Post by @FTeranmd

55 yo F with PMHx of asthma who presented to the ED complaining of headache, low grade fever and word-finding difficulty. On further interrogation, patient endorsed having eaten Brie cheese recently. Her medications included albuterol and inhaled fluticasone.

In the ED patient was uncomfortable-appearing, with VS: T 101, HR 105, BP 130/70, RR 16 Sat O2 97% RA.

Physical exam was remarkable for low-grade fever, expressive aphasia and no meningeal signs.

ED team was concerned for possible CNS infection. CT non contrast was done given focal symptoms but no abnormalities were identified.

Blood work was remarkable for leukocytosis with bandemia. Patient was given empiric antibiotics and LP was performed.

Would you perform any additional imaging on this patient?

What specific infection would you suspect?

CSF results: 250 WBC /ml  30% lymphocytes, Protein 6 g/l glucose 30 gr/dl  with Gram-positive rods

Contrast enhanced MRI was performed, showing diffuse high signal throughout the sulci of both cerebral hemispheres, particularly in the parietal and occipital lobes on T2 flair series.

Contrast-enhanced brain MRI. T2 flair
Contrast-enhanced brain MRI. T2 flair

On day 2 CSF cultures resulted positive for listeria. Clinical picture was thought to be listeria meningoencephalitis with focal neurological deficits (expressive aphasia). Patient was treated with Ampicillin and recovered successfully. Risk factors that prompted suspicion of listeriosis in this patient were the clinical presentation and Hx of Brie cheese consumption, and possibly immunosuppressive effect from chronic inhaled corticosteroids.

Listeria monocytogenes, a motile, short gram-positive rod is an important infection in neonates, immunosuppressed patients, pregnant women and older adults, and occasionally previously healthy individuals. The infection causes a wide spectrum of invasive disease including gastroenteritis, bacteremia and several types of CNS infections, including meningitis, meningoencephalitis, cerebritis, rhomboencephalitis and focal infections.

Diagnosis is made by blood cultures of CSF cultures. Gram stain of CSF has a low sensitivity, positive only in one third of patients.  Contrast-enhanced MRI is recommended for all patients with listeria in CSF and those with high suspicion despite negative cultures due to the relatively high frequency of brain abscesses in the setting of low sensitivity of cultures.

Classic clinical pictures:

–       Febrile gastroenteritis

–       Neonatal infection

–       Infection in pregnancy

–       CNS infection:

  • Minigoencephalitis
  • Cerebritis
  • Rhomboencephalitis

–       Focal infections

  • Ocular (Perinaud syndrome)
  • Empyema, myocarditis, septic arthritis, osteomyelitis
  • Spinal and brain abscess
  • Cholecystitis
  • Peritonitis (patients with peritoneal dialysis)

As shown in this case, listeria has been reported to cause focal neurological symptom in up to one third of patients with CNS infection. Focal deficits include aphasia, hemiparesis, cranial nerve palsy and ataxia.

Therapy: first line therapy is Ampicillin or penicillin G, and alternative therapies include Trimethoprim-sulfamethoxazole and meropenem

Empiric coverage for listeria meningitis should be given to patients < 1 month and > 50 years

Food epidemiology and sources: sources of listeria infection include soft cheeses such as feta, Brie and Camembert, blue-veined cheese and Mexican style cheeses such as queso blanco, queso fresco and panela.

Initial management of acute bacterial meningitis in adults: summary of IDSA guidelines. Beckham JD, Tyler KL; IDSA. Rev Neurol Dis. 2006 Spring;3(2):57-60.


May 2024