Study guide
10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders
ABIM Internal Medicine Exam
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1 Chapter 0: The ABIM Exam, Blueprint & Study Strategy
0.1 Exam Format, Question Types & the 2026 Blueprint 0.2 Eligibility, Registration, Fees & Exam-Day Logistics 0.3 Scoring, the Passing Standard & Score Reports 0.4 Building a Blueprint-Weighted Study Plan
2 Chapter 1: Cardiovascular Disease (14% of Exam)
1.1 Ischemic Heart Disease & Acute Coronary Syndromes 1.2 Antithrombotic Therapy, Secondary Prevention & Mechanical Complications of MI 1.3 Atrial Fibrillation, Atrial Flutter & Stroke Prevention 1.4 Supraventricular Tachycardias, Ventricular Arrhythmias & Bradycardias 1.5 Heart Failure: Classification, Staging & Guideline-Directed Medical Therapy 1.6 Device Therapy, HFpEF & the Cardiomyopathies 1.7 Valvular Heart Disease & Endocarditis Prophylaxis 1.8 Pericardial Disease & Acute Aortic Syndromes 1.9 Hypertension: Classification, Diagnosis & Secondary Causes 1.10 Hypertensive Crises & Dyslipidemia 1.11 Adult Congenital Heart Disease & Coarctation of the Aorta 1.12 Syncope: Reflex, Orthostatic & Cardiac Causes 1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection
3 Chapter 2: Endocrinology, Diabetes & Metabolism (9% of Exam)
2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy 2.2 Insulin Therapy, Hyperglycemic Emergencies & Chronic Complications 2.3 Thyroid Function Testing & Hypothyroidism 2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules 2.5 Adrenal & Pituitary Disorders 2.6 Hypercalcemia, Hypocalcemia & Disorders of Mineral Metabolism 2.7 Osteoporosis & Paget Disease of Bone 2.8 Ovarian, Testicular & Reproductive Endocrine Disorders 2.9 Hypoglycemia, Endocrine Tumors, Polyglandular Syndromes & Severe Hypertriglyceridemia
4 Chapter 3: Gastroenterology & Hepatology (9% of Exam)
3.1 Esophageal Disease 3.2 Stomach & Duodenal Disease and Gastrointestinal Hemorrhage 3.3 Inflammatory Bowel Disease 3.4 Celiac Disease & Irritable Bowel Syndrome 3.5 Diverticular Disease & Colorectal Cancer Screening 3.6 Viral Hepatitis, Steatotic & Alcohol-Associated Liver Disease 3.7 Cirrhosis & the Complications of Portal Hypertension 3.8 Acute Pancreatitis 3.9 Chronic Pancreatitis & Biliary Tract Disease 3.10 Inherited, Autoimmune & Drug-Induced Liver Disease 3.11 Small Intestinal Disease, Ischemia & Gastrointestinal Complications of HIV
5 Chapter 4: Infectious Disease (9% of Exam)
4.1 Lower Respiratory Tract Infections & Sepsis Syndromes 4.2 Viral Respiratory Pathogens & Tuberculosis 4.3 Central Nervous System Infections 4.4 Skin, Soft Tissue, Bone & Joint Infections 4.5 Infective Endocarditis & Cardiovascular Infection 4.6 Clostridioides difficile & Catheter-Related Bloodstream Infection 4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention 4.8 Opportunistic Infections & Sexually Transmitted Infections 4.9 Fever of Unknown Origin, Neutropenic Fever & Toxic Shock 4.10 Travel-Related Illness, Vector-Borne Disease & Outbreaks 4.11 Infection Prevention, Nosocomial Infection & Postexposure Prophylaxis 4.12 Rheumatic Fever, Poststreptococcal Disease, Enteric & Hepatic Infections
6 Chapter 5: Pulmonary Disease (9% of Exam)
5.1 COPD: Diagnosis, GOLD Classification & Initial Pharmacotherapy 5.2 Interventions That Reduce COPD Mortality & Exacerbation Management 5.3 Asthma: Diagnosis, Stepwise Therapy & Status Asthmaticus 5.4 Interstitial Lung Disease & Idiopathic Pulmonary Fibrosis 5.5 Sarcoidosis, Hypersensitivity Pneumonitis & Occupational Lung Disease 5.6 Pulmonary Embolism: Diagnosis, Risk Stratification & Anticoagulation 5.7 Pulmonary Hypertension & Sleep-Disordered Breathing 5.8 Acute Respiratory Distress Syndrome & Mechanical Ventilation 5.9 Pleural Disease, Empyema & Pneumothorax 5.10 Bronchiectasis, Cystic Fibrosis & Restrictive Lung Disease 5.11 Evaluation of Cough, Dyspnea, Hemoptysis & the Solitary Pulmonary Nodule
7 Chapter 6: Rheumatology & Orthopedics (9% of Exam)
6.1 Rheumatoid Arthritis: Diagnosis & Systemic Manifestations 6.2 Antirheumatic Pharmacotherapy & the Spondyloarthropathies 6.3 Gout: Pathophysiology & Acute Management 6.4 Urate-Lowering Therapy & Calcium Pyrophosphate Deposition Disease 6.5 Osteoarthritis 6.6 Systemic Lupus Erythematosus 6.7 Systemic Sclerosis, Sjogren Syndrome & Inflammatory Myopathies 6.8 The Vasculitides 6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries 6.10 Other Primary Rheumatic Disorders & Mixed Connective Tissue Disease 6.11 Osteonecrosis & Metabolic Bone Disease
8 Chapter 7: Hematology (6% of Exam)
7.1 Approach to Anemia & the Microcytic Anemias 7.2 Macrocytic, Normocytic & Hemolytic Anemias 7.3 Hemoglobinopathies, Thalassemias & Paroxysmal Nocturnal Hemoglobinuria 7.4 Platelet Disorders, Thrombocytopenia & the Bleeding Patient 7.5 Coagulation Factor Disorders, Thrombophilia & Anticoagulant Reversal 7.6 Acute Leukemias, Chronic Leukemias & Myeloproliferative Neoplasms 7.7 Lymphomas & Plasma Cell Disorders 7.8 Myelodysplastic Syndrome, Myeloproliferative Neoplasms & Porphyria 7.9 Transfusion Medicine & Late Complications of Transplantation
9 Chapter 8: Medical Oncology (6% of Exam)
8.1 Breast, Lung, Colorectal & Prostate Cancer 8.2 Oncologic Emergencies 8.3 Genitourinary & Gynecologic Malignancies 8.4 Head and Neck, Bone & Soft Tissue Cancer and Cancer of Unknown Primary 8.5 Complications of Cancer & Its Treatment 8.6 Cancer Prevention, Survivorship & Psychosocial Care
10 Chapter 9: Nephrology & Urology (6% of Exam)
9.1 Acute Kidney Injury: Staging, Etiology & Urine Microscopy 9.2 Glomerular Disorders & Nephrotic Syndrome 9.3 Nephritic Syndromes, RPGN & Indications for Renal Replacement Therapy 9.4 Chronic Kidney Disease: Staging & Progression Retardation 9.5 Complications of Chronic Kidney Disease: Anemia, CKD-MBD & Acidosis 9.6 Hyponatremia, Hypernatremia & Water Balance 9.7 Potassium Disorders & Systematic Acid-Base Analysis 9.8 Renal Tubular Acidosis & Nephrolithiasis 9.9 Prostate Disorders, Urinary Incontinence & Other Urologic Conditions 9.10 Cystic Kidney Disease, Obstructive Uropathy, Tubulointerstitial Disease & Hematuria
11 Chapter 10: Neurology (4% of Exam)
10.1 Acute Ischemic Stroke: Syndromes & Reperfusion 10.2 Transient Ischemic Attack, Secondary Prevention & Hemorrhagic Stroke 10.3 Headache & Facial Pain 10.4 Seizures, Epilepsy & Movement Disorders 10.5 Multiple Sclerosis & Neuromuscular Junction Disorders 10.6 Motor Neuron Disease & Acute Peripheral Neuropathy 10.7 Cranial Neuropathies & Neuro-Ophthalmology 10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders
12 Chapter 11: Psychiatry & Behavioral Health (4% of Exam)
11.1 Major Depressive Disorder & Medical Mimics 11.2 Antidepressant Pharmacotherapy & Treatment-Resistant Depression 11.3 Bipolar Disorder, Mood Stabilizers & Lithium Toxicity 11.4 Anxiety, Stress-Related & Obsessive-Compulsive Disorders 11.5 Alcohol Use Disorder & Withdrawal 11.6 Pharmacotherapy for Alcohol & Opioid Use Disorder 11.7 Toxidromes, Psychiatric Emergencies & Suicide Risk Assessment 11.8 Psychotic, Somatic Symptom, Factitious & Personality Disorders 11.9 Eating Disorders, Sleep Disorders & Sexual Health
13 Chapter 12: Dermatology (3% of Exam)
12.1 Dermatitis, Papulosquamous & Inflammatory Dermatoses 12.2 Acne, Rosacea & Cutaneous Infections 12.3 Herpes Zoster & Autoimmune Blistering Diseases 12.4 Nodules, Tumors & Cutaneous Oncology 12.5 Dermatologic Emergencies & Severe Cutaneous Adverse Reactions 12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity 12.7 Vascular Dermatoses, Environmental Injury & Cutaneous Signs of Systemic Disease
14 Chapter 13: Obstetrics & Gynecology / Women's Health (3% of Exam)
13.1 Contraception, Preconception Care & Teratogenicity 13.2 Hypertensive Disorders of Pregnancy & Gestational Diabetes 13.3 Thyroid Disease & Venous Thromboembolism in Pregnancy 13.4 Menopause & Menopausal Hormone Therapy 13.5 Abnormal Uterine Bleeding, Endometrial Disease & Gynecologic Cancer Screening 13.6 Breast Disorders & Diseases of the Vulva and Vagina 13.7 Menstrual Disorders, Fibroids, Endometriosis & Early Pregnancy Complications
15 Chapter 14: Geriatric Syndromes (3% of Exam)
14.1 Comprehensive Geriatric Assessment & Frailty 14.2 Falls, Gait Assessment & Polypharmacy 14.3 Urinary Incontinence & Pressure Injuries in Older Adults 14.4 Mild Cognitive Impairment, Dementia & Its Subtypes 14.5 Delirium & the Pharmacotherapy of Cognitive Disorders 14.6 Palliative Care, Hospice & Advance Care Planning 14.7 Chronic Wounds, Nutrition, Swallowing, Constipation & Hip Fracture 14.8 Sensory Impairment, Dizziness, Elder Mistreatment & Care Settings
16 Chapter 15: Allergy & Immunology (2% of Exam)
15.1 Anaphylaxis: Recognition & Emergency Management 15.2 Urticaria & Angioedema 15.3 Drug Allergy, Desensitization & Adult Immunodeficiency 15.4 Food Allergy, Insect Venom Hypersensitivity, Serum Sickness & Contrast Reactions 15.5 Rhinitis, Conjunctivitis, Eosinophilic & Mast Cell Disorders
17 Chapter 16: Preventive Medicine, Immunization & Clinical Epidemiology
16.1 The USPSTF Framework & Evidence-Based Cancer Screening 16.2 Cardiovascular & Metabolic Screening and Primary Prevention 16.3 Adult Immunization & Vaccines in Special Populations 16.4 Clinical Epidemiology, Biostatistics & Study Design
18 Chapter 17: Miscellaneous - Ethics, Patient Safety & Quality Improvement (2% of Exam)
17.1 Principles of Bioethics & Decisional Capacity 17.2 Informed Consent, Treatment Refusal & Special Scenarios 17.3 Surrogate Decision-Making, Advance Directives & Confidentiality 17.4 Patient Safety Science, Medical Error & Diagnostic Reasoning 17.5 Quality Improvement Methods, Health Disparities & Health Equity
19 Chapter 18: Perioperative Medicine & Medical Consultation
18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications
20 Chapter 19: Ophthalmology (1% of Exam)
19.1 The Acute Red Eye & Ophthalmic Emergencies 19.2 Painless Vision Loss & Chronic Ophthalmic Disease 19.3 Uveitis, Scleritis & Orbital Disease
21 Chapter 20: Otolaryngology & Dental Medicine (1% of Exam)
20.1 Dizziness, Vertigo & Epistaxis 20.2 Ear Disorders, Hearing Loss & Upper Respiratory Infections 20.3 Oral Cavity, Salivary Gland, Laryngeal & Taste and Smell Disorders
10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders
Key Takeaways Explain This Topic AI
Carpal tunnel and other entrapment neuropathies, meralgia paresthetica, fibular neuropathy, diabetic neuropathy and postherpetic neuralgia are enumerated under peripheral neuropathy.
Brain tumors, spinal cord tumors and compression, carcinomatous meningitis and paraneoplastic neurologic syndromes are enumerated under central nervous system tumors.
A symmetric stocking-glove distribution indicates length-dependent polyneuropathy, whereas a single nerve or root distribution indicates a focal lesion.
Diabetes is the most common cause of polyneuropathy, and initial testing for an unexplained neuropathy includes glucose, B12, thyroid function and serum protein electrophoresis.
New back pain with neurologic findings in a patient with known malignancy requires immediate corticosteroids and urgent magnetic resonance imaging of the whole spine.
Last updated: August 2026
1. Classifying Neuropathy
The first question is distribution , because it separates entirely different differentials.
Pattern Meaning Examples
Symmetric distal (stocking-glove) Length-dependent polyneuropathy Diabetes , alcohol, B12 deficiency, chemotherapy, uremia, hypothyroidism, HIV
Single nerve Mononeuropathy Carpal tunnel, fibular neuropathy, meralgia paresthetica
Multiple named nerves, asymmetric Mononeuritis multiplex Vasculitis , diabetes, sarcoidosis, amyloidosis, leprosy
- Dermatomal Radiculopathy Disc herniation, zoster
- Ascending, areflexic, acute Polyradiculoneuropathy Guillain-Barre syndrome
Mononeuritis multiplex is the red-flag pattern. Stepwise involvement of individually named nerves signals a vasculitic process — polyarteritis nodosa, ANCA-associated vasculitis, cryoglobulinemia — and requires urgent evaluation, since untreated vasculitic neuropathy causes permanent deficits.
Initial laboratory evaluation of an unexplained polyneuropathy: fasting glucose or hemoglobin A1c (with an oral glucose tolerance test if impaired glucose tolerance is suspected), vitamin B12 with methylmalonic acid , thyroid-stimulating hormone, complete blood count, comprehensive metabolic panel and serum protein electrophoresis with immunofixation to detect a monoclonal gammopathy.
2. Common Entrapment Neuropathies
Neuropathy Nerve Features Management
Carpal tunnel Median at the wrist Nocturnal paresthesia in the thumb, index, middle and radial ring finger; thenar wasting late; palmar sensation spared (palmar cutaneous branch passes above the tunnel) Nocturnal neutral splinting first-line; steroid injection; surgery for refractory or motor involvement
Ulnar at the elbow Ulnar Numbness of the fourth and fifth fingers, weak grip, interosseous wasting Elbow padding, avoid prolonged flexion
Fibular (peroneal) at the fibular head Common fibular Foot drop with weak eversion, sensory loss over the dorsum of the foot; inversion preserved Avoid leg crossing and compression; brace
Meralgia paresthetica Lateral femoral cutaneous Purely sensory burning over the anterolateral thigh; no weakness, no reflex change Weight loss, avoid tight belts; reassurance
Two discriminations the exam uses:
Carpal tunnel syndrome spares palmar sensation , because the palmar cutaneous branch of the median nerve arises proximal to the tunnel. Numbness of the whole palm suggests a more proximal median lesion or a C6-C7 radiculopathy.
Foot drop from fibular neuropathy preserves inversion (tibial nerve). Foot drop with weak inversion implicates the L5 root , not the fibular nerve.
Carpal tunnel associations that should be sought: pregnancy, hypothyroidism, diabetes, obesity, rheumatoid arthritis, acromegaly and amyloidosis — bilateral carpal tunnel syndrome in an older man with cardiac findings should raise transthyretin amyloidosis.
3. Diabetic and Painful Neuropathies
Diabetic polyneuropathy is the most common neuropathy in developed countries: symmetric, distal, sensory-predominant, with burning pain, numbness and loss of ankle reflexes and vibration sense. Complications include painless foot ulceration and Charcot neuroarthropathy , which is why annual monofilament foot examination matters.
Diabetic autonomic neuropathy produces gastroparesis, orthostatic hypotension without compensatory tachycardia, erectile dysfunction, and silent myocardial ischemia .
Diabetic amyotrophy (lumbosacral radiculoplexus neuropathy) causes severe unilateral thigh pain with proximal weakness and weight loss, and typically improves over months.
Treatment of painful neuropathy: glycemic control slows progression in type 1 diabetes but has limited effect in type 2. Symptomatic agents include duloxetine, pregabalin, gabapentin and tricyclic antidepressants . Opioids are not first-line and are avoided for chronic neuropathic pain.
Postherpetic neuralgia — an enumerated blueprint topic — is pain persisting beyond about three months after the zoster rash. Risk rises steeply with age. Recombinant zoster vaccination is the primary prevention , and prompt antiviral treatment of acute zoster reduces, but does not eliminate, the risk. Treatment uses gabapentinoids, tricyclics and topical lidocaine.
4. Central Nervous System Tumors
Enumerated under both Neurology and Medical Oncology, listing brain tumors, spinal cord tumors and compression, carcinomatous meningitis and paraneoplastic syndromes.
In adults, metastases outnumber primary brain tumors , arising most often from lung, breast, melanoma, renal and colorectal primaries; melanoma metastases are notably prone to hemorrhage.
Presentations: progressive headache that is worse in the morning or with Valsalva , new-onset seizure in an adult, progressive focal deficit, or personality change. Corticosteroids reduce vasogenic edema and often produce rapid symptomatic improvement, but should be deferred when primary CNS lymphoma is suspected until tissue is obtained, because steroids can transiently dissolve the lesion and render biopsy non-diagnostic.
Carcinomatous (leptomeningeal) meningitis presents with multifocal neurologic findings at different levels of the neuraxis — cranial neuropathies plus radicular symptoms plus headache — and is diagnosed by cerebrospinal fluid cytology, which frequently requires repeated large-volume sampling, with MRI of the whole neuraxis.
Malignant spinal cord compression is the emergency in this group. New or worsening back pain in a patient with known cancer is cord compression until proven otherwise. Pain typically precedes neurologic findings by weeks — that interval is the opportunity. Give corticosteroids immediately on suspicion and obtain urgent MRI of the entire spine , since multiple non-contiguous levels are common. Neurologic status at the time of treatment is the strongest predictor of eventual ambulation.
Paraneoplastic neurologic syndromes include Lambert-Eaton myasthenic syndrome, paraneoplastic cerebellar degeneration, limbic and other autoimmune encephalitis, and opsoclonus-myoclonus; they may precede the cancer diagnosis by months and warrant a directed tumor search.
5. Disorders of Cerebral Function
Enumerated as dementia, aphasia and medical causes of delirium . Dementia and delirium are covered in the geriatrics chapter; the aphasia syndromes are worth a table because they localize precisely.
- Aphasia Fluency Comprehension Repetition Localization
- Broca Non-fluent Intact Impaired Inferior frontal gyrus
- Wernicke Fluent but meaningless Impaired Impaired Superior temporal gyrus
- Conduction Fluent Intact Impaired out of proportion Arcuate fasciculus
- Global Non-fluent Impaired Impaired Large dominant hemisphere lesion
- Transcortical Variable Variable Preserved Watershed territory
Wernicke aphasia is frequently mistaken for delirium or psychosis , because the patient speaks fluently but nonsensically and cannot follow commands. The clue is that other cognitive domains and the level of consciousness are intact.
6. Other Neurologic Disorders
A named blueprint subsection listing neurocutaneous syndromes, head injury, spinal cord injury and disorders, idiopathic intracranial hypertension, motor neuron disease, neuroleptic malignant syndrome and cerebellar ataxias.
Head injury
Concussion is a clinical diagnosis with normal imaging. Most symptoms resolve within days to weeks; a graduated return-to-activity protocol is used and an athlete should never return to play on the day of injury .
Chronic subdural hematoma is the diagnosis not to miss in older adults: weeks of progressive confusion, headache or gait disturbance after trivial or forgotten trauma , with anticoagulation, alcohol use and cerebral atrophy as risk factors. It is a reversible cause of cognitive decline and is the reason neuroimaging is included in a dementia workup.
Epidural hematoma classically follows temporal bone fracture with middle meningeal artery injury and a lucid interval ; it is a neurosurgical emergency.
Spinal cord disorders
Cord compression from tumor, epidural abscess, hematoma or disc requires emergent MRI. Cauda equina syndrome — urinary retention (the most sensitive finding), saddle anesthesia, bilateral leg weakness, decreased rectal tone — requires emergent imaging and decompression.
Subacute combined degeneration from vitamin B12 deficiency damages the dorsal columns and corticospinal tracts, producing loss of vibration and proprioception with upper motor neuron signs and paradoxically absent ankle reflexes from coexisting neuropathy. It may occur without anemia or macrocytosis , and nitrous oxide exposure — including recreational use — can precipitate it. Copper deficiency produces a nearly identical myeloneuropathy.
Syringomyelia produces a cape-like dissociated sensory loss, with loss of pain and temperature but preserved light touch and proprioception, from involvement of the crossing spinothalamic fibers.
Cerebellar ataxias
Causes include alcohol (vermian degeneration with gait ataxia and relatively spared arms), phenytoin toxicity, Wernicke encephalopathy (ataxia, ophthalmoplegia and confusion — give thiamine before glucose ), paraneoplastic cerebellar degeneration, hypothyroidism, and hereditary ataxias including Friedreich ataxia and the spinocerebellar ataxias.
Neurocutaneous syndromes
Neurofibromatosis type 1 — cafe-au-lait macules, axillary and inguinal freckling, neurofibromas, Lisch nodules , optic glioma. Neurofibromatosis type 2 — bilateral vestibular schwannomas , meningiomas. Tuberous sclerosis — ash-leaf macules, facial angiofibromas, shagreen patch, seizures, subependymal nodules, renal angiomyolipomas. Sturge-Weber syndrome — port-wine stain in the trigeminal distribution with leptomeningeal angioma and seizures.