Board Rounds Prep for USMLE and COMLEX

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22: What is Causing This Pancreatitis? Jun 26, 2019

Show notes

Session 22

Today, we tackle a pathophysiology question related to pancreatitis. Once again, we're joined by Dr. Karen Shackelford from BoardVitals. Check out their QBanks containing 1,700+ questions for Step1/Level 1. Use the promo code BOARDROUNDS to save 15% off.

[01:50] Question of the Week

A 45-year-old male presents to the hospital with abdominal pain and vomiting. He began to experience a dull pain in the epigastrium two days prior to admission that has progressively worsened. The pain radiates to his back.

He's had several episodes of bilious non-bloody vomiting. He has no prior medical conditions. And he takes no medications. He has a 20-pack per history of tobacco and drinks 6-10 beers daily.

The vital signs vary, has a temperature of 100 degrees Fahrenheit, and a heart rate of 102 beats per minute. He appears uncomfortable. On exam, his abdomen is soft and mildly distended, with marked right upper quadrant in epigastric tenderness to palpation. There is no rebound or guarding. He has hypoactive bowel sounds and no palpable masses or hepatosplenomegaly are appreciated.

Laboratory studies through the hemoglobin of 12.8 g/dL, leukocytes 14,500 cells per mm3, with 81% PMNs and 16% lymphocytes. Platelet count is 178,000 and total bilirubin is 1gm/dL with the direct bilirubin of 0.4 g/dL. Alkaline phosphatase is 90 IU/L and aspartate aminotransferase (AST) is 88, alanine aminotransferase is 78, and serum amylase is 1,447 IU/L.

What is one of the pathophysiological mechanisms of this patient's condition?

(A) Pancreatic duct obstruction due to a stone

(B) Activation of pancreatic stellate cells

(D) Intraductal stone formation

(E) Toxic fatty acids in pancreatic microcirculation

[04:00] Thought Process Behind the Correct Answer

Hemoglobin is normally low. White blood cells are minimally elevated. Platelets are normal. Bilirubin is a little bit elevated. Alkaline phosphatase is slightly elevated as well as the aspartate aminotransferase (AST), alanine aminotransferase and amylase.

The condition of the patient is actually pancreatitis. The lipase is also slightly elevated which is more specific for pancreatitis and amylase which can be released by other cells as well.

The most common cause of pancreatitis is gallstone pancreatitis but this guy has a history of pretty heavy drinking. The second most common cause of pancreatitis is related to alcohol.

It's not clear though exactly how they're related but most chronic alcoholics do not end up with chronic alcoholic pancreatitis. But there may also be other risk factors to be considered here.

One of the mechanisms is the hyperactivation of the pancreatic stellate cells. These cells that get activated by alcohol as well as by acetaldehyde. They regulate the deposition and the degradation of the pancreatic extracellular matrix protein. They secrete the matrix proteins and metalloproteinases that degrade the matrix proteins.

So they regulate all the extracellular matrix proteins in the pancreas. Whenever they're overactivated by phenol and acetaldehyde, the metabolite of ethanol, the matrix becomes fibrotic. That's one of the mechanisms of chronic pancreatitis.

Another interesting thing is that the stellate cells also express ADH and whenever overactivated, it seems to perpetuate a cycle of autocrine reactivation. So it's self-perpetuated.

Another mechanism of alcoholic pancreatitis is that the alcohol is metabolized by both oxidative and non-oxidative mechanisms. There are changes in acinar cells that increase the activation of intracellular digestive enzymes. Hence, there's an autodigestive component.

There is a transient decrease in pancreatic blood flow that results from the action of ethanol. 10:17 There's also an increase in ductal permeability related to alcohol use.

It then makes it possible for these improperly activated enzymes to leak out of the duct into the surrounding tissue which just adds to the inflammation and fibrosis.

Any of those mechanisms could be asked on the USMLE.

[11:00] Understanding the Other Answer Choices

It's not completely known what causes pancreatitis. After an obstruction, there's an increase in pancreatic pressure. Studies showed that the flow of biliary salts itself does not cause pancreatitis.

This patient doesn't have a previous history given the biliary colic. Bilirubin is relatively normal and patients with a stone obstruction usually have a direct hyperbilirubinemia.

The viral infection mumps and Kawasaki virus have been implicated in some sporadic cases of pancreatitis. But this is unusual and this patient doesn't have a history of it.

Intraductal stone formation is what causes pancreatitis in patients who have hypercalcemia due to hyperparathyroidism or some other conditions. They usually have additional features mentioned in the history that are associated with hypercalcemia. These may include constipation or kidney "stones, bones, groans, and moans."

Finally, fatty acid deposition with ensuing inflammation is the mechanism of pancreatitis in patients who have familial hyperlipidemia. They have those really high triglycerides. They would usually have other features mentioned like xanthelasma or early atherosclerosis or family history.

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21: Sequelae of Streptococcal Pharyngitis Jun 19, 2019

Show notes

Session 21

Today, we've got some interesting case of a 14-year-old male with some malaise and abdominal pain.

Once again, we're joined by Dr. Karen Shackelford of BoardVitals. Check out the resources they have to offer. Use the promo code BOARDROUNDS to save 15% off upon purchasing a QBank.

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This podcast is part of the Meded Media network where we help premeds and medical students as they journey towards becoming great physicians.

[02:15] Question of the Week

A 14-year-old male is evaluated for malaise and abdominal pain. He reports passing dark urine this morning. His past medical history is significant for Streptococcal pharyngitis ten days ago, for which he received Amoxicillin.

Today, his vital signs are within normal limits, except for an elevated blood pressure of 145/95 mmHg. Examination reveals spatial edema with pronounced periorbital swelling. He has 1+ pedal edema bilaterally. Abdominal exam reveals mild, diffuse tenderness without rebound or guarding.

Laboratory studies are unremarkable except for a serum creatinine of 2 mg/dL. What is the common finding associated with the patient's condition?

(A) Hypovolemia

(B) Polyuria

(D) Hypokalemia

[03:30] Thought Process Behind the Answers

The correct answer here is C. Basically, the patient has glomerulonephritis. This is characterized by red blood cell casts that are almost pathognomonic for glomerulonephritis.

Poststreptococcal glomerulonephritis is not common but also not unusual. The history of streptococcal pharyngitis should lead to that conclusion.

Other symptoms of glomerulonephritis include white blood cell casts, hematuria, and proteinuria. But for this question, you have to hone in on the glomerulonephritis.

Other findings in the urine sediment include granular casts. Dysmorphic red blood cells are strongly associated with glomerulonephritis and proteinuria. This is clinically manifested by a slow and progressive rise in serum creatinine and fluid hypertension, peripheral or periorbital edema, and sometimes, hypercoagulability.

Rhabdomyolysis may come to mind but it wasn't really an option among the choices. This could happen on the boards.

There might be systemic manifestations of some underlying disease process associated with glomerulonephritis. There's a group of immunologically triggered disorders that result primarily or characterized by glomerular inflammation. It can also manifest the proliferation of glomerular tissues that damage that basement membrane, mesangium, or the capillary endothelium.

[07:15] Understanding the Other Answer Choices

Glomerulonephritis is associated with hypervolemia. In this case, you have the proteinuria. But with the edema, you should immediately be able to figure out that it wasn't associated with hypovolemia. The patient had pedal edema and periorbital edema.

It is also important to mention that there are three primary mechanisms of glomerular inflammation. And what distinguishes a nephrotic syndrome from glomerulonephritis is the inflammation as a mechanism of damaging the glomerular apparatus.

This might come in the boards that the mechanisms are either immune complex deposition as in this case. Anti-glomerular basement disease is associated with Wegener's granulomatosis, eosinophilic granulomatosis with polyangiitis, or microscopic polyangiitis.

The other mechanism is the antineutrophil cytoplasmic autoantibody (ANCA) or small vessel vasculitis. It causes damage to the glomerular filtration barrier. This results in the leakage of plasma proteins and inflammatory cells into the renal tubule.

Patients may even have pulmonary edema in some cases. The hypertension results from retaining salt and water.

The patient has a rising creatinine and so hyperkalemia is more likely to happen. So this is an easy one to rule out.

Polyuria is associated with diabetes and causes diabetic ketoacidosis. This isn't that uncommon. Further laboratory testing is needed to determine the ideology. Typically on post-streptococcal glomerulonephritis, it is self-limited. A fair amount doesn't progress to renal failure.

But testing is needed to determine the ideology on other cases whether it's long-lasting or the significant decline in glomerular filtration rate. There is usually a raise in serum complement levels, anti-neutrophilic cytoplasmic autoantibodies, antiglomerular basement membrane autoantibodies, antinuclear antibodies, anti-double stranded DNA.

The treatment is just supported in these cases or treatment of the underlying disorder if there is one that you can determine from these other tests.

Links:

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BoardVitals

20: Fetal Stress Test: USMLE and COMLEX Prep Jun 12, 2019

Show notes

Session 20

Today, we tackle another maternal-fetal or pregnancy question.

We're joined once again by Dr. Karen Shackelford from BoardVitals. They offer a comprehensive QBank for Step 1 and Level 1. And even as you continue on your medical school journey, they have QBanks for Shelf exams as well. Use the promo code BOARDROUNDS to save 15% on your purchase. Or text BOARDROUNDS to 44222 and we'll send you the link and promo code.

[01:58] Question of the Week

A 39-year-old G1P0 presents at 37 weeks of gestation. She has not noticed any fetal movement for the past six hours. The fetal heart rate is 110 and a nonstress test was performed and it's nonreactive. Which of the following statements is correct?

(A) A fetal heart rate of 110 is abnormal.

(B) Fetal heart rate acceleration results from dopaminergic stimulation.

(D) Fetal head compression results in reflex flowing of the fetal heart rate.

(E) Usually, a nonstress test leads to a reduction in neurologic injury and fetal death.

[03:10] Thought Process

The correct answer here is correct C. The non-stress test should be reactive and a fetal heart rate of varies a bit. And around 110-160 is normal.

But the non-stress test is the most commonly used method. There's no evidence, however, that improves fetal outcomes in pregnancy. This is still initiated in women at about 26-28 weeks of gestation.

For fetal hypoxemia and high-risk pregnancies, the older patient is a high-risk pregnancy. It actually starts at the age of 34-35.

A reassuring test doesn't mean all is well. It only reassures fetal wellbeing in terms of oxygenation.

The fetus moving is characterized by two or more fetal heart rate accelerations. And they peak at least 15 beats per minute above the fetal baseline. This would last at least 15 seconds before returning to baseline. That's the over 20-minute interval.

A nonreactive nonstress test can reflect fetal hypoxemia or acidosis. It can also be caused by maternal smoking, fetal sleep, fetal immaturity, cardiac anomalies, and sepsis. If the mother is taking on the cardio-acting medication, it will result in changes in the fetal heart rate. But they don't necessarily indicate fetal problems.

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19: Appropriate Management of PPROM at 26 Weeks Gestation Jun 05, 2019

Show notes

Session 19

Today, we have Dr. Karen Shackelford from Bard Vitals, joining us as we break down another question.

Meanwhile, have a look at Meded Media for more resources available to premeds and medical student.

Another podcast medical students could listen to is Specialty Stories, where I talk to different physicians about their career and their specialty. They talk about why they chose it and what they like about it. Also, learn about what you as a medical student could be doing to make yourself more competitive for this specialty.

[01:40] Question of the Week:

A young woman is 26 weeks pregnant. She's 25 years old. Gravida 1 Para 0. 26 weeks gestation. She came into the emergency department complaining of leaking vaginal fluid for about three days, not huge, just some leaking.

She's had some intermittent contractions but they're fairly infrequent. A sterile speculum exam is performed. It revealed some pale, yellow, watery fluid in the vaginal valve. Her cervix is dilated 4 cm. The vaginal fluid is tested, has a pH of 7.1.

This is at an academic center where they still do the Fern test with arborization when the fluid is examined under a slide. An ultrasound is performed and it reveals oligohydramnios.

Which of the following measures is appropriate in the management of this patient? Her lab results and her pee is negative for Group B Strep.

(A) Ovarian section

(B) Flush immediate delivery

(D) Tocolysis

(E) Supplemental progesterone

[03:30] Thought Process

There is a premature rupture of membranes (PROM). If it were a placental abruption, we can take it to a C-section. But for PPROM (preterm PROM) before 37 weeks, you want to delay the delivery as long as you can. So the correct answer here is the antenatal steroid therapy to mature the lungs.

Most women who have PPROM deliver within a week. If it is within 7 days, you should initiate the steroid therapy.

The management of PPROM would depend on factors like the gestational age, the presence or absence of infection, presence or absence of labor, any sign of abruption. Fetal stability and heart monitoring should also be managed.

The American College of Obstetricians and Gynecologists (ACOG) recommends that women who have PPROM who are more than 34 weeks of gestation should deliver. But it doesn't need to be a C-section. Normal spontaneous or induced vaginal delivery is fine.

In women less than 34 weeks, the pregnancy should be managed expectantly just until fetal maturity development. As long as the fetus is stable, the fetus will benefit by prolonging time in the uterus.

Having the antenatal steroids will improve lung maturation. But you have to balance that with the benefits like expectant management against the risks associated with like a prolonged PPROM. Placental abruption is an increased risk as well as cord prolapse or cord compression.

[06:40] Looking at the Other Answer Choices

In the lab results, the patient had a negative Group B Strep test. Antibacterial prophylaxis for Group B Strep is indicated if somebody delivers within 48 hours in an unknown status or a positive test.

But you give these patients antibiotics as it prolongs the latency of the pregnancy. It's generally associated with better fetal results. It reduces respiratory distress syndrome and neonatal death. It reduces the risk of intraventricular hemorrhage, necrotizing enterocolitis, and all preemie problems.

It also reduces the duration of neonatal respiratory support needed. There's no increase in maternal or neonatal infection to balance that. ACOG recommends the corticosteroids that present between 24 and 34 weeks of gestation. And if you had an earlier pregnancy, you would give antibiotics in those cases.

So Group B Strep prophylaxis is indicated. ACOG would recommend erythromycin. Some doctors will prescribe Zithromax because it's easier to take. They also recommend IV ampicillin and oral amoxicillin. There are no data to support so it going to cover a large variety of vaginal pathogens. So the antibiotics would not be for Group B Strep but to prolong the pregnancy latency.

Tocolysis is inappropriate in this case because the patient is in active labor with cervix dilated to 4cm. With any woman who has more than 4cm of dilation or signs of chorioamnionitis or nonreassuring fetal stress test, these signs of abruption are the same thing.

The only setting for tocolysis to be indicated in this setting is to delay delivery again for 48 hours to allow the glucocorticosteroids to take effect. But this should never be given for more than 48 hours. So you're not going to delay delivery that long given that most women deliver within a week.

[10:00] BoardVitals

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18: Determining Causative Agent of a Severe and Painful Rash May 29, 2019

Show notes

Session 18

As always, I'm joined by Dr. Karen Shackelford from Board Vitals. If you haven't yet, check out Board Vitals and use the promo code BOARDROUNDS to save 15%. They have a huge database and question bank to help you get the practice you need to get the score that you need.

[01:35] Question of the Week

An older patient comes in with a painful rash. We have a 64-year-old female who presents complaining of a severe painful rash that is localized to the left side of her upper back and neck. She knows that the area of the rash feels hot and burning and extremely painful.

She is otherwise healthy with no significant past medical history. On exam, her vital signs were within normal limits. And her exam is significant, primarily, because she has a large, red vesicular rash running along her left shoulder in confluent patches. She remarks that the lesions were smaller a few days ago and they quickly start to bubble over into larger 02:39. The physician performed a Tzanck smear to confirm her suspicions.

She found the test to be positive for multinucleated giant cells. The patient will have which of the following characteristics?

(A) Gram-positive, catalase-positive, beta-hemolytic and arranged in clusters

(B) Branching pseudohyphae with budding yeast cells

(D) Enveloped-virus with positive-strand RNA virus

[04:30] Thought Process

The correct answer is C. Varicella zoster virus would probably come to mind as well as shingles as the Tzanck smear showed multinucleated giant cells – herpes simplex virus 1 and 2 (HSV 1 and 2) as well as pemphigus vulgaris. Other findings you would probably see on the Tzanck smear would include acantholytic cell and keratinocyte ballooning.

This test is not typically performed usually as a clinical diagnosis. But it can be performed in the office. The patient can be immunocompromised with atypical looking lesion or atypical presentation. So we'd think of herpes and varicella zoster.

For the other answer choices, Choice A is Staphylococcus aureus, which isn't a choice for a skin infection.

Choice B is a fungus. A fungal disease like Candida can cause a really nasty rash. But it won't be the vesicular nor the dermatomal, which this question suggests.

Varicella zoster virus is latent in the sensory ganglion so it tends to erupt on one or two contiguous dermatomes, although it can erupt outside of the dermatome. But it's not going to be a big eruption and just one or two vesicles scattered somewhere else from reactivation of the viral particles.

Option D is Rubella. It causes a rash and it's usually tested for IgM antibodies. If a test is needed, it's not the Tzanck smear.

[07:45] Possible Question Points About the Herpes Virus

About 30% of Americans will have it at some point in their lives coming from reactivation of the virus. It causes two clinically distinct diseases including chicken pox.

Chicken pox would be characterized by vesicular lesions but they're on different stages of development. They're concentrated on the face and the trunk. It's an airborne virus that invades the lymphoid tissue in the nose or nasopharynx.

The virus overcomes local host defenses. The epidermal cells usually react by making alpha-interferons. That's the incubation period.

When the virus can overcome the local host defenses, then you've got a viremia. Then the virus downregulates your immune response through a variety of mechanisms, such as the inhibition of the expression of interferon response genes.

When the virus remains latent for years in most cases, you're more at risk of reactivation as you get older because you have a diminished T-cell response.

This is the same reason that people with immuno-compromise are more likely to erupt with shingles. It's a unilateral vesicular eruption, usually in the dermatome.

The reactivated varicella can travel either way. It can travel peripherally through the sensory ganglion and go down the sensory nerve. This results in a skin infection or the characteristic rash.

It can also reactivate and move centrally from the ganglion. This is seen in those who are severely immuno-compromised. But this results in some of the complications associated with herpes zoster like meningitis-encephalitis.

Some of the syndromes include the Ramsay Hunt syndrome but it's a random thing. It occurs whenever the virus replicates in the geniculate ganglion. It travels down the 8th nerve and you have vesicles on the auricle or in the ear canal – ipsilateral facial paralysis.

Herpes 11:12 is a pretty significant complication. You have to recognize it really early on because it can cause blindness. You can get herpes keratitis and acute retinal nephrosis. The treatment is going to be an antiviral ganciclovir or acyclovir.

Postherpetic neuralgia is another big complication with severe significant pain (3 out of 10 and higher for about 90 days or more). Some people can have sensory changes. It can be intensely pruritic.

If you get vesicular lesions on the nose then the nerve distribution is pretty worrisome so you have to be aware of that.

[12:50] Board Vitals

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17: USMLE and COMLEX Prep: 10 y/o Pediatric Patient May 22, 2019

Show notes

Session 17

Dr. Karen Shackelford from BoardVitals is joining me once again for another round of discussion. This week, we tackle a certain kind of pediatric illness.

[01:11] Question of the Week:

A 10-year-old male patient is evaluated for abdominal pain he has had for two days. He has a rash on his buttocks and thighs. It appeared about three days ago.

He's also complaining of some pain in his ankles and knees. His past medical history is unremarkable. But he was seen in the clinic two weeks ago with symptoms of an upper respiratory infection.

On physical exam, his abdomen has standard palpation. 01:42 He has multiple palpable purpuras on his buttocks and upper thighs. 01:50 His ankle is swollen and tender on the right. There's no warrant for eczema. His knee is tender.

But otherwise, his exam was unremarkable. His laboratory study is showing a normal CBC. On urine 02:09, he has microhematuria.

What is the most likely diagnosis?

(A) IgA vasculitis (formerly Purpura)

(B) Hemolytic uremic syndrome

(D) Acute post-streptococcal glomerulonephritis

[03:40] Thought Process

The correct answer here is IgA vasculitis. The palpable purpura on the buttocks and lower extremities is one of the criteria you have to have for purpura, without thrombocytopenia.

The other symptoms this patient has, where you could have one or all of these other symptoms, including polyarthralgia, usually in the hip, ankle, and/or knee joints.

GI symptoms include abdominal pain, nausea, vomiting, 05:26 or intussusception. Thi has renal involvement, without thrombocytopenia or coagulopathy. These are the two big things.

As mentioned, the CBC was normal and he did have the proliferative glomerulonephritis, which occurs with the IgA deposition in the glomeruli.

Leukocytoclastic vasculitis is characterized by leukocytes. Neutrophils or monocytes are around the small vessels – the arterioles and venules. There's IgA deposition. There can be IgG or IgM. There is complement C through a deposition. This is what you would see in a biopsy.

The lesions are generally in the GI tract or in the skin (which are typically the ones that are biopsied). But if the patient does develop the glomerulonephritis, renal biopsy will show that. That doesn't develop in every case.

The disorder is self-limited so treatment-supportive. It's an immune complex seen usually after an upper respiratory infection.

In one case series, it has been associated with the MMR vaccine, although this might not have been held up in the later studies.

This is also common between the ages of 3 and 11. One of the diagnostic criteria is that the patient has to be under 20.

[07:35] Going Through Other Answer Choices

In hemolytic uremic syndrome, you can have 07:41 purpura, although they're non-palpable and they're palpable in an 07:49 purpura. That occurs in hemolytic uremic syndrome due to thrombocytopenia. And this patient has a normal CBC.

Hemolytic uremic syndrome is usually associated with E.coli infection in the previous case of diarrhea. But there's no history of that in the patient.

There is abdominal pain but the rash is not limited to the lower extremities and buttocks. That is characteristic of HSP IgA vasculitis.

Kawasaki disease usually occurs in children under the age of 4. The case will usually present a child of Asian descent. It's more prevalent in Japanese children who are at a high risk of IVIG resistance.

They will generally have conjunctivitis and fever for more than 5 days. They have that strawberry tongue. The skin manifestations are non-palpable purpura, but there are periungual desquamation and hand-and-foot erythema.

Acute post-streptococcal glomerulonephritis can present with hematuria. It can occur after a skin infection or a pharyngeal infection. That was meant to be with a rash. Maybe someone will consider this because there's a rash involved.

As group-A beta-hemolytic strep, this patient had a previous upper respiratory infection which could potentially have been caused by strep. But arthralgia isn't common. Abdominal pain isn't common. And the purpura also not associated with acute post-streptococcal glomerulonephritis.

[11:10] BoardVitals

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16: USMLE and COMLEX Prep: 26 y/o Pregnant Immigrant May 15, 2019

Show notes

Session 16

We're joined once again by Dr. Karen Shackelford from BoardVitals. This week, we discuss a case about an immigrant from Central America who's pregnant.

[01:30] Question of the Week:

A 26-year-old, G1P0 female is a recent immigrant from Central America and she presents with crampy abdominal pain and vaginal bleeding. By her dates, because she hasn't received prenatal care. She's of 25 weeks gestation and her past medical history is unremarkable.

She takes an over-the-counter multivitamin but no other medication. She denies alcohol, tobacco, or illicit drug use. And she spontaneously delivers a stillborn fetus.

The fetus is noted to have microcephaly and imaging performed reveals thinning of the cerebral cortices, ventriculomegaly, and subcortical calcifications.

Viral RNA is identified in both maternal and fetal body fluids. The virus is a neurotropic virus that disrupts proliferation migration and differentiation of neural precursor cells in the developing fetus.

Which of the following is the most likely pathogen?

(A) Herpex simplex virus

(B) Rubella

(D) Cytomegalovirus (CMV)

[03:50] Thought Process

The pathogen here is Zeka virus. CMV is a pretty good distraction here since the question mentioned ventricular calcification. But with respect to being a neurotropic virus, Zeka is and has been in the news a lot.

It's a single-stranded RNA virus transmitted by mosquitoes. It's also related to dengue virus and the yellow fever virus.

The infection results in clinical manifestations in about 20% of people and the rest would not know they've had it. If you're infected, you're symptomatic. You have a low-grade temp. You can develop a maculopapular rash, arthralgia, and conjunctivitis.

There are other neurologic complications besides the general microcephaly. You can end up with Guillain-Barre, myelitis, meningoencephalitis, seizures, and congenital spasticity which the mother has vertically transmitted during delivery or it can be transmitted through the placenta.

It can also be sexually transmitted and through other body fluids. It can also be caused by laboratory exposure such as the transplant of infected organs. It's fairly infectious.

[05:42] Pregnant Women Should Avoid Infested Areas

Pregnant women in the United States have been advised across the board to avoid travel in regions where mosquito transmission of Zeka occurs if they're going to be less than 6500 feet in altitude. This is the same thing with malaria in some parts of Kenya.

[06:12] Understanding the Other Viruses

CMV is a double-stranded DNA virus. The question mentioned specifically that the virus was an RNA virus. So this would be one reason you would disqualify CMV from your correct answers.

But general CMV infection can result in chorioretinitis, hearing loss, jaundice, and periventricular calcification on imaging studies.

CMV is not associated with tropical travel or immigration.

Rubella is a single-stranded RNA virus. Congenital exposure is primarily associated with hearing loss, cataracts and congenital cardiac defects instead of neurological defects.

HSV is a double-stranded DNA virus. Congenital exposure is associated with skin lesions and obstruction of brain tissue. The candidate here can rule out HSV for no other reason than it's a DNA virus.

[07:55] Expand Your Knowledge and Be Up-to-Date

Zeka has been in the news a lot lately. And content gets updated on USMLE. So you should be aware of these things even if you just hear about them once or twice while you're studying. You're more likely to diagnose it than if you don't remember hearing about it at all during your studies.

"You have to be aware of what is potentially out there because you can't diagnose something you don't think of."

[08:40] BoardVitals

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You board exam score is vital for you to be able to match into your specialty of choice. So there is no such thing as being over prepared for your board exams. Start now. Sign up for a 6-month plan or a 3-month plan. Get started early. Get through the content because the more questions you do, the better you do on your board exams.

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15: USMLE and COMLEX Prep: Tropical Medicine—Dengue Fever May 08, 2019

Show notes

Session 15

This week, we're joined by Dr. Karen Shackelford from BoardVitals.

If you're looking for more prep with your USMLE Step 1 or COMLEX Level 1 training, visit BoardVitals and check out their QBanks for Step 1 and Level 1.

Sign up for either 3 months, 6 months, or even 1 month. Your signup will have a vaccine donated through the #GiveVax program. If you sign up for the 3 months and 6 months, you'll get access to Ask a Clinician, where you can connect with the BoardVitals medical experts to answer your content questions.

Use the promo code BOARDROUNDS to save 15% off of your purchase.

[02:17] About Dr. Karen Shackelford

Karen is a former ER clinician. She did her residency in medical school at the University of Mississippi. She eventually moved to Pennsylvania and began working remotely with BoardVitals as a contributor and editor.

[03:20] Question of the Week

A 35-year-old female patient returned 10 days ago from a mission trip to Nigeria. He was evaluated in the clinic a week ago, complaining of a high fever. She had a rash on the axilla, face, and extremities.

The symptoms she had experienced were similar to some she had two years earlier after returning from the same mission trip. Those symptoms resolved with only symptomatic treatment.

Today, her husband took her to the emergency department reporting that her fever had resolved two days ago. But she began to complain about abdominal pain and then she appeared very lethargic.

On exam, her skin is cool and blocky. She had circumoral sinuses. Her pulse is weak and rapid. And her blood pressure is 80/60 mm Hg. She has a diffused confluent rash and her liver 2 cm below the costal margin.

Laboratory studies are significant for a platelet count of 70,000 cells/mL. White blood cell count is 2,000 cells/mL with predominant lymphocytosis. Her serum aminotransferase is elevated.

Which of the following is most likely caused by these severe symptoms?

(A) Has bacterial super infection

(B) Inoculation with a larger viral load

(D) Different viral serotype change

[05:08] Thought Process Behind the Answer

Antigenic drift is characterized by small changes in the viral structure. It denotes spontaneous changes in the viral type. This is how viruses avoid getting destroyed by vaccines.

Serotype is defined as a serologically different strain of microorganism with slight structural differences. They're classified together and have the same type of immune response. But just with a slight variation in their effect on the immune system.

The correct answer here is D.

The patient, in this case, is her second infection with Dengue Virus but with a different serotype. There are four serotypes of that virus. It's not atypical for somebody to have a mild case that resolves or even asymptomatic initial infection.

At that time, the virus presents to a naive immune system. The second time around, it triggers a more significant immune response instead of immunity because of the antigenic differences that the virus responds to.

A lot of these viruses are becoming more common in areas that people routinely travel to. A severe viral infection can resolve in hemorrhagic fever and epistaxis, hepatomegaly, circulatory shock.

And it resolves through increased capillary permeability because the immune system is having a fluoric response to this second exposure to a slightly different serotype.

[10:05] Third Infection

If she had a third infection with Dengue Virus, it could be another viral serotype which can be potentially harmful. Although you might have some measure of immunity against the same one.

When somebody comes into the office in the Emergency Department with a history of travel to the tropics and they have fibromyalgia, lethargy, and a rash, there are several things that could be wrong with them.

Check on Chikungunya fever or dengue fever. They should be considered. But the one that is potentially fatal is dengue. The person could seem to recover. The fever could resolve. They could also become progressively ill and have circulatory collapse several days later. Hence, they should be monitored closely after an episode.

The tests for these two are not readily available in those hospitals. So close monitoring should be done if they're coming with acute high fibromyalgia, lethargy, and rash after a trip to the tropics.

[11:50] Potential Questions

Both fevers are viral and both transmitted by the Aedes mosquito. There's not a vaccine and not a specific treatment. It's just supported. In most cases, the initial infection is asymptomatic or mild asymptomatic.

Increased formation in immune complex so she has a pretty flourid response to dengue fever would be the primary mechanism behind it. Again, no specific treatment.

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14: USMLE and COMLEX Prep: Psychiatry—Coping Mechanisms Apr 24, 2019

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Our psychiatry question is asking us to identify the description of behavior for our 38 y/o male patient. Follow along to test your knowledge of psychiatry!

13: USMLE and COMLEX Prep: Mechanism of Injury for Foot Weakness Apr 17, 2019

Show notes

Session 13

We have a great musculoskeletal question for today. As always, we're joined by Dr. Andrea Paul from Board Vitals.

[01:30] Question

A 27-year-old male is undergoing evaluation for left foot weakness. On his exam, he's unable to curl his toes. He has one of five strength with plantar foot flexion and five out of five with dorsiflexion. His foot is everted at rest and he has decreased sensation on the sole of his foot.

What was the most likely mechanism of his injury?

(A) Fibular neck fracture

(B) Hip dislocation

(D) Knee trauma

(E) Pelvic fracture

[03:45] Thought Process

If you have a fibular neck fracture, this will injure your perennial nerve where you will have lots of dorsiflexion and the sensation on the dorsum of the foot. So choice A is out

L3 is too high up as well. This involves the sciatic nerve. The patient would have felt a neuropathic pain down the back of the leg.

Hip dislocation is unlikely because the patient is a 27-year-old. This is pretty uncommon. But if he did, then that would have affected the gluteal nerve. This would make it difficult for him to stand up or extending his hip.

Pelvic fracture would be more of the femoral nerve, affecting hip flexion and extension.

The knee trauma is the right answer here, If they had said posterior knee trauma, this would have made the exam a little easier. Specifically, this is a tibial nerve injury. It typically runs right down the middle of the back of the popliteal fossa.

So any knee injury is going to affect the nerves and vessels that run through there. When you have an injury in the tibial nerve, the commonplace for pain is the back of the knee. This is a common sports injury, although other things can cause this too. One example is when you're wearing shoelaces being tied around the calf. Casks can cause this as well as ankle fractures.

[08:47] Tibial Nerve Affecting the Knees and Ankle

It's asking what's "most likely" so just keep that in mind. And typically, this is a very common injury known as the tibial tunnel syndrome. It most commonly occurs at the back of the knee. The tibial nerve passes right behind the medial malleus before it goes around the foot so the ankle area would be affected here too.

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