​Symptoms and Signs – Differential Diagnosis of Low-Voltage Electrocardiogram (ECG)
• Amyloidosis
• Anasarca
• Aortic stenosis
• Hypothyroidism
• Obesity
• Pericardial effusion
• Pleural effusion
• Pneumothorax

​Symptoms and Signs – Differential Diagnosis of Lumbar Disk Syndrome
• Degenerative arthritis of hip
• Insufficiency fracture of hip or pelvis
• Soft tissue strain or sprain
• Tumor

​Symptoms and Signs – Differential Diagnosis of Primary  Lung Neoplasm
• Benign lesions that simulate thoracic malignant disease
• Carcinoid tumor
• Granulomatous disease
• Lobar atelectasis: pneumonia, TB, chronic inflammatory disease, allergic bronchopulmonary aspergillosis
• Lung abscess
• Mediastinal adenopathy: sarcoidosis, lymphoma, primary TB, fungal disease, silicosis, pneumoconiosis, drug induced (e.g., phenytoin, trimethadione)
• Metastatic carcinoma to the lung
• Multiple pulmonary nodules: septic emboli, Wegener’s granulomatosis, sarcoidosis, rheumatoid nodules, fungal disease, multiple pulmonary atrioventricular fistulas
• Mycobacterial and fungal diseases
• Pleural effusion: congestive heart failure, pneumonia with parapneumonic effusion, TB, viral pneumonitis, ascites, pancreatitis, collagen-vascular disease
• Pneumonia
• Sarcoidosis
• Tuberculosis (TB)
• Viral pneumonitis

​Symptoms and Signs – Differential Diagnosis of Lyme Disease
• Acute viral illnesses
• Babesiosis
• Ehrlichiosis
• Erythema annulare
• Erythema marginatum
• Granuloma annulare
• Insect bite
• Seborrheic dermatitis

​Symptoms and Signs – Differential Diagnosis of Lymphadenopathy
GENERALIZED
• AIDS
• Lymphoma: Hodgkin’s disease, non-Hodgkin’s lymphoma
• Leukemias, reticuloendotheliosis
• Infectious mononucleosis, cytomegalovirus (CMV) and other viral infections
• Diffuse skin infection: generalized furunculosis, multiple tick bites
• Parasitic infections: toxoplasmosis, filariasis, leishmaniasis,
Chagas’ disease
• Serum sickness
• Collagen-vascular diseases (rheumatoid arthritis [RA], systemic
lupus erythematosus [SLE])
• Sarcoidosis and other granulomatous diseases
• Dengue (arbovirus infection)
• Drugs: isonicotinic acid hydrazide (INH), hydantoin derivatives,
antithyroid and antileprosy drugs
• Secondary syphilis
• Hyperthyroidism, lipid storage diseases
LOCALIZED
Cervical Nodes
• Infections of the head, neck, ears, sinuses, scalp, pharynx
• Mononucleosis
• Lymphoma
• TB
• Malignant neoplasm of head and neck
• Rubella
Scalene/Supraclavicular Nodes
• Lymphoma
• Lung neoplasm
• Bacterial or fungal infection of thorax or retroperitoneum
• GI malignant disease
Axillary Nodes
• Infections of hands and arms
• Cat-scratch disease
• Neoplasm (lymphoma, melanoma, breast carcinoma)
• Brucellosis
Epitrochlear Nodes
• Infections of the hand
• Lymphoma
• Tularemia
• Sarcoidosis, secondary syphilis (usually bilateral)
Inguinal Nodes
• Infections of leg or foot, folliculitis (pubic hair)
• Lymphogranuloma venereum (LGV), syphilis
• Lymphoma
• Pelvic malignant neoplasm
• Pasteurella pestis
Hilar Nodes
• Sarcoidosis
• TB
• Lung carcinoma
• Fungal infections, systemic
Mediastinal Nodes
• Sarcoidosis
• Lymphoma
• Lung neoplasm
• TB
• Mononucleosis
• Histoplasmosis
Abdominal/Retroperitoneal Nodes
• Lymphoma
• TB
• Exclude other causes of edema (e.g., cirrhosis, nephrosis, congestive heart failure, myxedema, hypoalbuminemia, chronic venous stasis, reflex sympathetic dystrophy, obstruction from abdominal or pelvic malignant neoplasm)
• Neoplasm (ovary, testes, prostate, and other malignant neoplasms)

​Symptoms and Signs – Differential Diagnosis of Leprosy
• Carpal tunnel syndrome
• Cutaneous leishmaniasis
• Fungal infections
• Lymphomatoid granulomatosis
• Rheumatoid arthritis
• Sarcoidosis
• Systemic lupus erythematosus

​Symptoms and Signs – Differential Diagnosis of Leptomeningeal Lesions
• Bacterial or viral meningitis
• Fungal infections (e.g., Cryptococcus)
• Histiocytosis
• Lyme disease
• Metastases
• Multiple sclerosis
• Neurocysticercosis
• Rheumatoid nodules
• Sarcoidosis
• Tuberculosis
• Vasculitis
• Wegener’s granulomatosis

​Symptoms and Signs – Differential Diagnosis of Leptospirosis
• Bacterial meningitis
• Influenza
• Legionnaire’s disease
• Viral hepatitis

​Symptoms and Signs – Differential Diagnosis of Leukocoria
• Cataract
• Familial exudative vitreoretinopathy
• Retinal detachment
• Retinal telangiectasia
• Retinoblastoma
• Retrolenticular vascularized membrane

​Symptoms and  Signs – Differential Diagnosis of  Korsakoff’s Psychosis
• Stroke affecting the temporal lobes or hippocampus
• Trauma affecting the temporal lobes or hippocampus
• Tumor affecting the temporal lobes or hippocampus
• Cerebral anoxia
• Transient global amnesia
• Dementing illness