Infectious Diseases Flashcards
A 15-year-old Asian girl with Down’s syndrome came to accident and emergency with a prolonged fever. She has severe learning difficulties and was difficult to assess. Her parents think she is more unsettled than usual and not eating and drinking properly for the last 3 weeks. She is admitted as you cannot confidently find the source of the infection, but she has no cough, rash, vomiting, diarrhoea or meningism. The next day she complains of a headache and starts to vomit. She has a CT scan which is normal and then a lumbar puncture (LP). White cell count (WCC) 150×109/L (20 per cent neutrophils), red blood count 0, protein 2 g/L, glucose 1.2 mmol/L (serum glucose 6.0 mmol/L). What is the most likely cause of this meningitis?
A. Mycobacterium tuberculosis
B. Herpes simplex virus (HSV)
C. Streptococcus pneumoniae
D. Cryptococcus neoformans
E. Neisseria meningitidis
A. Mycobacterium tuberculosis
1 AThe insidious onset of this case must raise the possibility of tuberculous meningitis (A). Although (C) and (E) are the most common causes of meningitis in the UK, the LP result and insidious nature make them less likely. An LP in these causes of meningitis may show raised white cells, normal protein and a glucose less than two-thirds of the serum glucose. Cryptococcus neoformans (D) is more likely in immunosuppressed patients, for example with coexisting HIV infection, which is not noted in this case. HSV results in encephalitis, which clinically is difficult to distinguish from bacterial meningitis so should be treated until you have confirmation that HSV is not present in the cerebrospinal fluid, which can now be done by laboratory test HSV polymerase chain reaction.
You are on elective in Uganda and spending the day on the paediatric ward. You are told that it is the rainy season and malaria is now becoming increasingly problematic. Almost all the children on the ward are suffering with the effects of malaria. The first child is a 5-year-old boy with a cyclical fever, abdominal pain and a 4 cm splenomegaly. He has 2 per cent parasitaemia on blood film. You are asked how you would treat this child. What is the best initial management step?
A. IM quinine
B. IV fluids and IV quinine
C. IV fluids and prophylactic splenectomy
D. Emergency splenectomy
E. Oral atovaquone
B. IV fluids and IV quinine
2 B This child has moderate parasitaemia. This child requires antimalarial treatment, IV in the first instance (B) and when he is improving this could be changed to oral (E). With splenomegaly secondary to acute haemolysis he should not have a splenectomy (C) or (D) unless there is evidence of a ruptured spleen; signs include hypovolaemic shock and peritonism. The first choice of antimalarial depends on the local resistance of the mosquitoes. This can be checked on national websites if the patient has just returned from travelling in endemic areas. It is also important to know what prophylaxis, if any, was taken and duration of the course.
A 3-year-old girl presents to accident and emergency with a 6-day history of fever and she is over 38°C when measured by her mother with a tympanic thermometer. She has become very miserable for the last few days. She has developed a rash on her trunk, which is blanching, erythematous and confluent. On examination, you also note bilateral non-purulent conjunctivitis, cervical lymphadenopathy, and a red tongue with lip cracking. Her extremities are also erythematous but not peeling. WCC 14×109/L, C-reactive protein 200 mg/L, and erythrocyte sedimentation rate 60 mm/hour. Blood culture is pending. What is the diagnosis?
A. Staphylococcal scalded skin
B. Toxic shock syndrome
C. Scarlet fever
D. Kawasaki’s disease
E. Measles
D. Kawasaki’s disease
3 DThis girl has all the features of Kawasaki’s disease (D). This is an inflammatory disease of unknown aetiology. It shares many features with all the other diagnoses listed, but may also have cardiac involvement in the form of coronary artery aneurysms. (A) causes a peeling of skin with a fever. (B) presents with a red macular rash, fever and usually an additional diarrhoeal illness. (C) presents with a sandpaper rash and erythematous mucous membranes. (E) is now an uncommon disease due to vaccination, though with reducing uptake of the MMR vaccine, cases are increasing, causing a febrile child with an erythematous, macular rash.
A 3-year-old boy presents with a right swollen eyelid. He has had a cold for the last week but his eyelid started swelling yesterday. He has had no injury or broken skin around the eye. On examination, his right eye is swollen and red, there is no discharge, he is now unable to open his right eye and he has proptosis. You are concerned about the complications of this infection. Within the last hour he has become more drowsy and started to vomit. His observations are all normal. What is the concerning complication in this case?
A. Visual loss
B. Abscess
C. Septicaemia
D. Orbital cellulitis
E. Meningitis
E. Meningitis
4 E All of these can be complications of periorbital cellulitis. This child, with reduced conscious level and vomiting, would raise concern about
meningitis (E) as the infection spreads to the cerebrospinal fluid around the optic nerve. All of these complications are worrying and require further investigation. Septicaemia (C) may also cause these symptoms if the child is in shock with poor perfusion of the brain. (A), (B) and (D) need to be excluded with CT head and ophthalmology review.
A 14-year-old girl presented to the GP with an enlarged lymph node in her neck. She first noticed it 3 weeks ago and it is increasing in size. She has also had a dry cough, fevers, night sweats and weight loss. She has had a poor appetite over the last 2 weeks, which her mother blames for her weight loss. There is no history of foreign travel or tuberculosis (TB) contacts. A chest x-ray shows a mediastinal mass. What is the most likely diagnosis?
A. Lymphoma
B. Pneumonia
C. TB
D. Lung tumour
E. Leukaemia
A. Lymphoma
5 AThere is a history of prolonged fever, which must raise the possibility of diagnoses other than infectious causes. There are no TB contacts and the x-ray does not show a focal collection, hence (C) and (B) are unlikely. The presence of a rapidly enlarging lymph node should prompt investigation for infection and malignancy. Primary lung cancer is rare in children, hence (D) is unlikely. Both (A) and (E) can present with lymphadenopathy and should be excluded with a lymph node biopsy and blood film/bone marrow aspirate. However, with the history of dry cough caused by a mediastinal mass and ‘B’ symptoms of fevers and night sweats, this should point towards (A) as the most likely diagnosis.
A 6-year-old girl presents to accident and emergency with a fever. She has no history of cough, cold, vomiting, diarrhoea, rash, headache or joint pain. On examination, she is tachycardic at 150 bpm and there are two petechial spots on her right ankle. Her capillary refill time is 4 seconds and she has cold feet. All her other observations are normal. What is the most appropriate course of action?
A. Inform the consultant about child protection concerns
B. IV ceftriaxone
C. IV fluid bolus and IV ceftriaxone
D. Admit to the ward for observation
E. Discharge home and advise to return if the rash spreads
C. IV fluid bolus and IV ceftriaxone
6 CThis girl is tachycardic and therefore should be investigated to find the cause. With the petechial spots in the presence of a fever and clinical signs of shock, one must consider meningococcal sepsis and commence antibiotics immediately. Since she has features of early shock, namely tachycardia and prolonged capillary refill time, she therefore requires a fluid bolus so (C) is correct, not (B). Although bruising must always raise suspicion and appropriate measures taken, in this case an alternative diagnosis is more likely; therefore (A) is not applicable on this occasion. She should not be sent home (E) as she is tachycardic. She needs prompt treatment after assessment to avoid progression to septic shock and therefore (D) is not appropriate.
A 3-year-old boy was brought to accident and emergency with his mother. She says he has been limping for a day now and refusing to walk for the last 2 hours. He has had a fever to 39°C which can be brought down with paracetamol. He has had no vomiting, diarrhoea, rash, cough, coryza or injury. He lives with his mother and is her only child. She is currently unemployed and has a background of depression. On examination of the right leg he has a swollen thigh and cries inconsolably when it is touched. It is red and tender. He refuses to allow movement of the hip either passive or active. The left leg is unremarkable on examination. What is the most likely diagnosis?
A. Perthes’ disease
B. Septic arthritis
C. Fractured femur due to accidental injury
D. Juvenile idiopathic arthritis
E. Fractured femur due to non-accidental injury
B. Septic arthritis
7 B This child has a fever and a limp, with limited movement and signs of acute inflammation in his right lower limb. The most likely diagnosis is septic arthritis of the right hip (B). He is too young for (A) which is due to avascular necrosis of the femoral head which usually occurs in children over 5 years of age. There is no history of trauma and therefore this makes (C) unlikely. (E) must remain a consideration, in particular in view of the social background. This history does not fit the definition of juvenile idiopathic arthritis (D), which is 6 weeks of joint pain and swelling which persists after other diagnoses have been excluded.
A pregnant woman attends her booking appointment at the antenatal clinic and has her routine blood tests done. She is now 13 weeks pregnant with her first child and you have a positive result for cytomegalovirus (CMV) IgM. You need to discuss the implications of CMV infection on her unborn child. Which of the following are not features of congenital CMV infection?
A. Deafness
B. Intrauterine growth retardation
C. Hydrocephalus
D. Thrombocytopenia
E. Congenital cardiac defects
E. Congenital cardiac defects
8 E CMV is the most common congenital infection acquired in pregnancy. It results in all the features in (A), (B), (C) and (D) after infection in the first trimester, but not (E). Cardiac defects are associated with other congenital infections such as rubella. Mothers are routinely screened for rubella, hepatitis B, HIV and syphilis in early pregnancy to ascertain risk to the fetus and treatment is given during pregnancy and may be required for the baby after birth.
A 5-year-old girl was admitted to the ward after she presented to her local accident and emergency with diarrhoea. She was passing 7–8 loose, watery stools per day for the last 4 days and had been vomiting for 1 day prior to this. There was blood in the stools and this had worried her mother. You ask about foreign travel and her mother reveals they had been in India until 2 weeks ago, staying with family and drinking tap water. She had no vaccines prior to travelling. On examination, she now has abdominal pain, swinging pyrexias, right upper quadrant tenderness but no rebound or guarding. You notice a pale pink (rose) spot on her trunk. What is the most likely infecting organism?
A. Rotavirus
B. Shigella spp.
C. Vibrio cholerae
D. Salmonella typhi
E. Escherichia coli 0157
D. Salmonella typhi
9 DAlthough the most common cause of infective gastroenteritis worldwide is rotavirus, causing over 50 per cent of all cases, this case has some unusual features, excluding (A). Cholera (C) presents with dysentery not just diarrhoea. Blood in the stool (although possible with severe rotavirus) is more commonly caused by bacteria. With the history of travel to India and the added risk factors of staying in the local community, a more tropical cause should be considered. The presence of rose spots indicates this is (D), excluding (B) and (E), though stool microscopy and culture will provide the definitive diagnosis with sensitivities for effective treatment.
A 10-month-old baby is brought to accident and emergency by ambulance having had a seizure. His mother reports that he went floppy suddenly and then his right arm and leg started shaking and he was not crying. It lasted less than 5 minutes and he was sleepy afterwards. He has had a fever and runny nose for the last 2 days and is off his food. Why is this not a febrile seizure?
A. He is too young
B. He has had a focal seizure
C. He has recently had a viral illness
D. The seizure lasted too long
E. The fever was not high enough
B. He has had a focal seizure
10 B Febrile seizures are common in children aged 6 months to 6 years, hence (A) is incorrect. The aetiology is unknown, but it is thought to occur with the rapid rise in temperature at the start of an infective illness, most commonly a viral illness in children, (C) is incorrect. There is no recognized range of temperatures, though there must be a documented fever, i.e. >37.5°C; therefore (E) is incorrect. A febrile convulsion by definition must be a generalized seizure that occurs in association with a fever, in a child with no neurological abnormality, hence (B) is the correct answer. Focal seizures are not categorized as febrile fits and this child requires imaging of the brain and to commence antibiotics (to cover Streptococcus pneumoniae and Neisseria meningitidis) and antivirals (to cover HSV) as this seizure may be secondary to meningoencephalitis. Seizures are categorized into simple (15 minutes, requiring medical treatment) but must fulfil the other criteria above; therefore (D) is incorrect.
