Massive cerebellar infarction caused by spontaneously isolated posterior inferior cerebellar artery dissection: A case report

Abstract

BACKGROUND

Diagnosing posterior inferior cerebellar artery dissection (PICAD) using radiological images is challenging. Massive cerebellar infarctions resulting from spontaneous, isolated PICAD are rare, and the associated clinical, imaging, and treatment options remain unclear.

CASE SUMMARY

A 39-year-old man was admitted for dizziness and unstable gait for two days. Physical examination revealed decreased right-limb muscle strength and right-sided ataxia. Brain magnetic resonance imaging (MRI) showed a massive acute right cerebellar infarction, but other modalities, including head and neck computed tomographic angiography (CTA) and magnetic resonance angiography (MRA), showed no obvious abnormalities. High-resolution vessel wall MRI (HR-VW-MRI) revealed right PICAD. The patient was diagnosed with massive cerebellar infarction caused by PICAD and active conservative treatment was initiated. The initial PICAD lesion disappeared 1.5 months after discharge, after which the patient experienced only slight weakness in his right limb for three months.

CONCLUSION

Since MRA and CTA may fail to identify PICAD, HR-VW-MRI is key in diagnosis and follow-up evaluation. Aggressive medication may be effective and safe for treating PICAD.

Key Words: Posterior inferior cerebellar artery dissection; Clinical features; High-resolution vessel wall magnetic resonance imaging; Massive cerebellar infarction; Case report

Core Tip: Diagnosis of posterior inferior cerebellar artery dissection (PICAD) can be challenging with conventional imaging methods like magnetic resonance angiography or computed tomographic angiography. High-resolution vessel wall magnetic resonance imaging is crucial for accurate diagnosis and follow-up. Aggressive conservative treatment may be effective and safe for managing PICAD, with significant recovery observed in the patient within 3 months.

INTRODUCTION

Cerebral artery dissection (AD) refers to a condition that causes blood to enter the blood vessel wall through a damaged tunica intima, resulting in dissection and intramural hematomas, arterial stenosis or occlusion, and even false aneurysm[1]. Cerebral AD can be spontaneous or traumatic. Neck trauma, yoga, severe cough, cervical massage[2], and golf can cause traumatic cerebral AD[3]. Spontaneous AD may be associated with congenital vascular wall structural abnormalities or hereditary abnormalities of elastic tissue and collagen. Patients with posterior inferior cerebellar artery dissection (PICAD) frequently experience subarachnoid hemorrhage (SAH)[4], and isolated PICAD is rare[5]. In addition, detecting PICAD on radiological images is difficult due to the small diameter of the vessel[6].

CASE PRESENTATION

Chief complaints

A 39-year-old man was admitted for dizziness and an unstable gait, which had been persisting for two days, and right limb weakness that was first noticed 10 hours prior in June 2021.

History of present illness

Massive right cerebellar infarction was observed on the head computed tomography (CT; Figure 1A) with no obvious abnormalities on craniocervical CT angiography (CTA; Figure 1B and C).

Figure 1 Neuroimaging findings of the patient during hospitalization. A: Head computed tomography (CT) on admission showing a massive low-density lesion in the right cerebellar hemisphere and vermis; B and C: Craniocervical CT angiography on admission shows no obvious arterial stenosis or occlusion; D-I: Magnetic resonance imaging (MRI) showing a massive acute infarction in the right cerebellar hemisphere and vermis and lesions with limited diffusion on diffusion-weighted imaging (D, E; arrows), hypointensity on the apparent diffusion coefficient map (F, arrow) and T1-weighted imaging (T1WI), and (G) hyperintensity on T2-weighted imaging (H, arrow) and fluid-attenuated inversion recovery MRI (I, arrow); J: Blood supply area of the posterior inferior cerebellar artery (PICA); the dark blue area is the arterial territory of the lateral branch of the PICA, and the light blue area is that of the medial branch.

History of past illness

The patient had a history of alcoholic liver disease and smoking (averaging 10 cigarettes per day), but had no history of significant alcohol consumption.

Personal and family history

Additionally, he had no history of hereditary disease.

Physical examination

Physical examination revealed decreased muscle strength in the right limb (5-/5), a positive finger-to-nose test, rapid alternating hand movement, heel-knee-tibia test on the right side, and Romberg’s sign.

Laboratory examinations

Laboratory analysis showed weakly positive fecal occult blood test results and elevated levels of gamma-glutamyl transpeptidase (138 U/L), ferritin (380.0 ng/mL), and protein C (131.00%).

Imaging examinations

Chest CT showed scattered exudative lesions in both lungs, and bilateral lower lobes were clearly visible. Abdominal CT showed mild fatty liver, and echocardiography, contrast transcranial Doppler, contrast echocardiography, and 24-hour dynamic electrocardiography revealed obvious abnormalities. Furthermore, 1.5-T magnetic resonance imaging (MRI) showed a massive acute right cerebellar infarction (Figure 1D-I) in the area supplied by the PICA (Figure 1J)[7], with no obvious abnormalities on gadolinium-contrast magnetic resonance angiography (MRA) (Figure 2A). Moreover, 3.0-T high-resolution vessel wall (HR-VW) MRI showed right PICAD (Figure 2B-D).

Figure 2 Findings on magnetic resonance angiography, high-resolution vessel-wall magnetic resonance imaging, and follow-up imaging findings. A: Brain magnetic resonance angiography (MRA) shows no obvious abnormalities; B-D: High-resolution vessel-wall magnetic resonance imaging (HR-VW MRI) reveals a crescent-shaped enhanced lesion in the vascular wall of the posterior inferior cerebellar artery (arrows); E and F: 1.5-month follow-up HR-VW MRI demonstrating complete disappearance of the lesion.

FINAL DIAGNOSIS

A massive cerebellar infarction caused by spontaneously isolated PICAD.

TREATMENT

Active conservative treatment was initiated after surgery was ruled out, which included the administration of intravenous Ginkgo biloba extract (GBE). Despite slight weakness, the patient was discharged on day 16 with clopidogrel 75 mg/day for 14 days, GBE tablets for one month, aspirin 0.1 g/day for 1.5 months, and citicoline capsules and atorvastatin for 1.5 months.

OUTCOME AND FOLLOW-UP

A follow-up HR-VW MRI at 1.5 months showed that the initial PICAD had disappeared (Figure 2E and F). At the three-month follow-up, the patient experienced slight weakness in the right limb while walking quickly.

DISCUSSION

Here, we report a rare case of a patient with a massive cerebellar infarction caused by spontaneously isolated PICAD. There were no obvious precipitating factors such as trauma, neck massage, or vigorous exercise, and no warning signs of AD such as head or neck pain. Notably, PICAD-related stroke is difficult to diagnose and can easily be misdiagnosed using conventional MRA or CTA.

Occipital headache, headache, or nuchal rigidity are common warning signs of dissection[2,8-11]; however, approximately 20% of patients have no warning symptoms before stroke[1]. Our patient experienced sudden vertigo, which was possibly related to posterior circulation ischemia or cerebellar infarction. PICAD can manifest with other symptoms, such as nausea, vomiting, confusion[2], seizure[10], postural imbalance, and Wallenberg syndrome[12], depending on the extent and location of the infarction or hemorrhage. The clinical manifestations of spontaneously isolated PICAD are similar to those of intracranial vertebral AD. The clinical course of PICAD is relatively stable and benign[12]. Only a few reports of isolated PICAD have been published (Table 1). Most cases of PICAD present with secondary SAH or intraventricular hemorrhage[2,8,10]; there are few reports of ischemic stroke in cases of PICAD[10,11], and fewer cases of massive cerebellar infarction. Edema secondary to massive cerebellar infarction can compress the fourth ventricle and cause acute obstructive hydrocephalus, resulting in intracranial hypertension, cerebral hernia, and even death. Effective and timely treatment can help control these symptoms.

Table 1 Clinical and imaging characteristics, diagnostic methods, treatment, and outcomes of stroke caused by posterior inferior cerebellar artery dissection.

Patient	Age (years) and sex	Predisposing causes and main symptoms	Methods of diagnostic imaging	Types of stroke caused by PICAD	Main treatment	Outcome and follow-up
Patient 1[2]	40-year-old woman	Sudden headache during sexual intercourse, followed by a loss of consciousness	DSA revealed right PICAD	CT showed SAH	Endovascular treatment	No neurological symptoms at discharge; 3-year DSA showed complete occlusion of the AD
Patient 2[2]	66-year-old man	History of hypertension and development of a severe headache accompanied by vomiting and confusion	DSA demonstrated right PICAD	CT showed diffuse SAH with ventricular enlargement	Injection of a mixture of histoacryl and lipiodol	Neurological examination 3 years later was normal, and DSA showed that the AD was completely occluded
Patient 3[2]	46-year-old woman	Vertigo and diplopia after a cervical manipulation, followed by a headache with nuchal rigidity	DSA showed right PICAD	CT and MRI revealed an SAH with cerebral ischemia in the territory of the PICA	Non-surgical treatment	Diplopia at discharge. DSA at 4 months displayed unchanged PICAD. No further symptoms observed at the 2-year follow-up
Patient 4[2]	71-year-old woman	Sudden unconsciousness	DSA revealed left PICAD	CT showed SAH and intraventricular hemorrhage	Occlusion of the pseudoaneurysm was performed with coils	Intense weakness, diplopia, and cognitive impairment 3 years after therapy
Patient 5[2]	42-year-old woman	Intense posterior headache, dizziness, and vomiting after cervical manipulation	DSA revealed right PICAD	CT revealed right cerebellar infarction	Intravenous heparin for 2 weeks	Clinical state improved considerably. The patient was free of symptoms after 2 years
Patient 6[8]	63-year-old man	Severe acute occipital headaches and vomiting	DSA revealed left PICAD	CT showed a massive SAH in the posterior fossa	Aneurysmorrhaphy and a wrapping procedure	Symptoms resolved after surgery
Patient 7[8]	28-year-old man	Sudden onset of vertigo and numbness of the left hemiface	DSA revealed left PICAD	Not mentioned	Conservative treatment, followed by endovascular treatment	Freedom from neurological symptoms at the 5-month follow up
Patient 8[8]	33-year -old woman	Sudden severe headaches after transient unconsciousness	DSA showed a left PICAD	CT revealed SAH	PICAD was trapped and resected	At 5 months, neurological examination revealed slightly weak voice
Patient 9[9]	48-year-old man	Severe, throbbing headache	MRI revealed a right PICAD	No infarctions or hemorrhages	Conservative therapy	Headache rapidly improved. MRI showed almost-resolved PICAD 4 months later
Patient 10[10]	52-year-old woman	Nausea, vomiting, vertigo, gait instability, and headaches for 1 day	CTA showed focal stenosis in the left PICAD	CT and MRI showed an extensive left cerebellar hemisphere infarct	Aspirin, statin, and antihypertensive medication	Full recovery within 3 months; 7-, 12- and 18- month CTA showed the beaded appearance of the left PICA
Patient 11[10]	60-year-old woman	Acute headaches, nausea, vomiting, loss of consciousness, and seizure	CTA and DSA showed a left PICAD	CT revealed SAH, intraventricular hemorrhage, and hydrocephalus	Endovascular treatment for PICAD	1-year follow-up CTA showed minimal decrease in size of PICAD, accompanied by mild cognitive impairment
Patient 12[11]	41-year-old man	Mild left occipital headache, followed by dizziness, nausea, and vomiting	DSA detected a PICAD	MRI revealed infarction in the left cerebellar hemisphere	Intravenous edaravone and oral ibudilast	10-week follow-up MRA indicated resolution of the PICAD, and symptoms improved

AD: Dissecting aneurysm; CT: Computed tomography; CTA: Computed tomographic angiography; DSA: Digital subtraction angiography; MRI: Magnetic resonance imaging; MRA: Magnetic resonance angiography; PICA: Posteroinferior cerebellar artery; PICAD: Posteroinferior cerebellar artery dissection; SAH: Subarachnoid hemorrhage.

Diagnosing PICAD is often difficult and requires close and repeated imaging evaluations. Here, PICAD was identified by its characteristic origin from the distal vertebral artery (VA) and its unique trajectory around the medulla oblongata, to supply the inferior cerebellum (Figure 1J). In contrast, the VA primarily supplies the medulla oblongata, pons, and dorsal portions of the cerebellum. On HR-VW MRI, the PICA can be distinguished by its smaller caliber and distinct course compared with the larger VA. Therefore, differentiation is primarily based on the anatomical relationships, blood supply regions, and specific imaging features. PICAD should be considered a differential diagnosis in patients with of PICA territory infarction (Figure 2).

Visible signs of PICAD on CTA or MRA are rare, as in our patient, which implies that such findings may relate to the imaging processing technology or occur coincidentally. The PICA is the largest intracranial branch of the VA; however, owing to its small diameter and curvature, conventional MRI cannot easily detect intramural hematomas (IMH). HR-VW MRI plays a key role in the diagnosis and subsequent evaluation of curative effects. T1-weighted and dark-blood HR-VW MRI can be used to identify micro-IMHs in the PICA, thus making these techniques important for the diagnosis of AD in young adults. Furthermore, MRI has the advantage of soft-tissue contrast, which is helpful for showing a crescent-shaped IMH in the false lumen[13]. HR-VW MRI can detect IMH and improve the non-invasive diagnostic accuracy of isolated PICAD[13]. HR-VW MRI is a high-resolution, multiparametric MRI sequence that directly visualizes the intracranial artery wall and its pathological changes, allowing for better pathology characterization[14].

HR-VW MRI is valuable in distinguishing between atherosclerotic and non-atherosclerotic intracranial vascular lesions. Wall hematoma is the most common direct sign on HR-VW MRI in patients with craniocervical AD, whereas intimal flap or double-lumen signs are the least common. The detection rates of HR-VW MRI for IMH, aneurysmal dilatation, and intimal flaps (double-lumen sign) are 86%, 71%, and 47%, respectively[15]. In this patient, a crescent-shaped IMH was detected, but the double-lumen sign was not obvious. Furthermore, double-lumen sign, aneurysm dilatation, and IMH can gradually disappear during recovery, and the HR-VW-MRI findings of PICAD can show dilated, thickened, or string-of-beads changes in the outer diameter of blood vessels with IMH, which indicate obvious enhancement[16].

Owing to the unique signs of AD on digital subtraction angiography (DSA), including aneurysmal dilatation or the string-of-beads sign, the double-lumen sign, or an intimal flap[17], DSA is the gold standard for diagnosing AD[10]. However, DSA cannot display the vascular wall directly, which limits its use for vascular-wall dissection diagnosis[13]. Less than 10% of patients show double-lumen signs on DSA, and AD commonly presents with non-specific lumen stenosis with or without pseudoaneurysms, making the diagnosis of dissection difficult[18].

CONCLUSION

In conclusion, PICAD should be considered in patients with acute cerebellar infarction in the blood supply area of the PICA, even when no clear precipitating factors or warning signs are present. HR-VW MRI is crucial for diagnosis and follow-up evaluation. The pathogenesis (particularly congenital vascular wall structural abnormalities or hereditary abnormalities of the elastic tissue and collagen) and appropriate treatment of PICAD require further investigation.

ACKNOWLEDGEMENTS

We would like to thank the “Double-First Class” Application Characteristic Discipline of Hunan Province (Pharmaceutical Science) for its support.