Hand-foot-and-mouth disease and enterovirus infection — formative SAQs

SAQ 1 (10 marks)

A 22-month-old boy is brought to the emergency department on day three of a febrile illness. He has classic hand-foot-and-mouth disease — painful oral ulcers and vesicles on the palms, soles and buttocks. Over the past twelve hours the parents have noticed brief jerks of his limbs during sleep and this morning he has been unsteady when trying to walk. He is febrile at 38.9°C, tachycardic at 150/min with a blood pressure of 118/76 mmHg, and intermittently irritable. ^[2]

Question: Outline the immediate and stepwise management of this child, including recognition of the complication, investigations, supportive and critical care, and the conversation with the family. (10 marks) ^[8]

Model answer

Recognition and disposition (2 marks). This child has enterovirus 71 brainstem encephalitis complicating HFMD. Sleep myoclonus and ataxia in a child with HFMD on day three are the classical early brainstem signs, and the tachycardia and borderline-high blood pressure raise concern for early autonomic dysregulation. Admit immediately to a monitored bed and alert the paediatric intensive care unit; the window between tremor and pulmonary oedema can be brief. ^{[2] [5]}

Investigations (2 marks). Send vesicle fluid, throat and stool PCR for enterovirus with EV71 subtyping — stool remains positive for weeks, while vesicle and throat samples are most sensitive while lesions are present. Arrange cerebrospinal fluid analysis after stabilisation (lymphocytic pleocytosis, possible EV71 PCR) and magnetic resonance imaging of brain and spine, which may show characteristic brainstem signal change. An N-terminal pro-B-type natriuretic peptide may be sent as a prognostic marker of cardiac strain. ^{[5] [7]}

Supportive and critical care (3 marks). Secure the airway and observe continuously for autonomic and respiratory deterioration. The haemodynamic strategy is specific: judicious fluid restriction with milrinone and vasoactive support to counter brainstem-driven sympathetic overdrive and vascular leak — avoid generous fluid boluses, which worsen pulmonary oedema. At the first sign of tachypnoea, desaturation or pulmonary oedema, ventilate with lung-protective settings and consider ECMO capability for refractory failure. State honestly that there is no proven antiviral and that intravenous immunoglobulin is used empirically on weak evidence. ^{[7] [8]}

Infection control and the family conversation (3 marks). Maintain contact and droplet precautions, and explain to the family that this is the dangerous end of a usually-mild illness — the same rash with a different virus. Discuss the possibility of deterioration and the rationale for intensive monitoring, while arranging childcare exclusion and household hand hygiene. Notify the case appropriately, and reinforce that prevention rests on hygiene because there is no routine EV71 vaccine in ANZ. Plan multidisciplinary rehabilitation for any persistent neurological deficit in survivors. ^{[8] [2]}