Medical Physiology: Integration Using Clinical Cases
691
CASE 19–3
A Man with Abdominal Pain,
Fever, and Circulatory Failure
Case Presentation
A 21-year-old healthy college student was canoeing deep in
the Canadian wilderness when he felt the fi rst twinge of ab-
dominal pain. Thinking that he either ate some undercooked
fi sh or strained a muscle while paddling, he stopped to rest
for a day but the pain steadily intensifi ed. He began to shiver
and felt extremely cold even though it was a warm day. These
symptoms worsened during the 36 h it took to paddle to the
outpost camp and be airlifted to the nearest medical center.
Refl
ect and Review
#12
Based on your knowledge of the homeostatic
control of body temperature, why might this
young man feel cold despite the signs that his body
temperature is elevated (see Figures 16–18 and 16–19)?
What might be the cause of the abdominal pain
(see Figure 7–18)?
Physical Examination
On arrival at the hospital, the young man is confused and laps-
ing in and out of consciousness. He is rushed to the emergen-
cy room for examination. His temperature is 39.2°C (normal
range ~36.5°–37.5°C), heart rate is 140 beats/min (normal range
65–85), respiration rate is 34 breaths/min (normal ~12), and
blood pressure is 84/44 mmHg (normal ~120/80). He is tak-
ing deep breaths but his lungs are clear when listened to with a
stethoscope. His abdomen is rigid and extremely tender when
gently pressed on, especially in the lower-right quadrant.
Upon questioning, his friends state that he has not urinated
in over 24 hours. Therefore, a hollow tube called a
catheter
is
inserted through the urethra into the urinary bladder to col-
lect his urine. However, an abnormally small amount of urine
(10 ml) was collected (see Figures 14–20 through 14–24 for a
review of the control of urine output).
Refl
ect and Review #13
What mechanisms link low systemic blood pressure
in this patient to the low urine output (see Figure
14–20)?
What organs are located in the lower-right quadrant
of the abdominal cavity (see Figures 15–1 and 15–33)?
Laboratory Tests
Additional measurements were then performed, and the re-
sults are shown in
Table 19–3
.
Refl
ect and Review
#14
Explain the relationship between arterial
P
CO
2
and
pH values. Why is his arterial bicarbonate so low (see
Table 14–10)?
What functions do white blood cells serve? What
might be the cause of their abnormal values in this
patient (see Figure 12–71 and Table 18–1)?
What metabolic processes produce lactate
(lactic acid)? Under what circumstances would that
production be increased above normal (see
Figure 3–41 and Figure 13–38)?
Why did creatinine in the blood increase (see
Figure 14–12)?
Diagnosis
A catheter is placed into an arm vein so that an intravenous in-
fusion of isotonic saline (NaCl) can be started. Antibiotics are
added to the saline to fi ght the apparent infection. A
computed
tomography
(
CT
)
scan of the abdomen is performed, which
reveals an infl
amed appendix (
Figure 19–4
). The patient is
admitted to the intensive care unit (ICU) for continued intra-
venous fl uid replacement, physiological monitoring, and the
insertion of additional catheters that can be used for the mea-
surement of arterial and central venous blood pressures.
The patient is then taken to the operating room for ab-
dominal exploration. Surgeons remove an infl
amed appendix
that is found to have a small hole (
perforation
) and shows
signs of
necrosis
(dying or dead tissue).
Table 19–3
Initial Laboratory Results with the
Patient Breathing Room Air
Blood
Measurement*
Result
Normal Range
White blood
cells
25,000 per mm
3
4300–10,800 per mm
3
Arterial
P
O
2
90 mmHg
90–100 mmHg
Arterial
P
CO
2
28 mmHg
35–45 mmHg
A rterial pH
7.25
7.38 –7.45
Arterial
bicarbonate
13 mmol/L
23–27 mmol/L
Lactate
8 mmol/L
0.5–2.2 mmol/L
Glucose
5 mmol/L
4–6 mmol/L
Creatinine
2.2 mg/dL
0.8–1.4 mg/dL
*In actuality, these measurements are done in whole blood or blood serum.
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