Blocks 43, 44 Flashcards Preview

UWORLD STEP 1 > Blocks 43, 44 > Flashcards

Flashcards in Blocks 43, 44 Deck (71):
1

18 month old boy with a normal development until 5 months of age. Gradual regression of developmental milestones like inabililty to sit without support, poor head control, and loss of a social smile. Enlarged spleen and liver, diminshed deep tendon reflexes in all limbs, hypotonia, cherry red macula.

Neimann-Pick disease

AR

Sphingomyelinase deficiency --> sphingomyelin accumulation within lysosomes (look like lipid laden foam cells)

2

An elevated creatinine kinase (CK) is highly suggestive of what underlying problem?

Myopathy

Due to direct myocyte damage and leakage of muscle enzymes into the circulation

3

Common causes of myopathy with elevated CK

Hypothyroidism

Muscular dystophies

Inflammatory muscle diseases

Medications like statins

Autoimmune diseases (polymyositis, dermatomyositis)

4

Muscle pain and stiffness in shoulder, neck, and pelvic girdle. Worse in the morning and with activity. Normal Creatinine Kinase

Polymyalgia rheumatica

5

What drug should be given to a patient with recurrent calcium oxalate stones?

Thiazides (hydrochlorothiazide)

They effectively increase calcium reabsorption from the nephron

6

34 y/o man with severe chest and abdominal pain then suffers a cardiac arrest with pulseless electrical activity, internal hemorrhage was the COD. Autopsy shows a defect in a large extracellular glycoprotein normally found in abundance in large blood vessels, periosteum, and zonular fibers of the lens and functions to form microfibrils by surrounding elastin.

Marfan Syndrome

Defect in Fibrillin-1 - a major component of microfibrils that form a sheath around elastin fibers.

Heart = aortic dilation, regurgitation, or dissection, mitral valve prolapse

7

What drug decreases intestinal absorption of cholesterol by inhibiting the neimann-pick C1-like 1 (NPC1L1) transporter protein, which transports dietary cholesterol from the brush border of the small intestine?

Ezetimibe

8

In a person with Cyanide poisoning, the use of amyl nitrite has what effect?

It oxidizes ferrous (Fe2+) in hemoglobin to ferric (Fe3+), generating methemoglobin which is incapable of carrying oxygen but has a high affinity for cyanide so it sequesters cyanide in the blood, freeing it from cytochrome oxidase and limiting it's toxic effects.

9

Other than amyl nitrite, what substances can be used as antidotes for cyanide poisoning?

Hydroxycobalamin (vit B12 precursor)

Sodium thiosulfate

10

What step in Vitamin D metabolism is directly affected by being in the sun?

Conversion of 7-dehydrocholesterol to Cholecalciferol

11

Newborn with intracranial, gastrointestinal, cutaneous, umbilical, or surgical site bleeding. What is lacking?

Vitamin K

Babies should be given intramuscular vitamin K because there is low vit K at birth due to poor placental transfer, low content in breast milk, and a sterile gut.

Vit K is critical for carboxylation of clotting factors 2, 7, 9, 10

12

Child with spontaneous by painless lower GI bleeding. Tc-pertechnetate localizes ectopic gastric mucosa and it's increased uptake is diagnostic for what?

Meckel Diverticulum

Failed obliteration of the vitelline (omphalomesenteric) duct

13

Colicky abdominal pain with currant jelly (strawberry jam appearance) stools.

Intussusception

(meckel diverticulum can lead to this)

14

A frontal lobe lesion on what side causes apathy and depression?

Left-sided frontal lobe

15

A frontal lobe lesion on what side causes disinhibited behavior?

Right-sided frontal lobe lesion

16

Femoral hernias are between what 3 structures?

Inferior to the inguinal ligament

Lateral to the pubic tubercle

Medial to the femoral vein

17

What is the most important environmental risk for pancreatic cancer?

Smoking

18

von Willebrand factor serves what 2 roles in hemostasis?

1. Promotes platelet adhesion at sites of vascular injury by binding to and crosslinking platelet glycoproteins (primarily Gp 1b) with exposed collagen underneath damaged endothelium. 

2. Protective carrier protein for factor 8 that increases it's plasma half-life

19

Langhans giant cells are characteristic of granulomatous conditions, including the caseating granulomas associated with Mycobacterium tuberculosis infections. The macrophages that form these giant cells are activated by what?

CD4+ Th1 Lymphocytes

20

Chronic antral inflammation leads to a decrease in the number of somatostatin-producing cells (delta cells). What will be the result?

Decreased Somatostatin

Uninhibited gastrin release

Increased hydrogen ion secretion by parietal cells

Duodenal ulceration and duodenal gastric metaplasia

21

What are the common side effects of ACE inhibitors?

Decreased GFR

Hyperkalemia

Cough

Angioedema (rare but life threatening)

22

What is the course of the ureters and what structures are near them?

Within retroperitoneum just anterior to the psoas muscles. Midway from the kidnes to the pelvic inlet, gonadal artery and vein cross over the anterior surface of the ureter.

The ureters gain access to the pelvis by crossing over the anterior surface of the common iliac artery near its bifurcation into the internal and external iliac arteries. At this point, the ureter lies medial to the ovarian vessels and anterior to the internal iliac artery.

23

MOA of combined hormonal contraceptive pills?

Suppress GnRH and pituitary gonadotropin secretion, inhibiting ovulation

24

Acute coronary syndrome occurs due to plaque rupture, which leads to superimposed thrombosis and vessel occlusion. The likelihood of plaque rupture largely depends on the mechanical strength of the fibrous cap. What characterizes low strength?

Thin-cap fibroatheromas have large necrotic core covered by a thin fibrous cap. Activated macrophages infiltrating the atheroma contribute to the breakdown of ECM by secreting metalloproteinases. Ongoing intimal inflammation can destabilize the mechanical integrity of the plaque through release of these metalloproteinases, resulting in plaque rupture and consequent acute coronary syndrome.

25

What is the MOA of Acyclovir?

Complete inhibition of the viral DNA polymerase

26

What is the most characteristic skeletal manifestation of primary hyperparathyroidism? How does it present?

Osteitis fibrous cystica

Bone pain, subperiosteal erosions affecting the phalanges of the hand and a salt and pepper skill, and brown tumor bone cysts.

27

What mutation leads to constitutive activation of the epidermal growth factor receptor pathway, promoting increased cell proliferation and growth?

Activating mutations of the KRAS gene

28

What is the difference between major depressive disorder and persistent depressive disorder?

Persistent = at least 2 years 

Major = at least 2 weeks

29

Painful thyroid enlargement following a viral illness. Pts experience a transient hyperthyroid phase due to release of stored thyroid hormone. What is the diagnosis and what does biopsy show?

Subacute granulomatous (de Quervain) thyroiditis

Biopsy = lymphocytic infiltrate with macrophages and multinucleated giant cells

30

Rivaroxaban and Apixaban are oral anticoagulants that work on what?

Directly inhibits factor Xa

Used in venous thromboembolism and a-fib

31

What is the treatment of choice for DKA? What are the lab changes after treatment?

Intravenous normal saline and insulin

Increase serum bicarb and sodium, decrease serum glucose, osmolality, and potassium

32

A pt. with a persistent belief that he is being poisoned, general function is not disturbed. No presence of psychotic symptoms like hallucinations. (greater than 1 month in duration)

Delusional Disorder

33

If a right to left intracardiac shunt is found what are the 2 most common lesions that would cause this?

1. Atrial Septal Defect

2. Patent Foramen Ovale

34

A patent foramen ovale remains functionally closed and therefore asymptomatic unless what would happen?

Conditions that raise the right atrial pressure above the left atrial pressure (valsalva) can produce a transient right to left shunt across the PFO that may result in a paradoxial embolism (stroke in the setting of venous thromboembolism)

35

54 y/o previously healthy man with 2 months of progressive, generalized weakness and easy fatigability, abdominal discomfort, early satiety, afebrile, pallor, abdominal distension, massive splenomegaly with the spleen tip crossing the midline, pancytopenia, dry tap on bone marrow aspiration.

Hairy Cell Leukemia

Lymphocytes with cytoplasmic projections

Predominantly middle aged men

Fibrosis --> pancytopenia

Dry tap

Massive splenomegaly

Flow cytometry has replaced TRAP staining for diagnosis

36

What is found on autopsy/histo after an amniotic fluid embolism?

Fetal squamous cells and mucin in the maternal pulmonary arteries

37

What bleeding disorder will cause a prolonged PTT and bleeding time?

von Willebrand Disease 

AD with variable penetrance

Most common heritable bleeding disorder.

 

38

What is a carrier protein for factor 8 and a mediator of platelet adhesion to the endothelium?

Von Willebrand Factor

39

A transmural infarction is most commonly caused by what events?

Acute plaque change (rupture) which produces a superimposed thrombus that completely occludes the involved coronary artery.

40

What are the 3 aspects of MEN 1?

3 Ps

Primary hyperparathyroidism (hypercalcemia)

Pituitary tumors (prolactin, visual defects)

Pancreatic tumors (gastrinomas)

41

What are the 3 aspects of MEN 2A?

PPM

Pheochromocytoma

Parathyroid hyperplasia

Medullary thyroid cancer (calcitonin)

42

What are the 3 aspects of MEN 2B?

PMM

Pheochromocytoma

Medullary Thyroid Cancer (calcitonin)

Mucosal neuromas/marfanoid habitus

43

What antifungals bind to ergosterol molecules in fungal cell membranes, creating pores and causing cell lysis?

Polyenes:

Amphotericin B

Nystatin

44

What antifungals inhibit synthesis of ergosterol?

Azoles

45

What antifungals inhibit the synthesis of glucan, a component of the fungal cell wall?

Echinocandins:

Caspofungin

Micafungin

46

What antifungal is converted to 5-FU within the fungal cell and interferes with fungal RNA and protein synthesis?

Pyrimidines: Flucytosine

47

Pt with perifollicular hemorrhages, myalgias, subperiosteal hematoma, and gingivitis

Scurvy

Deficient ascorbic acid (Vit C)

C is important in the hydroxylation of proline and lysine residues (needed for collagen synthesis)

48

What vitamin deficiency leads to angular stomatitis, cheilitis, glossitis, seborrheic dermatitis, eye changes (keratitis, corneal neovascularization), and anemia?

B2 - Riboflavin

49

What deficiency causes acrodermatitis enteropathica, growth retardation and infertility?

Zinc Deficiency

50

Arterial blood supply to the myocardium is provided by the right and left coronary arteries arising directly from the aortic root during what?

Diastole

When HR goes up, duration of diastole goes down --> major limiting factor for coronary blood supply to the myocardium

51

Under hypoxic conditions, intracellular accumulation of NADH inhibits what enzyme of glycolysis? What way pyruvate shunted?

Pyruvate Dehydrogenase is inhibited

Pyruvate goes to lactic acid (via lactate dehydrogenase)

With significant tissue ischemia, lactate begins to accumulate in the circulation and can lead to lactic acidosis.

52

Riboflavin is a precursor of what coenzymes? Where are they important?

FMN and FAD

FAD acts in the TCA cycle and electron transport chain as an electron acceptor for succinate dehydrogenase (succinate --> fumarate)

53

The common cardinal veins of a developing fetus give rise to what?

SVC and other constituents of the systemic venous circulation

54

Overdose findings: mental status changes (delirium, drowsy, coma), seizures, respiratory depression, tachycardia, hypotension, arrythmias, dry mouth, blurry vision, dilated pupils, flushing, hyperthermia.

TCAs

Due to blockage of cardiac fast sodium channels and inhibition of muscarinic acetylcholine, histamine, and alpha-1-adrenergic receptors

Treat = Sodium Bicarb

55

Which MHC class  is loaded with antigen taken into an APC within acidified endosomes and then expressed on the cell surface for subsequent interaction with T lymphocytes?

MHC 2

56

Sickle cells patients are at an especially increased risk of infection by what organisms? 

Encapsulated organisms because they are asplenic!

Strep Pneumo

H. Flu

If a sickle cell patient is septic, pick one of these.

57

Elderly woman with abdominal pain/distention, nausea/vomit, high-pitched (tinkling) bowel sounds, tenderness to palpation, dilated loops of bowerl with air-fluid levels, air in biliary tree (pneumobilia). (symptoms of a small bowel obstruction.... but that isn't what she has)

Gallstone ileus

Formation of a cholecysteneric fistula between the gallbladder and adjoining gut. Fistula formation allows passage of gallstone into small bowel, where it travels freely until it becomes trapped in the ileum (narrowest portion of intestine)

58

Benign leukocytosis (>50,000) that occurs in response to an underlying condition. Leukocyte alkaline phosphatase levels are normal or increased. What is this reaction and what is found on peripheral blood smear?

Leukemoid Reaction

Smear = increased bands, early mature neutrophil precursors (myelocytes), granules (dohle bodies - basophilic oval inclusions in mature neutrophils)

59

What is the pathogenesis of gallstones in a pregnant woman or a woman using OCPs?

Estrogen-induced cholesterol hypersecretion

Progesterone-induced gallbladder hypermotility

(FAT, FERTILE, FEMALE, FORTY)

60

How does Etanercept work?

TNF-alpha inhibitor added to methotrexate for RA

It is a fusion protein linking a soluble TNF-alpha receptor to the Fc component of human IgG1. It reduces the biological activity of TNF-alpha by acting as a decoy receptor.

61

What is the pathogenesis of amenorrhea in a woman with excessive weight loss, strenuous exercise, chronic illness, or an eating disorder? (functional hypothalamic amenorrhea)

Stepwise:

Decreased adipose tissue/fat reserves 

Decreased Leptin Production

Hypothalamus = decreased GnRH

Pituitary = decreased LH, FSH

Ovaries = decreased Estrogen

Amenorrhea, bone loss

62

A crycothyrotomy is indicated when an emergency airway is required and orotracheal or nasotracheal intubation is not available. What structures will be penetrated (out to in)?

Skin

Superficial cervical fascia (subQ fat + platysma muscle)

Investing and pretracheal layers of deep cervical fascia

Cricothyroid membrane

(all done between cricoid and thyroid cartilages)

63

An increasing prevalence and stable incidence can be attributed to what?

Factors that prolong the duration of a disease

64

The anthracycline chemotherapy agents (doxorubicin, daunorubicin, epirubicin, and idarubicin) have what SE on the heart?

Form free radicals in the myocardium

Cumulative dose-related dilated cardiomyopathy

(symptoms of left and right ventricular CHF)

65

Poisoning: abdominal pain, vomiting, severe watery diarrhea, hypotension, garlic odor to breath. Chronic = pigmentation change, hyperkeratosis, stocking glove neuropathy

ARSENIC

Mechanism: binds sulfhydryl groups and disrupts cellular respiration and gluconeogenesis

Sources: pesticides, contaminated water, pressure treated wood

Treatment = Dimercaprol

66

Carbon Monoxide poisoning has what effect on these values:

Carboxyhemoglobin

PaO2

Methemoglobin

Carboxyhemoglobin = elevated

PaO2 and Methemoglobin = normal

67

Small cell carcinoma of the lung (oat cell) is the most aggressive type of lung cancer. What is it's origin and what markers could be seen?

Neuroendocrine origin

Neuroendocrine markers: neural cell adhesion molecule (NCAM aka CD56), neuron-specific enolase, chromogranin, synaptophysin

68

Colitis associated carcinoma is more likely to:

1. Affect younger pt

2. Start from flat and non-polypoid dysplasia

3. Appear mucinous or be signet ring

4. early p53 mutations, late APC mutations

5. In prox colon

6. Be multifocal

69

6 y/o boy with recurrent sinopulmonary and gastrointestinal infections, failure to thrive, and evidence of defective signaling between CD4+ T cells and B cells

Hyperimmunoglobulin M Syndrome

Defect in class switching in B lymphocytes due to defective CD40-CD40L interaction

X linked recessive deficiency of CD40L is most common

70

34 y/o man: one week of inability to extend his right wrist and several of his fingers on the same hand. History of late onset asthma. Eosinophils elevated. Serum antibodies against neutrophil myeloperoxidase.

Eosinophilic granulomatosis with polyangiitis (Churg Strauss)

Asymmetric multifocal neuropathy (mononeuritis multiplex) is common due to the vasculits affecting the epineural vessels.

+p-ANCA

71

45 y/o man with groin pain and swelling. 1 month ago he had a sore on his penis (painless) that disappeared within a week. Now he has painful swelling in his inguinal region with inflammation overlying the skin and formation of several draining ulcers. Mild fever + malaise. Scrapings reveal cytoplasmic inclusion bodies.

Clamydia Trachomatis (L1-L3)

Lymphogranuloma Venereum (LGV)

Large, painful, coalesced inguinal lymph nodes (buboes)

Intracytoplasmic chlamydial inclusion bodies in epithelial cells and leukocytes

Treat = Doxy