Livedo Racemosa – The Pathophysiology of Decompression-Associated Cutis Marmorata and Right/Left Shunt

Abstract

Decompression sickness and arterial gas embolism, collectively known as decompression illness (DCI), are serious medical conditions that can result from compressed gas diving. DCI can present with a wide range of physiologic and neurologic symptoms. In diving medicine, skin manifestations are usually described in general as cutis marmorata (CM). Mainly in the Anglo-American literature the terms cutis marmorata, livedo reticularis (LR), and livedo racemosa (LRC) are used interchangeably but actually describe pathophysiologically different phenomena. CM is a synonym for LR, which is a physiological and benign, livid circular discoloration with a netlike, symmetric, reversible, and uniform pattern. The decompression-associated skin discolorations, however, correspond to the pathological, irregular, broken netlike pattern of LRC. Unlike in diving medicine, in clinical medicine/dermatology the pathology of livedo racemosa is well described as a thrombotic/embolic occlusion of arteries. This concept of arterial occlusion suggests that the decompression-associated livedo racemosa may be also caused by arterial gas embolism. Recent studies have shown a high correlation of cardiac right/left (R/L) shunts with arterial gas embolism and skin bends in divers with unexplained DCI. To further investigate this hypothesis, a retrospective analysis was undertaken in a population of Austrian, Swiss, and German divers. The R/L shunt screening results of 18 divers who suffered from an unexplained decompression illness (DCI) and presented with livedo racemosa were retrospectively analyzed. All of the divers were diagnosed with a R/L shunt, 83% with a cardiac shunt [patent foramen ovale (PFO)/atrium septum defect (ASD)], and 17% with a non-cardiac shunt. We therefore not only confirm this hypothesis but when using appropriate echocardiographic techniques even found a 100% match between skin lesions and R/L shunt. In conclusion, in diving medicine the term cutis marmorata/livedo reticularis is used incorrectly for describing the actual pathology of livedo racemosa. Moreover, this pathology could be a good explanation for the high correlation of livedo racemosa with cardiac and non-cardiac right/left shunts in divers without omission of decompression procedures.

Livedo racemosa, a cutaneous sign of decompression sickness

“…5 A retrospective case-control study showed that 18 divers who had livedo racemosa in the context of an undeserved DCS all had a right/left shunt, 83% of which was an intracardiac shunt. 6 Moreover, PFO closure is associated with a decrease in DCS. 7 Though our medical center does not propose PFO closure for recreational diving, international consensus recommends, in patients who experimented DCS related to a PFO, either to cease diving, to dive more conservatively to reduce the risk of DCS, or to close the PFO.…”

The management of patent foramen ovale in divers: where do we stand?

“…Therefore, it has a pathognomonic role when it appears after diving. 15 Several risk factors have been associated with the development of DCI. Males are considered more prone than females.…”

Inner Ear Decompression Sickness (Iedcs) in Divers

“…In addition to these factors, the report also indicates the existence of an IEDCS relationship with persistent oval foramen (PFO), a type of right-to-left shunt (RLS) (Hartig et al, 2020;Mitchell & Doolette, 2015). RLS allows blood to pass through the pulmonary system.…”

“…RLS allows blood to pass through the pulmonary system. In other words, the gas bubbles that form in the venous circulation are not excreted by the lungs and can enter the arterial circulation or rather referred to as arterial gas embolism (AGE) (Gempp & Louge, 2013a;Hartig et al, 2020). One study found in 77% of IEDCS cases, large RLS was detected with greater right-side lateralization (80%).…”