In nephrology

Nephrology

Nephrology is a branch of internal medicine and pediatrics dealing with the study of the function and diseases of the kidney.-Scope of the specialty:...

, dialysis disequilibrium syndrome

Syndrome

In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...

, commonly abbreviated DDS, is the occurrence of neurologic signs and symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s, attributed to cerebral edema

Cerebral edema

Cerebral edema or cerebral œdema is an excess accumulation of water in the intracellular or extracellular spaces of the brain.-Vasogenic:Due to a breakdown of tight endothelial junctions which make up the blood-brain barrier...

, during or following shortly after intermittent hemodialysis

Hemodialysis

In medicine, hemodialysis is a method for removing waste products such as creatinine and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...

.

Classically, DDS arises in individuals starting hemodialysis due to chronic renal failure

Chronic renal failure

Chronic kidney disease , also known as chronic renal disease, is a progressive loss in renal function over a period of months or years. The symptoms of worsening kidney function are unspecific, and might include feeling generally unwell and experiencing a reduced appetite...

 and is associated, in particular, with "aggressive" (high solute removal) dialysis. However, it may also arise in fast onset, i.e. acute, renal failure

Acute renal failure

Acute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...

 in certain conditions.

Etiology

The cause of DDS is currently not well understood.

There are two theories

Theory

The English word theory was derived from a technical term in Ancient Greek philosophy. The word theoria, , meant "a looking at, viewing, beholding", and referring to contemplation or speculation, as opposed to action...

 to explain it; the first theory postulates that urea

Urea

Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....

 transport from the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

s is slowed in chronic renal failure, leading to a large urea concentration gradient, which resulting in reverse osmosis

Reverse osmosis

Reverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...

. The second theory postulates that organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s are increased in uremia

Uremia

Uremia or uraemia is a term used to loosely describe the illness accompanying kidney failure , in particular the nitrogenous waste products associated with the failure of this organ....

 to protect the brain and result in injury by, like in the first theory, reverse osmosis

Osmosis

Osmosis is the movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides...

.

Diagnosis

Clinical signs of cerebral edema, such as focal neurological deficits, papilledema

Papilledema

Papilledema is optic disc swelling that is caused by increased intracranial pressure. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare....

 and decreased level of consciousness

Consciousness

Consciousness is a term that refers to the relationship between the mind and the world with which it interacts. It has been defined as: subjectivity, awareness, the ability to experience or to feel, wakefulness, having a sense of selfhood, and the executive control system of the mind...

, if temporally associated with recent hemodialysis, suggest the diagnosis. A computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

 of the head is typically done to rule-out other intracranial causes.

MRI of the head has been used in research to better understand DDS.

Treatment

Avoidance is the primary treatment.

DDS is a reason why hemodialysis initiation is usually done gradually, i.e. it is a reason the first few dialysis sessions are shorter than is typical in an end-stage renal disease patient.

External links

• Dialysis disequilibrium syndrome - kidneydoctor.com.