Property:Explanation
Jump to navigation
Jump to search
This is a property of type Text.
W
The episodes described in the question are most likely associated with a panic attack. Panic attacks and palpitations accompanied by a mid-systolic click suggest mitral valve prolapse as the diagnosis in this patient. Mitral valve prolapse is mostly asymptomatic but sometimes presents with atypical chest pain, palpitations and panic attacks. Squatting and handgrip which increase left ventricular chamber size diminish the murmur of mitral valve prolapse. Conversely, valsalva maneuver or standing decrease venous return and thereby worsen the murmur. Beta blockers are the preferred initial treatment in a symptomatic patient with mitral valve prolapse.
'''Educational Objective:''' Symptomatic mitral valve prolapse presents with panic attacks, palpitations and atypical chest pain. Beta blockers are the mainstay of initial treatment.
'''References:''' Page 91, 92 Master the boards step 2 CK second edition.<br/>
'''Educational Objective:''' <br/>
'''References:''' +
This patient describes episodes of dyspnea on exertion, pedal edema and dysphagia. Dyspnea and pedal edema with S4 gallop and a low ejection fraction on echocardiogram indicates heart failure or cardiomyopathy. This patient’s dysphagia and history of migration from a South American country like Brazil should raise suspicion for Chaga’s disease. Chaga’s disease causes dilation of the heart chambers and the esophagus, which causes dilated cardiomyopathy and dysphagia respectively. Chagas disease is caused by a protozoan Trypanosoma Cruzi and transmitted by reduvid bug (kissing bug).
'''Educational Objective:''' Chagas disease characterized by dilated cardiomyopathy , mega esophagus and is most common in South American countries such as Brazil, Cuba, Mexico etc. It is caused by a protozoan Trypanosoma Cruzi and transmitted by Reduvid bug (kissing bug).
'''References:''' Page 93, 94 Master the boards step 2 CK second edition, http://www.wikidoc.org/index.php/Chagas_disease_overview C.MichaelGibson,M.S.,M.D, http://en.wikipedia.org/wiki/Chagas_disease<br/>
'''Educational Objective:''' <br/>
'''References:''' +
History of sore throat, fever and gastrointestinal upset with symptoms suggesting heart failure now might suggest an infection leading to heart failure eventually. Many virus, bacteria, protozoa, fungi and parasites can cause myocarditis or inflammatory cardiomyopathy. Angiotensin receptor blockers, angiotensin converting enzyme inhibitors, potassium sparing diuretics and beta blockers improve mortality in cardiomyopathy, similar to their effect in heart failure.
'''Educational Objective:''' Angiotensin receptor blockers, angiotensin converting enzyme inhibitors, potassium sparing diuretics and beta blockers improve mortality in cardiomyopathy.
'''References:''' http://www.wikidoc.org/index.php/Coxsackie_B_virus C. Michael Gibson, M.S., M.D ,Page 93 Master the boards step 2 CK second edition.<br/>
'''Educational Objective:''' <br/>
'''References:''' +
A 38-year-old female with a facial rash, joint pain and chest pain that changes with position suggests connective tissue disease induced pericarditis. The most common connective tissue disease causing pericarditis is Systemic lupus erythematosus (SLE). Electrocardiogram findings of diffuse ST segment elevation also points towards pericarditis. The most specific test to diagnose Systemic lupus erythematosus is Anti ds-DNA antibodies.
'''Educational Objective:''' Anti ds-DNA is the most specific test for Systemic lupus erythematosus. Systemic lupus erythematosus is the most common connective tissue disease cause of Pericarditis.
'''References:''' Page 183 Master the boards Step 2 CK second edition<br/>
'''Educational Objective:''' <br/>
'''References:''' +
A 50–year-old male with a history of diabetes, hypertension and smoking who suffers from leg pain on walking (Claudication) suggests peripheral arterial disease (PAD).Peripheral arterial disease occurs due to blockage of blood supply to any peripheral body parts but mostly involves lower limbs. Smoking is one of the major risk factors for peripheral arterial disease. Physical examination of the involved limb may show loss of hair, loss of sweat. The best initial test for diagnosing peripheral arterial disease is ankle brachial index, the ratio of blood pressure measured in the ankles and brachial arteries. Ankle brachial index value <0.9 indicates peripheral arterial disease. Treatment of PAD should include aspirin, cilostazol and smoking cessation.
'''Educational Objective:''' Ankle brachial index is the best initial test in diagnosing peripheral arterial disease
'''References:''' Page 102 Master the boards Step 2 CK 2nd edition, Page 71 Master the boards step 3, 2009 edition.<br/>
'''Educational Objective:''' <br/>
'''References:''' +
50 year old male with a family history of ischemic heart disease with sedentary life style and a history of hypertension complaining of chest pain mostly points towards heart related chest pain as he has some risk factors. Even though the question states pain is related to food intake he definitely needs an electrocardiogram first to rule out ischemic heart disease. If the electrocardiogram shows no abnormality we might want to think about gastrointestinal related pain and prescribe pantoprazole and see how he responds. But in this case always rule out ischemic heart disease first by opting for electrocardiogram.
'''Educational Objective:''' The initial test in case of chest pain depends on patient’s age and the presence of risk factors for heart disease. In this case initial test of choice must be electrocardiogram to rule out heart disease.
'''References:''' Page 42 Master the boards Step 3 2009<br/>
'''Educational Objective:''' <br/>
'''References:''' +
The type of pain with sudden onset and characteristic radiation to the back between the scapulae with high blood pressure in a hypertensive patient with smoking history hints strongly towards Aortic dissection. The most important initial task is to reduce the arterial blood pressure which could worsen the tear in the aorta. During aortic dissection, a false lumen is created, often by mechanical stress or compromised integrity of the arterial wall, as in Marfan’s syndrome. Beta blockers are always the initial drug of choice to reduce the force causing the tear in the aorta.
'''Educational Objective:''' Beta blockers are the initial drug of choice in aortic dissection to decrease the tearing force in the aorta and thus prevent further dissection of the aorta.
'''References:''' Page 70 master the boards Step 3 2009, Page 104 Master the boards Step 2 CK second edition<br/>
'''Educational Objective:''' <br/>
'''References:''' +
The patient in this vignette is suffering from pericardial tamponade. Electical alternans is defined by an electrocardiogram with QRS complexes of varying heights, a common feature of pericardial tamponade. Tachycardia, hypotension, pulsus paradoxus and jugular venous distension in this case are also characteristic of pericardial tamponade. In this case, a stab wound has caused ventricular rupture and rapid collection of blood in the pericardium. As little as 100mL of fluid can cause tamponade in the case of rapid accumulation, such as trauma or ventricular rupture. Pulsus paradoxus is a drop in the blood pressure more than 10 mm of hg on inspiration. Pericardial tamponade is also referred to as cardiac tamponade.
'''Educational Objective:''' Electrical alternans is characterized by varying heights of QRS complexes on electrocardiogram and is a characteristic finding in pericardial tamponade.
'''References:''' page 64, 99,100, 384 Master the boards step 2 CK second edition, Page 69 Master the boards Step 3 2009<br/>
'''Educational Objective:''' <br/>
'''References:''' +
The patient in this vignette presents with syncope and a heart murmur characteristic of aortic stenosis. Electrocardiogram and X-ray with left ventricular hypertrophy are also findings of consistent with aortic stenosis. Aortis stenosis in old aged patients is due to calcification of the aortic valve due to age with a mean age of 65-70 years old. Aortic stenosis can present in younger patients (40s to 50s) due to calcification of a congenital bicuspid aortic valve. The definitive treatment for this condition is valve replacement.
'''Educational Objective:''' Valvular replacement is the definitive treatment in aortic stenosis. Bioprosthetic or mechanical valves can be used.
'''References:''' Page 63,64,65 Master the boards step 3 2009, Page 89 Master the boards step 2 CK second edition<br/>
'''Educational Objective:''' <br/>
'''References:''' +
Irregularly irregular 170 pulse rate and the electrocardiogram findings suggest atrial fibrillation in this patient. Hyperthyroidism may be suspected as an underlying cause based on her history of heat intolerance, irregular menstrual cycles and weight loss. The patient has experienced tachycardia for 3 days so the treatment of choice will be a rate controlling drug such as a beta blocker.
'''Educational Objective:''' Atrial fibrillation in hemodynamically stable patient is managed with rate controlling medication such as beta blockers.
'''References:'''Page 72 Master the boards step 3 2009, Page 554 Master the boards step 2 CK second edition<br/>
'''Educational Objective:''' <br/>
'''References:''' +
The murmur of mitral stenosis increases in intensity on squatting as the venous return increases and the blood flow through the valve increases. It also increases on leg rising for the same reason. Mitral stenosis is most often caused by rheumatic fever. Pregnancy can precipitate symptoms of mitral stenosis in otherwise asymptomatic patients.
'''Educational objective:''' The murmur of mitral stenosis increases on Squatting and leg rising.
'''References:''' Page 59, 65 Master the boards Step 3 2009, Page 86, 87, 88 Master the boards step 2 CK second edition<br/>
'''Educational Objective:''' <br/>
'''References:''' +
The image shown above is that of ''Staphylococcus aureus''. ''S. aureus'' is a gram-positive (violet color on gram-stain) coccus (circular shape) organized in clusters that resemble grapes. In fact, the Greek word "staphyle" means "grape". ''Staphylococcus aureus'' classically colonizes the skin transiently and anterior nares more persistently. In approximately 30% of individuals, ''S. aureus'' can be found in the anterior nares with absolutely no symptoms. Other sites of ''S. aureus'' colonization are also possible, such as in the throat. Nasal carriage of ''S. aureus'' has become a way of spread of multiresistant staphylococci, such as methicillin-resistant ''S. aureus'' (MRSA). S. aureus is rather virulent due to several factors including its polysaccharide capsule, surface adhesins, exotoxins (hemolysins, superantigens, & Panton-Valentine toxin), as well as the ability to form biofilms most often detected in ''S. aureus'' species that are able to persist in the anterior nares and colonize mucosal surfaces.<br/>
'''Educational Objective:''' ''Staphylococcus aureus'' are gram-positive cocci that are arranged in clusters. The classical site of primary colonization is the anterior nares.<br/>
'''References:''' Hu L, Umeda A, Kondo S, et al. Typing of Staphylococcus aureus colonising human nasal carriers by pulsed-field gel electrophoresis. J Med Microbiol. 1995; 42(2):127-32.<br>
Bennett JE, Dolin R, Blaser MJ. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. Elsevier Health Sciences; 2014.<br>
Image attribution: Bobjgalindo. 2005. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 license. +
Transport of membrane-bound organelles (MBO) along the microtubules requires special proteins that can move organelles, like vesicles, from the positive pole of the microtubule to its negative pole and vice versa. Early experiments that studied the movement of vesicles showed that organelle transport requires not only ATP as a source of energy but also transport proteins, such as kinesin and dynein. Kinesin is capable of transporting organelles from the negative to positive pole of the microtubule; whereas dynein is capable of transporting organelles from the positive to negative pole. As organelles were initially purified and salt-washed, the transport proteins were lost, and despite an ATP rich microenvironment, no movement occurred. Addition of axoplasmic supernatant that contained the transport proteins led to eventual organelle transport along the microtubule.<br/>
'''Educational Objective:''' Kinesin helps transport organelles from the (-) to (+) pole of microtubules.<br/>
'''References:''' Schroer TA, Schnapp BJ, Reese TS, et al. The role of kinesin and other soluble factors in organelle movement along microtubules. J Cell Biol. 1988; 107:1785-1792. +
Influenza virus is an enveloped virus that contains 3 major proteins: Hemagglutinin (HA), neuromanidase (NA), and M2 that are present on its lipid bilayer membrane. Protein matrix under the lipid bilayer membrane is made of M1 protein. Viral entry into the cells starts with viral internalization by receptor-mediated endocytosis. Viruses are then trafficked along the endocytic pathway to endosomes. Viral factors, such as HA and NA are needed for the attachment of the virus to the cell and subsequent entry. At the same time, host factors, such as clathrin, are needed for the endocytosis. Clathrin is a protein that is important for the formation of vesicles needed for endocytosis. Clathrin is a large protein with light and heavy chains that forms "clathrin-coated vesicles" (CCV). It is able to transport proteins inside the cells between organelles to their target destination.<br/>
'''Educational Objective:''' Clathrin-mediated endocytosis is required by some viruses, such as influenza virus, for cell entry.<br/>
'''References:''' Lakadamyali M, Rust M, Zhuang X. Endocytosis of influenza virus. Microbes Infect. 2004; 6(10):929-936. +
Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria or mycobacteria. It can be usefully subclassifed on the basis of the causative organism, the route, duration and anatomic location of the infection. It usually present with fever, chills, erythema, and swelling over the involved bone.<br/>
'''Educational Objective:''' <br/>
'''References:''' +
Osteomyelitis is an infection of bone or bone marrow, usually caused by pyogenic bacteria or mycobacteria. It can be usefully subclassifed on the basis of the causative organism, the route, duration and anatomic location of the infection . It usually present with fever, chills, erythema, and swelling over the involved bone.
Diagnosis of osteomyelitis is often based on radiologic results showing a lytic center with a ring of sclerosis, though bone cultures are normally required to identify the specific pathogen. Conventional radiographic evaluation of acute osteomyelitis is insufficient because bone changes are not evident for 14–21 days after the onset of infection.
C.T and MRI is the best way to non- invasively approach the diagnosis of Osteomyelitis. MRI gives more details of the soft tissue involvement as a complication of Osteomyelitis (e.g. abscess or gas formation).
A three phase technetium bone scan is the diagnostic test of choice for suspected Osteomyelitis if the radiological results are negative.<br/>
'''Educational Objective:''' <br/>
'''References:''' +
Bloodstream-sourced osteomyelitis is seen most frequently in children, and nearly 90% of cases are caused by Staphylococcus aureus. In infants, S. aureus, Group B streptococci, and Escherichia coli are commonly isolated; in children from 1 to 16 years of age, S. aureus, Streptococcus pyogenes, and Haemophilus influenzae are common. In some subpopulations, including intravenous drug users and splenectomized patients, Gram-negative bacteria, including enteric bacteria, are significant pathogens
<table border="1" cellspacing="0" cellpadding="0">
<tr>
<td valign="top" bgcolor="#cccccc"><p>'''Infants (< 1 year)'''</p></td>
<td valign="top" bgcolor="#cccccc"><p>'''Children (1 to 16 years)'''</p></td>
<td valign="top" bgcolor="#cccccc"><p>'''Adults (> 16 years)'''</p></td>
</tr>
<tr>
<td valign="top"><p>Group B streptococci</p></td>
<td valign="top"><p>S. aureus</p></td>
<td valign="top"><p>Staphylococcus epidermidis</p></td>
</tr>
<tr>
<td valign="top"><p>Staphylococcus aureus</p></td>
<td valign="top"><p>Streptococcus pyogenes</p></td>
<td valign="top"><p>S. aureus</p></td>
</tr>
<tr>
<td valign="top"><p>Escherichia coli</p></td>
<td valign="top"><p>Haemophilus influenzae</p></td>
<td valign="top"><p>Pseudomonas aeruginosa</p></td>
</tr>
<tr>
<td valign="top"><p>-</p></td>
<td valign="top"><p>-</p></td>
<td valign="top"><p>Serratia marcescens</p></td>
</tr>
<tr>
<td valign="top"><p>-</p></td>
<td valign="top"><p>-</p></td>
<td valign="top"><p>E. coli</p></td>
</tr>
</table>
http://www.aafp.org/afp/2001/0615/p2413.html<br/>
'''Educational Objective:''' <br/>
'''References:''' +
It is very difficult to distinguish the flu from other viral or bacterial causes of respiratory illnesses on the basis of symptoms alone. Influenza viral infection usually present with fever, headache, cough, sore throat, arthralgia, and myalgia. The best diagnostic test for influenza is viral antigen detection testing of the nasopharyngeal swab.<br/>
'''Educational Objective:''' The best diagnostic test for influenza is viral antigen detection testing of the nasopharyngeal swab.<br/>
'''References:''' None. +
The adamantane drugs (amantadine and rimantadine) are approved for influenza A only, while the neuraminidase inhibitor drugs (zanamivir and oseltamivir) are approved for both influenza A and influenza B, and the recommended to be used when Influenza is the diagnosis if the patient presents within the first 48 hours after the onset of symptoms. In the United States, FDA-approved drugs against influenza are: amantadine, rimantadine, zanamivir (Relenza®), and oseltamivir (Tamiflu®).<br/>
'''Educational Objective:''' <br/>
'''References:''' +
Genital herpes is a common STD, and most people with genital herpes infection do not know they have it. Patient can get genital herpes even if the partner shows no signs of the infection. When there are clear vesicular lesions, there is no need to do a specific diagnostic test for herpes. The best treatment in genital herpes is acyclovir, valacyclovir, or famciclovir for 7-10 days. There is no cure for herpes, but treatment is available to reduce symptoms and decrease the risk of transmission to a partner.<br/>
'''Educational Objective:''' <br/>
'''References:''' +