Differentials
Common
Viral syndromes
History
chills, headache, rhinorrhoea, sore throat, cough, nausea, vomiting, abdominal pain, myalgia, rash
Exam
generally normal except for non-specific rash
1st investigation
- no initial test for most viruses:
clinical diagnosis
More
Other investigations
Urinary tract infection
History
nausea, vomiting, dysuria, urinary frequency, abdominal or back pain, recent urinary incontinence, fever >24 hours, history of previous UTIs, non-black racial background
Exam
ill appearance, suprapubic or flank tenderness
1st investigation
- urine dipstick:
positive for leukocyte esterase or nitrites
More - urine microscopy:
≥5 WBC/HPF or any bacteria
More - enhanced urinalysis:
≥10 WBC/mm³ or any bacteria on Gram stain
More - urine culture:
>100,000 colony forming units (CFU)/mL from clean-catch specimen; >10,000 CFU/mL from catheterised specimen; >1000 CFU/mL from suprapubic aspiration specimen
Other investigations
- procalcitonin:
may be elevated
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Pneumonia
Coronavirus disease 2019 (COVID-19)
History
typically asymptomatic or mild symptoms: brief and rapidly resolving fever, mild cough, sore throat, congestion, rhinorrhoea; moderate to severe illness can occur in children
Exam
fever and coryzal symptoms; may be inspiratory crackles, rales, and/or bronchial breathing in patients with pneumonia or respiratory distress.; patients with respiratory distress may have tachycardia, tachypnoea, or cyanosis accompanying hypoxia
1st investigation
Other investigations
Bronchiolitis
History
primarily a disease of infancy (rare in children age >1 year); usually starts with upper respiratory tract symptoms (e.g., rhinitis and cough); low-grade fever; increased severity of cough, wheeze, and laboured breathing
Exam
tachypnoea, retractions, wheezes, crackles; sometimes thoracoabdominal asynchrony; fever <40°C (<104°F); retractions, grunting, and nasal flaring
1st investigation
- no initial test:
clinical diagnosis
Acute otitis media
History
fever, pain, muffled sounds, post-auricular swelling if mastoid is involved, sleep disturbance, headache, diarrhoea, irritability in infants, poor appetite
Exam
bulging, erythematous, or opaque tympanic membrane
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Tonsillitis
History
sore throat, painful swallowing, headache, fever, chills, abdominal pain, nausea and vomiting, cough, rhinorrhoea
Exam
tonsillar erythema and enlargement, and enlarged tender cervical lymphadenopathy; purulent exudate may be present, especially if caused by group A beta-haemolytic streptococci
1st investigation
Other investigations
- serological testing for streptococci:
considered positive if there is a four-fold rise in antibody titres
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Rhinosinusitis
History
rhinorrhoea, nasal congestion, cough (frequently worse at night); symptoms lasting >10-14 days suggests bacterial (as opposed to viral) aetiology
Exam
nasal drainage, cough, sinus tenderness, periorbital swelling
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Meningitis
History
irritability, lethargy, seizures (focal seizures raise the concern for herpes meningoencephalitis), poor feeding, paradoxical irritability (cries more when held), nausea or vomiting, headache, neck pain, photophobia, back pain
Exam
pyrexia (or hypothermia), bulging fontanelle, papilloedema, meningismus, Kernig's and/or Brudzinski's sign may be positive although not commonly seen in infants, focal neurological deficits
1st investigation
- cerebrospinal fluid (CSF) cell count:
>22 WBC/microlitre in term infant; >7 WBC/microlitre in older child
More - CSF Gram stain and culture:
identifies pathogen
More - CSF protein and glucose:
CSF protein ≥80 mg/dL; CSF glucose <50% of serum glucose
More - serum polymerase chain reaction (PCR) for Neisseria meningitidis:
molecular confirmation of specific pathogen
More
Other investigations
- procalcitonin:
may be elevated
More - CSF PCR for N meningitidis and Streptococcus pneumoniae:
N meningitidis or S pneumoniae DNA
Bacteraemia (occult)
History
fever may be only symptom; malaise
Exam
may be normal examination apart from fever; important to evaluate for possible signs of sepsis (e.g., tachycardia, increased respiratory rate, behaviour change, delayed capillary return, rash)
1st investigation
Other investigations
- procalcitonin:
may be elevated
More
Sepsis
History
may present with non-specific, non-localised symptoms (especially in younger children); fever, low body temperature or temperature instability; altered mental state or behaviour (e.g., drowsiness, delirium, lethargy, irritability, non-responsiveness, or apnoeas); may be history of risk factors (e.g., immunosuppression, and comorbidities); healthcare associated factors (e.g., indwelling vascular catheters, recent invasive procedures); in neonates, history of premature rupture of membranes, chorioamnionitis, or intrapartum maternal fever may be present; may present with circulatory shock; poor feeding, or emesis
Exam
tachycardia, tachypnoea, fever >38℃ (>100.4°F) or hypothermia <36℃ (<96.8°F); infants and young children may be hypotonic with normal or poor peripheral perfusion and hypotension; prolonged capillary refill, mottled or ashen skin, cyanosis, low oxygen saturation, reduced urine output; may be absence of bowel sounds; hypo- or hyperglycaemia may be present
1st investigation
- blood culture:
may be positive for organism
More - serum lactate:
may be elevated
More - FBC with differential:
abnormal WBC count (i.e., above or below normal range for age or >10% immature white cells); low platelets
More - CRP:
elevated
- blood urea and serum electrolytes:
serum electrolytes may be deranged; blood urea may be elevated
- serum creatinine:
may be elevated
More - LFTs:
may show elevated bilirubin, alanine aminotransferase, aspartate aminotransferase
- coagulation studies:
may be abnormal
- blood gases:
may be hypoxaemia, hypercapnia, elevated anion gap, metabolic acidosis
Other investigations
- CXR:
may show consolidation; demonstrates position of central venous catheter and tracheal tube
- urine microscopy and culture:
may be positive for nitrites, protein or blood; elevated leukocyte count; positive culture for organism
- lumbar puncture:
presence of organism on microscopy and positive culture
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Septic arthritis
History
irritability, decreased joint mobility, limpness, inability to bear weight
Exam
joint swelling, redness, painful range of motion
1st investigation
Osteomyelitis
History
irritability, pain, refusal to move extremity, limpness
Exam
limb tenderness, erythema
1st investigation
Other investigations
- MRI limb:
bone or soft-tissue involvement
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Cat-scratch disease
History
exposure to cats (especially young cats), fever, blurred vision, confusion, arthralgia, myalgia
Exam
cutaneous lesion at site of inoculation, regional lymphadenopathy, hepatosplenomegaly, conjunctivitis, pre-auricular lymphadenopathy, retinitis, encephalopathy
1st investigation
- serology:
positive for Bartonella henselae
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Infectious mononucleosis
History
sore throat, malaise, rash, jaundice, myalgias
Exam
rash, icterus, generalised (particularly posterior cervical) lymphadenopathy, hepatomegaly, splenomegaly, periorbital oedema, palatal petechiae
1st investigation
Other investigations
- Epstein-Barr antibodies:
positive
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Cytomegalovirus infection
History
fatigue, pharyngitis, nausea, vomiting, diarrhoea, malaise, rash, headache
Exam
hepatomegaly, splenomegaly, lymphadenopathy
1st investigation
- serology:
CMV-IgM titre is indicative of acute infection; CMV-IgG titre suggests past infection; antibody avidity is low in recent infection
- nucleic acid detection:
positive
More
Other investigations
Malaria infection
History
fever on alternate days (or every third day with Plasmodium malariae), chills, headache, myalgia, cough, nausea, abdominal pain, history of recent travel abroad
Exam
high-grade pyrexia, splenomegaly, confusion
1st investigation
- peripheral blood smear:
visible parasitaemia on microscopy
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Other investigations
- serology:
positive
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Lyme disease
History
headache, myalgia, fatigue, arthralgias, stiff neck, history of a tick bite
Exam
erythema migrans (EM), meningismus, signs of carditis or myopericarditis, radiculoneuropathy, facial nerve palsy
1st investigation
- no initial test:
clinical diagnosis
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Other investigations
- serological testing:
positive for Borrelia burgdorferi
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Tuberculosis
History
night fever, sweating, cough, haemoptysis, poor appetite, weight loss, headache, history of recent travel abroad or contact with a person with the disease
Exam
lymphadenopathy, wheezing, abnormal breath sounds; altered mental status, seizures, focal neurological deficits; hepatomegaly, splenomegaly in severe cases; arthritis
1st investigation
- CXR:
may demonstrate atelectasis from airway compression, pleural effusion, consolidation, pulmonary infiltrates, mediastinal or hilar lymphadenopathy, upper zone fibrosis.
More - sputum, gastric aspirate or bronchoalveolar lavage acid-fast bacilli smear and culture:
presence of acid-fast bacilli (Ziehl-Neelsen stain) in specimen
More - acid-fast bacilli smear and culture of extrapulmonary biopsy specimen:
positive
More - nucleic acid amplification tests (NAAT):
positive for M tuberculosis
More
Other investigations
- lateral flow urine lipoarabinomannan (LF-LAM) assay:
positive
More
Kawasaki disease
History
fever, arthralgias, abdominal pain, irritability
Exam
changes in extremities (acute erythema of palms or soles, or oedema of hands and feet; periungual peeling of digits); polymorphous exanthema; bilateral bulbar conjunctival injection without exudates; changes in lips and oral cavity (erythema, cracked lips, strawberry tongue, diffuse injection of oral and pharyngeal mucosa); cervical lymphadenopathy (>1.5 cm diameter), usually unilateral
1st investigation
Juvenile idiopathic arthritis (JIA)
History
pain in ≥1 joint lasting ≥6 weeks (pauciarticular arthritis involves ≤4 joints, polyarticular disease involves ≥5 joints); low-grade fever usually of longer duration (e.g., 2 weeks); morning stiffness; myalgias
Exam
joint swelling, warmth, tenderness; certain subtypes of JIA preferentially involve larger joints, iridocyclitis
1st investigation
Other investigations
Systemic lupus erythematosus
History
malar rash, arthralgias, malaise, chest pain, seizures, photosensitivity, psychosis
Exam
weight loss, hypertension, oedema, hepatomegaly, splenomegaly, lymphadenopathy, arthritis, cranial nerve abnormalities, malar rash, discoid rash, oral ulcer, arthritis, serositis (pleuritis or pericarditis)
1st investigation
Other investigations
Rheumatic fever
History
prolonged fever, history of sore throat, joint pains, rash, chest pain, dyspnoea, involuntary movements
Exam
arthritis (typically migratory and involving large joints), subcutaneous nodules (typically firm and painless), erythema marginatum (fleeting pink rash typically involving trunk and proximal arms and legs), murmur, pericardial rub, Sydenham's chorea
1st investigation
Other investigations
- echocardiography:
evidence of carditis, valvular defects
Crohn's disease
History
nausea, vomiting, diarrhoea (sometimes bloody), abdominal pain, weight loss, arthralgia
Exam
pallor, abdominal distension and tenderness, arthritis, anal involvement and oral lesions, erythema nodosum, uveitis
1st investigation
Ulcerative colitis
History
nausea, vomiting, diarrhoea (sometimes bloody), abdominal pain, weight loss, joint pains
Exam
pallor, abdominal distension and tenderness, skin rashes, arthritis, lack of anal involvement
1st investigation
Other investigations
- endoscopy:
inflammatory lesions generally restricted to the mucosa of the colon and rectum
Leukaemia
History
weight loss, poor appetite, petechiae, fatigue, pallor, bone pains, easy bruising, headache[9]
Exam
petechiae or purpura, testicular pain, lymphadenopathy, hepatomegaly, splenomegaly
1st investigation
- FBC with peripheral smear:
abnormally low or high WBC count, anaemia, thrombocytopenia; abnormal cells on peripheral smear
- CXR:
mediastinal mass
- lactate dehydrogenase:
elevated
More
Other investigations
- bone marrow biopsy:
bone marrow hypercellularity and infiltration by leukaemic lymphoblasts; ≥20% lymphoblasts in the bone marrow; negative myeloperoxidase stain
Non-Hodgkin's lymphoma
History
night sweats, poor appetite, weight loss, dyspnoea, cough, generalised pruritus
Exam
lymphadenopathy, hepatomegaly, splenomegaly, jaw or orbital mass
1st investigation
- FBC with peripheral smear:
abnormally low or high WBC count, anaemia, thrombocytopenia; abnormal cells on peripheral smear
- CXR:
mediastinal mass
- lactate dehydrogenase:
elevated
More
Other investigations
- bone marrow/lymph node biopsy:
malignant cells
Drug-related fever
History
history of new medications and/or a change in dosage, seizures, altered mental status
Exam
tachycardia; tachypnoea; hypertension; mydriasis; hot, flushed, dry skin (e.g., anticholinergics); diaphoresis (e.g., cocaine, amphetamines)
1st investigation
- no initial test:
clinical diagnosis
Vaccine reaction
History
history of vaccinations, injection site pain, agitation, pruritus, vomiting, headache
Exam
injection site hypersensitivity, oedema, local mass; urticarial rash; myalgia; vasodilatation
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Scarlet fever
History
scarlatiniform rash, fever, sore throat, headache, nausea and vomiting, abdominal pain, skin or soft tissue infection including impetigo, surgical wound infection, absence of cough or other viral symptoms; scarlatiniform rash may present prior to or independent of symptoms of pharyngitis, especially in children <5 years
Exam
scarlatiniform rash: diffuse, finely papular (sandpaper-like), erythematous rash that blanches with pressure, accentuated in flexor creases producing red streaks known as Pastia's lines, flushed 'scarlet' bilateral cheeks with circumoral pallor, in patients with darker skin, may appear as though sunburnt; inflamed tongue with a white coating and prominent papillae ('strawberry tongue'); tonsillopharyngeal inflammation, patchy tonsillopharyngeal exudates, palatal petechiae, tender and enlarged anterior cervical lymph nodes; skin desquamation is a late finding (3 to 4 days after scarlatiniform rash); pyoderma
1st investigation
- clinical diagnosis:
diagnosis is mainly clinical
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Uncommon
Typhoid (enteric fever)
History
malaise, vomiting, headache, abdominal pain, diarrhoea, cough, history of recent travel abroad, exposure to contaminated food products (commonly poultry and eggs)
Exam
bradycardia, rose spots (maculopapular rash typically on trunk and abdomen), hepatomegaly, splenomegaly
1st investigation
Infective endocarditis
History
fever, malaise, symptoms due to septic emboli (e.g., stroke)
Exam
heart murmur, Janeway lesion (painless maculopapular lesions on palms and soles), Osler nodes (painful nodules on tips of fingers), Roth spots (haemorrhagic retinal lesions)
1st investigation
- blood culture:
bacterial growth (commonly Staphylococcus aureus, Enterococcus,Streptococcus bovis, Streptococcus viridans), HACEK (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella species) organisms
More - echocardiography:
detection of vegetations, valvular dysfunction, perivalvular extension.
Other investigations
Liver abscess
History
malaise, nausea, vomiting, jaundice, right upper quadrant abdominal pain, chest pain (may be confused with chest infection), poor appetite
Exam
icterus, hepatomegaly, right upper quadrant abdominal pain, hepatic mass, weight loss
1st investigation
Other investigations
Brain abscess
History
irritability, lethargy, seizures, poor feeding, paradoxical irritability (cries more when held), nausea or vomiting, headache
Exam
pyrexia or hypothermia, focal neurological deficits, bulging fontanelle, papilloedema
1st investigation
Other investigations
Streptococcal toxic shock syndrome
History
high-grade fever, confusion, malaise, rash, diarrhoea, vomiting, respiratory distress, recent/current chickenpox
Exam
hypotension (<5th percentile for age for children <16 years of age), signs of pneumonia, jaundice, signs of prerenal failure, bleeding (due to coagulopathy), generalised rash that may desquamate, soft-tissue necrosis including necrotising fasciitis, myositis, or gangrene
1st investigation
- serum creatinine:
elevated ≥2 times upper limit of normal for age
More - platelet count:
<100,000/microlitre
More - LFT:
elevated ≥2 times upper limit of normal for age (aspartate aminotransferase, alanine aminotransferase, bilirubin)
More - blood, cerebrospinal fluid (CSF), or aspirate culture:
isolation of group A Streptococcus
More
Other investigations
- CXR:
diffuse pulmonary infiltrates
More
Staphylococcal toxic shock syndrome
History
high-grade fever, confusion, malaise, rash, diarrhoea, vomiting, severe myalgia, disorientation or alterations in consciousness, menstruation and tampon use, distal limb injury especially paronychia or burn
Exam
hypotension (<5 percentile by age for children <16 years of age); orthostatic drop in diastolic BP ≥15 mmHg), orthostatic syncope or dizziness, diffuse macular erythroderma with desquamation 1-2 weeks after onset of illness particularly involving palms and soles; mucous membrane (vagina, oropharyngeal, or conjunctival) hyperaemia
1st investigation
- creatine kinase:
elevated >2 times normal limit
- blood urea nitrogen or serum creatinine:
>2 times normal upper limit
- platelet count:
<100,000/microlitre
- blood, throat, or cerebrospinal fluid culture:
no growth of pathogen
More
Other investigations
- Staphylococcus aureus antibody testing:
presence of S aureus in the absence of an acute-phase antibody
Tularaemia
History
ulceroglandular form: lymphadenopathy with (papule or ulcer developing into eschar at skin lesion of inoculation) or without skin changes, sore throat, abdominal pain, vomiting, diarrhoea, cough, shortness of breath; typhoid form: fever but no skin or lymph node involvement; chills, headache, anorexia, myalgias
Exam
hepatosplenomegaly, lymphadenopathy, conjunctivitis, skin lesion, exudative pharyngitis, abdominal tenderness, rales
1st investigation
- tube agglutination:
elevated titre >1:160, or 4-fold increase in acute and convalescent titres
More
Other investigations
- body fluid culture:
positive for Francisella tularensis
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Brucellosis
History
malaise, fatigue, depression, recent travel, exposure to animals or animal products (especially of unpasteurised cheese), lethargy, orthopaedic complaints, scrotal pain, abdominal pain, headache, arthralgia, weight loss
Exam
scrotal or abdominal tenderness, hepatosplenomegaly
1st investigation
- serum agglutination:
positive titres >1:160
- enzyme-linked immunosorbent assay:
positive
More
Other investigations
- blood culture:
positive growth
More
Leptospirosis
History
exposure to environmental sources (e.g., animal waste, contaminated soil or water), myalgias, rigors, headache, cough, nausea, vomiting, diarrhoea, abdominal pain
Exam
conjunctival suffusion, uveitis, evidence of haemorrhage, hepatosplenomegaly, muscle tenderness
1st investigation
- blood, cerebrospinal fluid, or urine culture:
positive for growth of Leptospira
More - enzyme-linked immunosorbent assay:
positive for Leptospira
Other investigations
- microscopic agglutination test:
positive for Leptospira
More
Encephalitis
History
headache, seizures, altered mental status
Exam
non-specific rash, focal neurological deficits, meningismus
1st investigation
Other investigations
Myocarditis
History
rhinorrhoea, cough, chest pain, palpitations, dyspnoea, orthopnoea, syncope, fatigue, vomiting, diarrhoea, abdominal pain, myalgias, poor feeding; history of travel to endemic areas may suggest a specific infectious aetiology; history of autoimmune disease or exposure to possible toxic substances or drug
Exam
tachypnoea, hypotension, rales, elevated neck veins, S3 gallop, S3 and S4 summation gallop, pericardial friction rub, murmur, peripheral hypoperfusion, sinus tachycardia, atrial and ventricular arrhythmias, hepatomegaly, altered sensorium
1st investigation
- ECG:
most commonly displays sinus tachycardia or non-specific ST-segment and T-wave abnormalities; low voltages; axis deviation
- echocardiography:
global and regional left ventricular motion abnormalities and dilatation, valvular regurgitation, reduced ejection/shortening fraction, ventricular hypertrophy, heart block
- cardiac enzymes:
elevated
More
Other investigations
- endomyocardial biopsy (EMB):
histopathological findings of myocardial cellular infiltrates ± myocardial necrosis
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Herpes simplex virus (HSV) infection
History
neonates: maternal fever at time of delivery, presentation within the first month of life, 3 manifestations (disseminated disease, CNS involvement, skin/eyes/mucous membrane involvement), most neonates have skin manifestations such as grouped vesicles, lethargy, and poor feeding with disseminated disease or CNS involvement; older children: may have encephalitis with alteration in mental status, personality changes, and seizures (commonly focal)
Exam
neonates: fever or temperature instability with hypothermia, vesicles on skin/eyes/mouth, respiratory distress and jaundice with disseminated disease, neurological signs with CNS involvement; older children: focal neurological findings with encephalitis
Other investigations
- glycoprotein G-based type-specific serology (gG1 and gG2):
positive antibody to HSV-1 or HSV-2
More
Human immunodeficiency virus (HIV) infection
History
perinatal acquisition: primary acute infection generally asymptomatic; adolescents: primary acute infection presents with fever, fatigue, and malaise
Exam
primary acute infection in adolescents: fever, adenopathy, hepatosplenomegaly, rash
Toxoplasmosis
History
malaise, rash, confusion, arthralgias, immunocompromised patient, exposure to cat faeces
Exam
altered mental state, seizures, focal neurological deficits, cervical or supraclavicular lymphadenopathy (especially bilateral, symmetrical, non-tender)
1st investigation
- serological testing:
positive IgG and IgM antibodies
More
Other investigations
Rocky Mountain spotted fever
History
headache, confusion, malaise, nausea, vomiting, myalgia, abdominal pain, diarrhoea, history of a tick bite
Exam
rash (commonly petechial and involving palms and soles, but may be maculopapular only), conjunctivitis, altered mental status, lymphadenopathy, peripheral oedema, hepatomegaly
1st investigation
- serology:
positive for detection of rickettsial antibodies
More
Other investigations
- skin biopsy:
rickettsiae found via immunostaining of tissue specimens
More
Sarcoidosis
History
cough, fatigue, arthralgias, wheezing, photophobia, red eye, blurred vision, weight loss, headache
Exam
weight loss, lymphadenopathy, erythema nodosum, uveitis
1st investigation
- CXR:
hilar lymphadenopathy
Other investigations
- skin or lymph node biopsy:
non-caseating epithelioid granuloma
Hodgkin's lymphoma
History
night sweats, poor appetite, weight loss, dyspnoea, cough, generalised pruritus
Exam
lymphadenopathy, hepatomegaly, splenomegaly
1st investigation
- FBC with differential:
abnormally low or high WBC count, anaemia, thrombocytopenia
- CXR:
mediastinal mass
- excisional lymph node biopsy or core biopsy:
Hodgkin's cells within an appropriate background cellular milieu
Other investigations
Thyroid storm
History
weight loss, tremors, palpitations, diarrhoea, diaphoresis, fatigue, nausea, vomiting
Exam
tachycardia, history of dropping weight percentiles suggestive of thyrotoxicosis, tremors, goitre, thyroid bruit, agitation, hyper-reflexia, stupor, hepatomegaly
1st investigation
- thyroid stimulating hormone:
suppressed
- T4:
markedly elevated
Other investigations
Serotonin syndrome
History
history of certain medications or medication combinations (e.g., selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, tricyclic antidepressants, etc.); rigors, sweating, twitching, agitation/delirium, headache, nausea, diarrhoea
Exam
tachycardia, hypertension, dilated pupils, tremor, hyper-reflexia, clonus, muscle rigidity, ocular or inducible clonus, agitation, diaphoresis, hyperactive bowel sounds, shock
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Serum sickness/serum sickness-like reaction
History
history of exposure to serum (serum sickness) such as rabies vaccine, crotalid antivenom; onset 1-3 weeks after drug exposure such as penicillins, trimethoprim-sulfamethoxazole that recurs on rechallenge (serum sickness-like reaction); rash, joint pains, malaise, pruritus
Exam
polyarthritis, urticaria
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Factitious fever
History
older child/adolescent; inconsistent history/symptoms, psychosocial history; socially isolated[123]
Exam
normal examination; indifferent affect
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Factitious disorder imposed on another (formerly Munchausen syndrome by proxy)
History
young child; inconsistent history/symptoms, psychosocial history, previous history of child abuse or concerns
Exam
may be normal; may have signs of physical abuse (bruises, retinal haemorrhages, fractures)
1st investigation
- no initial test:
clinical diagnosis
Other investigations
Heat-related illness
History
exposure to hot weather, malaise, confusion, muscle cramps, thirst, poor urine output, seizures
Exam
tachycardia, tachypnoea, vomiting, diarrhoea, dehydration, altered mental status, hypotension; hot, dry skin (frequently but not always)
1st investigation
- FBC:
haemoconcentration, thrombocytopenia
- renal function test:
renal failure
- LFT:
transaminitis
- creatine kinase:
elevated
Other investigations
Paediatric autonomic disorders
History
decreased or increased body temperature, headache, dizziness, syncope, feeding problems, vision problems, recurrent vomiting, hyperhidrosis or hypohidrosis, absent tears, diarrhoea, poor growth, delayed development, Ashkenazi Jewish parents, history of aspiration or vomiting, excessive or diminished sweating, emotional lability, self-mutilation
Exam
hypertension/postural hypotension, absent tears, abnormal reflexes, anisocoria, respiratory dysfunction
1st investigation
- no initial test:
clinical diagnosis
Other investigations
- genetic testing:
positive for known mutation
More
Dengue fever
History
residence in or travel from a dengue-endemic region within past 2 weeks; severe disease is more likely in those aged 1 to 5 years; myalgia, arthralgia, headache (constant frontal); severe retro-orbital pain on eye movement or pressure; symptoms more common in dengue haemorrhagic fever include lethargy, restlessness, pleuritic chest pain, dyspnoea
Exam
fever, skin flushing/rash on face, neck, and chest; exam findings more common in dengue haemorrhagic fever include petechiae, purpura, positive tourniquet test, epistaxis, gingival bleeding, haematemesis, melaena, venipuncture site bleeding, hepatomegaly, abdominal distension, cough; signs of circulatory collapse seen in dengue shock syndrome
1st investigation
- FBC:
leukopenia, thrombocytopenia, elevated haematocrit
More - LFTs:
usually elevated, particularly alanine and aspartate aminotransferases
- serum albumin:
<35 g/L (<3.5 g/dL)
More - serology:
positive
More - reverse transcription-polymerase chain reaction (RT-PCR):
positive
More - non-structural protein 1 (NS1) detection:
positive
More
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