Case Vignettes in Neurology

PATIENT CASE STUDIES

Case 31. (Pediatric Neurology Case 1)
Case discussion History: A six month old boy develops hypotonia of the neck and trunk muscles, constipation, and feeding difficulties. Over three days he progressively loses the ability to suck and swallow, which then results in aspiration. He had been a healthy infant who had received a breast milk diet until one month prior to this illness. At that time his diet was changed to homemade formula, infant cereal, and some other “baby foods.” Exam: The infant is intubated and has a flaccid paralysis of all four extremities. The reflexes are absent. There is ptosis, eye movements are reduced, and the pupillary responses to light are sluggish.
Summarize the Case in 1-2 sentences. A six month old boy with a one month history of progressive hypotonia of neck and trunk muscles, constipation and feeding difficulties, after changing from a breast fed diet to homemade formula, infant cereal and ãbaby foods,ä presents with a three day history of progressive loss of ability to suck or swallow and subsequent aspiration. The infant is intubated and exam reveals flaccid paralysis of all extremities, areflexia, ptosis, reduced EOMs, and sluggish pupillary responses to light. summary of course and physical signs is good; overall it is on the long side Discuss lesion localization on the basis of the physical examination. This disease process is a likely a disorder of the proximal musculature with descending paralysis of the extremities. why do you say proximal musculature? It seems from the exam that all you can say is that you suspect a problem in the PNS, ie nerve, nmj or muscle. Discuss underlying pathogenesis on the basis of clinical course. This is a subacute course consistent with an infectious process. ok Indicate one likely clinical diagnosis. List (or classify) alternative diagnoses. Probable: Infantile botulism Ddx: mysathenia gravis, carbon monoxide poisoning, Guillain-BarrŽ, poliomyelitis, anticholinergic toxicity, organophosphate poisoning dont give possible or probable; just indicate one clinical dx Indicate 2 ancillary tests that would assist in confirming or refuting the clinical diagnosis. Indicate the test results that would confirm the clinical diagnosis. Blood: Clostridium botulinum organisms, Stool Sample: C. botulinum cultured from feces EMG: diagnosis supported by characteristic small amplitude, brief polyphasic potentials with an incremental response to stimuli are seen Ð brief, small, abundant motor-unit action potentials (BSAP). Improvement in muscle function after administration of edrophonium bromide (Tensilon) would support myasthenia gravis. Examine food for organisms or toxins good; note the question asks for 2 tests not 3 Indicate complications of the disease and ancillary tests that would help evaluate them. Respiratory failure: Pulmonary function tests (how is this done with a six month old?) Aspiration pneumonia 2o to difficulty swallowing: CXR, ascultation good; in an infant you monitor for tachypnea, tachycardia, blood gases; paralysis is also a complication Discuss how the underlying pathophysiology is relevant in the management of this patient. Botulism is a paralytic disease caused by gram positive anaerobe, sporeforming bacillus Clostridium botulinum normally found in soil. The organism produces a potent polypeptide neurotoxin 0.1 ug LD50. Food born botulism results from ingesting the toxin or spore containing containing food. In infants, honey is a common source of spores. The toxin is absorbed from the gut and produces paralysis by preventing acetylcholine release from cholinergic fibers at myoneural junctions. Breast feed infants have a higher risk of for food born botulism, perhaps because of lower intestinal pH and differing flora. Patients are treated with equine botulism antitoxin intramuscularly as soon as the diagnosis is made after skin testing for horse serum sensitivity. Supportive therapy consists of bed rest, fluid therapy, ventalitory support (if necessary) and administration of purgatives and high enemas. Some advocate the use of penicillin to eliminate organisms continuing to produce toxin within the GI tract. good: what is it that the toxin(s) bind to resulting in a disruption of function?

Case 31. (Pediatric Neurology Case 1)

Case discussion

History: A six month old boy develops hypotonia of the neck and trunk muscles, constipation, and feeding difficulties. Over three days he progressively loses the ability to suck and swallow, which then results in aspiration. He had been a healthy infant who had received a breast milk diet until one month prior to this illness. At that time his diet was changed to homemade formula, infant cereal, and some other “baby foods.”

Exam: The infant is intubated and has a flaccid paralysis of all four extremities. The reflexes are absent. There is ptosis, eye movements are reduced, and the pupillary responses to light are sluggish.

Summarize the Case in 1-2 sentences.

A six month old boy with a one month history of progressive hypotonia of neck and trunk muscles, constipation and feeding difficulties, after changing from a breast fed diet to homemade formula, infant cereal and ãbaby foods,ä presents with a three day history of progressive loss of ability to suck or swallow and subsequent aspiration. The infant is intubated and exam reveals flaccid paralysis of all extremities, areflexia, ptosis, reduced EOMs, and sluggish pupillary responses to light.

summary of course and physical signs is good; overall it is on the long side

Discuss lesion localization on the basis of the physical examination.

This disease process is a likely a disorder of the proximal musculature with descending paralysis of the extremities.

why do you say proximal musculature? It seems from the exam that all you can say is that you suspect a problem in the PNS, ie nerve, nmj or muscle.

Discuss underlying pathogenesis on the basis of clinical course.

This is a subacute course consistent with an infectious process.

Indicate one likely clinical diagnosis. List (or classify) alternative diagnoses.

Probable: Infantile botulism

Ddx: mysathenia gravis, carbon monoxide poisoning, Guillain-BarrŽ, poliomyelitis, anticholinergic toxicity, organophosphate poisoning

dont give possible or probable; just indicate one clinical dx

Indicate 2 ancillary tests that would assist in confirming or refuting the clinical diagnosis. Indicate the test results that would confirm the clinical diagnosis.

Blood: Clostridium botulinum organisms, Stool Sample: C. botulinum cultured from feces EMG: diagnosis supported by characteristic small amplitude, brief polyphasic potentials with an incremental response to stimuli are seen Ð brief, small, abundant motor-unit action potentials (BSAP). Improvement in muscle function after administration of edrophonium bromide (Tensilon) would support myasthenia gravis. Examine food for organisms or toxins

good; note the question asks for 2 tests not 3

Indicate complications of the disease and ancillary tests that would help evaluate them.

Respiratory failure: Pulmonary function tests (how is this done with a six month old?) Aspiration pneumonia 2o to difficulty swallowing: CXR, ascultation

good; in an infant you monitor for tachypnea, tachycardia, blood gases; paralysis is also a complication

Discuss how the underlying pathophysiology is relevant in the management of this patient.

Botulism is a paralytic disease caused by gram positive anaerobe, sporeforming bacillus Clostridium botulinum normally found in soil. The organism produces a potent polypeptide neurotoxin 0.1 ug LD50. Food born botulism results from ingesting the toxin or spore containing containing food. In infants, honey is a common source of spores. The toxin is absorbed from the gut and produces paralysis by preventing acetylcholine release from cholinergic fibers at myoneural junctions. Breast feed infants have a higher risk of for food born botulism, perhaps because of lower intestinal pH and differing flora. Patients are treated with equine botulism antitoxin intramuscularly as soon as the diagnosis is made after skin testing for horse serum sensitivity. Supportive therapy consists of bed rest, fluid therapy, ventalitory support (if necessary) and administration of purgatives and high enemas. Some advocate the use of penicillin to eliminate organisms continuing to produce toxin within the GI tract.

good: what is it that the toxin(s) bind to resulting in a disruption of function?