OVERVIEW

Hemolytic uremic syndrome (HUS) is a complex autoimmune reaction in which a gastrointestinal infection causes the destruction of red blood cells, and platelets, resulting in a fall in red blood cell level, platelet level and kidney injury.

The most common cause of this condition is the gastrointestinal infections. When the bacteria, E-coli, infect the gastrointestinal tract, toxins are released into the blood stream which destroys the blood cells circulating in the body causing premature death of the blood cells. This goes to affect the kidney by building up wastes of the destroyed blood cells. The kidney cells can also be destroyed by an attack from the immune reaction. If untreated on time, it can lead to kidney failure.

 

SIGNS AND SYMPTOMS

In haemolytic Uremic Syndrome (HUS), the signs and symptoms vary but indicate either symptoms of gastrointestinal tract infection and renal problems. Thus, the symptoms may include:

  • Bloody diarrhea.
  • Abdominal pain.
  • Pale skin.
  • Unexplained bruises or bleeding.
  • Decreased urination.
  • Abdominal swelling.
  • Blood in the urine.
  • Swollen face.
  • Swollen limbs.
  • Seizures which may be rare.

 

 CAUSES

HUS occurs where an immune reaction causes destruction to blood cells. This results in low red blood cell levels, low platelet levels, and kidney injury. It affects both sexes and cut across all age group but mostly affects children.

CHILDREN HUS

Escherichia Coli (E. coli) is the most common cause of HUS in children. E. coli bacteria are normally found in the intestines of healthy people. Thus the strain found in human does not cause harm. However, some specific strains of E. coli, passed on through contaminated food, are responsible for infections that can lead to HUS. Bodies of water that are contaminated with feces may also carry E. coli.

Other bacteria such as Shigella dysenteriae and Salmonella typhi can also cause HUS.

ADULT HUS

HUS in adults can also be triggered by infection with E. coli. There are also many non-bacterial causes of HUS in adults that are less common, including:

  • Pregnancy
  • HIV/AIDS infection
  • Quinine (used for muscle cramps)
  • Chemotherapy and immunosuppressant medication
  • Birth control pills
  • Anti-platelet medications
  • Cancer
  • Systemic lupus and glomerulonephritis

DIAGNOSIS

Laboratory tests are best ways to determine the cause of HUS and these may include:

Blood tests: these include complete blood count (CBC), blood urea nitrogen (BUN) and creatinine tests. These help to determine the amount of red blood cells platelets and the health of the kidney. An abnormal creatinine or BUN results indicates renal problems.

Urine Tests: these may include urinalysis and urine microscopy.

Stool Sample tests: collection and testing of patient stool can help detect any abnormality with the blood system.

TREATMENT

Common treatments for HUS may include:

  • Fluid Replacement: The key treatment for HUS is fluid replacement. This treatment replaces electrolytes that the body needs to function. Electrolytes are minerals such as calcium, potassium, and magnesium. Fluid replacement also increases blood flow through the kidneys. Your doctor will give you intravenous fluids, but may also encourage you to boost your fluid intake by drinking more water or electrolyte solutions.

 

  • Blood Transfusion: A red blood transfusion may be necessary if you have a low level of RBCs. Transfusions are performed in the hospital. Transfusions can relieve symptoms associated with low RBC counts, such as shortness of breath and extreme fatigue. These symptoms are consistent with anemia, a condition in which your body cannot produce enough red blood cells to supply the body organs with sufficient oxygen to carry on normal metabolism. This caused by the loss of RBC’s.

Dialysis: this is a temporary filtration of wastes from the kidney. This is done mostly to help restore the kidney to optimal function.

Other Treatments may include Platelet transfusion which may be necessary if platelet count is low. The plasma may be also be transfused in order to help the movement of the red blood cells transfused.

 

COMPLICATIONS

Complications may develop if there is no timely treatment and they can be grouped into long term and short term complications:

Long-Term Complications

The main complication of HUS is kidney failure. However, HUS can also cause:

  • high blood pressure
  • pancreatitis
  • altered mental state
  • seizures
  • cardiomyopathy
  • stroke
  • coma

Fortunately, most people are able to make a full recovery from HUS.

PROGNOSIS

HUS could be a life threatening condition although people tend to recover fully with early diagnosis and complete treatment.

PREVENTION

The most common cause of HUS is infections by E. coli. Although you cannot avoid these bacteria entirely, you can reduce your risk of infection by:

  • Washing your hands regularly.
  • Thoroughly washing utensils.
  • Keeping food preparation surfaces clean.
  • Keeping raw food separate from ready-to-eat food.
  • Defrosting meat in the refrigerator instead of on the counter.
  • Refrigerating meats in order to prevent bacterial growth on them.
  • Cooking meat to 160 degrees Fahrenheit to kill harmful bacteria.
  • Washing fruits and vegetables thoroughly.
  • Not swimming in contaminated water.
  • Avoiding ingestion of unpasteurized juice or milk.

 

SOURCES

  • Hemolytic uremic syndrome in children. (n.d.). National Kidney and Urologic Diseases Information Clearinghouse. June 21, 2012,http://kidney.niddk.nih.gov/kudiseases/pubs/childkidneydiseases/hemolytic_uremic_syndrome/
  • Hemolytic uremic syndrome: Post-diarrheal. (2015, June). http://www.cdc.gov/osels/ph_surveillance/nndss/casedef/hemolyticcurrent.htm
  • Mayo Clinic Staff. (2013, June 3). Hemolytic uremic syndrome (HUS). http://www.mayoclinic.com/health/hemolytic-uremic-syndrome/DS00876
  • Ferri FF. Hemolytic-uremic syndrome. In: Ferri’s Clinical Advisor 2016. Philadelphia, Pa.: Mosby Elsevier; 2016. https://www.clinicalkey.com. March 23, 2016.
  • Kliegman RM, et al. Hemolytic-uremic syndrome. In: Nelson Textbook of Pediatrics. 20th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. http://www.clinicalkey.com. March 23, 2016.
  • Tael MW, et al. Microvascular and macrovascular diseases of the kidney. In: Brenner & Rector’s The Kidney. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2011. http://www.clinicalkey.com. 2016.