Spinal Infections — MCQs
Osteomyelitis of spine is caused by the most common organism?
Minimum number of sputum samples required for diagnosis of TB by sputum smear microscopy according to RNTCP/NTEP guidelines:
Which of the following statements about Pott's spine is false?
A 38-year-old woman presents with a history of backache. X-ray and MRI of the spine reveal collapse of the D12 vertebra with normal intervertebral disc space. The LEAST likely diagnosis is:
Young female with 3 days fever presents with headache, BP 90/60 mmHg, Heart rate of 114/min, and pin point spots developed distal to BP cuff. Most likely organism is:
What is the most common sequela of tuberculous spondylitis in an adolescent?
A patient with a history of chronic ear infection now presents with manifestations, including headache and vomiting. A CT brain image is shown. What is the most probable diagnosis?
Prior to discharge of a patient with H. influenzae meningitis, the essential investigation to be done is?
Most common injection site infection in spinal anaesthesia
Pott's spine is most common at which specific region of the spine?
Spinal Infections Indian Medical PG Practice Questions and MCQs
Question 1: Osteomyelitis of spine is caused by the most common organism?
- A. Streptococcus
- B. Pseudomonas
- C. Mycobacterium tuberculosis
- D. Staphylococcus aureus (Correct Answer)
Explanation: ***Staphylococcus aureus*** - **_Staphylococcus aureus_** is the most common causative organism for **hematogenous osteomyelitis** in adults, including osteomyelitis of the spine. - It frequently gains access to bone through the bloodstream, leading to infection of the vertebral bodies. *Streptococcus* - While various species of **_Streptococcus_** can cause bone infections, they are **less common** than **_Staphylococcus aureus_** in vertebral osteomyelitis. - **Group A Streptococcus** primarily causes soft tissue infections, and **_S. pneumoniae_** is more associated with pneumonia and meningitis. *Pseudomonas* - **_Pseudomonas aeruginosa_** is a common cause of osteomyelitis, particularly in specific risk groups such as intravenous drug users, patients with puncture wounds (especially through footwear), or those with implanted medical devices. - It is **not the most common** overall cause of general osteomyelitis of the spine. *Mycobacterium tuberculosis* - **_Mycobacterium tuberculosis_** causes tuberculous spondylitis **(Pott's disease)**, which commonly affects the spine, leading to characteristic vertebral destruction and kyphosis. - While significant globally, it is **not the most common bacterial cause** of acute pyogenic vertebral osteomyelitis.
Question 2: Minimum number of sputum samples required for diagnosis of TB by sputum smear microscopy according to RNTCP/NTEP guidelines:
- A. Four
- B. Two (Correct Answer)
- C. Three
- D. One
Explanation: ***Two*** - According to **RNTCP/NTEP guidelines**, for diagnosis using **sputum smear microscopy**, two sputum samples are required: one **spot sample** (collected at the time of first visit) and one **early morning sample** (collected the next day). - This two-sample protocol provides adequate sensitivity for **acid-fast bacilli (AFB)** detection while reducing patient and laboratory burden. - **Note:** While CBNAAT is now the first-line diagnostic test requiring only one sample, sputum smear microscopy with two samples remains important where molecular diagnostics are unavailable. *One* - Although **CBNAAT (GeneXpert)** requires only one sputum sample and is the preferred first-line test under NTEP, this question specifically asks about **sputum smear microscopy**. - A single sample for smear microscopy has **lower sensitivity** and higher risk of **false negatives**, missing significant TB cases. *Three* - Earlier RNTCP protocols used a **three-sample approach** (spot-morning-spot), but this was simplified to **two samples** to improve efficiency without compromising diagnostic accuracy. - The reduction from three to two samples decreased patient burden and laboratory workload while maintaining adequate sensitivity. *Four* - Four samples are **not part of standard RNTCP/NTEP protocol** for pulmonary TB diagnosis via sputum smear microscopy. - Multiple samples beyond two may be considered in specific difficult-to-diagnose cases, but this exceeds the minimum requirement.
Question 3: Which of the following statements about Pott's spine is false?
- A. There is disc space narrowing on x-ray
- B. Back pain is an early symptom
- C. Commonest at dorsolumbar junction
- D. Always heals by chemotherapy (Correct Answer)
Explanation: ***Always heals by chemotherapy*** - This statement is false because while **chemotherapy** (anti-tubercular drugs) is the primary treatment for **Pott's disease** (tuberculosis of the spine), healing is not always guaranteed and can sometimes require **surgical intervention** in cases of severe neurological deficit or instability. - The success of treatment depends on early diagnosis, patient compliance, and the severity of the disease, and not all cases resolve completely without residual issues. *Commonest at dorsolumbar junction* - **Pott's spine**, or **vertebral tuberculosis**, most frequently affects the **thoracic** and **lumbar regions**, particularly the **dorsolumbar junction** (T9-L1). - This predilection is attributed to the rich vascular supply and increased mechanical stress in this area. *Back pain is an early symptom* - **Back pain** is often one of the **earliest and most common symptoms** of Pott's spine, due to inflammation and destruction of vertebral bodies. - The pain is typically **localized**, progressive, and may worsen with movement. *There is disc space narrowing on x-ray* - **X-rays** of Pott's spine often show **disc space narrowing** along with vertebral destruction and collapse, differentiating it from pyogenic osteomyelitis where disc spaces might be initially preserved. - This narrowing is a consequence of the tuberculous infection spreading from the vertebral body to the adjacent **intervertebral disc**.
Question 4: A 38-year-old woman presents with a history of backache. X-ray and MRI of the spine reveal collapse of the D12 vertebra with normal intervertebral disc space. The LEAST likely diagnosis is:
- A. Tuberculosis
- B. Metastasis
- C. Multiple myeloma
- D. Osteoporosis (Correct Answer)
Explanation: ***Osteoporosis*** - While osteoporosis can cause **vertebral collapse**, it typically results in a **wedging deformity** or uniform compression, usually without significantly affecting the intervertebral disc space [1]. - The patient's age (38 years old), while not precluding osteoporosis, makes it less likely to be the primary cause of a severe D12 collapse with normal disc space compared to other destructive processes. *Tuberculosis* - **Tuberculous spondylitis (Pott's disease)** commonly affects the vertebral body, often leading to its collapse (gibbus deformity) and subsequent **destruction of the intervertebral disc space** in later stages due to infection spread [2]. - The initial presentation with vertebral collapse and normal disc space followed by disc involvement is characteristic of tuberculous infection, making it a likely consideration. *Metastasis* - **Vertebral metastases** frequently cause osteolytic lesions that weaken the vertebral body, leading to collapse while often **sparing the intervertebral discs** initially due to their avascular nature [3]. - This presentation directly matches the description of D12 collapse with a normal disc space. *Multiple myeloma* - **Multiple myeloma** is a plasma cell malignancy that commonly causes **osteolytic lesions** in the spine, resulting in vertebral body collapse without significant involvement of the intervertebral discs. - This is a highly characteristic presentation for multiple myeloma, making it a strong differential for the given clinical and radiological findings.
Question 5: Young female with 3 days fever presents with headache, BP 90/60 mmHg, Heart rate of 114/min, and pin point spots developed distal to BP cuff. Most likely organism is:
- A. Brucella suis
- B. N. meningitidis (Correct Answer)
- C. Staphylococcus aureus
- D. Brucella abortus
Explanation: ***N. meningitidis*** - The presentation of **fever**, **headache** [1], signs of **shock** (hypotension, tachycardia), and **petechiae/purpura** (pinpoint spots distal to BP cuff, indicating a bleeding disorder such as thrombocytopenia or DIC often associated with meningococcemia) is classic for **meningococcal sepsis**. - *Neisseria meningitidis* is well-known for causing **rapidly progressive sepsis with disseminated intravascular coagulation (DIC)** and a characteristic **petechial or purpuric rash**. *Brucella suis* - *Brucella suis* causes **brucellosis**, which typically presents with **undulating fever**, **arthralgia**, fatigue, and hepatosplenomegaly. - While it can cause systemic illness, it does not typically manifest with the acute, severe presentation of **sepsis** and **hemorrhagic rash** seen in this patient. *Staphylococcus aureus* - *Staphylococcus aureus* can cause widespread infections, including sepsis characterized by **fever**, **hypotension**, and **tachycardia**, often leading to **toxic shock syndrome**. [2] - However, while *S. aureus* can cause skin manifestations like cellulitis or abscesses, it is less commonly associated with the specific **petechial rash** in the context of acute sepsis, unless it's an endocarditis with septic emboli, which would have a different clinical scenario. [2] *Brucella abortus* - Similar to *Brucella suis*, *Brucella abortus* causes **brucellosis**, a chronic zoonotic infection. - The clinical picture of **acute fulminant sepsis with hemorrhagic skin lesions** is not characteristic of *Brucella abortus* infection.
Question 6: What is the most common sequela of tuberculous spondylitis in an adolescent?
- A. Fibrous Ankylosis
- B. Pathological dislocation
- C. Chronic osteomyelitis
- D. Bony ankylosis (Correct Answer)
Explanation: ***Bony ankylosis*** - **Bony ankylosis** is a frequent outcome in successfully treated tuberculous spondylitis, particularly in adolescents due to their growth potential and robust healing responses. - The inflammatory process and subsequent healing, including bone repair, can lead to the fusion of vertebral bodies as the body attempts to stabilize the affected spinal segment. *Fibrous Ankylosis* - While **fibrous ankylosis** can occur, it's typically an earlier or less complete form of healing compared to bony ankylosis in the context of tuberculosis, which often leads to more extensive bone destruction and repair. - In adolescents, where osteoblastic activity is high, the body often progresses to a more stable bony fusion rather than a fibrous one. *Pathological dislocation* - **Pathological dislocation** is a severe complication that can occur due to extensive bone destruction and vertebral collapse, but it is not the most common sequela after treatment, especially with modern management. - Dislocation implies a loss of alignment and potentially severe neurological deficits, which are rarer than the healing process itself leading to fusion. *Chronic osteomyelitis* - **Chronic osteomyelitis** refers to persistent infection and inflammation within the bone. While tuberculous spondylitis is a form of osteomyelitis, if successfully treated, the infection is resolved, and the sequelae are related to the healing process itself (like ankylosis), not ongoing infection. - The question asks for the most common *sequela* (consequence of the disease or its treatment), assuming the infection has been managed.
Question 7: A patient with a history of chronic ear infection now presents with manifestations, including headache and vomiting. A CT brain image is shown. What is the most probable diagnosis?
- A. Meningitis
- B. Extradural Abscess
- C. Cerebral Abscess
- D. Temporal lobe Abscess (Correct Answer)
Explanation: ***Temporal lobe Abscess*** - The CT scan shows a **ring-enhancing lesion** with significant surrounding edema, which is characteristic of a **brain abscess**. - Given the history of a **chronic ear infection**, the temporal lobe is a common site for bacterial spread from the mastoid air cells or middle ear. *Meningitis* - Meningitis involves inflammation of the **meninges** and typically presents with diffuse changes on imaging, such as sulcal effacement or leptomeningeal enhancement, rather than a focal, encapsulated lesion. - While it can cause headache and vomiting, the CT image does not show findings typical of meningitis. *Extradural Abscess* - An extradural (or epidural) abscess is located **between the dura mater and the skull bone**. - It would typically appear as a collection outside the brain parenchyma, potentially causing mass effect but distinct from an intraparenchymal lesion seen in the image. *Cerebral Abscess* - The image does show a **cerebral abscess**, but this option is less specific than "Temporal lobe abscess." - The question asks for the **most probable diagnosis**, and combining the imaging findings with the patient's history of ear infection points to a specific location within the cerebrum.
Question 8: Prior to discharge of a patient with H. influenzae meningitis, the essential investigation to be done is?
- A. Developmental screening test
- B. ABER (Correct Answer)
- C. ECG
- D. EEG
Explanation: ***Correct: ABER*** - **Hearing loss** is a well-known and common complication following **H. influenzae meningitis**, making audiological assessment crucial before discharge. - An **Auditory Brainstem Response (ABR) test**, or ABER, is an **objective measure of hearing** that can detect sensorineural hearing loss, which might otherwise be missed in young children. - **Standard of care** recommends hearing assessment in all cases of bacterial meningitis prior to discharge as per IAP and AAP guidelines. *Incorrect: Developmental screening test* - While significant neurological insult from meningitis can affect development, a **developmental screening test** is not the *most essential* immediate post-meningitis investigation prior to discharge. - Neurological and developmental sequelae are typically assessed over time during follow-up rather than as a primary discharge screen. *Incorrect: ECG* - An **ECG (electrocardiogram)** assesses cardiac function and is generally not indicated for routine discharge after uncomplicated bacterial meningitis unless there are specific cardiac concerns. - **H. influenzae meningitis** primarily affects the central nervous system, not directly the heart. *Incorrect: EEG* - An **EEG (electroencephalogram)** measures brain electrical activity and is used to diagnose seizure disorders or assess for encephalopathy. - While seizures can be a complication, an EEG is typically performed if there are clinical signs of **seizure activity** or altered mental status, rather than as an essential routine discharge investigation for all patients.
Question 9: Most common injection site infection in spinal anaesthesia
- A. Bacteroides
- B. Staphylococcus (Correct Answer)
- C. Pseudomonas
- D. Streptococcus
Explanation: **Staphylococcus** - **_Staphylococcus_** species, particularly methicillin-sensitive _Staphylococcus aureus_ (MSSA) and methicillin-resistant _Staphylococcus aureus_ (MRSA), are the **most common culprits** in post-procedural infections like those following spinal anesthesia due to their presence on the skin. - These bacteria can cause various infections, from **superficial cellulitis** at the injection site to more serious complications like **meningitis** or an **epidural abscess**. *Bacteroides* - **_Bacteroides_** species are **anaerobic bacteria** commonly found in the gut flora, making them less likely to cause skin-puncture infections unless there is bowel injury or contamination. - While they can cause serious infections, they are **not typically associated** with superficial skin contamination leading to spinal anesthesia infections. *Pseudomonas* - **_Pseudomonas aeruginosa_** is known for causing opportunistic infections, especially in healthcare settings and in contact with water sources, but it is **not the most common cause** of injection site infections following spinal procedures. - Infections with **_Pseudomonas_** often present with a distinctive **grape-like odor** and a blue-green pus, which is not the typical presentation for initial injection site infections. *Streptococcus* - **_Streptococcus_** species can cause skin infections, but they are generally **less common than _Staphylococcus_** in injection site infections after spinal anesthesia. - While **Group A _Streptococcus_** can cause severe skin and soft tissue infections, it typically presents with **rapidly spreading cellulitis** rather than focal injection site issues.
Question 10: Pott's spine is most common at which specific region of the spine?
- A. Sacral
- B. Cervical
- C. Lumbosacral
- D. Thoracolumbar (T12-L1) (Correct Answer)
Explanation: **Thoracolumbar (T12-L1)** - The **thoracolumbar junction (T12-L1)** is the most common site for Pott's spine due to its biomechanical stress and vascular supply, making it a frequent location for spinal tuberculosis. - This region is susceptible to **compression fractures** and bone destruction, leading to kyphotic deformity (gibbus) in advanced cases. *Sacral* - While spinal tuberculosis can affect any part of the spine, the **sacral region** is considerably less common than the thoracolumbar junction. - Infections in the sacrum are often associated with other pelvic involvement or direct extension from adjacent sites. *Cervical* - Tuberculosis of the **cervical spine** can occur but is not as frequent as in the thoracolumbar region. - Clinical manifestations can include **neck stiffness, dysphagia**, and neurological deficits affecting the upper limbs. *Lumbosacral* - The **lumbosacral region** (L5-S1) can be affected by Pott's spine, but it is less common than the thoracolumbar junction. - Involvement here can lead to specific neurological symptoms like **foot drop** or radicular pain in the lower extremities.
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