Case of Left thalamic cryptogenic abscess

Dr.Ghaniya KC, Dr.C Jayakumar 

Four year old female child ,presented with complaints of intermittent high-grade fever since two weeks, headache for 10 days, and vomiting for 4 days, with one episode of seizure characterized uprolling of eye ball and stiffening of all four limbs 

No significant perinatal /past history of any illness

CLINICAL EXAMINATION :
Child active, alert, playful
GCS E4V5M6
BIlateral pupils are reactive to light.
Moving all 4 limbs.
Systemic Examination:
CVS S1S2 heard , no murmurs
RESP Normal sure enter +, no added sounds.
P/a soft, non tender.

Laboratory Findings:

•CBC, CRP – within normal limits 
• Blood culture – sterilise to the persistence of symptoms MRI was done outside hospital and that showed?Thalamic abscess 

Diagnostic Imaging: MDCT Neuronavigation Study 
• Left thalamic lesion measuring 26 x 36 x 30 mm (AP x TR x CC).
• Notable mass effect with effacement of sulcal spaces and right lateral ventricle.
• Midline shift of 3 mm to the right.
Child underwent craniotomy 

Child underwent ROSA-guided aspiration of the left thalamic abscess under general anesthesia.

•Fungal: No growth after 48 hours and 7 days.
• Pus/Wound Swab/Aspirate: 
No growth after 48 hours and 7 days.
• GeneXpert MTB-RIF: Mycobacterium tuberculosis complex not detected.
• Smear Gram: Very few inflammatory cells, few Gram-positive cocci in chains.
• Smear for AFB: Negative (both direct and concentration).

Clinical Course:
Following the procedure, the child was transferred to the ICU for neurological and hemodynamic monitoring before being moved to the ward. Post-operative CT brain confirmed no fresh bleeding.

Pediatric cardiology and ENT evaluations were performed to rule out infective endocarditis and other ENT causes. Dental examination ruled out oral caries as a possible source of infection.

The child was treated with:

• Inj. Ceftriaxone (17 days)
• Inj. Metronidazole (15 days)
• Inj. Vancomycin (8 days)

Wound dressing was performed, and the wound remained healthy throughout the hospital stay.

Thalamic Abscesses:
• Deep-seated metastatic lesions of hematogenous origin.
• Possible causes include:
• Congenital heart disease with right-to-left shunts.
• Intrathoracic or abdominal sepsis.
• Local origins like dental caries, otitis media, or sinusitis.
• May be cryptogenic.

Common organisms:
• Streptococci, particularly Streptococcus anginosus group.
• Anaerobes.

S. anginosus promotes abscess formation through:
• Toxins with leukocidin-like and thrombin-like activity.
• Resistance to phagocytosis.

Mechanisms of Infection S. anginosus:
• Contiguous spread from near infection sites (e.g., sinusitis, otitis media).
• Hematogenous spread from distant sites (e.g., gastrointestinal, respiratory tract).

Risk Factors for Thalamic Abscesses due to S. anginosus:
• Liver cirrhosis, malignancy, diabetes mellitus, malnourishment, immunosuppression.
• Periodontal disease is an independent risk factor for brain abscesses.

Clinical Presentation:
• Common symptoms include fever, leukocytosis, headache, altered sensorium, and hemiparesis.

Management of Thalamic Abscesses:
Aspiration methods:
• Burr hole, stereo-endoscopic aspiration, ultrasound-guided aspiration.
• Stereotactic aspiration is preferred neurosurgeons for its diagnostic and therapeutic benefits.
• Medical therapy reserved for:
• Multiple or small abscesses.
• Patients at high risk for surgery.
• Antimicrobial therapy typically lasts 4–8 weeks.

Eradication of Primary Focus:
• Essential for a favorable outcome.
• In cases without identifiable primary focus, risks increase for abscess formation and systemic morbidity.
• Mortality rate for thalamic abscess is 9–14%, with increased risk if intraventricular rupture occurs.

Diagnostic Approaches:
• Computer tomography (CT) with contrast is the primary diagnostic tool.

Differential diagnosis includes:
• Fungal, nocardial, or tubercular abscesses, neurocysticercosis, toxoplasmosis, glioblastoma, metastasis, etc.