# Clinical Cases: Neuroscience Overview and Neuroanatomy ## Case 1: Neural Tube Defect - Myelomeningocele ### Patient Presentation **Demographics:** Newborn male, delivered at 38 weeks gestation **Chief Complaint:** Prenatal diagnosis of spinal abnormality on routine ultrasound **History of Present Illness:** A 28-year-old primigravida underwent routine prenatal screening at 18 weeks gestation. Ultrasound revealed a cystic lesion in the lumbar spine region with splaying of the posterior vertebral elements. Alpha-fetoprotein levels were elevated in both maternal serum and amniotic fluid. The mother reported irregular prenatal care and had not been taking folic acid supplementation prior to conception. Fetal MRI confirmed myelomeningocele at L4-L5 level. The infant was delivered via cesarean section to minimize trauma to the exposed neural tissue. **Physical Examination:** - Alert, appropriate cry and suck reflex - Large open neural placode at the lower lumbar region measuring 4 cm x 5 cm with exposed neural tissue and leaking cerebrospinal fluid - Flaccid paralysis of bilateral lower extremities - Absent deep tendon reflexes in lower extremities - No response to pinprick below the level of the umbilicus - Urinary dribbling noted (neurogenic bladder) - Head circumference at 95th percentile with bulging anterior fontanelle **Workup:** - **Spinal ultrasound:** Confirmed myelomeningocele at L4-L5 - **Head ultrasound:** Revealed hydrocephalus with dilated lateral and third ventricles; Chiari II malformation with hindbrain herniation - **MRI spine and brain:** Confirmed lumbar myelomeningocele with associated tethered cord; Chiari II malformation with cerebellar tonsillar herniation through foramen magnum **Diagnosis:** Lumbar myelomeningocele with Chiari II malformation and hydrocephalus **Treatment:** - Emergency surgical closure of the myelomeningocele within 24 hours of birth - Ventriculoperitoneal shunt placement for hydrocephalus at 5 days of life - Clean intermittent catheterization initiated for neurogenic bladder - Physical therapy and orthopedic evaluation for lower extremity management - Genetic counseling for family regarding recurrence risk (3-5% without folate, reduced to <1% with supplementation) **Clinical Pearl:** Neural tube defects result from failure of neural tube closure during the fourth week of gestation. Folic acid supplementation (400 mcg daily) starting at least one month before conception reduces the risk by up to 70%. The level of the defect determines the extent of motor and sensory deficits below the lesion. --- ## Case 2: Subdural Hematoma ### Patient Presentation **Demographics:** 78-year-old male **Chief Complaint:** Progressive confusion and left-sided weakness over 3 weeks **History of Present Illness:** The patient's daughter noticed her father becoming increasingly forgetful and confused over the past 3 weeks. He was previously independent but now requires assistance with activities of daily living. She also noticed he was dragging his left leg when walking. On direct questioning, the patient recalled falling and hitting his head on a coffee table approximately 4 weeks ago. He did not lose consciousness and did not seek medical attention at the time. His medical history includes atrial fibrillation for which he takes warfarin. **Physical Examination:** - Vital signs: BP 158/92, HR 72 irregular, T 36.8C - General: Elderly male, mildly confused, knows name but not date - Neurological: - Mental status: Oriented to person only, follows simple commands inconsistently - Cranial nerves: Pupils equal and reactive; subtle left facial droop - Motor: Left upper extremity 4/5 strength, left lower extremity 4/5 strength, right side normal - Sensory: Intact to light touch bilaterally - Reflexes: Left-sided hyperreflexia with upgoing Babinski response **Workup:** - **CT head without contrast:** Large right-sided crescent-shaped extra-axial collection measuring 2 cm in maximum thickness with mixed density (acute and chronic blood), causing 8 mm rightward midline shift with effacement of right lateral ventricle - **INR:** 3.8 (supratherapeutic) - **Complete blood count:** Normal - **Basic metabolic panel:** Normal **Diagnosis:** Subacute-on-chronic subdural hematoma, right hemisphere **Treatment:** - Warfarin held; INR reversal with vitamin K 10 mg IV and 4-factor prothrombin complex concentrate (PCC) - Neurosurgical consultation for urgent evacuation - Burr hole drainage performed with evacuation of approximately 80 mL of mixed clot and liquefied blood - Post-operative CT showed resolution of midline shift - Gradual clinical improvement over 5 days with return to baseline mental status - Cardiology consultation for alternative anticoagulation strategy (left atrial appendage closure considered) **Clinical Pearl:** Subdural hematomas result from rupture of bridging veins in the subdural space. They appear crescent-shaped on CT because blood can spread along the cerebral convexity, unlike epidural hematomas which are limited by dural attachments at suture lines. Risk factors include advanced age (brain atrophy increases tension on bridging veins), anticoagulation, and trauma (often minor in elderly patients). --- ## Case 3: Uncal Herniation ### Patient Presentation **Demographics:** 45-year-old female **Chief Complaint:** Found unresponsive at home **History of Present Illness:** Emergency medical services were called when the patient's husband found her unresponsive in bed. He reported she had complained of "the worst headache of her life" approximately 2 hours earlier while they were watching television. She took ibuprofen and went to lie down. When he checked on her 30 minutes later, she was difficult to arouse. By the time EMS arrived, she was completely unresponsive. She has a history of hypertension and smokes one pack of cigarettes daily. **Physical Examination:** - Vital signs: BP 185/110, HR 58, RR irregular, T 37.2C - General: Unresponsive, GCS 6 (E1V2M3) - Neurological: - Right pupil 6 mm fixed and dilated; left pupil 3 mm reactive - No response to verbal commands - Withdraws left side to pain; right side extensor posturing (decerebrate response) - Corneal reflexes absent on right, present on left - No gag reflex **Workup:** - **CT head without contrast:** Diffuse subarachnoid hemorrhage concentrated in basal cisterns; 3 cm left temporal intracerebral hematoma with uncal herniation and effacement of perimesencephalic cistern; early hydrocephalus - **CT angiography:** 8 mm saccular aneurysm at left posterior communicating artery origin **Diagnosis:** Aneurysmal subarachnoid hemorrhage with intracerebral hematoma, uncal herniation, and CN III palsy **Treatment:** - Immediate intubation for airway protection - External ventricular drain (EVD) placement for ICP monitoring and CSF drainage - Osmotic therapy with mannitol 1 g/kg IV bolus - Emergency craniotomy with aneurysm clipping and hematoma evacuation - Post-operative care in neurocritical care unit with nimodipine for vasospasm prophylaxis - Gradual weaning from sedation; right pupil reactivity returned after decompression - Prolonged rehabilitation required; at 6-month follow-up, Modified Rankin Scale 3 **Clinical Pearl:** Uncal herniation occurs when increased intracranial pressure forces the medial temporal lobe (uncus) through the tentorial notch. This compresses the ipsilateral CN III (causing pupil dilation and ptosis), the cerebral peduncle (causing contralateral hemiparesis), and the posterior cerebral artery (causing visual field deficits). The classic triad of CN III palsy, contralateral hemiparesis, and decreased consciousness requires emergent intervention. --- ## Clinical Image ![Subdural hematoma CT](case_01_image.jpg) **Image Description:** Axial CT scan of the head demonstrating a crescent-shaped subdural hematoma along the right cerebral convexity, a characteristic finding in subdural hemorrhage resulting from torn bridging veins in the subdural space. **Attribution:** Image from Radiopaedia (https://radiopaedia.org/), Creative Commons Attribution-NonCommercial-ShareAlike 3.0 license.