Introduction

Enthesitis is the painful inflammation of an enthesis, the site where ligaments or tendons attach to bone. Common in spondyloarthritis (e.g., psoriatic arthritis), it typically causes pain, stiffness, and tenderness, often in the heels, elbows, or hips. Treatment includes NSAIDs, biologics, rest, and physical therapy to manage symptoms and prevent potential joint damage. 

Symptoms of Enthesitis

• Pain: Often described as severe or burning, specifically at tendon insertion sites, such as the Achilles tendon or bottom of the foot.
• Stiffness: Increased difficulty moving the affected joint.
• Tenderness: Sensitivity to touch.
• Swelling: While not always present, swelling can occur in the soft tissue surrounding the site.
• Impact on Mobility: Chronic cases can limit mobility and cause damage to adjacent bone and joints.

Causes and Risk Factors

• Inflammatory Arthritis: Most frequently associated with psoriatic arthritis (PsA), ankylosing spondylitis (AS), and other forms of spondyloarthritis (SpA).
• Physical Stress/Overuse: Repeated physical activity causing strain at the attachment site.
• Immune System Dysfunction: Pro-inflammatory cytokine activity (specifically IL-17 and TNF-) is a major contributor to this inflammatory cascade.

Treatment Approaches

• Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) are the first line of treatment. For more chronic cases, biologics targeting TNF or IL-17 are often used.
• Physical Interventions: Rest, immobilization, and gentle stretching.
• Injections: Local corticosteroid injections, though used with caution near tendons.
• Lifestyle Changes: Maintaining a healthy weight to reduce pressure on joints. CreakyJoints

Common Sites

Enthesitis can occur throughout the body, with more than 100 potential locations. Common sites include:

• Achilles tendon (heel)
• Plantar fascia (bottom of the foot)
• Elbows (epicondylitis)
• Hips
• Patellar tendon (knee)

JIA = Juvenile Idiopathic Arthritis
A chronic inflammatory arthritis of unknown cause beginning before age 16 and lasting ≥ 6 weeks, after exclusion of other causes.

✅ Definition (Juvenile Idiopathic Arthritis)

• Arthritis in ≥1 joint
• Onset < 16 years
• Duration ≥ 6 weeks
• Other causes excluded (infection, malignancy, trauma, connective tissue diseases)

🧬 ILAR Classification (Most used worldwide)

1️⃣ Oligoarticular JIA

Most common type (~50%)

Criteria

• ≤4 joints involved in first 6 months

Subtypes

• Persistent: remains ≤4 joints
• Extended: becomes >4 joints after 6 months

Features

• Large joints (knee most common)
• Asymmetric
• ANA positive common
• Risk of uveitis

2️⃣ Polyarticular JIA (RF negative)

Criteria

• ≥5 joints in first 6 months
• RF negative

Features

• Small joints of hands/feet
• Symmetrical
• Chronic course

3️⃣ Polyarticular JIA (RF positive)

Criteria

• ≥5 joints
• RF positive (≥2 tests, 3 months apart)

Features

• Similar to adult rheumatoid arthritis
• Severe, erosive disease
• Adolescents (girls common)

4️⃣ Systemic JIA (Still disease)

Criteria

• Arthritis with or preceded by fever ≥2 weeks
• Daily (quotidian) fever for ≥3 days
  PLUS ≥1:
• Evanescent salmon-pink rash
• Hepatosplenomegaly
• Lymphadenopathy
• Serositis

Features

• High ferritin
• Risk of MAS (macrophage activation syndrome)

5️⃣ Enthesitis-related Arthritis (ERA)

Criteria
Arthritis + enthesitis
OR arthritis/enthesitis + ≥2:

• Sacroiliac tenderness/inflammatory back pain
• HLA-B27 positive
• Male >6 years
• Acute anterior uveitis
• Family history of spondyloarthropathy

Features

• Lower limb arthritis
• May progress to ankylosing spondylitis

6️⃣ Psoriatic Arthritis

Criteria
Arthritis + psoriasis
OR arthritis + ≥2:

• Dactylitis
• Nail pitting/onycholysis
• Psoriasis in first-degree relative

7️⃣ Undifferentiated JIA

• Does not fit above categories
  OR fits more than one category

🧪 Diagnostic Criteria & Workup

🔹 Clinical Diagnosis (Primary)

No single confirmatory test.

🔹 Essential Features

✔ Chronic joint swelling or limitation
✔ Morning stiffness
✔ Pain improves with activity
✔ Reduced range of motion

🔬 Laboratory Findings (Supportive)

🩻 Imaging

Early

• Ultrasound → synovitis, effusion

Later

• X-ray → joint space narrowing, erosions, growth abnormalities
• MRI → early synovitis & sacroiliitis

🚨 Important Diagnostic Exclusions

Before diagnosing JIA, rule out:

• Septic arthritis
• Tuberculosis
• Leukemia
• SLE
• Rheumatic fever
• Trauma
• Hemophilia

⚠️ Red Flags suggesting other diagnosis

• Severe bone pain at night → leukemia
• High fever with toxicity → infection
• Weight loss, pallor → malignancy
• Acute monoarthritis → septic arthritis

🧠 Exam Pearls (High Yield)

✔ Oligoarticular = most common
✔ Systemic JIA = quotidian fever + rash
✔ ANA+ girls → high uveitis risk
✔ RF+ polyarticular → resembles adult RA
✔ ERA → HLA-B27 boys, lower limb arthritis
✔ Screen for uveitis regularly even if asymptomatic

Newborn care is broadly classified into three levels based on the complexity of care, monitoring, and interventions required.

1. Level I – Basic Newborn Care (Well Newborn Nursery)

Definition

Care provided to healthy term newborns and stable late preterm infants who require only routine monitoring.

Babies managed

• Term newborns (≥37 weeks)
• Birth weight ≥2500 g
• Babies with no complications
• Stable late preterm (≥35 weeks)

Services provided

• Routine neonatal examination
• Thermal care
• Early breastfeeding support
• Cord care
• Monitoring:
  • Temperature
  • Feeding
  • Urination/stooling
• Immunization (BCG, OPV, Hep B depending on country policy)
• Screening tests
• Parent education

Procedures allowed

• Basic resuscitation
• Oxygen by hood
• IV fluids if needed briefly

Staffing

• Pediatrician or trained medical officer
• Nurses trained in newborn care

2. Level II – Special Care Newborn Unit (SCNU / Special Care Nursery)

Definition

Care for moderately ill newborns who require closer monitoring or short-term intensive support.

Babies managed

• Preterm infants ≥32 weeks
• Birth weight ≥1500 g
• Neonates recovering from severe illness
• Neonates needing short-term respiratory support

Indications

• Respiratory distress
• Neonatal jaundice requiring phototherapy
• Sepsis (suspected)
• Feeding difficulty
• Hypoglycemia
• Hypothermia
• Apnea of prematurity

Services provided

• Continuous monitoring
• Phototherapy
• IV fluids and medications
• Tube feeding
• Oxygen therapy
• CPAP (in many Level II units)
• Short-term mechanical ventilation (<24 hr)

Procedures

• Umbilical catheterization
• Lumbar puncture
• Exchange transfusion (in some units)

Staffing

• Pediatricians
• Neonatal nurses
• Access to laboratory and imaging

3. Level III – Neonatal Intensive Care Unit (NICU)

Definition

Provides comprehensive intensive care for very sick or extremely premature neonates.

Babies managed

• Gestational age <32 weeks
• Birth weight <1500 g (VLBW)
• Extremely low birth weight (<1000 g)
• Neonates requiring advanced respiratory support

Conditions managed

• Severe respiratory distress syndrome
• Birth asphyxia
• Persistent pulmonary hypertension
• Sepsis/septic shock
• Major congenital anomalies
• Surgical conditions
• Severe prematurity complications

Services provided

• Mechanical ventilation
• High frequency ventilation
• Surfactant therapy
• Total parenteral nutrition (TPN)
• Continuous cardiorespiratory monitoring
• Central lines
• Invasive procedures
• Advanced imaging
• Neonatal surgery (in Level III C)

Sub-classification (sometimes used)

• Level III A – mechanical ventilation
• Level III B – advanced ventilation + surgery
• Level III C – ECMO capable units

Staffing

• Neonatologist
• Pediatric intensivists
• Specialized neonatal nurses
• Respiratory therapists
• Full laboratory and imaging services

Simplified Summary Table

Alternative Public Health Classification (Used in Many Countries)

1. Home care
2. Community level care
3. Facility based newborn care
   • NBCC (Newborn Care Corner)
   • SNCU
   • NICU

✅ Exam Pearls (Pediatrics / Neonatology)

• Level I → routine care
• Level II → moderate illness, ≥32 weeks
• Level III → intensive care, <32 weeks
• VLBW infants (<1500 g) should be managed in Level III NICU

Definition

Pulsus paradoxus is an exaggerated fall in systolic blood pressure (>10 mmHg) during inspiration.

Normally, systolic BP falls slightly during inspiration (<10 mmHg).
When the drop is >10 mmHg, it is called pulsus paradoxus.

Despite the name “paradoxus”, the pulse does not actually disappear; it only becomes weaker or unpalpable during inspiration.

Normal Physiology

During inspiration:

• Intrathoracic pressure decreases
• Venous return to the right ventricle increases
• RV expands
• Interventricular septum shifts slightly toward the left ventricle
• LV filling decreases slightly
• Systolic BP falls by <10 mmHg

Mechanism of Pulsus Paradoxus

In certain conditions:

1. Excess RV filling or external compression
2. RV expansion pushes interventricular septum toward LV
3. LV filling markedly decreases
4. LV stroke volume falls
5. Systolic BP drops >10 mmHg during inspiration

Causes of Pulsus Paradoxus

Cardiac Causes

• Cardiac Tamponade (classic cause)
• Constrictive Pericarditis
• Large pericardial effusion

Respiratory Causes

• Severe Asthma
• Chronic Obstructive Pulmonary Disease exacerbation

Other Causes

• Tension Pneumothorax
• Massive pulmonary embolism
• Severe hypovolemia
• Upper airway obstruction

How to Measure Pulsus Paradoxus

Using a sphygmomanometer:

1. Inflate cuff above systolic pressure.
2. Slowly deflate.
3. Note two pressures:

• First pressure: Korotkoff sounds heard only during expiration
• Second pressure: Sounds heard throughout inspiration and expiration

Difference between the two = Pulsus paradoxus

Example:

• Expiration only = 120 mmHg
• Throughout respiration = 105 mmHg

Pulsus paradoxus = 15 mmHg

Clinical Significance

A pulsus paradoxus >10 mmHg suggests serious cardiopulmonary disease, especially:

• Cardiac tamponade
• Severe asthma attack

Reverse Pulsus Paradoxus

Reverse pulsus paradoxus is a rare cardiovascular finding in which systolic blood pressure increases during inspiration, opposite to the normal drop seen in typical pulsus paradoxus. It is most commonly associated with conditions that alter intrathoracic pressure dynamics or ventricular interaction, such as positive pressure ventilation, hypertrophic obstructive cardiomyopathy (HOCM), isovolumetric ventricular pacing, and sometimes aortic regurgitation.

The mechanism usually involves enhanced left ventricular filling or reduced afterload during inspiration, leading to a paradoxical rise in systolic pressure. Clinically, it is less frequently encountered than classic pulsus paradoxus and is often identified in intensive care settings where patients are mechanically ventilated. Recognition of reverse pulsus paradoxus is important because it can provide clues about underlying cardiac physiology and ventilatory influences rather than indicating conditions like cardiac tamponade, which are linked to the traditional form.

Quick Exam Definition

Pulsus paradoxus is an inspiratory fall in systolic blood pressure greater than 10 mmHg.

Pulsus paradoxus is demonstrated using a blood pressure cuff and stethoscope.

Step-by-Step Procedure

1. Position the Patient

• Patient should be lying supine or semi-recumbent
• Ask the patient to breathe normally

2. Inflate the BP Cuff

• Inflate the cuff 20–30 mmHg above systolic pressure

3. Slowly Deflate the Cuff

Deflate slowly at 2–3 mmHg per second while auscultating the brachial artery.

4. Identify the First Pressure

At first you will hear Korotkoff sounds only during expiration and they disappear during inspiration.

Record this pressure.

Example: 120 mmHg

Reason: During inspiration the systolic pressure falls below cuff pressure.

5. Continue Deflating

As the cuff pressure falls further, Korotkoff sounds will be heard throughout the respiratory cycle (during both inspiration and expiration).

Record this second pressure.

Example: 105 mmHg

6. Calculate Pulsus Paradoxus

Pulsus paradoxus=First pressure−Second pressure\text{Pulsus paradoxus} = \text{First pressure} – \text{Second pressure}Pulsus paradoxus=First pressure−Second pressure

Example:120−105=15 mmHg120 – 105 = 15\ mmHg120−105=15 mmHg

If >10 mmHg → Pulsus paradoxus present

Clinical Example

If:

• Sounds heard only in expiration at 118 mmHg
• Sounds heard throughout breathing at 102 mmHg

Then:118−102=16 mmHg118 – 102 = 16\ mmHg118−102=16 mmHg

→ Positive pulsus paradoxus

How to Demonstrate in Clinical Exam (Short Viva Answer)

You can say:

Pulsus paradoxus is demonstrated using a sphygmomanometer. The cuff is inflated above systolic pressure and slowly deflated. The first pressure at which Korotkoff sounds are heard only during expiration is noted. The pressure at which sounds are heard during both inspiration and expiration is then noted. The difference between these pressures is the pulsus paradoxus. A difference greater than 10 mmHg indicates pulsus paradoxus.

Important Clinical Associations

• Cardiac Tamponade (classic)
• Severe Asthma
• Tension Pneumothorax
• Constrictive Pericarditis

✅ Exam Tip:
If a patient has hypotension + raised JVP + pulsus paradoxus, suspect cardiac tamponade (Beck’s triad).

Introduction

Heart failure (HF) severity and progression are described using two complementary systems:

1. NYHA Functional Classification → based on symptoms and activity limitation
2. ACC/AHA Stages of Heart Failure → based on disease progression and structural changes

1. NYHA Functional Classification

Used in patients with established heart disease to assess symptom severity and functional limitation.

Class I

• No limitation of physical activity
• Ordinary physical activity does not cause symptoms
• Comfortable at rest

Examples

• Walking
• Climbing stairs normally
• Daily activities without dyspnea

Class II

• Slight limitation of physical activity
• Comfortable at rest
• Ordinary activity causes symptoms

Symptoms may include:

• Fatigue
• Palpitations
• Shortness of breath

Example

• Dyspnea when climbing several flights of stairs

Class III

• Marked limitation of physical activity
• Comfortable at rest
• Less than ordinary activity causes symptoms

Symptoms:

• Dyspnea
• Fatigue
• Palpitations with mild activity

Example

• Breathlessness when walking short distances

Class IV

• Severe limitation
• Symptoms even at rest
• Unable to perform any physical activity without discomfort

Examples

• Dyspnea at rest
• Orthopnea
• Severe fatigue

2. ACC/AHA Stages of Heart Failure

Describes development and progression of HF and emphasizes prevention.

Unlike NYHA classes, stages are progressive and irreversible.

Stage A – At Risk for Heart Failure

Patients without structural heart disease or symptoms but with risk factors.

Common risk factors:

• Hypertension
• Coronary artery disease
• Diabetes mellitus
• Metabolic syndrome
• Obesity
• Exposure to cardiotoxic drugs
• Family history of cardiomyopathy

Goal:

• Prevent development of structural heart disease

Stage B – Pre-Heart Failure

Patients without symptoms but with structural heart disease.

Examples:

• Left ventricular hypertrophy
• Previous myocardial infarction
• Reduced ejection fraction
• Valvular heart disease

Features:

• No symptoms yet
• Evidence of cardiac structural abnormalities

Goal:

• Prevent symptomatic HF

Stage C – Symptomatic Heart Failure

Structural heart disease with current or previous symptoms.

Common symptoms:

• Dyspnea
• Fatigue
• Reduced exercise tolerance
• Fluid retention (edema)

Patients often correspond to NYHA Class II–III.

Goal:

• Symptom control and prevention of hospitalization

Stage D – Advanced Heart Failure

• Severe symptoms despite optimal medical therapy
• Recurrent hospitalizations
• Marked limitation of daily activities

Management may include:

• Advanced therapies
• Mechanical circulatory support
• Heart transplant
• Palliative care

Patients usually correspond to NYHA Class IV.

Key Differences Between NYHA and ACC/AHA

Clinical Correlation

Typical relationship:

✔ Exam Pearl

• ACC/AHA = structural disease progression
• NYHA = symptom severity