Elevated Diaphragm

Questions

• 1.

  Which one the following diagnoses is most likely in the case illustrated in Fig. 6.1 ?

  • a.

    Hepatomegaly.

  • b.

    Interposition of the colon.

  • c.

    Right upper lobe atelectasis.

  • d.

    Phrenic nerve paralysis.

  • e.

    Right upper lobe pneumonia.

  

• 2.

  Which of the following is least likely to be associated with pleural effusion?

  • a.

    Primary lung tumor.

  • b.

    Interposition of colon.

  • c.

    Subphrenic abscess.

  • d.

    Echinococcal cyst.

  • e.

    Metastasis.

• 3.

  Which of the following is not true of phrenic nerve paralysis?

  • a.

    Results in complete loss of motion of the diaphragm at fluoroscopy.

  • b.

    May be secondary to primary lung tumor in the apex.

  • c.

    May be secondary to mediastinal malignant tumor.

  • d.

    Occasionally is idiopathic.

  • e.

    Results in paradoxic motion of the diaphragm.

Discussion

Elevation of the diaphragm offers a variety of radiologic challenges ( Chart 6.1 ). When both sides of the diaphragm are symmetrically elevated, the differential is significantly different from that with unilateral elevation. The most common cause of elevation of both sides of the diaphragm is failure of the patient to inspire deeply. This is frequently voluntary, but may be an indicator of a significant pathologic process. Obesity is probably the most common abnormality resulting in low lung volume. A similar appearance may be produced by a variety of abdominal conditions, including ascites and large abdominal masses. Bilateral atelectasis may also result in the elevation of both sides of the diaphragm, but is usually identifiable by increased opacity in the lung bases. Restrictive pulmonary diseases may likewise result in elevation of both sides of the diaphragm (see Cicatrizing Atelectasis in Chapter 13 ).

Subpulmonic Pleural Effusion

Subpulmonic pleural effusion is an important cause of apparent elevation of the diaphragm. 32, 53 This is usually unilateral, but on occasion may be bilateral. The posteroanterior view may suggest this diagnosis when the diaphragm appears flat, with a lateral meniscus in the costophrenic angle ( Fig. 6.2, A ), or when the dome of the diaphragm is more lateral than normal, with an abrupt drop-off ( Fig. 6.3, A ). The lateral view may help confirm this impression by demonstrating a posterior meniscus (see Fig. 6.3, B ). The diagnosis is often confirmed with a lateral decubitus view (see Fig. 6.2, B ). Caution must be exercised in evaluating a subpulmonic pleural effusion because pleural effusions may be associated with other significant abnormalities, such as a subphrenic abscess, primary lung tumor, and liver masses (including abscesses and echinococcal cysts) that result in true elevation of the diaphragm.