Autoantibodies produced in SLE can form immune complexes that deposit along the glomerular basement membrane and cause glomerular inflammation which leads to a nephritic syndrome. Rapidly progressive glomerulonephritis - This is a syndrome of the kidney that is characterized by rapid loss of kidney function (usually >50% decline in glomerular filtration rate (GFR) within 3 months) with glomerular crescent formation frequently seen on kidney biopsy. Without treatment, it will quickly lead to kidney failure and potentially death within months. This syndrome has numerous underlying causes that can also cause nephritic syndrome, so this may be more of an association than a cause. Infective endocarditis - Infection that affects the inner lining of the heart (endocardium) and can potentially cause a thrombus to form on one or more heart valves and, if left untreated, can cause septic emboli that can have many systemic effects, including deposition into the glomerulus, causing glomerulonephritis and nephritic syndrome. Cryoglobulinemia - Antibodies that are sensitive to the cold can become activated in cold conditions and cause an increase in blood viscosity (hyperviscosity syndrome) as well as forming immune complexes that can deposit in the small blood vessels and can cause nephritic syndrome when this occurs in the kidneys. Membranoproliferative glomerulonephritis (MPGN) - Another type of glomerulonephritis that is caused primarily by immune complex deposition in the glomerular mesangium and glomerular basement membrane thickening, which activates the complement cascade and damages the glomerulus. This damage leads to inflammation in the glomerulus and can present with a nephritic syndrome.
Functional constipation, known as chronic idiopathic constipation (CIC), is constipation that does not have a physical (anatomical) or physiological (hormonal or other body chemistry) cause. It may have a neurological, psychological or psychosomatic cause. A person with functional constipation may be healthy, yet has difficulty defecating. Symptoms and diagnosis
Chronic idiopathic constipation is similar to constipation-predominant irritable bowel syndrome (IBS-C); however, people with CIC do not have other symptoms of IBS, such as abdominal pain. Diagnosing CIC can be difficult as other syndromes must be ruled out as there is no physiological cause for CIC. Doctors will typically look for other symptoms, such as blood in stool, weight loss, low blood count, or other symptoms. To be considered functional constipation, symptoms must be present at least a fourth of the time. Possible causes are:

Anismus
Descending perineum syndrome
Other inability or unwillingness to control the external anal sphincter, which normally is under voluntary control
A poor diet
An unwillingness to defecate
Nervous reactions, including prolonged and/or chronic stress and anxiety, that close the internal anal sphincter, a muscle that is not under voluntary control
Deeper psychosomatic disorders which sometimes affect digestion and the absorption of water in the colonThere is also possibility of presentation with other comorbid symptoms such as headache, especially in children. Treatment
Treatment options appear similar and include prucalopride, lubiprostone, linaclotide, tegaserod, velusetrag, elobixibat, bisacodyl, sodium picosulphate, and most recently, plecanatide.