CSOM Clinical Overview
I. The "On-Call" Snapshot
Clinical Significance in Malaysia: This is a bread-and-butter ENT problem in our clinics and a major cause of preventable hearing loss, especially in rural communities. You will see this frequently.
High-Yield Definition: CSOM is a chronic inflammation of the middle ear and mastoid cavity, characterized by a persistent or recurrent purulent discharge through a non-intact tympanic membrane (perforation) for more than 6 weeks. (Sourced from UpToDate and general consensus).
Clinical One-Liner: Basically, it's a persistently leaking ear through a hole in the eardrum because of chronic infection.
II. Etiology & Risk Factors
Etiology: It's a progression from an unresolved episode of Acute Otitis Media (AOM) with tympanic membrane perforation. The infection becomes persistent and polymicrobial. Common culprits in our setting are Pseudomonas aeruginosa and Staphylococcus aureus. Fungi like Aspergillus can also be involved, especially with inappropriate antibiotic use.
Risk Factors (Local Context):
Non-Modifiable:
Craniofacial anomalies (e.g., Cleft palate, Down syndrome).
Eustachian tube dysfunction.
Modifiable:
Recurrent upper respiratory tract infections.
Poor socioeconomic conditions: crowded living, poor hygiene.
Passive smoking.
Malnutrition.
Previous ventilation tube (grommet) insertion.
III. Quick Pathophysiology
Forget the deep molecular details. Just understand this: A perforation allows bacteria from the external canal and nasopharynx to enter the normally sterile middle ear. The Eustachian tube isn't working properly to clear it. This leads to a vicious cycle of inflammation, mucosal edema, ulceration, and granulation tissue formation. This cycle prevents the perforation from healing and perpetuates the discharge. In unsafe CSOM, this process is complicated by cholesteatoma formation.
IV. Clinical Assessment
Red Flags & Immediate Actions (Escalate to MO/Registrar):
Fever, severe otalgia, headache: Suspect intracranial complication -> Alert senior, prepare for imaging (CT).
Vertigo or nystagmus: Suggests labyrinthine involvement -> Alert senior, keep patient nil by mouth (NBM).
Facial nerve palsy (facial drooping): Indicates nerve erosion -> Urgent ENT consult.
Post-auricular swelling, erythema, or tenderness: Suggests mastoiditis -> Urgent ENT consult.
History:
Common (>50%):
Painless, persistent, or intermittent purulent ear discharge (otorrhoea). It might be foul-smelling, which is suggestive of anaerobic infection or cholesteatoma.
Hearing loss in the affected ear (conductive type).
Less Common (10-50%):
Aural fullness, tinnitus.
Pertinent Negatives:
Ask about pain. The absence of pain is characteristic of uncomplicated CSOM. The presence of pain is a red flag.
Ask about vertigo, facial weakness, and headache to rule out complications.
Physical Examination:
Otoscopy is key. You must be able to identify the landmarks.
Canal: May contain pus, debris, granulation tissue, or a polyp.
Tympanic Membrane (TM): Note the perforation.
Location: Central vs. Marginal/Attic. This is the most critical distinction.
Central: Perforation is surrounded by a remnant of the TM. Usually considered "safe" (tubotympanic) disease.
Marginal/Attic: Perforation involves the edge (annulus) or the pars flaccida (attic). Highly suspicious for "unsafe" (atticoantral) disease with cholesteatoma.
Discharge: Note the character (mucoid, purulent, blood-stained).
Middle Ear Mucosa: May be visible through the perforation; can be oedematous, granular, or pale.
Tuning Fork Tests (512 Hz):
Rinne's Test: Negative on the affected side (Bone Conduction > Air Conduction).
Weber's Test: Lateralizes to the affected ear.
Clinical Pearl: If you see granulation tissue or a polyp coming through the perforation, you must suspect a cholesteatoma until proven otherwise. Do not try to remove it in the clinic.
V. Diagnostic Workflow
Differential Diagnosis:
Otitis Externa:
Points For: Ear discharge.
Points Against: Significant pain, especially on tragal pressure or pinna manipulation. TM is usually intact.
How to Differentiate: Otoscopy showing an inflamed external canal with an intact TM.
Foreign Body in Ear:
Points For: Unilateral ear discharge.
Points Against: History of insertion (though may be absent in children).
How to Differentiate: Direct visualization with otoscopy.
Tuberculous Otitis Media:
Points For: Chronic, painless discharge unresponsive to standard antibiotics. Multiple TM perforations.
Points Against: Usually associated with systemic signs of TB.
How to Differentiate: Ear swab for AFB stain and TB culture. Chest X-ray.
Investigations Plan:
Bedside / Initial:
Aural toilet: Gentle dry mopping or microsuction to clear discharge and visualize the TM properly. This is both diagnostic and therapeutic.
First-Line Labs & Imaging:
Ear Swab for Culture & Sensitivity (C&S): Essential to guide antibiotic therapy, especially in treatment failure. Swab from the middle ear through the perforation if possible.
Pure Tone Audiogram (PTA): To quantify the degree of hearing loss and establish a baseline before any surgical intervention.
Confirmatory / Pre-operative:
High-Resolution Computed Tomography (HRCT) of Temporal Bones: This is not for every case. It is the gold standard to assess for cholesteatoma, ossicular chain erosion, and bony anatomy prior to surgery. Indicated if you suspect unsafe disease or complications.
VI. Staging & Severity Assessment
In CSOM, we don't use a numerical staging system. The classification is clinical and has direct management implications.
Tubotympanic CSOM ("Safe" Type):
Features: Central perforation, mucoid discharge (intermittent), no cholesteatoma. The disease is confined to the mucosa of the middle ear cleft.
Impact: Primarily managed medically. Surgery (myringoplasty) is for hearing improvement and to achieve a dry ear.
Atticoantral CSOM ("Unsafe" Type):
Features: Attic or marginal perforation, often with foul-smelling scanty discharge. Associated with cholesteatoma.
Impact: This is a surgical disease. The cholesteatoma is locally destructive and can lead to serious complications. Medical treatment is only a temporizing measure.
VII. Management Plan
A key point to note: There is no specific, dedicated Malaysian CPG for CSOM. Our management is guided by international guidelines (like those from UpToDate) and established ENT principles, adapted to our local microbiology.
Immediate Stabilisation (Rarely needed unless complicated):
Follow the ABCDE approach if the patient is systemically unwell or showing signs of intracranial complications.
Definitive Treatment (The Ward/Clinic Plan):
Aural Toilet: This is the most crucial first step. You cannot treat what you cannot see. Regular and thorough cleaning of the ear canal from discharge and debris is mandatory. This can be done via gentle dry mopping or microsuction.
Topical Antibiotics (First-Line):
Quinolone-based drops (e.g., Ciprofloxacin, Ofloxacin) are first-line because they are effective against Pseudomonas and are non-ototoxic.
Dose: 3-4 drops, two to three times a day for at least 2 weeks. The ear should be clean before instillation.
Often combined with a steroid (e.g., Dexamethasone) to reduce inflammation and oedema.
Systemic Antibiotics:
Generally reserved for acute exacerbations or when there are signs of spreading infection.
Choice should be guided by C&S results. Empirical treatment can be started with an anti-pseudomonal agent if needed.
Control of Granulation Tissue:
May be cauterized by the MO or specialist using silver nitrate.
Surgical Intervention:
Myringoplasty: To close a perforation in "safe" CSOM once the ear has been dry for at least 3 months.
Tympanoplasty: Repairing the TM and reconstructing the ossicular chain.
Mastoidectomy: The treatment for "unsafe" CSOM (cholesteatoma). The primary goal is to eradicate the disease and create a safe, dry ear. Hearing restoration is a secondary goal.
Long-Term & Discharge Plan:
Dry Ear Precautions: Crucial for all patients with a perforation. Advise them to prevent water from entering the ear during bathing or swimming (use cotton balls with vaseline).
Follow-up: Regular follow-up in the ENT clinic to monitor for recurrence and hearing status.
Education: Explain the type of CSOM (safe vs. unsafe) and the importance of compliance and follow-up.
VIII. Complications
You must know these. They are divided into intratemporal (within the temporal bone) and intracranial (inside the skull).
Intratemporal:
Hearing Loss (Conductive/Mixed): Management: Surgical reconstruction (tympanoplasty).
Mastoiditis: Management: IV antibiotics, may require mastoidectomy.
Facial Nerve Palsy: Management: High-dose steroids, urgent surgical decompression may be needed.
Labyrinthitis: Management: Bed rest, vestibular sedatives, IV antibiotics.
Intracranial (Life-threatening):
Meningitis: Management: IV antibiotics, neurosurgical consult.
Brain Abscess (Temporal lobe or Cerebellar): Management: IV antibiotics, urgent neurosurgical drainage.
Lateral Sinus Thrombophlebitis: Management: IV antibiotics, anticoagulation, surgical drainage.
IX. Prognosis
With appropriate medical and surgical treatment, the prognosis for a dry, infection-free ear is good.
Hearing improvement depends on the state of the ossicular chain.
Prognostic Factors:
Presence of Cholesteatoma: "Unsafe" disease has a higher risk of complications and recurrence.
Eustachian Tube Function: Poor function increases the risk of treatment failure.
Patient Compliance: Adherence to dry ear precautions and follow-up is critical.
X. How to Present to Your Senior
"Dr, for your review, please. This is [Patient's Name] in [Bed/Clinic Room], a [Age]-year-old [Gender], who presented with persistent right ear discharge for the past [Duration].
On examination, there is a [central/marginal] perforation in the right tympanic membrane with purulent discharge. Rinne's test is negative on the right. There are no red flag symptoms like fever or facial weakness.
My main differential is Chronic Suppurative Otitis Media, likely the [tubotympanic/atticoantral] type. I have taken an ear swab for C&S and have scheduled the patient for an audiogram. I would like to ask about starting topical Ciprofloxacin drops after aural toileting."
XI. Summary & Further Reading
Top 3 Takeaways:
The most important step is to clean the ear and determine if the perforation is central (safe) or marginal/attic (unsafe).
Management always starts with meticulous aural toilet followed by topical quinolone antibiotic drops.
Pain, fever, vertigo, or facial palsy are red flags for serious complications and require immediate escalation.
Key Resources:
UpToDate: Search for "Chronic suppurative otitis media (CSOM): Treatment, complications, and prevention". This is your best evidence-based summary.
StatPearls: Search for "Chronic Suppurative Otitis". Good for a quick, high-yield overview.
Malaysian Data: While there isn't a national CPG, local microbiology studies often show Pseudomonas aeruginosa and S. aureus as primary pathogens, justifying the empirical use of quinolones. (e.g., search PubMed for "bacteriology CSOM Malaysia").
