ECG 07 : Thirty-one year old gentleman who recently underwent a right upper lung wedge resection for a necrotic granuloma
ECG 04 : Fifty-four year old woman with a history of metastatic malignant melanoma who is being evaluated for a subsequent course of chemotherapy.
USMLE step 1 : Q 35-37 :Answers
Question Number 35
Correct Answer: B
Explanation:
Chronologic Bias arises in this study since the author is comparing early and delayed repair of Ebstein's anomaly and assigned infants with such anomalies to either early childhood or adult repairs but is ignoring the fact that surgical facilities and resources would have changed substantially in twenty years. The concurrent comparison of control and experimentally treated patients is essential for avoiding chronologic bias. Chronologic bias can occur because diagnostic and therapeutic abilities change over time, and comparisons between control and intervention groups who are treated at different times, perhaps years apart, may reflect differences in an aspect of care other than the effect of the intervention itself. By the time delayed-treatment patients reached adulthood, the differences in outcome of repair might have as much to do with the differences in the diagnostic and surgical techniques of the two time periods as it would with the timing of the operation in the life of the patient.
Question Number 36
Correct Answer: B
Explanation:
At two months of age a child no longer clenches its fist tightly. It is able to follows object past the midline. The child smiles socially (after being stroked or talked to) and recognizes its parent. The palmer grasp usually disappears at two months. The Moro's (startle) reflex usually disappears when the child is between three to six months of age.
Question Number 37
Correct Answer: B
Explanation:
A three year old can alternate feet when going up steps and learns to pedal a tricycle. She copies a circle, undresses completely and dresses partially and dries hands if reminded. The child typically uses a minimum of 250 words, can use 3-word sentences; uses plurals, past tense; knows all pronouns and understands the concept of 2. The child can also group play, shares toys, takes turns, plays well with others and knows her full name, age and sex. During years three to five a child's vocabulary rapidly increases. A child of this age can distinguish fantasy from reality. The child typically takes risks even though punishment may result from its actions. Imaginary friends are very common at this age
8:55 AM 0
USMLE step 1 : Q 32-34 :Answers
Question Number 32
Correct Answer: A
Explanation:
Recall bias is especially important when the investigator has to rely on patient recollection to establish risk factors. The authors used in this study are relying on recalled age of menstruation. An eighty year old is much less likely to accurately remember the age of her first menstruation than a thirty year old. It is also well known that people with a disease are likely to recall an exposure to a risk factor differently than someone without it and that knowledge of the purpose of the investigation may lead the patient. This is another example of recall bias.
Question Number 33
Correct Answer: C
Explanation:
This study demonstrates overestimation of survival duration among screen-detected cases (relative to those detected by signs and symptoms) when survival is measured from diagnosis. This is an example of Lead-time bias The apparent effects of early diagnosis and intervention (measured in terms of how screening-detected cases compare with cases detected by signs and symptoms) are always more favorable than the real effects (measured in terms of how a population that is screened compares with a population that is not). The comparison between screening-detected cases and others overestimates benefit because the former consists of cases that were diagnosed earlier, progress more slowly, and may never become clinically relevant. This comparison, therefore, is said to be biased. In the figure below (representing one patient), the patient survives for 10 years after clinical diagnosis and survives for 15 years after the screening-detected diagnosis. However, this simply reflects earlier diagnosis because the overall survival time of the patient is unchanged.
Question Number 34
Correct Answer: D
Explanation:
Journals tend to accept articles which show something which would be of interest to their readership. They want to be the first journal to report something new. Publication bias is another concern that is particularly germane to the meta-analytic process. It occurs when study results are differentially reported, depending on the direction and strength of their findings. Publication bias is not an uncommon phenomenon, and it appears that the failure to publish the results of a particular study actually lies more with the investigator than with the editor. Investigators acknowledge that they are less likely to pursue publication when they have obtained uninteresting results. Moreover, authors can also impose publication bias if they selectively exclude data from a publication based on the nature of the findings. Methods have been devised to estimate the size of the problem in a given analysis
6:56 PM 0
USMLE step 1 :: Q 29-31 :Answers
Question Number 29
Correct Answer: D
Explanation:
The history is strongly suggestive of posterior urethral valves . The neonates who are not recognized at birth most commonly present within a few weeks with urosepsis, dehydration, and electrolyte abnormalities In the male neonate, posterior urethral valves are suspected when there is a palpably distended bladder and the urinary stream is weak. If the obstruction is severe and goes unrecognized during the neonatal period, infants may present later in life with failure to thrive due to uremia or sepsis caused by infection in the obstructed urinary tract. With lesser degrees of obstruction, children present later in life with difficulty in achieving diurnal urinary continence or with UTI. The diagnosis is established by voiding cystourethrography or perineal ultrasonography.
Question Number 30
Correct Answer: C
Explanation:
In sickle cell disease the hypoxemic and hypertonic environment of the renal medulla encourages sickling of red blood cells circulating through this region. This leads to the development of papillary infarction. A defect in urinary concentration resulting in a tendency toward volume depletion is one of the best-characterised abnormalities in sickle cell nephropathy. Obliteration of the vasa recta compromises the operation of the medullary countercurrent system and impairs the ability to generate and maintain medullary solute gradients. The concentrating defect may also be seen in the sickle trait. A defect in urinary acidification is common and manifested as distal renal tubular acidosis with hyperkalemia and hyperchloremic metabolic acidosis (type 4 renal tubular acidosis). The acidification defect is not usually observed in patients with sickle trait. Painless gross hematuria has been estimated to occur in up to 50% of patients with sickle cell nephropathy. It also occurs in patients with Hb SA or Hb SC. Eecurrent papillary infarction leads to papillary necrosis. Sickle cell crisis, dehydration, hypoxemia, and the use of non-steroidal anti-inflammatory drugs all predispose to papillary necrosis. Renal papillary necrosis is often silent, but it may progress to chronic renal insufficiency and predispose the patient to repeated urinary tract infections.
Question Number 31
Correct Answer: E
Explanation:
This study shows selection bias. Selecting a population of working population is selective since working people are healthy enough to work and therefore less likely to suffer from stroke. By definition a selection bias produces a subject pool that is not representative of the generalised population
6:41 AM 0
USMLE step 1 : Q 26-28 : Answers
Question Number 26
Correct Answer: A
Explanation:
A urethral stricture occurs when scar tissue forms in the urethra. The stricture blocks the urethra and may cause the urinary stream to slow to the point where the patient cannot urinate. Causes for urethral stricture formation include trauma ( sharp blow to the base of the penis), gonorrhea, or previous instrumentation of the urinary tract On questioning, the patient stated that he underwent cystoscopy 2 months previously. . Gonococcal strictures are the commonest cause of infective urethral strictures but rarely cause fistulas. Fistulas are typically secondary to TB infection and may be multiple. The genital involvement in Behcet's syndrome are ulceration of the labia or scrotum
Question Number 27
Correct Answer: A
Explanation:
Individuals with urinary lithiasis rarely can find comfort in any position. They sit, stand, pace, recline, and move continuously in an attempt to shake off whatever it is that is creating discomfort. Fever is not present unless urinary infection occurs along with the calculus. Pulse rate and blood pressure may be elevated because of pain and agitation. Examination of the abdomen reveals moderate deep tenderness on palpation over the location of the calculus and the area of the loin. Urinalysis in most patients with urinary lithiasis reveals the presence of microscopic or gross hematuria.
Question Number 28
Correct Answer: B
Explanation:
Hematuria and irritative bladder symptoms, such as dysuria or urinary frequency, are the most common presenting symptoms of bladder cancer. Most patients have hematuria, which is frequently gross but occasionally microscopic. The hematuria can be episodic. Irritative urinary symptoms, such as urgency, dysuria, and frequency without hematuria, particularly in the absence of infection, should lead to an evaluation for bladder cancer. Larger tumors may cause bladder outlet obstruction or ureteral obstruction resulting in hydronephrosis. Bilateral ureteral obstruction leading to azotemia is rare. Bladder tumors may cause pelvic pain by infiltrating regional nerves or bone, may cause lymphedema as a result of lymphatic obstruction from lymph node metastasis, or may present as manifestations of metastatic disease to bone, lungs, or liver. If bladder cancer is suspected, an intravenous pyelogram (IVP) should be undertaken to locate filling defects in the bladder and in the upper tracts. In addition, cystoscopy should be performed to locate the tumor and to facilitate biopsy for pathologic confirmation and to determine depth of invasion. Urinary cytologic analysis is a useful adjunct in the initial assessment and follow-up evaluation. Newer tests including an evaluation of the urine for bladder cancer antigens, such as bladder tumor antigen and nuclear matrix protein 22, and the genetic fingerprinting of exfoliated cells is under study. Evaluation of metastatic sites is essential, including abdominal pelvic CT, chest radiograph, and bone scan.
9:37 PM 0
MRCP Part 1 : Q4-6 : Answers
Question Number 4
Correct Answer: B
Explanation:
Deficiency of B2 is usually found in conjunction with deficiencies of other B vitamins. Isolated deficiency of riboflavin classically produces inflammation of the nasopharyngeal mucosa, cheilosis, angular stomatitis, glossitis, seborrheic dermatitis, and a normochromic, normocytic anemia.
Question Number 5
Correct Answer: D
Explanation:
Manifestations of Vitamin K deficiency include hypoprothrombinemia ,hemorrhaagic diathesis, an increased tendency to bleeding and a prolonged coagulation time. Vitamin K is required for gamma-carboxylation of glutamic acid residues of the procoagulant Factors II (prothrombin), VII, IX, and X and the anticoagulant factors protein C and protein S<br>Severe vitamin K deficiency can lead to a hemorrhagic diathesis that is characterized by prolongations of the PT and sometimes also the aPTT. The PT is more sensitive than the aPTT in detecting vitamin K deficiency states because Factor VII, the only one of the vitamin K-dependent factors that is in the extrinsic pathway of coagulation, is the most labile of these proteins.The two major sources of vitamin K are dietary intake and synthesis by the bacterial flora of the intestine. Therefore, in the absence of malabsorption, nutritional deficiency alone rarely causes clinically significant vitamin K deficiency. However, such a condition can arise when eradication of gut flora is combined with inadequate dietary intake. This situation typically occurs in critically ill patients in intensive care units who have no oral intake and are receiving broad-spectrum antibiotics for prolonged periods. Vitamin K deficiency can also develop in patients receiving total parenteral nutrition unless the infusions are supplemented with vitamin K
Question Number 6
Correct Answer: B
Explanation:
Diabetic retinopathy may be classified as nonproliferative or proliferative.Nonproliferative diabetic retinopathy is characterized by structural abnormalities of the retinal vessels including edema, exudates, and intraretinal hemorrhages. Proliferative diabetic retinopathy, on the other hand, results in optic disc, retinal, or iris neovascularization.Neovascular tissue contains both a vascular and a fibrous component. The vascular component may cause hemorrhage while the fibrous component may may cause traction on the retina.The major vision-threatening complications therefore include macular edema, macular ischemia, neovascularization with preretinal or vitreous hemorrhage, retinal detachment and neovascular glaucoma.
4:52 AM 0
USMLE step 1 : 23-24 Answers
Question Number 23
Correct Answer: A
Explanation:
The clinical features are typical of facial nerve paralysis. Muscles of the lower half of the face are typically weakened. The normal folds and lines around the lips, nose, and forehead are ironed out, and the palpebral fissure is wider than normal. When the patient attempts to smile, the lower facial muscles are pulled to the opposite side. This distortion of the facial muscles may give the false appearance of deviation of the protruded tongue or the open jaw. Saliva and food are likely to collect on the paralyzed side
Question Number 24
Correct Answer: C
Explanation:
Pain typical of trigeminal neuralgia occasionally affects patients with lesions in the brain stem as a result of multiple sclerosis. They may also occur with vasculitis involving the descending root of the fifth cranial nerve. Trigeminal neuralgia usually occurs after other symptoms of MS. Of all patients with MS, however, about 10% have facial pain as a presentation, and other symptoms of MS may not appear for 6 years.
Question Number 25
Correct Answer: B
Explanation:
Glossopharyngeal neuralgia (known as tic douloureux of the ninth cranial nerve) is characterized by paroxysms of severe pain in the region of the tonsils but may also affect the posterior pharynx, back of the tongue and middle ear. Glossopharyngeal neuralgia is rare, occurring about 5% as often as trigeminal neuralgia. Pain is typically precipitated by swallowing, talking, or touching the tonsils or posterior pharynx. The attacks last only a few seconds but occasionally are prolonged for several minutes. The frequency of attacks varies from many times daily to once in several weeks. Long remissions are common. The diagnosis of glossopharyngeal neuralgia can be made from the description of the pain. The only differential diagnosis of any importance is neuralgia of the mandibular branch of the fifth nerve. This differentiation may be established by stimulation of the tonsils, posterior pharynx, or base of the tongue or when the pains are relieved by spraying the affected area with local anesthetic. When the membrane becomes anesthetized, the pains disappear and they cannot be pre cipitated by stimulation with an applicator. During this period, the patient can swallow food and talk without discomfort. The paroxysms occur at irregular intervals and there may be long remissions. During a remission the trigger zone disappears. The pains almost always recur unless they are prevented by medical therapy or the nerve is sectioned surgically. The disease does not shorten life, but affected patients may become emaciated because of the fear that each morsel of food will precipitate a pain paroxysm.
1:58 AM 0
USMLE step 1 :20-22:Answers
Question Number 20
Correct Answer: D
Explanation:
While the above the above clinical features are suggestive of systemic lupus the presence of positive antinuclear antibody (ANA) in the absence of a better diagnosis often represents the most practical way to make a clinical diagnosis. In patients with signs of nephritis (e.g. edema, oliguria, hypertension, dysmorphic RBCs/RBC casts, or significant proteinuria) a prompt evaluation of renal function is indicated. This should include electrolytes, throat culture, antistreptococcal antibodies, complement studies (C3 /C4 ), and anti-nuclear antibodies (ANA). Further evaluation and treatment depend on the results of these studies. Features of systemic lupus include Malar (butterfly) rash Discoid rash Photosensitivity Oral/nasopharyngeal ulcers Nonerosive arthritis Pleuritis pericarditis Renal disorder - proteinuria or cylindruria Neurologic disorder - psychosis or seizures Hematologic disorder - hemolytic anemia, leukopenia (less than 4,000), lymphopenia (less than 1,500), thrombocytopenia (less than 100,000) Immunologic disorder Positive antinuclear antibody (ANA) in absence of drugs known to cause positive ANA
Question Number 21
Correct Answer: D
Explanation:
The hypoglossal nerve is the main motor nerve to the tongue. The palatoglossus muscle, however, is supplied by the pharyngeal plexus of nerves, the motor branch of which is the pharyngeal branch of the vagus. Unilateral injury to the nucleus results in atrophy and paralysis of the muscles of half of the tongue. When the tongue is protruded, it deviates toward the paralyzed side, and while protruded, movement toward the normal side is absent. The nerve passes through the anterior condyloid foramen (the the hypoglossal canal which lies just medial to the jugular foramen) after it emerges from the medulla oblongata between the pyramid and olive.
Question Number 22
Correct Answer: B
Explanation:
The long thoracic nerve arises from the fifth, sixth, and seventh cervical roots. It is the motor nerve to the serratus anterior muscle.Lesions of the long thoracic nerve are most common in men who do heavy labor. The nerve may be injured by continued muscular effort with the arm extended or by carrying heavy sharp-cornered objects on the shoulder. Injury of the nerve following acute or chronic trauma is characterized by weakness in elevation of the arm above the horizontal plane. Winging of the scapula is a constant sign when the arm is fully abducted or elevated anteriorly. Winging is usually absent when the arm is held at the side.
7:06 PM 0
Q 11-13 : Answers
Question Number 11
Correct Answer: E
Explanation:
The finding of a a non-compressible superficial superficial femoral vein is indicative of thrombosis of this vein which is the major vein draining the lower limb. Once a diagnosis of Deep vein thrombosis has been made by venography or ultrasonography , baseline CBC, PTT, and INR levels should be obtained. Heparin should be administered Warfarin should be started on the evening of Day 1, and the dose adjusted to obtain an INR level of 2.0 - 3.0
Question Number 12
Correct Answer: D
Explanation:
Ventilation/Perfusion scintigraphy should be performed to rule out pulmonary embolism. The characteristic feature of emboli are mismatched defects.
Question Number 13
Correct Answer: A
Explanation:
Depending on culture sensitivities, the therapy directed against Group A streptococci usually is penicillin G, 1 to 2 million units intravenously every 2 to 3 hours. Penicillin-allergic patients may be treated with a cephalosporin such as cefazolin. Vancomycin may be used in cases in which cross-reactivity between penicillin and cephalosporin is of concern, If Haemophilus infiuenzae infection is suspected, then ampicillin is administered in six divided dosages. Alternatively, because of recent emergence of beta-lactamase-producing ampicillin strains, a cephalosporin (cefuroxime or cefotaxime) may be chosen. In the course of penicillin allergy, trimethoprim sulfameth-oxazole may be a treatment option in this select setting
10:02 AM 0
Q 17-19 Answers
Question Number 17
Correct Answer: C
Explanation:
Acute leukemias are commoner in Down's syndrome. Experienced morphologists can reproducibly classify about 70% of acute leukemias as either ALL or AML by the blast appearance on Romanovsky-stained smears based on nuclear and cytoplasmic features. The most important morphologic characteristic in identifying blasts is the nuclear chromatin pattern. The chromatin in lymphoblasts is more clumped and irregularly distributed. The presence of nucleoli varies. Nucleoli may be indistinct or appear prominent because of chromatin condensation along the nucleolar and nuclear membranes
Question Number 18
Correct Answer: B
Explanation:
Vitiligo is a circumscribed amelanotic macule that occurs in a symmetrical distribution around body orifices and over bony prominences is familial in a third of cases. Although most patients with vitiligo are healthy, there is an increased association with certain autoimmune conditions such as thyroiditis, hyperthyroidism, Addison's disease, pernicious anemia, and diabetes mellitus. Melanocytes are absent from the vitiliginous macules The severity of vitiligo differs with each individual. Light skinned people usually notice the pigment loss during the summer as the contrast between the affected skin and sun tanned skin becomes more distinct. People with dark skin may observe the onset of vitiligo any time.
Question Number 19
Correct Answer: A
Explanation:
Felty's syndrome is a triad of rheumatoid arthritis, splenomegaly, and neutropenia. This is secondary to immunoglobulin directed toward neutrophils. Patients with Felty's syndrome respond to splenectomy with an increase in their neutrophil count. Splenomegaly with peripheral trapping and destruction of neutrophils is also seen in lysosomal storage diseases and in portal hypertension.
9:48 AM 0
Answers : Q 14-16
Answer :
Question Number 14
Correct Answer: B
Explanation:
In pregnancy venostasis is a most controllable factor in preventing venous thrombosis and pulmonary embolism. Pregnant women are susceptible to venostasis in the lower extremities, because the gravid uterus interrupts flow through the iliac veins and inferior vena cava. The primary means of alleviating venostasis is elastic compression of the legs. Elastic bandages are usually recommended to compress all varices from the time they appear until after delivery. In addition to elastic support, the patient is instructed to avoid prolonged standing. Frequent elevation of the legs and leg exercises have also been
Question Number 15
Correct Answer: C
Explanation:
Lymphatic filariasis is caused by a nematodal infection with Wuchereria or Brugia species. It occurs in endemic areas throughout the tropical parts of the world, with a predilection for developing countries where poor socioeconomic conditions are favorable for mosquito vector breeding. A definitive diagnosis often depends on the parasitologic demonstration of the microfilariae in the blood. Presentation may vary from very insidious to severe. Pitting edema progresses to brawny edema, and thickening of subcutaneous tissue and hyperkeratosis. In many areas the most common chronic manifestation is a hydrocele. Annual single-dose co-administration of two drugs (ivermectin + albendazole) reduces blood microfilariae by 99% for a full year; even a single dose of one drug administered annually can result in 90% Effective diagnosis of infection with these parasites is required both for administration of drugs to infected individuals and for monitoring of control programs. There has been considerable effort expended in developing other forms of diagnosis, in particular immunoassays for measuring antibody and circulating parasite antigen as well as molecular-biology-based assays for detecting parasite DNA
Question Number 16
Correct Answer: E
Explanation:
Systemic mastocytosis results in mast cell infiltration of the skin, gastrointestinal mucosa, liver, and spleen. Cutaneous manifestations include small, reddish-brown papules which would be characterized histopathologically as having excess numbers of mast cells. Histamine-mediated hypersecretion of gastric acid accounts for an increased incidence of gastritis and peptic ulcers in patients with systemic mastocytosis. Bone pain, organomegaly, or lymphadenopathy may also be seen. In addition to documentation of mast cells in various organs, biochemical confirmation can be made by urine collection for histamine metabolites or by measuring increased blood levels of histamine or mast cell-derived neutral protease tryptase. Mast cell disease may be indolentor more aggressive characterized by mast cell infiltration of liver and spleen that may lead to mast cell leukemia
9:08 AM 0
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