USMLE Step 2 — Lesson 1 Pediatric Highlights for USMLE Step 2

Eduardo Pino, MD

NEWBORN-APGAR

Apgar Score 0 1 2

Appearance Blue, pale Body pink, ext blue All pink

Pulse (HR) 0 <100 >100

Grimace None Grimace Cough

Activity Limp Some flexion Active

Respiration Absent Slow irregular Good

NEWBORN-SKIN

• Subcutaneous fat necrosis

• Erythema toxicum

• Acne neonatorum

• Milia

• Hemangiomas

• Mongolian spots

• Nevus sebaceous

NEWBORN-HEAD

• Caput-scalp swelling, crosses suture lines, resolves in days

• Cephalhematoma - subperiosteal bleed, DOES NOT CROSS SUTURES, longer

resolution

• Fontanels-large, suspect hydrocephalus, hypothyroid

o Closure-anterior, 9-18 months

o Posterior, birth, 4-5 months

NEWBORN-EYES,NOSE

• Eyes

o Red reflex=lens clear

o White reflex=retinoblastoma

o Lens opacity=cataract

o Aniridia+hemihypertrophy=Wilms

• Nose

o Choanal atresia-blue baby pinks up on crying, catheter doesn’t pass nose

NEWBORN-ABDOMEN, GU

• Abdomen

o Masses-polycystic kidney most common

o Umbilical hernia-most close by 5 years

o Omphalocele-sac

o Gastroschisis-no sac

• GU

o Epispadias, hypospadias-don’t circumcise

o Undescended testes-bring down after 1 year

o Ambiguous genitalia-congenital adrenal hyperplasia (21 hydroxylase most

common)

NEWBORN-BIRTH INJURIES

• Fractures-clavicle most common-crepitus

• Forceps-facial nerve palsy, bruising

• Brachial plexus

o Erb-Duchenne:C5-C6, if C4, ipsilateral

diaphragmatic palsy

“waiter’s tip”

o Klumpke:C8-T1, “claw hand”

NEWBORN-SCREENING

• PKU-autosomal recessive

o mental retardation most common

o eczema, musty odor, FAIR HAIR, FAIR SKIN, BLUE EYES

• Galactosemia-autosomal recessive

o jaundice, hypoglycemia, cataracts

• Hypothyroid-T4 low, TSH high

o large fontanel, jaundice, mottled, constipation, large tongue, umb. hernia

NEWBORN-RESPIRATORY

• Common signs/symptoms- Cyanosis, tachypnea, nasal flaring, retractions, grunting

• Respiratory distress syndrome

o Surfactant deficiency, seen in preterm

o Ground glass appearance on X-ray

o Treat with surfactant, ventilator support

• Transient tachypnea of newborn

o Rapid descent, C/S

• Meconium aspiration syndrome

NEWBORN-JAUNDICE

• Physiologic

o Appears >24 hours of age

o peaks at 12.9 by 3 days

o resolves by 1 week

• Pathologic-first day, level >13, lasts > 1week

o Etiology-hemolysis-Rh, ABO

o biliary atresia-direct bilirubin,

o acholic stools

• Therapy-phototherapy only for indirect

NUTRITION

• Breast milk is best for infant

• Iron supplement after 6 months

• Contraindications-

o active, untreated TB

o syphilis

o AIDS

o herpes if breast lesions

o galactosemia

o varicella

• Formula-20 cal/oz

• Whole milk-only >1 yr. Bad for kidneys

GROWTH-HEIGHT

• Short stature

hypopituitarism

constitutional delay

familial short stature

deprivational dwarf

Turner

hypothyroidism

chronic disease

• Tall stature

normal-familial

obesity

endocrine-GH excess

o androgen excess

o hyperthyroidism

genetic

o Marfans

o Klinefelter

GROWTH-WEIGHT

Failure to Thrive

Malnutrition

Malabsorption

Allergies

Immune deficiency

Chronic disease

Obesity

<5% secondary to syndromes

Risk of obesity persisting to adults increases with advanced age of onset

DEVELOPMENT

• Newborn reflexes-most disappear by 4-6 mos, EXCEPT Babinski (18 mos),

parachute (never)

• Social smile 4-8 weeks

• Rolls onto back 4 mos

• Rolls onto stomach 5 mos

• Sits with support 6 mos

• Pincer grasp 9 mos

• 3 cubes at 15 mos, 4 at 18, 7 at 24

BEHAVIOR

• Attention deficit-inattentive, impulsive,distractible, hyperactive (4:1 males)

• Enuresis-primary nocturnal most common

• typically males, family history

• disorder of sleep/arousal

• treatment-time, alarms, imipramine DDAVP

• Encopresis-boys more common, usually psychological cause

USMLE Step 2 — Lesson 2 IMMUNIZATIONS

• NOT contraindications:

• Fever<105 after DPT

• Mild acute illness in otherwise well child

• Concurrent antimicrobial therapy

• Prematurity-immunize at chronological age

• Family history of seizures

• Family history of SIDS

IMMUNIZATIONS

• Don’t give live vaccines to immunocompromised

• Killed polio now recommended for initial series

• MMR-most effects 1-2 weeks later

• Delayed schedule-give as many as possible

• Missed immunizations-don’t start over

IMMUNIZATIONS-HIV

Vaccine No/ Moderate

Immunosupporess

Severe

Immunosupress

(Category 1,2) (Category 3)

DTP Yes Yes

OPV No No

IPV Yes Yes

MMR Yes No

Pneumococcal Yes Yes

Influenza Yes Yes

ID-SEPSIS/MENINGITIS

• Etiology- Age dependent

o Neonate-Group B Strep most common

E. coli

Listeria

o >2 months-pneumococcus most common

o College, military-meningococcus

• Clinical-bulging fontanel in infants

o Kernig, Brudzinski in older

• Know CSF findings

ID-SEPSIS/MENINGITIS

• Steroids useful in preventing H. flu sequelae

• Add vancomycin if Pneumococcus

• Rifampin prophylaxis for H. flu, Meningococcus

• Vaccines vs. H. flu, S. pneumoniae, N. meningitidis

ID-ENCEPHALITIS

• Etiology-viral

o Arbo, enteroviruses in seasonal epidemics

o HSV most common cause of sporadic

• Clinical-more abnormalities of mental function-confusion, delirium, combative, ataxia

ID-ENCEPHALITIS

• Diagnosis - PCR from CSF

• Temporal lobe involvement suspect HSV

• Treatment - acyclovir if HSV

ID-OSTEO/SEPTIC ARTHRITIS

• Osteomyelitis

o S. aureus most common

o Sickle cell - Staph, Salmonella

o Pasteurella after dog, cat bite

o Pseudomonas after sneaker puncture

o X-rays turn positive after 10-14 days

• Septic arthritis - Staph, also Strep

o Arthrocentesis test of choice

o Differential - cellulitis, JRA, synovitis, ALL

ID-PERTUSSIS

• Clinical

o conjunctivitis

o coughing spasms

o inspiratory whoop

o ·facial petechiae

• Lab-leukocytosis with lymphocytosis

o ·positive culture

o ·rapid fluorescent antibody stain

ID-PERTUSSIS

• History of incomplete immunizations

• Immunize to prevent, erythromycin to close contacts

• Erythromycin to patient shortens communicability

ID-RASH DISEASES

• Lyme disease-look for Long Island, Conn.

o Rash-erythema chronicum migrans

• Fifth’s disease-erythema infectiosum

o Rash-“slapped cheek”

o Parvovirus B19, can cause aplastic anemia

ID-RASH DISEASES

• Measles (rubeola)

o Cough, coryza, conjunctivitis, Koplik

o Rash accompanied by fever

• Roseola-rash after fever

• Rubella-3 day measles, lymphadenopathy

ID-RASH DISEASES

• Can immunize against measles, rubella, Lyme

• Rocky Mountain Spotted Fever

o Look for Carolinas

o Rash includes palms/soles

• Cat scratch-papule, granuloma, lymphadenitis

o PCR most sensitive for diagnosis

o Kittens transmit more than cats

ID-MISCELLANEOUS

• Mumps-orchitis rare before puberty

• HIV-most pediatric infections acquired at birth-zidovudine to mother decreases

transmission

• Mononucleosis - atypical lymphocytes

o Ampicillin rash

USMLE Step 2 — Lesson 3 POISONING

• Acetaminophen-check liver functions

o antidote: n-acetylcysteine

• Aspirin-ferric chloride test-qualitative

o metabolic acidosis with respiratory compensation in children

• Carbon monoxide-cherry red blood

o antidote-oxygen, hyperbaric

POISONINGS

• Tricyclic Antidepressants

• Leading cause of death

o seizures, arrhythmias

• Hydrocarbons - kerosene

o aspiration

• Organophosphates - DUMBELS

o antidote - atropine

POISONINGS

• Iron - signs of hemorrhagic gastroenteritis

o antidote - deferoxamine

• Lead - blood lead levels, lead lines

o antidote - EDTA, BAL

EYE

• Conjunctivitis-chemical most common <24h old

o Chlamydia most common infectious cause in newborn

• Strabismus-transient is normal up to 4 months old

EYE

• Amblyopia-“lazy eye”

o Hirschberg, Cover test

o patch good eye

• Cellulitis

o orbital-eyeball doesn’t move, proptosis preorbital-eyelids and surrounding

tissue

TEETH-PRIMARY ERUPTION

Lower(Mandibular) Upper(Maxillary)

Central Incisors 5-7 months 6-8 months

Lateral Incisors 7-10 months 8-11 months

Cuspids(canines) 16-20 months 16-20 months

First Molars 10-16 months 10-16 months

Second Molars 20-30 months 20-30 months

TEETH-SECONDARY

Lower Upper

Central Incisors 6-7 years 7-8 years

Cuspids 9-11 years 11-12 years

1st Premolars 10-12 years 10-11 years

2nd Premolars 11-13 years 10-21 years

1st Molars 6-7 years 6-7 years

2nd Molars 12-13 years 12-13 years

3rd Molars 17-22 years 17-22 years

EARS, NOSE, THROAT

• Otitis media

o Etiology - S. pneumo most common

H. flu nontypable

B. catarrhalis

o Meningitis most common intracranial complication

• Otitis externa-from repeated wetting

Etiology - Pseudomonas, S. aureus

Clinical-pain exacerbated by moving ear canal

EARS, NOSE, THROAT

• Sinusitis - S. pneumo, H.flu, Staph.

Symptoms-purulent nasal discharge headache, sinus tenderness

• Epistaxis - nose picking most common

• Pharyngitis - viral/bacterial (Group A strep)

o Throat culture is gold standard

o Complications - rheumatic fever

EARS, NOSE, THROAT

• Peritonsillar abscess-tonsil bulges, uvula deviates to non-involved side

“HOT POTATO VOICE”

• Retropharyngeal abscess-Strep, look at lateral X-ray of neck

• Cervical lymphadenitis-usually infectious

o Viral/bacterial pharyngitis, TB, cat scratch, rarely tumors

RESPIRATORY

• Foreign bodies-peanut most commonly aspirated

o Look for sudden onset respiratory distress, wheezing, may be witnessed

event

o Diagnosis-bronchoscopy, CXR hyper-inflated

• Croup-parainfluenza virus

o Clinical-barking cough, inspiratory stridor

o P/A neck film-STEEPLE SIGN

o Steroids beneficial

RESPIRATORY

• Epiglottitis H. flu type b

o Age- 3-10 years

o Clinical-dysphagia, drooling, muffled voice

o CHERRY RED EPIGLOTTIS

o THUMBPRINT SIGN on lateral neck

o Tx-secure airway, antibiotics

RESPIRATORY

• Asthma-Reversible airways disease

o wheezing is hallmark, no clubbing

o Differential-congenital malformations

foreign bodies

cystic fibrosis

bronchiolitis

o Tx-bronchodilators, steroids

o Prevent-cromolyn, leukotriene antagonist

RESPIRATORY

• Bronchiolitis-RSV, children<2 years

o Clinical-wheezing, rales, tachypnea

o Prevention-monoclonal antibodies

• Cystic fibrosis-autosomal recessive

o chromosome 7, long arm

o chronic obstruction-clubbing seen

o SWEAT TEST

RESPIRATORY

• SIDS-most common cause of death 1-12 mo

• Peak at 2-3 mo, winter, midnight-9 AM

• Sleep position

USMLE Step 2 — Lesson 4 CARDIOVASCULAR

• Innocent murmur-never diastolic

o never >2/6

o 3-7 years of age

o best at left lower, midsternal border

o musical, vibratory

o no significance

CARDIOVASCULAR CLASSIFICATION

STENOTIC R to L L to R MIXING

Aortic stenosis TOF PDA Truncus

Pulmonic stenosis Transposition VSD TAPVR

Coarctation Tricuspid atresia ASD Hypertrophic LH

CARDIOVASCULAR

• ASD-systolic ejection murmur

o WIDE FIXED SPLIT OF S2

• PDA-machinery murmur, to and fro

o wide pulse pressure, bounding pulses

o Tx-surgical closure indomethacin

• VSD-most common heart defect

o loud harsh pansystolic murmur

o 30-50% of small defects close by 1 year

CARDIOVASCULAR

• Endocardial cushion defect-Common AV canal

o Common in Down’s syndrome

o CHF early-feeding difficulty, sweat while feeding, tachypnea

• Coarctation of the aorta-common in Turner’s

o Weak/delayed/absent lower extremity pulses, Rib notching on CXR

CARDIOVASCULAR

• Tetralogy of Fallot- Most common cyanotic

o pulmonary stenosis

o VSD

o overriding aorta

o RV hypertrophy

o CXR-boot shaped heart, pulmonary markings o PE-cyanosis, single 2nd heart sound

o Complications-cerebral thrombosis, ischemia, brain abscess

CARDIOVASCULAR

• Transposition-most common with cyanosis in 1st 24 hrs.

o Keep ductus open with prostaglandin

o CXR-egg on a string

• Pulmonary atresia- cyanosis at 2-3 days

• Tricuspid atresia- single S2 pansystolic murmur

• Total anomalous pulmonary venous return

o CXR-snowman or figure 8

CARDIOVASCULAR

• Rheumatic fever- rheumatic fever-associated with Strep throat

J=joints

O=carditis (O looks like a heart)

N=nodules (subcutaneous)

E=erythema marginatum

S=Sydenham’s chorea

o minor criteria-fever, arthralgia, previous RF ESR, CRP, prolonged P-R interval + prior Strep infection

o complications-valve disease-mitral, aortic

CARDIOVASCULAR

• Hypertension

o Essential-no known underlying cause

o More common in adolescents

o Secondary-more common in infants and children

o Look for renal disease-UTI, obstructive lesion of urinary tract, prior umbilical

catheter as newborn

GASTROINTESTINAL

Diarrhea

• Viral-rotavirus most common

o adenovirus, Norwalk virus

• Bacterial-E.coli think of HUS

o Salmonella -tx prolongs carrier

o Shigella-tx with trimethop/sulfa

o Campylobacter-erythromycin

o C. difficile-think of prior antibiotic

o parasites-Giardia, cryptosporidium

GASTROINTESTINAL VOMITING

Constipation

• Voluntary withholding most common (functional constipation) outside of infancy

o also-imperforate anus

cystic fibrosis-meconium ileus

anteriorly displaced anus

Hirschsprung-aganglionosis

Dx by BIOPSY

GASTROINTESTINAL VOMITING

• Age related causes

o neonate-obstruction

o infants-gastroenteritis, reflux, allergy, over-feeding, inborn errors of

metabolism

o child/adolescent-gastroenteritis, toxic ingestion, appendicitis, pancreatitis

• Duodenal atresia-bilious vomiting common in Down’s, DOUBLE BUBBLE

GASTROINTESTINAL VOMITING

• Reflux - chronic, cough, vomiting, apnea

o pH probe is gold standard

• Pyloric stenosis - NONBILIOUS, PROJECTILE VOMITING

o more common in males, firstborn

o lab-hypochloremic, hypokalemic metabolic alkalosis

o Ultrasound test of choice

GASTROINTESTINAL BLEEDING

• Upper-esophagitis, ulcers, gastritis, epistaxis

• Lower-neonate-swallowed blood-Apt test

o necrotizing enterocolitis-premature, low Apgar, pneumatosis intestinalis

o other-milk allergy, gastroenteritis, ANAL FISSURE (infants)

GASTROINTESTINAL

• Inflammatory bowel disease-ulcerative colitis and Crohn’s

o Dx by biopsy

o both cause bloody stools, fever, abdominal pain

o Crohn’s-fissures, fistula, abscess

GASTROINTESTINAL

• Intussusception-typically 6-18 months

o Clinical-crampy abdominal pain CURRANT JELLY STOOL

o PE-sausage shaped abdominal mass

o ·Dx-barium enema-coil spring sign

GASTROINTESTINAL

• Meckel’s diverticulum-disease of 2’s

o 2% of population, 2:1 males, 2 years of age, 2 types of tissue, 2 feet from

ileocecal valve

o painless rectal bleed, can cause intussusception

o Dx-technetium scan

RENAL

• Acute Glomerulonephritis

o triad of hematuria,edema, hypertension

o follows Group A Strep infection

o C3 decreased

o Complications-renal failure, hypertension

• Alport’s

• X-linked dominant

• Clinical-microscopic hematuria, proteinuria,

HEARING LOSS, CATARACTS

RENAL

• Nephrotic syndrome-proteinuria,edema, hypoproteinemia, hyperlipidemia

o usually follows viral respiratory infection

o C3 normal

o Complications-INFECTION-peritonitis

• Urinary tract infection

o males more common <1 year, then females

o E. coli most common

o Urine culture is gold standard

USMLE Step 2 — Lesson 5 ORTHOPEDICS

• Intoeing

o Metatarsus adductus-can be brought to neutral

o Talipes equinovarus-heel also deviated

o Tibial torsion

o Femoral anteversion

ORTHOPEDICS

• Limping

o Congenital hip dysplasia-0-3 years, u/s

o Legg-Perthes-4-8 years-avascular necrosis of femoral head

o Slipped capital femoral epiphysis->11 years obese adolescent, think deficient

gonads

ORTHOPEDICS

• Popliteal cyst (Baker)-painless, nonpulsatile

• Osgood Schlatter-tenderness, swelling of tibial tubercle

o common in physically active pubertal children

• Radial head subluxation (nursemaid)

o sudden traction to arm

ORTHOPEDICS

• tumors-occur in adolescence, rapid bone growth

o Osteosarcoma-most common, risk if bilateral retinoblastoma o bone sclerosis on X-ray

o Ewing’s-“onion skin” on X-ray

ALLERGY/IMMUNOLOGY

• Allergic rhinitis-IgE mediated

o Clinical-sneezing, rhinorrhea, allergic salute, allergic shiners, nasal crease

o Tx-antihistamines, leukotriene antagonists

• Hereditary angioedema-C1 esterase inhibitor def.

• Bruton’s-all major immunoglobulins involved

o symptoms at 6-12 mos.-recurrent infections, esp. pneumococcus

o Tx-replace IgG

ALLERGY/IMMUNOLOGY

• DiGeorge-T cell deficiency

o TRUNCUS ARTERIOSUS, fishmouth, micrognathia

o NEONATAL HYPOCALCEMIA is 1st manifestation

• Wiskott-Aldrich: X-linked recessive

o MR TEXT-low IgM, Recurrent infections, T(and B) cell deficiency, Eczema,

Thrombocytopenia

RHEUMATOLOGY

• Juvenile Rheumatoid Arthritis

Types-

o polyarticular-many, small joints RF-, RF+

o pauciarticular-few, large joints

o type I-ANA+, girls, iridocyclitis

o type II-HLA B27+, boys, ankylosing spondylitis

o systemic-fever, rash, then joints

o Differential-rheumatic fever, SLE, Lyme, ankylosing spondylitis,

osteomyelitis, ALL

RHEUMATOLOGY

• Systemic lupus erythematosus-autoimmune

o BUTTERFLY (malar) rash

o renal involvement in children

o neonatal lupus-congenital heart block

• Mucocutaneous lymph node syndrome (Kawasaki)

o FEVER+ 4 of 5 of following: conjunctivitis, mucous membrane changes,

peripheral extremity changes, rash, cervical lymph nodes

o CARDIAC INVOLVEMENT

RHEUMATOLOGY

• Henoch-Schoenlein purpura

o Rash usually below waist

o Usually follows viral illness

o Can have renal, GI involvement

HEMATOLOGY

ANEMIA

• Iron Deficiency most common

o cause-low birth weight, diet (9-24 mos) blood loss (ulcer, Meckel, whole

cow’s milk in infants)

o clinical-pallor, irritability, murmur

o labs- ferritin, serum iron, binding capacity, FEP, Hgb o differential-lead, thalassemia, chronic disease

o tx-iron-see reticulocytosis in 72h, Hgb 3-4 wks

HEMATOLOGY

ANEMIA

• Hemolytic

o Hereditary spherocytosis-autosomal dominant

presents as anemia, jaundice

labs-OSMOTIC FRAGILITY TEST

tx-splenectomy

o Enzyme defects-pyruvate kinase, G6PD

HEMATOLOGY

ANEMIA

• Sickle cell anemia - develops after 2 months

o dactylitis 1st manifestation, splenic, bone infarcts, infections (Salmonella,

Pneumococcus)

• Dx-electrophoresis

HEMATOLOGY

• Idiopathic thrombocytopenia-autoimmune

o Usually follows viral infection

o Petechiae, but patient appears well

o Bone marrow-normal

o Tx-gamma globulin, steroids

• Hemophilia

o Factor VIII (classic, A)-X linked recessive

HEMARTHROSIS

Replace factor

ONCOLOGY

• Acute lymphocytic leukemia-most common childhood cancer

o clinical-acute onset, anorexia, pallor, fever, bone pain in 1/4

o dx-bone marrow

o tx-chemotherapy, radiation, transplant

o RELAPSE TO TESTES, CNS

• Wilms -nephroblastoma

o abdominal mass

o distorts renal outline

ONCOLOGY

• Neuroblastoma-many times abdominal,

o presents anywhere there is neural crest

o Increased catecholamines in urine

• CNS-most common solid tumors

o infratentorial (posterior fossa ) most common

cerebellar astrocytoma most common

clinical-morning headache, vomiting

o supratentorial-craniopharyngioma cause of short stature

USMLE Step 2 — Lesson 6 NEUROLOGY

• Seizures

o Febrile-most common

rapid rise of temperature

generalized, tonic-clonic, 10-15 mins

normal EEG

tx-treat fever

o Infantile spasms-West syndrome

EEG-hypsarrhythmia

tx-ACTH, prednisone

o Petit mal-3/sec spike/wave, ethosuximide

NEUROLOGY

• Progressive mental retardation

o Lesch-Nyhan-self-mutilation

gouty arthritis

o Wilson’s-disorder of copper metabolism

initial signs are liver related

Kayser-Fleischer rings

o Mucopolysaccharidoses-Hunter-X linked recessive, all others autosomal

recessive

o Tay-Sachs-lose developmental milestones, cherry red macula

NEUROLOGY

• Werdnig-Hoffman-spinal muscular atrophy

o Severe hypotonia-floppy baby

o Fasciculations, FROG LEG POSTURE

o EMG-fibrillations

o muscle bx-denervation

o nerve bx-slowed conduction

o Autosomal recessive

• Guillain-Barré-follows viral illness

o Ascending weakness, paralysis, lose deep tendon reflexes

tx-supportive, plasmapheresis, IVIG

NEUROLOGY

• Duchenne muscular dystrophy-X linked rec

o most common inherited neuromuscular disease

o Hip girdle weakness, Gower’s sign

o dx-greatly elevated creatine kinase, muscle bx

• Neurofibromatosis-von Recklinghausen

o Café-au-lait spots, axillary/inguinal freckling

o Lisch nodules, neurofibromas, acoustic neuroma

o autosomal dominant, risk for malignancy

NEUROLOGY

• Tuberous sclerosis-autosomal dominant

o Ash leaf spot, sebaceous adenomas, shagreen patch, periventricular

calcified tubers on CT

o seizures very common

• Sturge-Weber-facial nevus-port wine stain

o seizures difficult to control

o intracranial calcifications

o mental retardation

ABUSE

• Clinical-unexplained injury

o physical and injury don’t correlate

o lash marks, loop marks

o bite >3 cm=adult

o RETINAL HEMORRHAGE=shaken

o old healing fractures, bruises

o venereal disease in prepubertal child

• Tx-treat any injury, infection

o document, REPORT

ADOLESCENT

• Know Tanner stages

• Breast buds 1st sign of puberty in females

• Testicular enlargement 1st sign in males

• Mortality-Accidents, especially motor vehicle

o Suicide-males more successful

o Homicide

o Cancer-leukemia, Hodgkin’s, bone

• Normal-breast asymmetry, gynecomastia, irregular menses

• Acne-hormones, dirt, bacteria

Pediatric Highlights for USMLE Step 2

Eduardo Pino, MD

End