Subtle visual impairment caused by temporoparietal infarction: a case report

Introduction

Patients with various illnesses present to emergency departments (EDs), which can lead to overcrowding that prevents clinicians from providing each patient with sufficient attention.^1,2 For example, Chatterjee et al. reported that overcrowding in the ED causes treatment delays for patients with stroke ³ ; many other studies have shown that overcrowding reduces the quality of care and increases medical errors.^4–8 Additionally, patient complaints are often ambiguous; patients often present with somatization disorders, rather than actual physical problems. These factors can cause work-related fatigue and mental distraction in ED clinicians. ⁹

Neuromuscular diseases have long been regarded as psychiatric diseases (e.g., conversion disorders). ⁹ Because the diagnostic methods for these diseases have improved in recent years, they are no longer considered simple psychiatric problems. However, mild paresthesia can lead to misdiagnosis by clinicians. In the challenging ED environment, clinicians must strive to avoid missing minor signs of illness. Here, I present a case in which the diagnosis could easily have been overlooked because of the patient’s vague, non-specific symptoms and a few coincidental events.

Case report

A man in his 50 s visited the ED at around 12:40, stating that he had experienced discomfort while driving at approximately 14:00 on the previous day. Although the discomfort was difficult to describe, the patient reported that the distance from his car to the car behind him felt shorter than usual, and he had experienced vague distress when changing lanes. For several reasons, the patient did not consider the symptoms serious; therefore, he visited the ED approximately 23 hours after symptom onset.

The patient did not have a long-term history of medication use; however, he had been incidentally diagnosed with diabetes mellitus during a routine test performed at a local clinic on the day before symptom onset. Thus, on each of the two days preceding his visit to the ED, the patient had taken diabetes medication for the first time in his life (oral glimepiride 1 mg once daily and oral metformin hydrochloride 0.5 g once daily); he had not taken either medication on the day that he visited the ED. He also stated that he had not driven in the preceding 2 weeks (Figure 1). The patient thought that his poor driving was not the result of illness; he speculated that it was a side effect of the medication he had begun taking on the previous day, or that it was related to his brief hiatus from driving. Importantly, he did not experience any other discomfort while driving. However, on the following day, he experienced the same symptoms while driving; therefore, he visited the ED.

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Figure 1.

Timeline of events in this case.

The patient’s blood pressure was 180/90 mmHg, his pulse was 95 beats/minute, his respiratory rate was 18 breaths/minute, and his body temperature was 37.3°C. His white blood cell count, hemoglobin, platelet count, prothrombin time, activated partial thromboplastin time, and international normalized ratio values were 7930/µL, 15.7 g/dL, 144,000/µL, 11.4 s, 30.5 s, and 1.04, respectively. His other laboratory findings were as follows: serum glucose, 358 mg/dL; erythrocyte sedimentation rate, 10 mm/hour; total cholesterol, 170 mg/dL; triglycerides, 139 mg/dL; high-density lipoprotein cholesterol, 27.7 mg/dL; low-density lipoprotein cholesterol, 115 mg/dL; and hemoglobin A1c, 9.1%. The serum glucose and hemoglobin A1c levels were high; however, no other abnormal findings were observed. An emergency medicine (EM) resident performed the initial physical and neurological examinations. The patient's Glasgow Coma Scale score was 15, both upper and lower motor grades were 5 (Medical Research Council Scale for Muscle Strength), and all sensations were intact. No other neurological abnormalities were noted. Reassessment of the patient by the attending EM physician revealed that the driving-related discomfort only occurred when the patient changed to the left lane. Therefore, a more detailed neurological examination of the visual fields was performed; slight restriction was observed in the left visual field. These results were sufficient to alert the clinicians of the need for further evaluation; brain magnetic resonance imaging (MRI) was performed (Figure 2). The results confirmed a right temporoparietal infarction; accordingly, the patient was hospitalized and antiplatelet therapy was initiated. His symptoms improved and he was discharged. Thus far, the patient has not returned for outpatient follow-up, presumably because his symptoms were mild.

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Figure 2.

Brain magnetic resonance imaging findings. (a) Diffusion-weighted image. (b) Apparent diffusion coefficient assessment. The results show high diffusion-weighted image signal and low apparent diffusion coefficient signal in right middle cerebral artery territory

This report was written in accordance with the CARE guidelines. ¹⁰

Discussion

Temporoparietal infarction causes symptoms such as unilateral weakness or numbness, facial droop, speech deficits, emotional changes, and visuospatial impairment.^11,12 Some signs are easily recognized; however, a few signs can be missed if a patient is not carefully examined. In my hospital, overlapping history-taking and physical examination by an EM resident and then an attending EM physician has been instituted to overcome this issue. This “spider web” method of care involves initial examination by the EM resident and subsequent reporting to the attending EM physician, who conducts a second examination based on the resident’s report. In the present case, the patient did not have any motor weakness; after arriving at the ED, he reported that his symptoms had improved. History-taking revealed many possible causes other than cerebral infarction, such as the brief hiatus from driving or the onset of symptoms on the day after initiation of diabetes treatment. Additionally, because the patient only experienced slight discomfort when changing lanes and no symptoms occurred in other settings, his symptoms could have been dismissed by the medical team. In many hospitals, the availability of highly developed medical equipment can lead to the perception that history-taking and physical examination are cumbersome processes.^13,14 However, not all EDs have access to MRI equipment; from a medical or cost perspective, even if MRI equipment is available, it is not appropriate to perform such examinations on each patient. Efforts to identify hidden diseases through meticulous history-taking and physical examination remain important.

Conclusion

In the time-sensitive and overcrowded ED environment, the overlap of a few coincidental events can lead to misdiagnosis in patients with subtle symptoms. Furthermore, as the ED environment becomes busier, history-taking and physical examination approaches become more important. An emphasis on accurate diagnosis through more meticulous history-taking and physical examination can help establish appropriate care in the early stages of disease.