Serious & Notifiable Infections

Serious & Notifiable Infections UK Medical PG Question 1: A 58-year-old woman with diabetes presents with severe foot pain and a deep ulcer exposing bone. X-ray shows osteolytic changes. What is the most likely complication?

• A. Cellulitis
• B. Osteomyelitis (Correct Answer)
• C. Charcot arthropathy
• D. Peripheral arterial disease
• E. Deep vein thrombosis

Serious & Notifiable Infections Explanation: ***Osteomyelitis***- The combination of a **deep ulcer exposing bone** and radiologic evidence of **osteolytic changes** strongly indicates infection and destruction of the bone itself.- In patients with **diabetes**, foot ulcers often progress rapidly from soft tissue infection to bone infection due to underlying neuropathy and vascular disease.*Cellulitis*- Cellulitis is a superficial soft tissue infection characterized by erythema, swelling, and warmth, typically without **ulceration exposing bone**.- It affects the dermal and subcutaneous layers and does not cause **osteolytic changes** on X-ray.*Charcot arthropathy*- Charcot foot involves **neuropathic joint destruction** and deformity (e.g., *rocker-bottom* foot), but typically presents with little pain and diffuse bony fragmentation, rather than a localized deep, infected ulcer causing severe pain and lytic changes.- Although common in diabetes, pure Charcot arthropathy is usually sterile; the presence of a deep, draining ulcer points strongly to a progressive infection.*Peripheral arterial disease*- While PAD often contributes to ulcer formation (ischemic ulcers), these ulcers are typically **dry**, **punched-out**, and associated with diminished or absent pedal pulses.- PAD causes ischemia, but the identification of a deep ulcer exposing bone and active **osteolytic changes** points primarily toward a severe, established bone infection.*Deep vein thrombosis*- DVT involves clotting in a deep vein, presenting primarily with **unilateral swelling**, pain, and warmth in the leg (often calf or thigh).- It does not cause localized deep foot ulcers or underlying **osteolytic changes** in the bone.

Serious & Notifiable Infections UK Medical PG Question 2: A 22-year-old student presents with fever, headache, and a petechial rash on her legs. CSF shows: protein 2.1 g/L, glucose 1.8 mmol/L (serum 5.2), WCC 850 (90% neutrophils). What is the most likely organism?

• A. Streptococcus pneumoniae
• B. Neisseria meningitidis (Correct Answer)
• C. Haemophilus influenzae
• D. Listeria monocytogenes
• E. Enterovirus

Serious & Notifiable Infections Explanation: ***Neisseria meningitidis***- The classic presentation of fever, headache, and a **petechial rash** (indicating **meningococcemia**) in a young adult is highly characteristic of *Neisseria meningitidis* infection.- The CSF profilehigh protein, **low glucose** (low CSF/serum ratio), and **high white cell count** with **predominantly neutrophils** (90%)-is consistent with acute bacterial meningitis caused by this organism.*Streptococcus pneumoniae*- While *Streptococcus pneumoniae* is a common cause of bacterial meningitis with a similar CSF profile (high protein, low glucose, neutrophilic pleocytosis), it is less typically associated with a fulminant **petechial rash**.- This organism often affects extremes of age (very young or elderly) or individuals with specific risk factors such as **pneumonia**, **otitis media**, or **CSF leaks**.*Haemophilus influenzae*- *Haemophilus influenzae* type b (HiB) was a major cause of meningitis in **unvaccinated children** before widespread vaccination, making it less common in immunocompetent young adults.- Although it can cause bacterial meningitis with similar CSF findings, the striking **petechial rash** and patient's age make *Neisseria meningitidis* a more likely diagnosis.*Listeria monocytogenes*- *Listeria monocytogenes* typically causes meningitis in specific vulnerable populations, including **neonates**, the **elderly**, pregnant women, or the **immunosuppressed**.- Given the patient is a healthy 22-year-old student, *Listeria* is a less probable cause compared to *Neisseria meningitidis*.*Enterovirus*- **Enteroviruses** cause **aseptic (viral) meningitis**, which is characterized by a different CSF profile than seen here.- Viral meningitis typically presents with **normal CSF glucose**, normal or mildly elevated protein, and a **lymphocytic pleocytosis** (lymphocyte predominance), which contradicts the 90% neutrophil count in this case.

Serious & Notifiable Infections UK Medical PG Question 3: A 35-year-old man with HIV infection (CD4 count 80 cells/mm³, viral load 125,000 copies/mL, not on antiretroviral therapy) presents with a 4-week history of headache, fever, and confusion. CT head shows basal meningeal enhancement and multiple small nodules. Lumbar puncture shows: opening pressure 32 cmH2O, CSF white cells 45/mm³ (80% lymphocytes), protein 1.2 g/L, glucose 1.9 mmol/L (serum glucose 5.4 mmol/L). India ink stain is positive. Cryptococcal antigen is positive in both CSF and serum at titres of 1:2048 and 1:1024 respectively. He is started on liposomal amphotericin B and flucytosine. Which one of the following additional interventions has been shown to improve survival in this patient?

• A. Commencing antiretroviral therapy immediately alongside antifungal treatment
• B. Adding adjunctive dexamethasone 0.4 mg/kg daily for 6 weeks
• C. Performing daily therapeutic lumbar punctures until opening pressure normalizes (Correct Answer)
• D. Adding adjunctive interferon-gamma to enhance immune response
• E. Inserting a ventriculoperitoneal shunt to manage hydrocephalus

Serious & Notifiable Infections Explanation: ***Performing daily therapeutic lumbar punctures until opening pressure normalizes*** - Management of **elevated intracranial pressure** (opening pressure >25 cmH2O) is critical, as it is a major cause of mortality in **cryptococcal meningitis** associated with HIV. - Daily drainage of 20-30 mL of CSF is recommended to achieve an **opening pressure** of <20 cmH2O or a 50% reduction from baseline, which significantly **improves survival** and reduces neurological sequelae. *Commencing antiretroviral therapy immediately alongside antifungal treatment* - **Early initiation of ART** (within 2 weeks) in HIV-associated cryptococcal meningitis is associated with an increased risk of **Immune Reconstitution Inflammatory Syndrome (IRIS)** and higher mortality. - Current guidelines recommend deferring ART for **4 to 6 weeks** after the initiation of induction antifungal therapy to allow for partial clearance of the fungal load and reduce IRIS risk. *Adding adjunctive dexamethasone 0.4 mg/kg daily for 6 weeks* - Routine use of **corticosteroids** is contraindicated in cryptococcal meningitis as they have been shown to **increase mortality** and reduce fungal clearance rates in clinical trials. - Steroids also increase the risk of serious **adverse events** without providing any survival benefit in these patients. *Adding adjunctive interferon-gamma to enhance immune response* - While **interferon-gamma** may facilitate faster fungal clearance in some experimental settings, it has not been shown to provide a **survival benefit** in high-quality clinical trials for HIV-associated cryptococcal meningitis. - It is not currently recommended as part of the **standard induction therapy** for this condition. *Inserting a ventriculoperitoneal shunt to manage hydrocephalus* - **Ventriculoperitoneal (VP) shunts** are generally reserved for patients who fail to respond to repeated **therapeutic lumbar punctures** or develop persistent symptomatic hydrocephalus refractory to medical management. - Although useful for long-term pressure management, it is not the primary or first-line intervention for improving **acute survival** compared to serial lumbar punctures, which are less invasive and carry fewer immediate risks.

Serious & Notifiable Infections UK Medical PG Question 4: A 25-year-old woman presents with a 2-week history of sore throat, fever, and fatigue. She has cervical lymphadenopathy and splenomegaly. Her throat swab is negative for Group A Streptococcus. What is the most likely diagnosis?

• A. Viral pharyngitis
• B. Infectious mononucleosis (Correct Answer)
• C. Bacterial pharyngitis
• D. Diphtheria
• E. Candidiasis

Serious & Notifiable Infections Explanation: ***Infectious mononucleosis***- The constellation of prolonged **fever**, **pharyngitis**, diffuse **lymphadenopathy**, and **splenomegaly** in a young adult is the classic presentation of primary infection with **Epstein-Barr Virus (EBV)**.- The relatively long duration of symptoms (2 weeks), the presence of **splenomegaly**, and the **negative Group A Strep swab** strongly suggest infectious mononucleosis.*Viral pharyngitis*- Common viral causes (e.g., rhinovirus, adenovirus) usually result in an acute illness, lasting less than 10 days, and do not typically cause sustained systemic symptoms or significant **splenomegaly**.- While presenting with sore throat and fever, non-EBV viral pharyngitis lacks the profound, persistent **fatigue** and notable **lymphadenopathy** seen in infectious mononucleosis.*Bacterial pharyngitis*- This is typically caused by *Streptococcus pyogenes* (Group A Strep), which was **ruled out by the negative throat swab**.- **Bacterial pharyngitis** rarely causes the sustained constitutional symptoms and concurrent **splenomegaly** seen in this case.*Diphtheria*- The hallmark of **diphtheria** is the presence of a thick, adherent, gray-white **pseudomembrane** on the tonsils and pharynx, which is not described in this patient.- It is rare in vaccinated populations and often leads to severe systemic toxicity (e.g., **myocarditis**) rather than the classic infectious mononucleosis triad.*Candidiasis*- Pharyngeal **candidiasis (thrush)** presents as white, easily removable plaques, often favored by antibiotic use or **immunosuppression**.- It is primarily a localized mucosal infection and usually does not cause the fever, systemic illness, or **splenomegaly** seen here.

Serious & Notifiable Infections UK Medical PG Question 5: A 62-year-old man with diabetes presents with a foot ulcer and fever. X-ray shows bone destruction. Blood cultures grow Staphylococcus aureus. What is the recommended antibiotic duration?

• A. 2 weeks
• B. 4 weeks
• C. 6 weeks
• D. 8-12 weeks (Correct Answer)
• E. 6 months

Serious & Notifiable Infections Explanation: ***8-12 weeks***- This prolonged duration is typically recommended for **diabetic foot osteomyelitis (DFO)**, especially when complicated by **Staphylococcus aureus bacteremia** and radiographic evidence of **bone destruction**.- The extended treatment ensures adequate eradication of bacteria from the poorly vascularized bone, which is crucial in diabetic patients prone to **recurrence**.*2 weeks*- This duration is vastly insufficient for established **osteomyelitis**, which requires prolonged therapy due to poor antibiotic penetration into bone and the potential for **biofilm** formation.- A 2-week course is generally reserved for uncomplicated **soft tissue infections** or **cellulitis**, not for deep bone infections with systemic involvement.*4 weeks*- While sometimes used for acute, uncomplicated osteomyelitis without extensive bone involvement, **4 weeks** is typically inadequate for severe cases like **DFO** with **bacteremia** and significant **bone destruction**.- In such complex scenarios, a shorter course significantly increases the risk of **treatment failure** and **relapse**.*6 weeks*- **6 weeks** is considered the standard minimum duration for acute, uncomplicated osteomyelitis, particularly after successful **surgical debridement** of infected bone.- However, for complicated DFO with **S. aureus bacteremia** and significant bone destruction, a longer course, often up to 12 weeks, is frequently necessary, especially if debridement is limited.*6 months*- This exceptionally long duration is generally reserved for very specific, highly refractory infections, such as **tuberculosis osteomyelitis**, or for chronic suppressive therapy in certain **prosthetic joint infections**.- It is typically excessive for **Staphylococcus aureus** DFO when managed with appropriate initial therapy and a standard prolonged course (8-12 weeks).

Serious & Notifiable Infections Flashcard 1 of 5

Question: The mnemonic FROM JANE describes the symptoms of _____

Answer: infective (bacterial) endocarditis

Serious & Notifiable Infections Flashcard 2 of 5

Question: COVID-19 may cause complications including _____, MI, ARDS, Septic shock

Answer: AKI

Serious & Notifiable Infections Flashcard 3 of 5

Question: Women who are HIV positive should be offered _____ cervical cancer screening

Answer: annual

Serious & Notifiable Infections Flashcard 4 of 5

Question: Penicillin G is given to a patient with syphilis. They develop fever, chills, & myalgias within 12-48 hours. What is the likely diagnosis? _____

Answer: Jarisch-Herxheimer reaction

Serious & Notifiable Infections Flashcard 5 of 5

Question: Severe COVID-19 may present with _____, Pneumonia, shock and hypoxia

Answer: ARDS