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Flashcards in Infectious Deck (40)
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1
Q

What CD4 count predisposes to toxoplasmosis brain lesions?

A

<100

2
Q

Where is toxoplasmosis typically found in the brain?

A

The basal ganglia/thalamic region

3
Q

What are Argyll Robertson pupils?

A

They are bilateral small pupils that reduce in size on a near object (i.e., they accommodate), but do not constrict when exposed to bright light (i.e., they do not react to light) - “light-near dissociation”. They are a highly specific sign of neurosyphilis

4
Q

What bacterial disease can present with absence of DTRs and a positive Romberg sign?

A

Neurosyphilis

5
Q

What is the most common etiology of cavernous sinus thrombosis?

A

Uncontrolled infection of the central facial skin, the orbit, or nasal sinuses that leads to septic thrombosis. Staph aureus is the most common causative agent

6
Q

What is postinfectious cerebellitis?

A

Typically affects children between ages of 2 and 7 and usually follows a varicella or other viral infection. Children present with acute onset of limb and gait ataxia as well as dysarthria. Dx of exclusion

7
Q

What is Miller Fisher syndrome?

A

Thought to be a variant of Guillain-Barré syndrome that leads to a triad of ataxia, areflexia, and ophthalmoplegia. The ataxia is due to loss of proprioception rather than cerebellar causes. Thought to be postinfectious and most patients recover fully

8
Q

What is PANDAS?

A

Pediatric autoimmune neurologic disorders associated with streptococcal infection. The child develops exacerbation of tics, OCD or both following a group A beta-hemolytic strep infection

9
Q

What is progressive multifocal leukoencphalopathy (PML) and what causes it?

A

Caused by the JC virus and leads to demyelination by infecting oligodendrocytes. Leads to dementia, focal cortical dysfunction, and cerebellar abnormalities. Mortality is ~50%

10
Q

How does tuberculosis meningitis differ from acute pyogenic bacterial meningitis?

A

It has a predilection for affecting the basal meninges leading to cranial nerve palsies and more commonly causes hydrocephalus and brain infarcts. It also has a more subacute presentation with a prolonged prodrome of malaise and nonspecific constitutional symptoms. The CSF profile demonstrates a leukocytosis with lymphocytic predominance (as opposed to PMNs) and CSF glucose is often very low.

11
Q

What are the neurologic complications associated with Lyme disease?

A

Aseptic meningitis and/or facial nerve palsy within weeks after infection. Later manifestations include leukoencphalopathy and painful polyradiculopathy

12
Q

What are symptoms of HSV1 encephalitis?

A

Tends to infect the medial temporal lobes and orbitofrontal regions of the cortex leading to limbic dysfunction (e.g. complex partial seizures of mesial temoral lobe origin, olfactory hallucinations and memory disturbances including sometimes profound anterograde amnesia). The CSF profile often demonstrates and elevated RBC count and leukocytosis. Treated with prolonged IV course of acyclovir

13
Q

What is the CSF profile of fungal meningitis?

A

Lymphocytic predominance, elevated protein and low glucose

14
Q

What is vaculoar myelopathy?

A

A late complication of severe immunosuppression cause by HIV. It resembles B12 deficiency with loss of vibration and joint position sense (dorsal column), with sensory ataxia along with corticospinal tract dysfunction (spasticity and hyperreflexia) bilaterally. May also cause urinary and sexual dysfunction.

15
Q

What are the autoantibodies in Guillain-Barré syndrome (GBS) directed against?

A

Gangliosides (e.g. anti-GM1 is most common, may also see anti-GD1a, antiGQ1b, etc)

16
Q

How does Guillain-Barré syndrome present?

A

Areflexic motor paralysis with or without sensory disturbances, including neuropathic pain

17
Q

What is the Miller-Fisher varian of GBS?

A

Characterized by gait ataxia, areflexia, and external ophthalmoplegia usually without limb weakness. Anti-GQ1b antibodies are often present

18
Q

What diagnostic tests are done for GBS?

A

LP shows elevated protein but few or no cells in the CSF. EMG may show prolonged distal latencies, variably prolonged or absent F waves, possible conduction block and decreased motor unit recruitment

19
Q

What is treatment for GBS?

A

May require intubation. Can give IVIg or do plasmapheresis. Note that IV steroids are not effective

20
Q

Below what forced vital capacity (FVC) should a patient with GBS be intubated?

A

<15 mL/kg of body weight

21
Q

What are characteristics of the neuropathy of leprosy?

A

Caused by M. leprae and characterized by sensory and motor involvement. It presents with mononeuropathy multiplex or mononeuropathies with a predilection for cooler areas of the body. Deep tendon reflexes are usually preserved. There is often nerve hypertrophy which can be palpated

22
Q

What is pandyautonomia?

A

An acquired disorder, usually immune in nature, often following a viral infection. Involves both sympathetic and parasympathetic NS (antibodies are formed against the autonomic NS - ganglionic ACh receptor antibodies) - symptoms may include orthostatic hypotension, anhidrosis, unreactive pupils, decreased lacrimation and salivation, gastrointestinal paresis, and impaired genitourinary function.

23
Q

What is the CSF profile in Guillain-Barré?

A

Albuminocytologic dissociation (high protein with almost no cells)

24
Q

What infection is the most common cause of polyradiculitis or cauda equina syndrome in an immunocompromised individual?

A

CMV

25
Q

What was a striking neurologic complication of von Economo encephalitis (associated with the Spanish flu)?

A

Parkinsonism

26
Q

How can Schistosoma mansoni damage the nervous system?

A

It can produce a subacutely evolving paraparesis by depositing its eggs into veins from the intestines that communicate with drainage from the lumbosacral spine. The patient develops granulomas around the ova that lodge in the spinal cord, and these lesions crush the cord

27
Q

What parasite can form hydatid cysts (a large cyst surrounded by smaller cysts) in the brain?

A

Echinococcosis from dog or sheep fecal matter

28
Q

What is the CSF profile of Creutzfeldt-Jakob disease?

A

Often normal. Can have a 14-3-3 proteinase inhibitor profile

29
Q

What should be done in an AIDS patient seen to have a ring-enhancing brain lesion on contrast CT?

A

Perform an LP and include PCR for EBV. The lesion is most likely lymphoma or Toxoplasmosis. The CSF EBV PCR test is highly specific and sensitive for primary CNS lymphoma

30
Q

What CNS infections characteristically cause microglial nodules?

A

HIV and CMV

31
Q

Where in the brain do infectious abscesses usually occur?

A

At the gray-white junction

32
Q

What fungus is the most common cause of fungal abscesses?

A

Aspergillus

33
Q

What is the most common symptom of a brain abscess?

A

Headache

34
Q

What is the most common causative infectious agent of brain abscesses?

A

Anaerobic and aerobic streptococcus species make up over half of brain abscesses

35
Q

What CNS infection has inclusion bodies in oligodendrocytes?

A

JC virus

36
Q

What are features of subacute sclerosing panencephalitis (SSPE)?

A

Usually occurs children with a history of measles infection (may appear 6-8 years later). The CSF pattern is similar to MS with and increase in the g-globulin fraction and the presence of oligoclonal bands. It causes a demyelinating disease that leads to death in 1-3 years. Eosinophilic inclusions are seen in the cytoplasm and nuclei of neurons and glial cells.

37
Q

What organism causes increased signal intensity on MRI in the pulvinar (posterior thalamus)?

A

Bartonella henselae

38
Q

What is oculomasticatory myorhythmia (pendular convergence movements of the eyes in association with contraction of the muscles of mastication) pathognomonic for?

A

T whippeli infection of the CNS

39
Q

What is Gradenigo syndrome?

A

Caused by osteomyelitis of the petrous pyramid (may be due to chronic ear infections). This can damage the abducens and trigeminal nerves as they pass close to the tip of the petrous bone - causes a 6th nerve palsy and facial pain

40
Q

What ocular motor nerve can be damaged in ocular varicella zoster infections?

A

CN IV because it shares a nerve sheath with the ophthalmic division of the trigeminal nerve