SIADH syndrome (Schwartz-Batter syndrome, inappropriate vasopressin release syndrome) is a condition in which the body produces excessive amounts of one of the hormones - vasopressin. However, not only this unit itself can be very dangerous - the SIADH team can develop, among others, in patients suffering from various neoplastic diseases. What are the symptoms of SIADH and how is it treated?

SIADH syndrome , orSchwartz-Batter syndrome(short for syndrome of inappropriate antidiuretic hormone secretion) first appeared in medical discussions in the second half of the last century. It was the Vedas that two scientists, William Schwartz and Frederic Bartter, first described this unit, which they observed in two people with lung cancer. Schwartz-Bartter syndrome is another name for the disease that derives from the names of scientists.

In Polish, the problem is also referred to asinappropriate vasopressin release syndrome . In 1967, the above-mentioned researchers developed the criteria for recognizing SIADH, which are still valid today.

SIADH team: reasons

As the name of the disease suggests, SIADH syndrome is associated with inappropriate secretion of vasopressin (an antidiuretic hormone, or ADH for short).

Vasopressin is responsible for concentrating urine, which it does by stimulating the absorption of water in the renal tubules - thanks to this hormone, increased amounts of water are transported from the tubules back into the blood.

The release of vasopressin in the body is dynamically regulated depending on the demand, but it is different even when the patient suffers from the SIADH syndrome - in this case, too much vasopressin appears in the body.

The causes of the SIADH syndrome can be really different - the most common are such abnormalities as:

  • diseases of the nervous system (e.g. infections such as HIV CNS involvement, meningitis, but also subarachnoid haemorrhage or hydrocephalus, multiple sclerosis and multi-system atrophy)
  • tumors (with increased secretionvasopressins can be related to lung cancer, pancreatic cancer, stomach cancer, bladder cancer or prostate cancer)
  • respiratory diseases (including asthma, cystic fibrosis, pneumonia or lung abscess)
  • sarcoidosis
  • right heart failure

In addition to the aforementioned diseases, the use of various medications by patients can also lead to the Schwartz-Bartter syndrome - among the examples of substances that may result in abnormal, increased levels of vasopressin, the following are listed:

  • cyclophosphamide
  • carbamazepine
  • okskarbazepina
  • valproic acid
  • serotonin reuptake inhibitors
  • amitriptyline
  • morphine
  • winkrystyna

SIADH syndrome: symptoms

The ailments that occur in people with Schwartz-Bartter syndrome result from the effects of excessive amounts of vasopressin circulating through the body. In this case, water is retained in the body, and at the same time, the excretion of sodium from it remains unchanged - eventually the patient develops hyponatremia (i.e. a decrease in blood sodium concentration). The ailments that appear then in patients are usually quite non-specific and can be:

  • irritability
  • feeling tired
  • lack of appetite
  • contractions of different muscle groups
  • feeling sick
  • vomiting
  • muscle weakness
  • apathy
  • headaches
  • muscle pains

Symptoms of SIADH can vary in intensity - in some patients the symptoms are initially mild and gradually worsen, in others the symptoms progress very rapidly.

Theoretically - taking into account the above description - one could assume that the Schwartz-Bartter syndrome is not a serious problem, but in reality it is definitely different.

In the most severe disturbances of the sodium economy, it can cause:

  • disturbance of consciousness (including coma)
  • seizures
  • respiratory arrest
  • patient's death

SIADH syndrome: possible complications

The syndrome of inappropriate vasopressin release is dangerous also because of its complications. Possible complications include cerebral edema (a risk of impaction, which may develop especially when the patient's blood sodium level drops very rapidly) and pulmonary edema of non-cardiogenic origin.

SIADH team: diagnostics

Basic research that is outsourcedwhen SIADH syndrome is suspected, there are measurements of sodium levels in the blood, plasma osmolality tests and urine sodium excretion tests. However, these are not the only analyzes that should be performed to diagnose Schwartz-Bartter syndrome - tests to assess the function of the thyroid gland, adrenal glands and kidneys are also necessary. The criteria for diagnosing SIADH also include:

  • blood sodium level below 130 mmol / l
  • low plasma osmolality ( <280 mOsm/kg)
  • urinary sodium excretion over 40 mmol / l

The occurrence of disorders with normal volemia (hypervolaemia or hypovolemia make it impossible to diagnose Schwartz-Bartter syndrome) and with normal kidney, adrenal and thyroid function (the presence of dysfunction of any of these organs also does not allow for the diagnosis of SIADH syndrome).

If a syndrome of inappropriate vasopressin release is suspected, the existence of other units in the patient, in which sodium metabolism disorders may also appear, should be ruled out. In this case, the differential diagnosis takes into account, first of all, such problems as:

  • kidney failure
  • hypopituitarism
  • adrenal insufficiency
  • hypothyroidism
  • prolonged diarrhea or vomiting

It should be emphasized here that usually patients diagnosed with SIADH syndrome are ordered many other tests - these are to determine what led to the development of excessive amounts of vasopressin in the patient.

Due to how different the causes of Schwartz-Bartter syndrome can be, it is impossible to list here all the tests that may be ordered to patients in such a situation - in some patients laboratory tests are sufficient, in others it is also necessary to perform and imaging tests or other analyzes.

SIADH team: treatment

In the treatment of SIADH syndrome, initially the most important role is played by the regulation of the sodium balance. For this purpose, patients are administered sodium chloride solutions, it is also necessary to limit fluid intake.

Although sometimes the concentration of sodium in the blood in patients is lower than the norm, it should be emphasized here that the correction of such abnormalities cannot be carried out too quickly - because when there is a rapid increase in the level of sodium in the blood, patients develop various dangerous pathologies may develop (one of them is the osmotic demyelinating syndrome).

In people with SIADH syndrome, it is necessary not only to stabilize their sodium economy, but also to try to implement the effects thatthe goal will be to eliminate the cause of the disturbances.

The simplest situation occurs when the medications taken by the patient have caused the problem - in this case it usually turns out that the modification of pharmacotherapy alone results in the disappearance of vasopressin secretion disorders and sodium metabolism disorders.

And then, when the cause of SIADH syndrome is, for example, neuroinfection or lung cancer, it becomes necessary to apply specific treatment for these individuals.

SIADH team: prognosis

The prognosis of patients with Schwart-Bartter syndrome depends on the underlying problem.

When the syndrome appeared in connection with an infection, its proper treatment may result in a complete relief of its symptoms, as is the case when the individual occurred as a side effect of the patient's medications.

The situation is different, however, when the disease results in a patient suffering from significant hyponatremia and some focal neurological symptoms develop in its course - in such patients, unfortunately, it happens that even after correcting sodium metabolism disorders, they remain certain permanent neurological deficits.

About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.

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