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Splenomegaly: David L. Simel, MD, MHS, discusses the clinical examination for splenomegaly. Please refer to Figure 46-1 and Figure 46-2 from The Rational Clinical Examination when listening to this podcast.
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Splenomegaly: David L. Simel, MD, MHS, discusses the clinical examination for splenomegaly. Please refer to Figure 46-1 and Figure 46-2 from The Rational Clinical Examination when listening to this podcast.
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Language: EN.
Segment:0 .
>> I'm Joan Stephenson, Editor of JAMA's Medical News and Perspectives Section. Today I have the pleasure of speaking with Dr. David Simel about splenomegaly. Dr. Simel, why don't you introduce yourself to our listeners. >> Hi. I'm Dave Simel. I'm the Chief of Medicine at the Durham Veterans Administration Medical Center in Duke University, but more importantly, I'm the Editor, with Drummond Rennie, of the Rational Clinical Examination Series. >> Dr. Simel, what do we know about the prevalence of splenomegaly?
Are there important demographic characteristics? >> Well, I think first to answer that let me define what we mean by splenomegaly. The true reference standard would be a pathological specimen in which the spleen is weighed and compared to normative values, but that's not particularly helpful to us as clinicians, as there is no way for us to assess the weight of the spleen before it winds up on the pathologist's table. So the second definition of splenomegaly would be what I call scanomegaly, and that is the spleen that appears large on an imaging study in comparison to normal images.
A common reference standard would be a spleen that's more than 12 to 13 centimeters in length as measured by ultrasound, and this works as a pragmatic reference standard for enlargement. And, in fact, all of the studies published over the past 13 years or so use ultrasound as the reference standard. However, clinically we think of splenomegaly as any spleen that can be palpated. And while that works, there needs to be recognition that not every patient with a palpable spleen has a pathological condition that's resulting in the enlargement.
If you examine healthy college students, about 3% of them will have a palpable spleen, and in a Canadian study of healthy postpartum women, the spleen could be felt in 12% of those women. In general, though there's not much reason to try to palpate the spleen unless you have some reason to suspect splenomegaly, and we don't recommend searching for splenomegaly unless you have a reason to suspect it. So the population for examination would be those with suspected or proven viral illness, especially mononucleosis or HIV disease, a lymphoproliferative disorder, malignancy, cirrhosis, suspected portal hypertension, suspected or proven malaria or schistosomiasis, or connective tissue disorders associated with splenomegaly.
>> Let's say you decide to examine the patient for splenomegaly. How do you go about this? >> Well, in order to appreciate this approach, it helps to understand what happens as the spleen enlarges, and I would suggest that listeners, if they have their Rational Clinical Exam book, look at figure 46-1 as I describe it, or if you don't have the book, click on the link in the podcast description and you'll see the figure. As the spleen enlarges, it can displace the stomach, but it can't move the spine, diaphragm, or kidney.
So there's only way it can go, and what happens is that the anterior pole of the spleen follows the projection of the bony portion of the tenth rib, which directs the progressing enlargement down below the rib cage and then across the abdomen at an angle towards the right iliac fossa. So in order to detect this enlargement you first inspect the left upper quadrant. And not surprisingly, a bulging mass under the left costal margin would only result from really massive splenomegaly, so it's not seen frequently outside of perhaps endemic malaria areas.
What you then do is proceed to percussion and palpation. Now, for percussion there are several different approaches, but the most accurate may be Nixon's method, and this is illustrated in figure 46-2 of the Rational Clinical Exam text. And for this method you have to place the patient in the right lateral decubitus position, with the spleen side up, and you identify the midpoint of the left costal margin and you begin to percuss in a perpendicular line from the mid-left costal margin towards the mid-axillary line.
When dullness is heard more than 8 centimeters from the costal margin, the sign's considered positive. Now, there's another method which works almost as well, and its percussion of Traube's space, T-R-A-U-B-E, Traube's space. Traube's space is a triangular area bordered by the sixth rib superiorly, the left anterior axillary line, and inferiorly by the costal margin. So from that description, the space sits underneath the rib cage.
While you have the patient supine with their left arm sort of slightly abducted, the examiner percusses in this Traube's space during quiet breathing. And normal percussion will be resonant or tympanitic, but with splenomegaly, the percussion node across one or more rib levels would be duller during inspiration. Now, there are also two palpation methods. So there are two percussion methods and two palpation methods. For palpation, the first method has the patient in the supine position, just as they were for percussing in Traube's space.
The examiner is going to stand to the right of the patient and place their right hand below the left costal margin, and you ask the patient to take long, deep breaths. With splenomegaly the spleen tip can be felt bumping into the right hand at the end of inspiration. If the spleen is not felt, keep in mind that the direction of the splenic enlargement is going to be progressively lower towards the right iliac crest. So what you do is with each respiratory cycle move the hand down about two centimeters towards the umbilicus, and feel again at the end of inspiration.
Some examiners will choose to apply counterpressure to the flank with their left hand. Now, the second approach is called the hooking maneuver of Middleton, and in this approach the patient is laying flat and takes his or her fist and places it under their own left costovertebral angle. The examiner is going to stand to the patient's left side, instead of the right side, and they're going to curl the fingers of both hands underneath the left costal margin. With the patient then taking the same long, deep breaths, the spleen can be felt bumping into the examiner's fingers.
Now, my suggestion is that the examiners learn both palpation and both percussion measures since the findings can be subtle. >> Which findings are helpful when detecting splenomegaly? >> Well, the palpation maneuvers actually seem to be more accurate than the percussion maneuvers. The likelihood ratio for the supine one-handed approach that I described is about 8 when the spleen is felt, versus a little over 2 for dullness to percussion. Normal findings on either, though have likelihood ratios of only around .4 to .5.
>> What are the reference standard tests for splenomegaly? >> Well, because examiners frequently don't feel confident in their examination and the sensitivity is low, and because the precision, meaning the agreement between observers, is not particularly good, most clinicians who are working in low prevalence areas are going to need imaging to identify splenomegaly, and for that they'll resort to ultrasound. >> Dr. Simel, is there anything else JAMAevidence users should know about diagnosing splenomegaly? >> Yes. There is one particular population that may need special attention, and that is the athlete with suspected or proven mononucleosis.
The reason is that these patients want to quickly return to sports participation, but most sports medicine experts recommend contact restriction to avoid trauma to the abdomen when their mononucleosis is accompanied by splenomegaly. And in a study of athletes with mononucleosis, the physician could only detect splenic enlargement in 17% of the patients proven to have splenomegaly by scanning. This may be due, in part, to these athletes having well-developed abdominal musculature that makes palpation more difficult.
So certainty is going to be required for these patients, and because of the low sensitivity in these otherwise healthy patients, imaging is probably going to be needed to make sure that they don't have splenomegaly. >> Thank you, Dr. Simel, for this overview of splenomegaly. For additional information about this topic, JAMAevidence subscribers can consult the online chapter on splenomegaly in the Rational Clinical Examination.
