Lesson 1, Topic 1
In Progress

Signs and Symptoms

Since decompression sickness can interfere with the function of a large number of tissues of the body, the amount of potential signs and symptoms is vast.

In the past these symptoms were grouped according to the anatomical location and presumed mechanism of the disease: type I (mild) and type II (severe). These terms are still used today, but their small value is widely recognized, not only because symptoms of the two groups can coexist, but also because a type I accident can evolve into a type II accident.

Thus, the symptomatology of this accident is presented according to the clinical evolution and its manifestations . Evolution can be progressive, static, spontaneously improve, or reappear.

Manifestations of decompression sickness may occur alone or combined .


  • Headaches;
  • Exaggerated fatigue;
  • Nausea and vomiting;
  • General malaise.


  • Redness;
  • Bumps.

The redness dispersed throughout the body, more frequent on the shoulders and trunk, should not be related to allergic reactions to any marine, animal or vegetable being.


Joint pain (bend) is probably the most frequent manifestation of decompression sickness. It can also start during the climb or after the immersion is finished, mainly affecting the joints most used during the dive. It consists of a gradual installation pain, difficult to locate, which often disappears spontaneously, being often ignored by the diver.

If the pain increases, its location is more accurate and is described as a weight or a sharp and perforating pain, similar to a toothache.

Sometimes the diver finds a position where the joint becomes less painful. If located in a lower limbs joint, body weight may not be tolerated by that joint. Classic inflammatory signs, such as red, warm, and swollen skin, are usually absent.


The involvement of the nervous system can be subtle or multifocal, leading to a wide variety of manifestations, ranging from changes in mood and personality, to difficulty in speaking, through memory loss, uncoordination of movements and tingling in the upper limbs. Changes in the organs of the senses, such as misty or tunnel vision, tinnitus, sudden deafness and vertigo are also possible. In the most severe cases seizures, loss of consciousness and death may occur.

If the spinal cord is involved, tingling may appear in the legs and loss of sensitivity until the complete inability to feel them (paraparesis) and to move them (paraplegia). It may also occur that it is impossible to urinate and defecate.

Decompression sickness may manifest immediately after diving, or even in water, if the cause is omission of decompression stops or an excessively rapid rise.

Special attention should be paid to manifestations of excessive fatigue when efforts have not been expended during diving, as it may be a harbinger of a neurological accident.

About 90% of accidents occur in the first six hours and more than 50% in the first hour. The remaining 10% manifest after six o’clock. If a diver is asymptomatic more than 48 hours after the water comes out, any symptom that arises after this period, most likely does not relate to decompression sickness.


The first aid consists, in the case of conscious divers, in administering many fluids orally (water), 100% oxygen with a minimum output of 15litre/min, keeping it comfortable, followed by its evacuation in a lying position, to a Hyperbaric Unit.

Unconscious divers should be approached according to the procedures recommended in Basic Life Support and transported in a safety lateral position breathing 100% oxygen.

Definitive treatment consists of immediate recompression in Hyperbaric Chamber followed by gradual decompression according to its own tables.

Any diver who is supposed to be the victim of a decompression accident should be taken to a hyperbaric unit.

All elements of the dive group, especially the companion of the injured, must be kept under medical surveillance.