- C. Difficile Infection
- Calciphylaxis
- Cancer
- Cancer of Unknown Primary
- Canker Sore
- Capillary Leak Syndrome
- Carbon Monoxide Poisoning
- Carcinoid Syndrome
- Cardiogenic Shock
- Cardiomyopathy
- Carotid Artery Disease
- Carpal Tunnel Syndrome
- Castleman Disease
- Cataracts
- Cavernous Malformations
- Cavities/ Tooth Decay
- Celiac Disease
- Cellulite
- Cellulitis
- Central Sleep Apnea
- Cerebral Palsy
- Cervical Cancer
- Cervical Dysplasia
- Cervical Dystonia
- Cervical Spondylosis
- Cervicitis
- CGD
- Chagas Disease
- Charcot-Marie-Tooth Disease
- Chemo Brain
- Chest Pain
- Chiari Malformation
- Chickenpox
- Chilblains
- Child Abuse
- Child CHD
- Childhood Apraxia Of Speech
- Childhood Asthma
- Childhood Obesity
- Childhood Schizophrenia
- Childhood Sleep Apnea
- Chlamydia
- Cholecystitis
- Cholelithiasis
- Cholera
- Cholestasis Of Pregnancy
- Chondrosarcoma
- Chordoma
- Chronic Cough
- Chronic Daily Headaches
- Chronic Fatigue Syndrome
- Chronic Hives (Urticaria)
- Chronic Kidney Disease
- Chronic Pelvic Pain (Women)
- Chronic Sinusitis
- Churg-Strauss Syndrome
- Cirrhosis
- Claudication
- Cleft Lip And Cleft Palate
- Clubfoot
- Cluster Headache
- CMS Disorders
- CMV Infection
- CNS Vascular Malformations
- Coarctation Of The Aorta
- Cold Sore
- Cold Urticaria
- Colic
- Colon Cancer
- Colon Polyps
- Coma
- Common Cold
- Common Cold In Babies
- Common Variable Immunodeficiency (CVID)
- Common Warts
- Compartment Syndrome
- Complicated Grief
- Compression Headaches
- Compulsive Gambling
- Compulsive Sexual Behavior
- Concussion
- Congenital Myopathies
- Conjoined Twins
- Constipation
- Constipation In Children
- Contact Dermatitis
- Convergence Insufficiency
- Conversion Disorder
- COPD
- Corns And Calluses
- Coronary Artery Disease
- Corticobasal Degeneration
- Costochondritis
- Cough Headaches
- COVID-19
- Cradle Cap
- Craniopharyngioma
- Craniosynostosis
- CREST Syndrome
- Creutzfeldt-Jakob Disease
- Crohn’s Disease
- Croup
- Cryoglobulinemia
- Cryptosporidium Infection
- CTE
- Cushing Syndrome
- Cutaneous T-Cell Lymphoma
- Cyclic Vomiting Syndrome
- Cyclospora Infection
- Cyclothymia
- Cystic Fibrosis
- Cystitis
- Cysts