Uworld: 5-18

Front 1

Female infant
Hand swelling
Posterior neck mass
Neck mass consists of cystic spaces separated by connective tissue with lymphoid aggregates

Diagnosis
Explain findings

Back 1

Neck mass = CYSTIC HYGROMA
These are tumors of the neck that are apparent at birth. Often seen in infants with TURNER'S SYNDROME.

Swelling of hands and feet (lymphedema) is another manifestation of TURNER syndrome.

Both occur to abnlts of lymphatic outflow in Turner's.

Front 2

Cardiac defect associated with Turner's.

Back 2

Aortic COARCTATION

Front 3

Fracture surgical neck of humerus

Back 3

Axillary

Front 4

Fracture head of radius

Back 4

Radial (this is where humerus articulates with radius)

Front 5

Nerve innervating the corachobrachialis

Back 5

MCN

Front 6

Cushing Disease vs Cushing Syndrome:
General
Diagnosis

Back 6

Cushing Syndrome: Glucocorticoid excess due to exogenous sources, ACTH secreting pituitary adenoma, ectopic produciton of ACTH or CRH, adrenocortical hyperplasia

Cushing Disease: Cushing syndrome that results from ACTH-secreting pituitary adenoma

Diagnostics:
-Low dose Dexamethasone will not suppress either (this is how you know there's a Cushingoid etiology)
-High dose dexamethasone will suppress the pituitary adenoma (Cushing Dz)--this will be seen as a decrease in cortisol

-If high dose dexamethasone does not result in dec'd ACTH, then there must be an ectopic source of ACTH

Front 7

Acute stress disorder vs Post-traumatic stress disorder:
General

Back 7

Both have identical syx (recurrent nightmares and flashbacks, potential memory loss, and exaggerated startle response)

Acute stress disorder lasts no more than 4 weeks, while post-traumatic stress disorder lasts longer than four weeks

Front 8

12 year-old male
Decreased exercise intolerance
Urine discoloration after strenuous activity
Muscle pain with physical activity

Diagnosis
Pathophys

Back 8

McArdle's Syndrome (type 5 glycogen storage dz)

Due to deficiency of myophophorylase (isoenzyme of glycogen phosphorylase) , which leads to failure of muscle glycogen-->glucose-1-phosphate

Front 9

This enzyme removes supercoils.

Back 9

Topoisomerase

Front 10

This enzyme unwinds DNA double helix.

Back 10

Helicase

Front 11

This enzyme stabilizes unwound template strands.

Back 11

Single-strand binding proteins (only binds to ssDNA)

Front 12

This enzyme synthesizes RNA primer.

Back 12

Primase (RNA polymerase)

Front 13

This enzyme synthesizes the leading DNA strand.

Back 13

DNA Pol III

Front 14

This enzyme synthesizes the lagging DNA strand.

Back 14

DNA Pol III

Front 15

This enzyme removes RNA primer and replaces the RNA with DNA.

Back 15

DNA Pol I

Front 16

This enzyme proofreads DNA 3' to 5'.

Back 16

ALL DNA POLYMERASES

Front 17

This enzyme joins Okazaki fragments.

Back 17

DNA Ligase

Front 18

This enzyme proofreads DNA 5' to 3'.

Back 18

DNA Pol I (this is for RNA primer removal)

Front 19

How does an endonuclease differ from an exonuclease?

Back 19

Endonucleases cut DNA at very specific DNA sequences

Exonucleases remove nucleotides from the end of a DNA molecule

Front 20

beta-blocker overdose:
Treatment
Treatment MOA

Back 20

Glucagon; activates G-protein-coupled receptors on cardiac myocytes, causing activation of adenylate cyclase-->raising intracellular cAMP.

Results in calcium release from intracellular stores-->inc'd sinoatrial firing.

i.e., inc'd heart rate and contractility.

Front 21

CD marker specific for macrophages.

Back 21

CD14

Front 22

Mycobacteria that grow in parallel chains ("serpentine cords"):

Explain

Back 22

Means mcobacteria possess CORD FACTOR (a mycoside); correlates with virulence as it allows inactivation of nphils, damages mitochondria, and induces release of TNF.

Front 23

Which oral nitrate has the highest bioavailability?

Back 23

Isosorbide mononitrate (close to 100%)

Unlike isosorbide DInitrate and nitroglycerin which undergo considerable first-pass metabolism in the liver when taken orally

Front 24

Fetal anomalies associated with impaired swallowing (other than anencephaly).

Back 24

GI obstruction secondary to duodenal, esophageal, or intestinal atresia

Front 25

What are the signs of lithium toxicity?
What drugs can exacerbate this? Describe the mechanism by which they do so.

Back 25

Lithium toxicity: neuromuscular excitability, coarse tremors; fascicular twitching, ataxia, delirium

Lithium is similar to salt in the way it passes through the nephrons.

Drugs that increase lithium reabsorption by the kidneys are:
Thiazides (not loops!)--impair Na reasborption in DCT, but kidney eventually increases Na resorption in PCT (and absorbs more lithium as a result)

ACE inhibitors: unknown mechanism
and NSAIds: Unknown mechanism
Probably due to renal injury

Moral of the story: hemodialysis is the best way to reduce blood lithium

Front 26

Diphenoxylate:
MOA
Use

Back 26

Opiate anti-diarrheal that binds to mu opiate receptors in GI tract and slows motility

Low doses: anti-diarrheal effects w/o euphoria

high doses: euphoria, physical dependence (often combined with atropine to discourage abuse)

Front 27

This drug can be used in secretory diarrhea.

Back 27

Octreotide

Front 28

What is passive-aggression?

Back 28

Behavior that expresses hostile feelings in a non-confrontational manner

Front 29

Identify defense mechanism:
Soldier describes war atrocities in frank, non-emotional terms.

Back 29

Isolation

Front 30

Friedreich ataxia:
Pathophys
Presentation

Back 30

Degeneration of ascending and descending spinocerebellar tract-->gait ataxia

Degeneration of dorsal columns and DRG-->loss of position and vibration sensation

Kyphoscoliosis and pes cavus (foot abnormalities)

HYPERTROPHIC CM

DM in about 10%

Front 31

MHC I vs MHC II:
Structure
Location
Function
Type of Antigen
Effects of Antigen Presentation

Back 31

MHC I;
Made of heavy chain and beta-2 microglobulin
Found in all nucleated cells
Presnts antigen to CD8 cells
Antigens = viruses, tumor proteins (processed in cytoplasm)
Leads to apoptosis of presenting cell

MHC II:
Structure consists of alpha and beta polypeptide chains
Found in APCs (B cells, macs, DCs, Langerhans Cells)
PResent g to CD4
Ag is bacterial; ag's are phag'd and digested by lysosomes within which Ag binds MHC II
Activation results in stimulation of humoral/cell-mediated immune response

Front 32

The proximal 1/3 of the ureter receives its blood from ______.

Back 32

The renal artery

Front 33

What structures comprise the retroperitoneum?

Back 33

Vessels: Abdominal aorta, IVC

Organs: Pancreas, kidneys, adrenals; 2-some of 4th duodenum, asc/desc colon, rectum, ureters, bladder

Support: Vertebral column, pelvic muscles

Front 34

Which structures comprise the intraperitoneum?

Back 34

Transverse colon
Liver
Spleen

(leads to hemoperitoneal bleeding--bleeding in peritoneal space)

Front 35

What is pulsus paradoxus and when does it occur?

Back 35

Decrease in systolic BP of greater than 10mmHg with inspiration

Occurs in setting of:
Cardiac tamponade
Constrictive pericarditis
Severe obstructive lung gz
Restrictive cardiomyopathy

Note: Pulsus paradoxus occurs because inspiration causes increase in systemic venous return, resulting in inc'd right heart volumes. Under normal conds, this results in expansion of RV into pericardial space with little impact on left side of heart. But in conditions that impair expansion into the pericardial space, the inc'd RV volume pushes the interventricular septum toward the left. Results in dec'd diastolic volume and stroke volume, resulting in dec'd sys BP during inspiration.

Front 36

What is the effect of cAMP accumulation in smooth muscle cells?

Back 36

Relaxation

Front 37

What is the effect of opening calcium channels in smooth muscle cells?

Back 37

Constriction

Front 38

What changes occur during right heart failure that make the body prone to developing edema?

How is it counteracted?

Back 38

RHF-->increased central venous pressure
Interstitial fluid pressure rises due to inc'd plasma filtration

As interstitial fluid pressure increases, so does lymphatic drainage

Inc'd lymphatic drainage compensates for moderate central venous pressure elevations to prevent interstitial edema.

With large central venous pressure elevations, net filtration increases in excess of lymphatic reabsorptive capacity and overt edema develops.

Front 39

Holosytolic murmurs are associated with _______.

Back 39

Mitral Regurgitation
Tricupsid Regurgitation
Ventricular Septal Defects

Front 40

Additive vs Synergistic Effects

Back 40

Additive: combined effects of two drugs = sum of the effects from individual drugs

Synergistic: combined effect exceeds sum of individual drug effects

Front 41

What is a permissive effect?

Back 41

One drug augments the effects of another (to allow it to reach the drug's full potential)

Ex: Cortisol doesn't has vascular reactivity on its own, but when combined with NE, it increases NE's vascular reactivity.

Front 42

What drugs comprise first generation anti-histamines?

What drug class should be avoided while on these drugs?

Back 42

Diphenhydramine
Chlorpheniramine
Promethazine
Hydroxyzine

Do not take these with benzodiazepines! Will cause excessive sedation!

Front 43

List the steps of the IP3 second messenger system.

What hormones employ this?

Back 43

alpha-1, oxytocin, vasopressin vascular receptor, AgII, GHRH, TRH, GnRH

Effects:
GDP swaps for GTP on alpha subunit of G protein
alpha subunit allows Phospholipase C to bind, which degrades phospholipids to:
IP3 and DAG
DAG stimulates Protein Kinase C
Ca2+ MAJORLY activates Protein Kinase C
Protein Kinase C then phosphorylates proteins which exert physiologic effects

Front 44

Fenfluramine:
Drug Class
AE

Back 44

Appetite suppressant

Increased incidence of pulmonary HTN (Dyspnea on exertion) and can progress to cor pulmonale w/RVH (leads to sudden cardiac death)

Front 45

32 year-old male
Difficulty walking
Tingling in feet
Decreased strength of lower extremities
Absent deep tendon reflexes
Diarrhea two weeks ago

Diagnosis
Pathophys

Back 45

Guillain-Barre Syndrome--demyelinating syndrome of peripheral nerves characterized by ascending muscle weakness and paralysis

10-30% attributable to Campylobacter jejuni infection

Front 46

This antipsychotic is metabolized to phenobarbital.

Back 46

Primidone

Front 47

This diuretic can cause pulmonary edema.

How?

Back 47

Mannitol; an osmotic diuretic.

Works by increasing plasma or tubular fluid osmolality. Inc'd osmolality causes extraction of water from interstitial space (cells) into vascular space, with subsequent diuresis.

In brain, water redistribution from tissues into plasma helps reduce edema and ICP. However, this rapid rise in vasculature volume can also worsen pulmonary edema, especially those with CHF.

Front 48

Beginning in the right atrium and ending in the aorta, list the minimum/maximum pressures a catheter would detect.

Back 48

RA: 0-->8
RV: 4-->25
PA: 9-->25
LA: 2-->12
LV: 9-->130
Aorta: 70-->130

Front 49

Patchy areas of skin anesthesia
Hypopigmentation on upper extremities
Bacteria invading Schwann cells

Diagnosis

Back 49

Myobacterium leprae

Front 50

Chlamydia:
Characteristics relevant to antiobiotics

Back 50

Dosen't have a peptidoglycan wall; produces PCN binding proteins but doesn't make peptidoglycans (weird)

Need to use antiribosomal antibiotics, like macrolides and tetracyclines.

Front 51

Lipofuscin:
Pathological significance
What does it look like?

Back 51

Yellow/brown granules which represent lipid polymers and phospholipids. Arise due to FREE RADICAL INJURY and LIPID PEROXIDATION.

It's a wear and tear sign of aging.

Front 52

This drug is structurally similar to pyridoxine.

Back 52

INH

Front 53

Streptomycin:
Specific MOA

Back 53

Streptomycin binds the 30S ribosomal subunit and distorts its structure, impairing the initiation of protein synthesis and inhibiting intitiation complex.

Front 54

How do eukaryotic and prokaryotic ribosomes differ?

Back 54

Eukaryotic: 60S, 40S
Prokaryotic: 50S, 30S

Front 55

Abdominal colic
Constipation
Headache
Iron deficiency anemia

Diagnosis

Back 55

Lead poisoning

Could also see neuropathy like wrist drop.

Front 56

In what industries should be concerned about lead poisoning?

Back 56

Anything involving batteries, alloys, ammunition--mining, smelting, chemical processing, recycling, spray paint, radiator repair.

Front 57

Describe and diagnose

Back 57

BASOPHILIC STIPPLING
lead poisoning

Front 58

What enzyme is inhibited by lead poisoning?

Back 58

ALA dehydratase (and ferrochelase?)

Front 59

What are the three MEN disorders and how do they differ?

Back 59

MEN1:
Parathyroid (hyperCa2+)
Pancreatic (gastrin--PEPTIC ULCERS, DIARRHEA)
Pituitary Adenoma (prolactin, ACTH)

MEN 2a:
Medullary carcinoma (Thyroid--Calcitonin)
Pheo
Parathyroid (hyperCa2+)

MEN 2B:
Medullary carcinoma of thyroid (calcitonin)
Pheo
Marfanoid habitus

Front 60

Von Hippel-Lindau:
PResentation

Back 60

Hemangioblastoma
Pheochromocytoma
Renal Cell Carcinoma

Front 61

WBC Casts:
Significance

Back 61

If there's fever and systemic syx (chills, nause, vomiting, flank/abdominal pain, CVA tenderness): acute pyelonephritis

Front 62

Raloxifene:
Drug Class
Effects on women with osteoporosis and history of breast cancer

Back 62

Raloxifene is a SERM

Acts as estrogen agonist on bone, CV system, and blood lipoproteins (slows bone resorption)

In breast and uterus, acts as estrogen antagonist, thus reducing risk of ER-positive breast cancer

Front 63

How can Crohn's result in a fistula?

Back 63

Transmural inflammation:
Chronic inflammation causes edema and fibrosis-->narrows intestinal lumen (strictures)

Inflammation and necrosis cause ulcer formation-->can penetrate entire thickness of affected intestinal wall, leading to formation of fistula.

Remember that in ulcerative colitis, only the mucosa and submucosa are inflamed so strictures and fistulas are uncommon.

Front 64

G6PD Deficiency:
Mode of inheritance

Back 64

X-linked Recessive

Front 65

Hereditary Spherocytosis:
Mode of inheritance

Back 65

X-linked Recessive

Front 66

Mutation found in emergence of small adenomtaous polyp from normal colonic mucosa.

Back 66

APC mutation (SPORADIC)

Front 67

Mutation found in emergence of adenocarcinoma from colonic mucosa.

Back 67

p53 (final step into adenocarcinoma)

Front 68

5 year-old male
Lethargy, oliguria
History of bloody diarrhea
Elevated BUN/Cr
Fragmented erythrocytes

Diagnosis
Cause

Back 68

Hemolytic uremic syndrome secondary to E Coli 0157:H7 (EHEC)

Front 69

Raw oysters (not Hep A)

Back 69

Vibrio cholera

Front 70

35 year-old female
Acute MI
Mitral valve thickening with masses on both sides
Normal coronary arteries

Diagnosis
Cause

Back 70

Libman-Sachs Endocarditis

Secondary to SLE and immune-complex deposition

Front 71

t(15;17):
Molecular and Clinical Effects

Back 71

AML

Forms PML/RAR, which codes for abnormal retinoic acid receptor

Inhibits myeloblast differentiation producing promyelocytic leukemia:
anemia, thrombocytopenia, neutropenia result from marrow replaced by leukemic cells

Front 72

What are the effects of low serum C1 esterase?

What medication class is contraindicated and why?

Back 72

Low Serum C1 esterase = Hereditary angioedema (painless, non-pitting edema of face, neck, lips, tongue->RESPIRATORY OBSTRUCTION)

With low C1 esterase there are elevated levels of active C1 and bradykinin (both are activators of angioedema)

If gave ACE-inhibitor, would increase bradykinin levels even more. Could precipitate angioedema even more.

Front 73

10 year-old male
Restlessness, jerking movements of extremities
Vaccines up to date
Sore throat three months ago

Diagnosis
Pathophys

Back 73

Group A Strep infection leading to Anti-Neuronal Antibodies against caudate/subthalamic nuclei

This is called Sydenham Chorea and is a manifestation of acute rheumatic fever

Risk of mitral/aortic valve disease

Front 74

21 year-old athlete
Weight loss, fatigue despite increased food intake
Polyuria, polydipsia

Diagnosis
What test would confirm this?

Back 74

DM 1

Confirm with fasting blood sugar >126 on 2 separate occasions

Front 75

62 year-old female
Expectorates pale fluid
Biopsy of lung mass shows columnar cells that line alveolar septa without evidence of invasion
Cells are well-differentiated, columnar

Diagnosis

Back 75

Despite lack of invasion, this is still a malignant neoplasm. It's bronchioalveolar carcinoma.

Will demonstrate a pneumonia-like consolidation.