In carriers and heterozygotes, encephalopathy can develop in pregnancy or the puerperium. Cases have been described in carbamoyl phosphate synthetase 1, argino-succinate synthetase and ornithine carbamoyltransferase deficiency. Anti-NMDA receptor encephalitis
The most recent form of organic childbearing psychosis to be described is encephalitis associated with antibodies to the NMDA receptor; these women often have ovarian teratomas. A Japanese review found ten reported during pregnancy and five after delivery. Other organic psychoses with a specific link to childbearing
Sydenhams chorea, of which chorea gravidarum is a severe variant, has a number of psychiatric complications, which include psychosis. This usually develops during pregnancy, and occasionally after the birth or abortion. Its symptoms include severe hypnagogic hallucinations (hypnagogia), possibly the result of the extreme sleep disorder. This form of chorea was caused by streptococcal infections, which at present respond to antibiotics; it still occurs as a result of systemic lupus or anti-phospholipid syndromes. Only about 50 chorea psychoses have been reported, and only one this century; but it could return if the streptococcus escapes control. Alcohol withdrawal states (delirium tremens) occur in addicts whose intake has been interrupted by trauma or surgery; this can happen after childbirth. Postpartum confusional states have also been reported during withdrawal from opium and barbiturates.
In the rare event of misdiagnosis when another condition is causing the symptoms, the initial management – ascending closer to the surface – is still essential. Prevention
The most straightforward way to avoid nitrogen narcosis is for a diver to limit the depth of dives. The other main preventive measure is properly informed selection/choice of which gas to use for the particular dive under consideration. Since narcosis becomes more severe as depth increases, a diver keeping to shallower depths can avoid serious narcosis. Most recreational dive schools will only certify entry level divers to depths of 18 to 20 m (60 to 70 ft), and at these depths narcosis does not present a significant risk. Further training is normally required for certification up to 30 m (100 ft) on air, and this training should include a discussion of narcosis, its effects, and management. Some diver training agencies offer specialized training to prepare recreational divers to go to depths of 40 m (130 ft), often consisting of further theory and some practice in deep dives under close supervision. Scuba organizations that train for diving beyond recreational depths, may forbid diving with gases that cause too much narcosis at depth in the average diver (such as the typical widely used nitrox mixtures suitable for most recreational diving), and strongly encourage the use of other breathing gas mixes containing helium in place of some or all of the nitrogen in air – such as trimix and heliox – because helium has no narcotic effect.