Infections are an essential topic for the NEET PG exam since it is the major cause of morbidity and mortality in patients and understanding their pathogenesis, diagnosis, and management is crucial for a medical practitioner.
Questions on infections are common in the NEET PG exam and are used to assess the candidate's knowledge of medical microbiology and infectious diseases.
Overall, infections are an integral part of medical education and are an important topic for NEET PG. So, in this blog we have covered the topic in brief.
CAUSATIVE AGENTS
MC – Staphylococcus aureus – involves metaphysis
Exceptions
Sickle cell anaemia – Salmonella – Diaphyseal
IV drug abuser – Pseudomonas
Foot puncture wound – Pseudomonas
Open injuries – Staphylococcus
Human bites – Eikenella
Animal bites – Pasteurella
Important Information Salmonella can cause multifocal osteomyelitis and involve different areas of the body in sickle cell anaemia patients
MC LOCATIONS – OSTEOMYELITIS
Lower end of femur
For Adults – Spine (vertebral body)
For Joint – Knee (most common)
DEFORMITIES AT HIP
Important Information Positions that a joint can attain in lower limbs - Faber - Position where hip has more capacity Fadir - Opposite of it
FABER – Flexion, Abduction, External rotation
Causes
Synovitis (idiopathic, transient, tubercular)
Infection - Septic arthritis - misnomer, pus in the joint (pyogenic)
Iliotibial band contracture (polio)
Anterior dislocation
FADIR - Flexion, Abduction, Internal rotation
Causes
Posterior dislocation
Arthritis
Important Information Dislocation of Hip - Posterior dislocation > Anterior dislocation
TOM SMITH ARTHRITIS – HYPERMOBILE HIP
Joint is totally destroyed
Initially movements are absent
Later, head/capital epiphysis of femur is destroyed → Hypermobility and Instability of joint
Usually movements are absent in infection of limb or joint
Tom Smith Arthritis is an exception
BRODIE'S ABSCESS
Subacute osteomyelitis > Chronic osteomyelitis
Upper end femur
Sclerotic margin (means good immunity - so not seen in HIV +ve)
CHRONIC OSTEOMYELITIS
Sequestrum – dead bone (cause of sinus)
Involucrum – reactive bone (surrounding sequestrum)
Cloacae – sinuses through involucrum
Complications – Amyloidosis, malignancy
MRI – RIM sign
Paprika sign - While removing the dead bone, there is presence of bleeding from the live bone underneath the dead bone known as paprika sign
The instruments Shown here are Bone Nibbler, Bone cutter.
Tenderness along tendon sheath → Most specific (Percussion tenderness)
Important Information Infection of the thumb can involve the little finger because of connecting bursa.Index, middle & ring fingers have separate sheaths.Therefore, infection of the little finger can involve thumb but not index finger.
MYCETOMA
Eumycetoma
Actinomycetoma
Fungal cause
Bacterial cause
Multiple draining sinus over foot
Multiple draining sinus over mandible
Above waist - Bacterial cause
Below waist - Fungal cause
MRI
Dot in circle sign
Painless conditions
Mycetoma
Charcot's joint
PRACTICE QUESTIONS
Q True/False in view of septic arthritis?
Widening of joint space is there
Staph aureus is the most common organism in young children & neonates
I/D done after culture & aspirate & antibiotics for 24 hrs
Kocher’s criteria is used to differentiate from transient synovitis
Position of hip is FADIR
Ans - F, T, F, T, F
KOCHER’S CRITERIA
Patient is not able to bear weight
ESR ≥40 mm/hr
Fever > 38.5°C
WBC > 12,000 cells/µl
Important Information From 3% for one positive to more than 90% for four positive is the sensitivity of Kocher’s criteria
Q. Synovial tenosynovitis of flexor tendon. What is the correct statement?
The affected finger is extended at all joints
It has to be conservatively managed
Little finger infection can spread to thumb but not to index finger
Patient presents with minimal pain
Ans - Little finger infection can spread to thumb but not to index finger
Q. Multifocal osteomyelitis is associated with?
SAPHO syndrome
Sickle cell anaemia
Thalassemia
Salmonella infection
Ans - Sickle cell anaemia
Q. In osteomyelitis of the spine, the most common causative organism is?
Staphylococcus aureus
Pseudomonas
Tuberculosis
Streptococcus
Ans - Staphylococcus aureus
Important Information In case of any bone in the body king of orthopedics is Staphylococcus aureus
Previous Year Question
Q. A young girl had thigh swelling with discharging sinus from which bony fragment came out. The parents were concerned what was it? (FMGE – Aug - 2020)
A. Involucrum
B. Cloacae
C. Sequestrum
D. Loose body
Q. Which of the following is not true about the given image?(FMGE – Aug - 2020)
A. May cause Osteomyelitis
B. May be caused due to pin prick injury
C.Causative Organism is staph epidermidis
D. May be treated initially by antibodies
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