Fluid Excess/Intoxication

Original Editor - Jordan Benock and Riley Benock as part of the from Bellarmine University's Pathophysiology of Complex Patient Problems project. Top Contributors - Riley Benock, Lucinda hampton, Kim Jackson, Admin, Elaine Lonnemann, Jordan Benock, Wendy Walker and George Prudden

Definition/Description

Fluid excess can occur in two main ways in the body, water intoxication and edema.  

1. Water Intoxication - The result of an excess of extracellular water without having an excess of solutes.  Due to this imbalance, the extracellular fluid (ECF) becomes diluted causing water to move into cells to equalize solute concentration on each side of the cell. Hyponatremia, a potentially lethal situation, may occur if high volumes of water are consumed without solute replacement. 
2. Edema -  The excess of both solutes and water, which is also termed isotonic volume excess.  The additional fluid is retained in the extracellular compartment resulting in fluid accumulation in the interstitial spaces. 

Prevalence

Water intoxication is seen in a variety of situations, but most commonly occurs in: 

• Patients suffering from psychogenic polydipsia (compulsive water drinking) which is often associated with mental illness 
• Army recruits/members 
• Endurance athletes 

In a study by Almond et al. of the 2002 Boston Marathon it was found that: 

• 13% of 488 runners studied had hyponatremia (serum sodium concentration of 135 mEq/L or less)
• 0.6% had critical hyponatremia (serum sodium concentration of 120 mEq/L or less)

In a study by Speedy et al. of athletes who finished an ultramarathon, it was found that: 

• 18% of 330 athletes were hyponatremic
• 3.3% were classified as being severely hyponatremic

Characteristics/Clinical Presentation

Water Intoxication Clinical S&S: 

Water intoxication presents with symptoms that are largely neurologic due to the shifting of water into brain tissues and resultant dilution of sodium in the vascular space.

• Decreased mental alertness
• Sleepiness
• Anorexia
• Poor motor coordination
• Confusion

In severe imbalances:

• Convulsions
• Sudden weight gain
• Hyperventilation
• Warm, moist skin
• Signs of increased intracerebral pressure: Slow pulse; Increased SBP (more than 10 mm Hg); Decreased DBP (more than 10 mm Hg)

• Mild peripheral edema
• Low serum sodium
• Low hematocrit
  

Edema Clinical Signs and Symptoms: 

• Weight gain (primary symptom)
• Excess fluid
• Dependent edema (accumulation of fluid in lower parts of the body)
• Pitting edema
• Increased blood pressure
• Neck vein engorgement
• Effusions (pulmonary, pericardial, peritoneal)
• CHF

Associated Co-morbidities 

• CHF
• Liver disease
• Chronic Kidney Disease
• Polydipsia
• Cancer
• SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretion)
• Schizophrenia and other psychological disorders
• Endocrine disorders

Medications

Drug Name	Type of Drug	Used For	Side Effects
Chlorothiazide  & Hydrochlorothiazide	Diuretic	High BP and fluid retention Helps kidneys rid body of unneeded salts and water	Diarrhea Vomiting  Thirst Cramps Dizziness Hair loss Stomach Pain Loss of appetite Muscle weakness Rash Sore throat with fever Unusual bleeding
Conivaptan (Vaprisol)	V1A and V2 vasopressin receptor antagonist	Raise serum sodium in patients with euvolemic and hypervolemic hyponatremia Induces both sodium and water diuresis	Headaches Hypokalemia Infusion sight reaction (including phlebitis) Pyrexia Orthostatic hypotension
Tolvaptan	Vasopressin V2 receptor antagonist	Increase low levels of sodium in the blood Increases amount of water released in urine raising soium levels in blood	Thirst Dry mouth Fever Constipation Nausea Frequent and excessive urination Weakness Dizziness Vomiting Diarrhea

Diagnostic Tests/Lab Tests/Lab Values

Below are some of the most common laboratory tests that are used to assess a person’s hydration status:

• Serum Osmolality Tests are used as a measurement to determine the number of solutes present in the blood (serum). These tests are typically ordered to evaluate hyponatremia, which is generally a result of sodium lost in the excretion of urine or excess fluid in the bloodstream. Excess fluid in the bloodstream can be caused by water retention, drinking excessive amounts of water, decreased ability of the kidneys to produce urine, and the presence of osmotically active agents such as glucose. 

- Osmolality decreases with overhydration 

• Sodium Tests are also used to measure amounts of sodium in the blood (hypernatremia and hyponatremia). They are ordered when there is a suspected electrolyte imbalance, which could result in confusion, lethargy, weakness, decreased urinary output, and muscle twitching just to name a few. 

- Hyponatremia (low amounts of sodium in the blood) results from overhydration 
- Normal adult value: 135-145 mEq/L 

• Hematocrit Tests measure the percentage of blood that is comprised of red blood cells. Often times, this test is ordered as a part of a complete blood count. 

- Hematocrit decreases with overhydration 
- Normal adult male values: 40.7 - 50.3% 
- Normal adult female values: 36.1 - 44.3% 

• BUN (Blood Urea Nitrogen) Tests measure the amount of urea nitrogen in the blood and are typically ordered to evaluate kidney function. However, they can also be used in other medical conditions such as diabetes, CHF, MI, severe burns, and overhydration. 

- BUN decreases with overhydration 
- Normal adult value: 10-20 mg/dl

Etiology/Causes

Due to the etiologic complex, symptoms, and outcomes that are related to the two major forms of fluid excess being substantially different, they will be broken down individually. 

	Causes
Water Intoxication	Accumulation of solute-free fluid generally as a result of excess ADH from tumors or endocrine disorders Intake of only large amounts of tap water without balancing the ingestion of solutes Occurs most often in older adults recovering from the flu who drink additional water with associated diarrhea and vomiting, or in athletes who have lost compious amounts of body fluids and replaced them solely with water.
Edema	Can occur from many different situations, most commonly: Vein obstruction Decreased cardiac output Endocrine imbalances Loss of serum proteins (burns, liver disease, allergic reactions)

Systemic Involvement

• Digestive System - Liver disease is one of the primary causes of serum protein loss, which in turn causes edema in the extremities or abdomen (ascites). 
• Integumentary System - This system can be involved in a variety of ways. Much like liver disease, burns can be a common cause of serum protein loss, leading to edema in the body.  In addition, edema itself can cause signs and symptoms of redness, shiny skin, and tight or stiff skin. 
• Genitourinary System - The kidneys play a vital role in fluid and electrolyte balances. As age increases, the renal mass and glomerular filtration rate (GFR) decrease, which could in turn lead to the inability of the kidney to excrete free water when faced with fluid excess, causing hyponatremia.
  
• Cardiopulmonary System - An increase in intravascular fluid can result in CHF as well as increased pulse and respiration, whereas an increase in extravascular fluid may lead to edema, ascites, or pleural effusion.  Also, an excess of water will occur when there is an overabundance of water in the interstitial spaces or within the blood vessels (hypervolemia).  This can result in a fluid shift, where vascular fluid moves to interstitial or intracellular spaces, or vice versa. 
• Nervous System - Water intoxication will largely present with neurological symptoms due to the shifting of water into brain tissues causing a resultant dilution of sodium in the vascular space. 
• Endocrine System - Increased secretion of ADH which in turn causes excess solute free fluid. 

Medical Management

• Hypertonic Saline- a solution that contains sodium chloride and is given to patients to treat severe hyponatremia (serum sodium levels below 120 mEq/L).  These patients typically present with severe and potentially life-threatening symptoms such as: coma, seizures, and new focal neurological findings. 
• Continued lab and blood tests to monitor hydration status and electrolyte levels. 
• Managing edema 
• Controlling high BP (common in patients with edema) 

Physical Therapy Management

Physical therapy management is largely responsible for patient education and edema control in these individuals. Below are some common physical therapy treatment strategies:

Education on fluid consumption: 

• Educate patient on proper fluid consumption/restrictions to prevent extracellular fluid accumulation and water intoxication
• Educate patient on how to monitor daily fluid consumption by measuring out how much fluid you drink throughout the day

Managing edema:  

• Avoid constricting vessels to prevent venous pooling (don’t cross legs, wear tight clothing, etc.)
• Implement appropriate activity and position changes to prevent fluid accumulation in dependent areas
• Implement compression to the edematous extremity
• Elevating the edematous extremity to increase venous return and reduce edema
• The use of electrical stimulation and exercise to help reestablish the normal circulatory flow through muscle contractions
• Massage can reduce edema by increasing venous and lymphatic flow

Note: Some of the strategies to reduce edema may be contraindicated in CHF
Additional benefits may be achieved through the combination of multiple techniques

Differential Diagnosis

The following are some of the most common diagnoses that present with similar signs and symptoms of excess fluid/intoxication:

• Electrolyte imbalances
• Endocrine disorders
• Cancer
• CHF
• Liver disease
• Kidney dysfunction
• Vascular pathology

Case Reports/ Case Studies

Forensic aspects of water intoxication: Four case reports and review of relevant literature

Resources

Hyperhydration?

Hyponatremia Caused by Polydipsia

Fried or Soaked?

Strange but True: Drinking Too Much Water Can Kill