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USMLE Step 1 > High Yields Week 1 > Flashcards

High Yields Week 1 Flashcards

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1
Q

Describe the absorption of glucose in the kidney in states of NORMAL serum glucose and HIGH serum glucose

A

Normal serum glucose = completely reabsorbed

High serum glucose = some glucose excreted in urine

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2
Q

The complete or partial loss of an X chromosome in Turner syndrome results from what genetic abnormality?

A

Paternal meiotic nondisjunction

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3
Q

What is the most common cause of sporadic encephalitis?

A

HSV-1

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4
Q

Chromaffin cells of the adrenal medulla and parafollicular C cells of the thyroid arise from what embryonic tissue and layer?

A

Neural crest tissue from the Ectoderm

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5
Q

Prostatectomy (accidental nerve severing) or injury to the prostatic plexus can cause what consequence?

A

Erectile Dysfunction

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6
Q

What is the most common non-nuclear DNA found in eukaryotic cells?

A

Mitochondrial DNA (mtDNA)

  • small circular DNA resembling a bacterial chromosome
  • maternal mtDNA is passed down from the mother to all of her offspring
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7
Q

What are the 3 most important predisposing factors for hypoglycemia in patients with Type 1 Diabetes Mellitus?

A
  • Excessive insulin dose
  • Inadequate food intake
  • Exercise/physical activity (muscle contractions also cause glucose uptake by muscle cells via GLUT4)
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8
Q

What is Conversion Disorder?

A

Conversion disorder is characterized by neurological symptoms (voluntary motor and sensory deficits) that cannot be explained by another medical or mental disorder.

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9
Q

Neural tube defects occur during the 4th week of fetal development and can be detected by what diagnostic markers?

A

↑ a-fetoprotein (AFP) in maternal serum
↑ acetylcholinesterase (AChE) in amniotic fluid

These appear due to leakage of fetal CSF through the neural tube defect.

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10
Q

Clinical presentation and seromarker associations for ankylosing spondylitis

A 
Young men
Morning stiffness, low back pain
Tender sacroiliac joints
NO rheumatoid factor
Associated with HLA-B27 (MHC Class I)
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11
Q

List the conduction speed of the following cardiac tissue from fastest to slowest: Ventricular muscle, Atrial muscle, AV node, Purkinje fibers

A

Purkinje fibers (fastest)
Atrial muscle
Ventricular muscle
AV node

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12
Q

Cleft lip results from failure of what intrauterine process?

A

Cleft results when the MAXILLARY prominence fails to fuse with the intermaxillary segment during the 5th-6th week of embryonic development.

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13
Q

Prevention of reinfection with a similar strain of influenza virus can be attributed to antibodies against what influenza viral antigen?

A

Hemagglutinin (promotes viral entry)

A humoral response with antibodies directed against hemagglutinin is generally the most important source of protection (this goes for the vaccine as well).

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14
Q

Universal Start Codon

A

AUG

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15
Q

Stop Codons

A

UGA
UAG
UAA

(U Go Away, U Are Gone, U Are Away)

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16
Q

What does right dominant coronary circulation mean?

A

It means the right coronary artery gives rise to the posterior descending artery (inferior wall of heart)

85-90% of people have right dominant coronary circulation

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17
Q

Clinical features and pathophysiology of hypercalcemia

A

Muscle weakness, constipation, mental status changes, increased thirst and urination

Hypercalcemia causes impaired depolarization of neuromuscular membranes (neuro/muscular symptoms) and impaired concentration of urine in the distal tubule (urination/thirst)

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18
Q

Dry beriberi vs. Wet beriberi

A

Dry beriberi - symmetrical peripheral neuropathy (sensory and motor impairments)

Wet berberi - high-output congestive heart failure (dilated cardiomyopathy, peripheral edema, etc.)

Beriberi (dry and wet) is caused by thiamine (B1) deficiency.

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19
Q

What is the embryologic origin of melanocytes?

A

Neural crest cells

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20
Q

Patient presents with fever, fatigue, anorexia, tachycardia, tachypnea, hypotension and a new holosystolic murmur. Disease/Dx?

A

Acute rheumatic fever resulting from an untreated Group A Strep infection.

  • Early lesion is mitral valve regurgitation
  • Aschoff body may be seen on cardiac biopsy
  • (Latel lesion is mitral stenosis)
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21
Q

What fungus produces thin, septate hyphae with acute angle V-shaped branches?

A

Aspergillus fumigatus

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22
Q

Maple syrup urine disease results from the defective breakdown of branched chain amino acids because of a defective branched chain a-ketoacid dehydrogenase complex. What five cofactors are required for proper function of this enzyme complex?

A 
Thiamine
Lipoate
Coenzyme A
FAD
NAD
(Tender Loving Care For Nancy)
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23
Q

5 year old child presents with palpable purpura, abdominal pain, arthralgias and hematuria a week following upper respiratory infection. Disease/Dx?

A

Henoch-Schonlein purpura (IgA immune-complex mediated vasculitis)

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24
Q

What two factors play an important role in osteoclast differentiation?

A

Macrophage colony-stimulating factor (M-CSF) and activated nuclear factor kappa-B ligand (RANK-L)

Both M-CSF and RANK-L are produced by osteoblasts and bone marrow stromal cells

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25
Q

Define Pleiotropy

A

Pleiotropy describes instances in which multiple phenotypic manifestations (‘symptoms’) result from a single genetic mutation

  • most genetic illnesses exhibit pleiotropy
  • TLDR - pleiotropy is where a single gene mutation fucks a lot of shit up
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26
Q

What type of immune response do inactivated (killed) vaccines invoke (B cell/T cell)? Live-attenuated vaccines?

A

Inactive (killed) vaccines - B cell (humoral) response ONLY

Live-attenuated vaccines - T cell (cellular) AND B cell response

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27
Q

What causes infertility in cystic fibrosis?

A

Infertility is due to absent vas deferens bilaterally (azoospermia)

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28
Q

In metabolic acidosis, urinary pH decreases due to increased excretion of what substances?

A

H+, NH4+, H2PO4-

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29
Q

What embryologic dysfunction causes a patent foramen ovale?

A

Incomplete fusion of atrial septum primum and secundum

A patent foramen ovale can result in a very rare cryptogenic stroke in which an embolus of venous origin can travel through the heart defect into systemic circulation up into the brain.

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30
Q

What do RNA polymerase I, II and III produce?

A

RNA polymerase I - ribosomal RNA (rRNA -> in the nucleolus)
RNA polymerase II - messenger RNA (mRNA)
RNA polymerase III - transfer RNA (tRNA)

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31
Q

Where are T3 and reverse T3 (rT3) derived from?

A

T3 (active form) - small amount release from thyroid gland but the majority of T3 arises from T4 conversion to T3 in peripheral tissues.

reverse T3 (inactive form) - generated almost entirely from peripheral conversion of T4

T4 is the major secretory product of the thyroid gland

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32
Q

What enzyme deficiency can cause severe combined immunodeficiency (SCID)?

A

Adenosine deaminase deficiency

Adenosine accumulation is toxic to lymphocytes leading to widespread death of T and B lymphocytes

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33
Q

What is the most common site of injury in a traumatic aortic rupture (car accident)?

A

Aortic Isthmus (located right as the aorta begins its descent to the abdomen, 2 o’clock position)

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34
Q

What physiologic function compensates for moderate central venous pressure increases, (due to mildly decreased cardiac function) thereby preventing peripheral edema?

A

Increased tissue lymphatic drainage

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35
Q

What effect does deacetylation of histones have on gene expression?

A

Deacetylating histones INHIBITS gene expression.
-causes chromatin to tightly shut, disabling transcription

(acetylating histones would increase gene expression)

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36
Q

5 y/o girl presents with neurologic abnormalities, partial albinism and immunodefiency. Peripheral blood smear shows giant cytoplasmic granules in neutrophils and monocytes. Disease/Dx?

A

Chediak-Higashi syndrome

Autosomal recessive disorder causing defect in neutrophil phagosome lysosome fusion

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37
Q

What serum biomarker reflects osteoblastic activity?

A

Bone-specific alkaline phosphatase

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38
Q

Patient presents with pneumonia, low platelet count, fatigue, myalgias and retroorbital headaches. History reveals frequent exposure to animal waste product. What is the causative organism?

A

Coxiella burnetti (causes Q fever)

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39
Q

What is a paradoxical embolism?

A

Occurs when a thrombus from the VENOUS system crosses into arterial circulation via an abnormal connection between the right and left cardiac chambers (patent foramen ovale, atrial septal defect, ventricular septal defect)

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40
Q

What is kinesin?

A

Kinesin is a microtubule-associated, ATP-powered motor protein that facilitates the anterograde transport of neurotransmitter-containing secretory vesicles down axons to synaptic terminals.

TLDR - carries vesicles down axons for release at synaptic terminals

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41
Q

What are the pressures (mmHg) of the airways, alveoli and intrapleural space at the FRC (functional residual capacity)?

A

Airways - 0 mmHg
Alveoli - 0 mmHg
Intrapleural space - always negative (~-5 mmHg)

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42
Q

What is the most common mutation causing cystic fibrosis and its pathogenesis?

A

3-base pair deletion at Phe508

Causes abnormal posttranslational processing causing abnormal folding of CFTR protein. Abnormal CFTR is targeted for proteasomal degradation, preventing it from reaching cell membrane.

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43
Q

What are the two physiologic etiologies of polyhydramnios?

A

Decreased fetal swallowing (gastrointestinal obstruction or anencephaly)

Increased fetal urination (↑ cardiac output due to anemia or TTTS)

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44
Q

What is the name of the sound on cardiac auscultation that immediately precedes the first heart sound?

A

S4 heart sound (hypertrophic cardiomyopathy)

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45
Q

What treatment should be considered in severe asthmatics that are not responsive to short/long-acting beta agonists or oral corticosteroids?

A

Anti-IgE antibodies (Omalizumab)

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46
Q

What type of cell junctions exist at the blood-brain barrier?

A

Tight junctions

The BBB is formed by tight junctions between nonfenestrated capillary endothelial cells that prevent the paracellular passage of fluid and solutes
-lipid soluble diffusion or carrier-mediated transport only

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47
Q

Where in the nephron of the kidney is the majority of water reabsorbed?

A

Proximal tubule ( > 60% of H20)

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48
Q

What is the most common cause of viral meningitis?

A

Enteroviruses (coxsackie, echovirus, polio, etc)

  • normal glucose (CSF)
  • marginally elevated proteins (CSF)
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49
Q

What type of collagen is present in scar tissue?

A

Type I Collagen

  • Can be seen following fibrosis of an infarcted organ (for example)
  • Most prevalent collagen in the human body
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50
Q

What are the diagnostic markers for diabetes mellitus?

A

fasting glucose > 126 mg/dL
random glucose > 200 mg/dL
hemoglobin A1c > 6.5%

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51
Q

Given phenotypically normal parents, what is the probability that a female sibling of a male affected by an X-linked recessive disease will give birth to an affected child?

A

1/8

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52
Q

What is factitious disorder?

A

A psychological disorder in which the patient consciously creates physical and/or psychological symptoms in order to assume ‘sick role’ and get medical attention.

TLDR - they hurt themselves for attention

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53
Q

What cells contribute to the pathogenesis of centriacinar emphysema (associated with smoking)?

A

Alveolar macrophages and infiltrating neutrophils

-these inflammatory cells release proteases

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54
Q

The superantigenic property of toxic shock syndrome toxin (from Staph aureus) results in activation of what immunologic cells?

A

CD4+ T cells and macrophages

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55
Q

Mature erythrocytes cannot synthesize heme because they lack what cellular organelle?

A

Mitochondria

Mitochondria are necessary for the first and final 3 steps of heme synthesis

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56
Q

What complications can arise from atrial fibrillation in a patient with severe aortic stenosis?

A

Atrial fibrillation leads to decreased atrial contraction -> decreased LV filling -> decreased preload -> decreased CO (on top of ↓ CO from aortic stenosis) -> backup of blood into pulmonary veins -> pulmonary edema

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57
Q

Define sensitivity

A

Sensitivity is the probability of a POSITIVE test result in a person who actually has the disease

It is important to have high sensitivity in screening tests

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58
Q

t(15;17)

A

Acute Promyelocytic Leukemia (APML)

  • involves translocation of retinoic acid receptor
  • inhibits differentiation of myeloblasts into mature granulocytes
  • symptoms - anemia, thrombocytopenia, neutropenia, DIC
  • treatment - All-trans retinoic acid
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59
Q

What precursor amino acid is required for the synthesis of Nitric Oxide?

A

Arginine

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60
Q

Th2 helper cells stimulate B cell antibody production. What lymphokines released by Th2 cells promote B cell class-switching to IgE?

A

IL-4 and IL-13 promote IgE production

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61
Q

An immunosuppressed patient with meningitis has a lumbar puncture. CSF fluid shows gram-positive rods with tumbling motility. What is the causative organism?

A

Listeria monocytogenes

-typically from food poisoning (unpasteurized milk)

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62
Q

Is rabies virus vaccine live attenuated or inactive (killed)?

A

Rabies virus vaccine is INACTIVE (killed)

-B cell humoral response only

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63
Q

Mutation of the ApoE4 gene is responsible for what disease?

A

LATE-onset familial Alzheimer disease

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64
Q

What enzyme deficiency is present in chronic granulomatous disease?

A

NADPH oxidase deficiency

(Deficiency of this enzyme leads to an inability of neutrophils to form the oxidative burst necessary to kill organisms in phagolysosomes)

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65
Q

Rubbing a person’s neck in an attempt to slow down their heart rate is stimulating what structure and nerve?

A

This action is stimulating baroreceptors in the carotid sinus

Parasympathetic impulses from this carotid sinus reflex travel to the medullary centers via the glossopharyngeal nerve

This carotid sinus reflex eventually results in a signal carried to the heart via the vagus nerve resulting in decreased CO and SVR (BP)

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66
Q

What embryonic structure does the thymus arise from?

A

3rd pharyngeal (branchial) pouch

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67
Q

What embryonic structure does the parathyroid gland arise from?

A

3rd and 4th pharyngeal (branchial) pouches

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68
Q

Patient presents with double vision (diplopia) that is worse when walking down stairs or reading. Does not affect vision when walking up stairs. Disease/Dx?

A

Trochlear nerve (CN IV) palsy

  • innervates the superior oblique m., which causes the eye to internally rotate and depress (looks in and down)
  • hence the patient has trouble walking down stairs while looking down
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69
Q

What cephalosporins should be used to treat Pseudomonas aeruginosa?

A

Ceftazidime (3rd gen) or Cefepime(4th gen)

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70
Q

Vitamin B12 deficiency is associated with which two elevated serum markers?

A

Elevated homocysteine AND methylmalonic acid

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71
Q

Patient presents with nocturnal palpitations, head pounding with exertion, involuntary head bobbing and widened pulse pressures. Disease/Dx?

A

Aortic regurgitation

widened pulse pressure/head bobbing is particularly helpful

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72
Q

What does a Northern blot detect?

A

mRNA

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73
Q

What does a Southern blot detect?

A

DNA sequences

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74
Q

What does a Western blot detect?

A

Protein

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75
Q

What does a Southwestern blot detect?

A

DNA-binding proteins

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76
Q

What are the crescent formations seen in RPGN actually composed?

A

Notably - Fibrin deposits

Crescents consist of glomerular parietal cells, monocytes, macrophages, as well as abundant fibrin

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77
Q

What ion flows into the cells during Phase 0 in cardiac pacemaker cells? cardiomyocytes?

A

Cardiac Pacemaker Cells - Calcium (Ca2+) influx (slow)

Cardiomyocytes - Sodium (Na+) influx (fast)

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78
Q

In a normal (bell-shaped/Gaussian) distribution, what percentage of observations lie within 1 SD? 2 SD? 3 SD?

A

68/95/99 rule

1 Standard Dev - 68%
2 Standard Dev - 95%
3 Standard Dev - 99%

Note, 68% encompasses a total from both sides of the mean

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79
Q

What gene mutation is associated with achondroplasia (dwarfism) and what is its inheritance pattern?

A

Gain-of-function mutation in FGFR3

Autosomal Dominant

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80
Q

What region of lymph nodes do T lymphocytes reside?

A

Paracortex

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81
Q

What region of the lymph nodes do B lymphocytes reside?

A

(cortical) Follicles

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82
Q

What artery supplies the distal 1/3 of the transverse colon, descending colon, sigmoid colon and rectum?

A

Inferior Mesenteric Artery

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83
Q

What is adenomyosis?

A

The presence of endometrial glandular tissue within the myometrium

(heavy menstrual bleeding and uniformly enlarged uterus are common clinical findings)

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84
Q

Which two major arterial beds are the most susceptible to atherosclerosis?

A

Coronary arteries and lower abdominal aorta

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85
Q

Down syndrome is associated with increased risk of what leukemias?

A

Acute lymphoblastic leukemia (10-20x ↑ risk)

Acute myelogenous leukemia

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86
Q

What is the wobble hypothesis (relating to protein translation)?

A

The first 2 nucleotide positions on the mRNA codon require traditional base pairing, but the third “wobble” nucleotide position may undergo less stringent base pairing
(this fits into concept of ‘degenerate’ genetic code in that multiple codes exist for 1 amino acid)

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87
Q

What is a Krukenberg tumor?

A

A gastric tumor that has metastasized to the ovary

  • presents with unintentional wt loss, epigastric pain and adnexal masses
  • will appear as mucin-secreting signet cells
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88
Q

Graft-versus-host-disease can occur after transplantation of what organs?

A

Allogeneic bone marrow transplantation
-donor bone marrow makes leukocytes that target host tissue

Organs rich in lymphocytes (liver)
-immunocompetent donor T cells from the graft survive and migrate into host tissues

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89
Q

Valproate is an anti-seizure drug that is teratogenic. What type of birth defects occur from valproate?

A

Neural tube defects (such as meningocele)

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90
Q

Patient biopsy reveals thickened bronchial walls, lymphocytic infiltration, mucous gland enlargement and patchy squamous metaplasia of the bronchial mucosa. What disease process did this patient die from?

A

Chronic bronchitis - likely due to lifelong cigarette smoking

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91
Q

Do the majority of Down syndrome cases arise from nondisjunction during maternal meiosis I or meiosis II?

A

Meiosis I

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92
Q

What is nondisjunction?

A

The failure of chromosome pairs to separate properly during cell division

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93
Q

What regions of the body does HPV infect?

A

Anus, vagina, cervix, true vocal cords (infants)

HPV ‘prefers’ stratified squamous epithelium

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94
Q

What is another name for B cell class switching?

A

Isotype switching

IgM, IgG, etc. are different heavy chain isotypes

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95
Q

When is myocardial perfusion the greatest?

A

Diastole

During diastole, the intraventricular pressure is lower than the aortic pressure, allowing for coronary perfusion

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96
Q

Why is the Haemophilus influenzae vaccine conjugated with tetanus toxoid (similar to S. pneumoniae vaccine)?

A

To elicit a T cell-dependent immune response

(B cell response from H flu vaccine is not effective in small children who have not developed a mature humoral immune system)

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97
Q

Patient presents with recent onset fatigue and dyspnea. Pt has hypotension, tachycardia and distended jugular veins. Heart sounds are muffled on auscultation and pulse becomes undetectable during inspiration. Disease/Dx?

A

Cardiac Tamponade

Beck’s Triad (acute tamponade)

  • hypotension
  • distended neck veins (JVD)
  • muffled heart sounds
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98
Q

What is the inheritance pattern of neurofibromatosis type 1 (NF1)?

A

Autosomal dominant

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99
Q

What vitamin supplement is given during (and before) pregnancy to prevent neural tube defects?

A

Folic acid supplementation

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100
Q

Where are serotonin-releasing neurons of the CNS located?

A

Raphe nuclei

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101
Q

Which transmembrane glucose transport protein is responsive to insulin and what type of cells are these glucose transporters predominantly found in?

A

GLUT-4 is responsive to insulin

GLUT-4 transport proteins are found in skeletal muscle cells and adipocytes

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102
Q

After what period of time does myocardial ischemia cause permanent damage to cardiomyocytes?

A

30 minutes

After 30 minutes of ischemia, ischemic injury to cardiomyocytes becomes irreversible and they forever lose function

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103
Q

Proteases (such as elastase) in alveolar fluid are derived from what cells?

A

Alveolar macrophages and infiltrating neutrophils

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104
Q

In statistics, what is power?

A

Power (1 - Beta) is the probability of rejecting a null hypothesis when it is truly false
(a study’s ability to detect a difference when one actually exists)

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105
Q

What are the two most important opsonins in the human body?

A

IgG and complement C3b

(Opsonins bind to the surface of foreign cells and act as a handle for receptors on phagocytes to grasp, enhancing phagocytosis)

106
Q

What is the difference between a true and false diverticulum

A

True diverticulum - intestinal outpouching containing all 3 layers; mucosa, submucosa, muscular layer
(Meckel’s diverticulum is a true diverticulum)

False diverticulum - contains only 2 layers; mucosa and submucosa
(Zenker’s diverticulum is a false diverticulum)

107
Q

Patient presents with 6 months of persistent watery diarrhea with no accompanying abdominal pain, fever or vomiting. Her gastric contents show a total lack of gastric acid. Her symptoms are relieved by somatostatin treatment. Disease/Dx?

A

VIPoma

VIP hypersecretion by VIPoma stimulates sodium, chloride, and water secretion into the bowel

108
Q

What are ‘confounders’ which cause confounding bias?

A

Confounders are extraneous factors that correlate with both the exposure and the disease

109
Q

What cardiac abnormalities are associated with Turner syndrome (45,XO)?

A

Bicuspid aortic valve (most common)

Coarctation of aorta (preductal)

110
Q

How are the fingers/digits of the hand numbered?

A

Thumb - 1st digit

Pinky finger - 5th digit

111
Q

What is negative selection in T cell maturation process?

A

Negative selection is a process of T cell maturation in the thymus by which apoptosis is induced in develop T cells that bind to self MHC/antigens with overly high affinity
(this prevents autoimmune reactions)

112
Q

What intra-abdominal organ is most commonly injured during blunt trauma?

A

Spleen (intraperitoneal organ)

113
Q

What antibiotics are first line treatments for Clostridium difficile infection?

A

Metronidazole and vancomycin

114
Q

Primary biliary cirrhosis causing biliary obstruction can result in malabsorption of what vitamins?

A

Fat soluble vitamins - A, D, E, K

115
Q

Pt presents with night blindness and thickened, dry skin (hyperkeratosis). What deficiency is present?

A

Vitamin A deficiency

116
Q

What is rheumatoid factor?

A

Rheumatoid factor is an IgM antibody specific for the Fc component of self IgG

(in RA, it is thought that RF binding of IgG creates immune complexes that eventually deposit in synovium and cartilage resulting in the chronic inflammation seen in rheumatoid arthritis)

117
Q

Multiple ring-enhanced lesions are seen on MRI of an HIV patient. What is the likely cause of these brain lesions?

A

Toxoplasmosis

118
Q

Pt presents with symmetrical muscles weakness in his hips and shoulders for 6 weeks with difficulty rising from chairs and climbing stairs. Muscle biopsy shows CD8+ lymphocyte infiltration and serum shows elevated creatine kinase. Disease/Dx?

A

Polymyositis

progressive symmetrical muscle weakness

119
Q

What is the most common cause of unilateral fetal hydronephrosis?

A

Obstruction at the ureteropelvic junction

caused by inadequate canalization of the ureteropelvic junction, the connection site between the kidney and the ureter

120
Q

Who does medicare cover?

A

Elderly (> 65 yrs) and Disabled

MedicarE is for Elderly

121
Q

Who does medicaid cover?

A

Homeless, undocumented immigrants, pregnant women, low-income families

MedicaiD is for Destitute

122
Q

What cell surface markers do immature T-lymphocytes express?

A

Both CD4 and CD8

123
Q

Staph saprohyticus frequently causes what infection? Is it catalase +/-? coagulase +/-? Novobiocin sensitive/resistant?

A

S. saprophyticus causes UTI in young women
Catalase +
Coagulase -
Novobiocin resistant

124
Q

Which hypothalamic nucleus regulated the circadian rhythm (sleep cycle)?

A

Suprachiasmatic nucleus

125
Q

What type of immune cell is likely to be found in bronchoalveolar lavage fluid of a patient with sarcoidosis?

A

CD4+ lymphocytes

126
Q

What would be the p-value of a study that shows a 95% confidence interval that does not cross the null value?

A

p-value

127
Q

Pt presents with blistering on the back of hands and forearms that has progressively gotten worse over the years. Disease/Dx?

A

Porphyria cutanea tarda

  • the most common disorder of porphyrin synthesis
  • results from a uroporphyrinogen decarboxylase deficiency
  • causes itchiness and photosensitivity on sun-exposed areas
128
Q

What is the function of haptoglobin?

A

Haptoglobin binds circulating hemoglobin and reduces renal excretion of free hemoglobin, preventing tubular injury

Low haptoglobin levels are seen in hemolysing diseases (like sickle cell) because it is being used to bind all the free hemoglobin

129
Q

What are the most common cancers in women in order of incidence?

A
  1. Breast cancer
  2. Lung cancer
  3. Colon cancer
130
Q

What cancer causes the high mortality in women?

A

Lung cancer

131
Q

Visceral obesity, measured as increased waist circumference is an important predictor of what metabolic disorder?

A

Type 2 diabetes mellitus / insulin resistance

132
Q

A 12 yo girl shows up with a history of arguing with teachers, refusing to follow rules, fighting with siblings, disobeying her parents and resisting homework and chores. Disease/Dx?

A

Oppositional defiant disorder

differentiate from conduct disorder which involves aggression and cruelty towards people/animals

133
Q

Glutathione reductase deficiency causes a similar clinical picture and pathophysiology to what other disease/deficiency?

A

Glucose 6-phosphate dehydrogenase deficiency (G6PD)

Both result in a deficiency of reduced glutathione which increases the susceptibility of RBCs to oxidative damage

134
Q

Where in the lymph node do B cells proliferate and class switch?

A

Germinal centers

135
Q

What is commonly used to stimulate surfactant production in premature infants with surfactant deficiency?

A

Corticosteroids (dexamethasone)

corticosteroids increase surfactant production by accelerating maturation of type II pneumocytes

136
Q

What is the most commonly injured muscle in rotator cuff syndrome (injured rotator cuff) and what movement will particularly cause pain?

A

Supraspinatus muscle

Injury to the supraspinatus muscle will cause pain on abduction of the arm

137
Q

What immune cells release IFN-y

A

T lymphocytes produce and release IFN-y

IFN-y activates macrophages

138
Q

A 50 yo patient presents with a heart murmur, bounding femoral pulses and carotid pulsations that are accompanied by head-bobbing. Disease/Dx?

A

Aortic regurgitation

139
Q

Stimulation of what nerve has been used as a potential treatment for obstructive sleep apnea?

A

Hypoglossal nerve

Hypoglossal nerve stimulation causes the tongue to move forward slightly, increasing the diameter of the oropharyngeal airway (decreasing apnea)

140
Q

Aside from hygenic delivery, what is currently done to prevent neonatal tetanus infection?

A

Vaccination of pregnant women with TDaP

Immunized mothers provide passive immunity to infants via transplacental IgG (this protects infants until they receive their own immunization at age ~2 months)

141
Q

The main purpose of double blinding in clinical trials is to prevent what kind of bias?

A

Observer bias

Blinding prevents patient and researcher expectations from interfering with an outcome

142
Q

Patients have the right to refuse to receive medical information regarding diagnosis (or anything else). True or False?

A

True

Physicians must understand and respect different cultures that may not want to know about a diagnosis which may cause stress/depression/pain/etc.

143
Q

What are the two most common anatomic locations where the ulnar nerve may become injured?

A
  1. medial epicondyle of the humerus (“funny bone”)

2. Guyon’s canal near the hook of the hamate bone

144
Q

In what state of acetylation will histones prevent replication/transcription of DNA?

A 
Deacetylated histones 
(maintain a tight hold on DNA wrapped in chromatin, preventing DNA replication/transcription)
145
Q

What enzyme carries out nucleotide excision repair following DNA damage such as thymine dimers formation due to UV light exposure?

A

Endonuclease

Endonuclease recognizes distortions in the structure of DNA caused by thymine dimers and excises the damaged DNA containing defects

146
Q

Wide, fixed splitting of the second heart sound (S2) is associated with what heart defect?

A

Atrial septal defect (ASD)

147
Q

Valine, alanine and isoleucine are examples of what kind of amino acids?

A

nonpolar, hydrophobic amino acids

These amino acids carry no charge

148
Q

Contact dermatitis, granulomatous inflammation, tuberculin skin test and Candida extract skin reaction are examples of what type of immune reaction mediated by what immune cell?

A

Delayed-type hypersensitivity reaction (Type IV)

The cells mediating this type of immune reaction are T cells (Th1 specifically)

149
Q

What is the most posterior part of the heart?

A

Left atrium

Enlargement of the left atrium can cause dysphagia due to pressure on the esophagus

150
Q

Patient presents with a sore on his leg that appears to be an ulcer with central black eschar and surrounding edema. Culture reveals chains of large Gram-positive rods. Disease/Dx?

A

Bacillus anthracis infection

Cutaneous anthrax is most commonly contracted through exposure to infected animals or animal products

151
Q

Explain the mnemonic for the femoral triangle AND how to properly apply this medially to laterally.

A

VAN - Vein -> Artery -> Nerve (all femoral)

The femoral vein is most medial and the femoral nerve is most lateral

152
Q

What role does carnitine play in biochemisty?

A

Carnitine is responsible for transport of fatty acids into the mitochondria (from the cytosol) for beta-oxidation of fatty acid

153
Q

What is the difference between Schizoid and Schizotypal personality disorder?

A

Schizoid - prefers to be a loner, detached, unemotional

Schizotypal - eccentric; odd thoughts, perceptions and behaviors, social anxiety

154
Q

Patients with chronic granulomatous disease experience frequent reinfection by organisms that have what characteristic?

A

Catalase positive organisms

catalase positive organisms can destroy hydrogen peroxide

155
Q

How do you calculate the alveolar-arterial (A-a) gradient and what is the A-a gradient in a healthy person?

A

A-a gradient = Alveolar O2 - Arterial O2

A-a gradient in a healthy person is 5-15 mmHg (a normal A-a gradient can help rule out certain types of hypoxemia)

156
Q

What (2nd line) treatment is in patients with gout that cannot take NSAIDs due to renal failure or peptic ulcer disease?

A

Colchicine

Colchicine inhibits tubulin polymerization and microtubule formation in leukocytes, reducing the inflammatory response (this also causes diarrhea, nausea and vomiting)

157
Q

How long does it take to reach steady state concentration for a given first-order kinetic drug?

A

4-5 half-lives (during continuous infusion)

158
Q

What is the most common type of kidney stone?

A

Calcium stone

usually due to hypercalciuria

159
Q

What is the single most preventable cause of death and disease in the United States?

A

Smoking (tobacco)

On lifestyle modification questions, the answer is almost always smoking cessation

160
Q

What hormone is responsible for gallbladder contraction?

A

Cholecystokinin

Its main functions are to:

  1. increase pancreatic enzyme secretion
  2. gallbladder contraction
  3. decrease gastric emptying

(fatty foods increase CCK production/release)

161
Q

In males, incomplete fusion of the urethral (urogenital) folds results in what congenital abnormality?

A

Hypospadias

A urethral opening on the ventral (underside) of the penis)

162
Q

A 1 yo female presents with recurrent, pus-less skin infections and gingivitis. The patient also had delayed separation of the umbilical cord for 10 weeks following delivery. Disease/Dx?

A

Leukocyte adhesion deficiency

  • autosomal recessive genetic absence of CD18
  • inability to synthesize integrins resulting in a defect in leukocyte ability to adhere to endothelium and exit bloodstream
  • highly associated with delayed detachment of umbilical cord
163
Q

What statistical test is used to compare the difference between the means of 2 groups? and 2 or more groups?

A

2 group - Two-sample t-test

2 or more groups - Analysis of variance

164
Q

How is net filtration calculated?

A

Net filtration = (difference in hydrostatic pressure) - (difference in oncotic pressure)

165
Q

What is characteristic of the psychologic defense mechanism splitting?

A

Seeing others as all bad or all good; all or nothing thinking

166
Q

What physiologic effect do nitrites have on blood?

A

Nitrites cause poisoning by converting reduced ferrous (Fe2+) heme to the oxidized ferric (Fe3+) state

Fe3+ heme, called methemoglobin, is unable to bind oxygen (resulting in a functional anemia)

167
Q

What are the name of antigen presenting cells that possess tennis racket shaped intracytoplasmic granules?

A

Langerhans cells (tennis racket inclusions are Birbeck granules)

Langerhans cells are dendritic cells found in the skin

168
Q

What complication may occur following a scaphoid bone fracture, typically occurring after a person falls with an outstretched hand?

A

Avascular necrosis (due to little blood supply to this area)

169
Q

What is the most common complication following a varicella zoster virus (reactivation) infection?

A

Persistent dermatomal pain that may persistent for several months (post-herpetic neuralgia)

170
Q

What ion channel do Class 3 antiarrhymics block?

A

Potassium (K+) channels

This prolongs phase 3 of the cardiomyocyte action potential, slowing repolarization

171
Q

What amniotic fluid marker ~35 weeks gestation indicates appropriate fetal lung maturity?

A

lecithin (phosphatidylcholine)/sphingomyelin ratio > 2.0

Lecithin (phosphatidylcholine) production increases sharply in the 3rd trimester while the sphingomyelin level remains unchanged

172
Q

What test can be used to diagnose abnormal hemoglobin in patients with thalassemia, sickle cell disease/trait or hemoglobin C disease/trait?

A

Hemoglobin electrophoresis

173
Q

What tissue in the body has the highest oxygen extraction from blood?

A

Cardiac muscle (myocardium)

174
Q

What bacterial pathogens can cause necrotizing fasciitis?

A

Staph aureus, Strep pyogenes and Clostridium perfringens are most common

S. aureus (G+ cocci, catalase +, coagulase +)
S. pyogenes (G+ cocci, catalase -, coagulase -)
C. perfringens (G+ rod/bacilli, obligate anaerobe)

175
Q

Nitrates are used to treat chronic stable angina and cause systemic vasodilation. Do nitrates predominantly vasodilate arterial or venous vessels?

A

Nitrates preferentially dilate VEINS

calcium channel blockers preferentially dilate arteries

176
Q

What treatment is provided to people with potential exposure to radioactive iodine-131 following nuclear reactor accidents to prevent tissue damage?

A

Potassium iodide (prevents thyroid carcinoma)

Potassium iodide competitively inhibits thyroid uptake of the radioactive iodine

177
Q

What occurs with a missense mutation?

A

Single base substitution

Missense mutations are seen in sickle cell and hemoglobin C disease in which a single base substitution results in a codon for a different amino acid

178
Q

What occurs with a silent mutation?

A

Silent mutations are point mutations that have NO EFFECT on the protein formed

179
Q

What occurs with a frameshift mutation?

A

Frameshift mutations occur with the deletion or insertion of base pairs that are NOT A MULTIPLE OF 3

180
Q

What occurs with a nonsense mutation?

A

Nonsense mutations INTRODUCE A STOP CODON, truncated proteins

181
Q

What anatomical landmark can be used to distinguish between direct and indirect inguinal hernias?

A

Inferior epigastric vessels (essentially run down the middle)

Indirect (lateral) - Inferior epigastric - Direct (medial)

182
Q

What are the classic symptoms of hyperparathyroidism?

A

Bone pain, renal stones, GI disturbances, depression

“stones, bones, abdominal groans, and psychic moans”

183
Q

Concerning RAAS, where in the body is inactive angiotensin I converted into active angiotensin II?

A

AT I is converted to AT II by angiotensin-converting enzymes in the LUNGS

184
Q

A 13 month old girl presents with initially normal development but has recently regressed via a loss of babbling, inability to sit up, deceleration of head growth and constant movements of twisting hands together. Disease/Dx?

A

Rett syndrome

(characterized by loss of speech and motor skills, deceleration of head growth and stereotypic hand movements after a period of normal development - mainly in girls)

185
Q

What G protein-coupled receptor do TSH, glucagon and PTH act on?

A

Gs receptor

activates protein kinase A, increases intracellular cAMP

186
Q

In statistics, what is the Hawthorne effect?

A

The tendency of study subjects to change their behavior as a result of their awareness that they are being studied (observer effect)

187
Q

It is OK for physicians to accept expensive gifts from patients. True or False?

A

FALSE

It is ethically problematic for physicians to accept expensive gifts and should be declined (though small value gifts or cards are OK)

188
Q

What hormone causes the closure of epiphyseal plates (growth plates) during puberty?

A

Estrogen

Estrogen initially increases linear bone growth but eventually stimulates the closure of epiphyseal growth plates

189
Q

What drug is used to treat open-angle and closed-angle glaucoma that has physiologic action in both the eye and the kidney? What is its mechanism of action?

A

Acetazolamide - inhibits carbonic anhydrase

In the kidney - this blocks HCO3- reabsorption in the proximal tubule, alkalinizing urine (↑ pH)

In the eye - this decreases HCO3- and aqueous humor formation, relieving intraocular pressure

190
Q

What congenital heart defect is associated with children squatting to make themselves “feel better”?

A

Tetralogy of Fallot

Squatting increases systemic peripheral resistance (↑ afterload) and decreases right to left shunting

191
Q

What type of exocrine gland is responsible for acne?

A

Holocrine glands (sebaceous glands are a type of holocrine gland)

192
Q

What two places in the body are B1 adrenergic receptors predominantly found?

A

Cardiac tissue and renal juxtaglomerular cells

Cardiac tissue - increases heart rate / contractility
Juxtaglomerular cells - increases renin release (↑ BP)

193
Q

What is first-line treatment for panic disorder (recurrent panic attacks)?

A

SSRIs

benzodiazepines can also be used

194
Q

Sore throat, diffuse erythematous rash and strawberry tongue are associated with infection by what bacteria?

A

Strep pyogenes (Group A Strep)

These symptoms describe scarlet fever

195
Q

What is the difference between first generation and second generation antihistamines?

A

First gen antihistamines block H1 receptor in peripheral tissues AND the CNS (can cross BBB)

Second gen antihistamines block H1 receptors ONLY in the peripheral tissues (can’t cross BBB)

196
Q

In statistics, what is characteristic of a reliable test?

A

Reproducible; it gives similar or very close results on repeat measurements

(basically synonymous with precision)

197
Q

What is the difference between ribosomes attached to the RER and ribosomes freely floating in the cytosol?

A

Ribosomes synthesize proteins

Ribosomes attached to the RER synthesize proteins that are destined for the cell membrane or secretion/export from the cell

Ribosomes freely floating in the cytosol synthesize proteins that remain in the cytosol or other inner cell regions

198
Q

What medication should be prescribed to patients experience transient ischemic attacks (brain) or stable angina in addition to antihypertensives and statins?

A

Aspirin!

Aspirin prevents platelet synthesis of thromboxane A2 which impairs platelet aggregation, reducing the risk of clot formation

199
Q

What is the function of primase?

A

Primase is a DNA-dependent RNA polymerase that synthesizes the short RNA primers which DNA polymerase utilizes as a starting point for DNA replication

200
Q

What complications can arise from chronic obstructive sleep apnea?

A

Systemic hypertension and eventually pulmonary hypertension and right heart failure

(due to blood gas fluctuations from the transient hypoxic states)

201
Q

What type of abnormality occurs in Ehlers-Danlos syndrome?

A

Abnormal collagen formation

This manifests as hypermobile joints, overelastic skin and fragile tissue susceptible to bruising

202
Q

A patient presents to clinic with an abnormal gait. On examination of gait, the patient leans to his right side while walking. When standing on the right leg, the patient’s left hip tilts downward. What nerve is injured?

A

Superior gluteal n.

This nerve innervates the majority of gluteus muscles and stabilizes the pelvis. With nerve injury, the muscles cannot contract and so the patient is essentially walking with a peg leg on one side

203
Q

12 month old male presents with eczema, increased bleeding time, petechiae and a history of recurrent, severe respiration infections. Disease/Dx?

A

Wiskott-Aldrich syndrome

WATER: Wiskott-Aldrich, Thrombocytopenia, Eczema, Recurrent infections (B and T cell deficiency)

204
Q

Does total systemic vascular resistance increase or decrease with exercise?

A

DECREASE (even though BP increases)

Vasodilation within active skeletal muscle (B2) to increase perfusion to exercising muscles actually decreases the total systemic vascular resistance

205
Q

A patient presents a week after dislocating their right shoulder playing flag football. The patient has trouble elevating (abducting) his right arm and has diminished sensation over the deltoid muscle/upper lateral arm. What nerve has been injured?

A

Axillary nerve

Axillary nerve injury occurs commonly in the setting of shoulder trauma

206
Q

Prior to prescribing amiodarone (class III AR), what functional tests should be ordered due to potential adverse effects?

A

Pulmonary, Liver and Thyroid function tests

Amiodarone can cause adverse effects in all of these organs

207
Q

What volume of distribution is larger in the body, fat or water?

A

Fat (41 L) is vastly larger

water is ~14 L, 3 L of which is plasma volume

208
Q

What is the most dangerous adverse effect of Amphotericin B?

A

Nephrotoxicity

This can lead to anemia (↓ EPO production by kidney) and hypokalemia (causing weakness and arrhythmias)

209
Q

What effects can dopamine have on the autonomic nervous system?

A

Dopamine is an adrenergic agonist (sympathetic)

At low doses, dopamine can stimulate B1 receptors

At high doses, dopamine can stimulate a1 receptors

210
Q

What is the 1st line therapy for recurrent gout attacks (gouty arthritis, uric acid renal stones, etc.)?

A

Xanthine oxidase inhibitors (allopurinol, febuxostat)

-these drugs decrease uric acid production

211
Q

9 year old girl presents with diplopia and headaches. A brain MRI shows a cystic, suprasellar lesion with calcifications. Disease/dx?

A

Craniopharyngioma

Craniopharyngioma is derived from remnants of Rathke’s pouch (embryologic predecessor of anterior pituitary)

212
Q

A 45 yo male kidney transplant recipient presents with fever, night sweats, patchy lung crackles and lethargy. Brain MRI shows 2.0cm ring-enhancing focal lesion. Gram stain shows branching filaments of gram-positive rods. Disease/Dx?

A

Nocardia asteroides infection

Nocardosis typically affects LUNGS (similar to TB), BRAIN (abscess) and SKIN

213
Q

What is the importance of the marginal artery, an artery found supplying the intestinal tract?

A

The marginal artery serves as an anastomosis between the superior and inferior mesenteric arteries

214
Q

In sickle cell disease, what physiologic condition promotes aggregation and sickling of the HbS RBCs?

A

LOW OXYGEN state (or anything associated with hypoxia such as ↓ pH)

215
Q

What is the most anterior part of the heart?

A

Right ventricle (mostly)

216
Q

What is carbolfuchsin dye used for?

A

Acid-fast staining

Acid-fast staining identifies organisms with mycolic acid present in their cell walls which includes Mycobacterium and Nocardia

217
Q

What is akathisia?

A

An extrapyramidal side effect of antipsychotic medication characterized by INNER RESTLESSNESS and an INABILITY TO SIT STILL

218
Q

Irregular periods resulting from polycystic ovary syndrome can propagate what serious complication?

A

Endometrial carcinoma

Menstrual irregularity results in decreased progesterone secretion, a hormone that counters estrogen-driven proliferation of the endometrium

219
Q

On light microscopy of lung tissue from a patient that experienced chronic dyspnea, alveolar macrophages containing golden cytoplasmic granules that turn dark blue with Prussian blue staining are found. What are the granules in the macrophages?

A

Hemosiderin (containing IRON)

Prussian blue stain detects intracellular iron

220
Q

What types of tumors/cancers are associated with psammoma bodies?

A

PSaMMoma

Papillary carcinoma of thyroid
Serous papillary carcinoma of the ovary / endometrium
Meningioma
Malignant mesothelioma

221
Q

What is the drug of choice for patients that experience absence seizures (staring blankly) AND tonic-clonic seizures (violent shaking)?

A

Valproate

Valproate can treat BOTH absence and tonic-clonic seizures

222
Q

Describe hypoxic vasoconstriction and where it occurs.

A

Hypoxic vasoconstriction occurs in the LUNGS

In pulmonary vascular bed, tissue hypoxia results in vasoconstriction. This allows for blood to be diverted away from underventilated regions of the lung toward better-ventilated areas.

223
Q

What cranial nerves are involved in the pupillary light reflex?

A

CN II (optic) - AFFERENT limb of pupillary reflex

CN III (oculomotor) - EFFERENT limb of pupillary reflex

224
Q

What symptoms are seen in a cranial nerve III palsy?

A

Ptosis (drooping eyelid)
“down and out” gaze (unopposed CN IV and VI action)
Fixed, dilated pupil and loss of accommodation

225
Q

What types of drugs or foods can precipitate G6PD deficiency hemolytic anemia?

A

Sulfa drugs, antimalarials, dapsone, fava beans

226
Q

What is the most important component of therapy for a person with active diphtheria infection?

A

Administering ANTI-TOXIN (passive immunization)

While antibiotics may help in the long run (prevents production of new exotoxin), anti-toxin is needed to dispose of currently circulating exotoxin

227
Q

Carotid sinus massage causes an autonomic nervous system response via what mechanism?

A

Carotid sinus massage leads to INCREASED baroreceptor firing rate leading to an increase in PARASYMPATHETIC tone

228
Q

What three effects does parasympathetic activity have on the heart?

A

↓ heart rate at SA node
↓ contractility of the heart
↓ conduction velocity at the AV node (prolongs AV nod refractory period)

229
Q

What is the most common substance causing overdose death in the United States?

A

Opioids

230
Q

What does the pulmonary capillary wedge pressure measure?

A

Left atrial pressure

231
Q

On auscultation, a holosystolic murmur is heard that is loudest over the left mid-sternal border. What is the cause of the murmur?

A

Ventricular septal defect

most common congenital heart defect

232
Q

What are the possible toxic effects of furosemide (loop diuretic)?

A

OH DANG!

Ototoxicity
Hypokalemia
Dehydration
Allergy (furosemide is sulfa drug)
Nephritis (interstitial)
Gout
233
Q

In what ways are beta blockers therapeutic for thyrotoxicosis (severely increased thyroid hormone in circulation)?

A
  1. decrease catecholamine action at beta-adrenergic receptors
  2. decrease the rate of peripheral conversion of T4 to the more active T3
234
Q

Niacin can be synthesized in the body but requires what precursor molecule?

A

Tryptophan

Niacin deficiency results in pellagra - 3 D’s

235
Q

What are clinical features of post-traumatic stress disorder (PTSD)?

A

Exposure to a significantly traumatic event (life threatening)
Nightmares, flashbacks, intrusive memories
Avoidance of reminders of the event
Emotional detachment, negative mood
Decreased interest in activities
Sleep disturbance, irritability, hypervigilance

236
Q

Describe 5 of the symptoms used to diagnose schizophrenia (need >2)

A 
Delusions
Hallucinations
Disorganized speech
Grossly disorganized behavior (bizarre behavior)
Negative symptoms (flat affect)
237
Q

What is the function of calcineurin?

A

Calcineurin is an essential protein in the activation of IL-2, which ultimately promotes growth and differentiation of T cells

238
Q

How does Hepatitis B (or any hepatitis) cause damage to hepatocytes?

A

HBV does NOT! have a cytotoxic effect

The presence of viral HBsAg and HBcAg on the cell surface of infected hepatocytes stimulates host CD8+ T cells to destroy infected hepatocytes

The CD8 IMMUNE RESPONSE causes the liver injury

239
Q

What is a common adverse effect of lamotrigine (Na+ channel blocker for generalized seizures) that can develop into a more severe complication?

A

Skin rash; typically benign but a life-threatening rash can be caused by Stevens-Johnson syndrome

240
Q

CYP450 Inducers (increase drug metabolism)

A 
Carbamazepine
Phenobarbital
Phenytoin
Rifampin
Griseofulvin
241
Q

CYP450 Inhibitors (decrease drug metabolism)

A 
Cimetidine
Ciprofloxacin
Erythromycin
Azole antifungals
Grapefruit juice
Isoniazid
Ritonavir (protease inhibitors)
242
Q

A patient presents weeks after lower right leg injury in a floor hockey game. On examination, the patient has reduced sensation of the dorsum of the foot and lateral shin and displays “foot drop” while walking. What nerve injury is responsible for these findings?

A

Common peroneal nerve injury

This is the most commonly injured leg nerve

243
Q

What is a common side effect of topical corticosteroid use?

A

Dermal atrophy - corticosteroids decrease the production of extracellular matrix collagen

244
Q

What medical therapy is used for severe sickle cell anemia?

A

Hydroxyurea

Hydroxyurea increases fetal hemoglobin (Hb F) production which reduces polymerization (sickling) of sickle cells

245
Q

What virus is particularly problematic in patients with sickle cell and other hemolytic disorders?

A

Parvovirus B19 (infects erythroid precursor cells)

Parvovirus B19 can cause aplastic crisis in which the patient is unable to produce new RBCs

246
Q

What causes the early transient hypercoagulable state when warfarin therapy is started?

A

Protein C and S (anticoagulants) have shorter half-lives than the VitK dependent clotting factors II, VII, IX, and X

Because of this, there is a coagulant/anticoagulant imbalance for a short period of time, resulting in a hypercoagulable state

247
Q

Recurrent infections with Neisseria species (many bouts of meningitis) may be indicative of what immune system deficiency?

A

Terminal complement deficiency (↓ C5-C9)

Patients deficient in C5-C9 complement cannot form the membrane attack complex and have recurrent Neisseria infections

248
Q

What enzyme deficiency is seen in Lesch-Nyhan syndrome and what pathogenesis does this result in?

A

Defective/absent hypoxanthine-guanine phosphoribosyltransferase (HGPRT)

This results in defective purine salvage/recycling leading to increased purine degradation and excess uric acid production

249
Q

In a female experiencing recurrent UTIs with eventual development of pyelonephritis in some cases, what is a predisposing factor to pyelonephritis?

A

Vesicoureteral urine reflux

Allows for retrograde flow of pathogens in the urine into the ureter, contributing to ascending infection
-frequent UTIs can contribute to development of vesicoureteral reflux

250
Q

What are the pathologic functions of toxin A and B of Clostridium difficile?

A

Toxins A and B disrupt the actin cytoskeletal structure and intracellular signaling

This disrupts the intercellular tight junctions allowing for intestinal fluid secretion

251
Q

When patients develop splenomegaly due to high amounts of hemolysis, what part of the spleen is enlarged?

A

Red pulp of the spleen (splenic parenchyma)

This area of the spleen contains reticuloendothelial cells involved in the removal of damaged RBCs

252
Q

What anatomic structure is fluid accumulating within in hydrocele?

A

Tunica vaginalis (can be due to patent processus vaginalis)

253
Q

What is the function of atrial and brain natriuretic peptides (BNP/ANP)?

A

ANP and BNP are both release in response to increases blood volume and blood pressure

They cause vasodilation and ↓ Na+ reabsorption in kidneys

Act via cGMP (relaxation of vascular smooth muscle)

254
Q

What immunologic function does Leukotriene B4 serve?

A

Chemotaxis - stimulates neutrophil migration to sites of inflammation

(as does C5a and IL-8)

255
Q

What molecule is a precursor for serotonin?

A

Tryptophan (for niacin as well)

256
Q

What gram-negative bacilli, lactose fermenting (pink on MacConkey), encapsulated infectious agent is highly associated with pneumonia in alcoholics and immunocompromised?

A

Klebsiella pneumoniae

also associated with thick, mucoid, blood-tinged sputum - currant jelly sputum

257
Q

What area of the brain is the first area damaged during global cerebral ischemia (from cardiac arrest, for example)?

A

Hippocampus

258
Q

What is the most common cause of an irregularly irregular rhythm, detected on ECG as an absence of organized P waves?

A

Atrial fibrillation

259
Q

A 70 yo man presents to clinic with persistent back pain. On examination it appears the pain is acutely due to bone pain in multiple vertebrae. Imaging indicates increased activity in these vertebrae due to osteoblastic activity. A metastatic cancer is suspected. Disease/Dx?

A

Metastatic prostate cancer

260
Q

What malignancies are associated with Epstein-Barr virus (infectious mononucleosis)?

A

Burkitt lymphoma
Hodgkin lymphoma
Nasopharyngeal carcinoma

261
Q

What co-morbidities are associated with coarctation of the aorta?

A

Turner syndrome
Bicuspid aortic valve (assc. w/ Turner syndrome)
Congenital berry aneurysms in Circle of Willis (adult-type)

262
Q

What is a common complication of subarachnoid hemorrhage resulting from a ruptured saccular/berry aneurysm?

A

Vasospasm (> 50% experience)

Typically occurs 4-12 days after rupture and can cause additional cerebral ischemia

USMLE Step 1 (7 decks)

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