# USMLE KNOWLEDGE

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USMLE KNOWLEDGE

## 2. BASIC SCIENCES

### 2.1. BIOSTATISTICS

2.1.1. STATISTICAL SIGNIFICANCE

2.1.1.1. BASIC TERMS

2.1.1.2. CONFIDENCE INTERVAL

2.1.1.2.1. IT MEASURES HOW RELIABLE AN ESTIMATE IS

2.1.1.2.2. USED TO CALCULATE THE PROBABILITY THAT THE DIFFERENT MEANS BETWEEN 2 GROUPS IS REAL

2.1.1.3. T-TEST

2.1.1.3.1. IT REQUIRES NORMALLY DISTRIBUTED, CONTINUOUS MEASUREMENTS

2.1.1.4. CHI-SQUARED TEST

2.1.1.4.1. SIMILAR TO T-TEST, EXCEPT IT IS USED FOR CATEGORICAL MEASURES

2.1.1.4.2. ANOVA (ANALYSIS OF VARIANCE)

2.1.1.4.3. USED TO CALCULATE WHETHER OR NOT A DIFFERENCE BETWEEN TWO PERCENTAGES/PROPORTIONS (NOT MEANS) IS REAL

2.1.2. STATISTICAL DISTRIBUTIONS

2.1.2.1. CONTINUOUS PROBABILITY DISTRIBUTION, WHICH IS A FUNCTION THAT PREDICTS THE PROBABILITY THAT AN OBSERVATION WILL FALL ON A GIVEN VALUE

2.1.2.2. THERE ARE VARIOUS PATTERNS OF DISTRIBUTION

2.1.2.2.1. NORMAL DISTRIBUTION

2.1.2.2.2. SKEWED DISTRIBUTION

2.1.2.3. STATISTICAL CHARACTERISTICS

2.1.2.3.1. MEAN

2.1.2.3.2. MODE

2.1.2.3.3. MEDIAN

2.1.3. HYPOTHESES AND ERROR TYPES

2.1.4. INCIDENCE AND PREVALENCE

2.1.5. SPECIFICITY, SENSITIVITY, PPV, NPV

2.1.6. ABSOLUTE RISK REDUCTION

2.1.7. NUMBER NEEDED TO TREAT OR HARM

2.1.8. PRECISION AND ACCURACY

2.1.9. VALIDITY

2.1.10. INTERNAL VALIDITY

2.1.11. EVALUATING RISK

2.1.12. ATTRIBUTABLE RISK

### 2.2. BIOCHEMISTRY

2.2.1. GENETICS

2.2.1.1. CYSTIC FIBROSIS

2.2.1.1.1. AN AUTOSOMAL RECESSIVE DEFECT IN A TRANSMEMBRANE CHLORIDE CHANNEL (USUALLY A DELETION OF Phe508) RESULTS IN THICKENED MUCUS SECRETIONS, SEVERELY AFFECTING FUNCTION OF THE PANCREATIC, PULMONARY, AND REPRODUCTIVE SYSTEMS

2.2.1.1.2. MOST COMMON LETHAL GENETIC DISEASE IN WHITES

2.2.1.1.3. GENE: CFTR (A CHLORIDE CHANNEL) ON CHROMOSOME 7

2.2.1.1.4. DIAGNOSIS

2.2.1.1.5. DEFECTIVE GENE RESULTS IN:

### 2.3. IMMUNOLOGY

2.3.1. IMMUNE DEFICIENCIES

2.3.1.1. DIGEORGE SYNDROME (THYMIC HYPOPLASIA)

2.3.1.1.1. DIGEORGE SYNDROME RESULTS FROM FAILURE OF DEVELOPMENT OF THE 3RD AND 4TH PHARYNGEAL POUCHES, WHICH GIVE RISE TO THE THYMUS AND PARATHYROID GLANDS

2.3.1.1.2. CATCH-22 IS A MNEMONIC USED TO DESCRIBE THE FEATURES OF DIGEORGE SYNDROME:

2.3.1.1.3. THE MOST COMMON CAUSE OF DEATH IN DIGEORGE SYNDROME IS CONGENITAL HEART DISEASE

2.3.2. IMMUNOSUPPRESSANTS

2.3.2.1. TRANSPLANT REJECTION

2.3.2.1.1. HYPERACUTE REJECTION OCCURS WHEN THERE IS THE PRESENCE OF PREFORMED ANTIBODIES AGAINST THE DONOR’S HLA OR ABO ANTIGENS AT TIME OF TRANSPLANTATION, LEADING TO REJECTION OF THE TRANSPLANT WITHIN MINUTES

2.3.2.1.2. ACUTE REJECTION IS A COMBINATION OF A TYPE IV AND TYPE II HYPERSENSITIVITY REACTION

2.3.2.1.3. CHRONIC REJECTION IS CHARACTERIZED BY EPISODIC BOUTS OF REJECTION OCCURRING MONTHS TO YEARS AFTER TRANSPLANTATION

2.3.2.1.4. GRAFT VS. HOST DISEASE IS A COMMON COMPLICATION OF ALLOGENEIC BONE MARROW TRANSPLANTATION IN WHICH FUNCTIONAL IMMUNE CELLS IN THE DONOR MARROW RECOGNIZE THE RECIPIENT AS FOREIGN AND MOUNT AN IMMUNOLOGIC ATTACK AGAINST THE RECIPIENT

### 2.4. PATHOLOGY

2.4.1. RESPONSES TO INJURY

2.4.1.1. ACUTE INFLAMMATION IS THE INNATE IMMUNITY’S IMMEDIATE RESPONSE TO ANY INSULT CHARACTERIZED BY MOST PROMINENTLY BY NEUTROPHILS, AS WELL AS EOSINOPHILS AND ANTIBODIES LASTING FOR MINUTES TO DAYS

2.4.1.1.1. EOSINOPHILS ARE THE PREDOMINANT INFLAMMATORY CELLS IN ALLERGIC REACTIONS AND PARASITIC INFESTATIONS

2.4.1.2. THE CARDINAL SIGNS OF INFLAMMATION ARE:

2.4.1.2.1. RUBOR (REDNESS)

2.4.1.2.2. DOLOR (PAIN)

2.4.1.2.3. CALOR (HEAT)

2.4.1.2.4. TUMOR (SWELLING)

2.4.1.2.5. FUNCTION LAESA (LOSS OF FUNCTION)

2.4.1.3. PROSTAGLANDINS (PG) I2, D2, AND E2 CAUSE VASODILATION AND INCREASED VASCULAR PERMEABILITY

2.4.1.4. FLUID EXUDATION: VASCULAR PERMEABILITY INCREASES, FACILITATING EXTRAVASATION OF IMMUNE CELLS AND NUTRIENTS AND THE CARRYING AWAY OF TOXIC METABOLITES OF THE INFLAMMATORY RESPONSE, RESULTING IN NET FLUID EXUDATION

2.4.1.4.1. BEGINS WITH A BRIEF PERIOD OF ARTERIOLAR VASOCONSTRICTION FOLLOWED SHORTLY BY DILATATION OF ARTERIOLES, CAPILLARIES, AND POSTCAPILLARY VENULES

2.4.1.4.2. THE RESULTING INCREASE IN BLOOD FLOW TO THE AFFECTED AREA CLINICALLY MANIFESTS AS REDNESS AND INCREASED WARMTH

2.4.1.4.3. FLUID EXUDATION MAY ALSO BE CAUSED BY ENDOTHELIAL INJURY OR CONTRACTION OF ENDOTHELIAL CELLS IN POSTCAPILLARY VENULES, WITH WIDENING OF INTERENDOTHELIAL GAPS

2.4.1.4.4. INCREASED CAPILLARY PERMEABILITY RESULTS IN LEAKAGE OF PROTEINACEOUS FLUID CAUSING EDEMA

2.4.1.5. NEUTROPHILS ENTER TISSUE VIA THE LEUKOCYTE ACTIVATION PATHWAY AND PARTICIPATE IN PHAGOCYTOSIS, DEGRANULATION, AND INFLAMMATORY MEDIATOR RELEASE

2.4.1.6. FOLLOWING NEUTROPHILS (1-2 DAYS LATER), MACROPHAGES MANAGE THE NEXT STEP OF THE INFLAMMATORY PROCESS, WHICH CAN BE ANY OF THE FOLLOWING:

2.4.1.6.1. RESOLUTION AND HEALING

2.4.1.6.2. CONTINUED ACUTE INFLAMMATION

2.4.1.6.3. ABSCESS FORMATION

2.4.1.6.4. CHRONIC INFLAMMATION

2.4.1.7. CONTINUED ACUTE INFLAMMATION RESULTS WHEN MACROPHAGES RELEASE INTERLEUKIN (IL)-8 LEADING TO RECRUITMENT OF MORE NEUTROPHILS AND MORE PUS FORMATION

2.4.1.8. RESOLUTION AND HEALING IS ACHIEVED WHEN MACROPHAGES PRODUCE ANTI-INFLAMMATORY CYTOKINES SUCH AS TGFΒ AND IL-10

2.4.1.9. ABSCESS FORMATION IS CHARACTERIZED BY FIBRIN-LINED CAVITY FILLED WITH PUS (NEUTROPHILS, MONOCYTE/MACROPHAGES, AND LIQUIFIED CELLULAR DEBRIS)

2.4.1.10. MACROPHAGES MAY PRESENT ANTIGEN TO ACTIVATE LYMPHOCYTES (CD4+ HELPER T CELLS) LEADING TO CHRONIC INFLAMMATION

2.4.1.11. ACUTE-PHASE REACTANTS ARE FACTORS WHOSE SERUM CONCENTRATION SIGNIFICANTLY CHANGES IN RESPONSE TO INFLAMMATION

2.4.1.11.1. IN RESPONSE TO INJURY, MACROPHAGES AND OTHER INFLAMMATORY CELLS SECRETE INTERLEUKINS IL-1, IL-6 AND TNF-α AND IFN-γ AND THE LIVER RESPONDS BY SIGNIFICANTLY INCREASING OR DECREASING THE PRODUCTION OF ACUTE-PHASE REACTANTS

2.4.1.12. THE FOLLOWING ACUTE PHASE REACTANTS ARE ELEVATED IN THE SERUM IN RESPONSE TO INFLAMMATION:

2.4.1.12.1. C-REACTIVE PROTEIN

2.4.1.12.2. FERRITIN

2.4.1.12.3. FIBRINOGEN

2.4.1.12.4. HEPCIDIN

2.4.1.12.5. SERUM AMYLOID A

2.4.1.13. THE FOLLOWING ACUTE-PHASE REACTANTS ARE REDUCED IN THE SERUM IN RESPONSE TO INFLAMMATION:

2.4.1.13.1. ALBUMIN

2.4.1.13.2. TRANSFERRIN

## 4. HEMATOLOGIC CHANGES THAT OCCUR DURING PREGNANCY INCLUDE AN INCREASE IN:

### 4.1. PLASMA VOLUME

4.1.1. PREGNANCY LEADS TO A 50% INCREASE IN PLASMA VOLUME, BUT ONLY A 30% INCREASE IN RBC VOLUME, WHICH RESULTS IN DILUTIONAL ANEMIA

4.1.2. CHOLESTEROL SYNTHESIS DIORDERS

## 8. INBORN ERRORS OF METABOLISM

### 8.4. MAPLE SYRUP URINE DISEASE

8.4.1. INHERITED DISORDER OF BRANCHED-CHAIN AMINO ACID METABOLISM IN WHICH ELEVATED LEVELS OF LEUCINE, ISOLEUCINE, VALINE, AND CORRESPONDING OXOACIDS ACCUMULATE IN THE BODY FLUIDS

8.4.2. DEFINITION

8.4.2.1. DEFICIENCY OF BRANCHED CHAIN KETOACID DEHYDROGENASE

8.4.3. SIGNS/SYMPTOMS

8.4.3.1. POOR FEEDING, VOMITING IN FIRST WEEK OF LIFE, PROCEEDING TO LETHARGY AND COMA

8.4.3.2. ALTERNATING HYPERTONICITY AND FLACCIDITY, CONVULSIONS, HYPOGLYCEMIA

8.4.3.3. NOTE THAT IF MOM HAS BEEN TAKING FENUGREEK TO BOOST MILK PRODUCTION, THIS CAN LEAD TO A SIMILAR SWEET SMELL IN BOTH MOM AND BABY

8.4.3.3.1. ODOR OF MAPLE SYRUP IN URINE, SWEAT, CERUMEN

8.4.4. DIAGNOSIS/SCREENING

8.4.4.1. URINE PRECIPITANT TEST AND NEUROIMAGING IN THE ACUTE STATE CAN SHOW CEREBRAL EDEMA

8.4.4.2. IT IS NORMALLY INCLUDED IN THE NEWBORN SCREENING FOR METABOLIC DISORDERS

8.4.5. TREATMENT

8.4.5.1. PATIENT SHOULD BE ON A LOW BRANCHED-CHAIN AMINO ACID DIET

8.4.5.2. FREQUENT SERUM LEVEL MONITORING

8.4.5.3. IN THE ACUTE STAGE INTRAVENOUS ADMINISTRATION OF AMINO ACIDS OTHER THAN BRANCHED CHAIN AMINO ACIDS

8.4.5.4. EMERGENT HEMODIALYSIS OR PERITONEAL DIALYSIS IF PATIENT IS ACIDOTIC.

8.4.5.5. LIVER TRANSPLANTATION CAN DEFINITIVELY TREAT MAPLE SYRUP URINE DISEASE

## 9. CHARACTERISTICALLY, CELIAC DISEASE MANIFESTS DURING INFANCY AND BEFORE SCHOOL AGE

### 9.1. IN THE CLASSIC FORM OF CHILDHOOD CELIAC DISEASE, SYMPTOMS AND SIGNS OF MALABSORPTION BECOME OBVIOUS WITHIN SOME MONTHS OF STARTING A GLUTEN-CONTAINING DIET

9.1.1. CHILDREN MAY PRESENT WITH FAILURE TO THRIVE, AND PROXIMAL MUSCLE WASTING MAY BE SEEN

9.1.1.1. GASTROINTESTINAL SYMPTOMS OF CELIAC SPRUE INCLUDE:

9.1.1.1.1. FOUL-SMELLING DIARRHEA

9.1.1.1.2. ABDOMINAL PAIN

9.1.1.1.3. WEIGHT LOSS

9.1.1.1.4. BLOATING

9.1.1.1.5. FATIGUE

9.1.1.1.6. STEATORRHEA

9.1.1.2. EXTRAINTESTINAL MANIFESTATIONS OF CELIAC SPRUE INCLUDE:

9.1.1.2.1. ANEMIA

9.1.1.2.2. NEUROLOGIC SYMPTOMS (MOTOR WEAKNESS, PARASTHESIAS)

9.1.1.2.3. DERMATITIS HERPETIFORMIS

9.1.1.2.4. HORMONAL DISORDERS (AMENORRHEA/INFERTILITY IN WOMEN, IMPOTENCE/INFERTILITY IN MEN)

## 10. STEP 2 CK

### 10.1. INTERNAL MEDICINE

10.1.1. DERMATOLOGY

10.1.1.1. STEVEN-JOHNSON SYNDROME

10.1.1.1.1. STEVENS-JOHNSON SYNDROME (SJS) IS A SEVERE FORM OF ERYTHEMA MULTIFORME INVOLVING MUCOUS MEMBRANES AND SEVERE PLAQUE FORMATION. IT IS AN IMMUNE-MEDIATED HYPERSENSITIVITY REACTION THAT LEADS TO NECROSIS AND SLOUGHING OF THE EPIDERMIS

10.1.1.1.2. STEVENS-JOHNSON SYNDROME REPRESENTS THE SAME PROCESS AS TOXIC EPIDERMAL NECROLYSIS (TEN)

10.1.1.1.3. THERE ARE 4 ETIOLOGIC CATEGORIES FOR SJS:

10.1.1.1.4. SJS PRESENTS WITH A 2-3 DAY PRODROMAL PERIOD OF FEVER AND FLU-LIKE SYMPTOMS PRIOR TO THE DEVELOPMENT OF MUCOCUTANEOUS LESIONS

10.1.1.1.5. IN A PATIENT’S FIRST DRUG-EXPOSURE RELATED CASE OF SJS, THE DRUG EXPOSURE TYPICALLY OCCURS ONE TO THREE WEEKS BEFORE THE DEVELOPMENT OF SYMPTOMS

10.1.1.1.6. THE TIME COURSE FROM PRODROME UNTIL HOSPITAL DISCHARGE RANGES BETWEEN TWO TO FOUR WEEKS

10.1.1.1.7. BLISTERING AND SWELLING OF THE ORAL CAVITY IS ALSO SEEN IN PATIENTS WITH SJS

10.1.1.1.8. THERE ARE NO SPECIFIC DIAGNOSTIC STUDIES FOR SJS, BUT A HISTORY SUGGESTIVE OF DRUG EXPOSURE/ILLNESS, POSITIVE CLINICAL SYMPTOMS, AND A SKIN BIOPSY CAN HELP CONFIRM CLINICAL SUSPICION

10.1.1.1.9. ON PHYSICAL EXAMINATION A PATIENT WITH SJS WILL TYPICALLY HAVE AN ERYTHEMATOUS RASH WHICH MAY HAVE THE APPEARANCE OF A TARGET

10.1.1.1.10. OTHER SIGNS THAT RAISE CONCERN OF SJS INCLUDE:

10.1.1.1.11. LESIONS TYPICALLY START ON THE FACE AND THORAX BEFORE SPREADING, AND SPARE THE SCALP

10.1.1.1.12. AFTER A FEW DAYS, THE SKIN RASHES PROGRESSES TO VESICLES AND BULLAE, AND THE SKIN BEGINS TO SLOUGH

10.1.1.1.13. MUCOUS MEMBRANES ARE ALMOST ALWAYS INVOLVED IN SJS, INCLUDING THE ORAL MUCOSA (INCLUDING TONGUE), CONJUNCTIVA, URETHRA, AND PULMONARY MUCOSA

10.1.1.1.14. SKIN BIOPSIES ARE FAIRLY SPECIFIC AND TYPICALLY SHOW LYMPHOCYTES WITHIN PERIVASCULAR STRUCTURES AND FULL THICKNESS EPIDERMAL DETACHMENT WITH A NORMAL IMMUNOFLUORESCENCE

10.1.1.1.15. THE MORTALITY RATE OF SJS IS ABOUT 10%

10.1.1.1.16. BECAUSE THE MOST COMMON CAUSE OF SJS IS A REACTION TO MEDICATION, THE MOST IMPORTANT FIRST STEP IN TREATMENT IS TO STOP THE OFFENDING MEDICATION

10.1.2. GASTROENTEROLOGY

10.1.2.1. CELIAC SPRUE

10.1.2.1.1. CELIAC SPRUE (I.E. GLUTEN INTOLERANCE) IS AN IMMUNE-MEDIATED DESTRUCTION OF THE MUCOSA OF THE JEJUNUM

10.1.2.1.2. PATHOGENESIS INVOLVES THE INGESTION AND BIOCHEMICAL BREAKDOWN OF GLUTEN (FOUND IN WHEAT, BARLEY, RYE), AND THE SUBSEQUENT AUTOIMMUNE INFLAMMATORY REACTION TO GLIADIN, AN ALCOHOL-SOLUBLE FRACTION OF GLUTEN

10.1.2.1.3. CELIAC SPRUE HAS A STRONG HEREDITARY COMPONENT--HLA HAPLOTYPES DQ2 AND DQ8 ARE STRONGLY LINKED TO DISEASE

10.1.2.1.4. OTHER THAN DISEASE IN A FIRST-DEGREE RELATIVE, RISK FACTORS FOR CELIAC SPRUE INCLUDE:

10.1.2.1.5. FOR SUSPECTED CELIAC DISEASE, THE BEST INITIAL TEST IS A SERUM LEVEL OF IMMUNOGLOBULIN A ANTI-TISSUE TRANSGLUTAMINASE ANTIBODY (IGA TTG)

10.1.2.1.6. OTHER USEFUL LAB TESTS INCLUDE:

10.1.2.1.7. THE GOLD STANDARD IN DIAGNOSING CELIAC SPRUE IS A DUODENAL BIOPSY, WHICH SHOWS:

10.1.2.1.8. RADIOGRAPHIC STUDIES MAY BE USEFUL IN UNTREATED CELIAC SPRUE

10.1.2.1.9. THE PRIMARY TREATMENT OF CELIAC SPRUE IS THE AVOIDANCE OF GLUTEN-CONTAINING PRODUCTS, SUCH AS WHEAT, BARLEY AND RYE

10.1.2.1.10. CELIAC SPRUE MAY RESULT IN THE FOLLOWING LONG TERM COMPLICATIONS:

10.1.2.1.11. TROPICAL SPRUE

10.1.2.2. HEPATIC ENCEPHALOPATHY

10.1.2.2.1. IT OCCURS WHEN AMMONIA CLEARANCE IS COMPROMISED (DUE TO CHRONIC LIVER DYSFUNCTION) AND CONSEQUENTLY BUILDS UP AND CROSSES INTO THE CNS

10.1.2.2.2. PATIENTS PRESENT WITH

10.1.2.2.3. DIAGNOSIS IS BASED ON SERUM AMMONIA LEVELS, AND EVALUATING LIVER FUNCTION VIA THE FOLLOWING:

10.1.2.2.4. TREATMENT IS AIMED AT AMMONIA REDUCTION, WHICH CAN BE ACHIEVED THROUGH:

10.1.3. PULMONOLOGY

10.1.3.1. CYSTIC FIBROSIS

10.1.3.1.1. CYSTIC FIBROSIS (CF) IS AN AUTOSOMAL RECESSIVE INHERITED DISEASE CAUSED BY A MUTATION IN THE GENE CODING FOR A COMPLEX CHLORIDE CHANNEL

10.1.3.1.2. CF IS CAUSED BY MUTATIONS IN THE GENE THAT CODES FOR THE CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR (CFTR) PROTEIN

10.1.3.1.3. CF IS THE MOST COMMON LIFE-SHORTENING AUTOSOMAL RECESSIVE DISEASE IN CAUCASIANS, AND OCCURS ONCE IN EVERY 2000 TO 3000 LIVE BIRTHS

10.1.3.1.4. SYMPTOMS OF CYSTIC FIBROSIS USUALLY BEGIN TO PRESENT IN EARLY CHILDHOOD AND COMMONLY INCLUDE MECONIUM ILEUS, RESPIRATORY SYMPTOMS, AND FAILURE TO THRIVE

10.1.3.1.5. THE MAJORITY OF CYSTIC FIBROSIS CASES IN THE UNITED STATES ARE NOW DETECTED THROUGH NEWBORN SCREENING

10.1.3.1.6. IN ADULTS AND OLDER CHILDREN, TWO CRITERIA MUST BE MET FOR THE DIAGNOSIS OF CF:

10.1.3.1.7. FINDINGS CONSISTENT WITH CYSTIC FIBROSIS ON PHYSICAL EXAM INCLUDE WHEEZING, INCREASED ANTEROPOSTERIOR DIAMETER OF THE THORAX, DIGITAL CLUBBING, AND POOR WEIGHT GAIN/FAILURE TO THRIVE

10.1.3.1.8. WHILE CHEST X-RAY IS NOT USED FOR DIAGNOSIS, THE CHEST X-RAYS OF CYSTIC FIBROSIS PATIENTS MAY SHOW HYPERINFLATION, BRONCHIECTASIS, CYST FORMATION, AND FLATTENING OF THE DIAPHRAGMS

10.1.3.1.9. THE COMPLICATIONS OF CYSTIC FIBROSIS ARE MANY AND VARIED

10.1.3.1.10. TREATMENT OF CF VARIES BASED ON THE SPECIFIC MUTATION AND SEVERITY OF DISEASE, BUT TYPICALLY INCLUDES:

10.1.3.1.11. CYSTIC FIBROSIS LUNG DISEASE EXACERBATIONS ARE TYPICALLY TREATED WITH AGGRESSIVE CHEST PHYSIOTHERAPY AND ADDITIONAL ANTIBIOTICS

### 10.2. OBSTETRICS

10.2.1. A HEALTHY PREGNANCY

10.2.1.1. PHYSIOLOGIC CHANGES OF PREGNANCY

10.2.1.1.1. CARDIOVASCULAR CHANGES THAT OCCUR DURING PREGNANCY INCLUDE AN INCREASE IN CARDIAC OUTPUT AND A DECREASE IN BLOOD PRESSURE, BOTH OF WHICH IMPROVE UTEROPLACENTAL PERFUSION

10.2.1.1.2. RESPIRATORY

10.2.1.1.3. RENAL CHANGES THAT OCCUR DURING PREGNANCY INCLUDE AN INCREASE IN RENAL BLOOD FLOW, INCREASED RENAL SIZE, AND URETERAL DILATION

10.2.1.1.4. ENDOCRINE

10.2.1.1.5. HEMATOLOGY

10.2.1.1.6. GASTROINTESTINAL CHANGES THAT OCCUR DURING PREGNANCY INCLUDE DELAYED STOMACH EMPTYING AND A DECREASE IN LOWER ESOPHAGEAL SPHINCTER TONE

10.2.1.1.7. LOW RISK ACTIVITIES THAT CAN CONTINUE DURING PREGNANCY INCLUDE:

### 10.3. PEDIATRICS

10.3.1. HEALTH SUPERVISION

10.3.1.1. OVERVIEW OF IMMUNIZATIONS

10.3.1.1.1. THERE ARE TWO MAIN TYPES OF VACCINES: LIVE ATTENUATED VACCINES AND INACTIVATED VACCINES

10.3.1.1.2. THE CENTER FOR DISEASE CONTROL (CDC) DISTRIBUTES AN ANNUAL IMMUNIZATION SCHEDULE FOR CHILDREN AND ADOLESCENTS, AS WELL AS A CATCH-UP SCHEDULE

10.3.1.1.3. IN GENERAL, A VACCINE IS CONTRAINDICATED IF AN ANAPHYLACTIC REACTION TO THAT VACCINE IS EXPERIENCED AND SHOULD BE DISCONTINUED

10.3.2. NEONATOLOGY

10.3.2.1. NEWBORN EXAM - SKIN

10.3.2.2. NEWBORN EXAM - CRANIOFACIAL

10.3.2.3. NEWBORN EXAM - NECK, CHEST, ABDOMINAL, GENITAL, EXTREMITIES

10.3.3. NEONATOLOGY (NICU)

10.3.3.1. NEONATAL RESPIRATORY DISTRESS SYNDROME (NRDS)

10.3.4. NORMAL GROWTH AND DEVELOPMENT

10.3.4.1. NEWBORN GROWTH RATE

10.3.4.2. NEWBORN CALORIC REQUIREMENT

10.3.4.3. BREAST FEEDING VS BREAST MILK JAUNDICE

10.3.4.3.1. BREAST FEEDING JAUNDICE ALSO KNOWN AS “NOT ENOUGH MILK JAUNDICE” IS AN ABNORMAL UNCONJUGATED HYPERBILIRUBINEMIA DURING THE FIRST WEEK OF LIFE RESULTING FROM DECREASED ENTERAL INTAKE AND INCREASED ENTEROHEPATIC CIRCULATION OF BILIRUBIN. THERE IS NO ASSOCIATED INCREASE IN BILIRUBIN PRODUCTION

10.3.4.3.2. BREAST MILK JAUNDICE IS NORMAL EXTENSION OF PHYSIOLOGIC JAUNDICE OF THE NEWBORN, UNCONJUGATED HYPERBILIRUBINEMIA IN THE FIRST WEEK OF LIFE. IT BEGINS AFTER THE FIFTH DAY OF LIFE AND CONTINUES FOR SEVERAL WEEKS

10.3.4.3.3. TAKE HOME POINT:

10.3.4.4. FORMULA TYPES

10.3.4.5. GROWTH CHARTS

10.3.4.6. INTRAUTERINE FACTORS FOR GROWTH

10.3.4.7. TEETH

10.3.4.8. APPROACH TO A CHILD WITH MICROCEPHALY

10.3.4.9. FAILURE TO THRIVE

10.3.4.10. DEVELOPMENTAL MILESTONES: 1 MONTH

10.3.4.11. DEVELOPMENTAL MILESTONES: 2 MONTHS

10.3.4.12. DEVELOPMENTAL MILESTONES: 4 MONTHS

10.3.4.13. DEVELOPMENTAL MILESTONES: 6 MONTHS

10.3.4.14. DEVELOPMENTAL MILESTONES: 9 MONTHS

10.3.4.15. DEVELOPMENTAL MILESTONES: 12 MONTHS

10.3.4.16. DEVELOPMENTAL MILESTONES: 2 YEARS

10.3.4.17. DEVELOPMENTAL MILESTONES: 3 YEARS

10.3.4.18. DEVELOPMENTAL MILESTONES: 4 YEARS

10.3.4.19. DEVELOPMENTAL MILESTONES: 5 YEARS

10.3.4.20. PRIMITIVE REFLEXES

10.3.4.21. DEVELOPMENTAL DELAY

10.3.4.22. LEARNING DISABILITIES

10.3.4.23. SLEEP

10.3.4.24. FLUID MANAGEMENT OF THE PEDIATRIC PATIENT

10.3.4.25. BREAST FEEDING

10.3.4.25.1. THE AMERICAN ACADEMY OF PEDIATRICS (AAP) AND WORLD HEALTH ORGANIZATION (WHO) STRONGLY ADVOCATE BREASTFEEDING AS THE PREFERRED FEEDING FOR ALL INFANTS AND SHOULD BE INITIATED SOON AFTER BIRTH

10.3.4.25.2. STAGES OF LACTOGENESIS

10.3.4.25.3. BENEFITS FOR THE INFANT

10.3.4.25.4. BENEFITS FOR THE MOTHER

10.3.4.25.5. COMPLICATIONS

10.3.4.25.6. CONTRAINDICATIONS

10.3.4.25.7. POSSIBLE VITAMIN DEFICIENCIES IN BREAST FED INFANTS REQUIRES THAT THESE INFANTS RECEIVE:

10.3.4.26. APPROACH TO A CHILD WITH MACROCEPHALY

10.3.4.27. DEVELOPMENTAL MILESTONES: 18 MONTHS

10.3.5. PEDIATRIC CARDIOLOGY

10.3.5.1. TRANSPOSITION OF THE GREAT VESSELS

10.3.5.2. ATRIAL SEPTAL DEFECT (ASD)

10.3.5.3. AORTIC COARCTATION

10.3.5.4. PATENT DUCTUS ARTERIOSUS

10.3.5.5. TETRALOGY OF FALLOT

10.3.5.6. VENTRICULAR SEPTAL DEFECT (VSD)

10.3.5.7. HYPOPLASTIC LEFT HEART SYNDROME

10.3.5.8. EBSTEIN'S ANOMALY

10.3.5.9. TRUNCUS ARTERIOSUS

10.3.5.10. TOTAL ANOMALOUS PULMONARY VENOUS RETURN

10.3.5.11. TRICUSPID ATRESIA

10.3.5.12. PULMONARY ATRESIA

10.3.5.13. PEDIATRIC AORTIC STENOSIS

10.3.6. PEDIATRIC DERMATOLOGY

10.3.6.1. STEVENS-JOHNSON SYNDROME/TOXIC EPIDERMAL NECROLYSIS

10.3.7. PEDIATRIC ENDOCRINOLOGY

10.3.7.1. CONGENITAL HYPOTHYROIDISM (CRETINISM)

10.3.7.2. PRECOCIOUS PUBERTY

10.3.7.3. MCCUNE ALBRIGHT SYNDROME

10.3.8. PEDIATRIC GASTROENTEROLOGY

10.3.8.1. ESOPHAGEAL ATRESIA

10.3.8.2. ESOPHAGEAL FOREIGN BODY

10.3.8.3. PEPTIC ULCER

10.3.8.4. PYLORIC STENOSIS

10.3.8.5. DUODENAL ATRESIA

10.3.8.6. INTUSSUSCEPTION

10.3.8.7. MECKEL'S DIVERTICULUM

10.3.8.8. CONSTIPATION

10.3.8.9. HIRSCHSPRUNG'S MEGACOLON

10.3.8.10. IMPERFORATE ANUS

10.3.8.11. GILBERT SYNDROME

10.3.8.12. CRIGLER-NAJJAR SYNDROME

10.3.8.13. ALAGILLE SYNDROME

10.3.8.14. ZELLWEGER SYNDROME

10.3.8.15. REYE SYNDROME

10.3.8.16. A1-ANTITRYPSIN DEFICIENCEY

10.3.8.17. HEPATOBLASTOMA

10.3.8.18. BACTERIAL ENTERITIS/ENTEROPATHOGENS

10.3.8.19. MALROTATION

10.3.8.20. CONSTIPATION

10.3.9. PEDIATRIC HEMATOLOGY & ONCOLOGY

10.3.9.1. PEDIATRIC SICKLE CELL ANEMIA

10.3.9.2. HEMOLYTIC DISEASE OF THE NEWBORN (ERYTHROBLASTOSIS FETALIS)

10.3.9.3. FANCONI ANEMIA

10.3.9.4. ANEMIAS IN THE PEDIATRIC POPULATION

10.3.9.5. INHERITED HEMATOLOGIC DISORDERS

10.3.10. PEDIATRIC INFECTIOUS DISEASE

10.3.10.1. BOTULISM

10.3.10.2. MENINGOCOCCEMIA

10.3.10.3. OCCULT BACTEREMIA IN CHILDREN

10.3.10.4. SEPSIS IN CHILDREN

10.3.10.5. HIV

10.3.10.6. RUBEOLA

10.3.10.7. RUBELLA

10.3.10.8. ERYTHEMA INFECTIOSUM

10.3.10.9. SCARLET FEVER

10.3.10.9.1. DEFINITION

10.3.10.9.2. SIGNS/SYMPTOMS

10.3.10.9.3. DIAGNOSIS/SCREENING

10.3.10.9.4. COMPLICATIONS

10.3.10.9.5. TREATMENT

10.3.10.10. VARICELLA

10.3.10.11. HAND-FOOT-MOUTH DISEASE

10.3.10.12. TORCH INFECTIONS

10.3.10.13. MUMPS

10.3.10.14. ROCKY MOUNTAIN SPOTTED FEVER

10.3.10.15. TOXIC SHOCK SYNDROME

10.3.10.16. COCCIDIODOMYCOSIS

10.3.10.17. HISTOPLASMOSIS

10.3.10.18. SCHISTOSOMIASIS

10.3.10.19. VISCERAL LARVA MIGRANS

10.3.10.20. ANIMAL BITES

10.3.10.21. NEONATAL SEPSIS

10.3.11. PEDIATRIC NEPHROLOGY

10.3.11.1. RENAL TUBULAR ACIDOSIS

10.3.11.2. WILMS TUMOR

10.3.11.3. RENAL DYSPLASIA

10.3.11.4. RENAL HYPOPLASIA

10.3.11.5. FANCONI SYNDROME

10.3.11.6. HORSESHOE KIDNEY

10.3.11.7. FEBRILE PROTEINURIA

10.3.11.8. RENAL VEIN THROMBOSIS IN INFANCY

10.3.11.9. CRYPTORCHIDISM

10.3.12. PEDIATRIC ORTHOPEDICS AND RHEUMATOLOGY

10.3.12.1. OSTEOGENESIS IMPERFECTA

10.3.12.2. DUCHENNE MUSCULAR DYSTOPHY

10.3.12.3. EHLERS-DANLOS SYNDROME

10.3.12.4. KAWASAKI'S DISEASE

10.3.12.5. TORUS FRACTURE

10.3.12.6. GROWTH PLATES

10.3.12.7. OSTEOMYELITIS

10.3.12.8. SEPTIC ARTHRITIS

10.3.12.9. TRANSIENT SYNOVITIS

10.3.12.10. OSGOOD-SCHLATTER DISEASE

10.3.12.11. LEGG-CALVE-PERTHES DISEASE

10.3.12.12. SLIPPED CAPITAL FEMORAL EPIPHYSIS

10.3.12.13. THE LIMPING CHILD

10.3.12.14. TODDLER'S FRACTURE

10.3.12.15. DEVELOPMENTAL DYSPLASIA OF THE HIP (DDH)

10.3.12.15.1. PREVIOUSLY KNOWN AS CONGENITAL HIP DYSPLASIA

10.3.12.15.2. DISORDER OF NEWBORNS WITH INSTABILITY IN THEIR HIP JOINTS, WHICH MAY PROGRESS TO A CHRONIC DISLOCATION IF IT IS NOT DIAGNOSED EARLY

10.3.12.15.3. ALTHOUGH THERE IS NO STRONG GENETIC RISK, THE “FOUR FS” ARE SEEN IN PATIENTS WITH DEVELOPMENTAL DYSPLASIA OF THE HIP:

10.3.12.15.4. DIAGNOSIS AND EXAM FINDINGS

10.3.12.15.5. OTHER CLINICAL FINDINGS AND WORKUP OF DDH

10.3.12.15.6. TREATMENT

10.3.12.16. OSTEOID OSTEOMA

10.3.12.17. SALTER-HARRIS FRACTURE CLASSIFICATION

10.3.12.18. GREENSTICK FRACTURE

10.3.12.20. PEDIATRIC OSTEOPETROSIS

10.3.12.21. JUVENILE IDIOPATHIC ARTHRITIS

10.3.12.21.1. JUVENILE IDIOPATHIC ARTHRITIS (JIA) IS THE MOST COMMON RHEUMATIC DISEASE IN CHILDREN THAT REFERS TO A GROUP OF DISORDERS THAT ALL SHARE THE CHARACTERISTIC OF ARTHRITIS

10.3.12.21.2. THE CRITERIA FOR CLASSIFICATION INCLUDE THE FOLLOWING:

10.3.12.21.3. JUVENILE IDIOPATHIC ARTHRITIS OCCURS IN ABOUT 22/100,00 CHILDREN AND AFFECTS GIRLS MORE THAN BOYS

10.3.12.21.4. THE MOST COMMON SUBTYPES IN DESCENDING ORDER ARE: OLIGOARTHRITIS, POLYARTHRITIS, AND SYSTEMIC-ONSET ARTHRITIS

10.3.12.21.5. THE ETIOLOGY OF JIA IS NOT COMPLETELY UNDERSTOOD BUT TWO COMPONENTS ARE CONSIDERED NECESSARY: IMMUNOLOGIC SUSCEPTIBILITY AND AN EXTERNAL TRIGGER

10.3.12.21.6. CLINICAL SYMPTOMS

10.3.12.21.7. A RARE BUT POTENTIALLY FATAL COMPLICATION IS MACROPHAGE-ACTIVATING SYNDROME THAT CAN PRESENT AT ANY TIME IN THE DISEASE COURSE

10.3.12.21.8. JIA IS A CLINICAL DIAGNOSIS OF EXCLUSION WITHOUT ANY DIAGNOSTIC LABORATORY TESTS

10.3.12.21.9. IMAGING

10.3.12.21.10. THE GOAL OF TREATMENT IS TO ACHIEVE REMISSION AND STOP JOINT DAMAGE

10.3.12.22. JUVENILE RHEUMATOID ARTHRITIS (JRA)

10.3.13. PEDIATRIC PULMONARY

10.3.13.1. CROUP

10.3.13.2. INHALED FOREIGN BODY

10.3.13.3. EPIGLOTTITIS

10.3.13.4. BACTERIAL TRACHEITIS (PSEUDOMEMBRANOUS CROUP)

10.3.13.5. PEDIATRIC PNEUMONIA

10.3.13.6. BRONCHIOLITIS

10.3.13.6.1. BRONCHIOLITIS IS INFLAMMATION OF THE BRONCHIOLES THAT RESULTS IN INFLAMMATORY BRONCHIOLAR OBSTRUCTION

10.3.13.6.2. BRONCHIOLITIS MOST COMMONLY OCCURS IN CHILDREN UNDER 2 YEARS OF AGE, WITH TWICE AS MANY GIRLS AFFECTED AS BOYS

10.3.13.6.3. RESPIRATORY SYNCYTIAL VIRUS (RSV) IS THE MOST COMMON CAUSE OF BRONCHIOLITIS, BUT OTHER COMMON RESPIRATORY VIRUSES MAY ALSO CAUSE BRONCHIOLITIS

10.3.13.6.4. SINCE BRONCHIOLITIS IS CAUSED BY INFECTION WITH VARIOUS RESPIRATORY VIRUSES, EPIDEMICS OCCUR DURING THE COLD AND FLU SEASON (NOVEMBER TO APRIL)

10.3.13.6.5. PATIENTS WITH CARDIAC DISEASE, LUNG DISEASE, OR IMMUNODEFICIENCIES, AND THOSE LESS THAN 3 MONTHS OF AGE, ARE AT RISK FOR SEVERE DISEASE REQUIRING HOSPITALIZATION FOR RESPIRATORY SUPPORT

10.3.13.6.6. PATIENTS TYPICALLY PRESENT WITH A GRADUAL ONSET OF UPPER RESPIRATORY SYMPTOMS SUCH AS:

10.3.13.6.7. PATHOPHYSIOLOGY

10.3.13.6.8. WHILE BRONCHIOLITIS IS A CLINICAL DIAGNOSIS, MANY HOSPITALS TEST ALL YOUNG CHILDREN WITH SYMPTOMS OF BRONCHIOLITIS FOR RESPIRATORY SYNCYTIAL VIRUS (RSV)

10.3.13.6.9. WORSENING AIRWAY OBSTRUCTION CAN LEAD TO HYPOXIA AND APNEA

10.3.13.6.10. TREATMENT IS PRIMARILY SUPPORTIVE AND INCLUDES SUCTIONING, BRONCHODILATORS, AND SUPPLEMENTAL OXYGEN

10.3.13.7. OTHER IMPORTANT PEDIATRIC PULMONOLOGY TOPICS

10.3.14. PEDIATRIC SYNDROMES

10.3.14.1. TRISOMY 18

10.3.14.2. TRISOMY 13

10.3.14.3. TURNER SYNDROME

10.3.14.4. INFANTILE SPINAL MUSCULAR ATROPHY

10.3.14.5. TRISOMY 21

10.3.14.6. VACTERL AND CHARGE

## 11. STEP 1

### 11.1. ORGAN SYSTEMS

11.1.1. IN UP TO ONE QUARTER OF CHILDREN DIAGNOSED, RICKETS MAY BE A PRESENTING SYMPTOM

11.1.2. CARDIOLOGY

11.1.2.1. LARGE VESSEL VASCULITIS

11.1.2.1.1. GIANT CELL (TEMPORAL) ARTERITIS

11.1.2.1.2. TAKAYASU ARTERITIS

11.1.2.2. PATHOLOGY

11.1.2.3. PHARMACOLOGY

11.1.2.3.1. ANTIHYPERTENSION DRUGS: ANGIOTENSIN AGENTS

11.1.3. ENDOCRINOLOGY

11.1.3.1. HYPOTHALAMIC-PITUITARY AXIS

11.1.3.1.1. ANTERIOR PITUITARY

11.1.3.2. ENDOCRINE PANCREAS

11.1.3.2.1. DIABETES MELLITUS

11.1.3.2.2. TYPE I DIABETES MELLITUS

11.1.3.2.3. TYPE II DIABETES MELLITUS

11.1.3.3. ENDOCRINE PHARMACOLOGY

11.1.3.3.1. DIABETES MELLITUS PHARMACOLOGY

11.1.3.4. OTHER PATHOLOGY

11.1.3.4.1. CARCINOID SYNDROME

11.1.4. GASTROENTEROLOGY

11.1.4.1. PATHOLOGY

11.1.4.1.1. CARCINOID

11.1.5. HEMATOLOGY/ONCOLOGY

11.1.5.1. HEMATOLOGICAL DISORDERS

11.1.5.1.1. OVERVIEW OF ANEMIA

11.1.5.1.2. THROMBOTIC MICROANGIOPATHIES

11.1.5.2. HEMATOLOGIC MALIGNANCIES

11.1.5.2.1. LYMPHOMA: NON-HODGKIN

11.1.5.3. HEMOSTASIS

11.1.5.3.1. THROMBOCYTOPENIA

11.1.5.3.2. ANTIPHOSPHOLIPID SYNDROME

11.1.6. ORTHOPEDICS & RHEUMATOLOGY

11.1.7. PULMONOLOGY

11.1.7.1. PATHOLOGY

11.1.7.1.1. NASOPHARYNGEAL DISORDERS

11.1.7.2. PHYSIOLOGY

11.1.7.2.1. OXYGEN-HEMOGLOBIN DISSOCIATION CURVE

11.1.8. REPRODUCTIVE

11.1.8.1. ANATOMY

11.1.8.1.1. PROSTATE

11.1.8.1.2. LIGAMENTS OF THE UTERUS

11.1.8.1.4. UTERINE TUBES

11.1.8.1.5. VAGINA

11.1.8.1.6. TESTES

11.1.8.1.7. EXTERNAL GENITALIA - FEMALE

11.1.8.1.8. UTERUS

11.1.8.1.9. EXTERNAL GENITALIA - MALE

11.1.8.1.10. OVARIES

11.1.8.1.11. CERVIX