Setting: ED
CC: “I have diarrhea.”
VS: BP: 104/62 mm Hg; P: 94 beats/minute; T: 101.6°F; R: 18 breaths/minute
HPI: A 30-year-old resident in internal medicine comes to the ED at his own hospital with 1 day of watery brown diarrhea with blood in it and abdominal pain. He is generally a very healthy person and this is the first time this has happened to him. He does not recall an exposure to infected or contaminated food. None of his friends have diarrhea nor does anyone in his family with whom he has recently eaten.
PMHx/Medications: none
PE:
General: very weak and tired appearing
Abdomen: soft, but diffusely tender; no masses found
Chest: clear bilaterally
Initial Orders:
Orthostatic blood pressure measurement
CHEM-7
CBC
Blood cultures
Stool culture, ova/parasite examination
Stool WBCs
• Detect invasive diarrhea
• Sign of inflammation
• Not needed if blood visible in stool
Use methylene blue to detect WBCs in stool.
Orthostasis
• Detects >15% to 20% volume loss
• Pulse rate increase by 10 beats/minute
• Systolic BP decrease by 20 mm Hg
It is not always clear whether to use IV fluids in a person with diarrhea. Most infectious diarrhea is not severe enough to need IV fluids or antibiotics. Use orthostasis as an indicator of how severe diarrhea isas you move the clock forward.
Move clock forward 5 minutes to get results of orthostatic BP and pulse rate measurement:
Systolic BP drops to 86/52 mm Hg; pulse rate rises to 118 beats/minute
Orthostasis = Severe Diarrhea = IV Saline Needed
Volume Depletion Detection
1. Mechanoreceptors (“stretch” receptors) respond in the aorta and carotid sinuses.
2. Decreased stimulation results.
3. Cranial nerves IX and X transmit to the medulla.
4. Vasoconstriction and tachycardia result.
Orders:
Normal saline bolus, then continuously
Ciprofloxacin orally
Antibiotics for Diarrhea
Fever + Blood + Orthostasis
Pain + Tenderness
What is the most likely organism?
a. Campylobacter
b. Shigella
c. Yersinia
d. Viral
e. Staphylococcus
Answer a. Campylobacter
Viruses and staphylococci do not cause blood in the stool with diarrhea. The rest of the answer relies on statistical data. Campylobacter is more common than Salmonella, Shigella, Yersinia, or E. coli as a cause of infectious diarrhea, especially from food poisoning.
When bolusing with fluids, move the clock forward only 5 minutes to detect an improvement in BP and pulse rate. These effects will be nearly instantaneous on CCS.
• The carotid baroreceptor transmits to the brainstem by glossopharyngeal nerve.
• The aortic baroreceptor transmits to the brainstem by the vagus nerve.
Move the clock 5 minutes. Repeat vital signs
VS: P: 100 beats/minute; BP 106/70 mm Hg
Yersinia
• Gram-negative bacillus
• Siderophilic (likes iron to grow)
• Can grow in the cold
• Invades Peyer patches in ileum
• Simulates appendicitis
Reports:
CHEM-7:
Bicarbonate: 18 mEq/L (low)
Potassium: 3.0 mEq/L (low)
Chloride: 115 mEq/L (high)
Sodium: 140 mEq/L (normal)
CBC: WBCs 14,000/μL
Diarrhea = Normal Anion Gap Diarrhea = High Chloride Level + Low Bicarbonate Level
Metabolic Acidosis in Diarrhea
• There is a normal anion gap.
• The colon excretes bicarbonate.
• The colon excretes potassium.
Once you find potassium level abnormalities, you should replace potassium immediately and recheck the potassium level.
Orders:
Oral potassium
Continue IV saline and oral ciprofloxacin
Shigella
• It is resistant to stomach acid.
• A very small number of organisms can cause infection (10–100).
• It does not ferment lactose.
• Shigella toxin causes hemolytic uremic syndrome (HUS).
Move the clock forward 1 hour and repeat the potassium level and vital signs.
VS: BP 110/72 mm Hg; P: 92 beats/minute; T: 101°F
Report:
Potassium 4.0 mEq/L
Move the clock forward 12 hours. Most infectious diarrhea will show improvement in 12 to 24 hours and is self-limited. Give antibiotics for infectious diarrhea by mouth, because the gastrointestinal (GI) tract is where the infections is.
On the second hospital day, do an Interval History to see if the diarrhea is improving. Look at the fever curve to see if the temperature is coming down with the use of antibiotics.
Antibiotics need 12 to 24 hours to start working.
Interval History: “Frequency of diarrhea is decreasing. Temperature is 99.8°F.”
Orders:
CHEM-7
Campylobacter (Figure 10-7)
• Gram-negative bacillus
• Helical shape
• Grows at 42°C (higher than usual body temperature)
Figure 10-7. Gram stain of Campylobacter jejuni showing “comma”- or “gull wing”–shaped gram-negative bacilli (arrows). Campylobacters stain faintly and can be difficult to visualize. Original magnification ×1000. (Reproduced with permission from Brooks GF, et al. Jawetz, Melnick, & Adelberg’s Medical Microbiology, 25th ed. New York: McGraw-Hill; 2010.)
Move the clock to the third hospital day. Fever and diarrhea resolve.
Reports:
CHEM-7: normal
Stool Culture: Campylobacter
Blood Culture: no growth
You can discharge the patient and send him home. No further antibiotics are needed past 3 days for campylobacter.
This is a follow-up “as needed” type of case on the clock at the end.