Infection (viral Infection) Flashcards
AZT – zidovudine
Side effects?
Nausea
bone marrow suppression
myopathy
3TC – lamivudine
Side effects?
peripheral neuropathy
pancreatitis
There are five classes of antiretroviral drugs:
• Nucleoside (and nucleotide) reverse transcriptase inhibitors (NRTIs)
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
• Protease inhibitors
• Intergrase inhibitors
• CCR5 receptor blockers
HAART regim
💜children aged <2 years should be started on treatment regardless of CD4 count
💜children aged 2–5 years require treatment if CD4 count <25% or absolute count <750 cells/mm3
💜children aged >5 years with CD4 count <350 cells/mm3 require treatment
HIV encephalopathy
HIV encephalopathy
• May present with
🔺regression of milestones 🔺behavioural difficulties
🔺acquired microcephaly
🔺motor signs, e.g. spastic diplegia, ataxia, pseudobulbar palsy
• Exclude CNS infections and lymphoma
• Treatment: HAART
What causes infectious mononucleosis (glandular fever)?
EBV infects pharyngeal epithelial cells and then B lymphocytes
EBV stands for Epstein-Barr Virus.
How is infectious mononucleosis transmitted?
Saliva, aerosol
What is the incubation period for infectious mononucleosis?
30–50 days
List common clinical presentations of infectious mononucleosis.
- Fever
- Sore throat
- Lymphadenopathy
- Palatal petechiae
- Malaise
What is the incidence of hepatitis in infectious mononucleosis?
80%
What is the percentage of patients that experience clinical jaundice with infectious mononucleosis?
5%
What are some hematological complications associated with infectious mononucleosis?
- Thrombocytopenia
- Haemolytic anaemia
What percentage of patients of infectious mononucleosis develop a maculopapular rash when given ampicillin?
90%
What are key diagnostic features for infectious mononucleosis?
- Atypical lymphocytosis
- Positive Paul–Bunnell test or Monospot test (often negative in young children)
- Serology
- Heterophile antibodies
- PCR
What is the primary treatment approach for infectious mononucleosis?
Supportive care, steroids for severe inflammatory processes
CYTOMEGALOVIRUS in immunocompermized patient?
severe disease may occur with pneumonitis
retinitis
encephalitis
hepatitis and GI disturbance
How to diagnose CMV??
🔺immunofluorescence
🔺 intranuclear inclusions in biopsy specimens
culture
🔺detection of early antigen fluorescence foci (DEAFF) test
🔺PCR
What is most common congenital infection?
CMV
When should zidovudine (AZT, azidothymidine) be started for a baby?
Within 12 hours of birth
Zidovudine is used for the prevention of HIV transmission from mother to child.
How long should zidovudine treatment continue for the baby?
4 weeks
This treatment duration is crucial for reducing the risk of HIV infection.
What is the timing for the first HIV PCR test after birth?
24–48 hours
The PCR test helps in early detection of HIV in the newborn.
When should the second HIV PCR test be conducted?
6 weeks
This is also when Septrin prophylaxis should be started.
What should be done if all three HIV PCR tests are negative?
95% not infected
Stop Septrin
Follow HIV antibodies till they cleared
Fill in the blank: The third HIV PCR test should be repeated at _______.
3–4 months
This timing helps confirm the absence of HIV infection.
HIV Clinical stage 1
• Asymptomatic
• Persistent generalized lymphadenopathy
HIV Clinical stage 1
• Asymptomatic
• Persistent generalized lymphadenopathy
HIV Clinical stage 2
• Unexplained persistent hepatosplenomegaly
• Unexplained persistent parotid enlargement
• Papular pruritic eruptions
• Extensive wart virus infection
• Extensive molluscum contagiosum
• Herpes zoster
• Fungal nail infections
• Recurrent oral ulcerations
• Lineal gingival erythema
• Recurrent or chronic upper respiratory tract infections (otitis media, otorrhoea, sinusitis, tonsillitis)
What is prophylaxis for Herpis zoster ?
ZIG is given if high risk (e.g. immunodeficiency, immunosuppressive treatment)
ZIG helps prevent chickenpox in high-risk individuals.
When should a neonate receive zoster immunoglobulin (ZIG)?
If the mother develops chickenpox within 5 days before to 2 days after delivery
This is crucial to protect the neonate from chickenpox.
What treatment is administered if a baby develops chickenpox?
Intravenous aciclovir
Aciclovir is an antiviral medication used to treat infections caused by certain types of viruses.
What is the effect of zoster immunoglobulin (ZIG) on the incubation period in children?
The incubation period is extended to 28 days
This means that children who received ZIG may show symptoms of chickenpox later than usual.
Parvovirus B19
erythema infectiosum
slapped cheek
HHV-6
Roseola infantum
exanthem subitum
HHV-6
Roseola infantum
exanthem subitum
Roseola infantum
🔺sudden onset of high fever (up to 41°C) with absence of clinical localizing signs
🔺at days 3–4 fever abruptly stops and macular/papular rash appears which lasts from <24 h to a few days
🧶This is one of the most common causes of febrile convulsions in the 6- to 18-month age group
Red cells production in the embrue?
🔺In the human fetus clusters of stem cells (called blood islands) ➡️in the yolk sac ♂️3rd week
🔺these cells migrate to the liver ♂️ 3 months
🔺The bone marrow gradually takes over synthesis ♂️ 5 months and by birth almost all red cells are made in the bone marrow.
Causes of bone marrow failure
associated with a low reticulocyte count.
🔺marrow infiltration(e.g.acute lymphoblastic leukaemia or neuroblastoma)
🔺aplastic anaemia.
Aplastic anaemia causes?
The pluripotent stem cells are affected with reduction in all cell lines.
♂️About 20% are inherited, with Fanconi anaemia being the mostcommon Inherited aplastic anaemia.
♂️ acquired forms, many are
🔺 idiopathic
🔺viral infections (CMV, Non-A, non-B hepatitis, HIV, EBV),
🔺drugs (acetazolamide,chloramphenicol,chemotherapy)
🔺whole body irradiation.
Aplastic anaemia management
🔺supportivetreatment with blood and platelet transfusions and treatment of infections.
🔺 If an HLA-matched donor isavailable,bone marrow transplant is often the treatment of choice.
If a suitable donor is not available,
🔺immune suppression with antithymocyte globulin (ATG) and cyclosporin can be used.
What type of bone marrow failure Parvovirus B19?
🚀 erythroid progenitor cells🚀 resulting in isolated red cell aplasia.
Hereditary spherocytosis
The genetic abnormality results in defects in proteins of the red cell cytoskeleton. Spectrin defect is the most common abnormality but ankyrin, band 3 and band 4.2 defects are also known.
Spherocytes RBC
♂️spheroidal, less deformable
♂️ have a life span of only 28 days.
Spherocytes RBC
♂️spheroidal, less deformable
♂️ have a life span of only 28 days.
What are the types of infections in immunodeficiency?
Antibody : BVP
Cellular : BVPF
Neutrophils: BF
Complement : B
What are the causes of encephalitis?
is predominantly viral in origin.
Common viral causes include:
🕳️ Enteroviruses ❤️
🕳️Herpes simplex virus (HSV)-1 and HSV-2
🕳️Varicella-zoster virus
🕳️Measles
🕳️Mumps
🕳️ Influenza
Rare causes include:
• Adenoviruses, rubella virus, Epstein–Barr virus (EBV), arenaviruses (e.g. Japanese B encephalitis), rabies virus and Mycoplasma spp., West Nile virus
When the peak incidence of viral encephalitis??
is in the first 6 months of life with 1 or 2 cases per 1000 children.
peak incidence of viral encephalitis is in the first 6 months of life with 1 or 2 cases per 1000 children.
What is most common cause of bacterial meningitis??
Neisseria meningitidis
✔️ most cases being N. meningitidis B since the introduction of the conjugate meningococcal C vaccine.
Neisseria meningitidis is the most common cause of community-acquired bacterial meningitis in the UK, with most cases being N. meningitidis B since the introduction of the conjugate meningococcal C vaccine.
Specific contraindications to lumbar puncture include:
• Signs of raised intracranial pressure with changing level of consciousness, focal neurological signs or severe mental impairment
• Cardiovascular compromise with impaired peripheral perfusion or hypotension • Respiratory compromise with tachypnoea, an abnormal breathing pattern or hypoxia • Thrombocytopenia or a coagulopathy
bacterial meningitis, the CSF glucose level is usually low with a CSF:blood ratio <0.5, and the protein level is frequently raised to >0.4 g/l.
bacterial meningitis, the CSF glucose level is usually low with a CSF:blood ratio <0.5, and the protein level is frequently raised to >0.4 g/l.
The most common long-term complication of meningitis is sensorineural deafness. The overall rate of deafness after meningitis is less than 5%. Hearing impairment is higher in cases of pneumococcal meningitis than in meningococcal infections
Incubation period for varicella zoster?
10-21 days
2-3 weeks
What time for IG to peak and for how long
IgM= 7-10 d / few weeks
IgG= 4-6 w /for life
What function of IgD?
Signalling activation of B cell
Describe clinical manifestation in chickenpox?
1-2 d fever and malaise
Pruritic erythematous rash - vesciular rash
What are the types of infections in antibody difficiency?
🔹Bacterial : Staphylococcus😑 Streptocous 😑Haemophilus infleunze
🔹Viruses : Enteroviruses
🔹Protozoa: Giardia spp
What are the types of infection in cellular immunodeficiency??
🔹Bacteria :Mycobacterium spp 😑 Listeria spp.
🔹Virus : Cytomegalovirus(CMV)😐herpesvirus 😐Measles 😕RSV😔Adenoviruses
🔹Fungi : candida 😞aspergillus
🔹Protozoa: pneumocystis spp
How much it takes for hypothalmic - pituitary axis to recover after steroid administration??
full recovery of the HPA may take several months even
after cessation of treatment
What endocrine abnormalities after long term steroid use ??
🔹⬇️Cortisol
🔹⬇️ACTH
🔹⬇️CRH
What is the appropriate stress response for patients taking long term steroid??
®️ Standard practice is to double
or treble the current steroid dose. If no vomiting, it is appropriate to prescribe
the double steroid dose by the oral route . In the case of surgery, steroids may
be provided by an intravenous infusion.
®️ It is also important to pay close attention to hydration, electrolyte
balance and blood glucose
Hydronephrosis The main causes of hydronephrosis are as follows:
• VUR – see Section 12.1 • Pelviureteric junction (PUJ) obstruction • Usually detected on antenatal ultrasonography • Occasionally detected during investigation of UTI or abdominal pain • Main aspects of assessment are: • ultrasonography – degree of renal pelvic dilatation measured in the anteroposterior diameter: 5–10 mm mild; 11–15 mm moderate; >15 mm severe • MAG-3 renogram – findings that suggest significant obstruction are poor drainage despite furosemide given during scan and impaired function, e.g. <40% on hydronephrotic side • follow-up in the first 2 years after birth is based around ultrasonography every 4 months, withMAG-3 scan undertaken if hydronephrosis is severe initially, or progressively worsens over time
• surgical correction is by pyeloplasty • Usual when MAG-3 indicates obstruction and/or ultrasonography shows progressive increase in hydronephrosis • When dilatation is >30 mm, surgery is likely • Surgery is also considered if hydronephrosis is complicated by a proven UTI
• Vesicoureteric junction obstruction • Usually detected in the same ways as for PUJ obstruction • Ultrasonography shows renal pelvic and ureteric dilatation • Interventions include stenting the vesicoureteric junction (temporary measure) and surgical reimplantation
Hydronephrosis The main causes of hydronephrosis are as follows:
• VUR – see Section 12.1 • Pelviureteric junction (PUJ) obstruction • Usually detected on antenatal ultrasonography • Occasionally detected during investigation of UTI or abdominal pain • Main aspects of assessment are: • ultrasonography – degree of renal pelvic dilatation measured in the anteroposterior diameter: 5–10 mm mild; 11–15 mm moderate; >15 mm severe • MAG-3 renogram – findings that suggest significant obstruction are poor drainage despite furosemide given during scan and impaired function, e.g. <40% on hydronephrotic side • follow-up in the first 2 years after birth is based around ultrasonography every 4 months, withMAG-3 scan undertaken if hydronephrosis is severe initially, or progressively worsens over time
• surgical correction is by pyeloplasty • Usual when MAG-3 indicates obstruction and/or ultrasonography shows progressive increase in hydronephrosis • When dilatation is >30 mm, surgery is likely • Surgery is also considered if hydronephrosis is complicated by a proven UTI
• Vesicoureteric junction obstruction • Usually detected in the same ways as for PUJ obstruction • Ultrasonography shows renal pelvic and ureteric dilatation • Interventions include stenting the vesicoureteric junction (temporary measure) and surgical reimplantation
Duplex kidney
• Often detected on antenatal ultrasonography or during investigation of UTI • Two ureters drain from two separate pelvicalyceal systems; ureters sometimes join before common entry into the bladder, but more commonly have separate entries, with the upper pole ureter inserting below the lower pole ureter
• Common complications associated with duplex systems are: • Obstructed hydronephrotic upper moiety and ureter, often poorly functioning, associated with bladder ureterocele • Dilatation and swelling of submucosal portion of ureter just proximal to stenotic ureteric orifice can be seen within bladder on ultrasonography and as a filling defect on MCUG
• Ectopically inserted upper pole ureter, entering urethra or vagina; clue to this from history is true continual incontinence with no dry periods at all, as ectopic ureter bypasses bladder • VUR into lower pole ureter, sometimes causing infection and scarring of this pole
Multicystic dysplastic kidney
• Irregular cysts of variable size from small to several centimetres; no normal parenchyma • Dysplastic atretic ureter • No function on MAG-3 or DMSA scan • Commonly involute over time • No indication for routine surgical removal • Follow-up with ultrasonography at 3 months, then 12 months, 2 years and 5 years
• At the 5-year visit, if ultrasonography shows normal contralateral kidney with compensatory hypertrophy of this kidney, and the child has a normal BP, no proteinuria and normal plasma creatinine, then reasonable to discharge from long-term hospital follow-up • 20–40% incidence of VUR into contralateral normal kidney
Horseshoe kidney
• Two renal segments fused across midline at lower poles in 95%, upper poles in 5% • Isthmus usually lies low, at the level of the fourth lumbar vertebra immediately below the origin of the inferior mesenteric artery
• Associations include Turner syndrome, Laurence–Moon–Biedl syndrome • Usually asymptomatic but increased incidence of PUJ obstruction and VUR, so may develop a UTI
Hypospadias
• Opening of urethral meatus is on the ventral surface of penis, at any point from the glans to base of penis or even perineum
• Meatus may be stenotic and require meatotomy as initial intervention • Foreskin is absent ventrally; it is used in surgical reconstruction of a deficient urethra so circumcision should not be performed
• Usual best age for surgical correction is around 12 months • Chordee is the associated ventral curvature of the penis, seen especially during erection, and this also requires surgical correction; caused by fibrous tissue distal to the meatus along the ventral surface of penis
Impalpable testes
• May be intra-abdominal, inguinal or pre-scrotal • Main aim of diagnosis and management is: • to preserve fertility • to reduce risk of malignancy and to enable early detection of malignant change if it occurs
• Infants should be referred to paediatric surgeon or urologist by age 6 months • Ultrasonography may detect inguinal testis, but is of limited use for intra-abdominal testis; MRI may be better, but usually requires general anaesthetic for infant; laparoscopy may be final method for localising testis
• Surgical orchidopexy has 95% success rate; hormonal therapy with human chorionic gonadotrophin (hCG) <15% success and so surgery is preferred option
• Optimum age for surgery is 9–12 months; usually combined with repair of the associated inguinal hernia; may require two-stage procedure for intra-abdominal testis
Impalpable testes
• May be intra-abdominal, inguinal or pre-scrotal • Main aim of diagnosis and management is: • to preserve fertility • to reduce risk of malignancy and to enable early detection of malignant change if it occurs
• Infants should be referred to paediatric surgeon or urologist by age 6 months • Ultrasonography may detect inguinal testis, but is of limited use for intra-abdominal testis; MRI may be better, but usually requires general anaesthetic for infant; laparoscopy may be final method for localising testis
• Surgical orchidopexy has 95% success rate; hormonal therapy with human chorionic gonadotrophin (hCG) <15% success and so surgery is preferred option
• Optimum age for surgery is 9–12 months; usually combined with repair of the associated inguinal hernia; may require two-stage procedure for intra-abdominal testis
Boys presenting with scrotal pain will often need to be assessed by a paediatric surgeon • History and examination are the most important components of assessment • Ultrasonography with colour Doppler to assess testicular blood flow may contribute • Torsion of testicle: • Acute abrupt onset of often severe pain • Early puberty • Swelling of testis and hemiscrotum, often with erythema/discoloration of scrotal skin • Diffuse tenderness of testis • Negative urinalysis • Treatment is surgical exploration
• Torsion of appendix of epididymis: • More common than torsion of testicle • Subacute onset of pain over hours • Pre-pubertal • Tenderness localized to the upper pole of testis • Negative urinalysis • If confident of diagnosis may be managed conservatively; however, may be difficult to distinguish from torsion of testicle so may require surgical exploration
• Epididymitis: • Gradual insidious onset of discomfort or pain • Adolescence • Epididymal tenderness • Urinalysis often positive (although may be negative) • May have low-grade fever; raised C-reactive protein (CRP) • Treatment with antibiotics (e.g. co-amoxiclav, cefalexin) if urinalysis suggestive of infection
• Trauma: • History usually informative • Trauma may cause a haematocele or testicular haematoma
• Hernia or hydrocele: • Not usually acutely painful • Swelling in scrotum, extending into inguinal canal if hernia • No erythema or discoloration of overlying scrotal skin • Hydrocele will transilluminate with pen torch
Bladder extrophy and epispadias
• Rare disorder; more common in boys • Bladder mucosa is exposed (and with exposure and infection becomes friable), bladder muscle becomes fibrotic and non-compliant
• Anus anteriorly displaced • Boys – penis has epispadias (dorsal opening urethra) and dorsal groove on glans, with dorsal chordee and upturning; scrotum is shallow and testes are often undescended • Girls – female epispadias with bifid clitoris, widely separated labia• Pubic bones separated • Requires surgical reconstruction; long-term urinary incontinence is common
ACID–BASE, FLUID AND ELECTROLYTES 6.1 Metabolic acidosis A primary decrease in plasma bicarbonate and a decrease in plasma pH as a result of:
• Bicarbonate loss, e.g. • Gastrointestinal loss in severe diarrhoea • Renal loss in proximal (type 2) renal tubular acidosis (RTA)
• Reduced hydrogen ion excretion, e.g. • Distal (type 1) RTA • Acute and chronic renal failure
• Increased hydrogen ion load, e.g. • ↑ endogenous load: • inborn errors of metabolism, e.g. maple syrup urine disease, propionic acidaemia • lactic acidosis, e.g. cardiovascular shock • ketoacidosis, e.g. diabetic ketoacidosis (DKA) • ↑ exogenous load, e.g. salicylate poisoning
Anion gap
• A classification of metabolic acidosis involves assessing the anion gap – the ‘gap’ between anions and cations made up by unmeasured anions, e.g. ketoacids, lactic acid
• Measured as [Na+ + K+] – [HCO3 – + Cl–]; thus normal anion gap is [140 + 4] – [24 + 100] = 20
• Acidosis may be a normal anion gap, when Cl– will be raised, i.e. hyperchloraemic • May be an increased anion gap, when Cl– will be normal, i.e. normochloraemic
Examples:
• Normal anion gap, hyperchloraemia, acidosis – RTA • Na+ 140, K+ 4, Cl– 110, HCO3
– 14, anion gap = 20
• Increased anion gap, normochloraemia, acidosis – DKA • Na+ 140, K+ 4, Cl– 100, HCO3
– 15, anion gap = 30
