If the blood supply to a single nerve is interrupted by an embolus, the result is loss of function in the muscles supplied by that nerve; this phenomenon is called a mononeuropathy. Causes
It is relatively unusual (25% of the total number of cases) for cholesterol emboli to occur spontaneously; this usually happens in people with severe atherosclerosis of the large arteries such as the aorta. In the other 75% it is a complication of medical procedures involving the blood vessels, such as vascular surgery or angiography. In coronary catheterization, for instance, the incidence is 1.4%. Furthermore, cholesterol embolism may develop after the commencement of anticoagulants or thrombolytic medication that decrease blood clotting or dissolve blood clots, respectively. They probably lead to cholesterol emboli by removing blood clots that cover up a damaged atherosclerotic plaque; cholesterol-rich debris can then enter the bloodstream. Diagnosis
Differential diagnosis
Findings on general investigations (such as blood tests) are not specific for cholesterol embolism, which makes diagnosis difficult. The main problem is the distinction between cholesterol embolism and vasculitis (inflammation of the small blood vessels), which may cause very similar symptoms - especially the skin findings and the kidney dysfunction. Worsening kidney function after an angiogram may also be attributed to kidney damage by substances used during the procedure (contrast nephropathy).
These drugs include the typical antipsychotics: phenothiazines such as chlorpromazine (Thorazine), and butyrophenones such as haloperidol (Haldol); atypical antipsychotics such as risperidone (Risperdal) and paliperidone (Invega); gastroprokinetic drugs used to treat gastro-esophageal reflux and medication-induced nausea (such as that from chemotherapy): metoclopramide (Reglan) and domperidone; less often, alpha-methyldopa and reserpine, used to control hypertension; and TRH. The use of estrogen-containing oral contraceptives are also known to increase prolactin levels when taken in high doses >35 μg. The sleep drug ramelteon (Rozerem) also increases the risk of hyperprolactinaemia. Particularly, the dopamine antagonists metoclopramide and domperidone are both powerful prolactin stimulators and have been used to stimulate breast milk secretion for decades. However, since prolactin is antagonized by dopamine and the body depends on the two being in balance, the risk of prolactin stimulation is generally present with all drugs that deplete dopamine, either directly or as a rebound effect. Specific diseases
Prolactinoma or other tumors arising in or near the pituitary — such as those that cause acromegaly may block the flow of dopamine from the brain to the prolactin-secreting cells, likewise, division of the pituitary stalk or hypothalamic disease. Other causes include chronic kidney failure, hypothyroidism, bronchogenic carcinoma and sarcoidosis. Some women with polycystic ovary syndrome may have mildly-elevated prolactin levels.