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What is the virus responsible for primary Chickenpox (Varicella)?

Varicella Zoster Virus.

What condition causes the reactivation of Varicella Zoster?

Herpes Zoster (Shingles).

Where in the body is the Varicella Zoster virus found?

Trigeminal ganglion.

What are the clinical symptoms of primary Varicella (Chickenpox)?

A fever lasting for 24 hours; A rash resembling dew drops on a rose petal that evolves from macules to papules to vesicles.

What symptoms are associated with shingles (Herpes Zoster)?

Localized pain in the dermatome affected; A rash with vesicles that do not cross the midline.

What is a notable symptom of shingles when affecting the ophthalmic or otic regions?

Ramsay Hunt Syndrome, which impacts both the trigeminal and facial nerves.

What methods are used to diagnose Varicella?

Tzanck smear; Observation of dendritic lesions during slit lamp examination.

What treatment options are available for unvaccinated or immunocompromised individuals with Varicella?

Administration of antiviral medications, such as acyclovir.

What does erythema multiforme typically look like?

It presents as red, layered lesions featuring a central red blister or macule, with a surrounding area of pallor and an outer erythematous ring.

What is a significant physical examination finding in erythema multiforme?

The Nikolsky sign is negative (the skin does not easily separate); the lesions do not cause itching, and they blanch when pressed.

What treatments are available for erythema multiforme?

Acyclovir is used for viral causes, and topical antibiotics may be prescribed for any secondary infections.

What is the underlying mechanism of Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)?

These conditions involve necrosis of the epidermis.

How are SJS and TEN graded based on the affected body surface area (BSA)?

Grade 1: Less than 10% BSA; Grade 2: 10-30% BSA; Grade 3: More than 30% BSA.

What symptoms characterize Stevens-Johnson Syndrome (SJS)?

Fever, stinging sensation in the eyes, flat target or purpuric macules with a central vesicle on the trunk, and mucosal lesions including bullae and ulceration.

What symptoms are associated with Toxic Epidermal Necrolysis (TEN)?

Presence of large blisters, a painful erythematous base, and significant involvement of body surface area.

What physical examination sign is observed in TEN?

The Nikolsky sign is positive (skin separates with gentle pressure).

How is Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis managed?

Severe cases may require steroid treatment and admission to a burn unit.

What is cellulitis?

Inflammation of the dermis and subcutaneous tissue.

What are the most common pathogens that cause cellulitis?

Group A Streptococcus (GAS) and Staphylococcus aureus.

What are the symptoms of cellulitis?

Erythema, swelling, warmth, and tenderness.

What is the treatment for cellulitis caused by GAS or Staphylococcus aureus?

Oral antibiotics: Cephalexin or Dicloxacillin; Intravenous antibiotics: Cefazolin.

What is the treatment for cellulitis caused by a cat or dog bite?

Augmentin.

What is the treatment for MRSA cellulitis?

Oral antibiotics: Bactrim, Doxycycline, Clindamycin; Intravenous antibiotics: Vancomycin.

What are the two types of cellulitis?

Non-purulent (caused by GAS) and Purulent (caused by MRSA).

What are the characteristics of non-purulent cellulitis?

No abscess or drainage; Systemic symptoms may include fever, erythema, edema, and tenderness to palpation.

What are the characteristics of purulent cellulitis?

Abscess with necrotic lesions; May present with folliculitis, furunculosis, or carbuncle.

How do you treat purulent cellulitis with abscesses?

Community-acquired MRSA: Bactrim, Doxycycline, Rifampin, Clindamycin; Hospital-acquired MRSA: Vancomycin, Linezolid; Administer Tetanus prophylaxis for open wounds.

What is the treatment for open wounds at risk for tetanus?

Tetanus prophylaxis if the wound is contaminated or the patient's immunization status is not current.

What is the treatment for heat cramps?

Electrolyte and salt solution.

What are the symptoms of heat exhaustion?

Hypotension (HoTN), nausea (N), vomiting (V), diarrhea (D), and no CNS involvement.

What is the treatment for heat exhaustion?

Cooling measures and fluids (electrolyte-rich).

What are the symptoms of heat stroke?

Hyperthermia and CNS dysfunction (e.g., confusion, seizures, coma).

What is the treatment for heat stroke?

Immediate cooling (ice, cold water immersion), IV fluids, and management of organ dysfunction.

What are the stages of trench foot?

Stage 1: Numbness, redness; Stage 2: Swelling, pale skin; Stage 3: Gangrene; Stage 4: Dead tissue.

What is the treatment for trench foot?

Do NOT rewarm immediately, Tetanus vaccination (Tdap), TCA + Gabapentin for pain, air drying, fluid management, and possible surgery.

What are the symptoms of chilblains?

Inflammation of toes/fingers, erythematous lesions, burning, tenderness, and pain.

What is the treatment for chilblains?

Remove from cold, stop smoking, topical steroids, and Nifedipine.

What are the stages of frostbite?

Stage 1: Redness, swelling; Stage 2: Blisters, numbness; Stage 3: Hemorrhage; Stage 4: Muscle or tissue necrosis.

What is the treatment for frostbite?

Pain management with morphine, NSAIDs for inflammation, Tetanus vaccination (Tdap), and do NOT dry warm the affected area.

What is the treatment for hypothermia?

Rewarming (passive or active), IV fluids (warmed), monitoring core temperature, and active warming if severe.

Where is the Brown Recluse spider most commonly found?

Southwestern and Midwestern United States.

What are the local effects of a Brown Recluse spider bite?

Burning and erythema for 3-4 hours; blanching of the affected area due to vasoconstriction; an erythematous margin around the ischemic center (red halo) for 24-72 hours; formation of a hemorrhagic bulla leading to eschar; 10% may develop skin necrosis.

What is the treatment for a Brown Recluse spider bite?

Local wound care: Clean with soap and water, apply cold packs, elevate the area; Pain control: NSAIDs, opioids for severe pain; Tetanus prophylaxis if needed; Most bites heal spontaneously within days to weeks.

How can you identify a Black Widow Spider?

A distinctive red hourglass shape on the underside of the abdomen.

What are the local and systemic effects of a Black Widow spider bite?

Local symptoms include pain at the bite site. Systemic symptoms can occur within 30 minutes to 2 hours and include muscle pain (the most prominent feature), muscle spasms, and rigidity.

What is the treatment for a Black Widow spider bite?

For mild cases, wound care involves cleaning with soap and water along with pain control using NSAIDs or opioids. For moderate to severe cases, muscle relaxants like benzodiazepines or methocarbamol may be used. Antivenom is reserved for patients who do not respond to the above treatments.

What are the characteristics of Superficial (1st degree) burns?

Affects only the epidermis; appears red, dry, and sunburn-like; painful to touch; heals in 3-6 days with no scarring; example: sunburn.

What are the characteristics of Superficial Partial-thickness (2nd degree) burns?

Affects the epidermis and superficial dermis (papillary layer); appears moist, red, weeping with blisters; painful to touch, air, and temperature changes; heals in 7-21 days with no scarring or mild pigment changes; example: blistering burn.

What are the characteristics of Deep Partial-thickness (2nd degree) burns?

Affects the epidermis and deeper dermis (reticular layer); appears mottled, waxy, cheesy white to red with easily unroofed blisters; painful only to pressure, some areas may be insensitive; heals in 2-9 weeks, potential for hypertrophic scarring; example: severe scald burns or contact burns.

What are the characteristics of Full Thickness (3rd degree) burns?

Affects the epidermis, dermis, and subcutaneous tissue; appears waxy white, charred, or leathery, dry and inelastic with no blisters; sensation limited to deep pressure; cannot heal without surgical intervention, severe scarring and contractures; example: severe electrical burns, prolonged exposure to flame.

What are the characteristics of Deep Injury (4th degree) burns?

Affects the epidermis, dermis, subcutaneous tissue, and deeper structures such as muscles, fat, fascia, and bones; appears black, charred, or dull, may have necrotic tissue; minimal sensation due to nerve destruction; life- and limb-threatening, requires amputation or reconstructive surgery; example: burns from prolonged contact with flames or electrical injuries.

What are the different types of burns and their classification?

• Superficial (1st degree): Affects the epidermis; appears as a sunburn (dry, red); painful; heals in 3-6 days with no scarring.

• Superficial partial-thickness (2nd degree): Impacts the epidermis and superficial dermis; appears moist and weeping; painful to touch; heals in 7-21 days with no scarring.

• Deep partial-thickness (2nd degree): Involves the epidermis and deeper dermis; appears mottled, cheesy white to red; painful only to pressure; potential for hypertrophic scarring; heals in 2-9 weeks.

• Full thickness (3rd degree): Goes through the epidermis, dermis, and subcutaneous tissue; appears waxy white to charred; no sensation; heals with surgical intervention; significant scarring.

• Deeper injury (4th degree): Affects all layers including muscles and bones; appears black or charred; minimal sensation; life-threatening.

What are the criteria for minor burns?

• Partial-thickness burns: <10% TBSA for ages 10-50, <5% TBSA for ages <10 or >50.

• Full-thickness burns: <2% TBSA in any patient.

• Other criteria: Isolated injury without signs of inhalation/high-voltage injury; no involvement of face, hands, feet, genitalia, or major joints.

When should a burn patient be referred to a burn center?

• Partial-thickness burns >10% TBSA

• Third-degree burns regardless of age

• Burns on face, hands, feet, genitalia, or major joints

• Electrical burns (including lightning)

• Chemical burns

• Inhalation injury

• Burns in patients with complicating medical conditions.

How do you estimate the total body surface area (TBSA) for burns?

• Rule of 9s:

  • Head/neck = 9%

  • Each arm = 9%, each leg = 18%

  • Anterior trunk = 18%, posterior trunk = 18%

  • Genitalia = 1%

• Palmar Method: Patient’s palm estimates 1% TBSA.

What is the Parkland formula for fluid resuscitation in burn patients?

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  Parkland formula:4 mL × %TBSA × weight (kg)

• Administer the first half of the calculated volume in the first 8 hours and the remaining half over the next 16 hours; typically use Lactated Ringer’s for fluid replacement.

What are the immediate measures for managing burn patients?

• Airway management: Intubate if inhalation injury is suspected or with >30-40% TBSA burns.

• Vascular access: Establish early intravenous access.

• Fluid resuscitation: Use Parkland formula for burns >15% TBSA.

• Burn care: Remove burnt clothing and cool burns with water or saline-soaked gauze (never use ice); maintain body temperature ≥95°F (35°C).

What are the treatment options for burn wounds?

• Superficial & superficial partial-thickness burns:

  • Irrigation, topical moisturizers (e.g., calamine lotion), and topical antibiotics (e.g., bacitracin, neomycin, polymyxin B).

• Deep partial-thickness, 3rd/4th-degree burns:

  • Early debridement, possible escharotomy/fasciotomy, skin grafts, and topical antibiotics like silver sulfadiazine or mafenide acetate.

What is the causative agent of rabies?

Rabies is caused by the rabies virus, a rhabdovirus.

How is rabies transmitted?

Rabies is transmitted through saliva of infected animals via bites, scratches, or exposure to open wounds or mucous membranes.

What animals are commonly associated with rabies transmission?

Common reservoirs include bats, foxes, raccoons, skunks, and dogs (especially in regions where vaccination is not widespread).

What is the incubation period for rabies?

The incubation period for rabies is usually 1-3 months, but it can range from 1 week to 1 year depending on the bite location and virus strain.

What are the early symptoms of rabies infection?

Early symptoms are non-specific and may include fever, malaise, headache, fatigue, and pain or tingling at the site of the bite (paresthesia).

What neurological symptoms appear as rabies progresses?

As the disease progresses, symptoms include agitation, confusion, hydrophobia (fear of water), aerophobia (fear of drafts of air), severe pharyngeal spasms, hypersalivation, seizures, and paralysis.

What are the final stages of rabies infection?

In the final stages, coma develops, followed by cardiac and respiratory failure due to medullary dysfunction. Death typically occurs within 2-10 days after onset of symptoms, usually from respiratory failure.

How is rabies diagnosed?

Diagnosis is clinical, with laboratory tests including direct fluorescent antibody (DFA) test on brain tissue (post-mortem), RT-PCR for rabies virus RNA, rabies antibody titers in serum or CSF, and skin biopsy may show the rabies virus in the nervous tissue.

What is the treatment for rabies after exposure?

Post-exposure prophylaxis (PEP) includes rabies immune globulin (RIG) at the site of exposure and a rabies vaccine (4 doses over 14 days). PEP is recommended for all individuals with potential rabies exposure.

What is the prognosis for someone who develops clinical rabies?

Once clinical symptoms appear, rabies is almost always fatal with a near 100% mortality rate.

Can rabies be prevented?

Rabies can be prevented by vaccination of domestic animals, pre-exposure prophylaxis for high-risk individuals, and avoidance of animal bites.