Because Pathology Need Not Be the Root of All Suffering
The image is a microscopic section of the heart with an acute myocardial infarction. The cardiac myocytes have coagulative necrosis, with preservation of architecture but with loss of nuclear basophilia. Associated with the coagulative necrosis is a extensive neutrophilic infiltrate (see black arrows in image below).
The timing of the infarct would be around 2-3+ days.
Question 116
A 65-year-old male with a past medical history of hypertension, hyperlipidemia, and a 30 pack-year smoking history sustains an episode of chest pain while golfing with friends. He tells his friends that it feels like someone is standing on his chest and he clenches his fist in front of his chest when he does so. In addition to the pain, he is nauseous and sweating. They try to convince him to call an ambulance, but he refuses. The pain stops about 4 hours after it began. Three days later, his wife finds him dead in bed when she awakes. He had no complaints the night before. Of the following, which is most likely to be found at autopsy?
A. A ruptured ventricular aneurysm
B. A ruptured ventricular free wall
C. A ruptured interventricular septum
D. A ruptured papillary muscle
E. A ruptured coronary artery
Answer: B (a ruptured ventricular free wall).
Explanation: the symptoms are consistent with an acute coronary syndrome (i.e., pressure sensation in the chest associated with sweating and nausea). .He has several risk factors for coronary artery atherosclerosis, including his age, sex, and history of hypertension, hyperlipidemia, and smoking history. At three days, rupture of the myocardium can occur. The most common location is the free wall, which would lead to cardiac tamponade and a relatively quick death. Rupture of the interventricular septum and papillary muscle are much less common, and, while both are emergencies, the survival time would be expected to be longer and the patient would most likely be symptomatic. A ventricular aneurysm develops at >2 weeks after the myocardial infarct, and, because it is composed of scar tissue, does not commonly rupture. While a ruptured coronary artery could cause a hemopericardium and death, rupture of the coronary artery is not normally associated with an acute myocardial infarct.
Question 117
A 61-year-old male comes to the emergency room complaining of abdominal pain. He says that over the past 3 months, he has had abdominal pain which occurs 1-2 hours after eating, and then dissipates. Because of this pain, he has not wanted to eat, and has lost 20 lbs in that time frame. He has a 40 pack-year smoking history and hypertension. Of the following, what is the most likely diagnosis?
A. Acute mesenteric ischemia
B. Chronic mesenteric ischemia
C. Abdominal aortic aneurysm
D. Atypical acute myocardial infarct
E. Vasculitis
Answer: B (Chronic mesenteric ischemia)
Explanation: the history of abdominal pain occurring after eating a meal is characteristic of mesenteric ischemia. Because the disease process has been going on for some time, the best diagnosis would be chronic mesenteric ischemia. The pain occurs because atherosclerotic narrowing of the celiac artery or superior mesenteric artery or both blocks blood flow, and, when increased blood flow is needed to facilitate digestion, it does not develop and ischemia occurs. An abdominal aortic aneurysm can cause abdominal pain; however, not so consistently associated with meals. An atypical acute myocardial infarct should be considered when an older male (or female) with risk factors for atherosclerosis presents with abdominal pain, but the clinical presentation would be acute, nor chronic. Vasculitis can involve the celiac or mesenteric vessels; however, it would be much more rare than atherosclerosis.
Question 118
A 41-year-old male who has been diagnosed with hypertension for 2 years presents to his physician complaining of weakness, which he says comes and goes. Physical examination reveals a blood pressure of 152/81 mmHg, but is normal otherwise, including normal heart and lung sounds. Laboratory testing reveals an elevated concentration of sodium and a decreased concentration of potassium in the blood. A CT scan of the abdomen reveals a nodule in the right adrenal gland Additional laboratory testing would most likely reveal an elevated concentration of which of the following?
A. Aldosterone
B. ACTH
C. Epinephrine
D. Renin
E. Beta natriuretic peptide (BNP)
Answer: A (aldosterone)
Explanation: patients with an aldosterone-secreting adrenal adenoma (or, with adrenal cortical hyperplasia) can develop secondary hypertension. While patients can have only hypertension, they can also have hypernatremia and hypokalemia, which are associated with episodic weakness. In these individuals, laboratory testing would reveal an elevated concentration of aldosterone. Reninomas occur in the kidney and can be associated with hypertension. Pheochromocytomas occur as a nodule in the adrenal medulla and secrete catecholamines, but are not associated with hypernatremia or hypokalemia, and the hypertension and related symptoms are episodic. While Cushing syndrome is a cause of secondary hypertension, and with a pituitary adenoma, patients could have an increased concentration of ACTH, the patient has no other features of Cushing syndrome (e.g., thin skin, osteopenia, obesity, round facies).