Complications of Nephrotic Syndrome

Hyperlipidemia
The occurrence of hyperlipidemia may be considered a typical feature of the nephrotic syndrome, rather than a mere complication. It is related to the hypoproteinemia and low serum oncotic pressure of nephrotic syndrome, which then leads to reactive hepatic protein synthesis, including of lipoproteins.
Some of the elevated serum lipoproteins are filtered at the glomerulus, leading to lipiduria and the classical findings of oval fat bodies and fatty casts in the urine sediment.

Atherosclerotic vascular disease appears to occur in greater frequency in subjects with nephrotic syndrome than in healthy subjects of the same age. The frequency and extent of coronary artery disease stenoses were greater in patients with nephrotic syndrome.

Complication of edema:

Pulmonary edema causing hypoxia and dyspnea and congestive heart failure

Other complications:

Acute renal failure: due to hypovolemia. Despite the excess of fluid in the tissues, there is less fluid in the vasculature.
Decreased blood flow to the kidneys causes them to shutdown. Thus it is a tricky task to get rid of excess fluid in the body while maintaining circulatory euvolemia.
Hypovolemia is generally observed only when the patient's serum albumin level is less than 1.5 g/dL. Symptoms include vomiting, abdominal pain, and diarrhea.
The signs include cold hands and feet, delayed capillary filling, oliguria, and tachycardia. Hypotension is a late feature.

Thrombotic episodes: leakage of anti-thrombin 3 which prevents thrombosis. oral anticoagulants can treat this (but not heparin as heparin acts via anti-thrombin 3)

Infections:due to leakage of immunoglobulins, encapsulated bacteria such as Haemophilus influenzae and Streptococcus pneumoniae can cause infection.

Growth retardation: does not occur in MCNS.It occurs in cases of relapses or resistance to therapy. Causes of growth retardation are protein deficiency from the loss of protein in urine, anorexia (reduced protein intake), and steroid therapy (catabolism).

Vitamin D deficiency can occur. Thyroxine is reduced due to decreased thyroid binding globulin. Maybe also a reduced ability of the kidneys to convert calcidiol to its active form.

Hypocalcemia can occur as a result of Nephrotic Syndrome. Hypocalcemia is common in the nephrotic syndrome, but rather than being a true hypocalcemia, it is usually caused by a low serum albumin level.
Nonetheless, low bone density and abnormal bone histology are reported in association with nephrotic syndrome.
This could be caused by urinary losses of vitamin D – binding proteins, with consequent hypovitaminosis D and, as a result, reduced intestinal calcium absorption.

Microcytic hypochromic anaemia is typical. It is iron-therapy resistant.