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Explain detaily about csf rhinorrhea from the above images book of dhingra ent mbbs
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Here is a detailed explanation of CSF Rhinorrhoea as covered in Dhingra's ENT (Chapter 29):
CSF Rhinorrhoea (Dhingra ENT - Chapter 29)
1. DEFINITION
Leakage of CSF (cerebrospinal fluid) into the nose is called CSF rhinorrhoea. The fluid may be:
- Clear (most cases)
- Mixed with blood - as seen in acute head injuries
2. PHYSIOLOGY
Understanding CSF physiology is key to understanding this condition:
- CSF forms a fluid jacket around the brain and spinal cord, acting as a buffer against sudden jerks
- Secreted by: Choroid plexuses in the lateral, third, and fourth ventricles
- Absorbed by: Arachnoid villi into the dural venous sinuses
- Arachnoid villi work as a one-way valve - CSF moves from subarachnoid space to blood, but not the other way
- Total volume: 90-150 mL
- Secretion rate: ~20 mL/hour (350-500 mL/day)
- Total CSF is replaced 3-5 times per day
- Normal CSF pressure at lumbar puncture: 60-250 mm H₂O
Important clinical note: CSF pressure rises on coughing, sneezing, nose blowing, straining at stool, and lifting heavy weights. These activities must be strictly avoided in cases of CSF leak or after repair.
3. AETIOLOGY
| Cause | Details |
|---|---|
| Trauma (most common) | Accidental or surgical. Surgical causes include: endoscopic sinus surgery, trans-sphenoidal hypophysectomy, nasal polypectomy, skull base surgery. In endoscopic sinus surgery, leak can be immediate or delayed |
| Inflammations | Mucocoeles of sinuses, sinonasal polyposis, fungal infections of sinuses, osteomyelitis - all can erode bone and dura |
| Neoplasms | Benign or malignant tumours invading the skull base |
| Congenital lesions | Meningocoele, meningoencephalocoeles, gliomas - all may have associated skull base defects |
| Idiopathic | Unknown cause with spontaneous leak |
4. SITES OF LEAKAGE
CSF reaches the nose through different routes depending on which fossa is involved:
- Anterior cranial fossa: Via (i) cribriform plate, (ii) roof of ethmoid air cells, or (iii) frontal sinus
- Middle cranial fossa: Follows injuries to the sphenoid sinus
- Temporal bone fractures: CSF reaches the middle ear → escapes via Eustachian tube into the nose → called CSF otorhinorrhoea
(Illustrated in Fig. 29.4 - showing sites: frontal sinus (a), ethmoid sinus (b), sphenoid sinus (c), Eustachian tube/temporal bone fracture (d))
5. DIAGNOSIS
Clinical history:
- Clear watery discharge from the nose when bending the head forward or straining (stools/micturition)
- Reservoir sign: On rising in the morning, the patient bends his head and a stream of fluid gushes out - this is fluid that had collected overnight in the sinuses (especially sphenoid), which then empties into the nose
Key distinguishing features from rhinitis discharge:
- CSF discharge is sudden, gushes in drops on bending, and cannot be sniffed back
- Nasal mucus is continuous, unaffected by bending, and can be sniffed back
- CSF does NOT stiffen the handkerchief (no mucus); nasal discharge does
Double target sign:
- When CSF rhinorrhoea occurs after head trauma, fluid mixed with blood is collected on filter paper
- Shows a central red spot (blood) surrounded by a peripheral lighter halo (CSF)
Endoscopy: Nasal endoscopy can help localize the leak site. Otoscopy/microscopy may reveal fluid in the middle ear in otorhinorrhoea cases.
6. DIFFERENCES BETWEEN CSF AND NASAL SECRETIONS (Table 29.1)
| Feature | CSF Fluid | Nasal Secretion |
|---|---|---|
| History | Nasal/sinus surgery, head injury, intracranial tumour | Sneezing, nasal stuffiness, itching, lacrimation |
| Flow of discharge | Few drops or stream; gushes on bending/straining; cannot be sniffed back | Continuous; no effect of bending or straining; can be sniffed back |
| Character | Thin, watery and clear | Slimy (mucus) or clear (tears) |
| Taste | Sweet | Salty |
| Sugar content | >30 mg/dL | <10 mg/dL |
| β₂ transferrin | Always present (specific for CSF) | Always absent |
7. LABORATORY TESTS
Beta-2 Transferrin (Gold Standard)
- A protein found only in CSF (and not in nasal discharge)
- Highly specific and sensitive
- Requires only a few drops of specimen
- Also found in perilymph and aqueous humour (the only other fluids containing this protein)
Beta Trace Protein
- Also specific for CSF
- Widely used in Europe
- Secreted by meninges and choroid plexus
- Not universally available
Note: Glucose testing (by oxidase-peroxidase or biochemical estimation) is no longer used due to low specificity.
8. LOCALIZATION OF THE SITE
| Method | Details |
|---|---|
| 1. High-resolution CT scan | 1-2 mm cuts; coronal AND axial cuts to detect bony defects; axial cuts for frontal or sphenoid defects |
| 2. MRI (T2-weighted) | Shows active CSF leak; noninvasive; indicated if encephalocoele or intracranial pathology suspected; leak must be active at time of scan |
| 3. CT cisternogram | Intrathecal injection of iohexol + CT scan; used when β₂ transferrin unavailable; not favoured now |
| 4. Intrathecal fluorescein | Invasive; 0.25-0.5 mL of 5% fluorescein diluted in 10 mL CSF injected intrathecally; patient lies in 10° head-down position; dye appears bright yellow normally, fluorescent green with blue filter; done pre-op or intraoperatively |
The endoscopist should examine:
- Olfactory cleft (cribriform plate)
- Middle meatus (frontal and ethmoid sinuses)
- Sphenoethmoidal recess (sphenoid sinus)
- Area of torus tubarius (temporal bone fracture)
(Use of intrathecal radioactive substances has been abandoned)
9. TREATMENT
Conservative Management
(For early post-traumatic cases)
- Bed rest
- Elevate head of bed
- Stool softeners (to avoid straining)
- Avoid nose blowing, sneezing, straining
- Prophylactic antibiotics (to prevent meningitis)
- Acetazolamide - decreases CSF formation
- Lumbar drain - if indicated, combined with above measures
Surgical Repair
1. Neurosurgical intracranial approach
2. Extradural approaches (now rarely used):
- External ethmoidectomy - for cribriform plate and ethmoid
- Transseptal sphenoidal approach - for sphenoid
- Osteoplastic flap - for frontal sinus leak
3. Transnasal endoscopic approach (Treatment of choice)
- Success rate of 90% on first attempt
- Manages most leaks from anterior cranial fossa and sphenoid sinus
10. PRINCIPLES OF ENDOSCOPIC REPAIR
Step-by-step:
(a) Define the bony defect site (Fig. 29.5) - can be:
- Cribriform plate
- Lateral lamina close to anterior ethmoid artery
- Roof of ethmoid
- Frontal sinus
- Sphenoid sinus
(b) Prepare the site for graft placement
(c) Underlay grafting:
- Fascia placed extradurally (fascia lata obtained from thigh)
- Followed by placement of mucosa (free graft or pedicled flap) - see Fig. 29.6
(d) Large defects (>2 cm):
- Repaired with cartilage (from nasal septum or auricular concha)
- Followed by mucosa placement
(e) Additional support:
- Surgicel and Gelfoam placement
- High antibiotic smeared nasal pack
- Fat from thigh or abdomen can be used instead of fascia for plugging
(f) Lumbar drain - if CSF pressure is high
(g) Antibiotics
Special case: CSF leak from frontal sinus often requires osteoplastic flap operation and obliteration of the sinus with fat
Layered Repair - Fig. 29.6 (from superficial to deep):
| Layer | Material |
|---|---|
| 1. Nasal pack | Bottom support |
| 2. Gelfoam | Below mucosa |
| 3. Surgicel | Above Gelfoam |
| 4. Mucosa | Covers graft |
| 5. Skull base | Bony boundary |
| 6. Fascial graft | Extradural (underlay) |
| 7. Dura | Uppermost layer |
This complete coverage of CSF rhinorrhoea as per Dhingra ENT encompasses the definition, physiology, all causes, clinical presentation with key signs (reservoir sign, double target sign), lab diagnosis, imaging, and both conservative and surgical management including the modern endoscopic technique with its high success rate.
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