Today, diagnosis intends to look at some other health challenges that may look like nephrotic syndrome but are not. what is aptly described as “differential diagnosis” of nephrotic syndrome in medical parlance?
We would like to use this opportunity to talk about water in the body. This is the main solvent in which everything dilutes into. You may not believe this; but the truth is that man is water. Those who have been to a crematorium, a place where those who wish to have their bodies burnt on passing on, would have noticed that after cremation the real elemental ash collected might not be enough to fill up a beer bottle, just 18 per cent of the total body mass.
In nature, water is distributed in three main compartments in the human body. Firstly is the intracellular compartment, inside the cells, that is surrounded by covering known as plasma membrane. This is a bi-layered phospho-lipids (phosphorous and fat), in which resides the nucleus of the cell and suspended in the water are organelles (micro structures) where chemical reactions in the body take place.
The second compartment is known as the extracellular (outside the cell) and this is further subdivided into interstitial and intravascular (inside vessels) compartments. Interstitial fluid is responsible for the movement of ions, nutrients and proteins across cell membranes. It is the immediate environment of cells; a dynamic environment that is regulated by lymphatic fluid flow. In a man weighing 70kg, the interstitial fluid is approximately 10.5 litres in its total volume . It is here that when there is a challenge leading to excessive fluid accumulation in the body that oedema develops.
The second compartment of extracellular fluid is the intravascular space. The main fluid found in this compartment is blood made up of three main components; blood cells, osmotic active colloids mainly comprising of globulins (proteins) and water soluble glucose, ions etc. The volume of this compartment is regulated by the hydrostatic pressure gradients from the pumping heart, gravity and absorption by the kidneys. in a 70kg man, the average volume in this compartment is 3.5litres and above.
There is a third compartment, which actually are potential spaces. The obvious ones include the peritoneal and pleural cavities. The peritoneum is the outer covering of the contents of the abdomen often referred to visceral organs. These include the intestine, the uterus, pancreas etc. It can be likened to wrapping a delicate gift with a soft cover before packaging it. This is also applicable to the pleural space and the lungs. Fluid only accumulates here when there is a challenge. Fluid in the intestinal tract is also classified as belonging to the third space.
Water in the body is derived from two main sources; firstly from the one ingested during eating and drinking. The second source is during the breakdown of carbohydrate to produce chemical energy in the form of adenocine triphosphate (ATP).
Now speaking of conditions that may mimic nephrotic syndrome in which there is pronounced fluid retention in the interstitial space leading to oedema; what comes to mind immediately is heart failure. When both sides of the heart fail, a condition known as congestive cardiac failure, the fluid retention starts from the ankles and gradually progress to affect all parts of the body and is known as anarsaca.
What differentiates heart failure from nephrotic syndrome is that there may be enlargement of the heart known as cardiomegaly. In addition there would be other classical signs related to circulatory disturbances like engorgement of the veins of the neck often described as raised intravenous pressure. This is as a result of the inability of the failed right ventricle to pump out blood coming from the systemic circulation.
The next common condition, which can mimic nephrotic syndrome, is liver failure. chronic hepatitis is one condition that is very common in our environment. the recurrent inflammation of the liver and its healing results in scarring; a condition known as cirrhosis. This also can be caused by excessive alcohol period of time consumption over along especially if the individual is on poor diet.
In the case of liver related fluid retention, usually there would have been a history of yellowness of the sclera (white part of the eyes) known as jaundice. Those with fair skin in advanced liver disease may have prominent and dilated veins around the umbilicus; a condition known as caput medusae. There would also be derangements of other liver functions.
A class of some medications known as non-steroidal anti-inflammatory drugs (NSAID) is well known to cause fluid retention in the extremities. This is also common in prolonged use of corticosteroids and sex hormones in aggressive management of infertility related to hormonal challenges.
Malignancies or rather cancers that spread to distant organs (metastases) can also present a picture similar to nephrotic syndrome. The common sites for cancer metastases are the lungs and the liver although cancer can spread to any part of the body. These organs are rich in blood supply, nutrients and oxygen. Malignancies with secondaries in these organs have bad outlook or poor prognosis. usually the causes of fluid imbalance in these conditions are obvious.
The presence of protein in urine (proteinuria) is not always an indication that the person has nephrosis or nephrotic syndrome. The pregnant state is a very common example where the patient may also have raised blood pressure. The condition is known as pre-eclampsia and could be an obstetric emergency. The proteinuria disappears once the baby is out.
Multiple myeloma is cancer of plasma cells, which are responsible for the production of antibodies. In multiple myeloma, abnormal antibodies known as paraproteins are produced, which causes damage to the kidney. Do you still remember Bence-Jones protein proteins in our previous outing?
We will try to conclude this series in our next outing.
Haba AGPMPN Lagos!
the acronym AGPMPN means Association of General and Private Medical Practitioners of Nigeria. It is an affiliate member of the Nigerian Medical Association. Recently the election into the executive offices of the Lagos State branch of the NMA was held and concluded. The people have spoken; rightly or wrongly. Please let us allow democratic culture to flourish.
What has been very disturbing lately are the various SMS sent to members phones. Some of the words used are unprintable. Please gentlemen, this is not the best in this season of anomy. We’ve been informed that the elders have intervened. Let’s sheath our swords.