts against nuclear antigens, including proteins, DNA, RNA, and nucleic acid-protein complexes. Includes a group of antibodies such as anti-dsDNA, anti-histone, SSA/Ro, SSB/La, Scl-70, anti-aminoacyl-tRNA synthetase (Jo-1). Found in 20-30% of the general public without connective tissue disorder symptoms. ANA+ individuals may or may not have a rheumatologic disorder. Further workup is needed in ANA+ cases to determine the specific disorder. Antibodies by Disease Process Systemic Lupus Erythematosus (SLE) Anti-dsDNA antibody. Anti-Smith antibody. Drug-Induced Lupus Anti-histone antibody. Diffuse vs. Limited Scleroderma Diffuse: Anti-Scl-70 (anti-topoisomerase I). Limited: Anti-centromere (often called CREST syndrome, with CREST standing for centromere). Sjogren's Syndrome Anti-SSA (Ro). Anti-SSB (La), which usually occurs in the presence of SSA. SSA is considered the Sjogren-specific antibody, leading to the presence of SSB. Rheumatoid Arthritis (RA) Anti-CCP (Cyclic Citrullinated Peptide). RF (Rheumatoid Factor) is non-specific. Thanks for listening!

4.10 Gout and Pseudogout Rheumotology review for the USMLE Step 1 Exam. Gout Caused by uric acid crystal deposition due to purine metabolism. Triggers inflammation when crystals precipitate in cooler joint fluid. Presents with severe, red, and swollen monoarticular joints, often in the big toe. Diagnosis through synovial fluid analysis. Acute treatment: colchicine, NSAIDs, and glucocorticoids. Preventive treatment: allopurinol, febuxostat, probenecid, and lifestyle changes. Pseudogout Resulting from calcium pyrophosphate crystal deposition, often due to ATP breakdown. Manifests with painful, swollen joints, typically affecting multiple upper extremity joints, especially the knee. Diagnosis through synovial fluid analysis. Acute treatment resembles gout management. No direct preventive treatment to lower calcium pyrophosphate levels. Thanks for listening!

4.09 Rheumatologic Emergencies Rheumatology review for USMLE Step 1 Exam Giant Cell Arteritis (GCA) A large vessel vasculitis, mainly in older individuals. Symptoms: headache, jaw claudication, vision loss. Ischemia from granulomas in large vessels causes vision loss. Immediate high-dose corticosteroids are crucial. Scleroderma Renal Crisis A complication of scleroderma. Symptoms: finger edema, skin tightening, sudden hypertension, rising creatinine. Renal artery fibrosis leads to high blood pressure. Treat with IV ACE inhibitor, not steroids. Acute Transverse Myelitis in SLE Inflammation of the spinal cord in lupus. Symptoms: bilateral numbness, tingling, weakness. Treat with corticosteroids. Catastrophic Antiphospholipid Syndrome (CAPS) A rare, life-threatening form of APS. Symptoms: unexplained miscarriages, unexplained clots, multiorgan failure. Treat with anticoagulation followed by immune suppression

1.06 Systolic Heart Murmurs Cardiovascular system review for the USMLE STEP 1 Exam Heart murmurs are caused by turbulent blood flow in the heart There are 4 different types of systolic murmurs: ventricular septal defect (VSD), patent ductus arteriosus (PDA), aortic stenosis, and mitral or tricuspid regurgitation PDA produces a constant, machine-like murmur VSD produces a harsh holosystolic murmur Aortic stenosis produces a crescendo-decrescendo systolic ejection murmur Mitral and tricuspid regurgitation produce a holosystolic high pitched "blowing" murmur Mitral valve prolapse produces a mid-systolic click followed by a late systolic murmur Aortic regurgitation produces a decrescendo diastolic murmur Mitral stenosis produces a rumbling diastolic murmur  

5.13 OCD and Related Disorders Psych review for the USMLE Step 1 Exam Obsessive Compulsive Disorder (OCD): Unwanted thoughts (obsessions) and repetitive behaviors (compulsions). Treat with CBT + SSRIs/SNRIs. Tic Disorders: Tourette Syndrome involves multiple motor and at least one vocal tic. Treat with Habit Reversal Therapy. Body Dysmorphic Disorder: Preoccupation with minor flaws, treat with SSRIs and CBT. Trichotillomania: Hair pulling disorder, treat with Habit Reversal Training and sometimes SSRIs. PANDAS: Pediatric disorder after strep infection, sudden OCD-like symptoms. Treat with antibiotics, CBT, and SSRIs.

5.12 Anxiety Related Disorders Psychiatry review for the USMLE Step 1 Exam Anxiety is a normal response to threats or stressors in the environment Anxiety disorders occur when anxiety causes significant distress or impairment in functioning Generalized Anxiety Disorder (GAD) involves persistent and excessive worry about various aspects of daily life for at least 6 months, accompanied by physical symptoms Treatment for GAD typically involves a combination of cognitive-behavioral therapy (CBT) and selective serotonin reuptake inhibitors (SSRIs) Panic Disorder is diagnosed in individuals who experience spontaneous panic attacks and fear future attacks Panic attacks are acute episodes of intense anxiety and physical symptoms Treatment for Panic Disorder involves CBT and SSRIs, with SSRIs being the first-line medication Agoraphobia is the fear of being in public places where escape may be difficult and often follows a traumatic event CBT and SSRIs are the recommended treatment for Agoraphobia Social Anxiety Disorder (Social Phobia) involves fear of scrutiny or embarrassment in social situations Public speaking can be a significant trigger for individuals with social anxiety disorder Beta blockers can be used to treat social anxiety disorder by reducing physical symptoms Treatment for social anxiety disorder usually involves CBT, SSRIs, or beta blockers.

5.11 Eating and Feeding Disorders Psychiatry Review for the USMLE Step 1 Exam Eating Disorders: Main disorders: bulimia nervosa, anorexia nervosa, and binge eating disorder. Bulimia and anorexia share anxiety and compensatory behaviors. Anorexia: low body weight, fear of gaining weight, treatment involves slow refeeding. Bulimia: normal weight, signs of forced vomiting, treated with CBT and SSRIs. Binge Eating Disorder: uncontrollable eating, negative emotions, SSRIs and CBT for treatment. Feeding Disorders: Occur in children, not related to body image. Common disorders: avoidant/restrictive food intake disorder, rumination disorder, and pica. Avoidant/Restrictive Food Intake Disorder: avoidance or restriction of food intake. Pica: eating non-nutritious substances, common in young children. Rumination Disorder: regurgitation without associated symptoms.

5.10 Mood Disorders (Depression and Bipolar) Psychiatry Review for the USMLE Step 1 exam Mood disorders are persistent disruptions in emotion, categorized into bipolar disorders and depressive disorders. Bipolar disorders are characterized by manic or hypomanic episodes, while depressive disorders feature periods of depression. Major Depressive Disorder (MDD) is characterized by feelings of sadness, guilt, worthlessness, and anhedonia lasting for at least two weeks. SIG E CAPS is an acronym used to remember the symptoms of depression: Sleep changes, Interest loss, Guilt, Energy loss, Concentration difficulties, Appetite changes, Psychomotor retardation, and Suicidal ideation. In MDD, at least 5 of the SIG E CAPS symptoms must persist for more than 2 weeks. Persistent Depressive Disorder (dysthymia) is a chronic, low-grade form of MDD that lasts for at least two years. Mania is a symptom common to all bipolar disorders, characterized by elevated or irritable mood and increased activity or energy. Mania lasting for at least 1 week is called a manic episode, while hypomania is a less severe form lasting longer than 4 days. The symptoms of mania can be remembered using the mnemonic DIG FAST: Distractibility, Irritable mood/insomnia, Grandiosity, Flight of ideas, Agitation/increased activity, Speedy thoughts/speech, and Thoughtlessness. Bipolar I involves manic episodes, and bipolar II involves hypomanic episodes and major depressive episodes. Bipolar I requires at least one manic episode, while bipolar II requires depressive episodes. Mood stabilizers such as lithium, valproate, carbamazepine, and lamotrigine are used to treat bipolar disorders. Litium is the best (notable exeptions however). Antidepressants are contraindicated for bipolar patients due to the risk of flipping into mania. The risk of suicide is high in bipolar patients, with 25-50% attempting suicide and 10-15% dying by suicide. Cyclothymia is a less common form of bipolar disorder characterized by cycling between hypomania and mild depression over many years.

5.09 Schizophrenia Psychiatry review for the USMLE Step 1 Exam Epidemiology: Slight male predilection (1.4:1 male to female ratio). Men present between 18-25, women between 28-35. Affects about 0.5% of the population. Symptoms: Positive symptoms: hallucinations, delusions, disorganized behavior and speech. Negative symptoms: flat affect, anhedonia, apathy, alogia, lack of interest in socialization. Cognitive symptoms: impairments in attention, executive function, working memory. Diagnosis: Criteria: two or more symptoms lasting over a month. Schizophreniform disorder if symptoms last less than 1 month. Pathophysiology: Excess dopamine in prefrontal cortical pathway (negative symptoms). Excess dopamine in mesolimbic pathway (positive symptoms). Other neurotransmitters may also play a role (especially serotonin excess). Treatments: Antipsychotics (D2 receptor antagonists). First-generation antipsychotics: haloperidol, chlorpromazine (more side effects). Second-generation antipsychotics (atypical antipsychotics): aripiprazole, olanzapine, quetiapine, risperidone (lower extrapyramidal side effects, higher metabolic side effects). Outcomes: Rule of thirds: one-third full recovery, one-third improved with mild symptoms, one-third require high-level care.  

5.08 Cluster C Personality Disorders Psychiatry review for the USMLE Step 1 Exam Introduction: Cluster C personality disorders = anxious/worried. Disorders: avoidant, obsessive-compulsive, dependent. Distinguish from normal traits. Avoidant Personality Disorder: Inhibited, introverted, anxious. Fear of rejection, low self-esteem. Characteristics: avoidance, preoccupation with criticism/rejection, social ineptness. Treatment: Anti-anxiety drugs may help temporarily. Obsessive-Compulsive Personality Disorder: Perfectionism, inflexibility, diligence. Not OCD; need for control, not obsessions/compulsions. Characteristics: details, work focus, rigidity. Example: Mark, unemployed with attention to detail. Dependent Personality Disorder: Excessive reliance on others for support/decisions. Linked to early medical/psychiatric conditions. Characteristics: decision-making, fear of disapproval, reliance. Example: Bob, farm laborer dependent on mother. Conclusion: Cluster C = anxiety-driven. Understand characteristics, not specific diagnoses. Examples show impact on lives.

5.07 Cluster B Personality Disorders Psychiatry review for USMLE Step 1 Exam Cluster B personality disorders are the highest yield among all personality disorders. The cluster B disorders include borderline personality disorder, histrionic personality disorder, narcissistic personality disorder, and antisocial personality disorder. Substance abuse and comorbid mood disorders, particularly major depressive disorder (MDD), are commonly associated with cluster B disorders. Personality disorders are distinguished from normal personality traits by their negative impact on daily life, lack of awareness of the problem, and deviation from cultural expectations. Borderline personality disorder is characterized by unstable emotions, impulsivity, disturbed relationships, and potential psychotic features. Criteria for diagnosing borderline personality disorder include frantic efforts to avoid abandonment, unstable interpersonal relationships, identity disturbance, impulsivity, recurrent suicidal behavior, affective instability, chronic feelings of emptiness, inappropriate anger, and paranoid ideation or dissociative symptoms under stress. Borderline personality disorder has a high risk of suicide, especially in women, and is often treated with dialectical behavior therapy (DBT). Histrionic personality disorder involves excessive attention-seeking, inappropriate sexually seductive behavior, shallow emotional expression, and self-dramatization. Diagnostic criteria for histrionic personality disorder include discomfort when not the center of attention, sexually provocative behavior, emotional instability, attention to physical appearance, impressionistic speech, self-dramatization, and susceptibility to influence. Histrionic personality disorder is more common in women and is associated with the defense mechanism of regression. Narcissistic personality disorder is characterized by grandiosity, a need for admiration, lack of empathy, and a sense of entitlement. Diagnostic criteria for narcissistic personality disorder include a grandiose self-importance, fantasies of unlimited success, a belief in being unique, excessive need for admiration, sense of entitlement, exploitation of others, lack of empathy, envy, and arrogant behavior. Narcissistic personality disorder is exemplified by individuals who exhibit characteristics similar to a former president (not mentioned by name), including being grandiose, preoccupied with success, and envious of others. Antisocial personality disorder, often referred to as sociopathy, involves a disregard for others' rights, lack of remorse, criminal behavior, hostility, and manipulation. Antisocial personality disorder is more common in males, has a high prevalence in incarcerated individuals, and is usually preceded by childhood conduct disorder. Diagnostic criteria for antisocial personality disorder include failure to conform to social norms, deceitfulness, impulsivity, aggressiveness, disregard for safety, irresponsibility, and lack of remorse.

5.06 Cluster A Personality Disorders Psychiatry review for the USMLE Step 1 Exam. The cluster A personality disorders include paranoid, schizoid, and schizotypal. These disorders are characterized by individuals who are perceived as weird, awkward, and quiet. Personality disorders differ from normal personality quirks based on their negative impact on daily life, lack of awareness of the problem, and deviation from cultural expectations. Paranoid Personality Disorder: Patients are chronically suspicious and distrustful of others, without persistent fixed delusions. Key characteristics include unwarranted suspicions, doubts about loyalty, reluctance to confide, reading hidden meanings, holding grudges, perceiving attacks on reputation, and suspicion of infidelity. Schizoid Personality Disorder: Individuals prefer isolation and have difficulty forming relationships. Criteria for diagnosis include a lack of interest in close relationships, solitary activities, indifference to praise or criticism, emotional coldness, and flattened affectivity. Schizotypal Personality Disorder: Considered a less severe form of schizophrenia, with odd behavior, speech, thinking, and mild perceptual experiences. Notable features include social isolation, "magical" beliefs, mild paranoia, constricted affect, and social anxiety.

5.05 Hallucinogens (Types, Intoxication, and Withdrawal) Psychiatry review for the USME STEP 1 Exam. Hallucinogens are a diverse class of drugs that cause hallucinations and other symptoms. Common hallucinogens discussed in the podcast are LSD, marijuana, PCP, and ketamine. LSD activates serotonin receptors, causing visual and auditory hallucinations, time and reality distortions, mood elevation, and dilation of the pupils. No notable withdrawal symptoms. Marijuana acts as a depressant, stimulant, and hallucinogen. THC binds to cannabinoid receptors, increasing neurotransmitters like dopamine and serotonin. Intoxication symptoms include red eyes, anxiety, euphoria, increased appetite, dry mouth, paranoid delusions, and perceived slowed time. Mild withdrawal symptoms include irritability, depression, sleep problems, and decreased appetite. Heavy cannabis use in adolescence is linked to an increased risk of schizophrenia. PCP antagonizes NMDA glutamate receptors and activates dopaminergic neurons. Intoxication symptoms include increased pain threshold, agitation, hallucinations, nystagmus, ataxia, and tachycardia. No notable withdrawal symptoms. Ketamine is structurally similar to PCP and acts as a milder version. It causes hallucinations and dissociation and is used medically for analgesia.  

5.04 Depressants (Types, Intoxication, and Withdrawal) Psychiatry review for the USMLE Step 1 exam. Depressants decrease neuronal activity in the brain. They can work by stimulating GABAergic neurons or binding to opiate receptors. Common GABA-promoting depressants: alcohol, benzodiazepines, barbiturates, and inhalants. Opioid depressants include heroin and morphine derivatives. Alcohol enhances GABA receptor effects, inhibits glutamate activity, and causes intoxication symptoms such as disinhibition, slurred speech, impaired motor control, lethargy, respiratory depression, and coma. Alcohol withdrawal symptoms include anxiety, agitation, insomnia, nausea/vomiting, tremors, autonomic dysfunction, seizures, and can be life-threatening (delirium tremens). Benzodiazepines bind to the benzodiazepine receptor, enhance GABA effects, and cause intoxication symptoms similar to alcohol. Benzodiazepine withdrawal symptoms include anxiety, agitation, insomnia, and seizures, which are treated with a gradual tapering of the drug. Inhalants depress brain activity and cause symptoms such as disinhibition, paranoia, lethargy, dizziness, ataxia, slurred speech, and high doses can lead to respiratory depression and brain damage. Opioids bind to opioid receptors, reduce pain, improve mood, and cause intoxication symptoms like drowsiness, constricted pupils, seizures, and respiratory depression. Opioid overdose can be reversed with naloxone, an opioid receptor antagonist. Opioid withdrawal symptoms include dysphoria, anxiety, weakness, sweating, dilated pupils, and diarrhea, and can be managed with medications like methadone and buprenorphine. Alcohol withdrawal is an emergency and requires prompt treatment with benzodiazepines.

5.03 Stimulants (Types, Intoxication, and Withdrawal) Psychiatry review for the USMLE Step 1 Exam. Stimulants increase CNS activity and activate the sympathetic nervous system. They can block reuptake of neurotransmitters or stimulate their release. Intoxication symptoms include agitation, dilated pupils, sweating, euphoria, hallucinations, and increased norepinephrine, epinephrine, dopamine, and serotonin levels. Prescribed stimulants: amphetamine, dextroamphetamine, and methylphenidate (used for ADHD). Recreational stimulants: methamphetamine, cocaine, MDMA, nicotine, and caffeine. Cocaine blocks reuptake of norepinephrine, epinephrine, and dopamine, and can cause hallucinations, paranoia, chest pain, and potentially cardiac death. Methamphetamine can cause tactile hallucinations where patients feel like bugs are crawling on their skin. MDMA can induce feelings of connectedness, heightened emotions, and hallucinations. Withdrawal from stimulants, particularly cocaine and methamphetamine, is characterized by depression, headache, malaise, fatigue, hypersomnolence, anhedonia, constricted pupils, vivid dreams, and flu-like symptoms. Withdrawal symptoms are opposite to the effects experienced during intoxication.

5.02 Classical and Operant Conditioning Psychiatry review for the USMLE Step 1 Exam Classical Conditioning: Pavlovian conditioning discovered by Ivan Pavlov, a Russian physiologist known for his experiments with dogs. Learning through association. Example: Conditioning dogs to respond to a noise the way they would respond to meat. Involves associating an unconditioned stimulus with a new conditioned stimulus to elicit the same response. Process of Classical Conditioning: Start with a stimulus that produces a response (e.g., smelling pizza makes you hungry). Pair the stimulus and response with an unconditioned stimulus (e.g., receiving a text indicating pizza delivery). Eventually, the conditioned stimulus (the text notification) alone elicits the conditioned response (mouth watering). Extinction and Spontaneous Recovery in Classical Conditioning: If the conditioned stimulus (text notification) is presented without the unconditioned stimulus (pizza), the conditioned response (mouth watering) will weaken and eventually extinguish. Spontaneous recovery may occur, where the conditioned behavior briefly reappears after a period of extinction. Terms in Classical Conditioning: Unconditioned stimulus (US): Triggers a response unconditionally. Unconditioned response (UR): The response elicited by the unconditioned stimulus. Conditioned stimulus (CS): Initially neutral stimulus that becomes associated with the unconditioned stimulus. Conditioned response (CR): The response elicited by the conditioned stimulus. Operant Conditioning: Developed by B.F. Skinner. Learning occurs through rewards and punishments for behavior. Three types of responses: neutral operants, reinforcers, and punishers. Examples of Operant Conditioning: Positive reinforcement: Giving a child candy for good behavior. Negative reinforcement: Taking away a child's phone until homework is done to increase desired behavior. Positive punishment: Using physical force as punishment (not recommended). Negative punishment: Taking away a child's phone to decrease unwanted behavior. Different Schedules of Reinforcement: Continuous Reinforcement: Positive reinforcement every time a specific behavior occurs. Fixed Ratio Reinforcement: Reinforcement after a specified number of correct responses. Fixed Interval Reinforcement: Reinforcement after a fixed time interval with at least one correct response. Variable Ratio Reinforcement: Reinforcement after an unpredictable number of responses. Variable Interval Reinforcement: Reinforcement after an unpredictable amount of time. Summary: Classical conditioning involves learning through association of stimuli. Operant conditioning involves learning through rewards and punishments for behavior.

5.01 Ego Defenses Psychiatry review for the USMLE Step 1 Exam Defense mechanisms protect the unconscious part of our personality from anxiety caused by unacceptable thoughts or feelings. Ego defenses are categorized into three groups: mature, neurotic, and immature. Immature defense mechanisms include projection, regression, denial, acting out, and splitting. Projection involves attributing objectionable thoughts or emotions to others. Regression is behaving in an age-inappropriate way to avoid tension associated with the current phase of development. Denial is not accepting or believing something to protect one's ego. Acting out involves giving in to socially inappropriate impulses to avoid anxiety. Splitting is viewing people as either all good or all bad, without considering the middle ground. Neurotic defense mechanisms include intellectualization, isolation of affect, displacement, rationalization, reaction formation, and repression. Intellectualization is overanalyzing situations or focusing on irrelevant details to avoid negative feelings. Isolation of affect is unconsciously limiting the experience of emotions associated with a stressful event. Displacement involves shifting emotions from one thing to another, which is deemed more acceptable. Rationalization is justifying one's behavior or negative feelings through rational explanations. Reaction formation is unconsciously acting opposite to an unacceptable impulse. Repression involves preventing thoughts or feelings from entering consciousness to avoid negative emotions. Mature defense mechanisms include humor, altruism, suppression, and sublimation. Humor is used to relieve anxiety and negative thoughts. Altruism involves performing beneficial acts for others to experience pleasure and relieve anxiety. Suppression is consciously blocking undesirable ideas, thoughts, or impulses. Sublimation is transforming anxiety or emotions into socially valued pursuits. Sublimation involves channeling negative emotions into productive and socially desirable actions.

4.08 Myasthenia Gravis and Lambert Eaton Syndrome MSK/Rheumatology review for the USMLE Step 1 Exam Introduction: Review of neuromuscular junction and its components: presynaptic part, postsynaptic part, synaptic cleft. Cascade of events leading to the release of acetylcholine into the synaptic cleft. Myasthenia Gravis: Autoimmune neuromuscular junction disease. Fluctuating muscle weakness, especially ocular and eyelid weakness, distal limb weakness. Antibodies target nicotinic acetylcholine receptors (n-AChR's). Association with thymic hyperplasia and enlarged thymus. Treatment: Acetylcholinesterase inhibitors (AChE inhibitors), immunosuppressants. Lambert Eaton Syndrome: Autoimmune neuromuscular junction disease associated with cancer. Fluctuating muscle weakness, autonomic dysfunction, decreased reflexes. Antibodies target presynaptic calcium channels on nerve terminals. Autonomic manifestations due to calcium channels also present in smooth muscle. Around 50% of cases associated with an underlying malignancy. Treatment: Immunosuppression, addressing underlying malignancy if present.

This high yeild podcast covers schizophrenia type disorders for the USMLE Step 1 exam. I cover the following topics: Defining psychotic symptoms: hallucinations, delusions, and disorganized thoughts/speech Example of a delusional belief about a small being inside the body Schizophrenia spectrum disorders: schizophrenia, schizophreniform, and brief psychotic disorder Differentiating the disorders based on the duration of symptoms: brief (6 months) Progression from brief psychotic disorder to schizophreniform to schizophrenia Schizoaffective disorder: combination of schizophrenia and a mood disorder (MDD) Highlighting the importance of episodes with only schizophrenia symptoms in schizoaffective disorder Delusional disorder: focusing on delusions without hallucinations, disorganized thoughts/behavior, or mood disorders Contrasting delusions in delusional disorder with those in schizophrenia Litigious tendencies observed in delusional disorder cases Mood disorders with psychotic features: exploring MDD as an example Psychotic symptoms in MDD appear only during depressive episodes Clarifying the distinction between psychotic symptoms in MDD and schizoaffective disorder Summary: Understanding the different disorders and their symptom overlap.

4.07 Polymyositis and Dermatomyositis MSK/Rheum review for the USMLE Step 1 Exam Polymyositis and dermatomyositis are autoimmune inflammatory myopathies. They are caused by abnormal activation of T cells that attack skeletal muscle and both cause proximal muscle weakness, especially of the shoulders and pelvic girdle muscles. Polymyositis develops when there is abnormal activation of CD8 T cells, while dermatomyositis is primarily attacked by CD4 T cells. Both are diagnosed through a muscle biopsy and the presence of elevated CK levels and several different autoantibodies. Dermatomyositis includes dermatologic manifestations, such as gottron papules, heliotrope rash, and shawl rash. Both are associated with MI, interstitial lung disease, and various types of cancer (dermatomyositis more so). Both diseases require prompt treatment with steroids and immunosuppressive agents.

4.06 Osteoarthritis vs Rheumatoid Arthritis Rheumatology review for the USMLE Step 1 exam Rheumatoid arthritis and osteoarthritis both cause joint inflammation, joint pain, and can limit joint range of motion Osteoarthritis is a degenerative joint disease that occurs when the articular cartilage that covers the ends of bones begins to degrade and erode The most common joints affected by osteoarthritis are the hips and knees, and the distal interphalangeals of the hands are also commonly affected Osteoarthritis tends to be more asymmetric and localized, presenting as a single degenerated joint Rheumatoid arthritis is an inflammatory autoimmune disease that affects the joints and other parts of the body RA typically develops in patients who are genetically predisposed and triggered by environmental factors, such as smoking The two autoantibodies present in RA are rheumatoid factors and anti-cyclic citrullinated peptide (anti-CCP) antibodies Rheumatoid factors activate the complement system and stimulate the inflammatory response in the body. Anti-CCP antibodies bind citrullinated peptides and stimulate inflammation in the synovium of joints Rhematoid arthritis has extra-articular manifestations, the most common of which are rheumatoid nodules

4.05 Scleroderma Rheumatology review for the USMLE Step 1 exam Scleroderma is a chronic autoimmune connective tissue disease that causes thickening and hardening of the skin, as well as fibrosis (excess deposition of collagen and other ECM proteins) throughout the body. Autoreactive immune cells activate endothelial cells, which produce large amounts of endothelin 1, leading to overactivation of fibroblasts that overexpress collagen. It typically affects younger women (35-50 years old) with a F:M ratio of 5:1. There are two distinct forms of scleroderma: diffuse (systemic) and limited, each associated with unique antibodies and clinical presentations. Diffuse scleroderma involves the skin and internal organs and is rapidly progressive. Skin tightens especially in the fingers, and internal organs including the lungs, kidneys, GI system, and heart can be affected. It is associated with anti-Scl-70 antibody and anti-RNA III polymerase. Limited scleroderma tends to only affect the skin, characterized by the mnemonic CREST: Calcinosis cutis, Raynaud phenomenon, Esophageal dysmotility, Sclerodactyly, and Telangiectasia. It is associated with anti-Centromere antibody. Treatment involves NSAIDs and DMARDs for musculoskeletal pain, H2 blockers or PPIs for esophageal reflux, and Ace inhibitors for scleroderma renal crisis. There is no cure for the disease.

HIGH YIELD 2: Marfan's vs Homocystinuria vs Ehlers-Danlos High yield review for the USMLE Step 1 exam. Marfan's syndrome, Ehlers-danlos, and homocystinuria are three distinct diseases that affect connective tissue. They share similarities like tall stature, long fingers, scoliosis, high arched palate, chest wall deformities, joint hypermobility, and lens dislocation. Marfan's syndrome is caused by FBN1 gene mutation on chromosome 15, and it results in defective fibrillin-1. It causes aortic root dilation, and upward lens dislocation. Homocystinuria is caused by a defect in homocysteine breakdown, and it results in elevated levels of homocysteine, which is toxic to the body. It causes thrombosis and downward lens dislocation. Ehlers-Danlos syndrome is caused by a deficiency in type III collagen, and it results in hyperextensible skin, easy bruising and bleeding. It can cause vascular rupture, and it usually occurs in the arterial system. Patients with Marfan's syndrome present with scoliosis, long fingers and toes, and caved-in chest wall. Patients with homocystinuria present with developmental delay, long fingers and toes, and upward lens dislocation. Patients with Ehlers-Danlos syndrome present with recurrent bruising, soft hyperextensible skin, and joint hyperextensibility

4.04 Systemic Lupus Erythematosus Rheumatology review for the USMLE Step 1 Exam Marfan's syndrome, Ehlers-danlos, and homocystinuria are three distinct diseases that affect connective tissue. They share some clinical features like tall stature, long fingers, scoliosis, high arched pallet, chest wall deformities, joint hypermobility, and lens dislocation. Marfans is caused by a mutation in the FBN1 gene, resulting in defective fibrillin-1, and the main complication is aortic root dilation. Homocystinuria is a metabolic disorder caused by a defect in homocysteine breakdown, leading to elevated levels of homocysteine, and the main complication is thrombosis. Ehlers-Danlos is caused by a deficiency in type III collagen, and the main complication is vascular rupture. Marfans has an upward lens dislocation, homocystinuria has a downward lens dislocation, and Ehlers-Danlos has hyperextensible skin and joint hyperextensibility. Marfans usually presents in teens, homocystinuria in children, and Ehlers-Danlos in young adults. Patient presentations: Marfans - scoliosis, long fingers, and caved in chest wall in a tall teen; Homocystinuria - developmental delay, long fingers, and tall stature in a child; Ehlers-Danlos - recurrent bruising, hyper extensible skin, and joint hyperextensibility in a young adult.

4.03 Large Vessel Vasculitis Rheumatology review for the USMLE Step 1 Exam Vasculitis is inflammation of blood vessels Vasculitis is split into three groups based on the size of blood vessels affected: large, medium, and small vessel vasculitis Large vessel vasculitis involves inflammation of the aorta and its main branches Two distinct large vessel vasculitidies: temporal (or giant cell) arteritis and takayasu arteritis Temporal (giant cell) arteritis primarily affects older women (>60) and the branches of the common carotid arteries Symptoms of temporal arteritis: jaw pain (jaw claudication), headaches, tenderness along temporal artery Complication of temporal arteritis: blindness Takayasu arteritis mostly affects young Asian women (

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), and Buerger disease (thromboangiitis obliterans) Polyarteritis nodosa affects middle-aged to older men and is idiopathic, but can be secondary to other diseases, including hepatitis B Histology findings show transmural inflammation with fibrinoid necrosis in early lesions, and string-of-beads sign in angiogram Symptoms include constitutional symptoms, abdominal pain and melena, and hypertension caused by damage to the renal arteries Kawasaki disease most commonly affects young Asian children, and is triggered by upper airway infections Symptoms include conjunctival injection, desquamating rash, cervical lymphadenopathy, strawberry tongue, and prolonged fever Kawasaki disease has a predilection for the coronary vessels, which can lead to aneurysm rupture and thrombi development Treatment for Kawasaki disease includes IVIG and aspirin to prevent complications

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 small vessel vasculitis include IgA vasculitis (Henoch-Schonlein Purpura), Granulomatosis with polyangiitis (Wegener Granulomatosis), Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome), Microscopic polyangiitis, and Behçet syndrome. IgA vasculitis is the most common in children, and anti-neutrophil cytoplasmic antibody + vasculitis are the most common in adults. IgA vasculitis is caused by the deposition of IgA immune complexes after an upper respiratory or GI tract infection, leading to palpable purpura, renal, GI, and joint involvement. It resolves on its own in a few weeks, and steroids and NSAIDs are used to reduce severity of symptoms.

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 cyclophosphamide and ifosfamide (chemotherapeutic agents) Muscle pain and rhabdomylitis from statin use (cholesterol lowering med) Tartive dyskinesia with antipsychotics  Fanconi syndrome from expired tetracyclines (antibiotics)

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 Leptospira interrogans are the three important species of spirochetes to know. Borrelia burgdorferi causes Lyme disease, which is spread from wildlife to ticks and then to humans. The deer tick, also known as ixodes scapularis, is associated with Borrelia burgdorferi, but deer are not the reservoir for the bacteria. Lyme disease presents in three stages: erythema migrans (bulls-eye rash), flu-like symptoms, Bell's palsy, myocarditis, transient myalgias, arthritis, and neurological symptoms like encephalopathy and peripheral neuropathy. Treponema pallidum causes syphilis, which presents in stages: primary (chancre), secondary (rash), latent, and tertiary (gummas, neurological symptoms). Leptospira interrogans causes leptospirosis (Weil's disease), which is spread from infected animal urine to humans through broken skin, mucous membranes, or ingestion. Leptospirosis presents with flu-like symptoms, jaundice, renal failure, and meningitis.

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 urealyticum. Mycoplasma pneumoniae causes atypical pneumonia and is spread through respiratory droplets. Symptoms include non-specific fever, headache, and sore throat, and diagnosis is done through PCR. Treatment is with macrolides, tetracyclines, and fluoroquinolones. Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma urealyticum cause genital infections and are acquired through sexual contact. They cause dysuria, urgency, urethral discharge, and pelvic pain. Diagnosis and treatment are similar to Mycoplasma pneumoniae with PCR and tetracyclines being the preferred treatment.  

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 include alcoholism and diabetes. Symptoms of klebsiella pneumonia include cough, fever, pleuritic chest pain, and shortness of breath, as well as rust-colored "currant jelly" sputum and cavitary lesions in the lungs. Klebsiella can also cause urinary tract infections, especially in hospital settings. Treatment typically involves antibiotics, but resistance testing may be necessary due to the bug's high antibiotic resistance  

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. Chlamydia trachomatis is the most common sexually transmitted infection in the US and causes genital tract infections, lymphogranuloma venereum, pelvic inflammatory disease, and reactive arthritis. Treatment for chlamydia trachomatis includes azithromycin or doxycycline, and ceftriaxone is often added to cover Neisseria gonorrhoeae. Chlamydia trachomatis can also infect neonates during delivery, causing conjunctivitis and pneumonia. Chlamydia pneumoniae causes community-acquired pneumonia spread through respiratory droplets. Chlamydia psittaci is associated with pet birds and also causes pneumonia.

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 of infections caused by P. aeruginosa are caused by the toxins it secretes, including phospholipase C, exotoxin A, and endotoxin. P. aeruginosa causes community-acquired infections such as hot tub folliculitis, otitis externa, lung infections in cystic fibrosis patients, osteomyelitis, and skin infections. It causes nosocomial infections such as ventilator-associated pneumonia and catheter-associated urinary tract infections. P. aeruginosa is associated with skin infections in burn victims

 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 attachment and easy motility Proteus mirabilis and Proteus vulgaris are the two main species that cause infections in humans Proteus mirabilis tends to cause hospital acquired UTIs and can cling to medical devices such as catheters, where it can infect the epithelium of the urinary tract and ascend up to the kidneys Proteus mirabilis expresses urease, converting urea to ammonia, which can cause the formation of struvite kidney stones Proteus vulgaris is less common than Proteus mirabilis and tends to be more difficult to treat due to drug-resistance plasmids Treatment for Proteus mirabilis infection depends on the type of infection, and for uncomplicated UTIs, patients can be given bactrim, while fluoroquinolones are given for pyelonephritis.

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 usually acquired through contaminated water. Non-typhoidal salmonella, such as salmonella enteritidis, are usually acquired through contaminated poultry or reptiles. Typhoidal salmonella cause high fever and a pink spotted rash, while non-typhoidal salmonella cause diarrhea, nausea, and vomiting. Both types of salmonella require large quantities of bacteria to make you sick, and supportive care is usually all that is required. Fluoroquinolones like ciprofloxacin are the go-to antibiotics for typhoidal salmonella.      

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 inhibit phagocytosis, the capsule contains F1 and V proteins and the injectosome injects Yersinia outer proteins. Yersinia pestis spreads through fleas, causing bubonic, pneumonic, or septicemic plague with symptoms like fever, chills, and swollen lymph nodes. Yersinia enterocolitica is spread through contaminated food or dog feces, causing enteric infection, and symptoms like diarrhea, abdominal pain, and vomiting. Yersinia pseudotuberculosis causes enteric disease, similar to Y. enterocolitica, and granulomatous lesions that look like tuberculosis. Yersinia pestis is rare with 500 cases reported since 1970, compared to Y. enterocolitica, which causes 100,000 cases each year

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 human GI tract, but some strains are pathogenic. Four pathogenic strains of E. coli are Entertoxigenic E. coli (ETEC), Enterohemorrhagic E. coli (EHEC), Enteroinvasive E. coli (EIEC), and Enteropathogenic E. coli (EPEC). ETEC causes watery diarrhea and is commonly found in food and water in areas with inadequate sanitation and is the most important cause of travelers' diarrhea. EHEC, also called Shiga toxin-producing E. coli (STEC), causes bloody diarrhea and is associated with contaminated food (spinach, sprouts, lettuce, fruit, undercooked beef). Shiga toxin produced by EHEC causes cell death in the GI tract and can lead to hemolytic uremic syndrome (HUS) in about 10% of cases. EIEC causes dysentery-like symptoms such as abdominal pain, fever, and bloody diarrhea. EPEC causes diarrhea, malnutrition, and growth retardation, especially in children. Extraintestinal infections include urinary tract infections (UTIs), neonatal sepsis, and pneumonia (incomplete list)  

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 for TB spread. Primary TB infection occurs when a person inhales infected droplets and the bacteria become dormant in a granuloma. Secondary TB infection occurs when the bacteria disseminate to surrounding tissues, affecting various parts of the body. Symptoms of active TB include night sweats, weight loss, fever, and cough (sometimes with blood). TB can present with various symptoms, making it known as the "great imitator." Diagnosis methods include chest X-rays, sputum acid-fast staining, and real-time nucleic acid amplification. Chest X-rays showing cavitary lesions and positive acid-fast staining are indicative of TB. Treatment involves a 4-drug combination of rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE) for an extended period of time (2-4 months) to get rid of the infection.

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 resolution Most commonly associated with strep pneumoniae, also caused by Legionella and Klebsiella Bronchopneumonia is an infection of the bronchi that leads to diffuse infection of adjacent alveoli Causative organisms include strep pneumoniae, klebsiella, H influenza, and staph aureus Interstitial pneumonia is an ongoing infection in the interstitial areas of alveolar walls Causative organisms tend to be different compared to other types of pneumonia and include Mycoplasma pneumoniae, Legionella, chlamydophilia bugs, Coxiella burnetti, and some viruses (influenza and RSV) On chest X-ray, lobar pneumonia shows haziness in a single lobe with sharp demarcation, while bronchopneumonia and interstitial pneumonia show more diffuse haziness throughout the lungs Interstitial pneumonia tends to be more indolent, and patients may have not so good looking lungs on chest X-ray but are up and walking around (walking pneumonia).

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 most common cause, as well as iatrogenic causes like transthoracic needle aspiration and central venous catheterization. Spontaneous pneumothorax occurs without any trauma and can be classified as primary (no underlying lung disease) or secondary (with underlying lung disease). Smoking greatly increases the risk for spontaneous pneumothorax, especially in tall men with Marfan's syndrome or Ehlers-Danlos syndrome. Tension pneumothorax is a more emergent and dangerous type of pneumothorax, where air enters the pleural cavity but cannot exit, causing pressure to build up and compress nearby structures like the lungs, blood vessels, and heart.

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 protein and lactate dehydrogenase content. Pleural exudates are commonly caused by lung infections, lung cancer, and inflammatory diseases. Pleural transudates are caused by increased hydrostatic pressures or decreased oncotic pressure within the lung capillaries that force fluid into the pleural cavity. Transudative effusions are not caused by inflammation, so lactate dehydrogenase content is not expected to be high. Proteins are too big to move between cells, so transudative effusions have low protein content.

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, megakaryocytes, and the growth factors platelet derived growth factor (PDGF) and vascular endothelial growth factors (VEGF). Diseases associated with digital clubbing include lung cancer, cystic fibrosis, idiopathic pulmonary fibrosis, bronchiectasis, and an empyema. Digital clubbing is usually not associated with asthma or COPD.

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 presents with obesity, daytime sleepiness, and symptoms consistent with obstructive sleep apnea Diagnosis confirmed by arterial blood gas Short term treatment with positive airway pressure therapy Long term treatment involves lifestyle changes to lose weight CPAP machine supplies positive pressure to reduce CO2 build up Weight loss relieves symptoms by reducing excess weight on lungs.

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 the airway collapses during sleep, and it is more likely to be associated with snoring, gasping, and choking. Central sleep apnea occurs when breathing cessations are caused by decreased central nervous system respiratory drive, and it is more likely to be associated with Cheyne-Stokes respirations. Sleep apnea can cause hypertension, pulmonary hypertension, cardiac arrhythmias, and even sudden death. The most common symptom patients will present with is daytime sleepiness, and obesity is associated with obstructive sleep apnea. Diagnosis relies heavily on testing, and the gold standard for diagnosis of sleep apnea is a sleep study (a laboratory polysomnography).  

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 blood pressure caused by an underlying condition. Common underlying conditions for secondary pulmonary hypertension include heart failure, chronic thromboembolic disease, lung disease, and autoimmune disease. Pulmonary hypertension can lead to right heart failure and eventually death. Treatment for pulmonary hypertension involves treating the underlying disease and using drugs such as PDE-5 inhibitors, endothelin receptor antagonists, and prostacyclin to dilate the vessels in the lungs and lower the pressure within the pulmonary vessels.