Knee joint pain in a deep sea diver is due to?

ANSWER: (D) Increased N,,REF: Ganong 22ed chapter 37, http://en.wikipedia.org/wiki/Decompression_sicknessRepeat from December 2010Repeat (**)Decompression Sickness:As a diver breathing 80% N2 ascends from a dive, the elevated alveolar PN2 falls. N2 diffuses from the tissues into the lungs along the partial pressure gradient. If the return to atmospheric pressure (decompression) is gradual, no harmful effects are observed; but if the ascent is rapid, N2 escapes from solution. Bubbles form in the tissues and blood, causing the symptoms of decompression sickness (the bends, caisson disease). Bubbles in the tissues cause severe pains, particularly around joints, and neurologic symptoms that include paresthesias and itchingLung damage causes air embolism and not vice versa. The problem of nitrogen narcosis can be avoided by breathing mixtures of 02 and helium, and deeper dives can be made. However, the high-pressure nervous syndrome (HPNS) develops during deep dives with such mixtures. Tremors are symptoms of high pressure Nervous syndromeSigns and symptoms of decompression sicknessDCS typeBubble locationSigns & symptoms (clinical manifestations)MusculoskeletalMostly large joints (elbows, shoulders, hip, wuists, knees, ankles)Localized deep pain, ranging from mild to excruciating. Sometimes a dull ache, but rarely a sharp pain, Active and passive motion of the joint aggravates the pain. The pain may be reduced by bending the joint to find a more comfortable position, If caused by altitude, pain can occur immediately or up to many hours later.CutaneousSkinItching, usually around the ears, face, neck, arms, and upper torso, Sensation of tiny insects crawling over the skin (formication), Mottled or marbled skin usually around the shoulders, upper chest and abdomen, with itching, Swelling of the skin, accompanied by tiny scar-like skin depressions (pitting edema)NeurologicBrainAltered sensation, tingling or numbness pareshtesias, increased sensitivity hyperesthesia, Confusion or memory loss (amnesia), Visual abnormalities, Unexplained mood or behaviour changes, Seizures, unconsciousnessNeurologicSpinal cordAscending weakness or paralysis in the legs, Girdling abdominal or chest pain, Urinary incontinence and faecal incontinenceConstitutionalWhole bodyHeadache, Unexplained fatigue, Generalised malaise, poorly localised achesAudiovestibularInner earLoss of balance, Dizziness, vertigo, nausea vomiting, Hearing lossPulmonaryLungsDry persistent cough, Burning chest pain under the sternum, aggravated by breathing, Shortness of breath