A
- Aarskog-Scott syndrome
- AAT deficiency
- Abdominal cramps
- Abdominal hernia
- Abdominal muscle strain
- Abdominal wall defect
- Abductor spasmodic dysphonia
- Ablatio placentae
- Abruptio placentae
- Abscess, cutaneous
- Abscess, skin
- Abscessed tooth
- Absent menses
- Absent periods
- Absent pulmonary valve - child
- Abstinence syndrome
- Acanthosis nigricans
- Acetaminophen overdose
- Acetaminophen poisoning
- Achalasia
- Achilles' tendonitis
- Achilles' tendinopathy
- Achilles' tendinosis
- Achilles tendon rupture
- Achondroplasia
- Achondroplastic dwarfism
- ACL injury
- Acne
- Acne conglobata
- Acne inversa
- Acne vulgaris
- Acoustic neuroma
- Acrochordons
- Acromegaly
- ACS
- ACS (Acute compartment syndrome)
- ACS (Acute coronary syndrome)
- Actinic keratosis
- Actinomycosis
- Acute abdomen
- Acute abdominal pain
- Acute adrenocortical insufficiency
- Acute angle-closure glaucoma
- Acute autoimmune neuropathy
- Acute central cord syndrome
- Acute cerebellar ataxia
- Acute colonic diverticulitis
- Acute colonic pseudo-obstruction
- Acute compartment syndrome
- Acute coronary syndrome
- Acute diverticulitis
- Acute granulocytic leukemia - adult
- Acute granulocytic leukemia - child
- Acute idiopathic polyneuritis
- Acute inflammatory demyelinating polyneuropathy
- Acute inflammatory demyelinating polyradiculoneuropathy
- Acute inflammatory polyneuropathy
- Acute interstitial nephritis
- Acute lymphoblastic leukemia
- Acute lymphocytic leukemia
- Acute myeloblastic leukemia - adult
- Acute myeloblastic leukemia - child
- Acute myelogenous leukemia - adult
- Acute myelogenous leukemia - child
- Acute myeloid leukemia - adult
- Acute myeloid leukemia - child
- Acute myocardial infarction
- Acute necrotizing ulcerative gingivitis
- Acute nonbacterial gastroenteritis
- Acute nonlymphoblastic leukemia - adult
- Acute nonlymphoblastic leukemia - child
- Acute nontoxic megacolon
- Acute otitis
- Acute pancreatitis
- Acute renal failure
- Acute respiratory distress syndrome
- Acute silicosis
- Acute sinusitis
- Acute tubular necrosis
- AD
- Adamantiales-Behcet's syndrome
- ADC
- ADD
- Addison's disease
- Adductor laryngeal breathing dystonia (ABLD)
- Adductor spasmodic dysphonia
- Adenovirus infection
- ADHD
- Adhesive capsulitis
- Adjustment reaction disorder
- Adrenal cancer
- Adrenal crisis
- Adrenocortical carcinoma
- Adrenoleukodystrophy X-linked
- Adult macular degeneration
- Adult non-Hodgkin's lymphoma
- Adult polycystic disease
- Adult respiratory distress syndrome
- Adynamic ileus
- Aganglionic megacolon
- Age-related cramps
- Age-related hearing loss
- Agoraphobia
- Agranulocytosis
- AI
- AIDP
- AIDS
- AIDS dementia complex
- AIDS encephalopathy
- AIDS-related dementia
- Albinism
- ALCA - child
- Alcohol in pregnancy
- Alcoholism and alcohol abuse
- Alexia
- Alexic anomia
- Allergic bronchopulmonary aspergillosis
- Allergic contact dermatitis
- Allergic dermatitis
- Allergic rhinitis
- Allergy
- Allergy, nut
- Allergy, peanut
- Alopecia
- Alpha 1 anti-trypsin deficiency
- Alpha-1 antiprotease deficiency
- Alpha-galactosidase A deficiency
- ALS
- Altitude sickness
- Aluminum poisoning
- Aluminum toxicity
- Alzheimer's dementia
- Alzheimer's disease
- Amblyopia
- Amebiasis
- Amenorrhea
- AMI
- AML - child
- Amoebic dysentery
- Amyloid
- Amyloidosis
- Amyotrophic lateral sclerosis
- AN
- Anal abscess and anal fistula
- Anal atresia
- Anal cancer
- Anal fissure
- Anal itching
- Anal rectal abscess
- Anal rectal fistula
- Anankastic personality disorder
- Anaphylactoid purpura
- Anaphylaxis
- Anderson-Fabry disease
- Androblastoma
- Anemia
- Aneurysm, aortic
- Aneurysm, aortic (AAA)
- Aneurysm, aortic (abdominal aortic aneurysm)
- Aneurysm, aortic (thoracic aortic aneurysm)
- Aneurysm, brain
- Aneurysm, cerebral
- Aneurysm, intracerebral
- Aneurysm, intracranial
- Angina
- Angina pectoris
- Angiodysplasia of the colon
- Angioedema
- Angiokeratoma corporis diffusum
- Angiokeratoma diffuse
- Angioneurotic edema
- Angle-closure glaucoma
- Animal bites
- Ankle fracture
- Ankle sprain
- Ankylosing spondylitis
- Anogenital wart
- Anomalous left coronary artery - child
- Anomaly, Ebstein's - child
- Anomia, aphasia-associated
- Anomic aphasia
- Anorectal abscess
- Anorectal fistula
- Anorectal malfunction
- Anorexia nervosa
- Anoxic brain damage
- Anoxic brain injury
- Anserine tendinobursitis syndrome
- Anserine tendonitis
- Anterior cruciate ligament injury
- Anterior uveitis
- Anthrax
- Antibiotic-associated colitis
- Antibiotic-associated diarrhea
- Antisocial personality disorder
- ANUG
- Anxiety disorders
- Anxiety disorders
- Aortic aneurysm
- Aortic aneurysm (AAA)
- Aortic aneurysm (abdominal aortic aneurysm)
- Aortic aneurysm (thoracic aortic aneurysm)
- Aortic coarctation - adult
- Aortic coarctation - child
- Aortic dissection
- Aortic incompetence
- Aortic insufficiency
- Aortic regurgitation
- Aortic stenosis - adult
- Aortic stenosis - child
- Aphasia
- Aphasia-associated anomia
- Aphonia
- Aphthous ulcer
- Apocrine acne
- Apocrinitis
- Apoplexy
- Appendicitis
- Apraxia
- ARD
- ARDS
- Arnold-Chiari malformation
- Arnold-Chiari syndrome
- Arrhenoblastoma
- Arrhythmias
- Arsenic toxicity
- Arteriosclerosis obliterans
- Arteriosclerotic dementia
- Arteriovenous malformations
- Arteriovenous malformations of the brain
- Arteriovenous malformations of the colon
- Arthritis, gouty
- Arthritis, osteo-
- Arthritis, rheumatoid
- Arthritis
- AS - adult
- AS - child
- Asbestosis
- Ascariasis
- Ascites
- ASD
- Aseptic meningitis
- Aseptic necrosis of the hip
- ASH - adult
- ASH - child
- Asperger syndrome
- Aspergillosis
- Aspiration pneumonia
- Asthma
- Astigmatism
- Astrocytoma
- Asymmetric septal hypertrophy - adult
- Asymmetric septal hypertrophy - child
- Atelectasis
- Atherosclerosis
- Atherosclerotic disease
- Athlete's foot
- Atopic dermatitis
- Atrial fibrillation
- Atrial flutter
- Atrial septal defect
- Atrioventricular (AV) block - adult
- Atrioventricular canal defect
- Atrioventricular canal defect - child
- Atrioventricular septal defect
- Atrophic vaginitis
- Attention deficit disorder
- Attention deficit hyperactivity disorder
- Auditory dyssynchrony
- Auditory neuropathy
- Auditory processing disorder
- Auditory synaptopothy
- Autism
- Autoimmune hemolytic anemia
- Autonomic dysreflexia
- Autosomal dominant polycystic kidney disease
- AV canal defect - child
- Avascular necrosis
- Avian influenza