Hoover's Sign - What is the underlying cause?

What is the cause of Hoover's Sign (COPD). What causes it to remain flat and not dome-shaped?

Cheers

From Wikipedia,

Hoover’s sign refers to one of two signs named for Charles Franklin Hoover.

Charles Franklin Hoover (1865–1927) was an American physician born in Cleveland, Ohio, who read medicine at Harvard. He worked in Vienna under Neusser, and in Strasburg with F Kraus before returning to Cleveland. He was appointed Professor of Medicine in 1907. His main interests were in diseases of the diaphragm, lungs, and liver.

Leg paresis

One is a maneuver aimed to separate organic from non-organic paresis of the leg. The sign relies on the principle of synergistic contraction. Involuntary extension of the "paralyzed" leg occurs when flexing the contralateral leg against resistance. It has been neglected, although it is a useful clinical test. Essentially, you hold your hand under the contralateral heel and ask the patient to extend the leg off the bed. If you feel pressure from the contralateral heel, the weakness is likely organic. If no pressure is felt, the patient is likely suffering from non-organic limb weakness.

Strong hip muscles can make the test difficult to interpret.

Efforts have been made to use the theory behind the sign to report a quantitative result.

Pulmonary

Another Hoover’s sign is inward movement of the lower rib cage during inspiration, implying a flat, but functioning, diaphragm, often associated with COPD.

This is an indication of a change in the contour of the diaphragm as a result of intrathoracic conditions in which movement of the costal margins of the diaphragm changes during respiration.

Also an Abstract from:

The Hoover's Sign of Pulmonary Disease: Molecular Basis and Clinical Relevance
Chambless R Johnston, Narayanaswamy Krishnaswamy1 email and Guha Krishnaswamy
Clinical and Molecular Allergy 2008, 6:8 doi:10.1186/1476-7961-6-8

In the 1920's, Hoover described a sign that could be considered a marker of severe airway obstruction. While readily recognizable at the bedside, it may easily be missed on a cursory physical examination. Hoover's sign refers to the inspiratory retraction of the lower intercostal spaces that occurs with obstructive airway disease. It results from alteration in dynamics of diaphragmatic contraction due to hyperinflation, resulting in traction on the rib margins by the flattened diaphragm. The sign is reported to have a sensitivity of 58% and specificity of 86% for detection of airway obstruction. Seen in up to 70% of patients with severe obstruction, this sign is associated with a patient's body mass index, severity of dyspnea and frequency of exacerbations. Hence the presence of the Hoover's sign may provide valuable prognostic information in patients with airway obstruction, and can serve to complement other clinical or functional tests. We present a clinical and molecular review of the Hoover's sign and explain how it could be utilized in the bedside and emergent management of airway disease.

Thanks Physiobob - I saw Hoover's sign documented by a neurologist the other day but hadn't gotten around to looking it up (in a patient with suspected conversion disorder).

Most helpful!

Hi,

Just wondering what you mean by optimising the use of Hoovers sign at the bedside. Its something that I ahve never heard of before and would like to know more as I have just started my first junior rotation on respirtory

Thanx x