2025 – PAGE 398 – NEUROLOGY

EPIDURAL ABSCESS OF THE SPINE

An epidural abscess of the spine presents with a history of fever, pain, lower extremity weakness, numbness and tingling (paresthesias), and eventually paralysis. Exam will show increased reflexes. Get a STAT MRI of the spine to look for the abscess with compression of the spinal cord. Start anti-staphylococcal antibiotics and call a neurosurgeon. You should also give dexamethasone for this or any other spinal cord compression syndrome.

PEARL: Some of the symptoms may seem similar to Guillain Barre Syndrome (GBS), but key differences include a lack of sensation, poor rectal tone, and a lack of bowel and bladder control in epidural abscesses (and any other cord compression syndrome). In GBS, continence is preserved.

MYASTHENIA GRAVIS (MG)

Myasthenia gravis (MG) findings will include either a baby with variable ptosis (not constant, occurring at different times), or an older child with evidence of muscle weakness that waxes and wanes. On exam, reflexes are diminished but not absent. Myasthenia gravis is an autoimmune disease in which antibodies to postsynaptic acetylcholine receptors block them from functioning. Tests include serology for antibodies to the acetylcholine receptor (AChR-Ab) or to muscle specific receptor tyrosine kinase (MuSK-Ab). EMG is the diagnostic test of choice. If required, treatment may include pyridostigmine, steroids, plasmapheresis, or worst-case scenario, a thymectomy to permanently get rid of the antibodies.

PEARLS: The diagnostic and screening tests are listed above, but DO NOT order them for a “best next step” question. For those, look for respiratory compromise or other complications that may require an immediate intervention (e.g., intubation due to severe weakness, tachypnea or shallow respirations). If the question specifically asks you about how to DIAGNOSE the patient, the answer will likely be EMG.

PEARL: There is a strong association with THYMOMA. Always look for it in MG patients. So, another “next step” answer could be to get quantitative immunoglobulins or imaging (CT, MRI, or X-ray of the chest).

PEARL: Congenital myasthenia gravis is a lifelong problem, and patients will have ptosis. Babies can also have a TRANSIENT myasthenia gravis due to maternal antibodies. This does not include ptosis and resolves after about 6 months.

(DOUBLE TAKE) CLOSTRIDIUM BOTULINUM

Clostridium botulinum is a gram-positive organism. The most common sources of botulism are food (think “bulging cans”) and wound infections. Look for a child less than 6 months of age with progressive descending weakness. It can progress from progressive ptosis and a poor suck to urinary retention within hours. The botulism toxin inhibits release of acetylcholine into the neurosynaptic junction. Treatment involves either supportive care (intubate if needed) or the antitoxin if it’s available.

PEARLS: For the exam, progressive ptosis in a baby probably means botulism! Children are usually less than 6 months of age since they are too young at that age to prevent colonization in the gut. This is why honey should not be given to infants < 1 year old.

(DOUBLE TAKE) CORYNEBACTERIUM DIPHTHERIAE

Corynebacterium diphtheriae is a gram-positive rod that can cause diphtheria. It starts off with a low fever and URI symptoms, including a sore throat. Eventually a pseudomembrane forms on the tonsils and pharynx. The swelling can be so bad that intubation is needed. It can also cause motor and sensory problems along with a loss of reflexes. The D in DTaP is for Diphtheria, so it’s no longer seen in the U.S. but could be seen in a child of immigrant status. Treat with erythromycin or penicillin G.

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