Hemosiderosis of lower cranial nerves: A pitfall in difficult-to-wean tracheotomized patients – A case report

Abstract

Cerebral hemosiderosis is a condition resulting from recurrent or extensive intracranial hemorrhages, leading to hemosiderin deposition in central nervous system structures and affecting cranial nerves. The classic clinical triad includes sensorineural hearing loss, cerebellar ataxia, and pyramidal signs, with less frequent involvement of other cranial nerves. In our case however, we report a unique presentation of multiple lower cranial nerve involvement following a right-myelencephalic subarachnoid hemorrhage secondary to hemorrhagic ventricular effraction in a 58-year-old male patient. We aim to highlight the implications of atypical cranial nerve hemosiderosis on swallowing and tracheotomy weaning and demonstrate the importance of tailored rehabilitation approaches. The patient presented a coma after hemorrhagic stroke and was later diagnosed with hemosiderosis affecting cranial nerves IX, X, and XII, leading to severe dysphagia and delayed tracheotomy weaning. Magnetic resonance imaging with susceptibility-weighted sequence confirmed the diagnosis. Neurorehabilitation was adjusted to incorporate specific swallowing techniques addressing pharyngeal motor deficits. Despite the tracheotomy weaning delay (31 vs 12.75 days average), a specific adaptation of cervical posture during the swallowing, that is, anterior flexion combined with a rotation ipsilateral to the affected side helped to secure swallowing and promote tracheotomy weaning. This case emphasizes that hemosiderin deposits can affect cranial nerves beyond the typical vestibulocochlear nerve, possibly influenced by cerebrospinal fluid flow patterns near Magendie’s foramen. This case underscores the need for early diagnosis and tailored rehabilitation in cerebral hemosiderosis with atypical cranial nerve involvement to optimize functional outcomes. Further research is essential to guide management in such rare presentations.

Introduction

Cerebral hemosiderosis is a clinical entity occurring after recurrent or extensive episodes of intracranial hemorrhage. Depending on the cerebral hemorrhage localization, it can lead to intracellular and extracellular deposition of hemosiderin in the leptomeninges, spinal cord, and subpial tissue. The etiology of recurrent cerebral bleeding can vary from angiopathic diseases, such as cerebral amyloid angiopathy ¹ or nonamyloid-associated small vessel disease, ² vascular abnormalities, such as arteriovenous malformations or aneurysms, brain tumors, or acquired brain injury, such as traumatic brain injury, hemorrhagic stroke, or neurosurgical procedures. The involvement of the subarachnoid space leads to the hemosiderin infiltration of several anatomical structures that are in contact with cerebrospinal fluid (CSF), possibly leading to focal neurological deficits. The most common clinical phenotype of cerebral siderosis is characterized by a triad including hearing loss secondary to sensorineural damage (95%), cerebellar ataxia (88%) and pyramidal signs (46%). ³ Other clinical signs include cognitive impairment and other focal deficits, including cranial nerves. ⁴ Finally, superficial cerebral siderosis is often asymptomatic, reported in 0.2%–0.7% of brain magnetic resonance imaging (MRI) studies in the general asymptomatic population.^5–7

It has been hypothesized that several anatomical structures are more frequently affected due to the specific pattern of CSF flow that irrigates certain regions in priority and are thus continuously exposed to hemosiderin. ⁸ The predilection for the eighth cranial nerve may be explained by its long central glial segment, which permits greater hemosiderin deposition. ⁹ However, implications of the olfactory nerve (I) or the optic nerve (II), ¹⁰ extraocular nerve palsies (III, IV, and VI), ¹¹ and trigeminal neuropathy (V), ¹² have also been reported.

The gold standard for the diagnosis of superficial hemosiderosis of the central nervous system is magnetic resonance imaging, with the gradient-echo T2* or susceptibility weighted imaging and spin-echo T2-weighted sequences being the most sensitive for hemosiderin deposition. ⁷

Even though the implication of the vestibulocochlear nerve (VIII) is well described as part of the classic clinical triad of cerebral hemosiderosis, ¹ data on the implication of other cranial nerves remain scarce. We report here a unique case involving siderosis of multiple cranial nerves of the medulla oblongata, leading to swallowing deficits and impeding tracheotomy weaning after hemorrhagic stroke. We aim to increase awareness into identifying this complication following cerebral hemorrhage to appropriately guide early neurorehabilitation and tracheotomy weaning.

Case description

A 58-year-old right-handed male presented at the emergency department with altered state of consciousness. The initial assessment revealed a Glasgow Coma Scale score of 4/15, with bilateral fixed miosis. Cerebral computed tomography-scan showed a right frontal intraparenchymal deep hematoma, associated with ventricular blood effraction and mass effect resulting in an 18 mm midline shift to the left. An emergency decompressive craniectomy was performed for blood evacuation followed by the placement of an external ventricular drain. The patient was subsequently admitted intubated to the intensive care unit.

On the first evaluation by our mobile acute neurorehabilitation (ANR) team performed 3 days posthemorrhage and more than 24 h after sedation withdrawal. The Coma Recovery Scale–revised was assessed at 2, corresponding to coma (presence of abnormal posturing characterized by an extensive response of the left arm to a noxious stimulation and oral reflexive movement). Consecutive clinical bedside evaluations using the Motor Behaviour Tool–revised ¹³ identified subtle motor behavior signs indicating the presence of residual awareness of self and the environment, such as the defensive nonreflexive response to a noxious stimulation on the patient’s protected nipple. Therefore, a diagnosis of clinical cognitive–motor dissociation was retained. ¹⁴ After further investigation, several confounding clinical factors (i.e. pitfalls) hampering the detection of conscious perception were identified, including:

• a. Akinetic mutism due to the right frontal hemorrhagic lesion with contralateral frontal lobe compression.

• b. Arousal fluctuation attributable to the right thalamic lesion and mass effect to the contralateral thalamus.

• c. Probable tetraparesis related to the lesion of the motor fibres along their trajectory in the right internal capsule and to a clinically suspected transient left Kernohan–Woltman notch phenomenon (ipsilateral hemiparesis), ¹⁵ though no lesion was visible on MRI.

Twenty-three days after admission, a tracheotomy was performed, and the patient was transferred to our ANR unit to pursue ANR including tracheotomy weaning.

During the tracheotomy weaning, we encountered several difficulties. First, the patient exhibited difficulty in managing salivation that was partially controlled by anticholinergic agents. Second, speech therapy team reported atypical progression in swallowing rehabilitation, marked by insufficient laryngeal ascension and projection, hypopharyngeal salivary stasis and a significant deficit in evacuating them, ineffective cough, severe hypophonia with open rhinolalia clinically, discordant with the patient’s general neurological improvements, and with swallowing disorders caused by laryngeal deafferentation linked to the presence of tracheotomy. Phoniatric examination revealed a right vagus-nerve injury, resulting in right palatal droop, pharyngeal hypotonia, and right vocal cord immobility with incomplete vocal glottic closure. Additionally, a minor right hypoglossal nerve injury was noted indicated by slight right tongue deviation on protrusion.

A hemorrhagic or ischemic infarct of the medulla oblongata or a direct iatrogenic inferior cranial nerve injury, secondary to the right central jugular venous access, were ruled out after a joint review of MRI images with a senior neuroradiologist. However, a retrospective review of the MRI by our senior neuroradiologist revealed siderosis involving multiple cranial nerves in the medulla oblongata implicated in swallowing (Figure 1).

Figure 1.

Susceptibility weighted brain MRI sequence of the patient showing hemosiderin deposition on the right vagus (X – white arrows), glossopharyngeal (IX), and hypoglossal (XII) nerves; diagnosis was retrospectively confirmed by a senior neuroradiologist (V.D.).

Specifically, hemosiderosis of the right vagus nerve accounted for the vocal cord paralysis and pharyngeal motor impairment, while glossopharyngeal and hypoglossal nerve involvement explained the sensory deafferentation (contributed by other factors such as the prolonged presence of the tracheotomy tube and salivary stasis) and tongue deviation, respectively. This siderosis was attributed to the right myelencephalic subarachnoid hemorrhage (SAH) secondary to the intraventricular blood effraction.

This etiological diagnosis validated specific adaptations necessary in swallowing rehabilitation, in particular the use of the cervical posture of anterior flexion combined with right rotation to close the right pharyngeal space which was deficient. These strategies facilitated swallowing rehabilitation progress, enabling successful tracheotomy weaning 31 days posttracheotomy, as well as oral food resumption and improvement of salivary management. The patient was discharged to a neurological rehabilitation center after a 48-day stay in the ANR unit. Four weeks after discharge, the patient was able to eat mixed foods and drink liquids of normal consistency. The tongue deviation gradually resolved. However, due to persistent severe hypophonia 2 months later, a right vocal cord medialization using Renú Voice^® injection was performed, allowing the patient to regain a louder voice and enabling a diet of finely chopped foods.

Methods and ethical considerations

The neuroimaging of choice on admission was cerebral 3 Tesla MRI (Vida; Siemens Healthineers, Erlangen, Germany). A senior neuroradiologist evaluated all MRI-based neuroimaging including susceptibility weighted imaging. Clinical evaluation of the patient was performed by different certified examiners in a nonblinded way. Data were anonymized using the principles of the Health Insurance Portability and Accountability Act Safe Harbor Privacy Rule ¹⁶ conducted in compliance with the Swiss Federal Act on Research involving Human Beings, which waives ethical approval for case reports of <5 patients. Written informed consent for publication of anonymized patient information was obtained from the patient’s legally authorized representative, as the patient was deceased at the time of publication. The anonymized data supporting the findings of this study are available from the corresponding author upon reasonable request.

Discussion

This case study highlights a rare complication of cerebral hemosiderosis affecting multiple cranial nerves in the medulla oblongata following a right-myelencephalic SAH secondary to ventricular blood effraction. The case underscores the significance of recognizing cranial nerve involvement outside the classic vestibulocochlear nerve (VIII) injury, which is most often cited in cases of cerebral siderosis. ¹⁷ This atypical presentation involving the glossopharyngeal, vagus, and hypoglossal nerves led to complex swallowing rehabilitation challenges that contributed to a prolonged tracheotomy weaning period compared to standard cases in ANR unit (successful weaning of tracheotomy in 31 days, compared to the typical 12.75 days). ¹⁸

Typically, siderosis concerns long central glial segment nerves and those upper situated in the brainstem. ¹⁹ The clinical phenotype of cranial nerve siderosis encompasses sensorineural hearing loss, cerebellar ataxia, and pyramidal signs, with rare cases reporting unusual anatomical localizations, such as vagus or glossopharyngeal nerve involvement as seen here. We hypothesized that certain anatomical structures, specifically those adjacent to the medulla oblongata, may be particularly susceptible to hemosiderin deposition due to CSF flow patterns. Magendie’s foramen, a principal exit point for CSF from the ventricles to the subarachnoid space, could contribute to the selective deposition of hemosiderin in adjacent cranial nerves when blood enters this area. In this patient’s case, hemosiderin was observed on MRI around the right cranial nerves in the medulla oblongata, suggesting a distinctive pattern that could be influenced by CSF flow dynamics near Magendie’s foramen.

From a neurorehabilitation perspective, this case highlights the importance of adapting therapeutic strategies in response to the specific etiology of delayed weaning. Common causes of tracheotomy weaning delay include neurogenic causes (i.e. brainstem dysfunction, cranial nerve implicated in swallowing involvement) and local issues (i.e. excessive secretions, tracheal stenosis, chronic inflammation or infection at the tracheotomy site, poor airway clearance, sensitive deafferentation, and scarring or granulation tissue around the tracheotomy tube).^20,21 Hemosiderosis as a rare underlying cause should be considered when common etiologies are excluded, and standard rehabilitative measures fail to achieve expected progress in tracheotomy weaning in complex brain hemorrhage cases. The clinical examination is often challenging in the acute phase due to lack of patient collaboration, and thus diagnostic tools such as nasofibroscopy can aid in evaluating cranial nerve function in these cases.

The limitation of this study is the identification of a single subject. Nonetheless, the scarcity of comparative literature on medulla oblongata nerve siderosis suggests the importance to look for this complication more carefully.

Conclusion

This case aims to raise awareness of this rare condition and emphasizes the need to consider cranial nerve hemosiderosis in complex recovery cases post-hemorrhage and to adapt therapy accordingly. A high index of clinical suspicion, along with expert neuroradiologic assessment, is essential for establishing this diagnosis. Further studies are needed to deepen understanding and optimize rehabilitative approaches for similar cases.