Usmle Exam Slides

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USMLE EXAM SLIDES!!!Tarek Hassouna

47,XYY Paternal cause @ meiosis II -gamete receiving both copies of one homolog (in this case YY)

Prophase => crossover

4 chromosomes 2 types

2 chromosomes 2 types All x 2

1 chromosomes 1 types All x 4

Can not flex elbow! Biceps brachialis Biceps brachi

Brachial Plexus

Cannot ABduct! arm

Deltoids

Cannot extend wrist

Claw hand lesioned by tauma to heel of hand -fracture of hook of hammate

Nerve innervations of arm

Dr CuMa Radial nerve injury = wrist drop Ulnar nerve injury = claw hand Median nerve injury = Ape hand

The hands

Guyons Canal associated with ulner nerve injury!! - claw hand!!!

Anterior compartment

Leg compartmentsDeep posterior compartment

Unhappy triadMedial collateral ligament

Anterior cruciate ligament

Lateral Meniscus

A blow from the lateral side of the knee causes a tearing of the medial coll lig. occurs among foot players This occurs because of attachment of the lateral meniscus which tears Medial meniscus is associated with the ACL so that also tears Thus, you get the unhappy triad

Postnatal derivatesfetal Umbilical vein Umbilical arteries remanant Ligamentum teres hepatis - falciform ligament Medial umbilical ligament

Ductus arteriosusDuctus venosus Foramen ovale allantois notochord

Ligamentum arteriosumLigamentum venosum Fossa ovalis Urachus median umbilical ligament Nucleus pulpos of invertebral disc

Celiac trunk

Left gastric

Spleenic

Right gastric Hepatic proper Gastroduodenal

Common hepatic

Right gastroepiploic

Left gastroepiploic

Hesselbach Triangleindirect hernia -internal deep ring -into the scrotum compresses sperm chord -infants

Direct hernia -hasselbech triangle -medial to epigastric artery -external ring!!!

Rectus abdominis muscle (medially) Inferior epigastric vessels (superior and laterally). Inguinal ligament, sometimes referred to as Poupart's ligament (inferiorly)

Contralateral -face + arm paralysis + sensory loss -aphasia (dominant) -left sided neglect

Medial surface of brain -leg+ foot area -sensory cortices

Most common site of CoW aneurysm!! -visual field defects

Contralateral -homonymous hemianiopia with macular sparing -visual changes Locked in syndrome - CNIII is intact

Most common site of aneurysm!! -CNIII palsy

Ipsilateral -faical paralysis -cochlear paralysis -Vestibular -facial pain + temp -dystaxia Contralateral loss of pain + temp Ipsilateral -dysphagia -hoarsness -decreased gag reflex -facial pain + temp -trigeminal nucleus -ataxia

Bilateral hemiparisis Contralateral proprioception deficit Ipsilateral paralysis of hypoglossyl

MoA: Block the presynaptic reuptake of 5HT + NE + DA -increased levels!!!

Treatment /DOC: Neuropathic pain

Adverse effects!!Anticholinergic effects!! Orthostatic HypoTN Dry mouth + confusion + sedation Cardiac tox!!

Nortrptyiline Desipramine Imipramine Clomipramine Amitriptyline Things to know!! Impramine eneuresis Nortryptiline least orthostatic!! Clomipramine most serotonergic TCA!!

MoA: Reuptake inhibitor only for seratonin!!!

Treatment /DOC: DOC!! depression Premature ejeculation Bulemia OCD Panic disorder Fluoxetine Citalopram Sertraline Escitalopram Paroxetine Fluvoxamine

Adverse effects!!Nausea Headache Diahrrhea Restlessness + insomnia Seratonin syndrome

Things to know!! DOC!! Seratonin syndrome = 2 SSRI + 1 MAO

Fluoxamine OCD!

MoA: Block the enzyme monoamine oxidase

Treatment /DOC:

Tranylcypromine Phenelzine Adverse effects!!Must have tyramine free diet!! HTN crisis!! -tx with phentolamine + nitropurriside

Things to know!! tyramine free diet!!

Calculating + interpreting RiskRisk Odds ratio Equation (a/b)/(c/d) = ad/bc Interpretation Odds of having disease in exposed group vs. unexposed getting the disease exposed vs. unexposed Difference Exposed vs. unexposed

Relative Risk Attributable risk

a/(a+b) / c/(c+d) (a/a+b)/(c/c+d)

Diagnostic testingDisease (+) Disease (-)

Test (+)

TP

FP

Test (-)

FN

TN

Sen => TP/(TP+FN) Spec => TN/(TN+FN)SNOUT => Sensitivity rules OUT! SPIN => specificity rules IN!

Sleep stages awake

description Awake + alert Active + mental concentration - Beta waves

EEG readings

Awake but eyes closed Alpha waves 1 Light sleep

2

Deeper sleep- bruxism

3-4

Deepest non REM sleeep Sleepwalking Night terror Bed wetting

REM

Dreaming loss of motor tone erections

TachycardiaMore than 100 BPM

Atrial fibrillation

What to know: -uncoordinated -irregularly irregular -upper chambers quiver bag of worms appearance

Atrial flutter

What to know -coordinated electrical stimulation regularly irregular - due to a loop of electricity in the upper chambers of the heart.

Supraventricular tachycardia

What to know: -repeated periods of very fast heartbeats begin and end suddenly -Same as paroxysmal SVT

Wolf-Parkinson White

What do you need to know: - extra (accessory) connection - most common causes of fast heart rate disorders (tachyarrhymthmias) in infants and children

Perfusion vs. Diffusion vs. Airway problemsproblemRestrictive Perfusion defect

PaO2Decrease -causes pul HTN!!

PaCO2decrease

pHincrease

RRincreases

Clincal presentationSOB!! Pul HTN Narrow S2 Loud S2 RV hypertrophy S4 sound increases on inspiration

Fungus Protozoates Cancer Neuromuscular diseases

Inpiratory crackles + alveolar infilitrates hyaline diseaseObstructive airway Bacterial!! Decreased Increases decrease -CO2 retainer!!! pneumotactic center stimulated!! increases Tachypnea SOB!!

V/q mismatchV/Q high PaO2 Increased thus perfect environment of tuberculosis Decreased no ventilation to that area!! PaCO2 Decreased since ventilated, Co2 can escape! Increased no ventilation to that area!!

low

Antiarrythmics in kids

Ventilatory and ABG patterns in ComaBreathing PatternHyperventilationHypocapnia => vasoconstriction => decreased CSF formation

Metabolic PatternComp Metabolic acidosis Respiratory alkalosis

pH, PaCO2, HCO3pH < 7.3 PaCO2 < 40 HCO3 < 17 pH > 7.45 PaCO2 < 40 HCO3 > 17 pH < 7.3 PaCO2 < 90 HCO3 > 17 pH > 7.45 PaCO2 > 45 HCO3 > 30

Specific ConditionsUremia, DKA, lactic acidosis, acute sepsis, salicylates, methanol, ethylene glycol Hepatic failure, acute salicylate intoxication, pychogenic causes, sudden onset dyspnea Respiratory failure from CNS or PNS disease, chest conditions or deformities Alkali ingestion. Usually no impairment of consciousness; suspect psychogenic Low volume state!

HyperventilationHypocapnia => vasoconstriction => decreased CSF formation

Hypoventilation

Respiratory acidosis Uncomp Metabolic alkalosis

Hypoventilation

Toxic SyndromesGroup BP P R T MSDelerium

Pupil size

Peristalsis

Diaphoresis

OtherDry mucous membranes, flush, urinary retention Salivation, lacrimation, urination, diarrhea, bronchorrhea

Anticholinergic agents Cholinergic agents

-/

-/

-

Normal to depressed

Ethanol or sedativehypnoticsOpioids Sympathomimetic agents Withdrawl from ethanol or sedatives Withdrawl from opioids

-

-/ -

Depressed

-/

Hyporeflexia

Depressed Agitated

Hyporeflexia Tremor, seizure

Agitated, confused Normal, anxious

Tremor, seizure

Vomiting, rhinorrhea, piloerection, diarrhea

Goldfranks Toxicologic Emergencies, 2006

Glycogen storage diseasesGlycogen Storage disease Von Griekes Type I Enzyme deficiency Glucose 6 phosphatase CP Hypoglycaemia Hepatomegaly Hyperlipidemia Failure to grow Hepatomegaly Muscle weakness Tendionous Xanthomas!! Hypoglycaemia Hepatomegaly Hyperlipidemia Causes myopathy Keywords Lactic acidocis Hyperurecemia Protuberant belly Xanothomas on buttocks Death by age 2 Heart failure Glycogen debrancher!!! Accumuation of dextrin like structures in cytosol -no fatty infiltration

Pompes type II

Acid maltase

Coris / Forbes type III

Glycogen debrancher

***Anderson Type IV

Glycogen brancher

Hepatospleenomegaly Cirrohosis Failure to thriveExcersise induced cramps rhabdomyelosis

Cirrohsis!!!

McArdles type V

Muscle glycogen phosphorylase

Renal failure -dark urine!!! -myoglobinuria

Hers Type VI Taruis Type VII

Liver glycogen phosphorylase Muscle PFK

Hypoglycaemia Hepatospleenomegaly Excersize induced cramps Weakness Growth retardation Haemolytic anemia

HypernatremiaHypernatremia

Vascuar

Renal

Endocrine

GIT

Hypovolemia Main cause!! if water is down then Na+ concentration rises

Glycouria Diabetes insipdus Decreased vasopression Conns syndrome

Cushings disease

Severe watery diahrrea

HyponatremiaHyponatremia

Renal

GIT

Respiratory

Endocrine

CNS

Cardiac

Nausea SIADH increased ADH Severe diahrrea Vomitting Small cell carcinoma Increased cortisol Addisons Vomitting Headache Malaise Lidocaine toxicty prolonged QT interval Na+ channel blocker

Concentrated urine Cerebral edema

increased H2O retained oliguria

Hypercalcemia

Hypercalcemia

GIT

CNS

Cardiac