Medical Quiz: Conjunctivitis and GI Conditions

Inflammatory Skin Conditions

• Acne (Acne vulgaris): Caused by increased sebum production and abnormal follicular keratinization. Androgens and anabolic steroids increase sebum, while estrogen decreases it. Diet and stress can also affect production. Bacteria can proliferate and cause inflammation.
• Atopic Dermatitis (Eczema): A chronic allergic hypersensitivity disease and immune dysfunction, primarily mediated by TH2 cells. This condition presents with dry, red, cracked, itchy, and weeping skin and is often associated with other atopic conditions, like asthma. Acute cases are triggered by allergens entering damaged skin, leading to inflammatory mediators release. Chronic cases are driven by T-cell cytokines and keratinocyte dysfunction causing skin thickening.
• Contact Dermatitis: Two types:
  • Irritant contact dermatitis: Direct irritation or injury by physical or chemical agents (e.g., ammonia in urine, proteolytic enzymes in feces, friction).
  • Allergic contact dermatitis: Immune response to small organic or inorganic allergens that can penetrate the skin, mediated by T-cell responses. Protein contact dermatitis is also an immune response but to large protein allergens and cannot penetrate intact skin.
• Cellulitis: An acute bacterial infection of the dermis and subcutaneous fat, commonly caused by Staphylococcus aureus or Streptococcus pyogenes. It often enters through a wound and presents as ill-defined red, painful, and swollen lesions. Systemic symptoms like fever and chills can also occur.
• Urticaria (Hives): Characterized by itchy wheals (hives) and/or dermal swelling (angioedema). It can be acute or chronic and results from mast cell degranulation-releasing histamine and other mediators. This leads to the characteristic weals and blisters.
• Psoriasis: Excessive proliferation and differentiation of keratinocytes. Stimuli may damage keratinocytes and trigger an immune response, resulting in inflammatory mediators and excessive skin cell growth. This manifests as plaques on the skin.

Infectious Skin Conditions

• Fungal Infections:
  • Tinea Pedis (Athlete's foot): Caused by T. rubrum, T. mentagrophytes, or Epidermophyton floccosum. It is a chronic recurrence that is common in immune-compromised or those with poor circulation. It presents as dry, scaly, itchy lesions and even nail infections (onychomycosis).
  • Tinea Corporis (Ringworm): Often zoonotic, and appears as inflamed red patches with white healing centers. It's distinguished by using a Wood's lamp (fungi will glow).
  • Tinea Capitis (Scalp infection): Presents as inflamed scalp, and hair loss. It is caused by Microsporum canis. Easily transmitted via spores in hairbrushes and clothing.
• Viral Infections:
  • Warts (Verruca vulgaris): Caused by human papillomavirus, can be contagious and spread from person to person or auto-inoculated.
  • Cold sores: Caused by Herpes simplex virus type 1 (HSV-1). It is a latent virus, with periodic reactivation and typically appears as red bumps, blisters that crust over and heal within 7 to 10 days.
  • Chickenpox: Caused by Varicella-zoster virus (VZV). Highly contagious and spread via respiratory droplets. It is characterized by a characteristic itchy rash of fluid-filled blisters that rupture, resulting in scabs.
• Bacterial Infections:
  • Hair follicle infections: Often caused by S. aureus but can be fungal. This condition typically affects moist and warm areas.
  • Folliculitis: Localized, small, inflamed pustules (often itchy and painful).
  • Boils (furunculosis): More severe, deeper infection of one or more follicles with larger inflammatory areas.
  • Carbuncle: A large collection of boils.

Other Skin Conditions

• Impetigo: Caused by Staphylococcus aureus or Streptococcus pyogenes, a superficial infection of the epidermis. Highly contagious, without systemic symptoms, self-resolving and often occurs around the nose and mouth
• Clostridial skin infections: Caused by C. tetani (tetanus) and C. perfringens.
  • Tetanus: Early symptoms include progressive tissue infection, weakness, and stiffness followed by muscle spasms and seizures.
  • C. perfringens: This can result in necrotizing disease with early symptoms of skin discoloration and fluid-filled blisters. Systemic symptoms (hypotension) follow.
• Leprosy: Caused by Mycobacterium leprae; characterized by skin lesions and nerve damage. Two types exist: tuberculoid (less severe, less contagious) and lepromatous (more severe and more contagious).
• Other: Scabies, head lice, insect bites, and insect stings.

Mouth Conditions

• Cold sores: Caused by Herpes simplex virus type 1, presenting as recurrent sores (with a rash), or painful lesions.
• Mouth Ulcers: Inflammatory damage to the oral epithelium, often triggered by physical injury, nutritional deficiencies, or stress.
• Oral Candidiasis: Fungal infection caused by Candida albicans, often common in infants and older adults with compromised immune systems. Risk factors include: Immunocompromised, reduced saliva, uncontrolled diabetes, regular inhaled corticosteroid therapy.
• Angular cheilitis: A condition affecting the corners of the mouth, marked by inflammation, often triggered by skin conditions, nutritional deficiencies, or other chronic conditions

Ear and Eye Infections

• Conjunctivitis: Inflammation of the conjunctiva. Three types of bacterial, viral and allergic infections.
• Dry Eye: Deficiency or dysfunction of the tear film.
• Otitis Externa: Inflammation of the outer ear canal. A common cause is moisture.
• Ear Wax Implications: Build-up of ear wax can cause hearing loss and be associated with other medical conditions like systemic illness or hearing aids.

GI Conditions

• Inflammatory Bowel Disease: Two types, Ulcerative Colitis (affects only colon) and Crohn's disease (affects any part of GI tract). Characterized by inflammation and ulceration.
• Coeliac Disease: An inflammatory disease caused by gluten, triggering an immune response in the small intestine and causing damage to the villi.
• Gastric Acid Secretion Process: The phases of gastric acid secretion are triggered by stimuli in the cephalic, gastric and intestinal phases.
• Peptic Ulcer Disease: An erosion of the lining of the stomach or duodenum caused by injury, usually by H. Pylori.
• GORD: Chronic condition caused by reflux of gastric acid upward into the oesophagus.
• Zollinger-Ellison Syndrome: Pancreatic tumor producing excessive gastric acid resulting in frequent peptic ulcers
• Haemorrhoids: Occur when vascular-rich connective tissue becomes engorged or swollen, often occurring in the rectum or anus, usually (but not always) leading to pain and swelling or bleeding.
• Threadworms: Small, thin worms in the bowel resulting from ingestion and self-infection. Common in people with inadequate hygiene and can cause itching.

Viral Hepatitis; Food Poisoning; GI Infections

• Types of viral hepatitis with their causes and transmission.
• Causes of and types of food poisoning and other GI Infections.

MSK Conditions

• Osteoarthritis: A chronic joint disease, most common in elderly adults (over 55). Risk factors include age, obesity, and injury.
• Rheumatoid Arthritis: A chronic inflammatory disorder that leads to joint destruction and deformity. It is more common in women, and associated with genetic factors, environmental factors and chance events.
• Gout: Caused by deposition of monosodium urate crystals in the joints. Risk is higher in men than women.
• Pseudo Gout: Caused by the deposition of calcium pyrophosphate crystals in the joints. More prevalent in women.

Pain

• Pain Description categories: Acute, chronic, cancer, and phantom pain. Types include nociceptive and neuropathic pain, which have subtypes.

Other Specific Conditions

• Osteomyelitis (bone infection)
• Septic arthritis (joint infection)
• Reactive arthritis (arthritis resulting from an infection elsewhere in the body)
• Osteoporosis (bone loss)

Test your knowledge on various medical conditions such as allergic conjunctivitis, dry eye, and otitis externa. This quiz also covers important aspects of inflammatory bowel disease and food poisoning. Assess your understanding of pathophysiology and immune responses in these conditions.