วันเสาร์ที่ 14 กรกฎาคม พ.ศ. 2555

CNS infection

Bacterial meningitis

Clinical: fever, neck stiffness, altered mental status

PE: sign of meningeal irritation (Brudzinski sign, Kernig sign)

Skin: purpura (meningococcemia, streptococcemia, rickettsial infection), microembolization (petechiae, splinter hemorrhages, pustular lesions)

HEENT for evidence of primary infection

Sign of IICP, focal neurologic deficit: EOM, VF, facial asymmetry, hemiparesis, papilledema, loss of venous pulsation

Treatment

ATB: ceftriaxone 2 gm IV q 12 h + vancomycin 15 mg/kg IV q 8-12 h +/- ampicillin 2 gm IV q 4 h if > 50 y

     o Penicillin allergy: vancomycin 15 mg/kg IV q 8-12 h + moxifloxacin 400 mg IV OD + bactrim 10-20 mg/kg/d IV q 6-12 h

     o Penetrating inj, neurosx, CSF shunt: vancomycin 25 mg/kg IV load + ceftazidime 2 gm IV q 8 h or meropenam

     o Complicated sinusitis/otitis: ceftriaxone 2 gm IV q 12 h + metronidazole; consult ENT

• Dexamethasone 0.15 mg/kg or 10 mg IV before ATB if strong suspicion for bacterial meningitis

• Chemoprophylaxis for N. meningitides if direct contact to secretion in previous 7 d: rifampicin 10 mg/kg (max 600 mg) PO q 12 h x 4 doses or ciprofloxacin

Investigaition

CT brain: estimate benefit-risk (altered mental status, focal neurologic deficit, seizure, papilledema, immunocompromised, malignancy, Hx of focal CNS disease (stroke, focal infection, tumor), > 60 y)

CSF: OP, cell count, differentiated, protein, glucose, G/S, C/S, latex agglutination, board-base PCR, lactate, CRP, +/- Indian ink, AFP, viral C/S

• Serum glucose, cryptococcal Ag, H/C
















Viral meningitis

Tx as bacterial meningitis until culture result

          o Ddx partially tx, early bacterial meningitis, 10% of L. monocytogenes and neonatal meningitis

• Known or suspected HSV-2 meningitis(neurologic deficits, such as urinary retention or weakness): tx with acyclovir 10 mg/kg IV q 8 h

Viral encephalitis

Clinical: new psychiatric symptoms, cognitive deficits (e.g. aphasia, amnestic syndrome, acute confusional state), seizures, movement disorders; +/- headache, photophobia, fever

HSV (limbic structures of the temporal and frontal lobes): prominent psychiatric features, memory disturbance, aphasia

HZV: shingles, chickenpox, immunosuppressed state

EBV: mononucleosis

CMV: lymphadenopathy, hepatosplenomegaly

Arboviruses (basal ganglia): choreoathetosis, parkinsonian movements; seasonal

Rabies (brainstem nuclei that control swallowing): hydrophobic choking ; animal bite

Japanese encephalitis: แม่ฮ่องสอน มุกดาหาร กำแพงเพชร สมุทรสาคร น่าน; (severe 1:200) high fever, neck stiffness, disorientation, seizure, coma, spastic paralysis

w/u: MRI (CT), EEG, LP (show finding of viral meningitis)

DDx other cause encephalitis (see alteration of consciousness)

Treatment

• Supportive tx

HSV/HZV encephalitis: acyclovir 10 mg/kg q 8 h; CMV encephalitis: ganciclovir 5 mg/kg IV q 12 h

Brain abscess

Clinical: nonspecific; classic triad of headache, fever, focal neurologic deficit (hemiparesis, seizure); neck stiffness, vomiting, confusion; meningeal signs/papilledema/focal deficit (frontal lobes, hemiparesis; temporal lobes, homonymous superior quadrant VF deficit or aphasia; cerebellum, limb incoordination/nystagmus)

Find potential source: otitis media, sinus tenderness, evidence of pulmonary suppuration, right-to-left shunting

w/u: CT with contrast (thin, smoothly contoured rings of enhancement surrounding a low-density center and surrounded by white matter edema), H/C, brain biopsy/aspirate

DDx: brain neoplasm, subacute brain hemorrhage, toxoplasmosis

Treatment

• Consult neurosurgeon, infectious

ATB in HEENT/hematogenic or no obvious source: cefotaxime 2 gms IV q 6 h + metronidazole 500 mg IV q 6 h

Penetrating trauma or neurosurgical sx: vancomycin 15 mg/kg IV q 12 h (max 1 gm) + ceftazidime 2 gm IV q 8 h

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