Final answer:
The symptoms of abdominal pain, constipation, neuropathies, neuropsych disturbances, and nephropathy, especially when accompanied by urine darkening upon standing, are suggestive of porphyria, a disorder of porphyrin buildup.
Step-by-step explanation:
The symptoms described in the question are strongly suggestive of porphyria, a group of disorders caused by a buildup of natural chemicals that produce porphyrin in the body. Porphyria can cause symptoms such as abdominal pain, constipation, neuropathies, neuropsych disturbances, and nephropathy. The darkening of urine upon standing, as mentioned in the reference, is a classic sign of porphyria. Nephropathy, which includes conditions like diabetic nephropathy and glomerulonephritis, could also lead to abdominal pain and changes in urine, but these symptoms are more commonly associated with porphyria when paired with neuropsychiatric symptoms and neuropathy.
Although other conditions like appendicitis, UTI, PID, and various digestive diseases can present with some of these symptoms, none include the broad combination of symptoms such as neuropathy and neuropsychiatric disturbances together with nephropathy as typically seen in porphyria. Moreover, porphyria can present with a range of gastrointestinal and neurological symptoms that can make it challenging to diagnose.