A 42-year-old woman from Mumbai presents with 3 days of progressive right eye pain, vision loss, and chemosis. Examination reveals proptosis, ophthalmoplegia (CN III and VI), and a dilated fixed pupil. Temperature is 37.2°C (afebrile). MRI shows a mass in the right cavernous sinus with enhancement. Serum ACE level is elevated. What is the most appropriate next step in management?

Explanation

## Clinical Diagnosis: Aseptic Cavernous Sinus Thrombosis (Sarcoidosis) **Key Point:** The afebrile presentation, elevated serum ACE, and imaging findings suggest **aseptic** (non-infectious) cavernous sinus thrombosis, likely secondary to sarcoidosis. Sarcoidosis is a granulomatous disorder affecting multiple organ systems, including the CNS and orbit. **High-Yield:** Differential diagnosis of cavernous sinus lesions: | Feature | Septic CST | Aseptic CST (Sarcoidosis) | Lymphoma | IgG4-RD | |---------|-----------|------------------------|----------|----------| | **Fever** | Yes (high) | No/Low-grade | No | No | | **Blood cultures** | Positive | Negative | Negative | Negative | | **ACE level** | Normal | ↑ (sarcoidosis) | Normal | Normal | | **CXR findings** | Normal | Hilar LAD, pulmonary infiltrates | Mediastinal mass | Fibrosis | | **Treatment** | Antibiotics + source control | Corticosteroids | Chemotherapy | Corticosteroids ± rituximab | **Clinical Pearl:** This patient is afebrile with no systemic signs of infection. Elevated ACE and imaging suggest sarcoidosis-related cavernous sinus involvement. Corticosteroids are the first-line treatment. ## Management Algorithm for Aseptic CST ```mermaid flowchart TD A[Afebrile Cavernous Sinus Lesion]:::outcome --> B{Elevated ACE?}:::decision B -->|Yes| C[Suspect Sarcoidosis]:::outcome B -->|No| D[Consider lymphoma, IgG4-RD, TB]:::outcome C --> E[Chest imaging: CXR/HRCT]:::action D --> E E --> F{Systemic findings?}:::decision F -->|Yes| G[Confirm diagnosis: biopsy if needed]:::action F -->|No| H[Empiric corticosteroids]:::action G --> I[Start IV methylprednisolone]:::action H --> I ``` ## Management Steps 1. **Corticosteroids** — IV methylprednisolone 1 g daily for 3–5 days, then oral prednisone taper - Rapid improvement in vision and ophthalmoplegia expected - Prevents permanent vision loss 2. **Systemic evaluation** — confirm sarcoidosis diagnosis: - CXR/HRCT chest (hilar lymphadenopathy, pulmonary infiltrates) - Serum ACE (already elevated) - Serum calcium, 24-hour urine calcium - Pulmonary function tests - Ophthalmology assessment 3. **Tissue diagnosis** — biopsy only if systemic findings are atypical or diagnosis uncertain (not needed acutely if clinical picture is clear) 4. **Long-term management** — oral corticosteroids ± steroid-sparing agents (azathioprine, methotrexate) for chronic control **Warning:** Do NOT start antibiotics in an afebrile patient with elevated ACE and no fever/leukocytosis. This delays appropriate corticosteroid therapy and risks permanent vision loss. **High-Yield:** Afebrile + elevated ACE + cavernous sinus involvement = think sarcoidosis first. Start corticosteroids and evaluate for systemic disease. [cite:Harrison 21e Ch 381; Robbins 10e Ch 28]