Makindo Medical Notes

Related Subjects: |Neurological History taking |Cortical functions |Motor System |Sensory System |Mental state Examination |Speech and Language Exam |Cranial nerves and examination |Assessing Cognition

It is crucial to take a detailed history and establish a timeline of problems as they arise. Neurological diagnosis relies 90% on history, supplemented by signs, imaging, and other tests.

Location, Causation, Confirmation, Explanation, Treatment

• Location: Identify where the lesion is, using history, clinical signs, and neuroanatomical knowledge.
• Causation: Determine what the lesion is. Consider onset speed, periodicity, patient age, and risk factors.
• Confirmation: Use imaging, neurophysiology, and genetic tests wisely to support the diagnosis.
• Explanation: Share information with the patient and involve them in ongoing management.
• Treatment: Determine if the condition is treatable, untreatable, or unmanageable (e.g., surgery too risky).

Symptoms, Sign Timings, and Periodicity

• Seconds and Minutes:
  • Vascular events such as SAH, TIA, stroke (usually negative neurology).
  • Seizures (positive neurology).
• Hours to Days:
  • Inflammation (e.g., MS, ADEM, transverse myelitis).
  • Infection (e.g., viral encephalitis, meningitis).
• Weeks to Months:
  • Degenerative (e.g., motor neuron disease).
  • Malignant neoplasms (e.g., aggressive primary brain tumors, metastases).
  • Creutzfeldt-Jakob disease, subacute combined degeneration.
• Months to Years:
  • Degenerative diseases such as Alzheimer’s, Parkinson’s.
  • Slow-growing tumors (e.g., meningioma).

Symptom Duration and Periodicity

• Resolution to normal within minutes with later recurrences: Epilepsy, TIA.
• Worst at onset, then gradually improves over days/weeks: Stroke, multiple sclerosis, inflammatory conditions.
• Diurnal pattern:
  • Myasthenia gravis (worsens throughout the day).
  • Headache from space-occupying lesions (worse on waking).
• Episodes lasting days, followed by resolution and recurrence: Relapsing-remitting multiple sclerosis.

Levels of Damage and Clinical Findings

Cortical Level

• Psychological/Functional Disorders: Physical manifestations of psychiatric disease. Patients with functional disorders are genuine and require empathy, while malingerers deliberately fake symptoms.
• Cortex: Right cortex controls the left side of the body and vice versa. A right cortical lesion may cause contralateral face, arm, leg, trunk weakness, hemisensory loss, hemianopia, and cortical signs (e.g., dysphasia, alexia, acalculia, apraxias).
• Internal Capsule: Similar to cortical findings but without cortical signs.

Subcortical Level

• Basal Ganglia: Movement disorders (e.g., chorea, parkinsonism, hemiballismus), and dementia.
• Thalamus: Sensory nuclei; lesions can impair complex sensory functions, cause thalamic pain, or memory loss.

Brainstem Level

• Lesions here may cause contralateral hemiparesis/hemisensory loss with ipsilateral cranial nerve palsies.
• Midbrain: Involves cranial nerves III, IV, red nucleus, medial lemniscus, substantia nigra, corticospinal tracts, and reticular activating system.
• Pons: Involves cranial nerves V, VI, VII, VIII, and cerebellar connections.
• Medulla: Cranial nerves IX, X, XI, XII, with corticospinal fiber decussation.

Cerebellar Lesions

• Lateral Lesions: Ipsilateral cerebellar signs (e.g., limb coordination issues).
• Midline Lesions: Truncal ataxia.

Spinal Cord Lesions (from Foramen Magnum to L1/2)

• Above C5-T1: Quadriplegia due to arm and leg output loss.
• Below T1: Paraplegia with preserved arm function.
• Lesions may be partial, causing selective sensory or motor losses based on the affected tract.

Cauda Equina

• Damage to lower motor neuron (LMN) roots within the spinal canal.
• Symptoms include pain, sensory loss, and weakness in the affected root area, with bilateral leg weakness and absent reflexes.
• Signs of cauda equina syndrome include loss of anal tone and reduced anal reflex.

Anterior Horn Cell

• LMN weakness, muscle wasting, fasciculations, and reflex loss, often seen in motor neuron disease (MND).

Peripheral Nervous System (PNS)

• Nerve Roots: Dermatomal pain and localized LMN weakness with reflex loss.
• Peripheral Nerves: Generalized "glove and stocking" sensory loss, motor loss, autonomic involvement.
• Individual nerves may be affected with predictable patterns involving both sensory and motor symptoms.
• Neuromuscular Junction Disorders: (e.g., Myasthenia Gravis, Lambert-Eaton Myasthenic Syndrome) characterized by fatigable weakness, ptosis, and diplopia.
• Muscle Disorders: Muscle weakness, wasting, or pseudohypertrophy, often affecting general or respiratory muscles.