A 45-year-old man develops fever, cough with sputum production, night sweats, anorexia and weight loss. The expectorated sputum characteristically is foul smelling and bad tasting. Imaging shows he has developed an abscess in his lung. He is HIV negative.
All of the following organisms may cause lung abscess in this patient, except:
Correct Answer A:
Lung abscess can be caused by a bacterial infection that reaches the lungs in several ways. The most common is aspiration of oropharyngeal contents.
Patients at the highest risk for developing lung abscess have the following risk factors: poor dentition, seizure disorder and alcohol abuse.
In addition the following infectious etiologies of pneumonia may progress to parenchymal necrosis and lung abscess formation: Pseudomonas aeruginosa, Klebsiella pneumoniae,Staphylococcus aureus, Streptococcal pneumonia and Nocardia species.
Pneumocystis jiroveci (formerly Pneumocystis carinii) is an opportunistic bug that can cause lung abscess in HIV/AIDS patients by taking advantage of the patients weakened immune system.
A 51-year-old white woman with a history of hypertension and non-insulin-dependent diabetes mellitus presents to the emergency department with with short-term memory impairment and a blindness.
Patient exhibits Anton's syndrome secondary to occlusion of:
Correct Answer E:
This patient has developed a stroke due to bilateral occlusion of the posterior cerebral artery (PCA). The PCA supplies parts of the midbrain, subthalamic nucleus, basal nucleus, thalamus, mesial inferior temporal lobe, and occipital and occipitoparietal cortices.
Bilateral infarction in the distal PCAs produces cortical blindness (blindness with preserved pupillary light reaction). The patient is often unaware of the blindness or may even deny it (Anton's syndrome - a state in which they fervently believe they can see when they cannot). Tiny islands of vision may persist, and the patient may report that vision fluctuates as images are captured in the preserved portions. Rarely, only peripheral vision is lost and central vision is spared, resulting in "gun-barrel" vision.
A 55-year-old male who had an episode of atrial fibrillation that converted in the emergency department after 24 hours is asymptomatic and currently in sinus rhythm. He is in good health otherwise and has no history of hypertension, diabetes mellitus, heart failure, transient ischemic attack, or stroke.
What is the most appropriate management for this patient at this point?
Correct Answer A: The absolute rate of stroke depends on age and comorbid conditions. The stroke risk index CHADS , used to quantify risk of stroke for patients who have atrial fibrillation and to aid in the selection of antithrombotic therapy, is a mnemonic for individual stroke risk factors: C (congestive heart failure), H (hypertension), A (age 75), D (diabetes mellitus), and S (secondary prevention for prior ischemic stroke or transient attack - most experts include patients with a systemic embolic event). Each of these clinical parameters is assigned one point, except for secondary prevention, which is assigned 2 points. Patients are considered to be at low risk with a score of 0, at intermediate risk with a score of 1 or 2, and at high risk with a score 3. The patient in this question has a CHADS2 score of 0, which is low risk. Patient's of this age with lone AF lasting < 48 hours without clinical or imaging abnormalities, with no hypertension or other cardiovascular disease, or related pulmonary disease can be simply observed (choice A) and treatment with aspirin or warfarin is not indicated at this point.
→ Aspirin (choice A) is not indicated for a lone atrial fibrillation that occurred only once for less than < 48 hours in a patient < 60 years old, who is otherwise healthy. At presentation to ED a patient with AF should be given heparin as it is still possible for thrombus to occur before 48 hours, but once a patient returns to sinus rhythm < 48 hours of AF, and is otherwise younger and healthy, anti-coagulation treatment is not necessary.
→ Warfarin (Coumadin), with a goal INR of 1.5-2.5 (choice C), Warfarin, with a goal INR of 2.0-3.0 (choice D), Warfarin, with a goal INR of 2.5-3.5 (choice E) are all incorrect. Warfarin is indicated in patients who meet the CHADS2 score of 2 or higher.
A 50-year-old known hypertensive man was brought to the emergency department after a sudden feeling of numbness and weakness of his left arm and left half of the face. No other symptoms could be elicited and the patient could engage in dialogue, normally. Vital signs including blood pressure were stable. Left shoulder, upper arm, forearm and hand muscles have power of 2. Pain and temperature sensations are impaired on the left arm and left side of the face. No motor or sensory impairment could be detected on the right side or left lower side of the body. Visual fields were normal. The rest of physical examination was normal. Ischemic stroke was suspected.
Which of the following arteries is the most likely site of blockage?
Correct Answer B:
The superior division of the right middle cerebral artery (MCA) (choice B) is the most likely site of blockage in this patient. Patients with blockage of this division of MCA usually present with contralateral weakness and sensory loss on the arm and face. This division of the right MCA supplies the lateral surface of the right cerebral hemisphere above the lateral fissure but short of the superolateral portions, which are supplied by the anterior cerebral artery (ACA). Thus, motor, sensory and sensory association areas for the left upper part of the body (arm and face) are supplied by this division of MCA and weakness and sensory impairment are expected to affect these parts of the body. The lower limb is spared because its motor and sensory representation is located in the superolateral of frontal and parietal lobes which are supplied by the ACA. Because the right or non-dominant hemisphere is affected, our patient does not have any form of aphasia.
→ Patients with MCA blockage (choice A) usually present with symptoms and signs of blockage of its superior division (choice B), inferior division (choice C) and lenticulostriate division (choice D). Thus, these patients are expected to present with left sided weakness and hemianesthesia affecting the face, arm, and leg. Because the non-dominant right hemisphere is affect, hemi-neglect, astereognosis and anosognosia, hemianopsia rather than aphasia are also present.
→ Patients with inferior division of right middle cerebral artery (MCA) blockage (choice C) usually present with left sided homonymous hemianopsia because this artery supplies the parts of optic pathway that pass through the temporal lobe. Because the non-dominant hemisphere is affected, hemi-neglect, astereognosis, and anosognosia rather than aphasia accompanies the hemianopsia.
→ Patients with blockage of lenticulostriate branches of the right MCA (choice D) usually present with left sided hemianesthesia and hemiparesis of the leg, arm, and face. The lenticulostriate branches of the right MCA together with anterior choroidal artery supply the posterior limb of the internal capsule on the right where the motor and sensory fibers pass between the cortex and brain stem. Because motor and sensory fibers for both upper and lower parts of the body come close to each other, both of these parts of the body are affected.
→ Patients with right anterior cerebral artery (ACA) blockage (choice E) usually present with left sided hemianesthesia and hemiparesis of the leg. The right ACA supplies the superolateral portions of the right frontal and parietal lobes, which due homunculus topography, contains the motor and sensory areas of the lower part of the body (leg). The arms and the face are usually not affected by blockage of the ACA because cortical areas representing these parts of the body are located along the lateral surface of the cerebral hemisphere and are supplied by superior division of MCA.
Key point:
Weakness and anesthesia of the left arm and left half of the face and sparing of the lower leg is most likely caused by blockage in the territory of the middle cerebral artery (MCA) other than the lenticulostriate division. Absence of hemi neglect and hemianopsia exclude blockage of the inferior division and favours blockage of the superior division of the right MCA.
A 56-year-old man, whose father died of prostate cancer, is found to have on digital rectal exam (DRE) a small nodule on the right lobe of his prostate. His PSA level is 2.2.
The appropriate management is:
Correct Answer D:
An annual digital rectal examination (DRE) beginning at age 50 year for the early detection of both rectal and prostate cancer is, recommended. PSA testing screening guidelines are still not established - insufficient evidence (in quality or quantity) to make a recommendation; however, other factors may influence decision making (done if required by patient). A PSA level of less than 4 ng/ml is normal. A level between 4 and 10 is the ‘grey’ zone and above 10 is suspicious for malignancy.
During a DRE, a nodule must be taken seriously since 50% of prostate nodules are cancerous. Especially in this patient who has positive family history. The presence or absence of cancer in a prostate nodule is ordinarily determined by the results of a transrectal needle aspiration biopsy.
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