Family Medicine Board Review

Silicosis may be acute or chronic. There are simple and complicated subtypes of chronic silicosis. Progressive massive fibrosis and silicoproteinosis are the most severe manifestations, with increasing disability and lung function associated with progressive massive fibrosis and silicoproteinosis, potentially leading to death in a few months.

Compared with the general population, even asymptomatic persons who have been exposed to high levels of silica dust are at increased risk for developing tuberculosis.

References:

Varkey B, Varkey AB. Silicosis. Accessed May 7, 2015.

Nasrullah M, Mazurek JM, Wood JM et al. Silicosis mortality with respiratory tuberculosis in the United States, 1968-2006. Am J Epidemiol. 2011;174:839-848.

Educational Objective:

Characterize the cardiac sequelae of rheumatic fever, echocardiographic characteristics of infective endocarditis, and limitations of echocardiography as an imaging modality in this setting.

Key Point:

Worldwide, rheumatic heart disease is the most common cause of mitral stenosis.

Explanation:

The patient has a distant history of rheumatic fever due to infection with Streptococcus pyogenes, which, in one-half of cases, may cause pancarditis, with the pathology arising from inflammation of the endocardium, leading to inflamed, regurgitant valves (most commonly the mitral valve). In the situation of prolonged inflammation and/or repeated infections, the mitral valve may stiffen, thicken, and become stenotic. Worldwide, rheumatic heart disease is the most common cause of mitral stenosis. Obtaining echocardiography to evaluate the patient for infective endocarditis (IE) due to recent fever and a predisposing cardiac condition would show possible vegetations, abscess, pseudoaneurysms, or valvular perforation. The initial attachment site of vegetation is usually on the ventricular surface of the semilunar valves and on the atrial surface of the atrioventricular valves. Vegetations frequently show high-frequency flutter or oscillations and can be linear, round, irregular, or shaggy.

In one study, the sensitivity for detection of vegetation with transthoracic echocardiography was 66%, whereas the specificity was 95%. These values may be reduced in cases in which the patient has a prosthetic valve, small vegetations, or has another cardiac implantable device. Increased diagnostic utility may be achieved with transesophageal echocardiography, which has a 96% sensitivity rate (92% for prosthetic valves) and a specificity rate of 90%.

The patient in this case has evidence of IE on echocardiography (major criteria), predisposing cardiac condition (minor criteria), fever (minor criteria), and conjunctival hemorrhages (minor criteria), all of which collectively meet the requirements for a diagnosis of IE based on the modified Duke criteria. The patient should receive empiric antibiotics, possibly vancomycin and cefazolin while susceptibility results are obtained. In addition, due to the severity of this patient’s mitral stenosis, she should be anticoagulated with a vitamin K antagonist or heparin, and, if her symptoms worsen, percutaneous mitral valve balloon commissurotomy may be considered.

Echocardiographic characteristics of acute rheumatic fever include pericardial effusion, ventricular dilatation, and regurgitation; annular dilatation or rupture; and persistent let throughout systole in the case of mitral regurgitation.

References:

Bonow RO, et al. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 2011.

Nishimura, RA, Otto CM, Bonow RO, et al; ACC/AHA Task Force Members. (2014). 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines [Erratum appears in: Circulation. 2014;129(23):e650]. Circulation. 2014;129(23):2440-2492.

Ramakrishnan S. Echocardiography in acute rheumatic fever. Ann Pediatr Cardiol. 2009;2(1):61-64.

Sika-Paotonu D, et al. Acute rheumatic fever and rheumatic heart disease. In: Ferretti JJ, et al, eds. Streptococcus Pyogenes: Basic Biology to Clinical Manifestations. 2017.

Educational Objective:

The Austin Flint murmur is a classic finding of aortic regurgitation.

Key Point:

The Austin Flint murmur in aortic regurgitation is caused by vibration of the mitral valve from the regurgitant jet.

Explanation:

The Austin Flint murmur is produced in aortic regurgitation, when the regurgitant jet impinges on the mitral valve and causes it to vibrate. It is a low rumble heard during diastole at the left ventricular apex .

References:

Carabello BA. Valvular Heart Disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Saunders; 2011:453-463

Kosowsky J and Takhar S. Infective Endocarditis and Valvular Heart Disease. Rosen's Emergency Medicine, Chapter 83, 1106-1112.e1

Educational Objective:

Manage end-of-life care issues.

Key Point:

There is no evidence that artificial nutrition prolongs life or improves functional status in patients with terminal diseases.

Explanation:

No evidence suggests that artificial nutrition could prolong her life or improve her functional status. Most patients with end-stage illness experience anorexia, fatigue, and weight loss. Family members often express concern that their loved one is dehydrated or malnourished and that this may lead to an expeditious and unpleasant death. Studies on this issue have not shown any benefit from duration of survival or a functional status standpoint. The benefit of intravenous hydration in patients who are terminally ill is controversial.

References:

Bruera E, Dev R. Overview of managing common non-pain symptoms in palliative care. Revised April 3, 2017. Accessed December 10, 2017.

Good P, Cavenagh J, Mather M, Ravenscroft P. Medically assisted nutrition for palliative care in adult patients. Cochrane Database Syst Rev. 2008;CD006274.

Ideal temperature for rewarming is between 38-42°C in gently circulating water (whirlpool therapy). The temperature should be maintained by a constant thermometer measurement. Higher temperatures cause the rewarming process to be much more painful.

Reference:
Danzl DF. Frostbite. In: Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed., 2009:1861-1867.