Limited case data suggest that recompression does not usually cause harm if the differential diagnosis between IEBt vs IEDCS is doubtful. Barosinusitis
The sinuses, like other air-filled cavities, are susceptible to barotrauma if their openings become obstructed. This can result in pain as well as epistaxis (nosebleed). Diagnosis is usually simple provided the history of pressure exposure is mentioned. Barosinusitis, is also called aerosinusitis, sinus squeeze or sinus barotrauma. Sinus barotrauma can be caused by external or internal overpressure. External over-pressure is called sinus squeeze by divers, while internal over-pressure is usually referred to as reverse block or reverse squeeze. Mask squeeze
If a divers mask is not equalized during descent the relative negative internal pressure can produce petechial hemorrhages in the area covered by the mask along with subconjunctival hemorrhages. Helmet squeeze
A problem mostly of historical interest, but still relevant to surface supplied divers who dive with the helmet sealed to the dry suit. If the air supply hose is ruptured near or above the surface, the pressure difference between the water around the diver and the air in the hose can be several bar. The non-return valve at the connection to the helmet will prevent backflow if it is working correctly, but if absent, as in the early days of helmet diving, or if it fails, the pressure difference will tend to squeeze the diver into the rigid helmet, which can result in severe trauma.
A variety of injuries may be present, which may include inner ear haemorrhage, intralabyrinthine membrane tear, perilymph fistula, and other pathologies.Divers who develop cochlear and/or vestibular symptoms during descent to any depth, or during shallow diving in which decompression sickness is unlikely, should be treated with bed rest with head elevation, and should avoid any activity which could cause raised cerebrospinal fluid and intralabyrinthine pressure. If there is no improvement in symptoms after 48 hours, exploratory tympanotomy may be considered to investigate possible repair of a labyrinthine window fistula. Recompression therapy is contraindicated in these cases, but is the definitive treatment for inner ear decompression sickness, making an early and accurate differential diagnosis important for deciding on appropriate treatment. IEBt in divers may be difficult to distinguish from inner ear decompression sickness (IEDCS), and as a dive profile alone cannot always eliminate either of the possibilities, the detailed dive history may be necessary to diagnose the more likely injury. It is also possible for both to occur at the same time, and IEDCS is more likely to affect the semicircular canals, causing severe vertigo, while IEBt is more likely to affect the cochlea, causing hearing loss, but these are just statistical probabilities, and in reality it can go either way or both. It is accepted practice to assume that if any symptom typical of DCS is present, that the diver has DCS and will be treated accordingly with recompression.