Vascular
CASE 45: abDominal pain anD metaboliC aCiDoSiS
history
A 65-year-old man presents to the emergency department with an 8-h history of severe generalized abdominal pain. Earlier in the day he passed fresh blood mixed in with his stool. His past medical history includes diabetes, hypertension and atrial fibrillation. He is not currently taking any anticoagulation therapy for his atrial fibrillation. He smokes 20 cigarettes per day.
examination
He has difficulty lying still on the bed. He has a temperature of 37.5°C with an irregularly irregular pulse of 110/min. His blood pressure is 90/50 mmHg. Abdominal examination shows generalized tenderness with absent bowel sounds. Rectal examination confirms loose stool mixed with some fresh blood.
INVESTIGATIONS
|
|
|
Normal |
haemoglobin |
|
12.2 g/dl |
11.5–16.0 g/dl |
mean cell volume |
|
86 fl |
76–96 fl |
White cell count |
|
13.2 × 109/l |
4.0–11.0 × 109/l |
platelets |
|
252 × 109/l |
150–400 × 109/l |
Sodium |
|
138 mmol/l |
135–145 mmol/l |
potassium |
|
4.4 mmol/l |
3.5–5.0 mmol/l |
urea |
|
3.2 mmol/l |
2.5–6.7 mmol/l |
Creatinine |
|
72 μmol/l |
44–80 μmol/l |
C-reactive protein (Crp) |
36 mg/l |
<5 mg/l |
|
amylase |
|
126 iu/dl |
0–100 iu/dl |
ph |
|
7.29 |
7.36–7.44 |
partial pressure of Co2 |
(pco2) |
3.5 kpa |
4.7–5.9 kpa |
partial pressure of o2 (po2) |
8.9 kpa |
11–13 kpa |
|
base excess |
|
–6.5 |
+/–2 |
lactate |
|
9.4 |
<2 mmol/l |
Questions
•What does the arterial blood gas show?
•What is the most likely diagnosis?
•What are the differential diagnoses?
•What other investigations can you suggest?
•What is the treatment and prognosis for this condition?
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100 Cases in Surgery
ANSWER 45
The arterial blood gas shows a metabolic acidosis (low pH, negative base excess and high lactate) with partial respiratory compensation (low pcO2). The most likely diagnosis is mesenteric ischaemia secondary to superior mesenteric artery thrombosis or embolism. Atrial fibrillation is a risk factor for embolism.
!Differential diagnoses
•pancreatitis
•ruptured abdominal aortic aneurysm
•perforated viscus
The investigation should include:
•Routine bloods and serum amylase to exclude pancreatitis
•Electrocardiogram
•Chest x-ray: may show free air under the diaphragm
•Abdominal x-ray: typically ‘gasless’
•Computerized tomography of the abdomen: not always diagnostic with ischaemic bowel but would help to exclude other pathologies (e.g. an abdominal aortic aneurysm)
The prognosis associated with this condition is poor, with less than 20 per cent survival. The patient should be resuscitated with intravenous fluids and broad-spectrum antibiotics given. The patient should then be taken for urgent laparotomy where any dead bowel is resected. Revascularization by embolectomy or bypass may salvage any bowel that has a ‘dusky’ appearance and is of dubious viability. If there is any doubt about viability, then both ends of the bowel should be left in situ or exteriorized and primary anastomoses avoided. The patient may require a subsequent laparotomy at 24–48h to confirm viability, and an anastomosis can be performed at that time.
KEY POINTS
•atrial fibrillation increases the risk of arterial embolization.
•a re-look laparotomy at 24 h may be required to check for further intestinal ischaemia.
106
Vascular
CASE 46: painFul FingerS
history
A 30-year-old woman attends the surgical outpatient clinic complaining of painful fingers. She notices the pain particularly during the winter months when it is colder. When she is outside, the fingers firstly become white, then blue and then become red and start to tingle. She smokes ten cigarettes per day and is currently taking atenolol for hypertension.
examination
On examination, the fingers have a reddish tinge and the skin feels dry. Examination of the neck is normal and all pulses in the upper limbs are present.
Questions
•What is the most likely diagnosis?
•Can you explain the sequence of colour changes?
•What are the environmental factors that can exacerbate this condition?
•What investigations would you carry out?
•What treatments would you suggest?
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100 Cases in Surgery
ANSWER 46
This is Raynaud’s phenomenon. When this disorder occurs without any known cause, it is called Raynaud’s disease, or primary Raynaud’s. When the condition has a likely cause, it is known as Raynaud’s phenomenon. A thorough investigation must exclude all known causes before a patient is considered to have primary Raynaud’s.
The majority of patients are female (up to 90 per cent) and the prevalence of this condition can be as high as 20 per cent in the general population. Raynaud’s can affect the hands, feet and even the tip of the nose. Digital artery spasm results in blanching of the fingers; the accumulation of deoxygenated blood then gives the fingers a bluish tinge and finally the fingers become red due to reactive hyperaemia. Accumulation of metabolites causes paraesthesia.
!Causes of Raynaud’s phenomenon
•Systemic lupus erythematosus
•Systemic sclerosis (scleroderma)
•rheumatoid arthritis
•Cold agglutinins
•polycythaemia
•oral contraceptives
•beta-blockers such as atenolol (as in this case)
•occupational (vibrating tools)
•Cervical rib
Tests to rule out a possible cause include a full blood count, urea and electrolytes, cryoglobulins, erythrocyte sedimentation rate, rheumatoid antibodies, antinuclear factor and antimitochondrial antibodies. Duplex scanning can be used to assess the arterial supply of the limb.
It is important to keep the extremities warm and avoid the cold by use of gloves/warm socks or even moving to a warmer climate if possible. Drugs (e.g. beta-blockers, contraceptives) that exacerbate the condition should be stopped. Similarly, smokers should be encouraged to stop. Calcium-blocking drugs (e.g. nifedipine) and 5-hydroxytryptamine antagonists have all been used with some success but can cause severe headache as a side-effect.
KEY POINTS
• medications should be excluded as a cause of raynaud’s phenomenon.
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