Giant chronic subgaleal hematoma secondary to repetitive self-injurious head-banging in severe autism: A case report

Abstract

Background:

Subgaleal hematoma (SGH) is defined as hemorrhage within the potential space between the galea aponeurotica and the periosteum. While SGH is well recognized in the neonatal period, its occurrence beyond infancy is rare, and chronic or progressively enlarging SGH in adolescents is exceedingly uncommon.

Case Description:

We report a 16-year-old male with severe autism spectrum disorder (ASD) and longstanding repetitive self-injurious head-banging behavior who presented with a massive, progressively enlarging scalp swelling. Neuroimaging demonstrated a large extracranial collection confined to the subgaleal space, with mixed radiological characteristics consistent with acute, subacute, and chronic hemorrhage, and no associated intracranial pathology. Surgical exploration revealed a giant mixed-stage SGH associated with markedly hypertrophied scalp vessels. Complete evacuation, meticulous hemostasis with selective vessel ligation, dead-space reduction, and subgaleal drainage were performed, resulting in excellent clinical and cosmetic outcomes without recurrence.

Conclusion:

Repetitive self-injurious head trauma represents a rare but important etiology of giant chronic SGH in adolescents with severe ASD. Awareness of this mechanism is essential, as delayed recognition may lead to progressive enlargement and significant deformity. Timely surgical intervention can provide definitive management and durable resolution.

INTRODUCTION

Subgaleal hematoma (SGH) refers to hemorrhage occurring within the potential space between the galea aponeurotica and the periosteum of the skull.[2] This anatomical compartment contains loose areolar tissue and emissary veins, allowing blood to dissect freely across cranial sutures and accumulate in large volumes. Consequently, SGH may present with extensive scalp swelling and, in severe cases, significant cosmetic deformity or hemodynamic compromise.

SGH is most commonly described in the neonatal period, where it is typically associated with birth-related trauma, particularly vacuum-assisted or forceps delivery. Beyond infancy, however, SGH is distinctly uncommon. In older children and adolescents, reported etiologies include blunt head trauma, hair traction injuries, and underlying bleeding diatheses.[3,4] The majority of reported cases in this age group are acute and self-limited, resolving either spontaneously or with conservative measures.

Chronic or progressively enlarging SGH beyond infancy is exceedingly rare, with only isolated case reports requiring surgical intervention.[1,3] The underlying pathophysiological mechanisms are not fully understood but are thought to involve repeated microvascular injury, impaired resorption, or ongoing low-grade bleeding within the subgaleal space.

Individuals with severe autism spectrum disorder (ASD) represent a unique and underrecognized population at risk for occult traumatic injuries. Self-injurious behaviors, including repetitive head-banging, are reported in up to 40– 50% of individuals with ASD, particularly in those with severe cognitive and communication impairment.[6] Repetitive head-banging exposes the scalp and subgaleal tissues to recurrent low- to moderate-energy trauma that may go unnoticed for prolonged periods due to atypical pain perception and communication difficulties.[5]

Despite the frequency of self-injurious behavior in ASD, extracranial hemorrhagic complications such as SGH are rarely described. Delayed presentation and cumulative vascular injury may predispose to chronic hemorrhage rather than a single acute event. In this report, we describe a rare case of a giant chronic mixed-stage SGH in an adolescent with severe ASD secondary to repetitive self-injurious head-banging, highlighting the clinical presentation, radiological features, operative findings, and surgical management.

CASE PRESENTATION

Clinical presentation and examination

A 16-year-old male with severe ASD and profound communication impairment was referred to our neurosurgical service because of a progressively enlarging scalp swelling noted by caregivers over several months. The patient had a longstanding history of repetitive self-injurious behavior, predominantly characterized by frequent head-banging against hard surfaces. There was no history of a single high-impact traumatic event, recent infection, anticoagulant use, or known bleeding disorder.

According to the caregivers, the scalp swelling and head enlargement had been progressively developing over several months before presentation. The delay in definitive care was multifactorial, including profound communication impairment due to severe autism and a history suggestive of medical neglect. The caregivers reported prior evaluation at another facility where needle aspiration of the collection was performed, but without sustained improvement, and the swelling continued to enlarge thereafter. On presentation, the patient was hemodynamically stable. Neurological examination was limited due to poor cooperation but revealed no focal deficits. The most striking finding was a massive, diffuse scalp swelling involving the frontal, parietal, and occipital regions, resulting in marked distortion of the scalp contour as shown in Figure 1. The swelling was soft, fluctuant, and nontender, with intact overlying skin and no signs of erythema, ulceration, or infection. No palpable skull defect was identified.

Figure 1:

(a and b) Preoperative photographs demonstrating massive diffuse scalp expansion due to a giant chronic subgaleal hematoma. Two views are provided from different angles to better convey the three-dimensional extent of the deformity.

Laboratory investigations, including complete blood count, platelet count, prothrombin time, activated partial thromboplastin time, and international normalized ratio, were all within normal limits, effectively excluding an underlying coagulopathy.

Radiological evaluation

Noncontrast computed tomography (CT) of the head demonstrated a large extracranial fluid collection confined to the subgaleal space, extending widely across cranial sutures. The collection exhibited mixed attenuation values, with areas of hyperdensity interspersed with hypodense regions, consistent with hemorrhage of varying ages. There was no evidence of skull fracture, intracranial hemorrhage, extra-axial collection, or parenchymal injury.

The radiological appearance suggested a chronic process with superimposed episodes of more recent bleeding, correlating with the patient’s history of repetitive head trauma. Given the progressive enlargement, mixed-density features, and significant cosmetic deformity, conservative management was deemed unlikely to result in resolution.

Surgical management

Surgical intervention was planned to achieve definitive diagnosis, evacuation, and hemostasis. Under general anesthesia, a curvilinear scalp incision was made over the most prominent region of the swelling. Upon elevation of the scalp flap, a large subgaleal cavity was immediately encountered.

The hematoma demonstrated mixed-stage characteristics, consisting of chronic components with thick, dark, partially liquefied contents displaying a characteristic “engine-oil” appearance, subacute components with altered but still semi-fluid blood, and acute components with fresh hemorrhagic material. These findings confirmed ongoing and recurrent bleeding episodes rather than a single traumatic event.

The evacuated contents suggested a spectrum of blood degradation, consistent with accumulation over different time points (acute, subacute, and chronic components).

Of particular note was the presence of multiple markedly hypertrophied subgaleal vessels, several measuring up to approximately 1 cm in diameter, coursing within the hematoma cavity and along the inner surface of the scalp flap as shown in Figure 2. These vessels appeared fragile and were considered a likely source of recurrent bleeding. Careful bipolar coagulation and selective ligation of these abnormal vessels were performed to achieve meticulous hemostasis.

Figure 2:

Intraoperative photograph showing an unusually enlarged hypertrophied subgaleal/scalp vein encountered during evacuation. The surgeon’s finger is intentionally included as a size reference to highlight the vessel caliber (approximately 1 cm).

Intraoperatively, these vessels were judged to represent markedly hypertrophied native scalp/subgaleal veins rather than newly formed or anomalous vasculature. No specimen was submitted for histopathology because there was no clinical or intraoperative suspicion of malignancy or vascular tumor/malformation.

Complete evacuation of the hematoma was followed by thorough irrigation of the subgaleal space. After decompression, significant scalp redundancy and dead space remained, reflecting the chronic expansile nature of the lesion. Limited scalp trimming and dead-space reduction were therefore performed to restore normal contour and minimize the risk of recurrence. A closed subgaleal suction drain was placed, and the wound was closed in anatomical layers.

Postoperative course and follow-up

The postoperative course was uneventful. Drain output decreased progressively and was removed after satisfactory reduction. No postoperative complications such as infection, reaccumulation, or wound dehiscence were observed.

At follow-up visits, caregivers reported complete resolution of the scalp swelling and significant improvement in cosmetic appearance. There was no clinical evidence of recurrence at 6 months. Continued behavioral management strategies were reinforced to address the patient’s underlying self-injurious behavior.

DISCUSSION

SGH beyond the neonatal period is rare, and its presentation as a chronic, progressively enlarging lesion in adolescents is exceptionally uncommon. Most reported cases in older children and adolescents are acute and related to blunt trauma, hair traction injuries, or bleeding disorders.[3,4] Chronic SGH requiring open surgical evacuation has been described only sporadically.[1,3]

The present case illustrates a distinctive mechanism in which repetitive low- to moderate-energy trauma, rather than a single high-energy event, resulted in cumulative vascular injury and progressive hemorrhage. Repetitive head-banging in individuals with severe ASD may go unnoticed due to atypical pain responses and communication limitations, allowing pathological processes to evolve over extended periods.[5,6]

A particularly striking intraoperative finding was the presence of markedly hypertrophied subgaleal vessels. Such vascular changes are rarely emphasized in previously reported cases, which more commonly describe diffuse venous oozing rather than focal vascular enlargement.[3] We hypothesize that repeated mechanical stress and chronic inflammation led to pathological vascular remodeling, resulting in fragile, dilated vessels prone to recurrent bleeding. This mechanism parallels the neovascularization observed in chronic subdural hematomas and underscores the importance of direct surgical control of abnormal vessels.

Radiologically, SGH is characterized by an extracranial collection that crosses suture lines while remaining confined to the subgaleal space. Mixed-density features on CT should raise suspicion for hemorrhage of varying ages, particularly in patients with a chronic or progressive course. In individuals with neurodevelopmental disorders, SGH should be considered in the differential diagnosis of progressive scalp swelling even in the absence of a clear traumatic history.

Management strategies for SGH beyond infancy are not standardized. Conservative treatment may be appropriate for small, stable collections; however, progressive enlargement, mixed-stage hemorrhage, significant cosmetic deformity, or suspected ongoing bleeding is widely accepted indications for surgical intervention.[2,3] In the present case, open surgical evacuation allowed direct visualization and selective ligation of hypertrophied vessels, dead-space reduction, and restoration of normal scalp contour, resulting in durable resolution without recurrence.

With timely diagnosis of a smaller SGH, initial conservative care typically includes observation, head protection/avoidance of further trauma, and compression dressing when tolerated, with close follow-up to ensure stability. Percutaneous aspiration or drainage may be considered for symptomatic, tense, or enlarging collections; however, invasive interventions should be weighed against infection risk and recurrence. Operative evacuation is generally reserved for recurrent or progressively enlarging hematomas, failure of conservative measures, significant cosmetic deformity, or suspicion of ongoing bleeding – principles consistent with standard neurosurgical practice (e.g., Greenberg’s Handbook of Neurosurgery).

CONCLUSION

Giant chronic SGH is a rare but significant complication of repetitive self-injurious head-banging in adolescents with severe ASD. Recurrent microtrauma may lead to chronic hemorrhage, pathological vascular remodeling, and progressive enlargement. Surgical evacuation with meticulous hemostasis, dead-space reduction, and drainage provides definitive management and excellent outcomes. Awareness of this entity is essential for timely diagnosis and appropriate treatment in this vulnerable population.

Ethical approval:

Institutional review board approval is not required.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for their images and other clinical information to be reported in the journal. The patient understands that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

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