Dengue Fever Haemoconcentration (Hct ↑ by >20% or Hct >45%) + HypoNa < 5 mEq/L Flavivirus – 4 different serotypes ± Haemorrhagic manifestations (petechia, ecchymosis, epistaxis, gum Vector: Aedes aegypti & Aedes albopictus mosquitoes bleeding, hemetemesis, melena, retinal h’age) Incubation period : 3 - 10 days (usually 4 - 6 days). hepatic enlargement & tenderness – poor prognostic signs Infectious period : Within 5 days from onset of the illness. Pleural effusion, hypoalbuminemia, swollen fingers or pedal edema secondary Notifiable disease to increased capillary permeability Pathophysiology: Encephalopathy with N CSF or neurological disturbances (eg seizures, cranial o Increased capillary permeability nerve signs, coma) o rd Diffused capillary leakage of plasma (3 space fluid loss) Acute liver failure: a/w altered mental state, abN neurological signs o Haemoconcentration (hyperreflexia), brain oedema, severe hemorrhage, pul. Oedema, renal failure o ± shock & superimposed infection. WHO classificationSymptoms & signs Grade I Fever, constitutional symptoms, positive tourniquet testProdromal Malaise & headaches for 2 days Grade II Grade I + spontaneous bleedingAcute onset Fever (2-7 days) Scleral injection Grade III Grade II + haemodynamic instability w mental confusion Backache Pain on eye movt Grade IV Grade III + shock Arthralgia, myalgia Lacrimation * cases are accompanied with thrombocytopaenia & haemoconcentration Generalized pain, abdo pain Headache **Grades III & IV denote Dengue Shock Syndrome (DSS) Lymphadenopathy N/V LOA Relative bradycardia Bleeding gums depression th thFever ‘saddle-back’ fever with break on 4 -5 day or continuous fever Presentations usually lasts 7 days Persistent fever > 3 days recalcitrant to RxRash initially transient macular rash Severe backaches, headache, myalgia maculopapular scarlet morbilliform rash Rash: maculopapular or flush; petechial with islands of sparing spreads centrifugally Abdominal symptoms: N/V, epigastric pain, diarrhea (may be mistaken for sparing of palms & soles gastroenteritis or viral gastritis)Clinical manifestations1) Dengue Fever Diagnostic Criteria Characterized by fever, thrombocytopenia, MP petechial rash • Abrupt onset of high fever, continuous and lasting 2 - 7 days, headache, myalgia Dz severity not related to plt count. Plt usu decrease just after fever resolves and arthralgia. around day 5 to 7 • Haemorrhagic manifestations including any of the following: Otherwise similar to other viral fevers - Positive tourniquet test Pruritus over palms usually occur later - Petechiae, purpura, ecchymosis - Epistaxis, gum bleeding2) Dengue Haemorrhagic Shock (DHS) - Haematemesis and/or melaena Usually due to reinfection by another serotype, or in rare cases, a/w infection • Enlargement of liver. of infants with dengue antibodies from mothers 3 • 2 Thrombocytopenia (100,000/mm or less). Thrombocytopenia (<100,000 / mm ) • Haemoconcentration (haematocrit increased by 20% or more)
Correct electrolytes imbalances & metabolic acidosisDx of DHF: The presence of the first two clinical criteria plus thrombocytopenia and Once stabilized, prevent pulmonary oedema by careful IV fluid administrationhaemoconcentration Avoid salicylates for pain relief due to risk of bleeding diathesis and association of dengue with Reye’s syndrome. Avoid hepatotoxic drugs and long acting sedativesDx of DSS: • All the above criteria, plus Disposition • Shock as manifested by rapid and weak pulse with narrowing of pulse pressure Grade I responding to oral fluid hydration w no Cx – home (<20 mmHg, regardless of pressure levels) or hypotension with cold, clammy skin Admit all other PTs for IV fluid therapy (significant dehydration, spontaneous and restlessness. bleeding, bleeding tendency, sever thrombocytopenia, extremes of age, concomitant illnesses) Those with platelet counts between 100-140K can be discharge but should returnInvestigations for f/u serial FBC until platelet normalizesFBC Haemconcentration Leucopaenia (leukocytosis & neutrophilia Complications excludes dengue – consider bacterial DHF – Haemorrhagic tendencies rd infxns) DSS – 3 space fluid loss, hemorrhage, myocarditis (rare) 3 Thrombocytopaenia (<100K / mm ) Abdominal pain – due to pancreatitis, hepatitis or retroperitoneal bleedPT/aPTT Lungs – ARDS, pleural effusion +U/E/Cr hypoNaLFT Abnormal liver enzymes (usu AST>ALT)Dengue serology For IgM, which usually develops on day 5 30% will be negative at day 5PCR if rapid dx required (before 5 days)Management Monitoring: vital signs, haemoconcentration, daily platelets counts (when plt <100K, until upward trend is seen), coagulation profile Fluid replacement: N/S or Ringer solution (avoid over-hydration in DHF. Might ppt pul. oedema) Correct electrolytes imbalances Paracetamol for fever Anti-histamines for pruritus No IM injections Complete rest in bed if platelet <50K due to risk of bleeding from accidental trauma. Digitally signed by DR WANA HLA SHWE Plt transfusion when plt <20K. (Risk of spontaneous bleeding) DN: cn=DR WANA HLA SHWE, c=MY, Note: thrombocytopenia usually worsens AFTER fever resolves o=UCSI University, School of Medicine, KT- Notifiable disease Campus, Terengganu, ou=Internal Medicine Group, firstname.lastname@example.org Reason: This document is for UCSI year 4Acute Mx of DSS students. Date: 2009.02.24 10:41:46 +0800 Monitoring: vital signs, haemoconcentration, daily platelets counts (until upward trend is seen), coagulation profile Oxygen therapy Fluid replacement: N/S or Ringer solution
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