Exame Abdominal II: Percussão
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Overview
Fonte: Alexander Goldfarb, MD, Professor Assistente de Medicina, Beth Israel Deaconess Medical Center, MA
A percussão médica baseia-se na diferença de tom entre os sons provocados por toques na parede do corpo. A resposta auditiva ao toque depende da facilidade com que a parede do corpo vibra, e é influenciada por órgãos subjacentes, força do derrame e o estado da parede do corpo. Existem três sons principais de percussão médica: ressonância (ouvida sobre os pulmões), timpano (ouvido sobre as alças intestinais cheias de ar) e tédio (ouvido sobre fluido ou órgãos sólidos). O contraste entre o embotamento vs. tympany ou ressonância permite a determinação do tamanho e margens de órgãos e massas, bem como a identificação do acúmulo de fluidos e áreas de consolidação. A percussão continua sendo uma parte intrincada do diagnóstico físico desde que foi introduzida pela primeira vez há mais de 200 anos, e é especialmente útil no exame dos pulmões e abdômen.
Como parte de um exame abdominal, a percussão segue inspeção visual e auscultação. O examinador deve primeiro percuss sobre cada uma das nove regiões abdominais (região epigástrica, região hipocondríaca direita, região hipocondríaca esquerda, região umbilical, região lombar direita, região lombar esquerda, região hipogástrica, região inguinal direita e região inguinal esquerda). A ternura provocada pela percussão é anormal, e deve-se suspeitar de inflamação peritoneal. À medida que as alças intestinais cheias de ar são posicionadas na proximidade mais próxima da parede abdominal, a percussão sobre a maioria das partes da cavidade abdominal provoca um som predominantemente tirapônico. A presença de grandes áreas de tédio deve solicitar a avaliação de organomegaly, massas intra-abdominais ou fluidos.
Além de avaliar a quantidade e distribuição de gás abdominal, um exame abdominal deve incluir uma estimativa do tamanho do fígado e do baço por percussão. Como o fígado e o baço estão cobertos pela caixa torácica, o examinador deve percuss sobre o peito anterior inferior também. Normalmente, espera-se ouvir som maçante na percussão do peito anterior direito sobre o fígado, e som timpônico na percussão do peito anterior esquerdo sobre a bolha de ar gástrico e o flexão esplênico do cólon(Figura 1).
Figura 1. Notas normais de percussão sobre a região abdominal. Com exceção de uma área de tédio sobre o fígado no peito anterior inferior direito, tiranpania é o som predominante ouvido sobre a região.
Procedure
Applications and Summary
Despite rapid advances in imaging techniques, abdominal percussion remains an essential part of a physical examination. Correct percussion technique is critical for this method to be effective. The percussion strike should be kept the same over the entire abdomen. All the information obtained during the patient’s interview and full physical examination, and a good knowledge of differential diagnoses of each pathological sign is essential for proper interpretation of any findings. For example, a false increase of liver span on percussion can result from right lung consolidation and/or a pleural effusion. One should also be aware of the limitation of the method and the sensitivity of each diagnostic maneuver. While percussion is only moderately accurate in detecting hepato-and splenomegaly, abnormal findings should prompt further clinical evaluation.
Transcript
Percussion is a critical part of the abdominal examination; therefore, learning the correct technique is essential for any physician aiming to make quick, yet accurate diagnosis of gastrointestinal pathologies. As you might know, medical percussion is based on the difference in pitch between the sounds elicited by tapping on the body wall. The sounds produced during abdominal percussion can help detect pathologies like organomegaly, intra-abdominal masses, and fluid accumulation. This video will illustrate the major anatomical areas to be percussed during an abdominal exam, and the steps and findings of this procedure.
First, let’s talk about the expected abdominal percussion sounds and their interpretations. As the air-filled bowel loops are positioned in the closest proximity to the abdominal wall, percussion over most parts of the abdominal cavity elicits a predominantly tympanic sound… Notice that this sound is relatively long, high pitched, and loud.
Percussion over dense organ tissues, like the spleen or the liver, produces a dull sound… Therefore, the contrast between dullness versus tympany allows for determination of the margins of these organs and thus help in detection of conditions like hepatomegaly or splenomegaly. Dull sounds are also produced on percussing areas filled with fluid and feces. Therefore, by percussing one can predict the cause of protuberant abdomen, which helps in diagnosis of conditions like ascites.
With this background in mind, let’s review a detailed step-wise procedure for abdominal percussion. Explain the procedure to the patient and obtain their consent before starting with the exam. Drape the patient appropriately to expose the torso area and perform light percussion over each of the nine abdominal regions.
Listen to the intensity, pitch, and duration of the percussion note. Normally, tympanic sound produced by air in the bowel loops will be heard… As you percuss, watch the patient’s face for any signs of discomfort. Ask the patient if they are experiencing any tenderness. Tenderness on percussion is abnormal and can indicate peritoneal inflammation.
After abdominal area, percuss the lower anterior chest, above the costal margins. Dull sound on the right, over the liver is expected… On the left, one should hear tympany over the gastric air bubble and the splenic flexure of the colon… Following that, move to the area of pubic symphysis. Again, this should yield a tympanic sound…dullness indicates enlarged uterus or distended bladder.
Next step is to determine the liver span. Start by locating the right midclavicular line. Starting in the area of tympany below the umbilicus, lightly percuss in the right midclavicular line moving upwards… Make a mark where the tympany changes to dullness with a skin pencil. This is the lower border of the liver. Then, starting at the nipple line, again percuss in the right midclavicular line moving downwards. Note the point where the resonant sound changes to dullness…and mark it with a skin pencil. This is the upper border of the liver. Measure the distance between upper and lower border in centimeters. The liver span is normally 6-12 cm.
Following the liver span measurement, percuss to detect splenomegaly. The two maneuvers for this include Percussion of the Traube’s space and the Castell’s method. For percussion of the Traube’s space, make sure that the patient’s left arm is slightly abducted, and percuss from the medial to lateral border of this area. Overall dullness on percussion, or reduction of the area of tympany can indicate spleen enlargement. For the Castell’s method, percuss in the anterior axillary line in the lower intercostal space. Ask the patient to take a deep breath and percuss again. Normally, the percussion tone is tympanic on both inspiration and expiration. If the percussion note is dull, or becomes dull on inspiration, splenomegaly should be suspected.
Lastly, percussion is helpful to detect the cause of a protuberant abdomen. If the patient has a protuberant abdomen, percuss from the umbilicus in a lateral direction and with the skin pencil make a mark of the point where the tympanic sound changes to dullness. Then, ask the patient to roll on their side and repeat the percussion starting from the top and make a second mark when the tympanic sound changes to dull. If abdominal fluid were present, the level of dullness on the side would shift upwards toward the umbilicus, compared to the level of dullness in supine position.
You’ve just watched JoVE’s video on percussion to be performed during an abdominal exam. You should now know the important abdominal percussion steps and understand differential diagnoses that can be performed by proper interpretation of percussion findings. As always, thanks for watching!