Accidental hypothermia

Achalasia

Achilles' tendinitis

Achondroplasia

Achondroplastic dwarfism

Acinetobacter

ACL injury

Acne

Acne conglobata

Acne inversa (AI)

Acoustic neuroma

Acrochordons

Acromegaly

Actinic keratosis

Actinomycosis

Acute abdomen

Acute abdominal pain

Acute adrenocortical insufficiency

Acute coronary syndrome

Acute cystitis

Acute granulocytic leukemia

Acute interstitial nephritis

Acute lymphoblastic leukemia

Acute lymphocytic leukemia

Acute myeloblastic leukemia

Acute myelogenous leukemia

Acute myeloid leukemia

Acute nonlymphoblastic leukemia

Acute respiratory distress syndrome

Acute silicosis

Acute tubular necrosis

Adamantiales-Behcet's syndrome

Addison's disease

Adenoviruses

Adhesive capsulitis

Adjustment reaction disorder

Adrenal cancer

Adrenal crisis

Adrenocortical carcinoma

Adrenoleukodystrophy

Adult macular degeneration

Adult onset diabetes (Type 2 Diabetes)

Adult polycystic disease

Adult respiratory distress syndrome (ARDS)

Adynamic ileus

AE

African trypanosomiasis

Aganglionic megacolon

Age-related hearing loss

Agoraphobia

Agranulocytosis

AIDS

Albinism

Alcoholism and alcohol abuse

Allergic bronchopulmonary aspergillosis

Allergic contact dermatitis

Allergic rhinitis

Allergy
Allergic contact dermatitis
Food allergy
Insect allergy
Seasonal allergy (Hay fever)

Alopecia

Alpha-galactosidase A deficiency

Altitude sickness

Aluminum poisoning

Aluminum toxicity

Alveolar Echinococcosis

Alzheimer's disease

Amblyopia

Amebiasis

Amenorrhea

Amoebic dysentery

Amyloid

Amyloidosis

Amyotrophic lateral sclerosis (ALS)

Anal abscess and anal fistula

Anal atresia

Anal itching

Anal fissure

Anal rectal abcess

Anal rectal fistula

Anaphylactoid purpura

Anaphylaxis

Ancylostoma Infection

Anderson-Fabry disease

Androblastoma

Anemia
Anemia of chronic disease
Anemia of inflammation
Aplastic anemia
Iron-deficiency anemia
Macrocytic achylic anemia
Pernicious anemia
Sickle cell anemia

Aneurysm, aortic

Angina

Angiodysplasia of the colon

Angioedema

Angioneurotic edema

Angiostrongylus Cantonensis Infection

Anorectal abscess

Anorectal fistula

Anorectal malfunction

Antibiotic-associated colitis

Antibiotic-associated diarrhea

Angiokeratoma corporis diffusum

Angiokeratoma diffuse

Animal bites

Ankle fracture

Ankle sprain

Ankylosing spondylitis

Anorexia nervosa and Bulimia

Anoxic brain damage

Anoxic brain injury

Anterior cruciate ligament (ACL) injury

Antisocial personality disorder

Anthrax

Anxiety

Aortic aneurysm

Aortic dissection

Aortic regurgitation

Aortic stenosis

Aphasia

Aphthous ulcer

Apocrine acne

Apocrinitis

Apoplexy

Appendicitis

ARDS

Arenaviruses

Arrhenoblastoma

Arrhythmias

Arsenic toxicity

Arteriolar nephrosclerosis

Arteriosclerosis obliterans

Arteriovenous malformations

Arteriovenous malformations of the brain

Arteriovenous malformations of the colon

Arthritis
Fibromyalgia
Osteoarthritis
Gout
Rheumatoid
Systemic Lupus Erythematosus

Asbestosis

Ascariasis

Ascites

Aseptic meningitis

Aseptic necrosis of the hip

Asperger syndrome

Aspergillosis

Aspiration pneumonia

Asthma

Astigmatism

Astrocytoma

Atelectasis

Atherosclerosis

Athlete's foot

Atopic dermatitis

Atrial fibrillation

Atrial flutter

Atrial septal defect

Atrioventricular canal defect

Atrioventricular septal defect

Atrophic vaginitis

Attention deficit hyperactivity disorder (ADHD)

Atypical Autism

Autism

Autoimmune hemolytic anemia

Autosomal dominant polycystic kidney disease

Avascular necrosis

Avian influenza