INTERNAL MED.(Diagnostic) 201-291

A 75-year-old man has been recently diagnosed with Parkinson's disease and started on levodopa (L-DOPA), which has helped his tremor and bradykinesia significantly. However, in the past week he had a fall shortly after getting out of his chair, during which he briefly blacked out, and afterwards was sweating and felt cold. Which of the following side effects most likely explains the fall?

A 6-year-old boy has a 1-month history of aching bones and muscle pains. On examination he appears pale and has multiple bruises along his legs. He has extensive lymphadenopathy. Blast cells are seen on the blood film. What is the most likely diagnosis?

A 62-year-old woman presents to the emergency department with collapse. She felt dizzy when she tried to stand up from a sitting position. She did not lose consciousness. She denied any visual disturbances, headache or head injury. She also complained of fatigue over the past month. She takes only omeprazole and paracetamol. An electrocardiogram (ECG) showed normal sinus rhythm. Her blood pressure was 102/50 mmHg. A blood test revealed the following: Na+ 126 mmol/L, K+ 6.5 mmol/L, urea 10.0 mmol/L, and creatinine 139 μmol/L. What is the most likely diagnosis?

A 32-year-old woman presents to the GP with a 3-month history of non- productive cough and breathlessness on exertion. She also complains of fatigue, weight loss and joint pain. She smokes 15 cigarettes/day. She has not travelled to any foreign countries recently. On examination, fine interstitial crackles are heard on the anterior chest wall. There are multiple tender red lumps on both shins. What is the most likely diagnosis?

A 74-year-old man is admitted to hospital with an acute-on-chronically ischaemic leg and started on intravenous heparin. Blood tests taken 5 days later show platelet levels have dropped from 250 to 54 x 109. What is the most likely cause for thrombocytopenia in this patient?

A 63-year-old male smoker, on diuretics for essential hypertension, presents to the emergency department with chest pain. His ECG is presented to you. Amongst other signs, you notice T-wave inversion. Which of the following does not cause T-wave inversion?

A 72-year-old man is bed-bound following a severe stroke several years previously and lives in a nursing home with full-time care. The staff noticed that over the last 8 days he didn't pass any stool motions until this morning, when there was profuse, offensive liquid stool. They are concerned this may be infective diarrhoea. On examination there is hard stool in the rectum. What is the most likely diagnosis?

A 42-year-old woman with known HIV presents with a 3-week history of dry cough and increasing breathlessness. She is now unable to walk 100 yards without becoming short of breath. You suspect pneumocystis pneumonia. Which of the following tests is the best way to confirm the diagnosis?

A 43-year-old woman presents with an acute sharp, central chest pain radiating to the left arm that is worse on inspiration and at night. She reports that it is preventing her coughing which, in turn, is prolonging a recent chest infection. On examination, her chest exhibits vesicular breath sounds with bi-basal crackles. Her electrocardiogram (ECG) shows widespread concave ST elevation in sinus rhythm. Which of the following is the most likely diagnosis?

A 70-year-old woman presents with hip pain following a fall. The fall appears to have been related to alcohol ingestion and, whilst the history is vague, she denies loss of consciousness and does not seem grossly confused, nor is there evidence of infection. She is a smoker and has a history of ischaemic heart disease and depression. A hip fracture is ruled out and she is admitted for rehabilitation purposes. On day 3, however, the nurses report that she is increasingly sleepy and muddled. On examination, observations are stable, she is apyrexial, her Glasgow Coma Score (GCS) is 12, and on neurological examination, she appears to have some mild left arm and leg weakness with normal or brisk reflexes. There is no hemianopia or other neurological deficit. Which of the following is most likely to explain the changes?

A 40-year-old woman presents to the GP with a history of weight loss and irritability. She has lost 1 stone in the past 2 weeks. She claims that she has a normal appetite. She also complains of blurring of the vision for the past month. On examination, she has a ''staring look'' with lid lag and lid retraction. What is the most likely diagnosis?

A 68-year-old woman recently diagnosed with multiple myeloma presents to her GP with progressively increasing breathlessness, exercise intolerance and ankle swelling. On examination, there is bilateral pitting leg oedema to her thighs, ascites and raised JVP. The apical impulse is impalpable. An ECG shows diffusely diminished voltage. Chest X-ray is normal and the echocardiogram shows small thick ventricles and dilated atria with a thickened interatrial septum. The ventricular myocardium has a granular sparkling texture on echo, and minimal fluid in the pericardia} space is noted. What is the most likely diagnosis?

A patient has broad-complex tachycardia features resembling ventricular tachycardia rather than supraventricular tachycardia with a bundle-branch conduction defect. Which of the following makes Wolff-Parkinson-White the most likely 11nderlying diagnosis?

A 60-year-old man with unstable angina on long-term digoxin was being monitored on the ward with telemetry when the monitor displayed a tachycardia of 180 bpm. The printout showed discrete normal morphology P waves before each QRS complex and there was an acceleration in the rate after initiation of the arrhythmia. The QRS width was 0.12 s. Which of the foil owing is the most likely arrhythmia?

A 25-year-old medical student noticed that he had a murmur when he tested his new stethoscope. On assessment in the cardiology clinic, he was found to have a harsh systolic murmur over his precordium, which did not change with inspiration. ECG showed features of biventricular hypertrophy. What is the most likely diagnosis?

A 25-year-old man presents to the emergency department wth a 1-week history of fever and myalgia. He had travelled to Chile 8 weeks ago. On examination there are no positive findings, although the patient recollects that his right eyelid was swollen for a few weeks after be left Chile. ECG reveals non-specific, T-wave changes in all leads. What is the most likely diagnosis?

Cardiac catheterisation is performed on a 25-year-old man with a systolic murmur but no symptoms. ECG and chest X-ray are normal. The findings are as follows (pressures mmHg): aorta, 125/70; left ventricle, 120/12; right atrium, mean 8; right ventricle, 40/8; pulmonary artery, 44/14; pulmonary capillary wedge, mean 13. Saturations(%): aorta, 97; superior vena cava, 68; right atrium, 70; right ventricle, 82; pulmonary artery, 85. What is the most likely cardiac diagnosis?

A 30-year-old postman with hypertension but normally in good health presents to the emergency department with sudden severe breathlessness and sweating. Chest examination reveals bilateral basal crackles. He improves with diamorphine and frusemide (furosemide ). Electrocardiograms (EC Gs) and cardiac enzymes are normal. He develops two further episodes of pulmonary oedema which respond well to diuretics. The most likely cause of pulmonary oedema is?

A 38-year-old man presents for review. His only previous history of note has been recurrent shoulder subluxation. His main complaints are tiredness and increasing dyspnoea on exertion. The nursing clerking on admission notes that he seems very tall and thin, his height is described as 1.93 m (6ft 4 inches). On examination his blood pressure is 165/70 mmHg, he has left ventricular hypertrophy, a low-pitched apical diastolic murmur and an early systolic apical ejection murmur. What diagnosis fits best with this clinical picture?

An 82-year-old man was admitted to the Emergency department from a local church service. He fainted and another parishioner, who is a trained first-aider, reported that he was pulseless for a few seconds after the attack. On examination his blood pressure was 165/95 mmHg (past history of hypertension), he had no murmurs on auscultation of the chest and carotid auscultation was also normal. Outpatient 7-day ambulatory cardiac rhythm monitoring was arranged, which is now reported as normal. What diagnosis fits best with this presentation?

A 22-year-old student is admitted by ambulance from a local night club. He has no previous medical history of note and is adopted so is unaware of his family history. Bystanders who have accompanied him say that he suffered sudden collapse while dancing. Bouncers at the club claim that they couldn't feel a strong pulse during his period of unconsciousness. On admission his blood pressure is 120/60 mmHg, and pulse is 80 bpm and regular. ECG looks normal, corrected QT interval is 0.6 s. What diagnosis fits best with his clinical picture?

A 72-year-old man presented with an episode of collapse. He had experienced two similar episodes recently, each lasting about one minute. Four years previously he suffered an anterior myocardial infarction. On examination he was orientated and symptom-free with a regular pulse rate of 80 beats per minute (bpm), blood pressure 140/80 mmHg, and the apex beat was displaced to the left. There was an apical systolic murmur. There were no signs of trauma. The electrocardiogram (ECG) showed sinus rhythm, Q waves, and ST segment elevation anteriorly without reciprocal depression. What is the diagnosis?􀀴 Acute anterior myocardial infarction

You are asked to review a 19-year-old woman who presents with increasing shortness of breath on exercise. She is from a travelling family and has rarely encountered medical care. On examination she appears of short stature with extra skin folds around her neck, and appears to have failure of secondary sexual development. Her blood pressure is raised at 165/100 mmHg. She reports that her legs feel tired all the time and she has occasional chest pain on exercising. Which of the following cardiac diagnoses fits best with her clinical condition?

A 45-year-old man attends for review. He has been suffering increasing shortness of breath over the past few years. He is a non-smoker who drinks 20 units per week of alcohol and has no significant past cardiovascular history. Now he presents with what seems to have been a transient ischaemic attack (TIA), with weakness and co-ordination problems affecting his left side, which have resolved over the past 24 hours. On examination blood pressure is 142/95 mmHg and he is in sinus rhythm. There is no opening snap, but a diastolic murmur is heard which changes in character according to posture. Bloods are unremarkable, including Creactive protein ( CRP), which is in the normal range. Which of the following diagnoses fit best with this clinical picture?

30-year-old man is being investigated for hypertension. A combination of BPs estimated by colour flow Doppler and measured values are listed below. Observed BPs: L V 200/10 mmHg, Ascending aorta 200/70 mmHg, Right arm 190/70 mmHg, Right femoral artery 110/70 mmHg. Which of the following is the most likely diagnosis?

A 42-year-old man with the features of congenital myotonic dystrophy comes to see you for review. He has suffered from mild intellectual impairment, frontal balding typical of the disease and increasing muscle weakness with increased muscle tone over the past few years. Most recently he has suffered from a number of episodes of syncope. On examination his BP is 129/70 mmHg, his pulse 55 BPM, there are no other significant findings on cardiovascular examination. What ECG findings might you most commonly expect to see in this case?

A 67-year-old man attends the cardiology clinic. He has been suffering some angina-type chest pain on going out in the cold air and is worried that he might have coronary artery disease. There is a past medical history of smoking 20 cigarettes per day, and hypertension which is managed with ramipril 10mg daily. His GP has sent an ECG which appears to show that he is in left bundle branch block. What would you expect to hear on auscultation?

A 70-year-old man presents with severe tearing back and chest pain which came on very suddenly. He has a past medical history of hypertension for which he takes ramipril 10mg daily, amlodipine 5mg, and he smokes 30 cigarettes per day. On examination he is in severe pain, his BP is 155/85 mmHg, he has bilateral upgoing plantars and 4/5 weakness affecting left ankle dorsiflexion. He appears to have a pericardia) rub. Which of the following features is most suggestive of dissecting aortic aneurysm?

A 54-year-old male with type 2 diabetes mellitus reports 3 months of exertional chest pain. His physical examination is notable for obesity with a body mass index (BMI) of 32 kg/m2, blood pressure of 150/90, an S4, no cardiac murmurs, and no peripheral edema. Fasting glucose is 130 mg/dL, and serum triglycerides are 200 mg/dL. Which of the following is most likely in this patient?

You find an 80-year-old man collapsed in the street. He is unresponsive and is making a snoring sound. An ambulance has been called but has yet to arrive. Which of the following is the best course of action?

A 34-year-old woman presents to the GP complaining of a new rash. The skin under her arms and on the back of her neck is dark and velvety in texture. She has a past medical history of diabetes for which she takes insulin. What is the most likely diagnosis?

A 64-year-old woman is an inpatient on a surgical ward foil owing an above- knee amputation. The nursing staff said she vomited earlier and she has been unresponsive since her operation a few hours ago. On examination, you noticed her pupils are small and she has a respiratory rate of 5 breaths/ min. Which of the following is the most likely reason for this clinical picture?

An 80-year-old man attends the general practice for an annual check-up of his hypertension. He gingerly tells you all about his ''left ventricular hyperthingummy''. You check him and his records for confirmatory signs and symptoms. Which of the following is NOT a sign of left ventricular hypertrophy?

A 43-year-old man presents with intermittent haematuria. On examination of the abdomen, bilateral masses are felt and an ultrasound reveals polycystic kidneys. You explain the syndrome to him. He is concerned that his son may develop the disease. He does not believe his wife suffers from the condition. What is the probability that his son will develop the disease?

You are examining a tearful young child who has fractured her arm. On auscultation you hear an ejection systolic murmur. There is no cyanosis. Which of the following prevents you reassuring her calm dad that his daughter has no serious heart problem?

A 59-year-old man is admitted to the emergency department following a fall. He complains of increased tiredness and jerking movement of his legs, which led to his fall from the staircase. He is a smoker. On arrival, he has an oxygen saturation level of 76% in air, and an arterial blood gas reading-demonstrates: pH 7.40, Pa02 6 kPa, PaC02 9.3 k.Pa, HC03 35 mmol/L on room air. His respiratory rate was 20/min. What does this blood gas result show?

A 55-year-old woman presents with mild cognitive impairment and disinhibition without significant mood change. She also has falls and urinary incontinence. She has no major past medical history or medications, and has never smoked or drank much alcohol. On examination, there are no cranial nerve or arm defects, however the legs appear to have increased tone, upgoing plantars and clonus bilaterally with some weakness of hip and knee flexion bilaterally. Which of the following diagnoses may explain the picture?

A 32-year-old woman presents to her GP complaining of tingling and numbness around her mouth for 1 week. Occasionally, she also develops painful carpal spasm. She has a past medical history of Graves disease for which she just recently had subtotal thyroidectomy. What is the most likely diagnosis?

A 60-year-old woman presents to her GP with a chronic cough associated with thick, yellow sputum for the past year. Sometimes, the sputum is blood-tinged. She had been prescribed multiple courses of antibiotics but they did not seem to help. She had a past medical history of severe pneumonia that required admission to the intensive care unit for 20 days. On chest examination, there are inspiratory crackles throughout the lung fields, with normal vesicular breath sounds. Which of the following is the most likely differential diagnosis?

A 56-year old man has a myocardial infarction the day after a hernia repair. You request an ECG and then compare it to his pre-admission trace. You notice ST-segment changes in leads II, III and a VF. In which part of the myocardium is the infarct?

A 19-year-old female university student presents with problems in both arms and difficulty walking. Since starting her course she has bad difficulty writing, typing, and other such activities, and thus has struggled to keep up with the workload. She says the arms have ''felt unusual'' for around 6 months. She describes finding small burns and blisters on her arms that she can't remember getting in the first place. In the last few weeks she has also fallen twice when walking up the stairs. The only other thing she describes is some mild occipital headaches that have increased in frequency lately. She is otherwise fit and well. On examination, there is a loss of pinprick sensation found throughout the arms and on the back to around T3 level. Her hands appear to have some element of small muscle wasting and there is some loss of power throughout the arms. Reflexes are hard to elicit or possibly absent. In the legs, there is some mild symmetrical weakness, and the knee reflexes appear brisk. Plantars appear equivocal. What is the most likely diagnosis?

A 32-year-old man is diagnosed with Hodgkin's lymphoma following a recent history of weight loss and night sweats. Computed tomography (CT) staging scan shows disease in the mediastinum bilaterally and some abdominal lympbadenopathy, including the spleen, but no evidence of disease in extranodal sites. What is his stage of disease?

A 68-year-old obese woman is not coping at home and presents to the emergency department foil owing a fall. On examination, she has a weak, regular pulse and an ejection systolic murmur. You try to lean her forward and palpate her apex beat in expiration but she gets flustered and complains of a sore back and shortness of breath. A neurological examination is unremarkable and her haemoglobin level is 13.2 g/dl. What is most likely wrong with her?

A 70-year-old man presents with multiple widespread tense blisters measuring between 0.5 cm and 5 cm in diameter. They are localised mainly to the arms and legs, with some lesions on the chest. They appeared over weeks, preceded by itchy urticaria! lesions. A few lesions have burst and have left not much behind. There is a history of osteoarthritis of the knees for which he takes diclof enac, and he has not changed any medication in the past year. A subsequent biopsy of a bulla shows splitting at the dermoepidermal junction. What is the diagnosis?

A 35-year-old man presents to the GP with increasing fatigue for 3 months. He fmds himself waking up choking a few times at night. He was told by his partner that he snores quite loudly most nights. He denies any weight loss. He smokes 30 cigarettes/day, drinks 2 pints of beer every night and has a body mass index of 32. What is the most likely differential diagnosis?

A 73-year-old man has been admitted with severe sepsis and acute renal failure secondary to a urinary tract infection. He has been treated with intravenous antibiotics and fluid resuscitation but the following day you are called to see him as he is worse. He looks extremely unwell. His airway is patent and he has laboured breathing at a rate of 22 breaths/min. His saturations are 98o/o on air and his chest sounds clear. His pulse is 120 bpm and blood pressure 85/55 mmHg. His capillary refill rate is 4 seconds. His urine output has been 40 ml in the last 5 hours. You see from his blood tests that his creatinine level has increased slightly. You take an arterial blood gas reading. Which of the following is the most likely result?

A 61-year-old woman presents to the walk-in clinic with a history of tight, sternal chest pain ''appearing out of the blue''. Such episodes have occurred at different times throughout the day and rarely last longer than a few minutes. They do not correspond to hard exercise. The patient has no cardiac history to date. Her electrocardiogram (ECG) has not detected any abnormalities and 2 days have passed since the last episode. Which of the following is the next best step in her management?

A 37-year-old woman is being investigated for weight loss and diarrhoea. Barium enema shows ''cobble-stoning'', rose thorn ulcers and colonic strictures at intermittent points throughout the colon. What is the most likely diagnosis?

You are asked by your registrar to see a 40-year-old woman and report back your findings. On examination, you struggle to find an apex beat although heart sounds 1 and 2 were audible with no murmur. On inspection, her electrocardiogram (ECG) is normal except for inverted Pwaves. What is the most likely reason for these findings?

A 53-year-old man, who has had some lower back pain and sciatica into his right leg for the past year, presents with a 2-day history of leg weakness and severe pain. On examination, which of the following signs does NOT make you think of cauda equina syndrome?

You are called in the middle of the night to see a 49-year-old man with known alcoholic liver disease admitted 2 days previously. He is shaking, sweating, tachycardic, apyrexial and believes he is seeing spiders crawling across the ceiling. What is the most likely diagnosis?

A 59-year-old woman with advanced metastatic breast cancer presents to the emergency department with severe abdominal pain. She has not opened her bowels for 7 days and feels constipated. She has also noticed that she has been passing water more frequently but has not been incontinent. On rectal examination there is no loss of anal tone and normal sensation. What is the most likely diagnosis?

A 19-year-old female presents to the emergency department with a severe headache, photophobia, neck stiffness and a temperature. She is treated for bacterial meningitis with intravenous ceftriaxone. Blood cultures grow Neisseria meningitides. The next day, she starts bleeding from around her intravenous cannula and venepuncture sites. Which of the following investigation results would you NOT expect in disseminated intravascular coagulation?

A 67-year-old man presents with painless rectal bleeding for the past 2 months. It occurs mainly on defecation, and is bright red in the pan and on the toilet paper. A digital rectal examination is unremarkable. What should your management be?

A 23-year-old fmal year law student presents to the GP with a cough productive of foul green sputum. He also complains of breathlessness on exertion. He has had an average of five respiratory tract infections per year for the past 2 years. As a child, he could not tolerate dairy products. On examination, finger clubbing is present and there is dullness to percussion of the right upper lung zone with widespread bilateral wheeze. What is the most probable diagnosis?

A 50-year-old overweight pub landlord presents with an acutely painful swollen red hot first metatarsophalangeal joint on the left. You suspect gout. Which of the following would confirm this on microscopy of a joint aspirate?

A 27-year-old woman who works in the city as an investment banker presents with difficulty walking, and a tremor in the right hand. It has come on over the last 4 days and she is now unable to get to work safely. She denies any preceding respiratory or gastrointestinal infection or any abnormal stress at work or in her personal life; however, she says that 5 months ago she had some pain and blurring in the left eye for about 10 days, but she put that down to ''sinusitis'', kept working, and things returned to normal. Her grandfather, who died 2 years ago, had Parkinson's disease for some time, and she is concerned that this could be the same thing. On examination, in her arms, there is normal tone, power and sensation, but there is indeed a tremor in the right hand on testing coordination, which gets worse on approaching the target, and is absent at rest. In the legs, there is normal power, but decreased light touch sensation bilaterally and a loss of vibration sense and proprioception up to the ankles. What are you most concerned is the diagnosis?

A 33-year-old woman with multiple sclerosis (MS) is having problems with painful spasms and disabling spasticity in her left leg. Which of the following medications is most likely to help?

A 65-year-old woman presents to hospital with left-sided weakness of sudden onset. She is a type II diabetic, smokes 20 cigarettes/day and has high blood pressure. On examination, power in the left arm is O throughout although the left leg shows a power of 3 at the hip and knee and 4 at the foot. Her reflexes are reduced throughout, and sensation is absent in the arm and reduced in the leg. In the cranial nerve examination she is unable to see on her left-hand side, and the lower half of her left face is weak (she can raise her eyebrow). There is no dysphasia. Which vascular territory is affected?

A 45-year-old man presents to the GP with a 4-month history of a productive cough with exertional breathlessness. He denies haemoptysis or weight loss. He has a 20 pack/year smoking history. On examination, fine crackles are heard throughout the whole lung field. What is most likely differential diagnosis?

A 54-year-old woman presents to her GP complaining of repeated incidents of burning central chest pain. It mainly occurs when she lies down to go to bed at night. She is overweight with a body mass index of 40. She uses glyceryl trinitrate (GTN) occasionally but it doesn't always relieve her symptoms. She doesn't report any shortness of breath or palpitations and examination is unremarkable. What is the most likely diagnosis?

A 78-year-old woman presents with palpitations that began an hour ago. She feels clammy to the touch. Whilst she is clutching your hand and telling you her past medical history, you check her observations on the bedside monitor. You notice that her heart rate is 230 bpm and regular. The QRS complexes are narrow and no P-waves are noted. What is the most likely arrhythmia?

A new blood test is being developed to help diagnose sarcoidosis. In a trial 100 patients have been tested. The trial produces 20 positive results and 80 negative results. Of the 20 positive results, 1 0 of them are false positives. Of the 80 negative results, 10 of them are false negatives. What is the sensitivity of this test?

A 34-year-old woman, who is known to be human immunodeficiency virus (HIV) positive, presents with multiple lesions on her face. The lesions are raised and shiny, non-tender and around 3 mm in diameter. They have an umbilicated centre. What is the most likely diagnosis?

A 52-year-old man with a history of alcohol excess presents to his GP because he cannot fully extend his ring finger on his right hand (neither actively nor passively). Since the fmger is permanently partially flexed he can no longer place his hand flat on a flat surface. Which of the foil owing is the most likely diagnosis?

A 34-year-old woman with systemic lupus erythematosus (SLE) has had multiple miscarriages and now presents with a painful right swollen leg. A compression ultrasound scan confirms deep vein thrombosis. Which blood test may now be indicated?

A 42-year-old woman attends to her GP complaining of non-specific abdominal pain and an increasing abdominal girth. She is found to have a large mass in her right lower abdomen and ascites on transvaginal ultrasound imaging. Which of the following tumour markers would be most useful?

A 67-year-old man presents for evaluation of worsening dyspnea. The patient reports that his symptoms have been worsening over the past several months. He also mentions that he has developed some swelling in his legs and notes that he is easily fatigued. His medical history is remarkable for type 2 (non-insulin-dependent) diabetes mellitus, presumed cytogenic cirrhosis, and ''arthritis'' in his hands. The patient denies ever using alcohol. On physical examination, the patient's vital signs are normal; examination of the jugular venous pulse shows the height to be 10 cm; no thyromegaly is present; pulmonary examination reveals faint basilar crackles; cardiac examination shows nondisplaced point of maximal impulse and no audible murmur; no hepatosplenomegaly is noted; and 2+ bilateral lower extremity edema is noted. An ECG is unremarkable. An echocardiogram reveals normal ejection fraction and normal valvular function. You order lab work that includes iron studies and make the diagnosis of hemochromatosis. What is the pathogenesis of heart failure in this patient?

A 76-year-old woman presents to the emergency department for evaluation of nausea and mild epigastric pain that started suddenly 45 minutes ago. She denies having chest pain. Her medical history includes diabetes mellitus, hypertension, and hyperlipidemia. An electrocardiogram is interpreted as being normal. For this patient, which of the following statements regarding the diagnosis of unstable angina is false?

A 67-year-old man with type 2 diabetes and a long history of cigarette smoking develops severe exertional chest pain. Cardiac catheterization reveals three-vessel disease. Twenty-four hours later, he develops abdominal pain, painful toes, and a rash. On examination, he has purple discoloration of the second and fourth toes on his right foot and a lacy rash on both legs. Laboratory results are as follows: Hb, 13; HCT, 39; WBC, 9.0; BUN, 26; and Cr, 1.8. What is the most likely diagnosis for this patient?

A 16-year-old male becomes unresponsive immediately after being hit in the chest by a baseball in a local game. A family member reports that the patient has a ''heart murmur.'' He takes no medications. The emergency medical service is called and finds the patient to be pulseless. Resuscitation attempts are started and are unfortunately unsuccessful. Which of the following is the most likely mechanism behind this patient's cardiac arrest?

A 26-year-old woman is being evaluated for dyspnea, which she experiences when she engages in physical activity. She has been having these symptoms for the past 4 months. She denies having chest pain, orthopnea, or paroxysmal nocturnal dyspnea. The patient's medical history is significant for her having one episode of atrial fibrillation 1 month ago. Her physical examination shows fixed splitting of S2 and a 2/6 systolic murmur in the pulmonic area. An electrocardiogram shows mild right axis deviation and an rSR' pattern in Vl. A chest x-ray reveals an enlarged right atrium and main pulmonary artery. Which of the following is the most likely diagnosis for this patient?