The term “hydro” means water; “pikos”, from pike or pickerel fish, refers to the appearance of the swollen cell in which it appears that there are small holes on its surface. The term was first used by William Harvey in 1628 when he described this condition in his book De Motu Cordis et Sanguinis In Animalibus. He wrote:
“…the blood vessels become so distended with blood that they appear like little fishes swimming through their own juices.”
What are Hydropic Changes
Hydropic changes can occur in any organ system but most commonly affect kidneys, liver, heart, lungs, brain, spleen, pancreas, adrenal glands, bone marrow and lymph nodes. They may also be present in other organs such as thyroid gland, salivary glands, stomach, ovaries, testes, prostate, epididymis, seminal vesicles, fallopian tubes, uterus, placenta, umbilical cord and skin. Hydropic changes do not always indicate disease. However, if associated with fever, weight loss, fatigue, abdominal pain, vomiting, diarrhea, jaundice, malaise, headache, confusion, seizures, coma, respiratory distress, shock or renal failure then these symptoms should suggest the diagnosis of systemic illness.
Hydropic changes usually develop within 24 hours after injury. During this time period, the affected tissue swells because of increased capillary permeability. This results in leakage of plasma into extravascular spaces leading to interstitial oedema and ultimately to necrosis. If the lesion does not resolve spontaneously, death occurs within 2-3 days.
Causes include trauma, surgery, infection, toxic agents, radiation exposure, burns, malignancy, drugs, toxins, metabolic disorders, endocrine disturbances, autoimmune diseases, genetic defects, nutritional deficiencies, pregnancy/postpartum state, and lactational amenorrhea.
In some cases, the cause cannot be determined. These patients have idiopathic hydrops.
In many instances, the underlying disorder causing the hydropic process remains undiagnosed even though clinical manifestations have been resolved.
There are two types of hydropic processes – primary and secondary. Primary hydropic conditions result from congenital abnormalities, whereas secondary hydropic conditions arise following damage to normal tissues. Congenital causes include Beckwith–Wiedemann syndrome, Noonan’s syndrome, Turner’s syndrome, and trisomy 13, 18, 21. Secondary causes include neoplasms, infections, immune complex mediated diseases, drug toxicity, and vascular insults including thrombosis, embolism, vasculitis, infarction, arterial occlusion, venous stasis, hypoperfusion, and haemorrhage.
Primary hydropic conditions are characterized by marked enlargement of all body fluids and tissues without evidence of inflammation. A variety of different pathologic mechanisms underlie the development of hydropic lesions.
How do you diagnose it?
Diagnosis can be made by clinical examination alone if there is no history of trauma. If there has been a recent injury then X-ray may show evidence of fracture. In case of suspected infection, blood tests will reveal elevated white cell count. Ultrasound scan shows increased echogenicity of soft tissues. CT scans show areas of low density within muscles.
The treatment depends on the severity of condition. The patient needs close monitoring for signs of complications like septicemia, pulmonary insufficiency, cardiac decompensation, electrolyte imbalance, etc.