What Causes Hypernatremia?

Patient Presentation
A 7-month-old male came to the emergency room with a 3 day history of watery diarrhea. The mother has tried some commercial electrolyte oral rehydration solution but the infant has refused the fluid for the last 1-2 days. She also tried his formula but he had refused that too. She said that she couldn’t tell when he last urinated because the diarrhea is so profuse. She denies any blood or mucous in his stool, and it currently is only brown water. He has been having increased sleepiness over the past 18 hours. She denies any fever but there was some emesis initially of the fluids she gave him. There is no one currently ill at home, but there is diarrhea in his daycare. There is no travel history nor exposures to pets other than the family dog. The past medical history shows a nasolacrimal duct obstruction as a neonate.

The pertinent physical exam showed that he was 8.640kg (75%) at his 6 month check and his current weight is 7.960 kg. Based on 75% for his age he should be ~9.00 kg. Therefore he is estimated to be 11.6% dehydrated. His blood pressure is 58/40, heart rate is 168 beats/minute, his respirations are 40/minute, and temperature is 37.8°C. He is lethargic but will awaken when stimulated and cry. His capillary refill is 4+ seconds on his trunk and longer in his extremities which are cold. He has poor skin turgor with mild tenting and his mucous membranes are dry. The rest of his HEENT, heart and lung exams are normal. His abdomen is relatively soft but he cries when examining him. His bowel sounds are hyperactive but there are no masses or organomegaly.

The diagnosis of severe dehydration with hemodynamic compromise due to enteritis was made and the patient was given 20 ml/kg of normal saline bolus. He continued to have low blood pressure and another bolus was given. The laboratory evaluation showed a serum sodium of 153 mEq/L, chloride of 116 mEq/L and potassium of 6.8 mEq/L.

The patient’s clinical course was that he was taken to the pediatric intensive care unit for fluid management. He was given additional fluid and then started on 0.2 normal saline to correct his hypernatremia over 48 hours. Ongoing diarrhea losses were also replaced by intravenous fluids. KCl was given after urination was established. He became more alert over this time and on day 3 began to take sips of fluid. The diarrhea also improved and he was sent to the floor on Day 4 of hospitalization. The cause of the diarrhea was Rotavirus.

Discussion
Hypernatremia is a serum sodium of > 150 mEq/L. Basic causes are too much sodium or too little free water.

If body weight is normal or increased, there is an increase in total body sodium without an appropriate increase in total body water. Normally when the serum sodium is increased there is transient hypertonicity of the plasma which causes the thirst center to be stimulated and antidiuretic hormone (ADH) to be released. The thirst center tells the person to drink more water and ADH causes the kidney to retain free water. This normally will allow the plasma tonicity to go back to normal. Treatment is by treating the underlying cause and appropriate free water administration.

If the body weight is decreased, there is a lower amount of free water with a relative increase in total body salt. This occurs usually when there is hypovolemic dehydration such as diarrhea and inadequate free water intake. Normally ADH is produced to increase the free water but without adequate access to free water, the hypernatremia continues to be maintained. Treatment is by treating the underlying causes and appropriate free water administration.

Severe diarrhea is one of the most common reasons for hypernatremia. Patients with hypernatremic dehydration have both lower total body sodium and free water, but there is relatively more free water loss than sodium loss. Patients then develop hypernatremia. Because the hypernatremic plasma is hypertonic, intracellular free water passes into the extracellular environment which helps to maintain body’s hemodynamics. Therefore patients with hypernatremic dehydration usually are 3-5% more dehydrated than estimates based on clinical signs.

Patients who have had a prolonged period of hypernatremia should have their hypernatremia progressively decreased over a prolonged period of time to minimize the risk of cerebral edema. During hypernatremia, other osmolytes are produced intracellularly to help to balance the electrolytes extracellularly. These additional intracellular osmolytes are not created nor dissipated quickly. Therefore if additional free water is added too quickly to the extracellular environment to correct the hypernatremia, then as the serum sodium decreases, the extra free water can enter cells where the additional osmolytes are and this can lead to cellular edema.

While patients are given normal saline (sodium and fluid to expand the intravascular circulation immediately) if they are hemodynamically compromised, patients are often given Dextrose 5% (or 10%) + 0.2% normal saline (smaller amount of sodium and more free water) to correct the hypernatremia over 48 or more hours. Potassium and chloride are also replaced appropriately after the patient is voiding and it is obvious there is not a component of intrinsic renal disease. Patients should be monitored frequently (every 4-6 hours) and changes to the intravenous fluids made promptly. If the serum sodium decreases too quickly and cerebral edema and seizures occur, patients are usually given 3% saline to increase the serum sodium and the seizures usually stop after 4 ml/kg of 3% saline. Slower correction of the hypernatremia can then begin again.

Learning Point
Causes of hypernatremia include:

If body weight is normal or increased, there is an increase in total body sodium without an appropriate increase in total body water.

  • Urine sodium is high and urine osmolality is high
    • Salt poisoning
    • Excessive salt administration, such as salt tablets or medications such as sodium bicarbonate, hypertonic intravenous fluids, salt-water ingestion, excessive use of soy sauce, inappropriate mixing of infant formula, inappropriate use of salt instead of sugar
    • Cellular lysis such as tumors, rhabdomyolysis, crush injury
  • Urine sodium is variable and urine osmolality is low
    • Central hypodipsia
    • Reset osmostate – usually because of brain trauma
    • Hyperaldosteronism – infrequent
    • Cushing syndrome – infrequent
  • If the body weight is decreased, there is a lower amount of free water with a relative increase in total body salt
    • Urine sodium is low and urine osmolality is high
      • Diarrhea
      • Insensible water loss – fever, tachypnea, radiant warming of premature infants, burns
      • Excessive sweating
      • Lack of access to free water
    • Urine sodium is high and urine osmolality is isotonic to high
      • Diuretic
      • Glycosuria
      • Post urinary tract obstruction diuresis
      • Acute tubular necrosis, diuretic phase
      • Acute tubular necrosis, non-oliguric
    • Urine sodium is high and urine osmolality is isotonic to high
      • Diabetes insipidus
        • Central (non production of ADH)
        • Nephrogenic (non response to ADH)

    Questions for Further Discussion
    1. What causes hyponatremia?
    2. What causes hypokalemia? THE differential diagnosis is available here

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for these topics: Sodium and Dehydration.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1651-2.

    Moritz ML, Ayus JC. Intravenous fluid management for the acutely ill child. Curr Opin Pediatr. 2011 Apr;23(2):186-93.

    Powers KS. Dehydration: Isonatremic, Hyponatremic, and Hypernatremic Recognition and Management. Pediatr Rev. 2015 Jul;36(7):274-83.

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa

  • What is Usher Syndrome?

    Patient Presentation
    A 2-year-old female came to clinic with a 2 day history of upper respiratory infection symptoms, pulling on her ears, and being cranky. She had a temperature of 38.8°C maximum that improved with acetaminophen. The past medical history revealed 4 previous otitis media infections with the last one being 6 months ago. The pertinent physical exam showed a cranky appearing female with a temperature of 38.2°C, respiratory rate of 24 and growth parameters that were 50%. HEENT showed copious clear rhinorrhea and bilateral tympanic membranes that were red and bulging with yellow purulent material behind the tympanic membrane. There was no membrane movement in either ears.

    The diagnosis of bilateral acute suppurative otitis media was made. The mother said that she was glad to know what the problem was but was very anxious because this was her 5th ear infection and she wanted a referral to an otolaryngologist. “I don’t really want her to have surgery for her ears, but my cousin’s baby was born deaf and he’s just been diagnosed with something called Usher. I looked it up on the Internet and it’s really bad. They can have eye problems too. I’m really worried about her hearing and think I would feel better if I knew she wasn’t going to have hearing problems,” she explained. “I’m very sorry to hear about your cousin’s child. I don’t remember exactly what Usher is, but will try to find out. Your daughter’s newborn hearing test should have been normal otherwise we would have sent her to the ear doctor already but I’ll check to make sure. Have you ever thought that she was having problems hearing, either now or before?” the pediatrician inquired. “I think her test when she was born was normal and I’ve never been worried, but she’s had these infections and now this baby who is deaf. I’m just very worried,” she replied. “We’ll I can understand that. It is not unreasonable to have her hearing tested after having 5 ear infections, but her last one was a while ago and for most children the ear infections stop as they get older and there are usually no problems with long-term hearing loss. I’ll order a hearing test for her after this ear infection is over. In the meantime, I’ll try to find out more about Usher, ” she offered. “I think I will feel a lot better after I know that her hearing is normal,” the mother said.

    Discussion
    Over 7000 diseases are considered rare disorders according to the National Organization for Rare Disorders® (NORD, rarediseases.org). NORD is a patient advocacy organization dedicated to individuals with rare diseases and the organizations that serve them. They have information on about 1200 rare diseases on their website (https://rarediseases.org/for-patients-and-families/information-resources/rare-disease-information/).

    Hearing loss (HL) is not rare and is a common problem across the ages. It affects 360 million people worldwide which is about 5% of the population. There are many causes of hearing loss and a differential diagnosis can be reviewed here. HL can be classified as congenital vs acquired, with congenital being further classified according to the genetic inheritance (e.g. recessive, dominant, sex-chromosome), onset, severity and whether it is associated with syndromes or not.

    Retinitis pigmentosa (RP) is a group of retinal degenerative diseases that have loss of photoreceptors and retinal pigment deposits. Non-syndromic RP causes visual deficits over several decades. Initial symptoms are night blindness and later patchy peripheral vision losses that evolves into scotoma, tunnel vision and blindness. There are many syndromes which have RP as part of their symptoms with Usher syndrome (14% of all RP cases) and Bardet Biedel syndrome as two of the most common ones.

    Learning Point
    Usher syndrome (US) was described as early as 1858, but it is named for British ophthalmologist Charles Usher who noted the genetic inheritance.
    US has later onset RP and congenital, bilateral, neurosensory hearing loss.
    Of the syndromes known to affect both hearing and vision, “…about half of the affected cases are caused by mutations attributed to Usher syndrome.”
    US is autosomal recessive with an estimated prevalence of 3-10/100,000 people. There are multiple genes involved (chromosomes 1, 3, 10, 11, 14, 21).
    There are 3 major types and a possible 4th.

    • Type I – 70-75% of patients – has congenital severe to profound hearing loss, congenital vestibular dysfunction, RP begins in usually < 10 years
    • Type II – 26% of patients – has congenital moderate to severe hearing loss (quite “hard of hearing”), no vestibular dysfunction, RP is diagnosed ages 10-40 years
    • Type III – 4% of patients – has variable progression hearing loss that starts in years 20-30, variable vestibular dysfunction, RP starts in 20s.
      It is least common, but more common in some populations including Ashkenazi Jewish and Finnish populations.

    • Type IV – its existence is being debated by researchers and may be X-linked recessive

    Treatment is directed by ophthalmologists and otolaryngologists who along with audiologists, speech and language pathologists and other professionals may help patients with different therapies. Some patients take Vitamin A as part of their treatment.

    Questions for Further Discussion
    1. How good are vision and hearing screening tests? A review can be found here https://pediatriceducation.org/2011/11/14/how-good-are-hearing-and-vision-screening-tests-in-children-2/
    2. What are indications for referral to a geneticist?
    3. What are indications for cochlear implants?

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for this topic: Usher Syndrome

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Usher Syndrome. National Organization for Rare Diseases. Available from the Internet at https://rarediseases.org/rare-diseases/usher-syndrome/ (cited 9/7/17).

    Hamel C. Retinitis pigmentosa. Orphanet J Rare Dis. 2006 Oct 11;1:40.

    Koffler T, Ushakov K, Avraham KB. Genetics of Hearing Loss: Syndromic. Otolaryngol Clin North Am. 2015 Dec;48(6):1041-61.

    Usher Syndrome, Type i; USH1 #276900. Online Mendelian Inheritance in Man.
    Available from the Internet at Koffler T, Ushakov K, Avraham KB. (rev. 3/8/16, cited 9/6/17).

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa

    What Are the Health Needs of Incarcerated Youth?

    Patient Presentation
    A 15-year-old male came to clinic for his health supervision visit. He was doing well and there were no concerns. His mother had a red mark on her cheek that the pediatrician noticed and asked about. The mother and son both started to grin somewhat. “We’ll I was the innocent bystander in a fight between two teenagers at the juvenile detention center I teach at. They started to go at it and when the probation officers came in to break it up, I got caught off balance trying to move away and tripped over a desk and hit the edge. I didn’t actually get hit but it looks like I was. Actually it could have happened in any high school, its just seems worse because I work at the ‘juvie jail,'” she explained. She went on, “I really like working there because the kids have so many needs. Their stories can be really, really sad and we see lots of mental health, physical and social issues. The classroom at least is a consistent place for all of them.” Later, the pediatrician looked up what are some of the health care needs of incarcerated youth.

    Discussion
    In the US during 2011, ~60,000 youth were incarcerated at some time in a correctional facility. Boys are detained more than girls (86% vs 14% respectively in the US, 95% male in the United Kingdom in 2014) but girls have more health issues. There are racial and ethnic differences with 38-40% of detainees being black, 23% being Hispanic/Latino and 32% being white, and 5% other. For detained youth, 5% are for violent crimes, 22% for non-violent property crimes and the majority of the rest are for non-violent offices such as substance use. The average length of detainment is 3-4 months and unfortunately the rates of recidivism are higher for youth than for adults; for youth, 75% are rearrested within 3 years. Detained youth have a higher risk of mortality at 4x the general population; girls have an 8x higher rate.

    A comprehensive view of their health care needs to be provided to the youth, upon their arrival, during detention, transitioning out of and after detention. For formerly detained youth, primary care physicians can help with continuing primary care including immunizations and screenings for sexual and mental health issues, determining if consultative care is needed and referring as necessary for pediatric specialty care, mental health or substance abuse treatment, working with local school districts to assist with educational/academic needs, working with social services to help with overall family needs, and providing information to the probation officers and other legal system representativse as appropriate.

    Within the detention system, girls are less common and therefore represent a special population. LGBTQ (Lesbian, Gay, Bisexual, transgender or questioning) youth were 15% of the detained population (11% for boys, and 27% for girls). Youth involved in sex-trafficking are also viewed as a special population.

    Learning Point
    Many health problems are seen at higher rates in detained youth. The priority primary health needs include dental, infectious illness, reproductive health needs and trauma-related injuries. In the United Kingdom the most common physical health needs were: vision (13%), oral health (12%), skin problems (12%), asthma (11%), weight problems (11%) and genito-urinary problems (10%). In the United Kingdom mental health prevalence rates showed personality disorder (~84%), drug dependency (~57%), depression (~50%), neuroses (52%) and psychosis (8%).

    Health problems of detained youth include:

    • Mental – 66% of boys and 75% of girls have at least 1 mental health need, many are undiagnosed
      • Behavior
      • Conduct disorder
      • Post traumatic stress disorder
      • Mood disorders including anxiety and depression and suicidality
        • Suicidality is very common with 52% of youth reporting recent suicidality and 1/3 with an attempt.
      • Neurodevelopment
        • Attention/ADHD
        • Learning disabilities including specific learning disabilities such as dyslexia
      • Substance use and abuse – alcohol and marijuana use are especially high among detained youth (74 and 84% respectively). Girls are more likely to use other substances.
        • Alcohol
        • Cocaine or crack
        • Crystal methamphetamine
        • Ecstasy
        • Marijuana or hashish
    • Physical
      • Acute self-limited illness, e.g. upper respiratory infections, dermatological problems
      • Chronic problems
        • Asthma
        • Diabetes
        • Seizures
        • Sickle cell disease
      • Dental
        • Dental decay
        • Abscess of the jaw
        • Gum disease
      • Pain – females tend to report more musculoskeletal pain
        • Abdominal pain
        • Backache
        • Headache
      • Sexual – detained youth have higher rates of sexual activity and lower rates of contraception
        • Sexually transmitted infections
          • Chlamydia, gonorrhea, HIV and Hepatitis C, syphilis
        • Pregnancy
          • “…1 in 5 detained youth either [are] having a child or expecting a child.” Fourteen percent of boys and 9% of girls already have a child.
      • Trauma-related injury
      • Vision
  • Other
    • Under education
    • Under immunization

    Questions for Further Discussion
    1. What training have you had about detained youth?
    2. How are the health needs of detained youth addressed in your clinical location?

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for this topic: Child Behavior Disorder

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Perry RC, Morris RE. Health care for youth involved with the correctional system. Prim Care. 2014 Sep;41(3):691-705.

    Lennox C. The health needs of young people in prison. Br Med Bull. 2014 Dec;112(1):17-25.

    Barnert ES, Perry R, Morris RE. Juvenile Incarceration and Health. Acad Pediatr. 2016 Mar;16(2):99-109.

    Author
    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa