Dehydration and tachycardia

Bob was 18, a high school senior, a good student, played soccer and ran track, excelling at the 400. He was in the office with his mother to follow up after an ED visit and brief hospital stay earlier in the week. The discharge sheet they brought in noted that he had responded promptly to treatment for a viral illness with vomiting, diarrhea and dehydration (VDD), but because of an unexplained tachycardia he was advised to be seen ASAP to obtain a referral for cardiac evaluation. They were quite anxious and more than a little upset that we hadn’t responded to their phone request for cardiac referral, suggesting instead that we start with an OV to find out more about what was going on.

He had had the sudden onset of mid epigastric pain with multiple episodes of emesis over 4-5 hours. The vomiting tapered spontaneously at that point but significant nausea and the abdominal pain remained and he developed diarrhea. The nausea (and a nervous mother) prevented him from drinking liquids and they became concerned about dehydration and therefore had proceeded to the ED.

In the ED he was noted to have a BP of 96/62, pulse of 142 (strong and regular), warm and dry skin with no comment about skin turgor, hyperactive bowel sounds, and dry oral mucosa. His WBC was 12,200 with an unremarkable differential.  His sodium was 142, K 3.9, BUN 12, Creatinine 0.8 and a urine was pale yellow with no cells or sediment and no recorded specific gravity. His amylase was 46 and there were no abnormal tests otherwise on a metabolic panel. His CXR and EKG were normal. This history, exam and lab were all consistent with a viral gastroenteritis with mild dehydration. Based on his low BP and high pulse he was felt to warrant Zofran to prevent further vomiting and ‘fluid resuscitation’ with 3 Liters of normal saline. His BP was noted to increase slightly to 100/66 (his baseline in our office on previous visits) and his pulse dropped to the low 120s. Because of the persistent elevation of his pulse he was kept overnight, received several additional liters of fluids. By the next afternoon he was reporting no more nausea and only minimal abdominal pain. His pulse was down to 112 with a BP of 102/64. No orthostatic BPs were recorded in the ED or during his hospital stay. (This is an inexpensive way to assess volume status, part of the standard approach to dehydration.) He tolerated a test meal of jello and broth and crackers and was discharged. He was told there was probably a cardiac issue causing his tachycardia and that he should contact his PCP for referral for a cardiac  evaluation. A Holter monitor (measuring rhythm over 1-3 days) and echocardiogram (to look at valve and muscle function) were mentioned. His TSH was noted to be 1.4 (normal) in the discharge summary. He was told to restart his regular medications.

It was now three days later and he had restarted his usual medications. He said he had felt fine the day after he went home, but now thought that his heart was speeding up again. He was upset to the point of tears that track practice was starting that week and he had been told he could not practice until he was cleared by a cardiologist. (Now I understood their distress at the delay caused by seeing me.) His BP was 104/70 and his resting pulse was 106. After brief but mild exercise (10 pushups) in the exam room, his pulse reached 148.

I pursued some questions about his cardiorespiratory status.  Yes, he had played soccer last fall. No, he had not had any problems during soccer season, but he hadn’t played as much as he had the previous years. No, he hadn’t had an injury. No, there was not a crop of hot shot underclassmen. He had just gotten tired more easily than the year before. The coach would take him out when he seemed to be slowing down. Oh really? Any chest pain or pressure or tightness? No, but his heart would pound more than it used to. He avoided maximum effort in practice and on the field, and the coach had him playing lots of ‘left bench and defensive water bottles.’ No, he hadn’t told anyone about this. He thought he was just out of shape and they would think he was being a wuss. No, he hadn’t done much exercise during the winter but was really looking forward to his senior year track season and desperate to find out what was so wrong with his heart. And more than a little frightened. He had been online and had read about cardiomyopathy and myocarditis and muscular dystrophy heart disease.

I asked if he had had problems the previous year during Spring track? Nope. In fact, he had tied a school record in the 400 and had competed in both the 400 and 800 and some relays at the State meet, with no symptoms at all.  Could he tell me when he very first thought there was something wrong? Probably in July after he came back from a camping trip. Or maybe in August. Sometime in the summer, after school was done.

He had no family history of heart disease. He did not smoke or use drugs (‘Are you kidding? I’m a runner, not a football player.’) He was not using any supplements, just the medication he took for his irritable bowel.

His exam was entirely benign other than the mild tachycardia. I had him walk around the office twice briskly and his pulse was 146 and strong and regular.

We looked together at his electronic health record. First we checked his problem list: HM, chronic insomnia, and IBS (irritable bowel syndrome). No clues there. The we verified that he had no med allergies. Then his med list. Hmmm. His med list contained a topical steroid for intermittent eczema, and nortriptyline for his IBS and insomnia, which I pointed out to him, we had started last summer. Then we looked at the flow sheet. His BP has been in the 94/54 - 108/66 range for the last 5 years and his pulse had been in the 60s until a visit for a fever and cough diagnosed as a viral illness last November, when it was 112, and today.

I suggested that it was likely that his tachycardia was my fault, and that it appeared that I had missed it last Fall (for which I apologized). I said the nortriptyline that was controlling his frequent diarrhea and had totally fixed his chronic insomnia, seemed to have created a new problem: tachycardia. He said that he had asked if it could be the medication both in the ED and the next morning on the medical floor (he had looked it up on the internet with his smart phone) but had been told twice (once by a physician and once by a nurse) that it was from the dehydration. 

I proposed that we stop the nortriptyline and have him monitor his pulse at rest and after activity, and come back in a week for follow-up. He and his mother were reluctant, and still wanted a referral to a cardiologist. I suggested a compromise: we would start the referral process, but in the interim he would stop the nortriptyline, monitor his pulse, and see me in a week. When they learned that the appointment with the cardiologist would be in 7 weeks, they agreed to try my plan - but were clearly not pleased.

One week later they were back. By 72 hours, his heart rate was in the low 60s at rest, and on the day before the visit he had done a moderately intensity interval workout with heart rates up to 170 and was surprised that he didn’t feel like his heart was pounding.  And with a great big smile he said: “And I’m friggin fast again, doc. And I don’t get tired when I run, not like last Fall.”

We spent the next 5 minutes reviewing a list of alternative therapies for his IBS and insomnia and planning a series of trials, as well as talking about a GI referral if we were unsuccessful. And then he said: “Can you cancel the heart appointment for me? I don’t want to hurt the doctor’s feelings, but it doesn’t seem like it’s worth it any more.” His mother agreed. (So did the cardiologist when I shared this incident later in the week.)


I wonder:

  • The ED had access to his office chart and the medication list. Did they not look? Or did they not see?
  • Why did they insist on a diagnosis of tachycardia from dehydration without orthostatics, with a probably normal urine and with normal electrolytes and BUN/creatinine and no specific gravity?
  • Why did his question about the nortriptyline get dismissed?
  • When I prescribed nortriptyline, did I tell him to watch for tachycardia and he forgot, or did I not tell him?



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