09 May Hyponatremia common at August race
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At the Hotter ’N Hell Hundred Race, a 48-year-old male walks into the medical tent with his buddies who state the patient is not feeling will. He is “sick all over” and has a general feeling of malaise. Initial vitals are within normal limits and stable. Temperature is reasonably normal and the patient states he has had access to fluids and has been drinking copious amounts of liquid.
Patient denies any previous medical history, is taking no medications and has no known drug allergies.
Patient sits down in one of the patient beds in the medical tent where he appears to be resting comfortably, conversing with his friends.
C: Pt “not feeling well”
H: Pt has been participant in extensive bike race, having biked approximately 50 miles with outside temperature approaching 95˚F. Pt has been drinking copious amounts of water and has been eating normally.
A: Pt AOx3. Pt responding normally to all questions. Pt denies any LOC. Skin warm. Pt sweating normally for event. HEENT unremarkable. No abnormal fluids noted in EENT. No trauma noted in head, neck or back. Pt states he has no pain at rest, upon movement or upon palpation of head, neck or back. PERL. Chest unremarkable. Breath sounds clear bilat. No wheezes, rales or rhonchi noted in any lung fields. Abd non-tender, non-rigid in all four quadrants. Pt MAE without difficulty. Cap refill normal. Body temp. 99.4˚F.
R: Pt given 1L of normal saline at 100cc/hour
While in care of medical staff, patient progressively got worse, becoming extremely irritable. Friends noted changes in behavior and reported them to medical staff.
Initial sodium level reported as 125 via i-State portable electrolyte analyzer. Noted as severe electrolyte imbalance and low sodium. IV 3 percent saline established at 50cc/hour. After a very short while, pt reports, “I have to go to the bathroom.” Shortly thereafter, pt becomes incontinent and severely confused, moaning and not making intelligible sentences.
A: Pt responsive to verbal stimuli by looking in direction of voice, otherwise not responding appropriately. Skin warm. Other assessment remains unchanged. PO2 = 98 percent. EKG shows SR with no abnormalities.
Ambulance requested for transport to emergency department. After approximately two minutes, patient begins witnessed tonic-clonic-type seizure of less than one minute. Seizure activity does not repeat. IV fluid not flowing steadily during seizure activity. Pt transported to ED.
Pt was diagnosed with dehydration and hyponatremia in ED and given 1L of normal saline. He remained dazed and confused for approximately 24 hours after which time he regained normal mentation and put out 4.5 L of fluid.
Physicians, including Tim Noakes and his colleagues, first documented exercise-associated hyponatremia (EAH) in Durban, South Africa in 1981 and in 1985 in four athletes participating in endurance events longer than seven hours. By 2005, Keith Williamson applied what had been learned about hyponatremia in South Africa and other endurance events that take place in extremely hot weather to the Hotter ’N Hell Hundred race encouraging aggressive hypertonic saline treatment for patients who present with lower-than-expected blood saline values. Here are some of Williamson’s notes.
- Often, doctors are unwilling to aggressively treat hyponatremia despite clear evidence that acute-onset hyponatremia can clearly be treated with hypertonic saline. Patients, generally elderly, with chronic hyponatremia can be harmed by such treatment. While the reasons behind the causes of hyponatremia are unclear, it appears to have to do with the release of antidieuretic hormone (ADH) during exertion.
- A single liter of fluid will not hurt a patient while differential diagnosis is made between dehydration and hyponatremia.
- Blood saline levels: 135-145 — normal; 130-135 — mild hyponatremia; 125-130 — moderate hyponatremia; <125 — severe hyponatremia.
- Treatment of tonic-clonic seizure may include a benzodiazepine such as Lorazepam (Ativan), Midazolam (Versed) or Diazepam (Valium).