Pneumopericardium is a medical condition where air enters the pericardial cavity. This condition has been recognized in preterm neonates, in which it is associated with severe lung pathology, after vigorous resuscitation, or in the presence of assisted ventilation. This is a serious complication, which if untreated may lead to cardiac tamponade and death. Pneumomediastinum, which is the presence of air in the mediastinum, may mimic and also coexist with pneumopericardium. It can be congenital, or introduced by a wound. Presentation
The symptomatic patient may present with dyspnea, cyanosis, chest pain, pulsus paradoxus, bradycardia or tachycardia. Pathophysiology
The mechanism responsible for pneumopericardium is the ‘Macklin effect’ – There is initially an increased pressure gradient between the alveoli and the interstitial space. Increased pressure leads to alveolar rupture, resulting in air getting through to the pericapillary interstitial pulmonary space. This space is continuous with the peribronchial and pulmonary perivascular sheaths. From here, the air tracks to the hilum of the lung and then to the mediastinum. In case of a pericardial tear, this air enters the pericardial cavity and pneumopericardium develops. The condition may remain asymptomatic or may progress to life-threatening conditions like tension pneumopericardium or cardiac tamponade. Diagnosis
On physical examination, the patient may have the classic “Beck’s triad” – hypotension, raised JVP and distant heart sounds, when complicated by cardiac tamponade. Extension of the mediastinal air to the subcutaneous tissues via the fascial planes may lead to subcutaneous emphysema.
Finally, after autoamputation, the base of the proximal phalanx remains. Radiological examination allows early diagnosis and staging of ainhum. Early diagnosis is crucial to prevent amputation. Doppler shows decreased blood flow in posterior tibial artery. Differential diagnosis
Ainhum is an acquired and progressive condition, and thus differs from congenital annular constrictions. Ainhum has been much confused with similar constrictions caused by other diseases such as leprosy, diabetic gangrene, syringomyelia, scleroderma or Vohwinkel syndrome. In this case, it is called pseudo-ainhum, treatable with minor surgery or intralesional corticosteroids, as with ainhum. It has even been seen in psoriasis or it is acquired by the wrapping toes, penis or nipple with hairs, threads or fibers. Oral retinoids, such as tretinoin, and antifibrotic agents like tranilast have been tested for pseudo-ainhum. Impending amputation in Vohwinkel syndrome can sometimes be aborted by therapy with oral etretinate. It is rarely seen in the United States but often discussed in the international medical literature. Prevention
Wearing shoes to protect barefoot trauma has shown decrease in incidence in ainhum. Congenital pseudoainhum cannot be prevented and can lead to serious birth defects. Treatment
Incisions across the groove turned out to be ineffective. Excision of the groove followed by z-plasty could relieve pain and prevent autoamputation in Grade I and Grade II lesions. Grade III lesions are treated with disarticulating the metatarsophalangeal joint. This also relieves pain, and all patients have a useful and stable foot. Intralesional injection of corticosteroids is also helpful. Epidemiology
Ainhum predominantly affects black people, living in West Africa, South America and India.