Infectious Diseases Recognised features of infectious mononucleosis include: A Palatal petechial haemorrhages
(True)
B Aseptic meningitis
(True)
C Vesicular rash on neck and trunk
(False)
D Raised asparatate amino transferase
(True)
E Splenomegaly
(True)
Comments: Incubation period of infectious mononucleosis is 30-60 da ys. Results of infection:
1. Asymptomatic (most) 2. Simple infection: fever, malaise, headache, myalgia, m yalgia, worsening sore throat abdominal pain. Splenic enlargement in 50% to 2-3cm. 90% have lymphadenopathy and 10% liver enlargement. Severe pharyngitis with exudate and petechiae is often present, and maculopapular rash will occur in 80% given Amoxycillin. 3. Complications: • • • • •
Splenic rupture with trauma (<0.2%). Stridor or respiratory distress, which may be treated with steroids. CNS: ataxia, fits, Alice in Wonderland Syndrome, Guillain Barre. Haematology: Haemolytic anaemia, aplastic anaemia. Other: Myocarditis, intesitial pneumonitis, pancreatitis, parotitis and orchitis.
Copyright © 2002 Dr Colin Melville
BCG vaccination: A is contraindicated in neonates
(False)
B is a killed polysaccharide antigen vaccine
(False)
C should be given to all children who have a strongly positive tuberculin test
(False)
D is presently routinely offered in the UK at age 16 years
(False)
E also provides protection against leprosy
(True)
Comments: a - BCG vaccine vaccine may given given to newbor newborns ns at high high risk of of exposure. exposure. b - The BCG vaccine vaccine is an attenuated strain - it provides approximately 70% protection. c - It should NOT be given to these children. A low reactivity Heaf test (grade 0 - 1) should be documented before administration. d- BCG is given at Comprehensive school entry (age 11 - 13). e - It has also found a use in stimulating the immune system for the treatment of some cancers.
Presenting features of HIV infection in childhood include: A Persistent oral thrush beyond the neonatal period
(True)
B Hepatosplenomegaly
(True)
C Failure to thrive
(True)
D Bilateral perihilar infiltrates on chest x-ray
(True)
E Recurrent otitis media
(True)
Comments:
Post-neonatal thrush suggests cell-mediated immune deficiency if the child has not had broad-spectrum antibiotics. Hepatosplenomegaly and lymphadenopathy are characteristic. Lymphoid interstitial pneumonitis (LIP) is a common finding, particularly in Africans. Recurrent common bacterial infections occur in early disease, disease, with pneumocystic pneumonia, pneumococcal septicaemia being disseminated CMV making further decline in their immunity. Copyright © 2002 Dr Colin Melville
Clinical features of toxoplasmosis include: A microcephaly
(True)
B choroidoretinitis
(True)
C cervical lymphadenopathy
(True)
D mouth ulcers
(False)
E sacroiliitis
(False)
Comments:
Comments: a - BCG vaccine vaccine may given given to newbor newborns ns at high high risk of of exposure. exposure. b - The BCG vaccine vaccine is an attenuated strain - it provides approximately 70% protection. c - It should NOT be given to these children. A low reactivity Heaf test (grade 0 - 1) should be documented before administration. d- BCG is given at Comprehensive school entry (age 11 - 13). e - It has also found a use in stimulating the immune system for the treatment of some cancers.
Presenting features of HIV infection in childhood include: A Persistent oral thrush beyond the neonatal period
(True)
B Hepatosplenomegaly
(True)
C Failure to thrive
(True)
D Bilateral perihilar infiltrates on chest x-ray
(True)
E Recurrent otitis media
(True)
Comments:
Post-neonatal thrush suggests cell-mediated immune deficiency if the child has not had broad-spectrum antibiotics. Hepatosplenomegaly and lymphadenopathy are characteristic. Lymphoid interstitial pneumonitis (LIP) is a common finding, particularly in Africans. Recurrent common bacterial infections occur in early disease, disease, with pneumocystic pneumonia, pneumococcal septicaemia being disseminated CMV making further decline in their immunity. Copyright © 2002 Dr Colin Melville
Clinical features of toxoplasmosis include: A microcephaly
(True)
B choroidoretinitis
(True)
C cervical lymphadenopathy
(True)
D mouth ulcers
(False)
E sacroiliitis
(False)
Comments:
Causes for Microcephaly include; * down's syndrome * congenital rubella * congenital toxoplamosis * congenital CMV * cri du chat syndrome * seckel'syndrome * rubinstein-taybi syndrome * trisomy 13 * trisomy 18 * smith-lemli-opitz syndrome * cornelia de Lange syndrome * uncontrolled maternal phenylketonura * methylmercury poisoning
The following are features of congenital toxoplasmosis: A Generalised lymphadenopathy
(True)
B Microcephaly
(True)
C Thrombocytopenia
(True)
D Intracranial calcification
(True)
prognosis without without treatment treatment E A good prognosis
(False)
Comments: Congenital toxoplasmosis, fortunately rare, is associated with the usual manifestations of congenital infection: IUGR, thrombocytopaenia, intracranial calcification, chorioretinitis. Hydrocephalus is more common, but microcephaly microcephal y well described. described. Most cases are unaffected, but may present with chorioretinitis many years later. The incidence used to be highest in France, because of their penchant for eating uncooked meat, but public health measures have reduced the incidence there. Copyright © 2002 Dr Colin Melville
IgA: A Is involved in mucosal immunity.
(True)
B Have 4 distinct sub-groups.
(False)
C Activates complement via the classical pathway.
(False)
D Is manufactured in lymph nodes.
(True)
E Crosses the placenta.
(False)
Comments:
IgA is the major antibody in serology: tears, sweat, lung, gut, urine. IgA avoids digestion by the presence of the secretory piece which is added as it is secreted onto the mucosa. It is an important defence
against surface binding of micro-organisms. There are 2 sub-types, IgA1 and IgA2. Only IgG is transferred across the placenta. Complement proteins circulate, therefore, they rarely come into contact with IgA. Copyright © 2002 Dr Colin Melville
In ataxia telangiectasia: A Inheritance is X-linked recessive.
(False)
B The usual presentation is with lower respiratory infections.
(False)
C Chromosome fragility is increased.
(True)
D The immunodeficiency primarily affects phagocyte function.
(False)
E Chronic thrombocytopenia is an important feature.
(False)
Comments: Ataxia telangiectasia is an autosomal recessive disorder, with a defect that has now been localised to chromosome 11q 22-23. Ataxia occurs when a child first begins to walk, and subsequently, recurrent sino-pulmonary infections occur. Telan giectasiae become evident at 3-6 years, because of the DNA repair defects (similar defects are found in Fanconi's anaemia and Bloom's Syndrome). The immune deficiency is variable, with the commonest being an IgA deficiency. Thrombocytopenia suggests Wiskott-Aldrich Syndrome, particularly in a boy with immune deficiency and eczema.
Copyright © 2002 Dr Colin Melville
The following conditions are thought to have an atopic basis: A Seborrhoeic dermatitis
(False)
B Dermatitis in response to nickel
(False)
C Anaphylactic reaction to peanuts
(True)
D Hereditary angio-neurotic oedema
(False)
E Cow's milk protein intolerance
(True)
Comments:
Seborrhoeic dermatitis is a condition of unknown aetiology, and is associated with
greasy scales found on the scalp, forehead, cheeks. The patients are very well in themselves, and have no particular itching. In atopic dermatitis the skin lesions tend to be more on the cheeks, and later become flexural. Nickel dermatitis is a contact dermatitis. C1 inhibitor deficiency is hereditary angio-neurotic oedema. This is associa ted with abdominal pain in adolescence, but can occasionally involve life-threatening airway obstruction. Cow's milk intolerance is strongly associated with atopy. Copyright © 2002 Dr Colin Melville
Recognised causes of polyarthritis in children include: A Mumps
(True)
B Rubella
(True)
C Idiopathic thrombocytopenic purpura
(False)
D Henoch Schonlein purpura
(True)
E Acquired hypogammaglobulinaemia
(False)
Comments: Recognised causes of polyarthritis in children include: • • • •
Juvenile chronic arthritis. Septic arthritis: including Reiter's, gonococcus, MTB. Post-infectious: including rubella, mumps, parvovirus, hepatitis B and HSP. In immunocompromised patients: Aspergillus, mycoplasma, enteroviral, arthritidies.
Polyarthritis is a common condition, and has bo th infectious and non-infectious causes: • • •
Viral: enterovirus infection, mumps, rubella, fifth disease, hepatitis B. Bacterial: campylobacter, rat bite fever, and is also found in meningitis. Inflammatory: Henoch Schonlein Purpura, inflammatory bowel disease, Reiter's Syndrome, rheumatic fever, Sjogren's Syndrome, systemic lupus erythematosis, psoriasis.
Copyright © 2002 Dr Colin Melville
The following statements are true about immunological reactions: A Serum sickness is caused by a type II reaction.
(False)
B Grave's Disease is caused by a type IV reaction.
(False)
C Angio-neurotic oedema is the most severe form of type I reaction.
(False)
D Urticaria usually responds to Cimetidine.
(False)
E Deficiencies in the terminal components of complement increase the risk of meningococcal disease.
(True)
Comments:
Serum sickness is due to circulating antibody-antigen complex es (Type III). Grave's Disease is due to stimulating antibody (Type VI). The mo st severe variety of Type I reaction is anaphylaxis, with angio-oedema an intermediate reaction associated with wheeze and swelling of the lips and severe urticaria. These reactions are mediated b y histamine 1 receptor stimulation. Congenital C1 inhibitor deficiency is also caused hereditary angio-oedema. Deficiencies in C1r, s, an d 2-4 result in vasculitidies; while deficiencies in C2, 3 and 5-8 are associated with an increased risk of septicaemia. Copyright © 2002 Dr Colin Melville
The following forms of encephalitis are caused by a neuroimmunological response: A Herpes simplex
(False)
B Measles
(True)
C HIV infection
(False)
D Enteral viruses
(False)
E Cytomegalovirus
(False)
Comments:
Encephalitis may be caused by:
• •
•
Direct invasion by a neurotoxic virus (encephalitis). Post-infectious encephalopathy: delayed brain swelling because of an immunological response to the antigen. Slow virus infection, e.g. HIV or SSPE.
Direct infection is most commonly caused by enteral v iruses, HSV 1 and 2, varicella, CMV, and EBV. It is also occasionally caused by respiratory viruses, HHV6, rubella or mumps. A post-infectious illness may also be caused b y measles or varicella zoster (cerebellar ataxia). Copyright © 2002 Dr Colin Melville
Causes of confusion and seizures in patients with AIDS include: A Toxoplasmosis
(True)
B Progressive multifocal leuconencephalopathy
(True)
C Cryptococcal meningitis
(True)
D AIDS-dementia complex
(True)
E CMV
(True)
Comments: PML is a progressive infection of oligodendroglial cells by JC papovirus in immune deficiency. Invariably fatal, but uncommon in children with HIV. Copyright © 2002 Dr Colin Melville
In herpes simplex encephalitis: A brain MRI is characteristically normal
(False)
B temporal lobe involvement is common
(True)
C fits are uncommon
(False)
D cold sores or genital herpes are usually present
(False)
E viral identification by PCR on cerebrospinal fluid is no n-specific
(False)
Comments: MRI brain normally shows changes in the temporal lobes. Presenting features include fever, headache, vomiting, reduced consciousness and seizures. There may be dysphasia, hallucinations and peculiar behaviour. There are usually no skin manifestations of herpes simplex infections. The virus is rarely isolated from CSF but
may be detected by PMR.
Methicillin-resistant Staphyloccus aureus (MRSA) is: A an invasive organism when compared to methicillin sensitive strains of Staphyloccus aureus.
(False)
B resistant to methicillin is due to a plasmid
(True)
C a cause of nosocomial pneumonia
(True)
D mostly responds well to vancomycin therapy
(True)
E a cause of toxic shock syndrome.
(True)
Comments: MRSA usually colonises wounds and venous access sites. Theoretically can cause toxic shock which is often due to MRSA elaborating TSS toxins.
The follwing are true of rabies virus infection: A it can be carried by foxes for several weeks
(False)
B it can be harmless to small animals
(True)
C it is found only in the brain at autopsy
(False)
D fatal infections always make dogs mad
(False)
E it can have an incubation period longer than 6 months
(True)
Comments: Foxes usually die within 10 days of contracting rabies. The virus can be found in many tissues and is transmitted through saliva.
Mycoplasma infection is associated with: A Severe prolonged headache
(True)
B Peripheral neuropathy
(True)
C Myocarditis
(True)
D Erythema multiforme
(True)
E Erythema nodosum
(True)
Comments: Mycoplasma usually begins with coryza and slow-onset pnu monia with systemic upset. Symptoms are more impressive than signs. Infective complications include upper respiratory tract infection, croup, sinusitis, bronchiolitis, and it can precipitate asthma. Autoimmune complications include skin, CNS, cardiac, G I and joint problems. Copyright © 2002 Dr Colin Melville
Regarding septic shock: A The peripheries may be warm.
(True)
B Bacterial lipopolysaccharide may be important in its aetiolog y.
(True)
C Capillary leak results from an uncontrolled immunological response.
(True)
D Tumour necrosis factor alpha and interleukin 1 levels are typically elevated.
(True)
E Fluid resuscitation required may exceed the theoretical blood volume of a healthy child of the same weight.
(True)
Comments:
Bacterial LPS from G-ve cell wall or lipoteichoic acid from G+ve activate a cytokine cascade, tumour necrosis factor, interleukin0, 6, 8, p latelet activating factor and interferon gamma. This triggers complement, the coagulation cascade, and the kallikrein system. Polymorphs are activated and ACTH production stimulated. Peripheral vasodilatation, late vasoconstriction, myocardial depression, hypotension, ventilatory insufficiency and lactic acidosis occur. Multiorgan failure can result. Copyright © 2002 Dr Colin Melville
The following may occur in infectious mononucleosis: A Vesicular rash
(False)
B Jaundice
(True)
C Thrombocytosis
(False)
D Atypical lymphocytes
(True)
E Presentation commonly before the age of 30 years
(True)
Comments:
The rash is usually maculopapular. Jaundice is rare. In 10% the liver will be palpable and 50% the spleen will be palpable, 90% have tonsillar lymphadenopathy. Pharyngitis and is common. WCC 10-20k (30% at ypical lymph). Mild thrombocytopenia in 50% of cases. Rare in children less than 4 years of age, and rare in adults over 40 years of age. Copyright © 2002 Dr Colin Melville
Falciparum malaria: A acute infection is not associated with splenomegaly
(False)
B is associated with periodic fever in a minority of cases
(True)
C has an incubation period of 8-15 days
(True)
D may present as a gastroenteritis
(True)
E may be treated with primaquine
(False)
Comments: Falciparum malaria has an incubation period of 8-15 days and is frequently associated with splenomegaly and unlike the o ther malarias does not cause a typical periodic fever. Features include high fever, headaches, chills, arthralgia and gastroenteritis. It is treated with quinine as frequently it is chloroquine resistant and primaquine is used for prophylaxis not treatment.
In a 6 month old child with meningitis, the following organisms should be covered by first line antibiotic therapy: A Group B Streptococcus
(False)
B Listeria monocytogenes
(False)
C E. Coli
(False)
D Haemophilus Influenzae Type B
(True)
E Pseudomonas.
(False)
Comments:
Antibiotics should be selected according to the common organisms prevalent at various ages. Currently, in the UK these are: •
•
•
<3 months of age: Group B Streptococcus, E. Coli or other gram negatives, Listeria. 1 month - 6 years of age: Meningococcus, Pneumococcus, Haemophilus Influenzae. The incidence of the latter has declined since the introduction of Hib vaccine, but it should still be covered. >6 years: Meningococcus, Pneumococcus.
Copyright © 2002 Dr Colin Melville
Metronidazole: A Inhibits dihydrofolate reductase.
(False)
B Has 80% bioavailability if given rectally.
(True)
C Has harmful effects with alcohol.
(True)
D Causes coloured urine.
(True)
E Causes peripheral neuropathy.
(True)
Comments: Reduced to active derivative which binds to DNA and inhibits acid synthesis. Disulfiram reaction with alcohol. Some types of Warfarin. Metallic taste, hypotension, peripheral neuropathy.Copyright © 2002 Dr Colin Melville
AZT (Azidothymidine): A Is a uridine analogue.
(False)
B Inhibits reverse transcriptase.
(True) 9
C Is contraindicated if neutrophil count <0.75 x 10 /L.
(True)
D Reduces vertical transmission of HIV infection.
(True)
E Causes thrombocytopenia.
(True)
Comments: AZT is a thymidine analogue which inhibits reverse transcriptase. Neutropenia is a relative contraindication. Side effects include thrombocytopenia, neutropenia, and
nausea. Rapid resistance develops due to an error-prone replication of the HIV virus and rapid mutations. AZT is particularly useful for preventing vertical transmission from mother to child. Copyright © 2002 Dr Colin Melville The following are characteristic of early tetanus: A Rigid abdomen
(True)
B Rigid jaw muscles
(True)
C Dysphagia
(True)
D Hyperpyrexia
(True)
E Carpopedal spasm
(False)
Comments:
Infantile generalised tetanus develops within 302 days of birth. The usual picture is of poor feeding, hunger crying, paralysis and decreased movement. The child becomes stiff with muscular spasms and opythotomis. A contaminated umbilicus may be obvious. The fever is usually secondary to muscular spasm (muscular energy). Carpopedal spasms -/+ laryngospasm occurs in manifest tetany due to extreme vitamin D deficiency, hypomagnesiaemia or hypocalcaemia. The wrists are flexed with extended fingers and aducted thumbs with extended and aducted feet. Latent tetany refers to carpopedal spasm occurring on ischaemia of the motor nerves caused by blowing up of a blood pressure cuff. Copyright © 2002 Dr Colin Melville
Influenzae vaccine is recommended in the following patients: A HIV infected child
(True)
B Chronic purulent lung disease
(True)
C Acute lymphoblastic leukaemia patient
(True)
D Chronic heart disease
(True)
E Severe cerebral palsy/mentally retarded
(True)
Comments:
Frequent genetic reassortments make vaccine production difficult. Currently, a trivalent vaccine is used consisting of 2 types of 2 strains of type A and one strain of
type B based on last year's circulating viruses. Usual protection is about 75%, although this will reduce in pandemic years. Recommendations are that the following receive influenza vaccine: 1. Diseases: a) Chronic respiratory disease including asthma. b) Chronic he art disease. c) Chronic renal failure. d) Diabetes mellitus. e) Immunosuppression due to disease or treatment including asplenia or splenic dysfunction. 2. Those in residential homes. Copyright © 2002 Dr Colin Melville
Recognised complications of chickenpox infection include: A Pneumonitis
(True)
B Pancreatitis
(True)
C Subacute encephalitis
(True)
D Cerebellar encephalitis
(True)
E Erythema marginatum
(False)
Comments: Complications of chickenpox include: •
• • • • • • •
Superinfection (Staph. and Strep.), which rarely results in varicella gangrenousum, arthritis, osteomyelitis, and pneumonia. Encephalitis/ cerebellar ataxia. Reye's, hepatitis, or pancreatitis. Thrombocytopenia. Nephritis, nephrosis, or haemolytic uraemic syndrome. Myocarditis or pericarditis. Orchitis. 9 Pneumonitis (immunocompromised with lymphocyte count < 0.5x10 /L, newborn or pregnant).
Copyright © 2002 Dr Colin Melville
The following conditions may be significantly worsened by concurrent corticosteroid or cytotoxic drug therapy: A tuberculosis
(True)
B amoebiasis
(True)
C strongyloides
(True)
D giardiasis
(False)
E ascariasis
(False)
Comments: a-easy, b!, c-may precipitate intestinal perforation
The following are recognised features of Lyme disease: A Recurrent headache
(True)
B Seventh nerve facial palsy
(True)
C Behavioural change
(True)
D CSF neutrophil leukocytosis
(True)
E Neutrophil pleocytois on CSF examination
(True)
Comments: Borrelia Burgdoferi (spirochete). Zoonosis (1xbdes deer tick) - Incubation 3-32 days. Early - Localised: annular rash (erythema migrans), fever, malaise, headach e. Disseminated: Haemotogenous spread, multiple small skin lesions, conjunctivitis, nodes, aseptic meningitis, seventh nerve palsy. Late - Arthritis waxing and waning over weeks (knee in 90%) worsens over time. Complications - Dehydrating, encephalitis, polyneuritis, impaired memory. Copyright © 2002 Dr Colin Melville
An 8 month old girl presents with fever and lethargy. The following are true: A The child can be safely discharged if only a maculopapular rash is found.
(False)
B The absence of a stiff neck, bulging fontanelle, and petechiae excludes meningococcal infection.
(False)
C A capillary refill time of 3 seconds means that oral fluids should be pushed.
(False)
D Petechiae in meningococcal septicaemia are characteristically found on the trunk.
(False)
E Meningitis caused by H. Influenzae group B can be excluded if the child has received 2 or more immunisations.
(False)
Comments:
30% of meningococcal disease presents initially with a maculopapular rash. Neck stiffness and bulging fontanelle are late signs. Petechiae are present in only 70% at presentation and may be found anywhere. (Henoch Schönlein Purpura petechiae are found on buttocks and extensor surfaces). A prolonged capillary refill time suggests increased circulating volume, and the need for IV fluids. Protection from Hib vaccine is around 99%, but invasive infections still occur. Copyright © 2002 Dr Colin Melville
The following mechanisms of microbial resistance are correctly ascribed: A Pseudomonas aeruginosa by mutation of specific binding proteins.
(False)
B Staphylococcus epidermidis by slime production.
(True)
C Staphylococcus aureus by slime production.
(False)
D Streptococcus faecalis by beta lactamase production.
(True)
E Herpes simplex by mutations of viral thymidine kinase.
(True)
Comments:
Pseudomonas produce inducible betalactamases and slime. Staphylococcus aureus produces betalactamases. Copyright © 2002 Dr Colin Melville
Causes of confusion and seizures in patients with AIDS include. A Toxoplasmosis.
(True)
B Progressive multifocal leuconencephalopathy.
(True)
C Cryptococcal meningitis.
(True)
D AIDS-dementia complex.
(True)
E CMV
(True)
Comments: PML is a progressive infection of oligodendroglial cells by JC papovirus in immune deficiency. Invariably fatal, but uncommon in children with HIV.Copyright © 2002 Dr Colin Melville
The following clinical features suggest that a febrile child of 9 months has a severe infection: A The presence of petechiae
(False)
B Rousability to pain
(True)
C Toe-core temperature difference of 4C
(True)
D Wetting of the nappy once a day
(True)
E Serum fibrinogen of 0.78g/L
(True)
Comments: Only 7% of children with fever and petechiae have a serious infection, but petechiae are characteristic of meningococcal disease, so 48 hours of antibiotics is reasonable until cultures are negative. Loss of consciousness is a late sign, su ggesting septic shock is affecting brain function. A high toe-core temperature difference sug gests poor perfusion. Oliguria suggest renal dysfunction. Normal fibrinogen level is 2-4g/l (1.253 in newborn). Low levels are found in disseminated intravascular coagulation. Copyright © 2002 Dr Colin Melville
Epstein-Barr virus is associated with: A Burkitt's lymphoma
(True)
B Cervical neoplasia
(False)
C nasopharyngeal carcinoma
(True)
D pharyngitis
(True)
E autoimminue haemolytic anaemia
(True)
Comments: a-Too easy. b-Seems a little vague. Is associated with lymphocytic lymphomas which could present in the neck and cervical lymphadenpopathy in infectious mononucleosis. c-Anaplastic nasopharyngeal carcinoma, common in SE China, virtually all cases have evidence of EB in the tumour tissue. d-Infectious mononucleosis. Usually severe pharyngitis. e-Usually resolves after 1-2 months.
The following should be avoided in suspected immunodeficiency: A MMR
(True)
B DPT
(False)
C Oral polio vaccine
(True)
D Pneumovax II vaccination
(False)
E Transfusion of packed cells
(True)
Comments: • • • • •
Live vaccines: MMR, oral polio, BCG, measles. Killed: pertussis. Inactivated: IM polio. Toxoids: DT. Submit: Hib.
Packed cells contain a few lymphocytes which can give transfusional graft versus host disease (GVHD) in SCID, which is invariably fatal. Viruses can also be transmitted via blood products. Copyright © 2002 Dr Colin Melville
The following micro-organisms are generally sensitive to Benzylpenicillin: A Streptococcus Pneumonaie
(True)
B Cryptococcus neoformans
(False)
C Bordetella pertussis
(False)
D Streptococcus viridans
(True)
E Mycoplasma pneumoniae
(False)
Comments:
Penicillin binds to specific penicillin-binding proteins (PBP's) in the cell wall, mainly of gram positive organisms. Penicillin resistance is usually due to production of altered PBPs or beta-lactamases which leave the penicillin molecule. Penicillin is mainly useful for Group A Strep., Group B Strep., meningococcal and pneumococcal infections, though and anthrax are also sensitive. Pneumococci with modified PBPs are an increasing problem. Copyright © 2002 Dr Colin Melville
In mumps A The incubation period is usually 21 da ys.
(False)
B Orchitis is typically bilateral.
(False)
C Aseptic meningitis is a complication.
(True)
D Amylase may be increased despite no evidence of pancreatitis clinically.
(True)
E Sublingual swelling may occur.
(True)
Comments: Paramyxovirus infect the salivary glands, especially the parotids. It is spread by direct contact, saliva, droplets, and urine. 85% of patients are <5 years to young adults. Fever, myalgia, headache, malaise, unilateral or bilateral parotid enlargement and pain, rarely a rash (MP). Complications include: meningoencephalomyelitis in >10% clinically or ? up to 65%. Orchitis affects 25% of adolescents. Bilaterally in 30%, only Æ fertility, not sterility. It rarely causes oophoritis, pancreatitis, nephritis, thyroiditis, myocarditis, mastitis, deafness (but important), ALSO, eye, joints and low platelets (3TP).Copyright © 2002 Dr Colin Melville
The following statements are true: A Brucellosis is characterised by neutrophil leucocytosis.
(False)
B Brucellosis is a recognised cause of spondylitis.
(True)
C Toxoplasmosis causes visceral larva migrans.
(False)
D Toxoplasmosis causes posterior uveitis.
(True)
E Serological evidence of toxoplasmosis is rare in adults.
(False)
Comments:
Brucellosis is a zoonosis, spreading from infected animals particularly cattle. There are 4 species, melitensis, abortus, suis, and canis. Pasteurisation of milk has decreased the incidence in the UK dramatically. Brucella are gram negative bacilli which are fastidious. There is usually a history of exposure, and the symptoms are rather nonspecific with fever, malaise, arthralgia and depression. 35% have hepatosplenomegaly. Leukopaenia is common, and 75% have a positive blood culture (90% of bone marrow cultures will be positive). Toxoplasma is most frequent in farming communities where contact occurs with cats, and patients eat raw meat. Clinical manifestations include: focal choroidoretinitis or posterior uveitis, optic atrophy, retinal detachment, cataract and glaucoma. Copyright © 2002 Dr Colin Melville
The following are true of tetanus: A failure to culture Clostridium tetani from the wound would make the diagnosis doubtful
(False)
B infection confers lifelong immunity
(False)
C there is a characteristic EEG
(False)
D Clostridium-specific intravenous immunoglobulin is of no benefit once spasm has started
(False)
E cephalic tetanus causes severe dysphagia
(True)
Comments: A-absence of a wound does not exclude tetanus. B-patients need to be actively immunized after recovery. C-The toxin tetanospasmin do esn't cross the blood brain barrier, it diffuses through the blood to bind to receptors containing gangliosides on the neuronal membranes of presynaptic nerve terminals in muscles. The toxin does reach the brain by axonal transport. D-it is ineffective once the toxin is attached to nervous tissue but may prevent progression. E-Cephalic meaning involving the cranial nerves usually from a wound on the head and neck. May be confused with rabies but hydrophobia never occurs. (OTM, 3e, 7.11.20)
Mediators of the febrile response include: A Interleukins
(True)
B Interferon
(True)
C Prostaglandins
(True)
D Endotoxins
(True)
E Monocytes
(True)
Comments:
The sequence of events is as follows: Exogenous pyrogen includes sources such as infection, immunological reactions or toxins. Endogenous pyrogens consist of cytokines such as IL1 and 6, TNFL,b and interferon-a. These are derived from monocytes, endothelial cells, B cells, glial cells and epithelial cells. Exogenous pyrogens cause a release of endogenous pyrogens which act on the hypothalamus which released prostaglandin E2. The latter a cts on the temperature regulatory centre to reset it, resulting in heat conservation by the body and increased heat production. Copyright © 2002 Dr Colin Melville
Circulating immune complexes are seen in: A Arthus reactions
(True)
B Post-streptococcal glomerulonephritis
(True)
C Late homograft rejection
(False)
D Serum sickness
(True)
E Rhesus incompatibility
(False)
Comments:
An arthus reaction is a type 3 serum sickness type reaction, while graft rejection is type 4 and rhesus reaction is type 2. Copyright © 2002 Dr Colin Melville
The following antimicrobial agents work in the way described: A Penicillin by binding to specific receptors to increase bact erial cell wall permeability.
(True)
B Acyclovir by specific inhibition of viral thymidine kinase.
(False)
C Erythromycin by inhibiting bacterial folate synthetase.
(False)
D Vancomycin by inhibiting bacterial ribosomes.
(False)
E Ciprofloxacin by inhibition of bacterial DNA gyrase.
(True)
Comments: Acyclovir is phosphorylated by viral thymidine kinase, which is triphosphorylated by cellular enzymes to inhibit the herpes simplex virus DNA po lymerase, thereby acting as a DNA chain terminator. Erythromycin inhibits bacterial ribosomes. Vancomycin inhibits cell wall synthesis by a mechanism that differs from betalactamases (no cross-resistance). Ciprofloxacin by inhibition of bacterial DNA gyrase Penicillin by binding to specific receptors to increase bacterial cell wall permeability.
Regarding the epidemiology of infections, the following statements are true: A Resistant vivax malaria is a major problem in Kenya.
(False)
B Diphtheria has been eradicated in most parts of the world.
(False)
C Polio has been eradicated in most parts of the world.
(True)
D Tetanus has been eradicated in most parts of the world.
(False)
E The AIDS epidemic seems to be declining worldwide.
(False)
Comments: Falciparum is the major resistance problem in sub-Saharan Africa (Kenya). Most vivax is Chloroquine sensitive, though resistant strains are appearing in New Guinea and Indonesia. Diphtheria is still prevalent in many parts of the world. An upsurge in polio is now nearing eradication. Tetanus is still common. AIDS is increasing inexorably.
Copyright © 2002 Dr Colin Melville
The following are characteristic of acute hepatitis B: A Most patients present with splenomegaly.
(False)
B It confers immunity to hepatitis A.
(False)
C It commonly presents with distal joint arthritis.
(False)
D There is increased infectivity in the presence of the E antigen.
(True)
E Pruritis is an important early symptom.
(False)
Comments: Clinical features of hepatitis B are as follows:
1. Most are asymptomatic. 2. Symptoms: Lethargy, anorexia, arthralgia, rash (any type), papu lar acrodermatitis (Gianotti Crosti), polyarthritis, glomerulonephritis, aplastic anaemia. 25 % have jaundice. 3. Complications: · Acute fulminent hepatitis. · Chronic hepatitis. · Membranous glomerulonephritis. Hepatitis E antigen is present in the acute phase and indicates a highly infectious state. Pruritis is characteristic of chronic hepatitis. Copyright © 2002 Dr Colin Melville
Herpes simplex: A Is a common cause of erythema multiforme.
(True)
B In the newborn is often fatal.
(True)
C Infection of genitalia is always due to type II.
(False)
D Primary infection is commonly followed by latent infection of sensory ganglion cells.
(True)
E May cause damage to the eyes.
(True)
Comments: Herpes simplex virus is a DNA enveloped virus which is extremely common. It causes infections of skin, mucus membranes, eyes, CNS, genitalia or systemic systems. The severity of disease is proportional to the degree of immuno-incompetence of the host. HSV1 affects the skin and mucus membranes above the waist. HSV2 generally affects the genitalia and the neonate. Incubation period is 202 days (7mo.), and is through close contact or skin breaks.
Clinical features: 1. 85% are asymptomatic. 2. Vesicular lesions causing a scab which heals over 700 days (2yr.), causing local pain but rarely scarring. 3. Primary mucus membrane involvement is manifest as gingivostomatitis, or occasional eczema hepeticum or keratoconjunctivitis. Secondary involvement usually results in cold sores or chronic keratoconjunctivitis. S ystemic infection usually occurs in the newborn or in immunocompromised patients such as those with cancer or HIV. CNS infection results in fever, changes in conscious level or personality with focal signs, and a p re?? For the temporal lobes. 4. Erythema multiforme is caused by hypersensitivity reaction to: Drugs: such as Penicillin, Sulphanomide, Isoniazid, Tetracycline, o Aspirin or Carbamazepine. Infections : such as EBV, herpes simplex virus 1 and 2, mycoplasma, o TB, Group A Strep. Other: Sunlight, leukaemia, lymphoma, HSP or Kawasaki Disease. o
A 3 year old boy presents with fever and headache. He has received oral Amoxycillin for 3 days. The following CSF findings exclude a partially treated meningitis: A Negative gram stain
(False)
B A CSF glucose of 45% of blood glucose
(False)
C A white cell count of 50
(True)
D A negative CSF culture
(False)
E Negative Kernig's Sign
(False)
Comments:
The assessment of children with suspected bacterial meningitis who have already received antibiotic therapy is a diagnostic conundr um. This applies to about 25-50% of children, so it is an important problem. Partial treatment may reduc e the incidence of positive CSF gram stains to <60%, and it also reduces the ability to grow the bacteria, particularly meningococcus. CSF glucose, protein, neutrophils and bacterial antigen testing or PCR should be completely unaffected.
Concerning CNS involvement in AIDS: A Toxoplasma may give rise to a focal lesion with neurological weakness.
(True)
B The HIV virus can be isolated from the brain of an encephalopathic patient. (True) C A diagnostic elevation in the CSF IgM occurs in toxoplasmic infection.
(False)
D Cerebral toxoplasmosis can be treated by Pyrimethamine alone.
(False)
E Occular involvement may cause blindness.
(True)
Comments:
Cerebral toxoplasmosis presents very variably, from an acute en cephalopathy to subtle neurological syndromes. It should be considered in all undiagnosed neurological disease in the under ones, especially if there are retinal lesions. Characteristic are hydrocephalus, seizures with focal defects, spinal or bulbar palsies, microcephaly, and decreased IQ. Investigations such as skull x-ray or CT scan show calcification of the periventricular area, tachyzoites in the C SF and positive blood titres. Pyrimethamine and Sulphadiazine have a synergistic effect in treating it, and folinic acid may be necessary to prevent seizures. Copyright © 2002 Dr Colin Melville
Giardia lamblia: A Is widespread in Europe.
(True)
B Is waterborne.
(True)
C Is a recognised cause of steatorrhoea.
(True)
D Is often asymptomatic.
(True)
E Is eradicated by Mebendazole.
(False)
Comments:
Giardia is a worldwide protozoa. It causes variable villus flattening on jejunal biopsy. The majority of cases are asymptomatic, though they may cause acute or chronic diarrhoea and a malabsorption syndrome. Symptoms are considerably worse in the immunosuppressed or immunodeficient. Metronidazole should be given if th e patients are symptomatic
Regarding diphtheria: A It is predominantly spread from cutaneous lesions.
(False)
B It is characterised by an inflammatory exudate forming a greyish membrane (False) on the buccal mucosa. C It produces a toxin which affects the myocardium, nervous and adrenal tissues.
(True)
D 3 doses of toxoid provides 75% protection.
(False)
E About 50 cases per year are seen in the UK.
(False)
Comments: Diphtheria is spread by droplets, through contact with soiled articles (fomites), and, in areas of poor hygiene, from cutaneous spread. The inflammatory exudate forms a greyish membrane on the tonsils and respiratory tract which may cause respiratory obstruction. Incubation is between 2 and 5 days, and patients may be infectious for 4 weeks. The toxin affects the myocardium, nervous and adrenal tissues. The immunisation has been tremendously successful, and most cases seen in the UK are imported from the Indian subcontinent or Africa. Recently, there has been a worrying epidemic of diphtheria in Russia and the newly independent states of the former Soviet Union. In 1995, 52,000 cases and 1,700 deaths were reported.
In HIV infected children: A Extrapulmonary pneumocytosis is recognised.
(True)
B CNS toxoplasmosis is recognised.
(True)
C Congenital CMV is common.
(False)
D Cytosporidial disease may be prolonged.
(True)
E Infectious mononucleosis may be fatal.
(False)
Comments: HIV infected children go through stages as their immunit y declines.
Stage 1: Increased frequency of common infections such as otitis media, sinusitis, chest infections, oral candida and pneumococcal and salmonella septicaemia.
Stage 2: Opportunistic infections including cryptosporidia (causing prolonged diarrhoea which can be very difficult to treat), pneumocysitis pneumonia, CMV (pneumonitis, hepatitis, retinopathy, and septicaemia), and CNS toxoplasmosis, in addition to candida oesophagitis and m ycobacterium aviumintracellularae infection (chronic weight loss). Congenital CMV occurs in about 1%, as in the normal population, though it may be more prevalent in patients from the developing world. It is certainly more symptomatic. Pneumocystis is very rarely seen outside the lung, but is recognised.
In meningococcal septicaemia: A Clinical features of meningitis are usually present
(False)
B Ciprofloxacin is a suitable choice for prophylaxis
(True)
C Prophylaxis does not reduce nasal carriage
(False)
D Treatment should await bacteriological confirmation
(False)
E A petechial rash is associated with DIC
(True)
Comments: Many patients with meningococcal septicaemia have no meningeal involvement. The mortality of meningococcal septicaemia is even higher than for meningitis. Prompt treatment is essential and all suspected cases must be given antibiotics without awaiting bacteriological confirmation. Ciprofloxacin and Rifampicin are the drugs most frequently used in chemoprophylaxis, the purpose of which is to eradicate nasopharyngeal carriage. The characteristic petechial rash is due to release of cytokines, prostaglandins and free radicals, which cause vasculitis and can lead to DIC and multi-organ failure.
Infection with Neisseria gonorrhoea may present with: A Arthritis B Phylyctenular conjunctivitis 6
(True) (False)
C Keratoderma blenorrhagica
(False)
D Proctitis
(True)
E Endocarditis
(True)
Comments:
Incubation is 1-4 days. In most cases it is as ymptomatic. Uncomplicated: Urethritis with purulent discharge and local inflammation. Ophthalmitis (child). Disseminated: (1-3%) after 7-30 days. Arthritis, dermatitis, carditis, meningitis, osteomyelitis. Complications: Pelvic inflammatory disease, hepatitis, septic abortion, concurrent STD. Keratoderma is associated with various congenital abnormalities. It consists of psoriasis-like plaques especially on the soles of the feet. Phlyctenular conjunctivitis can occur in TB and coccidioidomycosis and consists of small yellow lesions at the corneal ...
Chicken Pox: A has an incubation period of 5 - 7 days
(False)
B rash occurs in the mouth
(True)
C may develop in non-immune children who have been in contact with an adult with Herpes zoster infection
(True)
D maternal infection during the last 2 weeks of pregnancy is not harmful to the fetus
(False)
E the rash is preceeded by 4 - 5 days of prodromal illness
(True)
Comments: a - 10 - 21 days. b - And also at other mucosal sites such as the genitals. e - The prodrome is usually very short 1 - 2 days but can be up to 5 days in older children/adults - take your pick!
Regarding Group B Streptococcal infection in the newborn: A The risk of infection in the fetus increased following membrane rupture for greater than 18 hours.
(True)
B 95% of late infections are caused by type III.
(True)
C Symptomatic infection is usually mild.
(False)
D Purulent conjunctivitis is a common presentation of late disease.
(False)
E Clinical appearances may be indistinguishable from hyaline membrane disease.
(True)
Comments:
Symptomatic infection carries a 10-20% mortality, and complications include: meningitis and neurological sequelae; pneumothorax, persistent fetal circulation, and ARDS; arthritis and osteomyelitis. Conjunctivitis is rare. A 'ground glass' appearance is seen in 50% of Group B Strep. pneumonias, patchy pneumonia in 30%.
The following clinical signs may be associated with an underlying specific immunodeficiency:
A Eczema and petechiae
(True)
B Short limbs and abnormal hair
(True)
C Ataxia
(True)
D Truncus arteriosus
(True)
E Situs inversus
(False)
Comments:
The combination of eczema and petechiae suggests S Wiskott Aldrich Syndrome in a boy (X-linked recessive). Abnormal hair plus short limbs is found in S cartilage hair hypoplasia, and this is associated with combined T and B cell defects, sometimes severe. Situs inversus is associated with S Kartagener's Syndrome, a defect of ciliary function, which is therefore a defect of non-specific immunity. Ataxia is associated with ataxia telangiectasia, a DNA repair defect associated with variable immune defects, particularly IgA deficiency. A 2 month old boy presents with possible meningitis. If the CSF findings are as follows, the given interpretations are reasonable: A 20 white cells/mm3 - normal
(True)
B Glucose of 0.2mmol/L - TB meningitis
(True)
C 250 lymphocytes - bacterial meningits
(False)
D Protein of 2gm/L - viral meningitis
(False)
E CSF glucose of 67% of blood glucose - viral meningitis
(True)
Comments:
In the premature neonate, up to 25 mononuclear cells or 10 polymorphs may be seen in the CSF. In term newborns, up to 20 mononuclear cells or 10 polymorphs may be seen. In the neonatal period, up to 5 mononuclear cells or 10 polymorphs may be seen. Thereafter, more than 5 mononuclear cells should be considered abnormal. CSF protein levels are considerably higher in the premature or newborn infant, with levels upto 3g/L in the former and 1.2g/L in the latter. In older children, levels above 0.4g/L should be considered abnormal. CSF glucose levels are normally >50% of those in the blood. They are normal in viral meningitis, reduced in bacterial meningitis, and may be extremely low in TB meningitis. Copyright © 2002 Dr Colin Melville
Which of the following are true of osteomyelitis? A Is most commonly due to a staphylococcus aureus infection
(True)
B Can be due to salmonella infection in patients with sickle cell anaemia
(True)
C Infection usually involves the metaphysis of long bones
(True)
D Dead bone within the medullary canal is known as the involucrum
(False)
E New bone forming beneath the periosteum is known a the sequestrum
(False)
Comments: Osteomyelitis is usually due to staphylococcus aureus infection. Streptococcus pyogenes, Haemophilis influenza and gram-negative organisms can also infect bone. In children the infection is usually aquired b y haematogenous spread to the metaphysis of long bones. The dead bone within the medullary canal is the sequestrum. New subperiosteal bone formation is the involucrum.
The following are specific conditions with increased susceptibility to infection: A Noonan's Syndrome
(False)
B Right atrial isomerism
(True)
C Down's Syndrome
(True)
D Zinc deficiency
(True)
E Copper deficiency
(False)
Comments:
Right atrial isomerism is associated with asplenia. There is a high risk of infection with encapsulated bacteria. Howell Jolly bodies may b e seen on blood film. Down's Syndrome has a variety of immune defects and a high incidence of otitis media due to eustachian tube structure. With zinc deficiency there is a low lymphocyte function. Copyright © 2002 Dr Colin Melville
Renal damage is a recognised complication of infection with: A Plasmodium falciparum
(True)
B Schistosoma haematobium
(True)
C Plasmodium malariae
(True)
D Leptospira icterohaemorrhagica
(True)
E Mycobacterium leprae
(True)
Comments: c-Immune complex injury during chronic or repea ted infections. Pneumocystis pneumoniae
A Is an obligate intracellular organism.
(False)
B May be usefully diagnosed by serology.
(False)
C Can cause disease outside the respiratory system.
(True)
D Can have normal chest X-ray with prominent clini cal signs.
(False)
E Is adequately treated with Erythromycin alone.
(False)
Comments:
Pneumocystis is an obligate extracellular parasite with attributes of both fungi and protozoa. Most humans are seropositive by 4 years of age, though the transmission mode is unknown. 40% of children with HIV and 10% with leukaemia get PCP if no prophylaxis is given. Infection is almost always of the lungs, and rarely outside. The
onset is subtle, at a peak incidence of 3-6 months of age in HIV infected individuals, with a raised respiratory rate but no fever. There i s a gradual increase in respiratory distress and cyanosis with few clinical signs. Chest x-ray reveals marked c hanges of alveolitis, on some occasions looking like "post-neonatal h yaline membrane disease". Diagnosis is most effectively by bronchi-alveolar lavage or brushings are even better by lung biopsy. Treatment is high dose septrin and high dose steroids. Copyright © 2002 Dr Colin Melville
The following statements are true regarding microbiological specimens: A Blood cultures should be collected after the sterilisation of the skin with 2 alcohol wipes.
(False)
B A bag urine with 100 white cells and >105 E. Coli /ml confirms urinary tract infection in an infant.
(False)
C Bordetella pertussis can usually be grown from pernasal swabs of children with a classical whoop.
(False)
D The diagnosis of pulmonary tuberculosis in infants is best made with 3 successive early-morning gastric washings.
(True)
E Conjunctival scrapings may be helpful in diagnosing chlamydial eye infection in infants.
(True)
Comments:
For good quality blood cultures, iodine or Chlorhexidine should be used. At least 2 urine samples should be obtained (preferably including a catheter specimen or suprapubic aspirate) prior to commencing antibiotics. Bordetella culture is notoriously difficult, with true cultures 30-40%. Infants cough up and swallow their sputum. Conjunctival scrapings can be used for culture o r immunoflouresence and are the diagnosis method of choice. Remember to treat the accompanying (present in >50%) with oral Erythromycin. Copyright © 2002 Dr Colin Melville
Chronic granulomatous disease: A Is always inherited as an X-linked recessive condition.
(False)
B Is characterised by defective oxidative killing.
(True)
C Infections are characteristically caused by catalase-positive organisms.
(True)
D Abscesses in this condition contain no pus.
(False)
E The prognosis is excellent.
(False)
Comments:
There are multiple defects described of defects in n eutrophil oxidation but most are xlinked, but AR described. Catalase positive organisms (Staphylococcus aureus, Klebsiella, Candida, Aspergillus) cause recurrent pyogenic infections, abscesses and pneumonias. The LFA0CD11b)) is found on neutrophils and is necessary for them to leave the circulation. Thus, in LFA1-deficiency, no pus can be formed. Pus production is characteristic of chronic granulomatous disease (CGD). The morbidity in this condition is so high that bone marrow transplant may be considered. Copyright © 2002 Dr Colin Melville
Pyogenic meningitis A is commonly a result of meningococcal infection in the UK
(True)
B due to meningococcal infection is very rare in those aged less than 1 year old
(False)
C is associated with raised levels of IgM in the cerebrospinal fluid
(True)
D due to haemophilus influenzae is prone to run a subacute course in children, with the development of subdural effusion
(True)
E is complicated by cranial nerve lesions
(True)
Comments: Pyogenic meningitis is most commonly due to meningococcal infection. The disease occurs mostly in those aged 2 months to 20 with a peak incidence in the winter. IgM to Meningococcus is found in the CSF. Haemophilus influenzae on the other hand may run a more insidious course but is associated with more post-infective co-morbidity, deafness etc in particular VIII nerve deficits - deafness.
Concerning falciparum malaria: A The temperature pattern is quartan.
(False)
B Hypoglycaemia is a recognised consequence.
(True)
C Is likely to recur 5 years after leaving an endemic area.
(False)
D Corticosteroids are of no benefit in treating cerebral malaria.
(True)
E Primaquine is the treatment of choice in chloroqu ine-resistant areas.
(False)
Comments:
Falciparum produce a variable pattern of fever (subtertian or malignant tertian); Vivax and ovale produce benign tertian and quartan. Hypoglycaemia occurs, especially in infants. Recurrences of Vivax or ovale may recur weeks after apparently successful treatment (napatic cycle), but rarely after more than a year. In comatose stage of cerebral malaria, Dextran 70 may prevent intravascular coagulation . Convulsions need anti-convulsants. Quinine may be used in Chloroquine-resistance. Copyright © 2002 Dr Colin Melville
With regard to malaria: A Proguanil is recommended as prophylaxis for areas o f Chloroquine resistance.
(True)
B Congenital malaria can resemble neonatal sepsis.
(True)
C Primaquine should not be given to glucose-6-phosphate dehydrogenase deficient patients.
(True)
D Self treatment with Pyrimethamine-Sulfadoxine (Fansidar) is appropriate.
(False)
E Negative blood films exclude the diagnosis.
(False)
Comments:
Malaria results when red cells are invaded by any of the few species of plasmodia carried by the female Anopheles mosquito. Incubation is around 2 weeks, and the species of plasmodia are vivax, ovale, malariae and falciparum. Vivax and ovale cause 48 hourly fevers (benign tertian), and can recrudesce if treatment is inadequate. Malariae causes a quartan fever every 72 hours. Falciparum causes malignant tertian fever every 48 hours or so, but this less predictable. Congenital malaria is rare because of relative placental protection. Blackwater Fever is caused by falciparum malaria and severe haemolysis occurring in non-immune (usually Caucasian subjects). Nonimmune subjects have more serious illness and higher fevers. High tolerance occurs,
