Masquerading Abdominal Pain
Anne Messman, M.D.
Case: A 64-year old white female presents to the Emergency Department with a
chief complaint of diffuse abdominal pain for the past 6 hours. She also
complains of some nausea, vomiting, and a headache that began just before the
abdominal pain started. Her past medical history is significant for hypermetropy
(long-sightedness) that is corrected with glasses. She has no history of
migraines and does not get headaches often. This is not “the worst headache
ever” but she is in some distress due to the pain. Her abdominal pain is poorly
localized, and on physical exam she has some mild diffuse tenderness to
palpation. The remainder of your focused physical exam is unremarkable.
Concerned about her abdominal pain, you order a CBC, electrolytes, BUN,
creatinine, liver function tests, amylase, lipase, total/direct/indirect
bilirubin, and urinalysis, all of which return within normal limits. At this
point you are considering an abdominal CT. You go into the patient’s room to
tell her you will be ordering the CT, and she remarks that her headache is
worsening and her vision is somewhat blurry. You did not notice this before, but
it seems that the conjunctiva of her left eye is somewhat injected and her left
pupil seems slightly dilated. You begin to suspect that something else is going
on with this patient completely unrelated to her abdominal pain. What is on your
differential diagnosis? What should you order next?
Article: When a patient presents with abdominal pain, it is easy to get
caught-up looking for an abdominal cause for their pain, even if they are also
complaining of non-abdominal symptoms. Although acute angle closure glaucoma (AACG)
is a relatively rare entity, it is a diagnosis that must not be missed in the ED
and should always be somewhere on the differential of a patient complaining of
abdominal pain, nausea and vomiting, or headache. If missed, this disease can
lead to optic nerve atrophy and permanent loss of vision within hours. In an
ideal world, all patients would read the textbook and present with an acutely
red and painful eye, blurred vision with halos around light, with onset of
symptoms after emerging from a dark environment like a movie theater.
Unfortunately, this is often not the case and the patient’s main complaints may
lead the emergency physician down the path of an abdominal work-up or migraine
treatment.
In about 90% of cases, AACG results from pupillary block in which pupillary
dilation causes apposition of the lens and the iris, resulting in obstruction of
aqueous outflow from the eye. Normal intraocular pressure is 10 to 21 mmHg,
however when aqueous outflow is obstructed, pressure will increase beyond this
normal range, often (but not always) causing pain and loss or change in vision.
AACG is more common in far-sighted patients, who already have a shallow anterior
chamber angle. It is also more common in patients over the age of forty, and
occurs more in women. Other associated symptoms include frontal headache,
nausea, vomiting, and abdominal pain. Rarely, AACG may present as painless loss
of vision, confounding diagnosis yet again. In approximately 50% of cases, the
patient will report similar episodes in the past, frequently with onset of
symptoms at night due to pupillary constriction, and resolution of symptoms with
sleep.
If you suspect or want to evaluate for AACG remember, as is often the case, that
your history and physical exam are extremely important. Patients may not offer
that their vision has changed in conjunction with their headache or abdominal
pain, so always ask. Make sure that you have an accurate medication list, as
there have been case reports of AACG due to tricyclic antidepressants,
anticholinergics, selective serotonin reuptake inhibitors, intranasal
phenylephrine, topiramate, and nebulized albuterol. During your physical exam,
look at the eye carefully. There may be circumcorneal conjunctival injection, a
steamy cornea, or a mid-dilated (4-6 mm) and fixed pupil; but you won’t know if
you don’t look. You can also have the patient’s visual acuity tested; patients
with AACG often have impaired visual acuity. The affected globe may also feel
tender and firm compared with the non-affected globe owing to the increase in
intraocular pressure. Tonometry should obviously be performed; pressures greater
than 70 mmHg can be seen in AACG, and pressure greater than 40-50 mmHg can cause
rapid visual loss; any pressure outside of the normal range (i.e. greater than
21 mmHg) should raise suspicion.
Once the diagnosis of AACG is made, treatment should be initiated immediately in
order to have the best chance of preserving vision. Ophthalmology should be
consulted emergently. Treatment in the emergency department is aimed at
decreasing intraocular pressure. This can be accomplished via suppression of
aqueous humor production; typical agents used include topical beta-blockers,
alpha-adrenergic agonists (ex. apraclonidine) and oral or intravenous carbonic
anhydrase inhibitors. The decision to use intravenous versus oral carbonic
anhydrase inhibitors will depend on the patient’s degree of nausea and/or
vomiting. Intravenous mannitol should be used as an adjunct to decrease the
intraocular pressure unless contraindications exist; contraindications include
severe dehydration, active intracranial bleeding, pulmonary edema, and
well-established anuria due to severe renal disease. Once the intraocular
pressure is reduced below 40 mmHg, it is important to prevent recurrence of the
angle closure. Pilocarpine 1% or 2% should be used topically after pressure
reduction in order to make the pupil miotic, thereby reducing the chance of
recurrence.
A summary of the treatment of acute angle closure glaucoma follows:
1. Identify mid-dilated, nonreactive pupil with increased intraocular pressure.
2. Topical beta-blocker (Timoptic 0.5%), one drop.
3. Topical alpha-agonist (Iopidine 0.1%), one drop.
4. Topical steroid (Pred Forte 1%), one drop every 15 minutes for four doses,
then hourly.
5. Carbonic anhydrase inhibitor (acetazolamide) 500 mg IV or PO.
6. Mannitol 1-2g/kg IV.
7. Recheck intraocular pressure hourly.
8. Topical pilocarpine 1% to 2%, one drop four times daily once intraocular
pressure is below 40 mmHg.
9. Consult ophthalmology.
Acute angle closure glaucoma is a condition that we will all probably encounter
at some point during our careers. Although non-ocular symptoms may be the
patient’s main complaints, acute angle closure glaucoma should always come to
mind in the patient with abdominal pain and/or headache. Asking the patient
about ocular symptoms and doing a quick exam of the patient’s eyes takes very
little time, and may save the patient’s vision. It is our job to remember this
the next time we encounter a patient who may potentially have acute angle
closure glaucoma.
References:
1. Dargin JM, Lowenstein RA. “The Painful Eye.” Emergency Medicine Clinics of
North America 26.1 (2008): 199-216.
2. Dayan M, Turner B, McGhee C. “Lesson of the Week: Acute angle closure
glaucoma masquerading as systemic illness.” British Medical Journal 313 (1996):
413-415.
3. Tintinalli JE, Kelen GD, Stapczynski JS. Emergency Medicine: A Comprehensive
Study Guide, 6th edition. New York: McGraw-Hill, 2004.
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Posted: Sunday, April 12, 2009