Tension pneumocephalus: case report and review

A Rare Case of Non-traumatic Tension Pneumocephalus Following a Lumbar Puncture: Unusual Complications of a Common Procedure

Tension pneumocephalus is a rare but severe complication characterized by intracranial air accumulation, leading to increased intracranial pressure (ICP). While it is most commonly associated with trauma, surgical interventions, tumors, or infections, spontaneous cases related to skull base defects and cerebrospinal fluid (CSF) leaks are uncommon. We present what we believe to be one of the first reported cases of tension pneumocephalus following a diagnostic lumbar puncture (LP) in an otherwise healthy individual with no predisposing history, prior history of skull base trauma or surgery. The patient was a 66-year-old female who presented with altered mental status. Initial non-contrast CT brain scans showed no evidence of pneumocephalus, though incidental left sphenoid sinus opacification was noted. Following the LP, the patient's neurological symptoms worsened, and subsequent imaging revealed tension pneumocephalus. Further evaluation confirmed a focal dehiscence in the posterolateral wall of the left sphenoid sinus, with herniation of brain tissue consistent with a lateral sphenoid encephalocele. We hypothesize that the LP induced a negative ICP gradient, precipitating a CSF leak and ingress of air through the skull base defect. As intracranial air pressure increased, the encephalocele likely functioned as a one-way "ball-valve" mechanism, exacerbating the tension pneumocephalus. This case highlights the potential for routine diagnostic procedures to result in serious complications in patients with undiagnosed skull base defects. Detecting subtle encephaloceles and areas of skull base dehiscence can be difficult on non-contrast imaging, emphasizing the need for high clinical suspicion, especially when evaluating for CSF leaks. Multidisciplinary management and early recognition of such anatomical vulnerabilities are critical in preventing life-threatening complications associated with tension pneumocephalus.

Sphenoidal pneumosinus dilatans associated compressive optic neuropathy: A case series of four adolescent patients

Visual impairment caused by pneumosinus dilatans (PSD) among adolescents is a rare condition, which is associated with a high blinding rate due to the lack of clinical manifestations and effective treatment. The use of magnetic resonance imaging (MRI) and computed tomography (CT) may be helpful in diagnosis of PSD, and the endoscopic transnasal optic nerve decompression (ETOND) can improve the vision of PSD patients with visual impairments. This case series report detailing the diagnosis and treatment of visual impairments caused by PSD has improved clinicians' understanding of this disease and helped reduce misdiagnoses and missed diagnoses. This article also highlighted the efficacy of this less invasive technique in managing optic nerve compression caused by sphenoidal pneumosinus dilatans (SPSD) in pediatric patients. In addition, this report proposed a novel aspect to explore the etiology of PSD and suggested the significance of proper terminology use when describing different PSD conditions, as well as possible future mechanisms explorations.

Sudden-onset, non-traumatic large volume pneumocephalus following presentation of acute bacterial meningitis

A man in his 30s, with sinonasal undifferentiated carcinoma status post resection 6 years prior, presented with acute onset of fever, headache and altered mentation. The patient was diagnosed with bacteremia and meningitis due to Streptococcus pneumoniae A standard antibiotic and corticosteroid regimen was started. Brain MRI showed an encephalocele abutting the superolateral nasopharynx mucosa. After several days of clinical improvement, the patient's mental status and headache acutely relapsed. A CT head venogram showed a large volume pneumocephalus originating from the region of a surgical defect. Management included external ventricular drain placement followed by right pterional craniotomy with skull base packing. Skull base defects increase the risk of life-threatening conditions such as bacterial meningitis and pneumocephalus. It is crucial for clinicians to be aware of the possibility of cranial surgical defects developing years after surgery.