animation of the kidney. From Wikipedia Licence:Public Domain
Introduction
Proteinuria (protein in urine) is the abnormal finding of too much proteins in the urine. In healthy persons, urine contains very little protein (about 0 to 20 mg/dL). An excess (about 150 mg to 3.5 g) is suggestive of illness. This usually leads to the urine becoming foamy, but this is not distinct to proteinuria and can be seen when there is bilirubin in urine, retrograde ejaculation and the use of some drugs.
Causes
The causes can be broadly broken down into three categories:
| Category | Explanation |
|---|---|
| 1) where there is Glomerular | This leads to leakage during filtration. |
| 2) Increased protein in serum (overflow proteinuria) | This is somewhat due to a spillage into the urine. |
| 3) Resorptive affectation of p(Fanconi syndrome) | this happens when the tubular aspects of the kidney are not taking in the protein. |
Beside those listed in the table, biological agents can also be responsible for causing proteinuria an example is Bevacizumab (Avastin). Leptin in a research has also been implicated.
leptin administration to normotensive Sprague Dawley rats during pregnancy significantly increases urinary protein excretion.
Proteinuria is of importance due to its connection with renal (kidney) disease because the kidney is involved with absorption and filtration of the protein in the blood.
it is important to note that when an individual has proteinuria there could be hypoproteinemia (reduced protein in blood) this will lead to an osmotic balance that ultimately produces oedema.
Conditions with proteinuria
Proteinuria may be a feature of the following conditions:
| Condition | Explanation |
|---|---|
| Diabetic Nephropathy | In diabetes there is are microvascular complications that lead to Glomerular changes. |
| Nephrotic syndromes (i.e. intrinsic renal failure) | In nephrotic syndromes there are histological changes due to various causes that lead to leakage of protein in urine, reduced protein in serum, oedema and also hypercholesterolemia. |
| Pre-eclampsia & Eclampsia | These are multisystemic disorders that happen to the second half of pregnancy as a result of hypertension (of speculative causes) that also cause loss of protein in urine and oedema. |
| Toxic lesions of kidneys | such as drugs that have effects on cardiovascular function, those that affect tubular functions of the kidney. |
| Amyloidosis | Amyloidosis is when an protein called amyloid accumulate in tissues and organs. This build up means there will be an overflow. |
| Collagen vascular diseases (e.g. systemic lupus erythematosus) | This is an autoimmune disorders that affects the kidneys. |
| Dehydration, Strenuous exercise, Stress and Benign orthostatic (postural) proteinuria | This is a transient for if protein urea possibly due to increased concentration of body protein. |
| Glomerular diseases, such as membranous glomerulonephritis, focal segmental glomerulonephritis, minimal change disease Focal segmental glomerulosclerosis (FSGS), Membranoproliferative glomerulonephritis, Membranous nephropathy, Minimal change disease, Sarcoidosis, Alport's syndrome (lipoid nephrosis) | Refer to nephrotic syndrome |
| IgA nephropathy (i.e. Berger's disease) ,IgM nephropathy Rheumatoid arthritis | these are all autoimmune disorders that affects the kidney causing damage to the nephrons. |
| Drugs (e.g. NSAIDs, nicotine, penicillamine, lithium carbonate, gold and other heavy metals, ACE inhibitors, antibiotics, or opiates (especially heroin) | The drugs listed in this section all have been found to be nephrotoxic. |
| Fabry's disease | this is a lysosomal storage disease |
| Infections (e.g. HIV, syphilis, hepatitis, poststreptococcal infection, urinary schistosomiasis) | the disease conditions in this section have affection in the kidney. |
| Aminoaciduria | the is due to a defective amino acid metabolism. |
| Fanconi syndrome in association with Wilson disease | this metabolic disorders leads to excretion of products of metabolism in urine. |
| Hypertensive nephrosclerosis | this is a form of hardening of the kidney later resulting in damage to the vessel of the kidney. |
| Interstitial nephritis | this inflammation o |
| Sickle cell disease | sick cell disease can lead to glomerulosclerosis leading to loss of protein. |
| Hemoglobinuria & Myoglobinuria | this means blood in urine and myoglobin in urine: given that haemoglobin in blood and myoglobin in muscle are proteins it will be dipstick positive. |
| Multiple myeloma | this is a malignant condition that leads to dead tissue accumulating in the glomeruli. This then presents with Benz Jones proteins. |
| Organ rejection | when an organ that was implanted is being acted upon by the immune system. |
| Goodpasture's syndrome Sjögren's syndrome | see autoimmune |
You can also leave other causes and the mechanism in the comment section below if you know others
Diagnosis
| * | Protein dipstick grading | * |
|---|---|---|
| Designation | Approx.amount | * |
| * | Concentration | Daily |
| Trace | 5–20 mg/dL | |
| 1+ | 30 mg/dL | Less than 0.5 g/day |
| 2+ | 100 mg/dL | 0.5–1 g/day |
| 3+ | 300 mg/dL | 1–2 g/day |
| 4+ | More than 1000 mg/dL | More than 2 g/day |
The fastest way of determining the amount of protein in urine remains the dipstick method. This method does sometimes give a false negative if the urine is dilute. The amount is subjective read off through the urine strip as trace,+1,+2,+3,or+4.
Treatment
As listed in the large table above there are many causes of proteinuria (some not mentioned) the treatment largely depends on the cause of the condition.
Reference
•https://www.mayoclinic.org/diseases-conditions/diabetic-neuropathy/symptoms-causes/syc-20371580
•https://en.m.wikipedia.org/wiki/Nephrotic_syndrome
•https://en.m.wikipedia.org/wiki/Eclampsia
•https://en.m.wikipedia.org/wiki/Nephrotoxicity
•https://en.m.wikipedia.org/wiki/Nephrotoxicity
For further details
•https://www.webmd.com/a-to-z-guides/proteinuria-protein-in-urine
•http://www.kidneyfund.org/kidney-disease/kidney-problems/protein-in-urine.html
•https://en.m.wikipedia.org/wiki/Proteinuria
•https://emedicine.medscape.com/article/238158-overview
•https://www.kidneyresearchuk.org/health-information/proteinuria
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