What caused arm numbness and epistaxis in this man?

May 1, 2007

A 38-year-old man presented to the emergency department after experiencing the sudden onset of right upper extremity numbness, heaviness, and loss of coordination, which resolved after 20 minutes. He had 2 similar episodes 19 years and 11 years earlier. Diagnostic evaluation (including MRI of the brain, carotid Doppler ultrasonography, and echocardiography) at the time of the second episode was unrevealing.

A 38-year-old man presented to the emergency department after experiencing the sudden onset of right upper extremity numbness, heaviness, and loss of coordination, which resolved after 20 minutes. He had 2 similar episodes 19 years and 11 years earlier. Diagnostic evaluation (including MRI of the brain, carotid Doppler ultrasonography, and echocardiography) at the time of the second episode was unrevealing.

The patient reported a lifelong history of intermittent epistaxis for which he had undergone multiple nasal endoscopies as well as silver nitrate cauterization and packing. A previous CT scan demonstrated bilateral maxillary sinus mucosal thickening. Prior antibiotic and corticosteroid treatment for sinusitis failed to alleviate his epistaxis.

The patient was taking no medications and denied drug allergies. He was originally from Jamaica. Occasionally, he smoked cigarettes and marijuana and drank alcohol. His family history was positive for diabetes mellitus, hypertension, and seizure disorder in a brother.

On physical examination, the patient's vital signs were within normal limits. He had tinea versicolor over much of his body and a small red lesion under 1 fingernail that was difficult to see because of his dark skin pigmentation. Heart and lung sounds were normal on auscultation. Findings from abdominal and neurological examinations were normal.

Laboratory studies revealed a reduced hematocrit of 26%. Results of hemoglobin electrophoresis were normal. An MRI scan of the brain demonstrated evidence of old infarctions of the left precentral and postcentral gyri but no acute findings. MR angiography of the head and neck vessels yielded normal results. An echocardiogram showed prompt appearance of agitated normal saline contrast in the left atrium after intravenous injection, suggesting a patent foramen ovale.

The patient's posteroanterior (PA) and lateral chest radiographs obtained on admission are shown below (Figure 1).

How would you interpret these findings? How would you proceed?

Discussion on next page.

Making the diagnosis

PA and lateral chest radiographs demonstrated a 4-cm mass in the superior segment of the left lower lobe of the lung (Figure 1). The mass was contiguous with 2 tubular structures extending from the hilum, best visualized on the lateral radiograph. The mass was solid, with no cavitation or air-fluid level. The lungs were otherwise clear, and there was no lymphadenopathy or pleural effusion. The heart size was normal.

The differential diagnosis of a solitary pulmonary mass is lengthy; however, there are relatively few possibilities in a 38-year-old man. Bronchogenic carcinoma must be considered in this patient, even though it is somewhat unlikely given his young age and limited smoking history.

Metastatic disease is a possibility, although the presence of a single large pulmonary mass and no history of a primary cancer suggests otherwise. Other pulmonary neoplasms, such as hamartoma and carcinoid tumors, are possible. Because the patient had systemic symptoms, a vasculitis (such as Wegener granulomatosis) should also be considered.

However, careful inspection of the patient's lateral chest radiograph revealed an important clue to the diagnosis: the tubular structures extending from the mass to the hilum strongly suggested a pulmonary arteriovenous malformation (AVM). CT scans of the chest with and without intravenous contrast demonstrated rapid opacification of the mass in phase with pulmonary arterial enhancement, which confirmed the diagnosis of AVM. Contrast-enhanced CT scans specifically showed a single large feeding artery arising from the left main pulmonary artery and a single large draining vein connected to the left superior pulmonary vein (Figure 2).

Because of the patient's history of recurrent epistaxis and the identification of buccal mucosa telangiectases on repeated physical examination, hereditary hemorrhagic telangiectasia (HHT) (also known as Rendu-Osler-Weber syndrome) was diagnosed. This inherited syndrome is characterized by AVMs and telangiectases in the lungs, skin, mucous membranes, and other organs.

The patient's multiple transient ischemic attacks (TIAs) and old cerebral infarctions seen on MRI were presumed to be a result of paradoxical emboli through the AVM. Based on the initial evaluation, percutaneous catheter closure of the patent foramen ovale to prevent further paradoxical emboli was considered. However, postprocedure treatment with aspirin and clopidogrel would be required and might aggravate the patient's already tenuous epistaxis. He subsequently underwent transcatheter coil embolization of the pulmonary AVM, with a good postprocedure angiographic result.

Discussion

The term "pulmonary arteriovenous malformation" is used to describe a spectrum of abnormal vascular communications between pulmonary arteries and veins.1 The spectrum ranges from microscopic communications, which are not visible on imaging studies, to large complex malformations.1

Roughly 60% of pulmonary AVMs are congenital. The remaining 40% usually are secondary to trauma or are associated with hepatopulmonary syndrome. Pulmonary AVMs typically enlarge slowly and are not diagnosed until adulthood; however, enlargement can be rapid in some cases. About 80% are classified as simple AVMs, which consist of a single dilated vascular sac with a single feeding artery and a single draining vein (as in the case presented here).2

The remaining 20% are complex AVMs, with multiple feeding arteries or draining veins. Feeding arteries and draining veins are usually contiguous with the pulmonary vascular system, but in rare cases, they may connect to the systemic circulation.3

Small (less than 2 cm) AVMs are usually asymptomatic. Larger lesions may result in anatomic right-to-left shunts, which may be complicated by a reduction in arterial oxygen saturation, polycythemia, or paradoxical emboli.1 Associated signs and symptoms include hemoptysis, dyspnea, chest pain, palpitations, and cyanosis. Unfortunately, patients may remain asymptomatic until they present with serious complications, including stroke/TIA, brain abscess, or pulmonary hemorrhage.

Stroke/TIA can result from either paradoxical embolization or secondary polycythemia. Brain abscess results from paradoxical septic embolization. Pulmonary hemorrhage is a result of AVM rupture. Because pulmonary AVMs are typically subpleural, rupture can present with hemothorax.

The classic radiographic finding of a pulmonary AVM is a well-defined nodule or mass with 1 or more adjacent tubular opacities that extend to the pulmonary hilum.4 Lobulation of the nodule or mass may also be evident. Two thirds of AVMs are found in the lower lobes.

About 35% to 60% of patients with pulmonary AVM have multiple lesions, which can be bilateral.4 The presence of multiple lesions usually indicates HHT. It is important to remember that the characteristic tubular opacities (representing the feeding artery and draining vein) may not be apparent on the chest radiograph, particularly in small lesions. Thus, an AVM may simply appear as a nonspecific pulmonary nodule.

The classic unenhanced CT finding associated with pulmonary AVM is a serpiginous-shaped pulmonary nodule with vascular structures that connect the nodule to the arterial and venous pulmonary vessels.4 AVM can be diagnosed without intravenous contrast-enhanced CT in patients who present with classic features; however, the contrast allows for a more confident diagnosis and enhances the architecture of the lesion in 3-dimensional (3D) reconstructions of the image (Figure 3). Although 3D reconstructions are unnecessary for diagnosis, they play a potentially important role in planning embolotherapy, which is now considered first-line, definitive treatment for pulmonary AVM.2

Embolization can be performed with either coils or detachable balloons. While successful in most cases, this technique can partially or completely fail in up to 25% of patients.5 In addition to its role in diagnosing AVMs, CT is also used in monitoring small AVMs (which may grow over time) and in evaluating treated AVMs for the need for repeated embolization.6

The outcome in this case

Follow-up CT scans after 1 year demonstrated a small amount of residual aneurysm filling and a patent draining vein. The patient subsequently underwent a re-embolization procedure. Although he has had no further neurological events, he continues to experience epistaxis. His family members were screened for HHT.

Figure 1 - A well-circumscribed, smoothly marginated mass (asterisk) in the superior segment of the left lower lobe is evident in the posteroanterior and lateral chest radiographs. Note the 2 subtle tubular opacities (arrows) extending from the mass to the hilum, best visualized on the lateral radiograph.

References:

REFERENCES

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