From the Guidelines
Hoover's sign occurs in subphrenic abscess due to diaphragmatic irritation from the collection of pus between the diaphragm and adjacent organs, leading to reflex spasm of the diaphragm and restricted movement during respiration. This irritation causes the affected hemidiaphragm to fail to descend normally when a patient takes a deep breath, resulting in decreased or absent movement of the lower chest wall on the affected side. The pathophysiology involves local inflammation from the abscess causing pain and protective muscle spasm, which alters normal respiratory mechanics.
The clinical presentation of subphrenic abscess can be varied, but typical symptoms include lumbar pain and fever, with many patients presenting with costovertebral angle tenderness 1. However, the presence of Hoover's sign is a significant indicator of diaphragmatic involvement. Recognizing this sign is crucial for early diagnosis of subphrenic abscess, which typically requires drainage and appropriate antibiotic therapy targeting the causative organisms, usually a mixture of aerobic and anaerobic bacteria from the gastrointestinal tract.
Some key points to consider in the management of subphrenic abscess include:
- The use of CT imaging for diagnosis and management 1
- The decision to opt for drainage of the abscess, which is often influenced by the size of the abscess 1
- The importance of specimens obtained at drainage being methodically investigated for potential pathogens 1
- The consideration of surgical consultation for evaluation of long-term management of underlying pulmonary anomalies or lesions 1
In terms of treatment, while there is insufficient quality of evidence to enable a clear recommendation 1, the general approach involves medical therapy, percutaneous drainage, or surgery for refractory cases. The most appropriate treatment should be guided by the size of the abscess, the presence of any underlying conditions, and the patient's overall clinical presentation.
From the Research
Hoover's Sign in Subphrenic Abscess
- Hoover's sign is typically associated with obstructive airway disease, characterized by the inspiratory retraction of the lower intercostal spaces 2.
- However, in the context of subphrenic abscess, Hoover's sign may occur due to the proximity of the abscess to the diaphragm, which can lead to altered dynamics of diaphragmatic contraction and subsequent traction on the rib margins.
- A study on subphrenic abscess presenting with pulmonary symptoms suggests that the abscess can cause respiratory complaints due to its location adjacent to the diaphragm 3.
- The exact mechanism of Hoover's sign in subphrenic abscess is not clearly established, but it may be related to the increased pressure and inflammation in the thoracoabdominal region, which can affect diaphragmatic function.
- It is essential to consider the clinical presentation and diagnostic findings of subphrenic abscess, including roentgen findings such as elevation and restriction of motion of the diaphragm, pleural reaction, and segmental atelectasis or pneumonitis at the lung base 4.
Clinical Relevance
- The presence of Hoover's sign in subphrenic abscess may indicate severe airway obstruction or significant diaphragmatic involvement, which can have implications for patient management and prognosis 2, 3.
- A comprehensive clinical evaluation, including physical examination, imaging studies, and laboratory tests, is necessary to diagnose and manage subphrenic abscess effectively 5, 4.