Differentials
Other bacterial meningitides
SIGNS / SYMPTOMS
There is no sign or symptom that securely differentiates listeriosis from other causes of central nervous system (CNS) infection.
Nuchal rigidity is more common in meningitis due to pathogens other than Listeria.[1][6]
INVESTIGATIONS
Cerebrospinal fluid (CSF) Gram stain, CSF culture, and blood culture are the tests of choice.
Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae are common causes of community-acquired bacterial meningitis. Meningitis/encephalitis panel tests cerebrospinal fluid for common bacterial pathogens responsible for meningitis or encephalitis.
Other brain abscesses
SIGNS / SYMPTOMS
There is no sign or symptom that securely differentiates listeriosis from other causes of CNS infection.
INVESTIGATIONS
Culture and Gram stain will typically differentiate other organisms. Additionally, blood cultures are frequently positive in listeriosis.
Viral gastroenteritis
SIGNS / SYMPTOMS
Viral gastroenteritis may be accompanied by upper respiratory symptoms.
A history of consumption of foods suspicious for listeriosis may be absent.
INVESTIGATIONS
Stool tests are negative for Listeria.
Other bacterial gastroenteritides
SIGNS / SYMPTOMS
Social history, food-consumption history, travel history, incubation period, history of alimentary tract contamination, presence of dysentery, and sporadic or epidemic cases are used to differentiate the causes clinically. Presenting signs and symptoms may be similar to listeriosis. In Shigella infection, stool may contain blood or pus.
INVESTIGATIONS
Stool tests or serologies may be positive for organisms such as Campylobacter jejuni, Salmonella, or Shigella.
Toxoplasmosis
SIGNS / SYMPTOMS
History of consumption of raw meat or having a house cat.
Unexplained fever and generalized lymphadenitis.
INVESTIGATIONS
Serology for IgM and IgG antibodies against Toxoplasma gondii may be present.
Microscopy of an infected lymph node may confirm toxoplasmosis.
Sarcoidosis
SIGNS / SYMPTOMS
May affect any organ, but erythema nodosum is a more specific presentation for sarcoidosis.
INVESTIGATIONS
Chest radiography may show bilateral enlargement of hilar lymph nodes.
Biopsy of lymph node or affected tissue may show granulomas without central necrosis.
Hypercalciuria may be present.
Vasculitis
SIGNS / SYMPTOMS
Systemic symptoms or signs may be similar, rendering diagnosis difficult.
INVESTIGATIONS
Biopsy of affected organ may show thrombosis and inflammation of any size of vasculature and invasion of vessel wall by inflammatory cells.
Septic abortion
SIGNS / SYMPTOMS
There are no distinguishing features compared with other causes.
Fever and rigors in pregnant women and bacteremia due to any site of infection may cause chorioamnionitis, fetal sepsis, and death.
INVESTIGATIONS
Blood, placenta, amniotic fluid cultures will determine the underlying etiologic organism.
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