D118 Unit 4 Study Guide

Unit 4: Acute Illnesses: Urinary, Renal, Dermatologic, Musculoskeletal & Infectious Diseases

Managing Acute Urinary Tract and Renal Disorders

Acute kidney and urinary tract disorders frequently affect both pediatric and adult populations. One notable condition is glomerulonephritis, an acute inflammatory process of the kidney often triggered by a prior Streptococcus bacterial infection. Symptoms typically appear one to one and a half weeks after the initial infection. Another common disorder is nephrolithiasis, characterized by the formation of kidney stones that may obstruct urine flow and cause intense pain.

Urinary Tract Infections (UTIs) can involve any part of the urinary system—including kidneys, ureters, bladder, or urethra. A related condition, urethritis, specifically refers to inflammation of the urethra and can result from mechanical irritation, chemical exposure, viruses, or bacterial infection. Nongonococcal urethritis (NGU), often due to Chlamydia trachomatis, is the most prevalent type.

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What are the clinical manifestations, diagnostic criteria, and treatments for urinary tract infections?

Condition	Clinical Manifestations	Diagnostic Criteria	Treatment
UTI	Uncomplicated: Symptoms include urinary frequency, urgency, painful urination (dysuria), suprapubic pain, foul-smelling urine, and sometimes hematuria. Complicated: Fever, chills, flank pain, costovertebral angle tenderness, nausea, vomiting.	Uncomplicated: Urinalysis and urine culture confirm diagnosis. Sterile pyuria indicated by positive urinalysis with negative cultures. Complicated: Imaging (renal ultrasound) detects abnormalities like stones or hydronephrosis. Persistent infections require urology referral.	Increase fluid intake. For nonpregnant women, first-line antibiotics include nitrofurantoin or trimethoprim-sulfamethoxazole if resistance is low; alternatives include fosfomycin, fluoroquinolones, cephalosporins. Pregnant women are treated with cephalexin or amoxicillin. Men receive similar antibiotic regimens adjusted by susceptibility.
Urethritis	Men may report dysuria, increased urinary frequency, urethral discharge, and itching. Women may experience frequency, nocturia, dysuria, itching, fever, hematuria, discharge, pelvic discomfort, or back pain.	Diagnosis involves urinalysis, Gram stain, cultures (especially in young men), wet mounts, and specific tests for gonorrhea and chlamydia.	First-line treatment includes a single dose of azithromycin or doxycycline for seven days. Erythromycin and fluoroquinolones are alternatives.
Pyelonephritis	Chills, high fever (>100°F), frequent painful urination, flank and groin pain, nausea, vomiting, dysuria, urgency.	Urinalysis, urine and blood cultures, complete blood count (CBC), and imaging studies such as CT or ultrasound.	Antibiotics for at least two weeks; surgical intervention if urinary obstruction occurs.
Nephrolithiasis	Sudden severe flank or abdominal pain indicating obstruction; intermittent pain suggests partial obstruction, constant pain indicates complete blockage. Other symptoms: nausea, vomiting, hematuria, fever, tenderness at costovertebral angle.	Urinalysis and culture assess pH, bacteria, crystals, blood. Labs include CBC, metabolic panel, parathyroid hormone, vitamin D levels, and 24-hour urine analysis. Stone analysis is crucial.	Hydration, pain management, and facilitating stone passage. Specific treatments depend on stone type (e.g., thiazides for calcium stones, urine alkalinization for uric acid stones). Urgent referral for severe cases.

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Managing Acute Skin and Nail Disorders

Several acute skin and nail disorders require prompt recognition and treatment. Intertrigo is a superficial inflammation resulting from persistent skin-to-skin contact in warm, moist, and friction-prone areas, often leading to bacterial or fungal overgrowth. Impetigo mainly affects infants and young children and manifests as either nonbullous or bullous lesions, frequently caused by Staphylococcus aureus. Cellulitis presents with localized redness, swelling, warmth, pain, and systemic symptoms, occasionally producing pus.

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What are the clinical manifestations, diagnostic criteria, and treatments for bacterial skin infections?

Infection	Clinical Manifestations	Diagnostic Criteria	Treatment
Impetigo	Honey-colored crusts, translucent vesicles or pustules on erythematous, moist bases.	Diagnosis primarily clinical; cultures and Gram stain for complicated or MRSA cases. Urinalysis in children (2-4 years) to exclude nephritis.	Topical mupirocin ointment; oral antibiotics like dicloxacillin or cephalexin for extensive disease; daily antimicrobial washing.
Cellulitis	Erythema, swelling, warmth, pain, sometimes with bullae, abscess, or necrosis; systemic signs such as fever.	CBC with differential, renal function tests, cultures of pus if present, blood cultures, imaging as needed.	Oral antibiotics and NSAIDs; intravenous antibiotics for severe cases (targeting MRSA); incision and drainage for abscesses.
Intertrigo	Redness, peripheral scaling, macerated plaques with itching, burning, sometimes odor or discharge.	Clinical diagnosis; KOH prep, Gram stain, and Wood lamp for erythrasma identification.	Topical antifungal or antibacterial agents based on causative organism.
Furuncle/Carbuncle	Tender, warm nodules often with fever and malaise.	Clinical examination.	Incision and drainage; systemic antibiotics if systemic symptoms present.

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Viral Skin Infections

Warts caused by human papillomavirus (HPV) present as small, firm, skin-colored papules, commonly on the hands and feet. Plantar warts are thicker and rougher on the soles. Diagnosis is clinical, often confirmed by identifying pinpoint capillaries during lesion debridement. Treatment options range from topical agents to cryotherapy, laser ablation, or surgical excision.

Other common fungal infections include tinea corporis (ringworm), which appears as red, ring-shaped plaques with raised borders and central clearing. Tinea versicolor produces hypo- or hyperpigmented scaly patches mainly on the trunk and arms, typically asymptomatic.

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What are the clinical features, diagnosis, and treatments for viral and fungal skin infections?

Infection	Clinical Presentation	Diagnostic Criteria	Treatment
Warts (HPV)	Small, firm, skin-colored papules; plantar warts are thickened and rough on soles.	Clinical diagnosis; visualization of pinpoint capillaries during debridement.	Topical agents, cryotherapy, laser ablation, or surgical excision.
Dermatophyte Tinea	Annular, scaly plaques with central clearing, possible pustules, itching or burning.	KOH microscopy and Wood lamp examination.	Topical antifungals for skin; oral antifungals for scalp or nails.
Tinea Versicolor	Hypo- or hyperpigmented scaly patches on trunk and neck.	KOH prep, Wood lamp, skin cultures; liver function tests if systemic treatment planned.	Topical antifungals first; systemic antifungals for widespread or resistant cases.
Candidiasis	White or gray plaques on mucous membranes (oral thrush); vaginal itching and discharge.	KOH prep and cultures; biopsy if unclear.	Oral nystatin or fluconazole for oral infections; topical or systemic antifungals for other sites.

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Dermatological Office Procedures

Cryosurgery uses liquid nitrogen to freeze and destroy lesions but is contraindicated in patients with cold intolerance or hematologic conditions, and may cause pigment changes, particularly in darker skin types. Protective measures are necessary near sensitive areas.

Electrocautery uses electric currents to cut or cauterize tissue, useful for vascular lesions and some skin cancers. Curettage involves scraping lesions with a curet, commonly for seborrheic keratoses, warts, molluscum, and certain skin cancers, usually under local anesthesia.

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What are the indications, contraindications, precautions, and preparation steps in dermatological procedures?

Procedure	Indications	Contraindications and Precautions	Preparation and Notes
Cryosurgery	Removal of benign and premalignant lesions	Cold intolerance, hematologic disorders; pigment alteration risk in dark skin. Protect sensitive areas.	Use protective barriers; educate patient on post-care.
Electrocautery	Vascular lesions, some skin cancers	Avoid in patients with pacemakers or bleeding disorders without consultation.	Local anesthesia often required; sterile technique.
Curettage	Seborrheic keratoses, warts, molluscum, skin cancers	Infection risk; avoid over-aggressive scraping to minimize scarring.	Local anesthesia; sterile environment; post-procedure wound care.

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Parasitic Infestations

Scabies is characterized by intensely pruritic small papules and serpiginous burrows in classic locations. The crusted form affects immunocompromised individuals and is highly contagious. Treatment includes topical permethrin 5% cream or oral ivermectin.

Pediculosis capitis (head lice) causes scalp itching, with visible lice and nits near the neck and behind the ears. Treatment involves topical permethrin or prescription medications suitable for children.

Bed bug infestations result in itchy wheals and blood stains on bedding. Management focuses on eliminating infestation and symptomatic relief.

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What are the clinical signs and treatment options for common parasitic skin infestations?

Infestation	Clinical Signs	Treatment
Scabies	Intense itching, papules, serpiginous burrows.	Topical permethrin 5% cream or oral ivermectin.
Pediculosis	Scalp itching, visible lice and nits near neck and ears.	Permethrin-based shampoos or prescription treatments.
Bed Bugs	Itchy wheals, blood stains on bedding.	Eradication of infestation; symptomatic relief with antihistamines.

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Adnexal Diseases (Hair, Sweat Glands, Nails)

Common adnexal disorders include acne vulgaris, rosacea, and hyperhidrosis. Acne is marked by comedones, papules, pustules, or nodules, typically on the face, neck, and upper trunk. Treatment aims at normalizing keratinization, reducing sebum production, and controlling inflammation with topical retinoids, antibiotics, or hormonal therapies.

Rosacea manifests as facial flushing, erythema, papules, pustules, telangiectasia, and sometimes ocular involvement. It is managed with topical metronidazole, oral antibiotics, and lifestyle modifications.

Hyperhidrosis involves excessive localized sweating that impacts quality of life. Treatments include topical aluminum chloride, oral anticholinergics, and botulinum toxin injections.

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Minor Burns

Burns are categorized by depth:

• First-degree burns affect only the epidermis, presenting with redness, glossiness, and pain (e.g., sunburn).
• Second-degree burns involve the dermis, causing blistering and severe pain.
• Third-degree burns extend into subcutaneous tissue with a dry, white or charred appearance and possible nerve damage leading to insensitivity.

Examination requires assessment of airway, breathing, circulation, burn depth, total body surface area (TBSA), and associated injuries. Circumferential burns warrant special attention due to the risk of vascular compromise.

Management includes topical antimicrobials such as silver sulfadiazine, non-adherent dressings, analgesics, and tetanus prophylaxis.

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Dermatitis and Other Skin Conditions

Dermatitis Type	Clinical Features	Physical Exam Findings	Management
Eczematous (Atopic)	Itchy, red, dry patches, often with scaling and lichenification.	Poorly defined lesions with crusting, oozing, thickened skin.	Patient education, trigger avoidance, antihistamines, topical steroids, emollients.
Contact Dermatitis	Itching, burning, redness, swelling with clear borders; vesicular or scaly lesions.	Localized inflammation, sometimes linear patterns (e.g., poison ivy).	Avoid irritants/allergens; topical corticosteroids; symptomatic treatment.
Seborrheic Dermatitis	Red, flaky patches on scalp, face, ears, trunk.	Yellowish/white greasy scales; cradle cap in infants.	Antifungal shampoos, topical steroids, keratolytic agents.
Cutaneous Drug Reactions	Ranges from mild rash to severe (e.g., Stevens-Johnson Syndrome).	Erythema, pustules, bullae, systemic symptoms.	Immediate cessation of offending drug, supportive care, corticosteroids, hospitalization if severe.
Stasis Dermatitis	Skin discoloration, itching, ulcer formation on lower limbs.	Edema, varicosities, hyperpigmentation.	Leg elevation, compression stockings, corticosteroids, surgical options if needed.
Urticaria (Hives)	Transient, raised, itchy wheals anywhere on body.	Wheals of varying size; no scarring.	Avoid triggers, antihistamines, epinephrine for anaphylaxis.

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Clinical Presentation, Physical Examination, and Management of Corns and Calluses

Aspect	Details
Clinical Manifestation	Corns are painful, localized lesions typically on toes or dorsal foot surfaces; calluses are thickened skin areas that are usually painless.
Examination	Corns appear as tender, red lesions often associated with foot deformities (e.g., hammertoes); calluses present as diffuse thickening that can mask deeper problems.
Management	Prevention through proper footwear, pressure-relieving pads, regular debridement, moisture control, orthotics for deformities, and surgery if needed. Diabetic or vascular disease patients require close monitoring.

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Nail Disorders

Herpetic whitlow manifests as painful vesicles on the distal finger, often accompanied by tingling or numbness. Examination includes assessment of nails, lymph nodes, and possible genital herpes if symptoms suggest systemic involvement. Management includes drainage when necessary, cold compresses, and preventing viral spread.

Paronychial infections present with pain, swelling, and sometimes pus around the nail fold. Tenderness and discoloration (e.g., greenish tint from Pseudomonas) are common. Treatment involves warm soaks, drainage of abscess if present, and topical antibiotics.

Onychomycosis involves thickened, brittle, discolored nails. Oral antifungals are preferred for treatment, with topical agents as adjuncts.

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Musculoskeletal Injuries and Illnesses

Condition	Clinical Manifestation	Examination Findings	Management
Sprains and Strains	Pain, swelling, muscle spasm (strain), bruising (sprain)	Deformity, limited range of motion (ROM), guarding	Rest, Ice, Compression, Elevation (RICE), splinting, NSAIDs, physical therapy
Fractures	Pain, swelling, deformity, discoloration	Neurovascular status, palpable deformity	Immobilization, surgery if needed, pain control
Bursitis	Swelling, warmth, erythema, pain	Localized tenderness and swelling	NSAIDs, antibiotics if infected, aspiration, corticosteroids
Carpal Tunnel / De Quervain’s Tenosynovitis	Pain near thumb base, radiating along tendon	Tenderness, reduced ROM	Splinting, NSAIDs, physical therapy, corticosteroids
Sciatica	Radiating leg pain with limited motion	Neurological deficits	NSAIDs, rest, physical therapy
Joint Pain (Hand/Wrist/Elbow/Shoulder)	Localized pain, numbness, weakness	ROM, grip strength, neurological testing	NSAIDs, physical therapy, injections, surgery if indicated
Neck and Low Back Pain	Pain with limited movement, possible neurological signs	Posture, gait, ROM, neurological exam	NSAIDs, rest, physical therapy, imaging if necessary

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Infectious Diseases: Clinical Presentation, Examination, and Management

Disease	Clinical Manifestation	Examination Features	Management
Lymphadenopathy	Swollen, painful, or firm lymph nodes	Size, location, tenderness, symmetry	Treat underlying cause; biopsy if malignancy suspected
Fever (Pyrexia)	Elevated body temperature as immune response	Variable depending on infection	Supportive care, antipyretics, treat cause
Infectious Mononucleosis	Fever, sore throat, lymphadenopathy	Cervical lymphadenopathy, splenomegaly	Supportive care; steroids if severe; avoid antibiotics to prevent rash
Tuberculosis	Chronic cough, weight loss, night sweats, fever	Rales, pleural effusion, lymphadenopathy	Prolonged multidrug antibiotic therapy
Lyme Disease	Expanding circular rash (erythema migrans), flu-like symptoms, joint pain	Rash and regional lymphadenopathy	Early oral antibiotics, supportive care
Rocky Mountain Spotted Fever	Fever, rash, headache	Petechial rash, systemic signs	Prompt antibiotic therapy
Zika Virus	Fever, rash, conjunctivitis	Possible neurological symptoms	Supportive care, mosquito control
Influenza	Fever, chills, malaise, cough	Usually normal chest exam	Symptomatic treatment, antivirals within 48 hours
Mosquito-Borne Illnesses	Weakness,

paralysis, rash, conjunctivitis | Rash, jaundice, lymphadenopathy | Supportive care, vector control, public health measures |

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Summary Table: Infectious Disease Management

Disease Category	Treatment Highlights
Bacterial infections	Antibiotics tailored to specific pathogens
Viral infections	Supportive care and symptom management
Tick-borne diseases	Early antibiotic treatment (e.g., doxycycline)
Mosquito-borne illnesses	Vector control and symptomatic management
Tuberculosis	Extended multi-drug antibiotic therapy

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References

Bolognia, J. L., Schaffer, J. V., & Cerroni, L. (2017). Dermatology (4th ed.). Elsevier.

Centers for Disease Control and Prevention. (2023). Lyme Disease. Retrieved from https://www.cdc.gov/lyme/index.html

Fitzpatrick, T. B., Johnson, R. A., & Wolff, K. (2019). Fitzpatrick’s Dermatology in General Medicine (9th ed.). McGraw-Hill.

Habif, T. P. (2015). Clinical Dermatology (6th ed.). Elsevier.

James, W. D., Berger, T. G., & Elston, D. M. (2015). Andrews’ Diseases of the Skin: Clinical Dermatology (12th ed.). Elsevier.

James, W. D., Berger, T. G., & Elston, D. M. (2018). Andrews’ Diseases of the Skin: Clinical Dermatology (13th ed.). Elsevier.

Longo, D. L., Fauci, A. S., Kasper, D. L., Hauser, S. L., Jameson, J. L., & Loscalzo, J. (2018). Harrison’s Principles of Internal Medicine (20th ed.). McGraw-Hill Education.

McCance, K. L., & Huether, S. E. (2021). Pathophysiology: The Biologic Basis for Disease in Adults and Children (8th ed.). Elsevier.

Tintinalli, J. E., et al. (2020). Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (9th ed.). McGraw-Hill.

UpToDate. (2023). Management of common skin infections and inflammatory skin disorders. Retrieved from https://www.uptodate.com