Dengue warning signs and when to admit: a Pakistan guide

Dengue season in Pakistan runs with the monsoon and its aftermath — broadly August through November, with the heaviest case load usually falling in September and October. In a busy OPD during a surge, the clinical question is rarely "is this dengue?" It is "which of these forty febrile patients is about to deteriorate, and which can safely go home?"

WHO's 2009 classification answers that question well, and it is worth knowing properly rather than half-remembering. This is what it actually says.

The single most important idea: deterioration happens as the fever settles

Dengue has three phases — febrile, critical, and recovery. The critical phase begins around defervescence, typically day 3 to day 7 of illness, and lasts roughly 24 to 48 hours. Plasma leakage happens here.

This is counter-intuitive for families and for junior staff. The patient's temperature comes down, everyone relaxes, and that is precisely the window in which shock develops. If you take one thing from this article into your next shift, make it this: a dengue patient whose fever has just settled needs more attention, not less.

Tell the family explicitly: "The fever coming down is not the same as getting better. The next two days are the ones that matter." Families who understand this bring the patient back in time. Families who do not, don't.

The seven warning signs

WHO defines these as "requiring strict observation and medical intervention". Any single one of them changes the disposition.

• Abdominal pain or tenderness
• Persistent vomiting
• Clinical fluid accumulation — ascites, pleural effusion
• Mucosal bleed
• Lethargy or restlessness
• Liver enlargement greater than 2 cm
• Laboratory: rising haematocrit with a concurrent rapid fall in platelet count

Two of these are routinely under-weighted in practice. Restlessness gets attributed to a miserable febrile child or an anxious adult, when it can be an early marker of compromised perfusion. And abdominal pain is often treated as incidental gastritis — it is on this list for a reason.

What counts as severe dengue

Severe dengue is defined by one or more of:

• Severe plasma leakage leading to shock (dengue shock syndrome), or fluid accumulation with respiratory distress
• Severe bleeding, as evaluated by the clinician
• Severe organ involvement — liver with AST or ALT ≥ 1000, CNS with impaired consciousness, or involvement of the heart and other organs

Note that impaired consciousness alone qualifies. Dengue encephalopathy is easy to mislabel as something else in a febrile patient, particularly where cerebral malaria or typhoid are also on the differential.

Who to admit: Groups A, B and C

Two things about Group A are commonly missed. First, it requires both criteria — adequate oral intake and six-hourly urine. A patient with no warning signs who cannot keep fluids down does not qualify for home management. Second, the daily review is part of the disposition, not an optional extra.

And Group B is broader than most people remember. It is not only warning signs. WHO explicitly includes:

• Co-existing conditions — pregnancy, infancy, old age, obesity, diabetes mellitus, renal failure, chronic haemolytic disease
• Social circumstances — living alone, or living far from a health facility without reliable means of transport

That second category deserves emphasis in Pakistani practice. A patient from a rural catchment with no transport after dark, no phone, and a three-hour journey to the nearest facility is a legitimate WHO indication for admission — even with a perfectly reassuring examination. The criterion is not about the disease; it is about whether the patient can get back to you when the critical phase arrives.

The platelet count trap

During a surge, admission decisions in practice often collapse into a single number: the platelet count. It is worth being precise about what WHO's scheme actually says.

The laboratory warning sign is a rising haematocrit together with a rapidly falling platelet count. It is the combination and the trend that carry meaning — haemoconcentration signalling plasma leakage, alongside consumption. An isolated platelet figure, taken once, without a haematocrit and without a previous value to compare against, is not the WHO criterion.

In practical terms this cuts both ways. A patient with a platelet count of 80,000 that has been stable for two days, with a normal haematocrit, no warning signs and good oral intake, is not automatically an admission under WHO. And a patient with a platelet count of 150,000 that has halved since yesterday, with a rising haematocrit, is showing you the warning sign even though the absolute number looks comfortable.

Provincial protocols during epidemic surges may impose their own platelet thresholds for pragmatic reasons — bed management, follow-up reliability, transfusion logistics. Where your provincial guidance sets a threshold, follow it. But understand that it is a local operational decision layered on top of WHO's scheme, not the WHO criterion itself.

Analgesia: paracetamol only

WHO is unambiguous. Paracetamol for high fever if the patient is uncomfortable, at intervals of not less than six hours, with tepid sponging if fever persists.

No aspirin. No ibuprofen. No other NSAIDs. They may aggravate gastritis and bleeding, and aspirin carries the additional risk of Reye's syndrome.

This is worth asking about directly rather than assuming, because analgesics are widely available over the counter here and many patients have already self-medicated before they reach you. "What have you taken for the fever?" is a more useful question than "are you on any medication?" — people frequently do not consider a strip of painkillers from the corner pharmacy to be medication.

What to tell a Group A patient before they leave

WHO's home-care instruction is to return to hospital immediately if any of the following occur:

• No clinical improvement
• Deterioration around the time the fever settles
• Severe abdominal pain
• Persistent vomiting
• Cold and clammy extremities
• Lethargy or irritability / restlessness
• Bleeding — black stools or coffee-ground vomiting
• Not passing urine for more than 4–6 hours

Give this verbally and in writing, and give it to whoever will actually be watching the patient — which is often not the patient. Encourage oral rehydration solution, fruit juice and other fluids containing electrolytes and sugar, with the caveat that sugary fluids may worsen hyperglycaemia in a diabetic patient.

Triage it quickly

Our dengue warning signs checker implements this classification directly: tick the features present and it returns the WHO category, the management group, and the specific findings that drove the decision — so you can see the reasoning rather than just a verdict. It deliberately does not calculate fluid volumes; those belong at the bedside, titrated against serial haematocrit.

Bottom line

Watch the patient whose fever has just broken. Treat restlessness and abdominal pain as the warning signs they are. Remember that Group B includes co-morbidity and social circumstance, not just clinical findings. Read the platelet count alongside the haematocrit and against yesterday's value, never alone. And ask what the patient has already taken, because it is often ibuprofen.

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