USMLE Step 2 CK Ep-2

Overview

A case of wound botulism was described with symptoms like descending paralysis, ptosis, sluggish pupils, and respiratory failure.
Diagnosis: Clinical suspicion confirmed by serum toxin analysis.
Management: Administer equine-derived antitoxin for adults and human-derived antitoxin for infants.
Types:
- Wound Botulism: Common in IV drug users, caused by spore germination in anaerobic conditions.
- Food Botulism:
  - Infant Type: From ingesting spores (e.g., honey).
  - Adult Type: From ingesting preformed toxin (e.g., improperly canned food).
Mechanism of Action: Botulinum toxin inhibits presynaptic acetylcholine release by cleaving SNARE proteins, causing descending paralysis.

Seen in rheumatoid arthritis patients after intubation.
Symptoms: Decreased muscle strength, hyperactive reflexes, and respiratory dysfunction due to vertebral artery compression.
Diagnosis: MRI of the cervical spine.
Management: Stabilize the cervical spine pre-intubation; cervical fixation may be required.

High-risk trauma or subtle cases assessed using NEXUS criteria (neurologic deficit, spinal tenderness, altered mental status, intoxication, distracting injury).
Imaging: CT scan preferred for cervical spine injury. Flexion-extension X-rays are used for ligamentous injury after ruling out fractures.

Presentation: Symptoms of mass effect, e.g., headaches, seizures, or neurological deficits.
Diagnosis: MRI with gadolinium enhancement.
Treatment: Complete surgical resection is curative in most cases.

Case: Burst fracture at C5 with spinal cord impingement.
Findings: Loss of pain and temperature sensation below clavicles.
Management: Evaluate airway, breathing, circulation; stabilize the spine; address neurogenic shock and spinal injury.

The episode emphasizes recognizing critical neurological presentations, prompt diagnosis, and evidence-based management tailored to the scenario.